#LyX 1.3 created this file. For more info see http://www.lyx.org/
\lyxformat 221
-\textclass article
+\textclass book
\begin_preamble
-\usepackage[colorlinks=true,linkcolor=blue]{hyperref}
+\usepackage[
+ pdftitle={SDCC Compiler User Guide},
+ pdfauthor={SDCC development team},
+ pdfsubject={installation, user manual},
+ pdfkeywords={8032, 8051, ansi, c, compiler, CPU, DS390,
+ embedded, GPL, HC08, manual, mcs51, PIC, Z80},
+ colorlinks=true,
+ linkcolor=blue] {hyperref}
+%
+\sloppy
+\tolerance=500
+\emergencystretch=30pt
+%
\date{}
\end_preamble
\language english
\graphics default
\paperfontsize default
\spacing single
-\papersize Default
+\papersize letterpaper
\paperpackage a4
\use_geometry 1
\use_amsmath 0
\use_numerical_citations 0
\paperorientation portrait
\leftmargin 30mm
-\topmargin 10mm
+\topmargin 20mm
\rightmargin 25mm
-\bottommargin 15mm
+\bottommargin 20mm
\secnumdepth 3
\tocdepth 3
\paragraph_separation indent
Two resp.
three consecutive dashes simply result in a long resp.
extra long dash.
+\layout Comment
+
+Architecture specific stuff (like memory models, code examples) should maybe
+ later go
+\layout Comment
+
+into seperate sections/chapters/appendices (it is hard to document PIC or
+ Z80 in
+\layout Comment
+
+a 8051 centered document) - for now simply add.
\layout Title
SDCC Compiler User Guide
-\layout Standard
-\align center
-2003-05-28
+\layout Date
+
+
+\size normal
+SDCC 2.4.0
+\size footnotesize
+
+\newline
+$Date$
+\newline
+$Revision$
+\layout Comment
+
+The above strings enclosed in $ are automatically updated by cvs
\layout Standard
\end_inset
-\layout Section
-\pagebreak_top
+\layout Chapter
+
Introduction
-\layout Subsection
+\layout Section
About SDCC
\layout Standard
\series bold
SDCC
\series default
- is a Freeware, retargettable, optimizing ANSI-C compiler by
+ (
+\emph on
+S
+\emph default
+mall
+\emph on
+D
+\emph default
+evice
+\emph on
+C
+\emph default
+
+\emph on
+C
+\emph default
+ompiler) is a Freeware, retargettable, optimizing ANSI-C compiler by
\series bold
Sandeep Dutta
\series default
designed for 8 bit Microprocessors.
The current version targets Intel MCS51 based Microprocessors (8031, 8032,
8051, 8052
-\begin_inset LatexCommand \index{8031, 8032, 8051, 8052 CPU}
+\begin_inset LatexCommand \index{8031, 8032, 8051, 8052, mcs51 CPU}
\end_inset
-, etc), Zilog Z80 based MCUs, and the Dallas DS80C390 variant.
- It can be retargetted for other microprocessors, support for PIC, AVR and
- 186 is under development.
+, etc.), Dallas DS80C390 variants, Motorola HC08 and Zilog Z80 based MCUs.
+ It can be retargetted for other microprocessors, support for Microchip
+ PIC, Atmel AVR is under development.
The entire source code for the compiler is distributed under GPL.
SDCC uses ASXXXX & ASLINK, a Freeware, retargettable assembler & linker.
SDCC has extensive language extensions suitable for utilizing various microcont
dead code elimination
\layout Itemize
-jumptables for
+jump tables for
\emph on
switch
\emph default
\newline
The latest version can be downloaded from
-\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
\end_inset
\end_inset
.
-\layout Subsection
+\layout Section
Open Source
\layout Standard
You are forbidden to forbid anyone else to use, share and improve what
you give them.
Help stamp out software-hoarding!
-\layout Subsection
+\layout Section
Typographic conventions
\begin_inset LatexCommand \index{Typographic conventions}
Interesting items and new terms are printed in
\emph on
italic.
-\layout Subsection
+\layout Section
Compatibility with previous versions
\layout Standard
\end_inset
-.
+ (see section
+\begin_inset LatexCommand \ref{sub:ANSI-Compliance}
+
+\end_inset
+
+ for ANSI-Compliance).
\newline
(8 bits) which is not ANSI compliant
\layout Itemize
-the default directory for gcc-builds where include, library and documention
+the default directory for gcc-builds where include, library and documentation
files are stored is now in /usr/local/share
\layout Itemize
\emph on
<pending: more incompatibilities?>
-\layout Subsection
+\layout Section
System Requirements
\layout Standard
For Windows some pre-compiled binary distributions are available for your
convenience.
You should have some experience with command line tools and compiler use.
-\layout Subsection
+\layout Section
Other Resources
\layout Standard
their own documentation and can be found in the source distribution.
If you want the latest unreleased software, the complete source package
is available directly by anonymous CVS on cvs.sdcc.sourceforge.net.
-\layout Comment
-
-ANSI C reference / related tools / recommended reading / compiler building:
- Muchnik?
-\layout Subsection
+\layout Section
Wishes for the future
\layout Standard
support for mcs51
\newline
+\newline
+
\family default
-If you can think of some more, please see the chapter 9 about filing feature
- requests
+If you can think of some more, please see the section
+\begin_inset LatexCommand \ref{sub:Requesting-Features}
+
+\end_inset
+
+ about filing feature requests
\begin_inset LatexCommand \index{Requesting features}
\end_inset
-\begin_inset LatexCommand \index{Feature requests}
+\begin_inset LatexCommand \index{Feature request}
\end_inset
.
\newline
-\layout Section
-\pagebreak_top
-Installation
+\layout Chapter
+
+Installing SDCC
\begin_inset LatexCommand \index{Installation}
\end_inset
-\layout Subsection
+\layout Standard
+
+For most users it is sufficient to skip to either section
+\begin_inset LatexCommand \ref{sub:Building-SDCC-on-Linux}
+
+\end_inset
+
+ or section
+\begin_inset LatexCommand \ref{sub:Windows-Install}
+
+\end_inset
+
+.
+ More detailled instructions follow below.
+\layout Section
Configure Options
\begin_inset LatexCommand \index{Options SDCC configuration}
The install paths, search paths and other options are defined when running
'configure'.
- The defaults can be overriden by:
+ The defaults can be overridden by:
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--prefix see tabel below
+-prefix see table below
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--exec_prefix see tabel below
+-exec_prefix see table below
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--bindir see tabel below
+-bindir see table below
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--datadir see tabel below
+-datadir see table below
\layout List
\labelwidthstring 00.00.0000
-docdir environment variable, see tabel below
+docdir environment variable, see table below
\layout List
\labelwidthstring 00.00.0000
-include_dir_suffix environment variable, see tabel below
+include_dir_suffix environment variable, see table below
\layout List
\labelwidthstring 00.00.0000
-lib_dir_suffix environment variable, see tabel below
+lib_dir_suffix environment variable, see table below
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--z80-port Excludes the z80 port
+-disable-z80-port Excludes the z80 port
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
+-disable-hc08-port Excludes the HC08 port
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
-disable-pic-port Excludes the PIC port
\layout List
\labelwidthstring 00.00.0000
STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
At the moment it's not possible to change the default settings (it was
- simply never required.
+ simply never required).
\newline
\newline
These defaults are:
\newline
-\newline
+\layout Standard
+\align center
\begin_inset Tabular
<lyxtabular version="3" rows="8" columns="3">
\newline
-\newline
-
-\newline
+\layout Standard
+\noindent
'configure' also computes relative paths.
This is needed for full relocatability of a binary package and to complete
search paths (see section search paths below):
\newline
-\newline
+\layout Standard
+\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
\layout Standard
..
-\backslash
-
\end_inset
</cell>
</row>
\newline
-\newline
+\layout Standard
+\noindent
Examples:
\layout LyX-Code
./configure
-\layout LyX-Code
+\newline
+./configure -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
-./configure --prefix=
+-prefix=
\begin_inset Quotes srd
\end_inset
\begin_inset Quotes srd
\end_inset
- --datadir=
+ -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-datadir=
\begin_inset Quotes srd
\end_inset
\end_inset
-\layout LyX-Code
+\newline
+./configure -
+\begin_inset ERT
+status Collapsed
-./configure --disable-avr-port --disable-xa51-port
\layout Standard
-To crosscompile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw3
-2'):
-\layout LyX-Code
+\backslash
+/
+\end_inset
+
+-disable-avr-port -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
-./configure
\backslash
+/
+\end_inset
+
+-disable-xa51-port
+\layout Standard
+To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
+32'):
\layout LyX-Code
- CC=
+./configure
+\backslash
+
+\newline
+CC=
\begin_inset Quotes srd
\end_inset
\backslash
-
-\layout LyX-Code
-
- RANLIB=
+
+\newline
+RANLIB=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- STRIP=
+\newline
+STRIP=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
- --prefix=
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-prefix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
- --datadir=
+-datadir=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- docdir=
+\newline
+docdir=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- include_dir_suffix=
+\newline
+include_dir_suffix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- lib_dir_suffix=
+\newline
+lib_dir_suffix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- sdccconf_h_dir_separator=
+\newline
+sdccconf_h_dir_separator=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
- --disable-device-lib-build
\backslash
+/
+\end_inset
-\layout LyX-Code
+-disable-device-lib-build
+\backslash
- --disable-ucsim
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-disable-ucsim
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
- --host=i586-mingw32msvc --build=unknown-unknown-linux-gnu
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-host=i586-mingw32msvc -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-build=unknown-unknown-linux-gnu
\layout Standard
To
\begin_inset Quotes srd
\end_inset
-compile on Cygwin for Mingw32(see also sdcc/support/scripts/sdcc_cygwin_mingw32)
-:
+compile on Cygwin for Mingw32 (see also sdcc/support/scripts/sdcc_cygwin_mingw32
+):
\layout LyX-Code
./configure -C
\backslash
-\layout LyX-Code
-
- CFLAGS=
+\newline
+CFLAGS=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- LDFLAGS=
+\newline
+LDFLAGS=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
- --prefix=
+-prefix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
- --datadir=
+\backslash
+/
+\end_inset
+
+-datadir=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- docdir=
+\newline
+docdir=
\begin_inset Quotes srd
\end_inset
\backslash
-
-\layout LyX-Code
-
- include_dir_suffix=
+
+\newline
+include_dir_suffix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- lib_dir_suffix=
+\newline
+lib_dir_suffix=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
-
- sdccconf_h_dir_separator=
+\newline
+sdccconf_h_dir_separator=
\begin_inset Quotes srd
\end_inset
\backslash
-\layout LyX-Code
+\newline
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
- --disable-ucsim
+-disable-ucsim
\layout Standard
'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
-C' turns on caching, which gives a little bit extra speed.
However if options are changed, it can be necessary to delete the config.cache
file.
-\layout Subsection
+\layout Section
Install paths
-\begin_inset LatexCommand \index{Install paths}
+\begin_inset LatexCommand \label{sub:Install-paths}
\end_inset
-\layout Standard
+\begin_inset LatexCommand \index{Install paths}
-1.
- Binary files (preprocessor, assembler and linker)
-\layout Standard
+\end_inset
+\layout Standard
+\added_space_top medskip \align center
+
\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
+<lyxtabular version="3" rows="5" columns="4">
<features>
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
+
+\series bold
+Description
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\series bold
Path
\end_inset
</cell>
\layout Standard
-default
+
+\series bold
+Default
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
+
+\series bold
Win32 builds
\end_inset
</cell>
</row>
-<row topline="true" bottomline="true">
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Binary files*
+\end_inset
+</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\end_inset
</cell>
</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
-
-\newline
-2.
- Include files
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="block" valignment="top" leftline="true" width="1.6in">
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
+<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-Path
+Include files
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-default
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
\emph on
-$DATADIR/
-\newline
-$INCLUDE_DIR_SUFFIX
+$DATADIR/ $INCLUDE_DIR_SUFFIX
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\end_inset
</cell>
</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
-
-\newline
-3.
- Library files (the
-\shape italic
-model
-\shape default
- is auto-appended by the compiler, e.g.
- small, large, z80, ds390 etc.)
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Path
-\end_inset
-</cell>
+<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-default
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
+Library file**
\end_inset
</cell>
-</row>
-<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\end_inset
</cell>
</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
-
-\newline
-4.
- Documentation
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-Path
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-default
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
+Documentation
\end_inset
</cell>
-</row>
-<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\end_inset
-\newline
+\layout Verse
+
+\size footnotesize
+*compiler, preprocessor, assembler, and linker
\newline
+**the
+\shape italic
+model
+\shape default
+ is auto-appended by the compiler, e.g.
+ small, large, z80, ds390 etc
+\layout Standard
+\noindent
The install paths can still be changed during `make install` with e.g.:
\layout LyX-Code
\layout Standard
Of course this doesn't change the search paths compiled into the binaries.
-\layout Subsection
+\layout Section
Search Paths
+\begin_inset LatexCommand \label{sub:Search-Paths}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{Search path}
\end_inset
1.
Binary files (preprocessor, assembler and linker)
\newline
-
+
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
\newline
-\newline
+\layout Standard
+\noindent
2.
Include files
\newline
-
+
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
\newline
-\newline
- The option -
+\layout Standard
+\noindent
+The option -
\begin_inset ERT
status Collapsed
3.
Library files
\newline
+
+\layout Standard
+
With the exception of
\begin_inset Quotes sld
\end_inset
\newline
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
\end_inset
+\newline
+
\layout Comment
Don't delete any of the stray spaces in the table above without checking
\end_inset
-nostdlib disables the last two search paths.
-\layout Subsection
+\layout Section
Building SDCC
\begin_inset LatexCommand \index{Building SDCC}
\end_inset
-\layout Subsubsection
+\layout Subsection
Building SDCC on Linux
+\begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}
+
+\end_inset
+
+
\layout Enumerate
\series medium
Download the source package
\series default
- either from the SDCC CVS repository or from the
-\begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
-
-\end_inset
-
-
+ either from the SDCC CVS repository or from the nightly snapshots
\series medium
, it will be named something like sdcc
\series default
\series default
ar.
\series medium
-gz.
+gz
+\series default
+
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
+
+\end_inset
+
+.
\layout Enumerate
Unpack the file using a command like:
\family sans
\series bold
-"tar -xzf sdcc.src.tar.gz
+"tar -xvzf sdcc.src.tar.gz
\family default
\series default
"
\series default
This copies the binary executables, the include files, the libraries and
the documentation to the install directories.
-\layout Subsubsection
+ Proceed with section
+\begin_inset LatexCommand \ref{sec:Testing-the-SDCC}
+
+\end_inset
+
+.
+\layout Subsection
Building SDCC on OSX 2.x
\layout Standard
\layout LyX-Code
./configure CC=gcc2 CXX=g++2
-\layout Subsubsection
+\layout Subsection
-Crosscompiling SDCC on Linux for Windows
+Cross compiling SDCC on Linux for Windows
\layout Standard
-With the Mingw32 gcc crosscompiler it's easy to compile SDCC for Win32.
+With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
See section 'Configure Options'.
-\layout Subsubsection
+\layout Subsection
Building SDCC on Windows
\layout Standard
With the exception of Cygwin the SDCC binaries uCsim and sdcdb can't be
built on Windows.
They use Unix-sockets, which are not available on Win32.
-\layout Subsubsection
+\layout Subsection
-Windows Install Using a Binary Package
-\layout Enumerate
-
-Download the binary package and unpack it using your favorite unpacking
- tool (gunzip, WinZip, etc).
- This should unpack to a group of sub-directories.
- An example directory structure after unpacking the mingw32 package is:
- c:
-\backslash
-sdcc
-\backslash
-bin for the executables, c:
-\backslash
-sdcc
-\backslash
-include and c:
-\backslash
-sdcc
-\backslash
-lib for the include and libraries.
-\layout Enumerate
-
-Adjust your environment variable PATH to include the location of the bin
- directory or start sdcc using the full path.
-\layout Subsubsection
-
-Building SDCC using Cygwin and Mingw32
-\layout Standard
+Building SDCC using Cygwin and Mingw32
+\layout Standard
For building and installing a Cygwin executable follow the instructions
for Linux.
Win32-binary can be built, which will not need the Cygwin-DLL.
For the necessary 'configure' options see section 'configure options' or
- the script 'sdcc/support/scripts/sdcc_cygwinmingw32'.
+ the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
\newline
\newline
Replace in your cygwin.bat the line
\layout LyX-Code
-bash --login -i
+bash -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-login -i
\layout Standard
with (one line):
rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
\layout LyX-Code
- -bg black -fg white -geometry 100x65 -e bash --login
+ -bg black -fg white -geometry 100x65 -e bash -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-login
\layout Standard
Text selected with the mouse is automatically copied to the clipboard, pasting
\layout Standard
SDCC sources use the unix line ending LF.
- Life is much easier, if you store the source tree on a drive, which is
- mount in binary mode.
+ Life is much easier, if you store the source tree on a drive which is mounted
+ in binary mode.
And use an editor which can handle LF-only line endings.
Make sure not to commit files with windows line endings.
-\layout Subsubsection
+ The tabulator spacing
+\begin_inset LatexCommand \index{tabulator spacing (8)}
+
+\end_inset
+
+ used in the project is 8.
+\layout Subsection
-Windows Install Using Microsoft Visual C++ 6.0/NET
+Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
\layout Standard
\series default
SDCC is distributed with all the projects, workspaces, and files you need
- to build it using Visual C++ 6.0/NET.
+ to build it using Visual C++ 6.0/NET (except for sdcdb.exe which currently
+ doesn't build under MSVC).
The workspace name is 'sdcc.dsw'.
Please note that as it is now, all the executables are created in a folder
called sdcc
\backslash
bin_vc to sdcc
\backslash
-bin before runnng SDCC.
+bin before running SDCC.
\newline
\newline
-In order to build SDCC with Visual C++ 6.0/NET you need win32 executables
- of bison.exe, flex.exe, and gawk.exe.
+In order to build SDCC with MSVC you need win32 executables of bison.exe,
+ flex.exe, and gawk.exe.
One good place to get them is
\begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
\end_inset
.zip.
- Now you have to install the utilities and setup Visual C++ so it can locate
- the required programs.
+ Now you have to install the utilities and setup MSVC so it can locate the
+ required programs.
Here there are two alternatives (choose one!):
\layout Enumerate
\backslash
bin_vc to sdcc
\backslash
-bin, and you can compile using sdcc.
-\layout Subsubsection
+bin, and you can compile using SDCC.
+\layout Subsection
-Windows Install Using Borland
+Building SDCC Using Borland
\layout Enumerate
From the sdcc directory, run the command "make -f Makefile.bcc".
sdcdb.exe (which currently doesn't build under Borland C++).
\layout Enumerate
-If you modify any source files and need to rebuild, be aware that the dependanci
+If you modify any source files and need to rebuild, be aware that the dependenci
es may not be correctly calculated.
The safest option is to delete all .obj files and run the build again.
- From a Cygwin BASH prompt, this can easily be done with the commmand:
+ From a Cygwin BASH prompt, this can easily be done with the command (be
+ sure you are in the sdcc directory):
\newline
\newline
\newline
\newline
-or on Windows NT/2000/XP from the command prompt with the commmand:
+or on Windows NT/2000/XP from the command prompt with the command:
\newline
\family sans
from the sdcc directory.
\layout Subsection
+Windows Install Using a Binary Package
+\begin_inset LatexCommand \label{sub:Windows-Install}
+
+\end_inset
+
+
+\layout Enumerate
+
+Download the binary package from
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
+
+\end_inset
+
+ and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
+ This should unpack to a group of sub-directories.
+ An example directory structure after unpacking the mingw32 package is:
+ c:
+\backslash
+sdcc
+\backslash
+bin for the executables, c:
+\backslash
+sdcc
+\backslash
+include and c:
+\backslash
+sdcc
+\backslash
+lib for the include and libraries.
+\layout Enumerate
+
+Adjust your environment variable PATH to include the location of the bin
+ directory or start sdcc using the full path.
+\layout Section
+
Building the Documentation
\layout Standard
-...
- coming soon
-\layout Subsection
+If the necessary tools (LyX, LaTeX, LaTeX2HTML) are installed it is as easy
+ as changing into the doc directory and typing
+\family sans
+\series bold
+
+\begin_inset Quotes srd
+\end_inset
+
+make
+\begin_inset Quotes srd
+\end_inset
+
+
+\family default
+\series default
+ there.
+ You're invited to make changes and additions to this manual (sdcc/doc/sdccman.ly
+x).
+ Using LyX
+\begin_inset LatexCommand \url{www.lyx.org}
+
+\end_inset
+
+ as editor this is straightforward.
+ If you want to avoid installing the tools you will have some success with
+ a bootable Knoppix CD
+\begin_inset LatexCommand \url{http://www.knoppix.net}
+
+\end_inset
+
+.
+ Prebuilt documentation in html and pdf format is available from
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
+
+\end_inset
+
+.
+\layout Section
+
+Reading the Documentation
+\layout Standard
+
+Currently reading the document in pdf format is recommended, as for unknown
+ reason the hyperlinks are working there whereas in the html version they
+ are not
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+If you should know why please drop us a note
+\end_inset
+
+.
+ You'll find the pdf version at
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}
+
+\end_inset
+
+.
+\newline
+This documentation is in some aspects different from a commercial documentation:
+
+\layout Itemize
+
+It tries to document SDCC for several processor architectures in one document
+ (commercially these probably would be separate documents/products).
+ This document
+\begin_inset LatexCommand \index{Status of documentation}
+
+\end_inset
+
+ currently matches SDCC for mcs51 and DS390 best and does give too few informati
+on about f.e.
+ Z80, PIC14, PIC16 and HC08.
+\layout Itemize
+
+There are many references pointing away from this documentation.
+ Don't let this distract you.
+ If there f.e.
+ was a reference like
+\begin_inset LatexCommand \url{www.opencores.org}
+
+\end_inset
+
+ together with a statement
+\begin_inset Quotes sld
+\end_inset
+
+some processors which are targetted by SDCC can be implemented in a
+\emph on
+f
+\emph default
+ield
+\emph on
+p
+\emph default
+rogrammable
+\emph on
+g
+\emph default
+ate
+\emph on
+a
+\emph default
+rray
+\begin_inset LatexCommand \index{fpga (field programmable gate array)}
+
+\end_inset
+
+
+\begin_inset Quotes srd
+\end_inset
+
+ we expect you to have a quick look there and come back.
+ If you read this you are on the right track.
+\layout Itemize
+
+Some sections attribute more space to problems, restrictions and warnings
+ than to the solution.
+\layout Itemize
+
+The installation section and the section about the debugger is intimidating.
+\layout Itemize
+
+There are still lots of typos and there are more different writing styles
+ than pictures.
+\layout Section
+
+Testing the SDCC Compiler
+\begin_inset LatexCommand \label{sec:Testing-the-SDCC}
+
+\end_inset
+
-Testing out the SDCC Compiler
\layout Standard
The first thing you should do after installing your SDCC compiler is to
If it doesn't run, or gives a message about not finding sdcc program, then
you need to check over your installation.
Make sure that the sdcc bin directory is in your executable search path
- defined by the PATH environment setting (see the Trouble-shooting section
- for suggestions).
+ defined by the PATH environment setting (
+\series medium
+see
+\series default
+section
+\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
+
+\end_inset
+
+\SpecialChar ~
+
+\series medium
+Install trouble-shooting for suggestions
+\series default
+).
Make sure that the sdcc program is in the bin folder, if not perhaps something
did not install correctly.
\newline
\begin_inset Quotes srd
\end_inset
-
+.
\newline
\newline
Make sure the compiler works on a very simple example.
Type in the following test.c program using your favorite
\series default
-ascii
+ASCII
\series medium
editor:
-\series default
+\layout Verse
-\newline
\family typewriter
-
-\newline
char test;
\newline
test=0;
\newline
}
-\family default
-
-\newline
-
-\emph on
+\layout Standard
-\newline
\series medium
-\emph default
Compile this using the following command:
\family sans
\series bold
\series medium
(no test.ihx, and the linker generates warnings), then the problem is most
- likely that sdcc cannot find the
+ likely that
+\series default
+SDCC
+\series medium
+ cannot find the
\series default
/
\series medium
\series default
\series medium
-(see the Install trouble-shooting section for suggestions).
+(see
+\series default
+section
+\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
+
+\end_inset
+
+\SpecialChar ~
+
+\series medium
+Install trouble-shooting for suggestions).
\series default
\newline
\newline
\series medium
-The final test is to ensure sdcc can use the
+The final test is to ensure
+\series default
+SDCC
+\series medium
+ can use the
\series default
standard
\series medium
header files and libraries.
Edit test.c and change it to the following:
-\series default
+\layout Verse
-\newline
-
-\newline
\family typewriter
#include <string.h>
strcpy(str1, "testing");
\newline
}
-\newline
+\layout Standard
-\newline
-\family default
\series medium
Compile this by typing
\family sans
.
This should generate a test.ihx output file, and it should give no warnings
such as not finding the string.h file.
- If it cannot find the string.h file, then the problem is that sdcc cannot
- find the /usr/local/share/sdcc/include directory
+ If it cannot find the string.h file, then the problem is that
+\series default
+SDCC
+\series medium
+ cannot find the /usr/local/share/sdcc/include directory
\series default
\series medium
-(see the Install trouble-shooting section for suggestions).
-\layout Subsection
+(see the
+\series default
+section
+\begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
+
+\end_inset
+
+\SpecialChar ~
+
+\series medium
+Install trouble-shooting section for suggestions).
+
+\series default
+ Use option
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-print-search-dirs
+\series default
+
+\begin_inset LatexCommand \index{-\/-print-search-dirs}
+
+\end_inset
+
+ to find exactly where SDCC is looking for the include and lib files.
+\layout Section
Install Trouble-shooting
+\begin_inset LatexCommand \label{sub:Install-Trouble-shooting}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{Install trouble-shooting}
\end_inset
-\layout Subsubsection
+\layout Subsection
-SDCC does not build correctly.
+If SDCC does not build correctly
\layout Standard
A thing to try is starting from scratch by unpacking the .tgz source package
If anything goes wrong, you can review the log files to locate the problem.
Or a relevant part of this can be attached to an email that could be helpful
when requesting help from the mailing list.
-\layout Subsubsection
+\layout Subsection
What the
\begin_inset Quotes sld
to ensure the source package compiles on your system.
It will take a few minutes to run, and will compile a few tests to determine
what compiler features are installed.
-\layout Subsubsection
+\layout Subsection
What the
\begin_inset Quotes sld
\begin_inset Quotes srd
\end_inset
- does.
+ does
\layout Standard
This runs the GNU make tool, which automatically compiles all the source
packages into the final installed binary executables.
-\layout Subsubsection
+\layout Subsection
What the
\begin_inset Quotes sld
\layout Standard
This will install the compiler, other executables libraries and include
- files in to the appropriate directories.
- See section
-\begin_inset Quotes sld
-\end_inset
+ files into the appropriate directories.
+ See sections
+\begin_inset LatexCommand \ref{sub:Install-paths}
-Install and Search PATHS
-\begin_inset Quotes srd
\end_inset
-.
+,\SpecialChar ~
+
+\begin_inset LatexCommand \ref{sub:Search-Paths}
+
+\end_inset
+
+\SpecialChar ~
+about install and search paths.
\newline
-On most systems you will need super-user privilages to do this.
-\layout Subsection
+On most systems you will need super-user privileges to do this.
+\layout Section
Components of SDCC
\layout Standard
As development for other processors proceeds, this list will expand to include
executables to support processors like AVR, PIC, etc.
-\layout Subsubsection
+\layout Subsection
sdcc - The Compiler
\layout Standard
This is the actual compiler, it in turn uses the c-preprocessor and invokes
the assembler and linkage editor.
-\layout Subsubsection
+\layout Subsection
-sdcpp
-\begin_inset LatexCommand \index{sdcpp}
+sdcpp - The C-Preprocessor
+\layout Standard
-\end_inset
+The preprocessor
+\begin_inset LatexCommand \index{sdcpp (preprocessor)}
- - The C-Preprocessor
-\layout Standard
+\end_inset
-The preprocessor is a modified version of the GNU preprocessor.
+ is a modified version of the GNU preprocessor.
The C preprocessor is used to pull in #include sources, process #ifdef
statements, #defines and so on.
-\layout Subsubsection
+\layout Subsection
-asx8051, as-z80, as-gbz80, aslink, link-z80, link-gbz80 - The Assemblers
- and Linkage Editors
+as
+\emph on
+xxxx
+\emph default
+, aslink, link-
+\emph on
+xxx
+\emph default
+ - The Assemblers and Linkage Editors
\layout Standard
This is retargettable assembler & linkage editor, it was developed by Alan
Baldwin.
John Hartman created the version for 8051, and I (Sandeep) have made some
- enhancements and bug fixes for it to work properly with the SDCC.
-\layout Subsubsection
+ enhancements and bug fixes for it to work properly with SDCC.
+\layout Subsection
s51 - The Simulator
+\layout Standard
+
+S51
\begin_inset LatexCommand \index{s51}
\end_inset
-
-\layout Standard
-
-S51 is a freeware, opensource simulator developed by Daniel Drotos (
+ is a freeware, opensource simulator developed by Daniel Drotos (
\begin_inset LatexCommand \url{mailto:drdani@mazsola.iit.uni-miskolc.hu}
\end_inset
).
The simulator is built as part of the build process.
- For more information visit Daniel's website at:
+ For more information visit Daniel's web site at:
\begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
\end_inset
.
- It currently support the core mcs51, the Dallas DS80C390 and the Philips
+ It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
XA51 family.
-\layout Subsubsection
+\layout Subsection
-sdcdb
-\begin_inset LatexCommand \index{sdcdb}
+sdcdb - Source Level Debugger
+\layout Standard
+
+Sdcdb
+\begin_inset LatexCommand \index{sdcdb (debugger)}
\end_inset
- - Source Level Debugger
-\layout Standard
+ is the companion source level debugger.
+ More about sdcdb in section
+\begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
+
+\end_inset
+
+.
+ The current version of the debugger uses Daniel's Simulator S51
+\begin_inset LatexCommand \index{s51}
+
+\end_inset
+
+, but can be easily changed to use other simulators.
+
+\layout Chapter
-Sdcdb is the companion source level debugger.
- The current version of the debugger uses Daniel's Simulator S51, but can
- be easily changed to use other simulators.
-\layout Section
-\pagebreak_top
Using SDCC
-\layout Subsection
+\layout Section
Compiling
-\layout Subsubsection
+\layout Subsection
Single Source File Projects
\layout Standard
\family default
\series default
This will compile, assemble and link your source file.
- Output files are as follows
+ Output files are as follows:
\layout Itemize
sourcefile.asm
-\begin_inset LatexCommand \index{.asm}
+\begin_inset LatexCommand \index{<file>.asm}
\end_inset
\layout Itemize
sourcefile.lst
-\begin_inset LatexCommand \index{.lst}
+\begin_inset LatexCommand \index{<file>.lst}
\end_inset
\layout Itemize
sourcefile.rst
-\begin_inset LatexCommand \index{.rst}
+\begin_inset LatexCommand \index{<file>.rst}
\end_inset
\layout Itemize
sourcefile.sym
-\begin_inset LatexCommand \index{.sym}
+\begin_inset LatexCommand \index{<file>.sym}
\end_inset
\layout Itemize
sourcefile.rel
-\begin_inset LatexCommand \index{.rel}
+\begin_inset LatexCommand \index{<file>.rel}
+
+\end_inset
+
+ or sourcefile.o
+\begin_inset LatexCommand \index{<file>.o}
\end_inset
\layout Itemize
sourcefile.map
-\begin_inset LatexCommand \index{.map}
+\begin_inset LatexCommand \index{<file>.map}
\end_inset
\layout Itemize
sourcefile.mem
-\begin_inset LatexCommand \index{.mem}
+\begin_inset LatexCommand \index{<file>.mem}
\end_inset
\layout Itemize
sourcefile.ihx
-\begin_inset LatexCommand \index{.ihx}
+\begin_inset LatexCommand \index{<file>.ihx}
\end_inset
\end_inset
.
- If you need another format you might want to use objdump
-\begin_inset LatexCommand \index{objdump}
+ If you need another format you might want to use
+\family sans
+\shape italic
+objdump
+\family default
+\shape default
+
+\begin_inset LatexCommand \index{objdump (tool)}
+
+\end_inset
+
+ or
+\family sans
+\shape italic
+ srecord
+\family default
+\shape default
+
+\begin_inset LatexCommand \index{srecord (tool)}
\end_inset
- or srecord
-\begin_inset LatexCommand \index{srecord}
+).
+ Both formats are documented in the documentation of srecord
+\begin_inset LatexCommand \index{srecord (tool)}
\end_inset
-)
+
\layout Itemize
sourcefile.adb
-\begin_inset LatexCommand \index{.adb}
+\begin_inset LatexCommand \index{<file>.adb}
\end_inset
\layout Itemize
sourcefile.cdb
-\begin_inset LatexCommand \index{.cdb}
+\begin_inset LatexCommand \index{<file>.cdb}
\end_inset
/
\end_inset
--debug) containing debug information
+-debug) containing debug information.
+ The format is documented in cdbfileformat.pdf.
\layout Itemize
sourcefile.
- (no extension)
-\begin_inset LatexCommand \index{. (no extension)}
+\begin_inset LatexCommand \index{<file> (no extension)}
\end_inset
- An optional AOMF51 file containing debug information (with -
+ An optional AOMF or AOMF51
+\begin_inset LatexCommand \index{AOMF, AOMF51}
+
+\end_inset
+
+ file containing debug information (generated with option -
\begin_inset ERT
status Collapsed
/
\end_inset
--debug)
+-debug).
+ The (Intel)
+\emph on
+ a
+\emph default
+bsolute
+\emph on
+o
+\emph default
+bject
+\emph on
+m
+\emph default
+odule
+\emph on
+f
+\emph default
+ormat is commonly used by third party tools (debuggers
+\begin_inset LatexCommand \index{Debugger}
+
+\end_inset
+
+, simulators, emulators)
\layout Itemize
sourcefile.dump*
-\begin_inset LatexCommand \index{.dump*}
+\begin_inset LatexCommand \index{<file>.dump*}
\end_inset
- - Dump file to debug the compiler it self (with -
+ - Dump file to debug the compiler it self (generated with option -
\begin_inset ERT
status Collapsed
\end_inset
-dumpall) (see section
+\begin_inset LatexCommand \ref{sub:Intermediate-Dump-Options}
+
+\end_inset
+
+\SpecialChar ~
+ and section
+\begin_inset LatexCommand \ref{sub:The-anatomy-of}
+
+\end_inset
+
+\SpecialChar ~
+
\begin_inset Quotes sld
\end_inset
\end_inset
).
-\layout Subsubsection
+\layout Subsection
Projects with Multiple Source Files
\layout Standard
\family default
\series default
-\begin_inset LatexCommand \index{.rel}
+\begin_inset LatexCommand \index{<file>.rel}
\end_inset
\noun default
file specified in the command line, since the linkage editor processes
file in the order they are presented to it.
-\layout Subsubsection
+ The linker is invoked from SDCC using a script file with extension .lnk
+\begin_inset LatexCommand \index{<file>.lnk}
+
+\end_inset
+
+.
+ You can view this file to troubleshoot linking problems such as those arising
+ from missing libraries.
+\layout Subsection
Projects with Additional Libraries
\begin_inset LatexCommand \index{Libraries}
for how to create a
\emph on
.lib
-\begin_inset LatexCommand \index{.lib}
+\begin_inset LatexCommand \index{<file>.lib}
\end_inset
\newline
\newline
-The most efficient way to use libraries is to keep seperate modules in seperate
+The most efficient way to use libraries is to keep separate modules in separate
source files.
- The lib file now should name all the modules.rel files.
+ The lib file now should name all the modules.rel
+\begin_inset LatexCommand \index{<file>.rel}
+
+\end_inset
+
+ files.
For an example see the standard library file
\emph on
libsdcc.lib
in the directory <installdir>/share/lib/small.
\layout Subsection
-Command Line Options
-\begin_inset LatexCommand \index{Command Line Options}
+Using sdcclib to Create and Manage Libraries
+\begin_inset LatexCommand \index{sdcclib}
\end_inset
-\layout Subsubsection
+\layout Standard
-Processor Selection Options
-\begin_inset LatexCommand \index{Options processor selection}
+Alternatively, instead of having a .rel file for each entry on the library
+ file as described in the preceding section, sdcclib can be used to embed
+ all the modules belonging to such library in the library file itself.
+ This results in a larger library file, but it greatly reduces the number
+ of disk files accessed by the linker.
+ Additionally, the packed library file contains an index of all include
+ modules and symbols that significantly speeds up the linking process.
+ To display a list of options supported by sdcclib type:
+\newline
-\end_inset
+\layout Standard
-\begin_inset LatexCommand \index{Processor selection options}
+\family sans
+\series bold
+sdcclib -?
+\begin_inset LatexCommand \index{sdcclib}
\end_inset
-\layout List
-\labelwidthstring 00.00.0000
+\newline
+\newline
-\series bold
--mmcs51
-\begin_inset LatexCommand \index{-mmcs51}
+\family default
+\series default
+To create a new library file, start by compiling all the required modules.
+ For example:
+\newline
-\end_inset
+\layout Standard
-\series default
- Generate code for the MCS51
-\begin_inset LatexCommand \index{MCS51}
+\series bold
+sdcc -c _divsint.c
+\layout Standard
-\end_inset
- family of processors.
- This is the default processor target.
-\layout List
-\labelwidthstring 00.00.0000
+\series bold
+sdcc -c _divuint.c
+\layout Standard
\series bold
--mds390
-\begin_inset LatexCommand \index{-mds390}
+sdcc -c _modsint.c
+\layout Standard
-\end_inset
+\series bold
+sdcc -c _moduint.c
+\layout Standard
-\series default
- Generate code for the DS80C390
-\begin_inset LatexCommand \index{DS80C390}
-\end_inset
+\series bold
+sdcc -c _mulint.c
+\newline
- processor.
-\layout List
-\labelwidthstring 00.00.0000
+\layout Standard
+
+This will create files _divsint.rel, _divuint.rel, _modsint.rel, _moduint.rel,
+ and _mulint.rel.
+ The next step is to add the .rel files to the library file:
+\newline
+
+\layout Standard
\series bold
--mds400
-\begin_inset LatexCommand \index{-mds400}
+sdcclib libint.lib _divsint.rel
+\begin_inset LatexCommand \index{sdcclib}
\end_inset
-\series default
- Generate code for the DS80C400
-\begin_inset LatexCommand \index{DS80C400}
+\layout Standard
-\end_inset
- processor.
-\layout List
-\labelwidthstring 00.00.0000
+\series bold
+sdcclib libint.lib _divuint.rel
+\layout Standard
\series bold
--mz80
-\begin_inset LatexCommand \index{-mz80}
+sdcclib libint.lib _modsint.rel
+\layout Standard
-\end_inset
+
+\series bold
+sdcclib libint.lib _moduint.rel
+\layout Standard
+\series bold
+sdcclib libint.lib _mulint.rel
\series default
- Generate code for the Z80
-\begin_inset LatexCommand \index{Z80}
-\end_inset
+\newline
- family of processors.
-\layout List
-\labelwidthstring 00.00.0000
+\layout Standard
+
+If the file already exists in the library, it will be replaced.
+ To see what modules and symbols are included in the library, options -s
+ and -m are available.
+ For example:
+\newline
+\newline
\series bold
--mgbz80
-\begin_inset LatexCommand \index{-mgbz80}
+sdcclib -s libint.lib
+\begin_inset LatexCommand \index{sdcclib}
\end_inset
-\series default
- Generate code for the GameBoy Z80
-\begin_inset LatexCommand \index{GameBoy Z80}
+\newline
+_divsint.rel:
+\layout Standard
-\end_inset
- processor.
-\layout List
-\labelwidthstring 00.00.0000
+\series bold
+__divsint_a_1_1
+\layout Standard
\series bold
--mavr
-\begin_inset LatexCommand \index{-mavr}
+__divsint_PARM_2
+\layout Standard
-\end_inset
+\series bold
+__divsint
+\newline
+_divuint.rel:
+\layout Standard
-\series default
- Generate code for the Atmel AVR
-\begin_inset LatexCommand \index{AVR}
-\end_inset
+\series bold
+__divuint_a_1_1
+\layout Standard
- processor (In development, not complete).
- AVR users should probably have a look at avr-gcc
-\begin_inset LatexCommand \url[FIXME: official URL?]{ http://savannah.nongnu.org/download/avr-libc/snapshots/}
-\end_inset
+\series bold
+__divuint_PARM_2
+\layout Standard
-.
-\layout Comment
-I think it is fair to direct users there for now.
- Open source is also about avoiding unnecessary work .
- But I didn't find the 'official' link.
-\layout List
-\labelwidthstring 00.00.0000
+\series bold
+__divuint_reste_1_1
+\layout Standard
\series bold
--mpic14
-\begin_inset LatexCommand \index{-mpic14}
+__divuint_count_1_1
+\layout Standard
-\end_inset
+\series bold
+__divuint
+\newline
+_modsint.rel:
+\layout Standard
-\series default
- Generate code for the PIC 14
-\begin_inset LatexCommand \index{PIC14}
-\end_inset
+\series bold
+__modsint_a_1_1
+\layout Standard
--bit processors (In development, not complete).
-\layout Comment
-p16f627 p16f628 p16f84 p16f873 p16f877?
-\layout List
-\labelwidthstring 00.00.0000
+\series bold
+__modsint_PARM_2
+\layout Standard
\series bold
--mtlcs900h
-\series default
- Generate code for the Toshiba TLCS-900H
-\begin_inset LatexCommand \index{TLCS-900H}
+__modsint
+\newline
+_moduint.rel:
+\layout Standard
-\end_inset
+
+\series bold
+__moduint_a_1_1
+\layout Standard
+
+
+\series bold
+__moduint_PARM_2
+\layout Standard
+
+
+\series bold
+__moduint_count_1_1
+\layout Standard
+
+
+\series bold
+__moduint
+\newline
+_mulint.rel:
+\layout Standard
+
+
+\series bold
+__mulint_PARM_2
+\layout Standard
+
+
+\series bold
+__mulint
+\newline
+
+\layout Standard
+
+If the source files are compiled using --debug, the corresponding debug
+ information file .adb will be include in the library file as well.
+ The library files created with sdcclib are plain text files, so they can
+ be viewed with a text editor.
+ It is not recomended to modify a library file created with sdcclib using
+ a text editor, as there are file indexes numbers located accross the file
+ used by the linker to quickly locate the required module to link.
+ Once a .rel file (as well as a .adb file) is added to a library using sdcclib,
+ it can be safely deleted, since all the information required for linking
+ is embedded in the library file itself.
+ Library files created using sdcclib are used as described in the preceding
+ sections.
+\layout Section
+
+Command Line Options
+\begin_inset LatexCommand \index{Command Line Options}
+
+\end_inset
+
+
+\layout Subsection
+
+Processor Selection Options
+\begin_inset LatexCommand \index{Options processor selection}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Processor selection options}
+
+\end_inset
+
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mmcs51
+\begin_inset LatexCommand \index{-mmcs51}
+
+\end_inset
+
+
+\series default
+ Generate code for the Intel MCS51
+\begin_inset LatexCommand \index{MCS51}
+
+\end_inset
+
+ family of processors.
+ This is the default processor target.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mds390
+\begin_inset LatexCommand \index{-mds390}
+
+\end_inset
+
+
+\series default
+ Generate code for the Dallas DS80C390
+\begin_inset LatexCommand \index{DS80C390}
+
+\end_inset
+
+ processor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mds400
+\begin_inset LatexCommand \index{-mds400}
+
+\end_inset
+
+
+\series default
+ Generate code for the Dallas DS80C400
+\begin_inset LatexCommand \index{DS80C400}
+
+\end_inset
+
+ processor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mhc08
+\begin_inset LatexCommand \index{-mhc08}
+
+\end_inset
+
+
+\series default
+ Generate code for the Motorola HC08
+\begin_inset LatexCommand \index{HC08}
+
+\end_inset
+
+ family of processors (added Oct 2003).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mz80
+\begin_inset LatexCommand \index{-mz80}
+
+\end_inset
+
+
+\series default
+ Generate code for the Zilog Z80
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ family of processors.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mgbz80
+\begin_inset LatexCommand \index{-mgbz80}
+
+\end_inset
+
+
+\series default
+ Generate code for the GameBoy Z80
+\begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
+
+\end_inset
+
+ processor (Not actively maintained).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mavr
+\begin_inset LatexCommand \index{-mavr}
+
+\end_inset
+
+
+\series default
+ Generate code for the Atmel AVR
+\begin_inset LatexCommand \index{AVR}
+
+\end_inset
processor (In development, not complete).
+ AVR users should probably have a look at avr-gcc
+\begin_inset LatexCommand \url{ http://savannah.nongnu.org/download/avr-libc/snapshots/}
+
+\end_inset
+
+.
+\layout Comment
+
+I think it is fair to direct users there for now.
+ Open source is also about avoiding unnecessary work .
+ But I didn't find the 'official' link.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mpic14
+\begin_inset LatexCommand \index{-mpic14}
+
+\end_inset
+
+
+\series default
+ Generate code for the Microchip PIC 14
+\begin_inset LatexCommand \index{PIC14}
+
+\end_inset
+
+-bit processors (p16f84 and variants.
+ In development, not complete).
+\layout Comment
+
+p16f627 p16f628 p16f84 p16f873 p16f877?
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mpic16
+\begin_inset LatexCommand \index{-mpic16}
+
+\end_inset
+
+
+\series default
+ Generate code for the Microchip PIC 16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+-bit processors (p18f452 and variants.
+ In development, not complete).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mtlcs900h
+\series default
+ Generate code for the Toshiba TLCS-900H
+\begin_inset LatexCommand \index{TLCS-900H}
+
+\end_inset
+
+ processor (Not maintained, not complete).
\layout List
\labelwidthstring 00.00.0000
\series default
- Generate code for the Philips XA51
+ Generate code for the Phillips XA51
\begin_inset LatexCommand \index{XA51}
\end_inset
- processor (In development, not complete).
-\layout Subsubsection
+ processor (Not maintained, not complete).
+\layout Subsection
Preprocessor Options
\begin_inset LatexCommand \index{Options preprocessor}
\end_inset
+\begin_inset LatexCommand \index{sdcpp (preprocessor)}
+
+\end_inset
+
+
\layout List
\labelwidthstring 00.00.0000
\series default
Command line definition of macros.
- Passed to the pre processor.
+ Passed to the preprocessor.
\layout List
\labelwidthstring 00.00.0000
'-newline if it is long.
The list of rules is printed on standard output instead of the preprocessed
C program.
- `-M' implies `-E'.
+ `-M' implies `-E
+\begin_inset LatexCommand \index{-E}
+
+\end_inset
+
+'.
\layout List
\labelwidthstring 00.00.0000
\labelwidthstring 00.00.0000
-\series bold
--Aquestion
-\series default
- (answer) Assert the answer answer for question, in case it is tested with
- a preprocessor conditional such as `#if #question(answer)'.
- `-A-' disables the standard assertions that normally describe the target
- machine.
-\layout List
-\labelwidthstring 00.00.0000
-
-
\series bold
-Umacro
\begin_inset LatexCommand \index{-Umacro}
\bar default
Like `-dD' except that the macro arguments and contents are omitted.
Only `#define name' is included in the output.
-\layout Subsubsection
+\layout List
+\labelwidthstring 00.00.0000
-Linker Options
-\begin_inset LatexCommand \index{Options linker}
+
+\series bold
+-Wp\SpecialChar ~
+preprocessorOption[,preprocessorOption]
+\series default
+
+\begin_inset LatexCommand \index{-Wp preprocessorOption[,preprocessorOption]}
\end_inset
+...
+ Pass the preprocessorOption to the preprocessor
+\family typewriter
+sdcpp
+\family default
-\begin_inset LatexCommand \index{Linker options}
+\begin_inset LatexCommand \index{sdcpp (preprocessor)}
\end_inset
+.
+ SDCC uses an adapted version of the preprocessor cpp of the GNU Compiler
+ Collection (gcc), if you need more dedicated options please refer to the
+ documentation at
+\begin_inset LatexCommand \htmlurl{http://www.gnu.org/software/gcc/onlinedocs/}
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
+.
+\layout Subsection
-\series bold
+Linker Options
+\begin_inset LatexCommand \index{Options linker}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Linker options}
+
+\end_inset
+
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
-L\SpecialChar ~
-
\series default
\series bold
-lib-path
-\begin_inset LatexCommand \index{-\/-lib-path}
+\begin_inset LatexCommand \index{-\/-lib-path <path>}
\end_inset
\end_inset
-\bar under
-
\series default
-\bar default
+\SpecialChar ~
<absolute path to additional libraries> This option is passed to the linkage
editor's additional libraries
\begin_inset LatexCommand \index{Libraries}
-xram-loc
\series default
-\begin_inset LatexCommand \index{-\/-xram-loc}
+\begin_inset LatexCommand \index{-\/-xram-loc <Value>}
\end_inset
+\SpecialChar ~
<Value> The start location of the external ram
-\begin_inset LatexCommand \index{xdata}
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
-code-loc
\series default
-\begin_inset LatexCommand \index{-\/-code-loc}
+\begin_inset LatexCommand \index{-\/-code-loc <Value>}
\end_inset
+\SpecialChar ~
<Value> The start location of the code
\begin_inset LatexCommand \index{code}
-stack-loc
\series default
-\begin_inset LatexCommand \index{-\/-stack-loc}
+\begin_inset LatexCommand \index{-\/-stack-loc <Value>}
\end_inset
+\SpecialChar ~
<Value> By default the stack
\begin_inset LatexCommand \index{stack}
-data-loc
\series default
-\begin_inset LatexCommand \index{-\/-data-loc}
+\begin_inset LatexCommand \index{-\/-data-loc <Value>}
\end_inset
+\SpecialChar ~
<Value> The start location of the internal ram data
-\begin_inset LatexCommand \index{data}
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
\end_inset
-idata-loc
\series default
-\begin_inset LatexCommand \index{-\/-idata-loc}
+\begin_inset LatexCommand \index{-\/-idata-loc <Value>}
\end_inset
+\SpecialChar ~
<Value> The start location of the indirectly addressable internal ram
-\begin_inset LatexCommand \index{idata}
+\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
\end_inset
-, default value is 0x80.
+ of the 8051, default value is 0x80.
The value entered can be in Hexadecimal or Decimal format, eg.
-
\begin_inset ERT
\labelwidthstring 00.00.0000
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-bit-loc
+\series default
+\SpecialChar ~
+<Value> The start location of the bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+ addressable internal ram of the 8051.
+ This is
+\emph on
+not
+\emph default
+ implemented yet.
+ Instead an option can be passed directly to the linker: -Wl\SpecialChar ~
+-bBSEG=<Value>.
+\layout List
+\labelwidthstring 00.00.0000
+
+
\series bold
-
\begin_inset ERT
\end_inset
- (This is the default option).
+ This is the default option.
+ The format itself is documented in the documentation of srecord
+\begin_inset LatexCommand \index{srecord (tool)}
+
+\end_inset
+
+.
\layout List
\labelwidthstring 00.00.0000
\end_inset
.
-\layout Subsubsection
+ The format itself is documented in the documentation of srecord.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-Wl\SpecialChar ~
+linkOption[,linkOption]
+\series default
+
+\begin_inset LatexCommand \index{-Wl linkOption[,linkOption]}
+
+\end_inset
+
+...
+ Pass the linkOption to the linker.
+ See file sdcc/as/doc/asxhtm.html for more on linker options.
+\layout Subsection
MCS51 Options
\begin_inset LatexCommand \index{Options MCS51}
\labelwidthstring 00.00.0000
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-small
+\begin_inset LatexCommand \index{-\/-model-small}
+
+\end_inset
+
+
+\series default
+\size large
+\emph on
+
+\size default
+\emph default
+Generate code for Small Model programs, see section Memory Models for more
+ details.
+ This is the default model.
+\layout List
+\labelwidthstring 00.00.0000
+
+
\series bold
-
\begin_inset ERT
\series default
- Generate code for Large model programs see section Memory Models for more
+ Generate code for Large model programs, see section Memory Models for more
details.
- If this option is used all source files in the project should be compiled
+ If this option is used all source files in the project have to be compiled
with this option.
- In addition the standard library routines are compiled with small model,
- they will need to be recompiled.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--model-small
-\begin_inset LatexCommand \index{-\/-model-small}
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
\end_inset
\series default
-\size large
-\emph on
-
-\size default
-\emph default
-Generate code for Small Model programs see section Memory Models for more
- details.
- This is the default model.
-\layout Subsubsection
+ Uses a pseudo stack in the first 256 bytes in the external ram for allocating
+ variables and passing parameters.
+ See section
+\begin_inset LatexCommand \ref{sub:External-Stack}
+
+\end_inset
+
+\SpecialChar ~
+ External Stack for more details.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-iram-size
+\series default
+\SpecialChar ~
+<Value>
+\begin_inset LatexCommand \index{-\/-iram-size <Value>}
+
+\end_inset
+
+ Causes the linker to check if the internal ram usage is within limits of
+ the given value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xram-size
+\series default
+\SpecialChar ~
+<Value>
+\begin_inset LatexCommand \index{-\/-xram-size <Value>}
+
+\end_inset
+
+ Causes the linker to check if the external ram usage is within limits of
+ the given value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-code-size
+\series default
+\SpecialChar ~
+<Value>
+\begin_inset LatexCommand \index{-\/-code-size <Value>}
+
+\end_inset
+
+ Causes the linker to check if the code memory usage is within limits of
+ the given value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-size
+\series default
+\SpecialChar ~
+<Value>
+\begin_inset LatexCommand \index{-\/-stack-size <Value>}
+
+\end_inset
+
+ Causes the linker to check if there is at minimum <Value> bytes for stack.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pack-iram
+\series default
+\SpecialChar ~
+
+\begin_inset LatexCommand \index{-\/-pack-iram}
+
+\end_inset
+
+ Causes the linker use unused register banks for data variables or stack.
+\layout Subsection
-DS390 Options
+DS390 / DS400 Options
\begin_inset LatexCommand \index{Options DS390}
\end_inset
\labelwidthstring 00.00.0000
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-protect-sp-update
+\begin_inset LatexCommand \index{-\/-protect-sp-update}
+
+\end_inset
+
+
+\series default
+ disable interrupts during ESP:SP updates.
+\layout List
+\labelwidthstring 00.00.0000
+
+
\series bold
-
\begin_inset ERT
-model-flat24 option
\emph default
).
-\layout Subsubsection
+\layout List
+\labelwidthstring 00.00.0000
-Optimization Options
-\begin_inset LatexCommand \index{Options optimization}
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-probe
+\begin_inset LatexCommand \index{-\/-stack-probe}
+
+\end_inset
+
+
+\series default
+ insert call to function __stack_probe at each function prologue.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-tini-libid
+\begin_inset LatexCommand \index{-\/-tini-libid}
+
+\end_inset
+
+
+\series default
+ <nnnn> LibraryID used in -mTININative.
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-use-accelerator
+\begin_inset LatexCommand \index{-\/-use-accelerator}
+
+\end_inset
+
+
+\series default
+ generate code for DS390 Arithmetic Accelerator.
+
+\layout Subsection
+
+Z80 Options
+\begin_inset LatexCommand \index{Options Z80}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Z80 options}
+
+\end_inset
+
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-callee-saves-bc
+\series default
+
+\begin_inset LatexCommand \index{-\/-callee-saves-bc}
+
+\end_inset
+
+
+\size large
+\emph on
+
+\size default
+\emph default
+Force a called function to always save BC.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-no-std-crt0
+\series default
+
+\begin_inset LatexCommand \index{-\/-no-std-crt0}
+
+\end_inset
+
+ When linking, skip the standard crt0.o object file.
+ You must provide your own crt0.o for your system when linking.
+
+\layout Subsection
+
+Optimization Options
+\begin_inset LatexCommand \index{Options optimization}
\end_inset
temporaries.
A warning message will be generated when this happens and the compiler
will indicate the number of extra bytes it allocated.
- It recommended that this option NOT be used, #pragma\SpecialChar ~
-NOGCSE
-\begin_inset LatexCommand \index{\#pragma NOGCSE}
+ It is recommended that this option NOT be used, #pragma\SpecialChar ~
+nogcse
+\begin_inset LatexCommand \index{\#pragma nogcse}
\end_inset
\series default
Will not do loop invariant optimizations, this may be turned off for reasons
explained for the previous option.
- For more details of loop optimizations performed see section Loop Invariants.It
- recommended that this option NOT be used, #pragma\SpecialChar ~
-NOINVARIANT
-\begin_inset LatexCommand \index{\#pragma NOINVARIANT}
+ For more details of loop optimizations performed see section Loop Invariants.
+ It is recommended that this option NOT be used, #pragma\SpecialChar ~
+noinvariant
+\begin_inset LatexCommand \index{\#pragma noinvariant}
\end_inset
\series default
Will not do loop induction optimizations, see section strength reduction
- for more details.It is recommended that this option is NOT used, #pragma\SpecialChar ~
-NOINDUCT
-ION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+ for more details.
+ It is recommended that this option is NOT used, #pragma\SpecialChar ~
+noinduction
+\begin_inset LatexCommand \index{\#pragma noinduction}
\end_inset
\end_inset
are implemented using jump-tables.
- See section Switch Statements for more details.
+ See section
+\begin_inset LatexCommand \ref{sub:'switch'-Statements}
+
+\end_inset
+
+\SpecialChar ~
+Switch Statements for more details.
It is recommended that this option is NOT used, #pragma\SpecialChar ~
-NOJTBOUND
-\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+nojtbound
+\begin_inset LatexCommand \index{\#pragma nojtbound}
\end_inset
\series default
- Will not memcpy initialized data in far space from code space.
+ Will not memcpy initialized data from code space into xdata space.
This saves a few bytes in code space if you don't have initialized data.
-\layout Subsubsection
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nooverlay
+\begin_inset LatexCommand \index{-\/-nooverlay}
+
+\end_inset
+
+
+\series default
+ The compiler will not overlay parameters and local variables of any function,
+ see section Parameters and local variables for more details.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-no-peep
+\begin_inset LatexCommand \index{-\/-no-peep}
+
+\end_inset
+
+
+\series default
+ Disable peep-hole optimization.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file
+\series default
+
+\begin_inset LatexCommand \index{-\/-peep-file}
+
+\end_inset
+
+\SpecialChar ~
+<filename> This option can be used to use additional rules to be used by
+ the peep hole optimizer.
+ See section
+\begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
+
+\end_inset
+
+\SpecialChar ~
+Peep Hole optimizations for details on how to write these rules.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
+
+\end_inset
+
+
+\series default
+ Pass the inline assembler code through the peep hole optimizer.
+ This can cause unexpected changes to inline assembler code, please go through
+ the peephole optimizer
+\begin_inset LatexCommand \index{Peephole optimizer}
+
+\end_inset
+
+ rules defined in the source file tree '<target>/peeph.def' before using
+ this option.
+\layout Subsection
Other Options
\begin_inset LatexCommand \index{Options other}
/
\end_inset
--xstack
-\begin_inset LatexCommand \index{-\/-xstack}
+-callee-saves
+\begin_inset LatexCommand \index{-\/-callee-saves}
\end_inset
+ function1[,function2][,function3]....
\series default
- Uses a pseudo stack in the first 256 bytes in the external ram for allocating
- variables and passing parameters.
- See section on external stack for more details.
-\layout List
-\labelwidthstring 00.00.0000
-
-
+ The compiler by default uses a caller saves convention for register saving
+ across function calls, however this can cause unnecessary register pushing
+ & popping when calling small functions from larger functions.
+ This option can be used to switch the register saving convention for the
+ function names specified.
+ The compiler will not save registers when calling these functions, no extra
+ code will be generated at the entry & exit (function prologue
\series bold
--
-\begin_inset ERT
-status Collapsed
-\layout Standard
+\begin_inset LatexCommand \index{function prologue}
-\backslash
-/
\end_inset
--callee-saves
-\begin_inset LatexCommand \index{-\/-callee-saves}
-
-\end_inset
+\series default
+ & epilogue
+\series bold
-\begin_inset LatexCommand \index{function prologue}
+\begin_inset LatexCommand \index{function epilogue}
\end_inset
- function1[,function2][,function3]....
\series default
- The compiler by default uses a caller saves convention for register saving
- across function calls, however this can cause unneccessary register pushing
- & popping when calling small functions from larger functions.
- This option can be used to switch the register saving convention for the
- function names specified.
- The compiler will not save registers when calling these functions, no extra
- code will be generated at the entry & exit for these functions to save
- & restore the registers used by these functions, this can SUBSTANTIALLY
- reduce code & improve run time performance of the generated code.
- In the future the compiler (with interprocedural analysis) will be able
+) for these functions to save & restore the registers used by these functions,
+ this can SUBSTANTIALLY reduce code & improve run time performance of the
+ generated code.
+ In the future the compiler (with inter procedural analysis) will be able
to determine the appropriate scheme to use for each function call.
DO NOT use this option for built-in functions such as _mulint..., if this
option is used for a library function the appropriate library function
-callee-saves option string.
Also see #pragma\SpecialChar ~
-CALLEE-SAVES
-\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+callee_saves
+\begin_inset LatexCommand \index{\#pragma callee\_saves}
\end_inset
\series default
\bar default
-When this option is used the compiler will generate debug information, that
- can be used with the SDCDB.
- The debug information is collected in a file with .cdb extension.
+When this option is used the compiler will generate debug information.
+ The debug information collected in a file with .cdb extension can be used
+ with the SDCDB.
For more information see documentation for SDCDB.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
-
-\backslash
-/
-\end_inset
-
--peep-file
-\series default
-
-\begin_inset LatexCommand \index{-\/-peep-file}
+ Another file with no extension contains debug information in AOMF or AOMF51
+\begin_inset LatexCommand \index{AOMF, AOMF51}
\end_inset
-<filename> This option can be used to use additional rules to be used by
- the peep hole optimizer.
- See section Peep Hole optimizations for details on how to write these rules.
+ format which is commonly used by third party tools.
\layout List
\labelwidthstring 00.00.0000
\labelwidthstring 00.00.0000
-\series bold
--Wa_asmOption[,asmOption]
-\series default
-
-\begin_inset LatexCommand \index{-Wa\_asmOption[,asmOption]}
-
-\end_inset
-
-...
- Pass the asmOption to the assembler.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
--Wl_linkOption[,linkOption]
-\series default
-
-\begin_inset LatexCommand \index{-Wl\_linkOption[,linkOption]}
-
-\end_inset
-
-...
- Pass the linkOption to the linker.
-\layout List
-\labelwidthstring 00.00.0000
-
-
\series bold
-
\begin_inset ERT
\end_inset
-\bar under
-
\series default
-\bar default
Floating point library is compiled as reentrant
\begin_inset LatexCommand \index{reentrant}
\end_inset
-.See section Installation for more details.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
-
-\backslash
-/
-\end_inset
-
--nooverlay
-\begin_inset LatexCommand \index{-\/-nooverlay}
-
-\end_inset
-
-
-\series default
- The compiler will not overlay parameters and local variables of any function,
- see section Parameters and local variables for more details.
+.
+ See section Installation for more details.
\layout List
\labelwidthstring 00.00.0000
\end_inset
function.
- The default option is to lock up i.e.
- generate a 'ljmp '.
+ The default setting is to lock up i.e.
+ generate a '
+\family typewriter
+sjmp .
+\family default
+'.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--no-peep
-\begin_inset LatexCommand \index{-\/-no-peep}
+-nostdincl
+\begin_inset LatexCommand \index{-\/-nostdincl}
\end_inset
\series default
- Disable peep-hole optimization.
+ This will prevent the compiler from passing on the default include path
+ to the preprocessor.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--peep-asm
-\begin_inset LatexCommand \index{-\/-peep-asm}
+-nostdlib
+\begin_inset LatexCommand \index{-\/-nostdlib}
\end_inset
\series default
- Pass the inline assembler code through the peep hole optimizer.
- This can cause unexpected changes to inline assembler code, please go through
- the peephole optimizer
-\begin_inset LatexCommand \index{Peephole optimizer}
+ This will prevent the compiler from passing on the default library
+\begin_inset LatexCommand \index{Libraries}
\end_inset
- rules defined in the source file tree '<target>/peeph.def' before using
- this option.
+ path to the linker.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--iram-size
-\series default
-<Value>
-\begin_inset LatexCommand \index{-\/-iram-size<Value>}
+-verbose
+\begin_inset LatexCommand \index{-\/-verbose}
\end_inset
- Causes the linker to check if the internal ram usage is within limits of
- the given value.
-\layout List
-\labelwidthstring 00.00.0000
-
-
-\series bold
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
-
-\backslash
-/
-\end_inset
--xram-size
\series default
-<Value>
-\begin_inset LatexCommand \index{-\/-xram-size<Value>}
-
-\end_inset
-
- Causes the linker to check if the external ram usage is within limits of
- the given value.
+ Shows the various actions the compiler is performing.
\layout List
\labelwidthstring 00.00.0000
\series bold
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
+-V
+\begin_inset LatexCommand \index{-V}
-\backslash
-/
\end_inset
--code-size
-\series default
-<Value>
-\begin_inset LatexCommand \index{-\/-code-size<Value>}
-
-\end_inset
- Causes the linker to check if the code usage is within limits of the given
- value.
+\series default
+ Shows the actual commands the compiler is executing.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--nostdincl
-\begin_inset LatexCommand \index{-\/-nostdincl}
+-no-c-code-in-asm
+\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
\end_inset
\series default
- This will prevent the compiler from passing on the default include path
- to the preprocessor.
+ Hides your ugly and inefficient c-code from the asm file, so you can always
+ blame the compiler :).
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--nostdlib
-\begin_inset LatexCommand \index{-\/-nostdlib}
+-i-code-in-asm
+\begin_inset LatexCommand \index{-\/-i-code-in-asm}
\end_inset
\series default
- This will prevent the compiler from passing on the default library
-\begin_inset LatexCommand \index{Libraries}
-
-\end_inset
-
- path to the linker.
+ Include i-codes in the asm file.
+ Sounds like noise but is most helpful for debugging the compiler itself.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--verbose
-\begin_inset LatexCommand \index{-\/-verbose}
+-less-pedantic
+\begin_inset LatexCommand \index{-\/-less-pedantic}
\end_inset
\series default
- Shows the various actions the compiler is performing.
-\layout List
-\labelwidthstring 00.00.0000
+ Disable some of the more pedantic warnings
+\begin_inset LatexCommand \index{Warnings}
+\end_inset
-\series bold
--V
-\begin_inset LatexCommand \index{-V}
+ (jwk burps: please be more specific here, please!).
+ If you want rather more than less warnings you should consider using a
+ separate tool dedicated to syntax checking like splint
+\begin_inset LatexCommand \url{www.splint.org}
\end_inset
-
-\series default
- Shows the actual commands the compiler is executing.
+.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--no-c-code-in-asm
-\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
+-print-search-dirs
+\begin_inset LatexCommand \index{-\/-print-search-dirs}
\end_inset
\series default
- Hides your ugly and inefficient c-code from the asm file, so you can always
- blame the compiler :).
+ Display the directories in the compiler's search path
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--i-code-in-asm
-\begin_inset LatexCommand \index{-\/-i-code-in-asm}
+-vc
+\begin_inset LatexCommand \index{-\/-vc}
\end_inset
\series default
- Include i-codes in the asm file.
- Sounds like noise but is most helpfull for debugging the compiler itself.
+ Display errors and warnings using MSVC style, so you can use SDCC with
+ visual studio.
\layout List
\labelwidthstring 00.00.0000
/
\end_inset
--less-pedantic
-\begin_inset LatexCommand \index{-\/-less-pedantic}
+-use-stdout
+\begin_inset LatexCommand \index{-\/-use-stdout}
\end_inset
\series default
- Disable some of the more pedantic warnings (jwk burps: please be more specific
- here, please!)
+ Send errors and warnings to stdout instead of stderr.
\layout List
\labelwidthstring 00.00.0000
\series bold
--
-\begin_inset ERT
-status Collapsed
+-Wa\SpecialChar ~
+asmOption[,asmOption]
+\series default
-\layout Standard
+\begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
-\backslash
-/
\end_inset
--print-search-dirs
-\begin_inset LatexCommand \index{-\/-print-search-dirs}
+...
+ Pass the asmOption to the assembler
+\begin_inset LatexCommand \index{Options assembler}
\end_inset
-\series default
- Display the directories in the compiler's search path
-\layout Subsubsection
+\begin_inset LatexCommand \index{Assembler options}
+
+\end_inset
+
+.
+ See file sdcc/as/doc/asxhtm.html for assembler options.
+\layout Subsection
Intermediate Dump Options
+\begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{Options intermediate dump}
\end_inset
) generated by the compiler in human readable form at various stages of
the compilation process.
+ More on iCodes see chapter
+\begin_inset LatexCommand \ref{sub:The-anatomy-of}
+
+\end_inset
+
+\begin_inset Quotes srd
+\end_inset
+
+The anatomy of the compiler
+\begin_inset Quotes srd
+\end_inset
+
+.
\layout List
\labelwidthstring 00.00.0000
Will cause all the above mentioned dumps to be created.
\layout Subsection
-Environment variables
-\begin_inset LatexCommand \index{Environment variables}
+Redirecting output on Windows Shells
+\layout Standard
+By default SDCC writes it's error messages to
+\begin_inset Quotes sld
\end_inset
+standard error
+\begin_inset Quotes srd
+\end_inset
-\layout Standard
-
-SDCC recognizes the following environment variables:
-\layout List
-\labelwidthstring 00.00.0000
+.
+ To force all messages to
+\begin_inset Quotes sld
+\end_inset
+standard output
+\begin_inset Quotes srd
+\end_inset
+ use
\series bold
-SDCC_LEAVE_SIGNALS
-\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
+-
+\series default
+\emph on
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
\end_inset
+\series bold
+\emph default
+-
\series default
- SDCC installs a signal handler
-\begin_inset LatexCommand \index{signal handler}
+use-stdout
+\begin_inset LatexCommand \index{-\/-use-stdout}
\end_inset
- to be able to delete temporary files after an user break (^C) or an exception.
- If this environment variable is set, SDCC won't install the signal handler
- in order to be able to debug SDCC.
+.
+ Additionally, if you happen to have visual studio installed in your windows
+ machine, you can use it to compile your sources using a custom build and
+ the SDCC -
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\emph default
+-vc
+\begin_inset LatexCommand \index{-\/-vc}
+
+\end_inset
+
+ option.
+ Something like this should work:
+\newline
+
+\newline
+
+\series bold
+c:
+\backslash
+sdcc
+\backslash
+bin
+\backslash
+sdcc.exe -
+\series default
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+\emph default
+-vc -
+\series default
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+\emph default
+-model-large -c $(InputPath)
+\layout Section
+
+Environment variables
+\begin_inset LatexCommand \index{Environment variables}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC recognizes the following environment variables:
\layout List
\labelwidthstring 00.00.0000
\series bold
-TMP
-\begin_inset LatexCommand \index{TMP}
+SDCC_LEAVE_SIGNALS
+\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
\end_inset
-,\SpecialChar ~
-TEMP
-\begin_inset LatexCommand \index{TEMP}
+
+\series default
+ SDCC installs a signal handler
+\begin_inset LatexCommand \index{signal handler}
\end_inset
-,\SpecialChar ~
+ to be able to delete temporary files after an user break (^C) or an exception.
+ If this environment variable is set, SDCC won't install the signal handler
+ in order to be able to debug SDCC.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+TMP,\SpecialChar ~
+TEMP,\SpecialChar ~
TMPDIR
-\begin_inset LatexCommand \index{TMPDIR}
+\begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
\end_inset
\series default
- Path, see
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Install-paths}
+
+\end_inset
+
+\SpecialChar ~
+
\begin_inset Quotes sld
\end_inset
-2.3 Install and search paths
+ Install Paths
\begin_inset Quotes srd
\end_inset
\series default
- Path, see
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Search-Paths}
+
+\end_inset
+
+\SpecialChar ~
+
\begin_inset Quotes sld
\end_inset
-2.3 Install and search paths
+Search Paths
\begin_inset Quotes srd
\end_inset
\series default
- Path, see
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Search-Paths}
+
+\end_inset
+
+\SpecialChar ~
+
\begin_inset Quotes sld
\end_inset
-2.3 Install and search paths
+Search Paths
\begin_inset Quotes srd
\end_inset
-.
+..
\layout Standard
There are some more environment variables recognized by SDCC, but these
are solely used for debugging purposes.
- They can change or disappear very quickly, and will never be documentated.
+ They can change or disappear very quickly, and will never be documented.
+\layout Section
+
+Storage Class Language Extensions
\layout Subsection
MCS51/DS390 Storage Class
\layout Standard
In addition to the ANSI storage classes SDCC allows the following MCS51
- specific storage classes.
+ specific storage classes:
\layout Subsubsection
-xdata
-\begin_inset LatexCommand \index{xdata}
+data
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
+
+\end_inset
+
+ / near
+\begin_inset LatexCommand \index{near (storage class)}
\end_inset
\layout Standard
-Variables declared with this storage class will be placed in the extern
- RAM.
- This is the
+This is the
\series bold
default
\series default
- storage class for Large Memory model, e.g.:
-\newline
+ storage class for the Small Memory model (
+\emph on
+data
+\emph default
+ and
+\emph on
+near
+\emph default
+ can be used synonymously).
+ Variables declared with this storage class will be allocated in the directly
+ addressable portion of the internal RAM of a 8051, e.g.:
+\layout Verse
-\newline
\family typewriter
-xdata unsigned char xduc;
+data unsigned char test_data;
+\layout Standard
+
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+75*00 01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+_test_data,#0x01
\layout Subsubsection
-data
-\begin_inset LatexCommand \index{data}
+xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
+
+\end_inset
+
+ / far
+\begin_inset LatexCommand \index{far (storage class)}
\end_inset
\layout Standard
-This is the
+Variables declared with this storage class will be placed in the external
+ RAM.
+ This is the
\series bold
default
\series default
- storage class for Small Memory model.
- Variables declared with this storage class will be allocated in the internal
- RAM, e.g.:
-\newline
+ storage class for the Large Memory model, e.g.:
+\layout Verse
-\newline
\family typewriter
-data int iramdata;
+xdata unsigned char test_xdata;
+\layout Standard
+
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+90s00r00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+dptr,#_test_xdata
+\newline
+74\SpecialChar ~
+01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+a,#0x01
+\newline
+F0\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movx\SpecialChar ~
+@dptr,a
\layout Subsubsection
idata
-\begin_inset LatexCommand \index{idata}
+\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
\end_inset
Variables declared with this storage class will be allocated into the indirectly
addressable portion of the internal ram of a 8051, e.g.:
-\newline
+\layout Verse
-\newline
\family typewriter
-idata int idi;
-\layout Subsubsection
-
-bit
-\begin_inset LatexCommand \index{bit}
+idata unsigned char test_idata;
+\layout Standard
-\end_inset
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+\family typewriter
+78r00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+r0,#_test_idata
+\newline
+76\SpecialChar ~
+01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+@r0,#0x01
\layout Standard
-This is a data-type and a storage class specifier.
- When a variable is declared as a bit, it is allocated into the bit addressable
- memory of 8051, e.g.:
-\newline
+Please note, the first 128 byte of idata physically access the same RAM
+ as the data memory.
+ The original 8051 had 128 byte idata memory, nowadays most devices have
+ 256 byte idata memory.
+ The stack
+\begin_inset LatexCommand \index{stack}
-\newline
+\end_inset
-\family typewriter
-bit iFlag;
+ is located in idata memory.
\layout Subsubsection
-sfr
-\begin_inset LatexCommand \index{sfr}
+pdata
+\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
\end_inset
- / sbit
-\begin_inset LatexCommand \index{sbit}
+
+\layout Standard
+
+Paged xdata access is currently not as straightforward as using the other
+ addressing modes of a 8051.
+ The following example writes 0x01 to the address pointed to.
+ Please note, pdata access physically accesses xdata memory.
+ The high byte of the address is determined by port P2
+\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
\end_inset
+(or in case of some 8051 variants by a separate Special Function Register,
+ see section
+\begin_inset LatexCommand \ref{sub:MCS51-variants}
-\layout Standard
+\end_inset
-Like the bit keyword,
-\emph on
-sfr / sbit
-\emph default
-signifies both a data-type and storage class, they are used to describe
- the special function registers and special bit variables of a 8051, eg:
-\newline
+).
+\layout Verse
-\newline
\family typewriter
-sfr at 0x80 P0; /* special function register P0 at location 0x80 */
+pdata unsigned char *test_pdata_ptr;
\newline
-sbit at 0xd7 CY; /* CY (Carry Flag
-\begin_inset LatexCommand \index{Flags}
-
-\end_inset
+\newline
+void main()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+test_pdata_ptr = (pdata *)0xfe;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+*test_pdata_ptr = 1;
+\newline
+}
+\layout Standard
-\begin_inset LatexCommand \index{Carry flag}
+Generates the assembly code:
+\layout Verse
-\end_inset
-) */
-\layout Subsection
+\family typewriter
+75*01 FE\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ _test_pdata_ptr,#0xFE
+\newline
+78 FE\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ r0,#0xFE
+\newline
+74 01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ a,#0x01
+\newline
+F2\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movx @r0,a
+\layout Standard
-Pointers
-\begin_inset LatexCommand \index{Pointers}
+Be extremely carefull if you use pdata together with the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+ option.
+\layout Subsubsection
+
+code
+\begin_inset LatexCommand \index{code}
+
+\end_inset
+
+
+\layout Standard
+
+'Variables' declared with this storage class will be placed in the code
+ memory:
+\layout Verse
+
+
+\family typewriter
+code unsigned char test_code;
+\layout Standard
+
+Read access to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+90s00r6F\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dptr,#_test_code
+\newline
+E4\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+clr a
+\newline
+93\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movc a,@a+dptr
+\layout Standard
+
+
+\family typewriter
+char
+\family default
+ indexed arrays of characters in code memory can be accessed efficiently:
+\layout Verse
+
+
+\family typewriter
+code char test_array[] = {'c','h','e','a','p'};
+\layout Standard
+
+Read access to this array using an 8-bit unsigned index generates the assembly
+ code:
+\layout Verse
+
+
+\family typewriter
+E5*00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,_index
+\layout Verse
+
+
+\family typewriter
+90s00r41\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dptr,#_test_array
+\layout Verse
+
+
+\family typewriter
+93\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movc a,@a+dptr
+\layout Subsubsection
+
+bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+
+\layout Standard
+
+This is a data-type and a storage class specifier.
+ When a variable is declared as a bit, it is allocated into the bit addressable
+ memory of 8051, e.g.:
+\layout Verse
+
+
+\family typewriter
+bit test_bit;
+\layout Standard
+
+Writing 1 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+D2*00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+setb\SpecialChar ~
+_test_bit
+\layout Standard
+
+The bit addressable memory consists of 128 bits which are located from 0x20
+ to 0x2f in data memory.
+
+\layout Standard
+
+Apart from this 8051 specific storage class most architectures support ANSI-C
+ bitfields
+\begin_inset LatexCommand \index{bitfields}
+
+\end_inset
+
+
+\newline
+
+\layout Standard
+
+In accordance with ISO/IEC 9899 bits and bitfields without an explicit signed
+ modifier are implemented as unsigned.
+\layout Standard
+
+
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+Not really meant as examples, but nevertheless showing what bitfields are
+ about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
+\end_inset
+
+.
+\layout Subsubsection
+
+sfr
+\begin_inset LatexCommand \index{sfr}
+
+\end_inset
+
+ / sbit
+\begin_inset LatexCommand \index{sbit}
+
+\end_inset
+
+
+\layout Standard
+
+Like the bit keyword,
+\emph on
+sfr / sbit
+\emph default
+signifies both a data-type and storage class, they are used to describe
+ the
+\emph on
+s
+\emph default
+pecial
+\emph on
+f
+\emph default
+unction
+\emph on
+r
+\emph default
+egisters and
+\emph on
+s
+\emph default
+pecial
+\emph on
+bit
+\emph default
+ variables of a 8051, eg:
+\layout Verse
+
+
+\family typewriter
+sfr at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 0x80 P0;\SpecialChar ~
+ /* special function register P0 at location 0x80 */
+\newline
+sbit at 0xd7 CY; /* CY (Carry Flag
+\begin_inset LatexCommand \index{Flags}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Carry flag}
\end_inset
+) */
+\layout Standard
+
+Special function registers which are located on an address dividable by
+ 8 are bit-addressable, an
+\emph on
+ sbit
+\emph default
+ addresses a specific bit within these sfr.
+\layout Subsubsection
+
+Pointers
+\begin_inset LatexCommand \index{Pointer}
+
+\end_inset
+ to MCS51/DS390 specific memory spaces
\layout Standard
SDCC allows (via language extensions) pointers to explicitly point to any
\newline
Pointer declaration examples:
-\newline
+\layout Verse
-\size small
+\family typewriter
+/* pointer physically in internal ram pointing to object in external ram
+ */
+\newline
+xdata unsigned char * data p;
\newline
-\family typewriter
-\size default
-/* pointer physically in xternal ram pointing to object in internal ram
+\newline
+/* pointer physically in external ram pointing to object in internal ram
*/
\newline
data unsigned char * xdata p;
\newline
\newline
-/* the folowing is a generic pointer physically located in xdata space */
+/* the following is a generic pointer physically located in xdata space
+ */
\newline
char * xdata p;
-\family default
-\size small
-
-\newline
-
-\newline
+\layout Standard
-\size default
Well you get the idea.
\newline
routines.
Explicitly specifying the pointer type will generate the most efficient
code.
-\layout Subsection
-
-Parameters
-\begin_inset LatexCommand \index{Parameters}
-
-\end_inset
+\layout Subsubsection
- & Local Variables
-\begin_inset LatexCommand \index{Local variable}
+Notes on MCS51 memory
+\begin_inset LatexCommand \index{MCS51 memory}
\end_inset
-
+ layout
\layout Standard
-Automatic (local) variables and parameters to functions can either be placed
- on the stack or in data-space.
- The default action of the compiler is to place these variables in the internal
- RAM (for small model) or external RAM (for large model).
- This in fact makes them
-\emph on
-static
-\begin_inset LatexCommand \index{static}
+The 8051 family of microcontrollers have a minimum of 128 bytes of internal
+ RAM memory which is structured as follows:
+\newline
+
+\newline
+- Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
+
+\newline
+- Bytes 20-2F - 16 bytes to hold 128 bit
+\begin_inset LatexCommand \index{bit}
\end_inset
+ variables and,
+\newline
+- Bytes 30-7F - 80 bytes for general purpose use.
+\newline
+
+\layout Standard
+Additionally some members of the MCS51 family may have up to 128 bytes of
+ additional, indirectly addressable, internal RAM memory (
+\emph on
+idata
\emph default
- so by default functions are non-reentrant
-\begin_inset LatexCommand \index{reentrant}
+
+\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
\end_inset
-.
-\newline
+).
+ Furthermore, some chips may have some built in external memory (
+\emph on
+xdata
+\emph default
-\newline
-They can be placed on the stack
-\begin_inset LatexCommand \index{stack}
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
- either by using the
+) which should not be confused with the internal, directly addressable RAM
+ memory (
\emph on
- -
-\begin_inset ERT
-status Collapsed
+data
+\emph default
-\layout Standard
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
-\backslash
-/
\end_inset
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
+).
+ Sometimes this built in
+\emph on
+xdata
+\emph default
+ memory has to be activated before using it (you can probably find this
+ information on the datasheet of the microcontroller your are using, see
+ also section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
\end_inset
+\SpecialChar ~
+Startup-Code).
+\layout Standard
-\emph default
- option or by using the
-\emph on
-reentrant
-\begin_inset LatexCommand \index{reentrant}
+Normally SDCC will only use the first bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
\end_inset
+ of registers (register bank 0), but it is possible to specify that other
+ banks of registers should be used in interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+ routines.
+ By default, the compiler will place the stack after the last byte of allocated
+ memory for variables.
+ For example, if the first 2 banks of registers are used, and only four
+ bytes are used for
+\emph on
+data
\emph default
- keyword in the function declaration, e.g.:
-\newline
+ variables, it will position the base of the internal stack at address 20
+ (0x14).
+ This implies that as the stack
+\begin_inset LatexCommand \index{stack}
-\size small
+\end_inset
-\newline
+ grows, it will use up the remaining register banks, and the 16 bytes used
+ by the 128 bit variables, and 80 bytes for general purpose use.
+ If any bit variables are used, the data variables will be placed after
+ the byte holding the last bit variable.
+ For example, if register banks 0 and 1 are used, and there are 9 bit variables
+ (two bytes used),
+\emph on
+data
+\emph default
+ variables will be placed starting at address 0x22.
+ You can also use -
+\begin_inset ERT
+status Collapsed
-\family typewriter
-\size default
-unsigned char foo(char i) reentrant
-\newline
-{
-\newline
-...
-
-\newline
-}
-\newline
+\layout Standard
-\family default
+\backslash
+/
+\end_inset
-\newline
-Since stack space on 8051 is limited, the
+-data-loc
+\begin_inset LatexCommand \index{-\/-data-loc<Value>}
+
+\end_inset
+
+ to specify the start address of the
\emph on
-reentrant
+data
\emph default
-keyword or the
-\emph on
- -
+ and -
\begin_inset ERT
status Collapsed
/
\end_inset
--stack-auto
+-iram-size to specify the size of the total internal RAM (
+\emph on
+data
\emph default
- option should be used sparingly.
- Note that the reentrant keyword just means that the parameters & local
- variables will be allocated to the stack, it
++
\emph on
-does not
+idata
\emph default
- mean that the function is register bank independent.
-\newline
-
-\newline
-Local variables can be assigned storage classes and absolute
-\begin_inset LatexCommand \index{Absolute addressing}
+).
+
+\layout Standard
-\end_inset
+By default the 8051 linker will place the stack after the last byte of data
+ variables.
+ Option -
+\begin_inset ERT
+status Collapsed
- addresses, e.g.:
-\newline
+\layout Standard
-\newline
+\backslash
+/
+\end_inset
-\family typewriter
-unsigned char foo() {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-xdata unsigned char i;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-bit bvar;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-data at 0x31 unsiged char j;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-}
-\newline
+-stack-loc
+\begin_inset LatexCommand \index{-\/-stack-loc<Value>}
-\newline
+\end_inset
-\family default
-In the above example the variable
-\emph on
-i
-\emph default
- will be allocated in the external ram,
-\emph on
-bvar
-\emph default
- in bit addressable space and
+ allows you to specify the start of the stack, i.e.
+ you could start it after any data in the general purpose area.
+ If your microcontroller has additional indirectly addressable internal
+ RAM (
\emph on
- j
+idata
\emph default
- in internal ram.
- When compiled with
-\emph on
--
+) you can place the stack on it.
+ You may also need to use -
\begin_inset ERT
status Collapsed
/
\end_inset
--stack-auto
-\emph default
- or when a function is declared as
+-xdata-loc
+\begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
+
+\end_inset
+
+ to set the start address of the external RAM (
\emph on
-reentrant
+xdata
\emph default
- this should only be done for static variables.
+) and -
+\begin_inset ERT
+status Collapsed
+
\layout Standard
-Parameters however are not allowed any storage class, (storage classes for
- parameters will be ignored), their allocation is governed by the memory
- model in use, and the reentrancy options.
-\layout Subsection
+\backslash
+/
+\end_inset
-Overlaying
-\begin_inset LatexCommand \index{Overlaying}
+-xram-size
+\begin_inset LatexCommand \index{-\/-data-loc}
\end_inset
+ to specify its size.
+ Same goes for the code memory, using -
+\begin_inset ERT
+status Collapsed
\layout Standard
-For non-reentrant
-\begin_inset LatexCommand \index{reentrant}
-
+\backslash
+/
\end_inset
- functions SDCC will try to reduce internal ram space usage by overlaying
- parameters and local variables of a function (if possible).
- Parameters and local variables of a function will be allocated to an overlayabl
-e segment if the function has
-\emph on
-no other function calls and the function is non-reentrant and the memory
- model
-\begin_inset LatexCommand \index{Memory model}
+-code-loc
+\begin_inset LatexCommand \index{-\/-data-loc}
\end_inset
- is small.
+ and -
+\begin_inset ERT
+status Collapsed
-\emph default
- If an explicit storage class
-\begin_inset LatexCommand \index{Storage class}
+\layout Standard
+\backslash
+/
\end_inset
- is specified for a local variable, it will NOT be overlayed.
+-code-size
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+.
+ If in doubt, don't specify any options and see if the resulting memory
+ layout is appropriate, then you can adjust it.
\layout Standard
-Note that the compiler (not the linkage editor) makes the decision for overlayin
-g the data items.
- Functions that are called from an interrupt service routine should be preceded
- by a #pragma\SpecialChar ~
-NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+The linker generates two files with memory allocation information.
+ The first, with extension .map
+\begin_inset LatexCommand \index{<file>.map}
\end_inset
- if they are not reentrant.
-\layout Standard
+ shows all the variables and segments.
+ The second with extension .mem
+\begin_inset LatexCommand \index{<file>.mem}
+
+\end_inset
+
+ shows the final memory layout.
+ The linker will complain either if memory segments overlap, there is not
+ enough memory, or there is not enough space for stack.
+ If you get any linking warnings and/or errors related to stack or segments
+ allocation, take a look at either the .map or .mem files to find out what
+ the problem is.
+ The .mem file may even suggest a solution to the problem.
+\layout Subsection
-Also note that the compiler does not do any processing of inline
-\begin_inset LatexCommand \index{inline}
+Z80/Z180 Storage Class
+\begin_inset LatexCommand \index{Storage class}
\end_inset
- assembler code, so the compiler might incorrectly assign local variables
- and parameters of a function into the overlay segment if the inline assembler
- code calls other c-functions that might use the overlay.
- In that case the #pragma\SpecialChar ~
-NOOVERLAY should be used.
+ Language Extensions
+\layout Subsubsection
+
+sfr
+\begin_inset LatexCommand \index{sfr}
+
+\end_inset
+
+ (in/out to 8-bit addresses)
\layout Standard
-Parameters and Local variables of functions that contain 16 or 32 bit multiplica
-tion
-\begin_inset LatexCommand \index{Multiplication}
+The Z80
+\begin_inset LatexCommand \index{Z80}
\end_inset
- or division
-\begin_inset LatexCommand \index{Division}
+ family has separate address spaces for memory and
+\emph on
+i
+\emph default
+nput/
+\emph on
+o
+\emph default
+utput memory.
+ I/O memory
+\begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
\end_inset
- will NOT be overlayed since these are implemented using external functions,
- e.g.:
-\newline
+ is accessed with special instructions, e.g.:
+\layout Verse
-\newline
\family typewriter
-#pragma SAVE
-\newline
-#pragma NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+sfr at 0x78 IoPort;\SpecialChar ~
+\SpecialChar ~
+/* define a var in I/O space at 78h called IoPort */
+
+\layout Standard
-\end_inset
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
-
-\newline
-void set_error(unsigned char errcd)
-\newline
-{
-\newline
+
+\family typewriter
+3E 01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-P3 = errcd;
-\newline
-}
-\newline
-#pragma RESTORE
+\SpecialChar ~
+ld a,#0x01
\newline
+D3 78\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+out (_IoPort),a
+\layout Subsubsection
-\newline
-void some_isr () interrupt
-\begin_inset LatexCommand \index{interrupt}
+banked sfr
+\begin_inset LatexCommand \index{sfr}
\end_inset
- 2 using
-\begin_inset LatexCommand \index{using}
+ (in/out to 16-bit addresses)
+\layout Standard
+
+The keyword
+\emph on
+banked
+\emph default
+ is used to support 16 bit addresses in I/O memory e.g.:
+\layout Verse
+
+
+\family typewriter
+sfr banked at
+\begin_inset LatexCommand \index{at}
\end_inset
- 1
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
+ 0x123 IoPort;
+\layout Standard
+
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+01 23 01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-...
+ld bc,#_IoPort
\newline
+3E 01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-set_error(10);
+\SpecialChar ~
+ld a,#0x01
\newline
+ED 79\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-...
-
-\newline
-}
-\newline
+\SpecialChar ~
+out (c),a
+\layout Subsubsection
-\newline
+sfr
+\begin_inset LatexCommand \index{sfr}
-\family default
-In the above example the parameter
-\emph on
-errcd
-\emph default
- for the function
-\emph on
-set_error
-\emph default
- would be assigned to the overlayable segment if the #pragma\SpecialChar ~
-NOOVERLAY was
- not present, this could cause unpredictable runtime behavior when called
- from an ISR.
- The #pragma\SpecialChar ~
-NOOVERLAY ensures that the parameters and local variables for
- the function are NOT overlayed.
-\layout Subsection
+\end_inset
-Interrupt Service Routines
+ (in0/out0 to 8 bit addresses on Z180
+\begin_inset LatexCommand \index{Z180}
+
+\end_inset
+
+/HD64180
+\begin_inset LatexCommand \index{HD64180}
+
+\end_inset
+
+)
\layout Standard
-SDCC allows interrupt service routines to be coded in C, with some extended
- keywords.
-\newline
+The compiler option -
+\begin_inset ERT
+status Collapsed
-\newline
+\layout Standard
-\family typewriter
-void timer_isr (void) interrupt 2 using 1
-\newline
-{
-\newline
-..
-
-\newline
-}
-\newline
+\backslash
+/
+\end_inset
-\newline
+-portmode=180 (80) and a compiler #pragma\SpecialChar ~
+portmode
+\begin_inset LatexCommand \index{\#pragma portmode}
+
+\end_inset
+=z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
+ns
+\family typewriter
+in0/out0
\family default
-The number following the
-\emph on
-interrupt
-\begin_inset LatexCommand \index{interrupt}
+ instead of
+\family typewriter
+in/out
+\family default
+.
+ If you include the file z180.h this will be set automatically.
+\layout Subsection
+
+HC08 Storage Class
+\begin_inset LatexCommand \index{Storage class}
\end_inset
+ Language Extensions
+\layout Subsubsection
-\emph default
- keyword is the interrupt number this routine will service.
- The compiler will insert a call to this routine in the interrupt vector
- table for the interrupt number specified.
- The
-\emph on
-using
-\emph default
- keyword is used to tell the compiler to use the specified register bank
- (8051 specific) when generating code for this function.
- Note that when some function is called from an interrupt service routine
- it should be preceded by a #pragma\SpecialChar ~
-NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+data
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
\end_inset
- if it is not reentrant.
- A special note here, int (16 bit) and long (32 bit) integer division
-\begin_inset LatexCommand \index{Division}
-\end_inset
+\layout Standard
-, multiplication
-\begin_inset LatexCommand \index{Multiplication}
+The data storage class declares a variable that resides in the first 256
+ bytes of memory (the direct page).
+ The HC08 is most efficient at accessing variables (especially pointers)
+ stored here.
+\layout Subsubsection
+
+xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
- & modulus
-\begin_inset LatexCommand \index{Modulus}
+
+\layout Standard
+
+The xdata storage class declares a variable that can reside anywhere in
+ memory.
+ This is the default if no storage class is specified.
+
+\layout Section
+
+Absolute Addressing
+\begin_inset LatexCommand \index{Absolute addressing}
\end_inset
- operations are implemented using external support routines developed in
- ANSI-C, if an interrupt service routine needs to do any of these operations
- then the support routines (as mentioned in a following section) will have
- to be recompiled using the
-\emph on
- -
-\begin_inset ERT
-status Collapsed
\layout Standard
-\backslash
-/
+Data items can be assigned an absolute address with the
+\emph on
+at
+\begin_inset LatexCommand \index{at}
+
\end_inset
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
+ <address>
+\emph default
+ keyword, in addition to a storage class, e.g.:
+\layout Verse
+
+
+\family typewriter
+xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
+ at
+\begin_inset LatexCommand \index{at}
-\emph default
- option and the source file will need to be compiled using the
-\emph on
--
-\begin_inset ERT
-status Collapsed
+\end_inset
+ 0x7ffe unsigned int chksum;
\layout Standard
-\backslash
-/
+In the above example the variable chksum will located at 0x7ffe and 0x7fff
+ of the external ram.
+ The compiler does
+\emph on
+not
+\emph default
+ reserve any space for variables declared in this way (they are implemented
+ with an equate in the assembler).
+ Thus it is left to the programmer to make sure there are no overlaps with
+ other variables that are declared without the absolute address.
+ The assembler listing file (.lst
+\begin_inset LatexCommand \index{<file>.lst}
+
\end_inset
--int-long-ren
-\emph default
-t
-\begin_inset LatexCommand \index{-\/-int-long-rent}
+) and the linker output files (.rst
+\begin_inset LatexCommand \index{<file>.rst}
\end_inset
- compiler option.
-\layout Standard
+) and (.map
+\begin_inset LatexCommand \index{<file>.map}
-If you have multiple source files in your project, interrupt service routines
- can be present in any of them, but a prototype of the isr MUST be present
- or included in the file that contains the function
+\end_inset
+
+) are good places to look for such overlaps.
+ Variables with an absolute address are
\emph on
-main
+not
\emph default
-.
-\layout Standard
+ initialized
+\begin_inset LatexCommand \index{Variable initialization}
-Interrupt Numbers and the corresponding address & descriptions for the Standard
- 8051 are listed below.
- SDCC will automatically adjust the interrupt vector table to the maximum
- interrupt number specified.
-\newline
+\end_inset
+.
\layout Standard
+In case of memory mapped I/O devices the keyword
+\emph on
+volatile
+\emph default
+ should be used to tell the compiler that accesses might not be optimized
+ away:
+\layout Verse
-\begin_inset Tabular
-<lyxtabular version="3" rows="6" columns="3">
-<features>
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" width="0in">
-<column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
-Interrupt #
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
-Description
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ at
+\begin_inset LatexCommand \index{at}
-Vector Address
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+ 0x8000 unsigned char PORTA_8255;
\layout Standard
-0
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
+r) array
+\family typewriter
+\size footnotesize
-\layout Standard
+\begin_inset LatexCommand \index{Aligned array}
-External 0
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
-0x0003
+\family default
+\size default
+ starts at a block (256 byte) boundary
+\begin_inset LatexCommand \index{block boundary}
+
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ (section
+\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
-1
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Timer 0
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-0x000B
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-2
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-External 1
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-0x0013
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-3
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Timer 1
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-0x001B
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-4
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-Serial
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+ has an example).
+\newline
+Absolute addresses can be specified for variables in all storage classes,
+ e.g.:
+\layout Verse
-\layout Standard
-0x0023
-\end_inset
-</cell>
-</row>
-</lyxtabular>
+\family typewriter
+bit
+\begin_inset LatexCommand \index{bit}
\end_inset
-
-\newline
-
-\newline
-If the interrupt service routine is defined without
-\emph on
-using
-\begin_inset LatexCommand \index{using}
+ at
+\begin_inset LatexCommand \index{at}
\end_inset
-
-\emph default
- a register bank or with register bank 0 (using 0), the compiler will save
- the registers used by itself on the stack upon entry and restore them at
- exit, however if such an interrupt service routine calls another function
- then the entire register bank will be saved on the stack.
- This scheme may be advantageous for small interrupt service routines which
- have low register usage.
-\layout Standard
-
-If the interrupt service routine is defined to be using a specific register
- bank then only
-\emph on
-a, b & dptr
-\emph default
- are save and restored, if such an interrupt service routine calls another
- function (using another register bank) then the entire register bank of
- the called function will be saved on the stack.
- This scheme is recommended for larger interrupt service routines.
-\layout Standard
-
-Calling other functions from an interrupt service routine is not recommended,
- avoid it if possible.
-\newline
-
-\newline
-Also see the _naked modifier.
-\layout Subsection
-
-Critical Functions
+ 0x02 bvar;
\layout Standard
+The above example will allocate the variable at offset 0x02 in the bit-addressab
+le space.
+ There is no real advantage to assigning absolute addresses to variables
+ in this manner, unless you want strict control over all the variables allocated.
+ One possible use would be to write hardware portable code.
+ For example, if you have a routine that uses one or more of the microcontroller
+ I/O pins, and such pins are different for two different hardwares, you
+ can declare the I/O pins in your routine using:
+\layout Verse
-\shape italic
-<TODO: this isn't implemented at all!>
-\shape default
-
-\newline
-
-\newline
-A special keyword may be associated with a function declaring it as
-\emph on
-critical
-\emph default
-.
- SDCC will generate code to disable all interrupts upon entry to a critical
- function and enable them back before returning.
- Note that nesting critical functions may cause unpredictable results.
-\newline
-
-\size small
-
-\newline
\family typewriter
-\size default
-int foo () critical
-\newline
-{
-\newline
-...
-
-\newline
-...
-
-\newline
-}
-\newline
-
-\family default
-
+extern volatile bit SDI;
\newline
-The critical attribute maybe used with other attributes like
-\emph on
-reentrant.
-\layout Subsection
-
-Naked Functions
-\begin_inset LatexCommand \index{Naked functions}
-
-\end_inset
-
-
-\layout Standard
-
-A special keyword may be associated with a function declaring it as
-\emph on
-_naked
-\begin_inset LatexCommand \index{\_naked}
-
-\end_inset
-
-.
-
-\emph default
-The
-\emph on
-_naked
-\emph default
- function modifier attribute prevents the compiler from generating prologue
-\begin_inset LatexCommand \index{function prologue}
-
-\end_inset
-
- and epilogue
-\begin_inset LatexCommand \index{function epilogue}
-
-\end_inset
-
- code for that function.
- This means that the user is entirely responsible for such things as saving
- any registers that may need to be preserved, selecting the proper register
- bank, generating the
-\emph on
-return
-\emph default
- instruction at the end, etc.
- Practically, this means that the contents of the function must be written
- in inline assembler.
- This is particularly useful for interrupt functions, which can have a large
- (and often unnecessary) prologue/epilogue.
- For example, compare the code generated by these two functions:
+extern volatile bit SCLK;
\newline
-
+extern volatile bit CPOL;
\newline
-\family typewriter
-data unsigned char counter;
\newline
-void simpleInterrupt(void) interrupt
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
-
- 1
+void DS1306_put(unsigned char value)
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-counter++;
-\newline
-}
+unsigned char mask=0x80;
\newline
\newline
-void nakedInterrupt(void) interrupt 2 _naked
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+while(mask)
\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
-\begin_inset LatexCommand \index{\_asm}
-
-\end_inset
-
-
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+SDI=(value & mask)?1:0;
+\newline
\SpecialChar ~
\SpecialChar ~
-inc\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_counter
+\SpecialChar ~
+\SpecialChar ~
+SCLK=!CPOL;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SCLK=CPOL;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-; MUST explicitly include ret in _naked function.
+mask/=2;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_endasm
-\begin_inset LatexCommand \index{\_endasm}
-
-\end_inset
-
-;
-\newline
}
-\family default
-
\newline
+}
+\layout Standard
-\newline
-For an 8051 target, the generated simpleInterrupt looks like:
-\newline
+Then, someplace in the code for the first hardware you would use
+\layout Verse
-\newline
\family typewriter
-_simpleIterrupt:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-acc
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dpl
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dph
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw,#0x00
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
+bit at 0x80 SDI;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-_counter
+/* I/O port 0, bit 0 */
\newline
+bit at 0x81 SCLK;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-pop\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw
+/* I/O port 0, bit 1 */
\newline
+bit CPOL;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-pop\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
-dph
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-pop\SpecialChar ~
\SpecialChar ~
+/* This is a variable, let the linker allocate this one */
+\layout Standard
+
+Similarly, for the second hardware you would use
+\layout Verse
+
+
+\family typewriter
+bit at 0x83 SDI;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-dpl
+/* I/O port 0, bit 3 */
\newline
+bit at 0x91 SCLK;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-pop\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b
+/* I/O port 1, bit 1 */
\newline
+bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+ CPOL;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-pop\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-acc
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-reti
-\family default
+/* This is a variable, let the linker allocate this one */
+\layout Standard
-\newline
+and you can use the same hardware dependent routine without changes, as
+ for example in a library.
+ This is somehow similar to sbit, but only one absolute address has to be
+ specified in the whole project.
+\layout Section
-\newline
-whereas nakedInterrupt looks like:
-\newline
+Parameters
+\begin_inset LatexCommand \index{Parameters}
-\newline
+\end_inset
-\family typewriter
-_nakedInterrupt:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-reti\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-; MUST explicitly include ret(i) in _naked function.
-\family default
-\newline
+\begin_inset LatexCommand \index{function parameter}
-\newline
-While there is nothing preventing you from writing C code inside a _naked
- function, there are many ways to shoot yourself in the foot doing this,
- and it is recommended that you stick to inline assembler.
-\layout Subsection
+\end_inset
-Functions using private banks
-\begin_inset LatexCommand \index{bank}
+ & Local Variables
+\begin_inset LatexCommand \index{local variables}
\end_inset
\layout Standard
-The
+Automatic (local) variables and parameters to functions can either be placed
+ on the stack or in data-space.
+ The default action of the compiler is to place these variables in the internal
+ RAM (for small model) or external RAM (for large model).
+ This in fact makes them similar to
\emph on
-using
-\begin_inset LatexCommand \index{using}
+static
+\begin_inset LatexCommand \index{static}
\end_inset
\emph default
- attribute (which tells the compiler to use a register bank other than the
- default bank zero) should only be applied to
-\emph on
-interrupt
-\begin_inset LatexCommand \index{interrupt}
+ so by default functions are non-reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
+.
+
+\newline
-\emph default
- functions (see note 1 below).
- This will in most circumstances make the generated ISR code more efficient
- since it will not have to save registers on the stack.
-\layout Standard
+\newline
+They can be placed on the stack
+\begin_inset LatexCommand \index{stack}
-The
-\emph on
-using
-\emph default
- attribute will have no effect on the generated code for a
+\end_inset
+
+ either by using the
\emph on
-non-interrupt
-\emph default
- function (but may occasionally be useful anyway
-\begin_inset Foot
-collapsed true
+ -
+\begin_inset ERT
+status Collapsed
\layout Standard
-possible exception: if a function is called ONLY from 'interrupt' functions
- using a particular bank, it can be declared with the same 'using' attribute
- as the calling 'interrupt' functions.
- For instance, if you have several ISRs using bank one, and all of them
- call memcpy(), it might make sense to create a specialized version of memcpy()
- 'using 1', since this would prevent the ISR from having to save bank zero
- to the stack on entry and switch to bank zero before calling the function
+\backslash
+/
\end_inset
-).
-\newline
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
-\emph on
-(pending: I don't think this has been done yet)
-\layout Standard
-An
-\emph on
-interrupt
\emph default
- function using a non-zero bank will assume that it can trash that register
- bank, and will not save it.
- Since high-priority interrupts
-\begin_inset LatexCommand \index{interrupt priority}
+ option or by using the
+\emph on
+reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
- can interrupt low-priority ones on the 8051 and friends, this means that
- if a high-priority ISR
-\emph on
-using
-\emph default
- a particular bank occurs while processing a low-priority ISR
-\emph on
-using
-\emph default
- the same bank, terrible and bad things can happen.
- To prevent this, no single register bank should be
-\emph on
-used
+
\emph default
- by both a high priority and a low priority ISR.
- This is probably most easily done by having all high priority ISRs use
- one bank and all low priority ISRs use another.
- If you have an ISR which can change priority at runtime, you're on your
- own: I suggest using the default bank zero and taking the small performance
- hit.
-\layout Standard
+ keyword in the function declaration, e.g.:
+\layout Verse
-It is most efficient if your ISR calls no other functions.
- If your ISR must call other functions, it is most efficient if those functions
- use the same bank as the ISR (see note 1 below); the next best is if the
- called functions use bank zero.
- It is very inefficient to call a function using a different, non-zero bank
- from an ISR.
-
-\layout Subsection
-
-Absolute Addressing
-\begin_inset LatexCommand \index{Absolute addressing}
-\end_inset
+\family typewriter
+unsigned char foo(char i) reentrant
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\layout Standard
+Since stack space on 8051 is limited, the
+\emph on
+reentrant
+\emph default
+keyword or the
+\emph on
+ -
+\begin_inset ERT
+status Collapsed
\layout Standard
-Data items can be assigned an absolute address with the
+\backslash
+/
+\end_inset
+
+-stack-auto
+\emph default
+ option should be used sparingly.
+ Note that the reentrant keyword just means that the parameters & local
+ variables will be allocated to the stack, it
\emph on
-at
-\begin_inset LatexCommand \index{at}
+does not
+\emph default
+ mean that the function is register bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
\end_inset
- <address>
-\emph default
- keyword, in addition to a storage class, e.g.:
+ independent.
\newline
\newline
-
-\family typewriter
-xdata
-\begin_inset LatexCommand \index{xdata}
+Local variables
+\begin_inset LatexCommand \index{local variables}
\end_inset
- at
-\begin_inset LatexCommand \index{at}
+ can be assigned storage classes and absolute
+\begin_inset LatexCommand \index{Absolute addressing}
\end_inset
- 0x8000 unsigned char PORTA_8255 ;
+ addresses, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned char foo()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+xdata unsigned char i;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+bit bvar;
\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+data at
+\begin_inset LatexCommand \index{at}
-\family default
+\end_inset
+ 0x31 unsigned char j;
\newline
-In the above example the PORTA_8255 will be allocated to the location 0x8000
- of the external ram.
- Note that this feature is provided to give the programmer access to
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\layout Standard
+
+In the above example the variable
\emph on
-memory mapped
+i
\emph default
- devices attached to the controller.
- The compiler does not actually reserve any space for variables declared
- in this way (they are implemented with an equate in the assembler).
- Thus it is left to the programmer to make sure there are no overlaps with
- other variables that are declared without the absolute address.
- The assembler listing file (.lst
-\begin_inset LatexCommand \index{.lst}
-
-\end_inset
+ will be allocated in the external ram,
+\emph on
+bvar
+\emph default
+ in bit addressable space and
+\emph on
+ j
+\emph default
+ in internal ram.
+ When compiled with
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-) and the linker output files (.rst
-\begin_inset LatexCommand \index{.rst}
+\layout Standard
+\backslash
+/
\end_inset
-) and (.map
-\begin_inset LatexCommand \index{.map}
+-stack-auto
+\emph default
+ or when a function is declared as
+\emph on
+reentrant
+\emph default
+ this should only be done for static variables.
+\layout Standard
+
+Parameters
+\begin_inset LatexCommand \index{function parameter}
\end_inset
-) are a good places to look for such overlaps.
-\newline
+ however are not allowed any storage class
+\begin_inset LatexCommand \index{Storage class}
-\newline
-Absolute address can be specified for variables in all storage classes,
- e.g.:
-\newline
+\end_inset
-\newline
+, (storage classes for parameters will be ignored), their allocation is
+ governed by the memory model in use, and the reentrancy options.
+\layout Section
-\family typewriter
-bit
-\begin_inset LatexCommand \index{bit}
+Overlaying
+\begin_inset LatexCommand \label{sub:Overlaying}
\end_inset
- at
-\begin_inset LatexCommand \index{at}
-\end_inset
+\begin_inset LatexCommand \index{Overlaying}
- 0x02 bvar;
-\newline
+\end_inset
-\newline
-\family default
-The above example will allocate the variable at offset 0x02 in the bit-addressab
-le space.
- There is no real advantage to assigning absolute addresses to variables
- in this manner, unless you want strict control over all the variables allocated.
-\layout Subsection
+\layout Standard
-Startup Code
-\begin_inset LatexCommand \index{Startup code}
+For non-reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
+ functions SDCC will try to reduce internal ram space usage by overlaying
+ parameters and local variables of a function (if possible).
+ Parameters and local variables
+\begin_inset LatexCommand \index{local variables}
-\layout Standard
+\end_inset
-The compiler inserts a call to the C routine
+ of a function will be allocated to an overlayable segment if the function
+ has
\emph on
-_sdcc_external_startup()
-\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
+no other function calls and the function is non-reentrant and the memory
+ model
+\begin_inset LatexCommand \index{Memory model}
\end_inset
+ is small.
-\series bold
\emph default
-
-\series default
-at the start of the CODE area.
- This routine is in the runtime library
-\begin_inset LatexCommand \index{Runtime library}
+ If an explicit storage class
+\begin_inset LatexCommand \index{Storage class}
\end_inset
-.
- By default this routine returns 0, if this routine returns a non-zero value,
- the static & global variable initialization will be skipped and the function
- main will be invoked Other wise static & global variables will be initialized
- before the function main is invoked.
- You could add a
-\emph on
-_sdcc_external_startup()
-\emph default
- routine to your program to override the default if you need to setup hardware
- or perform some other critical operation prior to static & global variable
- initialization.
-\layout Subsection
+ is specified for a local variable, it will NOT be overlayed.
+\layout Standard
-Inline Assembler Code
-\begin_inset LatexCommand \index{Assembler routines}
+Note that the compiler (not the linkage editor) makes the decision for overlayin
+g the data items.
+ Functions that are called from an interrupt service routine should be preceded
+ by a #pragma\SpecialChar ~
+nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
\end_inset
-
+ if they are not reentrant.
\layout Standard
-SDCC allows the use of in-line assembler with a few restriction as regards
- labels.
- All labels defined within inline assembler code
-\emph on
-has to be
-\emph default
- of the form
-\emph on
-nnnnn$
-\emph default
- where nnnn is a number less than 100 (which implies a limit of utmost 100
- inline assembler labels
-\emph on
-per function
-\emph default
-\noun on
-)
-\noun default
-.
- It is strongly recommended that each assembly instruction (including labels)
- be placed in a separate line (as the example shows).
- When the
-\emph on
--
-\begin_inset ERT
-status Collapsed
-
+Also note that the compiler does not do any processing of inline assembler
+ code, so the compiler might incorrectly assign local variables and parameters
+ of a function into the overlay segment if the inline assembler code calls
+ other c-functions that might use the overlay.
+ In that case the #pragma\SpecialChar ~
+nooverlay should be used.
\layout Standard
-\backslash
-/
-\end_inset
-
--peep-asm
-\begin_inset LatexCommand \index{-\/-peep-asm}
+Parameters and local variables of functions that contain 16 or 32 bit multiplica
+tion
+\begin_inset LatexCommand \index{Multiplication}
\end_inset
-
-\emph default
- command line option is used, the inline assembler code will be passed through
- the peephole optimizer
-\begin_inset LatexCommand \index{Peephole optimizer}
+ or division
+\begin_inset LatexCommand \index{Division}
\end_inset
-.
- This might cause some unexpected changes in the inline assembler code.
- Please go throught the peephole optimizer rules defined in file
-\emph on
-SDCCpeeph.def
-\emph default
- carefully before using this option.
-\newline
+ will NOT be overlayed since these are implemented using external functions,
+ e.g.:
+\layout Verse
-\newline
\family typewriter
-_asm
-\begin_inset LatexCommand \index{\_asm}
+#pragma save
+\newline
+#pragma nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
\end_inset
+\newline
+void set_error(unsigned char errcd)
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b,#10
-\newline
-00001$:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-djnz\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b,00001$
-\newline
-_endasm
-\begin_inset LatexCommand \index{\_endasm}
-
-\end_inset
-
- ;
-\family default
-\size small
-
+P3 = errcd;
\newline
-
+}
\newline
-
-\size default
-The inline assembler code can contain any valid code understood by the assembler
-, this includes any assembler directives and comment lines.
- The compiler does not do any validation of the code within the
-\family typewriter
-_asm ...
- _endasm;
-\family default
- keyword pair.
-
+#pragma restore
\newline
\newline
-Inline assembler code cannot reference any C-Labels, however it can reference
- labels
-\begin_inset LatexCommand \index{Labels}
+void some_isr () interrupt
+\begin_inset LatexCommand \index{interrupt}
\end_inset
- defined by the inline assembler, e.g.:
-\newline
-
-\newline
-
-\family typewriter
-foo() {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-/* some c code */
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_asm
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-; some assembler code
+ 2
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-ljmp $0003
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_endasm;
+...
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-/* some more c code */
-\newline
-clabel:\SpecialChar ~
-\SpecialChar ~
-/* inline assembler cannot reference this label */
+set_error(10);
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
+...
+
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-$0003: ;label (can be reference by inline assembler only)
+}
+\layout Standard
+
+In the above example the parameter
+\emph on
+errcd
+\emph default
+ for the function
+\emph on
+set_error
+\emph default
+ would be assigned to the overlayable segment if the #pragma\SpecialChar ~
+nooverlay was
+ not present, this could cause unpredictable runtime behavior when called
+ from an interrupt service routine.
+ The #pragma\SpecialChar ~
+nooverlay ensures that the parameters and local variables for
+ the function are NOT overlayed.
+\layout Section
+
+Interrupt Service Routines
+\begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
+
+\end_inset
+
+
+\layout Subsection
+
+General Information
+\layout Standard
+
+SDCC allows
+\emph on
+i
+\emph default
+nterrupt
+\emph on
+s
+\emph default
+ervice
+\emph on
+r
+\emph default
+outines to be coded in C, with some extended keywords.
+\layout Verse
+
+
+\family typewriter
+void timer_isr (void) interrupt 1 using 1
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_endasm ;
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-/* some more c code */
+...
+
\newline
}
-\newline
+\layout Standard
+The optional number following the
+\emph on
+interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+
+\emph default
+ keyword is the interrupt number this routine will service.
+ When present, the compiler will insert a call to this routine in the interrupt
+ vector table for the interrupt number specified.
+ If you have multiple source files in your project, interrupt service routines
+ can be present in any of them, but a prototype of the isr MUST be present
+ or included in the file that contains the function
+\emph on
+main
+\emph default
+.
+ The
+\emph on
+using
+\emph default
+ keyword can be used to tell the compiler to use the specified register
+ bank (8051 specific) when generating code for this function.
+
\newline
-\family default
-In other words inline assembly code can access labels defined in inline
- assembly within the scope of the funtion.
+\layout Standard
+
+Interrupt service routines open the door for some very interesting bugs:
\layout Standard
-The same goes the other way, ie.
- labels defines in inline assembly CANNOT be accessed by C statements.
-\layout Subsection
+If the interrupt service routines changes variables which are accessed by
+ other functions these variables should be declared
+\emph on
+volatile
+\emph default
-int (16 bit)
-\begin_inset LatexCommand \index{int (16 bit)}
+\begin_inset LatexCommand \index{volatile}
\end_inset
- and long (32 bit)
-\begin_inset LatexCommand \index{long (32 bit)}
+.
+
+\layout Standard
+
+If the access to these variables is not
+\emph on
+atomic
+\begin_inset LatexCommand \index{atomic access}
\end_inset
- Support
-\layout Standard
-For signed & unsigned int (16 bit) and long (32 bit) variables, division,
- multiplication and modulus operations are implemented by support routines.
- These support routines are all developed in ANSI-C to facilitate porting
- to other MCUs, although some model specific assembler optimations are used.
- The following files contain the described routine, all of them can be found
- in <installdir>/share/sdcc/lib.
-\newline
+\emph default
+ (i.e.
+ the processor needs more than one instruction for the access and could
+ be interrupted while accessing the variable) the interrupt must disabled
+ during the access to avoid inconsistent data.
+ Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs
+ and should be protected by disabling interrupts.
+ You're not automatically on the safe side if you use 8 bit variables though.
+ We need an example here: f.e.
+ on the 8051 the harmless looking
+\begin_inset Quotes srd
+\end_inset
-\newline
-\emph on
-<pending: tabularise this>
-\emph default
+\family typewriter
+flags\SpecialChar ~
+|=\SpecialChar ~
+0x80;
+\family default
-\newline
+\begin_inset Quotes sld
+\end_inset
-\newline
-_mulint.c - 16 bit multiplication
-\newline
-_divsint.c - signed 16 bit division (calls _divuint)
-\newline
-_divuint.c - unsigned 16 bit division
-\newline
-_modsint.c - signed 16 bit modulus (call _moduint)
-\newline
-_moduint.c - unsigned 16 bit modulus
-\newline
-_mullong.c - 32 bit multiplication
-\newline
-_divslong.c - signed 32 division (calls _divulong)
-\newline
-_divulong.c - unsigned 32 division
-\newline
-_modslong.c - signed 32 bit modulus (calls _modulong)
-\newline
-_modulong.c - unsigned 32 bit modulus
-\size footnotesize
+ is not atomic if
+\family typewriter
+flags
+\family default
+ resides in xdata.
+ Setting
+\begin_inset Quotes srd
+\end_inset
-\newline
-\newline
+\family typewriter
+flags\SpecialChar ~
+|=\SpecialChar ~
+0x40;
+\family default
-\size default
-Since they are compiled as
-\emph on
-non-reentrant
-\emph default
+\begin_inset Quotes sld
+\end_inset
-\begin_inset LatexCommand \index{reentrant}
+ from within an interrupt routine might get lost if the interrupt occurs
+ at the wrong time.
+
+\begin_inset Quotes sld
+\end_inset
+
+
+\family typewriter
+counter\SpecialChar ~
++=\SpecialChar ~
+8;
+\family default
+
+\begin_inset Quotes srd
+\end_inset
+
+ is not atomic on the 8051 even if
+\family typewriter
+counter
+\family default
+ is located in data memory.
+ Bugs like these are hard to reproduce and can cause a lot of trouble.
+
+\layout Standard
+
+A special note here, int (16 bit) and long (32 bit) integer division
+\begin_inset LatexCommand \index{Division}
\end_inset
-, interrupt
-\begin_inset LatexCommand \index{interrupt}
+, multiplication
+\begin_inset LatexCommand \index{Multiplication}
\end_inset
- service routines should not do any of the above operations.
- If this is unavoidable then the above routines will need to be compiled
- with the
+ & modulus
+\begin_inset LatexCommand \index{Modulus}
+
+\end_inset
+
+ and floating-point
+\begin_inset LatexCommand \index{Floating point support}
+
+\end_inset
+
+ operations are implemented using external support routines developed in
+ ANSI-C.
+ If an interrupt service routine needs to do any of these operations then
+ the support routines (as mentioned in a following section) will have to
+ be recompiled using the
\emph on
--
+ -
\begin_inset ERT
status Collapsed
\emph default
- option, after which the source program will have to be compiled with
+ option and the source file will need to be compiled using the
\emph on
-
\begin_inset ERT
/
\end_inset
--int-long-rent
-\begin_inset LatexCommand \index{-\/-int-long-rent}
+-int-long-reent
+\emph default
-\end_inset
-
-
-\emph default
- option.
-\layout Subsection
-
-Floating Point Support
-\begin_inset LatexCommand \index{Floating point support}
+\begin_inset LatexCommand \index{-\/-int-long-reent}
\end_inset
-
+ compiler option.
\layout Standard
-SDCC supports IEEE (single precision 4bytes) floating point numbers.The floating
- point support routines are derived from gcc's floatlib.c and consists of
- the following routines:
-\newline
-
-\newline
-
-\emph on
-<pending: tabularise this>
-\emph default
-
-\newline
+Calling other functions from an interrupt service routine is not recommended,
+ avoid it if possible.
+ Note that when some function is called from an interrupt service routine
+ it should be preceded by a #pragma\SpecialChar ~
+nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
-\newline
-_fsadd.c - add floating point numbers
-\newline
-_fssub.c - subtract floating point numbers
-\newline
-_fsdiv.c - divide floating point numbers
-\newline
-_fsmul.c - multiply floating point numbers
-\newline
-_fs2uchar.c - convert floating point to unsigned char
-\newline
-_fs2char.c - convert floating point to signed char
-\newline
-_fs2uint.c - convert floating point to unsigned int
-\newline
-_fs2int.c - convert floating point to signed int
-\newline
-_fs2ulong.c - convert floating point to unsigned long
-\newline
-_fs2long.c - convert floating point to signed long
-\newline
-_uchar2fs.c - convert unsigned char to floating point
-\newline
-_char2fs.c - convert char to floating point number
-\newline
-_uint2fs.c - convert unsigned int to floating point
-\newline
-_int2fs.c - convert int to floating point numbers
-\newline
-_ulong2fs.c - convert unsigned long to floating point number
-\newline
-_long2fs.c - convert long to floating point number
-\size footnotesize
+\end_inset
+ if it is not reentrant.
+ Furthermore nonreentrant functions should not be called from the main program
+ while the interrupt service routine might be active.
+
\newline
\newline
-
-\size default
-Note if all these routines are used simultaneously the data space might
- overflow.
- For serious floating point usage it is strongly recommended that the large
- model be used.
-\layout Subsection
-
-MCS51 Memory Models
-\begin_inset LatexCommand \index{Memory model}
+Also see section
+\begin_inset LatexCommand \ref{sub:Overlaying}
\end_inset
-
-\begin_inset LatexCommand \index{MCS51 memory}
+\SpecialChar ~
+about Overlaying and section
+\begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
\end_inset
+\SpecialChar ~
+about Functions using private register banks.
+\layout Subsection
+MCS51/DS390 Interrupt Service Routines
\layout Standard
-SDCC allows two memory models for MCS51 code, small and large.
- Modules compiled with different memory models should
-\emph on
-never
-\emph default
- be combined together or the results would be unpredictable.
- The library routines supplied with the compiler are compiled as both small
- and large.
- The compiled library modules are contained in seperate directories as small
- and large so that you can link to either set.
-
-\layout Standard
+Interrupt numbers and the corresponding address & descriptions for the Standard
+ 8051/8052 are listed below.
+ SDCC will automatically adjust the interrupt vector table to the maximum
+ interrupt number specified.
+\newline
-When the large model is used all variables declared without a storage class
- will be allocated into the external ram, this includes all parameters and
- local variables (for non-reentrant
-\begin_inset LatexCommand \index{reentrant}
+\layout Standard
+\align center
-\end_inset
+\begin_inset Tabular
+<lyxtabular version="3" rows="7" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0in">
+<column alignment="center" valignment="top" leftline="true" width="0in">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0in">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- functions).
- When the small model is used variables without storage class are allocated
- in the internal ram.
\layout Standard
-Judicious usage of the processor specific storage classes
-\begin_inset LatexCommand \index{Storage class}
-
+Interrupt #
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- and the 'reentrant' function type will yield much more efficient code,
- than using the large model.
- Several optimizations are disabled when the program is compiled using the
- large model, it is therefore strongly recommdended that the small model
- be used unless absolutely required.
-\layout Subsection
-
-DS390 Memory Models
-\begin_inset LatexCommand \index{Memory model}
+\layout Standard
+Description
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+\layout Standard
-\begin_inset LatexCommand \index{DS390 memory model}
-
+Vector Address
\end_inset
-
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-The only model supported is Flat 24
-\begin_inset LatexCommand \index{Flat 24 (memory model)}
-
+0
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-.
- This generates code for the 24 bit contiguous addressing mode of the Dallas
- DS80C390 part.
- In this mode, up to four meg of external RAM or code space can be directly
- addressed.
- See the data sheets at www.dalsemi.com for further information on this part.
-\newline
-
-\newline
-In older versions of the compiler, this option was used with the MCS51 code
- generator (
-\emph on
--mmcs51
-\emph default
-).
- Now, however, the '390 has it's own code generator, selected by the
-\emph on
--mds390
-\emph default
- switch.
-
-\newline
-
-\newline
-Note that the compiler does not generate any code to place the processor
- into 24 bitmode (although
-\emph on
-tinibios
-\emph default
- in the ds390 libraries will do that for you).
- If you don't use
-\emph on
-tinibios
-\emph default
-
-\begin_inset LatexCommand \index{Tinibios (DS390)}
+\layout Standard
+External 0
\end_inset
-
-, the boot loader or similar code must ensure that the processor is in 24
- bit contiguous addressing mode before calling the SDCC startup code.
-\newline
-
-\newline
-Like the
-\emph on
--
-\begin_inset ERT
-status Collapsed
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+0x0003
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--model-large
-\emph default
- option, variables will by default be placed into the XDATA segment.
-
-\newline
+\layout Standard
-\newline
-Segments may be placed anywhere in the 4 meg address space using the usual
- -
-\begin_inset ERT
-status Collapsed
+1
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+Timer 0
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
--*-loc options.
- Note that if any segments are located above 64K, the -r flag must be passed
- to the linker to generate the proper segment relocations, and the Intel
- HEX output format must be used.
- The -r flag can be passed to the linker by using the option
-\emph on
--Wl-r
-\emph default
- on the sdcc command line.
- However, currently the linker can not handle code segments > 64k.
-\layout Subsection
-
-Defines Created by the Compiler
-\begin_inset LatexCommand \index{Defines created by the compiler}
+\layout Standard
+0x000B
\end_inset
-
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-The compiler creates the following #defines
-\begin_inset LatexCommand \index{\#defines}
-
+2
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-.
-\layout Itemize
-
-SDCC
-\begin_inset LatexCommand \index{SDCC}
+\layout Standard
+External 1
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- - this Symbol is always defined.
-\layout Itemize
-
-SDCC_mcs51
-\begin_inset LatexCommand \index{SDCC\_mcs51}
+\layout Standard
+0x0013
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- or SDCC_ds390
-\begin_inset LatexCommand \index{SDCC\_ds390}
+\layout Standard
+3
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- or SDCC_z80
-\begin_inset LatexCommand \index{SDCC\_z80}
-
-\end_inset
-
-, etc - depending on the model used (e.g.: -mds390)
-\layout Itemize
-
-__mcs51
-\begin_inset LatexCommand \index{\_\_mcs51}
+\layout Standard
+Timer 1
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- or __ds390
-\begin_inset LatexCommand \index{\_\_ds390}
+\layout Standard
+0x001B
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- or __z80
-\begin_inset LatexCommand \index{\_\_z80}
+\layout Standard
+4
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-, etc - depending on the model used (e.g.
- -mz80)
-\layout Itemize
-
-SDCC_STACK_AUTO
-\begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
+\layout Standard
+Serial
\end_inset
-
- - this symbol is defined when
-\emph on
--
-\begin_inset ERT
-status Collapsed
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+0x0023
\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--stack-auto
-\emph default
- option is used.
-\layout Itemize
-
-SDCC_MODEL_SMALL
-\begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
+\layout Standard
+5
\end_inset
-
- - when
-\emph on
--
-\begin_inset ERT
-status Collapsed
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+Timer 2 (8052)
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
--model-small
-\emph default
- is used.
-\layout Itemize
-
-SDCC_MODEL_LARGE
-\begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
+\layout Standard
+0x002B
\end_inset
+</cell>
+</row>
+</lyxtabular>
- - when
-\emph on
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
-
-\backslash
-/
\end_inset
--model-large
-\emph default
- is used.
-\layout Itemize
-SDCC_USE_XSTACK
-\begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
+\newline
-\end_inset
+\layout Standard
- - when
+If the interrupt service routine is defined without
\emph on
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
+using
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
-\backslash
-/
\end_inset
--xstack
-\emph default
- option is used.
-\layout Itemize
-
-SDCC_STACK_TENBIT
-\begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
-
-\end_inset
- - when
+\emph default
+ a register bank or with register bank 0 (
\emph on
--mds390
+using
\emph default
- is used
-\layout Itemize
-
-SDCC_MODEL_FLAT24
-\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
-
-\end_inset
+ 0), the compiler will save the registers used by itself on the stack upon
+ entry and restore them at exit, however if such an interrupt service routine
+ calls another function then the entire register bank will be saved on the
+ stack.
+ This scheme may be advantageous for small interrupt service routines which
+ have low register usage.
+\layout Standard
- - when
+If the interrupt service routine is defined to be using a specific register
+ bank then only
\emph on
--mds390
+a, b, dptr
\emph default
- is used
-\layout Section
-\pagebreak_top
-SDCC Technical Data
+ & psw are saved and restored, if such an interrupt service routine calls
+ another function (using another register bank) then the entire register
+ bank of the called function will be saved on the stack.
+ This scheme is recommended for larger interrupt service routines.
\layout Subsection
-Optimizations
-\begin_inset LatexCommand \index{Optimizations}
-
-\end_inset
-
-
+HC08 Interrupt Service Routines
\layout Standard
-SDCC performs a host of standard optimizations in addition to some MCU specific
- optimizations.
-
-\layout Subsubsection
-
-Sub-expression Elimination
-\begin_inset LatexCommand \index{Subexpression elimination}
+Since the number of interrupts available is chip specific and the interrupt
+ vector table always ends at the last byte of memory, the interrupt numbers
+ corresponds to the interrupt vectors in reverse order of address.
+ For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
+ 2 will use the interrupt vector at 0xfffa, and so on.
+ However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
+ this way; instead see section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
\end_inset
+ for details on customizing startup.
+\layout Section
+
+Enabling and Disabling Interrupts
+\layout Subsection
+Critical Functions and Critical Statements
\layout Standard
-The compiler does local and global common subexpression elimination, e.g.:
-
-\newline
+A special keyword may be associated with a block or a function declaring
+ it as
+\emph on
+critical
+\emph default
+.
+ SDCC will generate code to disable all interrupts
+\begin_inset LatexCommand \index{interrupt}
-\newline
+\end_inset
-\family typewriter
-i = x + y + 1;
-\newline
-j = x + y;
-\family default
+ upon entry to a critical function and restore the interrupt enable to the
+ previous state before returning.
+ Nesting critical functions will need one additional byte on the stack
+\begin_inset LatexCommand \index{stack}
-\newline
+\end_inset
-\newline
-will be translated to
-\newline
+ for each call.
+\layout Verse
-\newline
\family typewriter
-iTemp = x + y
-\newline
-i = iTemp + 1
-\newline
-j = iTemp
-\newline
+int foo () critical
+\begin_inset LatexCommand \index{critical}
-\family default
+\end_inset
+
\newline
-Some subexpressions are not as obvious as the above example, e.g.:
+{
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
\newline
-
-\family typewriter
-a->b[i].c = 10;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
\newline
-a->b[i].d = 11;
-\family default
+}
+\layout Standard
-\newline
+The critical attribute maybe used with other attributes like
+\emph on
+reentrant.
+\emph default
\newline
-In this case the address arithmetic a->b[i] will be computed only once;
- the equivalent code in C would be.
-\newline
+The keyword
+\emph on
+critical
+\emph default
+ may also be used to disable interrupts more locally:
+\layout Verse
-\newline
\family typewriter
-iTemp = a->b[i];
-\newline
-iTemp.c = 10;
-\newline
-iTemp.d = 11;
-\family default
+critical{ i++; }
+\layout Standard
-\newline
+More than one statement could have been included in the block.
+\layout Subsection
-\newline
-The compiler will try to keep these temporary variables in registers.
-\layout Subsubsection
+Enabling and Disabling Interrupts directly
+\layout Standard
-Dead-Code Elimination
-\begin_inset LatexCommand \index{Dead-code elimination}
+Interrupts
+\begin_inset LatexCommand \index{interrupt}
\end_inset
-
-\layout Standard
+ can also be disabled and enabled directly (8051):
+\layout Verse
\family typewriter
-int global;
-\newline
-void f () {
-\newline
+EA = 0;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-int i;
-\newline
\SpecialChar ~
\SpecialChar ~
-i = 1; \SpecialChar ~
-/* dead store */
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 1;\SpecialChar ~
-/* dead store */
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 2;
-\newline
\SpecialChar ~
\SpecialChar ~
-return;
-\newline
\SpecialChar ~
+or:\SpecialChar ~
\SpecialChar ~
-global = 3;\SpecialChar ~
-/* unreachable */
-\newline
-}
-\family default
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+EA_SAVE = EA;
+\layout Verse
-\newline
-
-\newline
-will be changed to
-\newline
-
-\newline
\family typewriter
-int global; void f ()
-\newline
-{
-\newline
+...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-global = 2;
-\newline
\SpecialChar ~
\SpecialChar ~
-return;
-\newline
-}
-\layout Subsubsection
-
-Copy-Propagation
-\begin_inset LatexCommand \index{Copy propagation}
-
-\end_inset
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+EA = 0;
+\layout Verse
-\layout Standard
+\family typewriter
+EA = 1;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+\layout Verse
\family typewriter
-int f() {
-\newline
\SpecialChar ~
\SpecialChar ~
-int i, j;
-\newline
\SpecialChar ~
\SpecialChar ~
-i = 10;
-\newline
\SpecialChar ~
\SpecialChar ~
-j = i;
-\newline
\SpecialChar ~
\SpecialChar ~
-return j;
-\newline
-}
-\family default
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+EA = EA_SAVE;
+\layout Standard
-\newline
+On other architectures which have seperate opcodes for enabling and disabling
+ interrupts you might want to make use of defines with inline assembly
+\begin_inset LatexCommand \index{Assembler routines}
-\newline
-will be changed to
-\newline
+\end_inset
+
+ (HC08):
+\layout Verse
-\newline
\family typewriter
-int f() {
-\newline
-\SpecialChar ~
- \SpecialChar ~
- int i,j;
-\newline
+#define CLI _asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
\SpecialChar ~
- \SpecialChar ~
- i = 10;
-\newline
\SpecialChar ~
- \SpecialChar ~
- j = 10;
-\newline
+cli\SpecialChar ~
\SpecialChar ~
- \SpecialChar ~
- return 10;
-\newline
-}
-\newline
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
-\newline
+\end_inset
-\family default
-Note: the dead stores created by this copy propagation will be eliminated
- by dead-code elimination.
-\layout Subsubsection
+;
+\layout Verse
-Loop Optimizations
-\begin_inset LatexCommand \index{Loop optimization}
-\end_inset
+\family typewriter
+#define SEI _asm\SpecialChar ~
+\SpecialChar ~
+sei\SpecialChar ~
+\SpecialChar ~
+_endasm;
+\layout Verse
+\family typewriter
+...
\layout Standard
-Two types of loop optimizations are done by SDCC loop invariant lifting
- and strength reduction of loop induction variables.
- In addition to the strength reduction the optimizer marks the induction
- variables and the register allocator tries to keep the induction variables
- in registers for the duration of the loop.
- Because of this preference of the register allocator
-\begin_inset LatexCommand \index{Register allocation}
-
-\end_inset
-
-, loop induction optimization causes an increase in register pressure, which
- may cause unwanted spilling of other temporary variables into the stack
-\begin_inset LatexCommand \index{stack}
+Note: it is sometimes sufficient to disable only a specific interrupt source
+ like f.e.
+ a timer or serial interrupt by manipulating an
+\emph on
+interrupt mask
+\begin_inset LatexCommand \index{interrupt mask}
\end_inset
- / data space.
- The compiler will generate a warning message when it is forced to allocate
- extra space either on the stack or data space.
- If this extra space allocation is undesirable then induction optimization
- can be eliminated either for the entire source file (with -
-\begin_inset ERT
-status Collapsed
+\emph default
+ register.
+
\layout Standard
-\backslash
-/
-\end_inset
+Usually the time during which interrupts are disabled should be kept as
+ short as possible.
+ This minimizes both
+\emph on
+interrupt latency
+\emph default
--noinduction option) or for a given function only using #pragma\SpecialChar ~
-NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+\begin_inset LatexCommand \index{interrupt latency}
\end_inset
-.
-\newline
+ (the time between the occurrence of the interrupt and the execution of
+ the first code in the interrupt routine) and
+\emph on
+interrupt jitter
+\emph default
-\newline
-Loop Invariant:
-\newline
+\begin_inset LatexCommand \index{interrupt jitter}
-\newline
+\end_inset
-\family typewriter
-for (i = 0 ; i < 100 ; i ++)
-\newline
- \SpecialChar ~
- \SpecialChar ~
-f += k + l;
-\family default
+ (the difference between the shortest and the longest interrupt latency).
+ These really are something different, f.e.
+ a serial interrupt has to be served before its buffer overruns so it cares
+ for the maximum interrupt latency, whereas it does not care about jitter.
+ On a loudspeaker driven via a digital to analog converter which is fed
+ by an interrupt a latency of a few milliseconds might be tolerable, whereas
+ a much smaller jitter will be very audible.
+\layout Standard
-\newline
+You can reenable interrupts within an interrupt routine and on some architecture
+s you can make use of two (or more) levels of
+\emph on
+interrupt priorities
+\emph default
-\newline
-changed to
-\newline
+\begin_inset LatexCommand \index{interrupt priority}
-\newline
+\end_inset
-\family typewriter
-itemp = k + l;
-\newline
-for (i = 0; i < 100; i++)
-\newline
-\SpecialChar ~
-\SpecialChar ~
-f += itemp;
-\family default
+.
+ On some architectures which don't support interrupt priorities these can
+ be implemented by manipulating the interrupt mask and reenabling interrupts
+ within the interrupt routine.
+ Don't add complexity unless you have to.
+
+\layout Section
-\newline
+Functions using private register banks
+\begin_inset LatexCommand \label{sub:Functions-using-private-banks}
-\newline
-As mentioned previously some loop invariants are not as apparent, all static
- address computations are also moved out of the loop.
-\newline
+\end_inset
-\newline
-Strength Reduction
-\begin_inset LatexCommand \index{Strength reduction}
+ (mcs51/ds390)
+\layout Standard
+
+Some architectures have support for quickly changing register sets.
+ SDCC supports this feature with the
+\emph on
+using
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
\end_inset
-, this optimization substitutes an expression by a cheaper expression:
-\newline
-\newline
+\emph default
+ attribute (which tells the compiler to use a register bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
-\family typewriter
-for (i=0;i < 100; i++)
-\newline
-\SpecialChar ~
-\SpecialChar ~
-ar[i*5] = i*3;
-\family default
+\end_inset
-\newline
+ other than the default bank zero).
+ It should only be applied to
+\emph on
+interrupt
+\begin_inset LatexCommand \index{interrupt}
-\newline
-changed to
-\newline
+\end_inset
-\newline
-\family typewriter
-itemp1 = 0;
-\newline
-itemp2 = 0;
-\newline
-for (i=0;i< 100;i++) {
-\newline
- \SpecialChar ~
- \SpecialChar ~
-ar[itemp1] = itemp2;
-\newline
- \SpecialChar ~
- \SpecialChar ~
-itemp1 += 5;
-\newline
- \SpecialChar ~
- \SpecialChar ~
-itemp2 += 3;
-\newline
-}
-\family default
+\emph default
+ functions (see footnote below).
+ This will in most circumstances make the generated ISR code more efficient
+ since it will not have to save registers on the stack.
+\layout Standard
-\newline
+The
+\emph on
+using
+\emph default
+ attribute will have no effect on the generated code for a
+\emph on
+non-interrupt
+\emph default
+ function (but may occasionally be useful anyway
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+possible exception: if a function is called ONLY from 'interrupt' functions
+ using a particular bank, it can be declared with the same 'using' attribute
+ as the calling 'interrupt' functions.
+ For instance, if you have several ISRs using bank one, and all of them
+ call memcpy(), it might make sense to create a specialized version of memcpy()
+ 'using 1', since this would prevent the ISR from having to save bank zero
+ to the stack on entry and switch to bank zero before calling the function
+\end_inset
+).
\newline
-The more expensive multiplication
-\begin_inset LatexCommand \index{Multiplication}
+
+\emph on
+(pending: I don't think this has been done yet)
+\layout Standard
+
+An
+\emph on
+interrupt
+\emph default
+ function using a non-zero bank will assume that it can trash that register
+ bank, and will not save it.
+ Since high-priority interrupts
+\begin_inset LatexCommand \index{interrupt priority}
\end_inset
- is changed to a less expensive addition.
-\layout Subsubsection
+ can interrupt low-priority ones on the 8051 and friends, this means that
+ if a high-priority ISR
+\emph on
+using
+\emph default
+ a particular bank occurs while processing a low-priority ISR
+\emph on
+using
+\emph default
+ the same bank, terrible and bad things can happen.
+ To prevent this, no single register bank should be
+\emph on
+used
+\emph default
+ by both a high priority and a low priority ISR.
+ This is probably most easily done by having all high priority ISRs use
+ one bank and all low priority ISRs use another.
+ If you have an ISR which can change priority at runtime, you're on your
+ own: I suggest using the default bank zero and taking the small performance
+ hit.
+\layout Standard
-Loop Reversing
-\begin_inset LatexCommand \index{Loop reversing}
+It is most efficient if your ISR calls no other functions.
+ If your ISR must call other functions, it is most efficient if those functions
+ use the same bank as the ISR (see note 1 below); the next best is if the
+ called functions use bank zero.
+ It is very inefficient to call a function using a different, non-zero bank
+ from an ISR.
+
+\layout Section
+
+Startup Code
+\begin_inset LatexCommand \label{sub:Startup-Code}
\end_inset
-\layout Standard
+\begin_inset LatexCommand \index{Startup code}
-This optimization is done to reduce the overhead of checking loop boundaries
- for every iteration.
- Some simple loops can be reversed and implemented using a
-\begin_inset Quotes eld
\end_inset
-decrement and jump if not zero
-\begin_inset Quotes erd
+
+\layout Subsection
+
+MCS51/DS390 Startup Code
+\layout Standard
+
+The compiler inserts a call to the C routine
+\emph on
+_sdcc_external_startup()
+\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
+
\end_inset
- instruction.
- SDCC checks for the following criterion to determine if a loop is reversible
- (note: more sophisticated compilers use data-dependency analysis to make
- this determination, SDCC uses a more simple minded analysis).
-\layout Itemize
-The 'for' loop is of the form
-\newline
+\series bold
+\emph default
+
+\series default
+at the start of the CODE area.
+ This routine is in the runtime library
+\begin_inset LatexCommand \index{Runtime library}
-\newline
+\end_inset
-\family typewriter
-for (<symbol> = <expression> ; <sym> [< | <=] <expression> ; [<sym>++ |
- <sym> += 1])
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-<for body>
-\layout Itemize
+.
+ By default this routine returns 0, if this routine returns a non-zero value,
+ the static & global variable initialization will be skipped and the function
+ main will be invoked.
+ Otherwise static & global variables will be initialized before the function
+ main is invoked.
+ You could add a
+\emph on
+_sdcc_external_startup()
+\emph default
+ routine to your program to override the default if you need to setup hardware
+ or perform some other critical operation prior to static & global variable
+ initialization.
+ On some mcs51 variants xdata has to be explicitly enabled before it can
+ be accessed, this is the place to do it.
+ See also the compiler option
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-The <for body> does not contain
-\begin_inset Quotes eld
+\layout Standard
+
+\backslash
+/
\end_inset
-continue
-\begin_inset Quotes erd
+-no-xinit
+\emph default
+-
+\emph on
+opt
+\emph default
+
+\begin_inset LatexCommand \index{-\/-no-xinit-opt}
+
\end_inset
- or 'break
-\begin_inset Quotes erd
+ and section
+\begin_inset LatexCommand \ref{sub:MCS51-variants}
+
\end_inset
-.
-\layout Itemize
+\SpecialChar ~
+about MCS51-variants.
+\layout Subsection
-All goto's are contained within the loop.
-\layout Itemize
+HC08 Startup Code
+\layout Standard
-No function calls within the loop.
-\layout Itemize
+The HC08 startup code follows the same scheme as the MCS51 startup code.
+\layout Subsection
-The loop control variable <sym> is not assigned any value within the loop
-\layout Itemize
+Z80 Startup Code
+\layout Standard
-The loop control variable does NOT participate in any arithmetic operation
- within the loop.
-\layout Itemize
+On the Z80 the startup code is inserted by linking with crt0.o which is generated
+ from sdcc/device/lib/z80/crt0.s.
+ If you need a different startup code you can use the compiler option
+\emph on
+-
+\series bold
+\emph default
-There are NO switch statements in the loop.
-\layout Subsubsection
+\begin_inset ERT
+status Collapsed
-Algebraic Simplifications
\layout Standard
-SDCC does numerous algebraic simplifications, the following is a small sub-set
- of these optimizations.
-\newline
+\backslash
+/
+\end_inset
-\newline
-\family typewriter
-i = j + 0 ; /* changed to */ i = j;
-\newline
-i /= 2; /* changed to */ i >>= 1;
-\newline
-i = j - j ; /* changed to */ i = 0;
-\newline
-i = j / 1 ; /* changed to */ i = j;
-\family default
+\series default
+\emph on
+-no-std-crt0
+\emph default
-\newline
+\begin_inset LatexCommand \index{-\/-no-std-crt0}
-\newline
-Note the subexpressions
-\begin_inset LatexCommand \index{Subexpression}
+\end_inset
+
+ and provide your own crt0.o.
+
+\layout Section
+
+Inline Assembler Code
+\begin_inset LatexCommand \index{Assembler routines}
\end_inset
- given above are generally introduced by macro expansions or as a result
- of copy/constant propagation.
-\layout Subsubsection
-'switch' Statements
-\begin_inset LatexCommand \index{switch statement}
+\layout Subsection
+
+A Step by Step Introduction
+\begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}
\end_inset
\layout Standard
-SDCC changes switch statements to jump tables
-\begin_inset LatexCommand \index{jump tables}
+Starting from a small snippet of c-code this example shows for the MCS51
+ how to use inline assembly, access variables, a function parameter and
+ an array in xdata memory.
+ The example uses an MCS51 here but is easily adapted for other architectures.
+ This is a buffer routine which should be optimized:
+\layout Verse
+
+
+\family typewriter
+\size footnotesize
+unsigned char far
+\begin_inset LatexCommand \index{far (storage class)}
\end_inset
- when the following conditions are true.
-
-\layout Itemize
+ at
+\begin_inset LatexCommand \index{at}
-The case labels are in numerical sequence, the labels need not be in order,
- and the starting number need not be one or zero.
-\newline
+\end_inset
+
+ 0x7f00 buf[0x100];
+\begin_inset LatexCommand \index{Aligned array}
+
+\end_inset
+
+\newline
+unsigned char head,tail;
\newline
-\family typewriter
-switch(i) {\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-switch (i) {
-\newline
-case 4:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 1: ...
-
-\newline
-case 5:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 2: ...
-
\newline
-case 3:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 3: ...
-
+void to_buffer( unsigned char c )
\newline
-case 6:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 4: ...
-
+{
\newline
-}\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-}
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+if( head != tail-1 )
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+buf[ head++ ] = c;
\newline
+}
+\layout Standard
+If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
+ then a corresponding buffer.asm file is generated.
+ We define a new function
+\family typewriter
+to_buffer_asm()
\family default
-Both the above switch statements will be implemented using a jump-table.
-\layout Itemize
+ in file buffer.c in which we cut and paste the generated code, removing
+ unwanted comments and some ':'.
+ Then add
+\begin_inset Quotes sld
+\end_inset
-The number of case labels is at least three, since it takes two conditional
- statements to handle the boundary conditions.
-\layout Itemize
+_asm
+\begin_inset Quotes srd
+\end_inset
-The number of case labels is less than 84, since each label takes 3 bytes
- and a jump-table can be utmost 256 bytes long.
-
-\layout Standard
+ and
+\begin_inset Quotes sld
+\end_inset
-Switch statements which have gaps in the numeric sequence or those that
- have more that 84 case labels can be split into more than one switch statement
- for efficient code generation, e.g.:
-\newline
+_endasm;
+\begin_inset Quotes srd
+\end_inset
+
+ to the beginning and the end of the function body:
+\layout Verse
-\newline
\family typewriter
-switch (i) {
-\newline
-case 1: ...
-
-\newline
-case 2: ...
-
-\newline
-case 3: ...
-
-\newline
-case 4: ...
-
-\newline
-case 9: ...
-
+\size footnotesize
+/* With a cut and paste from the .asm file, we have something to start with.
\newline
-case 10: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+The function is not yet OK! (registers aren't saved) */
\newline
-case 11: ...
-
+void to_buffer_asm( unsigned char c )
\newline
-case 12: ...
-
+{
\newline
-}
-\family default
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
-\newline
\newline
-If the above switch statement is broken down into two switch statements
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+r2,dpl
\newline
-
+;buffer.c if( head != tail-1 )
\newline
-
-\family typewriter
-switch (i) {
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+a,_tail
\newline
-case 1: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dec\SpecialChar ~
+\SpecialChar ~
+a
\newline
-case 2: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+r3,a
\newline
-case 3: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+a,_head
\newline
-case 4: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+cjne a,ar3,00106$
\newline
-}
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ret
\newline
-
+00106$:
\newline
+;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
+\begin_inset LatexCommand \index{Aligned array}
-\family default
-and
-\family typewriter
+\end_inset
-\newline
\newline
-switch (i) {
-\newline
-case 9: \SpecialChar ~
-...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+r3,_head
\newline
-case 10: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+_head
\newline
-case 11: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+dpl,r3
\newline
-case 12:\SpecialChar ~
-...
-
-\newline
-}
-\newline
-
-\newline
-
-\family default
-then both the switch statements will be implemented using jump-tables whereas
- the unmodified switch statement will not be.
-\layout Subsubsection
-
-Bit-shifting Operations
-\begin_inset LatexCommand \index{Bit shifting}
-
-\end_inset
-
-.
-\layout Standard
-
-Bit shifting is one of the most frequently used operation in embedded programmin
-g.
- SDCC tries to implement bit-shift operations in the most efficient way
- possible, e.g.:
-\newline
-
-\family typewriter
-
-\newline
-unsigned char i;
-\newline
-...
-
-\newline
-i>>= 4;
-\newline
-...
-\newline
-
-\family default
-
-\newline
-generates the following code:
-\newline
-
-\family typewriter
-
-\newline
-mov a,_i
-\newline
-swap a
-\newline
-anl a,#0x0f
-\newline
-mov _i,a
-\family default
-
-\newline
-
-\newline
-In general SDCC will never setup a loop if the shift count is known.
- Another example:
-\newline
-
-\newline
-
-\family typewriter
-unsigned int i;
-\newline
-...
-
-\newline
-i >>= 9;
-\newline
-...
-\family default
-
-\newline
-
-\newline
-will generate:
-\newline
-
-\newline
-
-\family typewriter
-mov a,(_i + 1)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+dph,#(_buf >> 8)
\newline
-mov (_i + 1),#0x00
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+a,r2
\newline
-clr c
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movx @dptr,a
\newline
-rrc a
+00103$:
\newline
-mov _i,a
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ret
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm;
\newline
-Note that SDCC stores numbers in little-endian format (i.e.
- lowest order first).
-\layout Subsubsection
-
-Bit-rotation
-\begin_inset LatexCommand \index{Bit rotation}
-
-\end_inset
-
-
+}
\layout Standard
-A special case of the bit-shift operation is bit rotation, SDCC recognizes
- the following expression to be a left bit-rotation:
-\newline
-
-\newline
-
-\family typewriter
-unsigned char i;
-\newline
-...
-
-\newline
-i = ((i << 1) | (i >> 7));
-\family default
-
-\newline
-...
-\newline
-
-\newline
-will generate the following code:
-\newline
+The new file buffer.c should compile with only one warning about the unreferenced
+ function argument 'c'.
+ Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
+ (1) and finally have:
+\layout Verse
-\newline
\family typewriter
-mov a,_i
-\newline
-rl a
-\newline
-mov _i,a
-\family default
-
-\newline
-
-\newline
-SDCC uses pattern matching on the parse tree to determine this operation.Variatio
-ns of this case will also be recognized as bit-rotation, i.e.:
+\size footnotesize
+unsigned char far at 0x7f00 buf[0x100];
\newline
-
+unsigned char head,tail;
\newline
-
-\family typewriter
-i = ((i >> 7) | (i << 1)); /* left-bit rotation */
-\layout Subsubsection
-
-Highest Order Bit
-\begin_inset LatexCommand \index{Highest Order Bit}
-
-\end_inset
-
-
-\layout Standard
-
-It is frequently required to obtain the highest order bit of an integral
- type (long, int, short or char types).
- SDCC recognizes the following expression to yield the highest order bit
- and generates optimized code for it, e.g.:
+#define USE_ASSEMBLY (1)
\newline
\newline
-
-\family typewriter
-unsigned int gint;
+#if !USE_ASSEMBLY
\newline
\newline
-foo () {
+void to_buffer( unsigned char c )
\newline
-unsigned char hob;
+{
\newline
\SpecialChar ~
\SpecialChar ~
-...
-
-\newline
\SpecialChar ~
\SpecialChar ~
-hob = (gint >> 15) & 1;
+if( head != tail-1 )
\newline
\SpecialChar ~
\SpecialChar ~
-..
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+buf[ head++ ] = c;
\newline
}
-\family default
-
\newline
\newline
-will generate the following code:
+#else
\newline
-\family typewriter
-
+\newline
+void to_buffer( unsigned char c )
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+c; // to avoid warning: unreferenced function argument
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+; save used registers here.
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 61 ;\SpecialChar ~
- hob.c 7
+; If we were still using r2,r3 we would have to push them here.
+
+\newline
+; if( head != tail-1 )
\newline
\SpecialChar ~
\SpecialChar ~
- 000A E5*01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov\SpecialChar ~
+ a,_tail
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- 62\SpecialChar ~
+dec\SpecialChar ~
+ a
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- a,(_gint + 1)
-\newline
\SpecialChar ~
+xrl\SpecialChar ~
+ a,_head
+\newline
\SpecialChar ~
- 000C 33\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+; we could do an ANL a,#0x0f here to use a smaller buffer (see below)
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+jz\SpecialChar ~
\SpecialChar ~
+ t_b_end$
+\newline
\SpecialChar ~
- 63\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- rlc\SpecialChar ~
- a
+;
+\newline
+; buf[ head++ ] = c;
\newline
-\SpecialChar ~
-\SpecialChar ~
- 000D E4\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov\SpecialChar ~
+ a,dpl \SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+; dpl holds lower byte of function argument
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- 64\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov\SpecialChar ~
+ dpl,_head \SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- clr\SpecialChar ~
- a
+; buf is 0x100 byte aligned so head can be used directly
\newline
\SpecialChar ~
-\SpecialChar ~
- 000E 13\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov\SpecialChar ~
+ dph,#(_buf>>8)
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+movx @dptr,a
+\newline
\SpecialChar ~
- 65\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- rrc\SpecialChar ~
- a
+inc \SpecialChar ~
+_head
\newline
\SpecialChar ~
-\SpecialChar ~
- 000F F5*02\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+; we could do an ANL _head,#0x0f here to use a smaller buffer (see above)
+\newline
+t_b_end$:
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- 66\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+; restore used registers here
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- _foo_hob_1_1,a
+_endasm;
\newline
-
+}
\newline
+#endif
+\layout Standard
-\family default
-Variations of this case however will
-\emph on
-not
-\emph default
- be recognized.
- It is a standard C expression, so I heartily recommend this be the only
- way to get the highest order bit, (it is portable).
- Of course it will be recognized even if it is embedded in other expressions,
- e.g.:
-\newline
+The inline assembler code can contain any valid code understood by the assembler
+, this includes any assembler directives and comment lines
+\begin_inset Foot
+collapsed false
-\newline
+\layout Standard
+
+The assembler does not like some characters like ':' or ''' in comments.
+ You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
+\end_inset
+.
+ The compiler does not do any validation of the code within the
\family typewriter
-xyz = gint + ((gint >> 15) & 1);
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+ ...
+ _endasm;
\family default
+ keyword pair.
+ Specifically it will not know which registers are used and thus register
+ pushing/popping
+\begin_inset LatexCommand \index{push/pop}
-\newline
+\end_inset
-\newline
-will still be recognized.
-\layout Subsubsection
+ has to be done manually.
+
+\layout Standard
-Peephole Optimizer
+It is recommended that each assembly instruction (including labels) be placed
+ in a separate line (as the example shows).
+ When the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-
+\emph on
+peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
+
+\end_inset
+
+
+\emph default
+ command line option is used, the inline assembler code will be passed through
+ the peephole optimizer
\begin_inset LatexCommand \index{Peephole optimizer}
\end_inset
+.
+ There are only a few (if any) cases where this option makes sense, it might
+ cause some unexpected changes in the inline assembler code.
+ Please go through the peephole optimizer rules defined in file
+\emph on
+SDCCpeeph.def
+\emph default
+ before using this option.
+\layout Subsection
+
+Naked Functions
+\begin_inset LatexCommand \label{sub:Naked-Functions}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Naked functions}
+
+\end_inset
+
\layout Standard
-The compiler uses a rule based, pattern matching and re-writing mechanism
- for peep-hole optimization.
- It is inspired by
+A special keyword may be associated with a function declaring it as
\emph on
-copt
+_naked
+\begin_inset LatexCommand \index{\_naked}
+
+\end_inset
+
+.
+
\emph default
- a peep-hole optimizer by Christopher W.
- Fraser (cwfraser@microsoft.com).
- A default set of rules are compiled into the compiler, additional rules
- may be added with the
+The
\emph on
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
+_naked
+\emph default
+ function modifier attribute prevents the compiler from generating prologue
+\begin_inset LatexCommand \index{function prologue}
-\backslash
-/
\end_inset
--peep-file
-\begin_inset LatexCommand \index{-\/-peep-file}
+ and epilogue
+\begin_inset LatexCommand \index{function epilogue}
\end_inset
- <filename>
+ code for that function.
+ This means that the user is entirely responsible for such things as saving
+ any registers that may need to be preserved, selecting the proper register
+ bank, generating the
+\emph on
+return
\emph default
- option.
- The rule language is best illustrated with examples.
+ instruction at the end, etc.
+ Practically, this means that the contents of the function must be written
+ in inline assembler.
+ This is particularly useful for interrupt functions, which can have a large
+ (and often unnecessary) prologue/epilogue.
+ For example, compare the code generated by these two functions:
+\layout Verse
+
+
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+ data unsigned char counter;
\newline
\newline
+void simpleInterrupt(void) interrupt
+\begin_inset LatexCommand \index{interrupt}
-\family typewriter
-replace {
+\end_inset
+
+ 1
\newline
-\SpecialChar ~
-\SpecialChar ~
-mov %1,a
+{
\newline
\SpecialChar ~
\SpecialChar ~
-mov a,%1
-\newline
-} by {
-\newline
\SpecialChar ~
\SpecialChar ~
-mov %1,a
+counter++;
\newline
}
-\family default
-
\newline
\newline
-The above rule will change the following assembly
-\begin_inset LatexCommand \index{Assembler routines}
-
-\end_inset
-
- sequence:
+void nakedInterrupt(void) interrupt 2 _naked
\newline
-
+{
\newline
-
-\family typewriter
\SpecialChar ~
\SpecialChar ~
-mov r1,a
-\newline
\SpecialChar ~
\SpecialChar ~
-mov a,r1
-\family default
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
-\newline
\newline
-to
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter ; does not change flags, no need to save psw
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+; MUST explicitly include ret or reti in _naked function.
\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
-\family typewriter
-mov r1,a
-\family default
+\end_inset
+;
\newline
+}
+\layout Standard
-\newline
-Note: All occurrences of a
-\emph on
-%n
-\emph default
- (pattern variable) must denote the same string.
- With the above rule, the assembly sequence:
-\newline
+For an 8051 target, the generated simpleInterrupt looks like:
+\layout Verse
-\newline
\family typewriter
+_simpleInterrupt:
+\newline
\SpecialChar ~
\SpecialChar ~
-mov r1,a
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+acc
\newline
\SpecialChar ~
\SpecialChar ~
-mov a,r2
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
\newline
-will remain unmodified.
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
\newline
-
-\newline
-Other special case optimizations may be added by the user (via
-\emph on
--
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
-
-\backslash
-/
-\end_inset
-
--peep-file option
-\emph default
-).
- E.g.
- some variants of the 8051 MCU allow only
-\family typewriter
-ajmp
-\family default
- and
-\family typewriter
-acall
-\family default
-.
- The following two rules will change all
-\family typewriter
-ljmp
-\family default
- and
-\family typewriter
-lcall
-\family default
- to
-\family typewriter
-ajmp
-\family default
- and
-\family typewriter
-acall
-\family default
-
-\newline
-
-\newline
-
-\family typewriter
-replace { lcall %1 } by { acall %1 }
-\newline
-replace { ljmp %1 } by { ajmp %1 }
-\family default
-
-\newline
-
-\newline
-The
-\emph on
-inline-assembler code
-\emph default
- is also passed through the peep hole optimizer, thus the peephole optimizer
- can also be used as an assembly level macro expander.
- The rules themselves are MCU dependent whereas the rule language infra-structur
-e is MCU independent.
- Peephole optimization rules for other MCU can be easily programmed using
- the rule language.
-\newline
-
-\newline
-The syntax for a rule is as follows:
-\newline
-
-\newline
-
-\family typewriter
-rule := replace [ restart ] '{' <assembly sequence> '
-\backslash
-n'
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw
\newline
\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- '}' by '{' '
-\backslash
-n'
-\newline
\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- <assembly sequence> '
-\backslash
-n'
-\newline
\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- '}' [if <functionName> ] '
-\backslash
-n'
-\newline
-
-\family default
-
-\newline
-<assembly sequence> := assembly instruction (each instruction including
- labels must be on a separate line).
-\newline
-
-\newline
-The optimizer will apply to the rules one by one from the top in the sequence
- of their appearance, it will terminate when all rules are exhausted.
- If the 'restart' option is specified, then the optimizer will start matching
- the rules again from the top, this option for a rule is expensive (performance)
-, it is intended to be used in situations where a transformation will trigger
- the same rule again.
- An example of this (not a good one, it has side effects) is the following
- rule:
-\newline
-
-\newline
-
-\family typewriter
-replace restart {
-\newline
\SpecialChar ~
+mov\SpecialChar ~
\SpecialChar ~
-pop %1
-\newline
\SpecialChar ~
\SpecialChar ~
-push %1 } by {
+\SpecialChar ~
+psw,#0x00
\newline
\SpecialChar ~
\SpecialChar ~
-; nop
-\newline
-}
-\family default
-
-\newline
-
-\newline
-Note that the replace pattern cannot be a blank, but can be a comment line.
- Without the 'restart' option only the inner most 'pop' 'push' pair would
- be eliminated, i.e.:
-\newline
-
-\newline
-
-\family typewriter
\SpecialChar ~
\SpecialChar ~
-pop ar1
-\newline
+inc\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-pop ar2
-\newline
\SpecialChar ~
\SpecialChar ~
-push ar2
+_counter
\newline
\SpecialChar ~
\SpecialChar ~
-push ar1
-\family default
-
-\newline
-
-\newline
-would result in:
-\newline
-
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw
\newline
-
-\family typewriter
\SpecialChar ~
\SpecialChar ~
-pop ar1
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
\newline
\SpecialChar ~
\SpecialChar ~
-; nop
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
\newline
\SpecialChar ~
\SpecialChar ~
-push ar1
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+acc
\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+reti
+\layout Standard
-\emph on
-with
-\emph default
- the restart option the rule will be applied again to the resulting code
- and then all the pop-push pairs will be eliminated to yield:
-\newline
+whereas nakedInterrupt looks like:
+\layout Verse
-\newline
\family typewriter
+_nakedInterrupt:
+\newline
\SpecialChar ~
\SpecialChar ~
-; nop
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter ; does not change flags, no need to save psw
\newline
\SpecialChar ~
\SpecialChar ~
-; nop
-\family default
+\SpecialChar ~
+\SpecialChar ~
+reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+; MUST explicitly include ret or reti in _naked function
+\layout Standard
-\newline
+The related directive #pragma exclude
+\begin_inset LatexCommand \index{\#pragma exclude}
-\newline
-A conditional function can be attached to a rule.
- Attaching rules are somewhat more involved, let me illustrate this with
- an example.
-\newline
+\end_inset
-\newline
+ allows a more fine grained control over pushing & popping
+\begin_inset LatexCommand \index{push/pop}
+
+\end_inset
+
+ the registers.
+\layout Standard
+While there is nothing preventing you from writing C code inside a
\family typewriter
-replace {
-\newline
-\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-ljmp %5
-\newline
-%2:
-\newline
-} by {
-\newline
-\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-sjmp %5
-\newline
-%2:
-\newline
-} if labelInRange
+_naked
\family default
+ function, there are many ways to shoot yourself in the foot doing this,
+ and it is recommended that you stick to inline assembler.
+\layout Subsection
-\newline
+Use of Labels within Inline Assembler
+\layout Standard
-\newline
-The optimizer does a look-up of a function name table defined in function
-
-\emph on
-callFuncByName
-\emph default
- in the source file SDCCpeeph.c, with the name
+SDCC allows the use of in-line assembler with a few restrictions regarding
+ labels.
+ In older versions of the compiler all labels defined within inline assembler
+ code
\emph on
-labelInRange
+had to be
\emph default
-.
- If it finds a corresponding entry the function is called.
- Note there can be no parameters specified for these functions, in this
- case the use of
+ of the form
\emph on
-%5
+nnnnn$
\emph default
- is crucial, since the function
+ where nnnn is a number less than 100 (which implies a limit of utmost 100
+ inline assembler labels
\emph on
-labelInRange
+per function
\emph default
- expects to find the label in that particular variable (the hash table containin
-g the variable bindings is passed as a parameter).
- If you want to code more such functions, take a close look at the function
- labelInRange and the calling mechanism in source file SDCCpeeph.c.
- I know this whole thing is a little kludgey, but maybe some day we will
- have some better means.
- If you are looking at this file, you will also see the default rules that
- are compiled into the compiler, you can add your own rules in the default
- set there if you get tired of specifying the -
-\begin_inset ERT
-status Collapsed
+\noun on
+)
+\noun default
+.
+
+\layout Verse
-\layout Standard
-\backslash
-/
-\end_inset
+\family typewriter
+_asm
+\begin_inset LatexCommand \index{\_asm}
--peep-file option.
-\layout Subsection
+\end_inset
-Pragmas
-\begin_inset LatexCommand \index{Pragmas}
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b,#10
+\newline
+00001$:
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+djnz\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b,00001$
+\newline
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
\end_inset
-
+ ;
\layout Standard
-SDCC supports the following #pragma directives.
-\layout Itemize
-
-SAVE
-\begin_inset LatexCommand \index{\#pragma SAVE}
+Inline assembler code cannot reference any C-Labels, however it can reference
+ labels
+\begin_inset LatexCommand \index{Labels}
\end_inset
- - this will save all current options to the SAVE/RESTORE stack.
- See RESTORE.
-\layout Itemize
+ defined by the inline assembler, e.g.:
+\layout Verse
-RESTORE
-\begin_inset LatexCommand \index{\#pragma RESTORE}
-\end_inset
+\family typewriter
+foo() {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some c code */
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_asm
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+; some assembler code
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ljmp $0003
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some more c code */
+\newline
+clabel:\SpecialChar ~
+\SpecialChar ~
+/* inline assembler cannot reference this label */
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_asm
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+$0003: ;label (can be referenced by inline assembler only)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm ;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some more c code */
+\newline
+}
+\layout Standard
- - will restore saved options from the last save.
- SAVEs & RESTOREs can be nested.
- SDCC uses a SAVE/RESTORE stack: SAVE pushes current options to the stack,
- RESTORE pulls current options from the stack.
- See SAVE.
-\layout Itemize
+In other words inline assembly code can access labels defined in inline
+ assembly within the scope of the function.
+ The same goes the other way, i.e.
+ labels defines in inline assembly can not be accessed by C statements.
+\layout Section
-NOGCSE
-\begin_inset LatexCommand \index{\#pragma NOGCSE}
+Interfacing with Assembler Code
+\begin_inset LatexCommand \index{Assembler routines}
\end_inset
- - will stop global subexpression elimination.
-\layout Itemize
-
-NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
-
-\end_inset
- - will stop loop induction optimizations.
-\layout Itemize
+\layout Subsection
-NOJTBOUND
-\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+Global Registers used for Parameter Passing
+\begin_inset LatexCommand \index{Parameter passing}
\end_inset
- - will not generate code for boundary value checking, when switch statements
- are turned into jump-tables.
-\layout Itemize
-NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+\layout Standard
+
+The compiler always uses the global registers
+\emph on
+DPL, DPH
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
\end_inset
- - the compiler will not overlay the parameters and local variables of a
- function.
-\layout Itemize
-LESS_PEDANTIC
-\begin_inset LatexCommand \index{\#pragma LESS\_PEDANTIC}
+\begin_inset LatexCommand \index{DPTR}
\end_inset
- - the compiler will not warn you anymore for obvious mistakes, you'r on
- your own now ;-(
-\layout Itemize
-
-NOLOOPREVERSE
-\begin_inset LatexCommand \index{\#pragma NOLOOPREVERSE}
+, B
+\begin_inset LatexCommand \index{B (mcs51, ds390 register)}
\end_inset
- - Will not do loop reversal optimization
-\layout Itemize
-
-EXCLUDE
-\begin_inset LatexCommand \index{\#pragma EXCLUDE}
+
+\emph default
+and
+\emph on
+ ACC
+\begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}
\end_inset
- NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation of
- pair of push/pop
-\begin_inset LatexCommand \index{push/pop}
-\end_inset
-
- instruction in ISR function (using interrupt
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
+\emph default
+ to pass the first parameter to a routine.
+ The second parameter onwards is either allocated on the stack (for reentrant
+ routines or if -
+\begin_inset ERT
+status Collapsed
- keyword).
- The directive should be placed immediately before the ISR function definition
- and it affects ALL ISR functions following it.
- To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
-EXCLUDE\SpecialChar ~
-none
-\begin_inset LatexCommand \index{\#pragma EXCLUDE}
+\layout Standard
+\backslash
+/
\end_inset
-.
-\layout Itemize
-
-NOIV
-\begin_inset LatexCommand \index{\#pragma NOIV}
-
-\end_inset
+-stack-auto is used) or in data / xdata memory (depending on the memory
+ model).
+
+\layout Subsection
- - Do not generate interrupt vector table entries for all ISR functions
- defined after the pragma.
- This is useful in cases where the interrupt vector table must be defined
- manually, or when there is a secondary, manually defined interrupt vector
- table (e.g.
- for the autovector feature of the Cypress EZ-USB FX2).
-\layout Itemize
+Assembler Routine (non-reentrant)
+\layout Standard
-CALLEE-SAVES
-\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+In the following example
+\begin_inset LatexCommand \index{reentrant}
\end_inset
-\begin_inset LatexCommand \index{function prologue}
+\begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
\end_inset
- function1[,function2[,function3...]] - The compiler by default uses a caller
- saves convention for register saving across function calls, however this
- can cause unneccessary register pushing & popping when calling small functions
- from larger functions.
- This option can be used to switch off the register saving convention for
- the function names specified.
- The compiler will not save registers when calling these functions, extra
- code need to be manually inserted at the entry & exit for these functions
- to save & restore the registers used by these functions, this can SUBSTANTIALLY
- reduce code & improve run time performance of the generated code.
- In the future the compiler (with interprocedural analysis) may be able
- to determine the appropriate scheme to use for each function call.
- If -
-\begin_inset ERT
-status Collapsed
-
-\layout Standard
+ the function c_func calls an assembler routine asm_func, which takes two
+ parameters
+\begin_inset LatexCommand \index{function parameter}
-\backslash
-/
\end_inset
--callee-saves command line option is used, the function names specified
- in #pragma\SpecialChar ~
-CALLEE-SAVES
-\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+.
+\layout Verse
-\end_inset
- is appended to the list of functions specified in the command line.
-\layout Standard
+\family typewriter
+extern int asm_func(unsigned char, unsigned char);
+\newline
-The pragma's are intended to be used to turn-off certain optimizations which
- might cause the compiler to generate extra stack / data space to store
- compiler generated temporary variables.
- This usually happens in large functions.
- Pragma directives should be used as shown in the following example, they
- are used to control options & optimizations for a given function; pragmas
- should be placed before and/or after a function, placing pragma's inside
- a function body could have unpredictable results.
+\newline
+int c_func (unsigned char i, unsigned char j)
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return asm_func(i,j);
+\newline
+}
\newline
\newline
+int main()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return c_func(10,9);
+\newline
+}
+\layout Standard
-\family typewriter
-#pragma SAVE
-\begin_inset LatexCommand \index{\#pragma SAVE}
+The corresponding assembler function is:
+\layout Verse
-\end_inset
- /* save the current settings */
+\family typewriter
+.globl _asm_func_PARM_2
\newline
-#pragma NOGCSE
-\begin_inset LatexCommand \index{\#pragma NOGCSE}
-
-\end_inset
-
- /* turnoff global subexpression elimination */
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.globl _asm_func
\newline
-#pragma NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
-
-\end_inset
-
- /* turn off induction optimizations */
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area OSEG
\newline
-int foo ()
+_asm_func_PARM_2:
\newline
-{
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.ds 1
\newline
\SpecialChar ~
- \SpecialChar ~
- ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area CSEG
+\newline
+_asm_func:
\newline
\SpecialChar ~
- \SpecialChar ~
- /* large code */
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+a,dpl
\newline
\SpecialChar ~
- \SpecialChar ~
- ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+a,_asm_func_PARM_2
\newline
-}
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl,a
\newline
-#pragma RESTORE
-\begin_inset LatexCommand \index{\#pragma RESTORE}
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
\end_inset
- /* turn the optimizations back on */
-\family default
-
-\newline
-
+,#0x00
\newline
-The compiler will generate a warning message when extra space is allocated.
- It is strongly recommended that the SAVE and RESTORE pragma's be used when
- changing options for a function.
-\layout Subsection
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ret
+\layout Standard
-Library Routines
-\emph on
- <pending: this is messy and incomplete>
-\emph default
-
-\layout Enumerate
+Note here that the return values
+\begin_inset LatexCommand \index{return value}
-Compiler support routines (_gptrget, _mulint etc)
-\layout Enumerate
+\end_inset
-Stdclib functions (puts, printf, strcat etc)
-\layout Enumerate
+ are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
+ two byte values.
+ 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
+b' & 'acc' for four byte values.
+\layout Standard
-Math functions (sin, pow, sqrt etc)
-\layout Comment
+The parameter naming convention is _<function_name>_PARM_<n>, where n is
+ the parameter number starting from 1, and counting from the left.
+ The first parameter is passed in
+\begin_inset Quotes eld
+\end_inset
-license statements for the libraries are missing
-\layout Subsection
+dpl
+\begin_inset Quotes erd
+\end_inset
-Interfacing with Assembly Routines
-\begin_inset LatexCommand \index{Assembler routines}
+ for a one byte parameter,
+\begin_inset Quotes eld
+\end_inset
+dptr
+\begin_inset Quotes erd
\end_inset
+ for two bytes,
+\begin_inset Quotes eld
+\end_inset
-\layout Subsubsection
+b,dptr
+\begin_inset Quotes erd
+\end_inset
-Global Registers used for Parameter Passing
-\begin_inset LatexCommand \index{Parameter passing}
+ for three bytes and
+\begin_inset Quotes eld
+\end_inset
+acc,b,dptr
+\begin_inset Quotes erd
\end_inset
+ for a four bytes parameter.
+ The variable name for the second parameter will be _<function_name>_PARM_2.
+\newline
+\newline
+Assemble the assembler routine with the following command:
+\newline
+
+\newline
+
+\family sans
+\series bold
+asx8051 -losg asmfunc.asm
+\newline
+
+\newline
+
+\family default
+\series default
+Then compile and link the assembler routine to the C source file with the
+ following command:
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcc cfunc.c asmfunc.rel
+\layout Subsection
+
+Assembler Routine (reentrant)
\layout Standard
-The compiler always uses the global registers
-\emph on
-DPL, DPH
-\begin_inset LatexCommand \index{DPTR, DPH, DPL}
+In this case
+\begin_inset LatexCommand \index{reentrant}
\end_inset
-, B
-\begin_inset LatexCommand \index{B (register)}
+
+\begin_inset LatexCommand \index{Assembler routines (reentrant)}
\end_inset
-
-\emph default
-and
-\emph on
- ACC
-\begin_inset LatexCommand \index{ACC}
+ the second parameter
+\begin_inset LatexCommand \index{function parameter}
\end_inset
+ onwards will be passed on the stack, the parameters are pushed from right
+ to left i.e.
+ after the call the leftmost parameter will be on the top of the stack.
+ Here is an example:
+\layout Verse
+
-\emph default
- to pass the first parameter to a routine.
- The second parameter onwards is either allocated on the stack (for reentrant
- routines or if -
-\begin_inset ERT
-status Collapsed
+\family typewriter
+extern int asm_func(unsigned char, unsigned char);
+\newline
+
+\newline
+int c_func (unsigned char i, unsigned char j) reentrant
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return asm_func(i,j);
+\newline
+}
+\newline
+\newline
+int main()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return c_func(10,9);
+\newline
+}
\layout Standard
-\backslash
-/
+The corresponding assembler routine is:
+\layout Verse
+
+
+\family typewriter
+.globl _asm_func
+\newline
+_asm_func:
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push _bp
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov _bp,sp
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r2,dpl
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,_bp
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,#0xfd
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r0,a
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,#0xfc ;?
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r1,a
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,@r0
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,r2 ;?
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dpl,a
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dph,#0x00
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov sp,_bp
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop _bp
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ret
+\layout Standard
+
+The compiling and linking procedure remains the same, however note the extra
+ entry & exit linkage required for the assembler code, _bp is the stack
+ frame pointer and is used to compute the offset into the stack for parameters
+ and local variables.
+\layout Section
+
+int (16 bit)
+\begin_inset LatexCommand \index{int (16 bit)}
+
\end_inset
--stack-auto is used) or in the internal / external ram (depending on the
- memory model).
-
-\layout Subsubsection
+ and long (32 bit)
+\begin_inset LatexCommand \index{long (32 bit)}
-Assembler Routine(non-reentrant
-\begin_inset LatexCommand \index{reentrant}
+\end_inset
+
+ Support
+\layout Standard
+
+For signed & unsigned int (16 bit) and long (32 bit) variables, division,
+ multiplication and modulus operations are implemented by support routines.
+ These support routines are all developed in ANSI-C to facilitate porting
+ to other MCUs, although some model specific assembler optimizations are
+ used.
+ The following files contain the described routines, all of them can be
+ found in <installdir>/share/sdcc/lib.
+\newline
+
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="11" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+\layout Standard
+
+
+\series bold
+Function
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-)
-\begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
+\layout Standard
+
+\series bold
+Description
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+_mulint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-In the following example the function cfunc calls an assembler routine asm_func,
- which takes two parameters.
-\newline
+16 bit multiplication
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\family typewriter
-extern int asm_func(unsigned char, unsigned char);
-\newline
+_divsint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-int c_func (unsigned char i, unsigned char j)
-\newline
-{
-\newline
+\layout Standard
+
+ signed 16 bit division (calls _divuint)
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_divuint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+ unsigned 16 bit division
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_modsint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+signed 16 bit modulus (calls _moduint)
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_moduint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+unsigned 16 bit modulus
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_mullong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+32 bit multiplication
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_divslong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+ signed 32 division (calls _divulong)
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_divulong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+unsigned 32 division
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_modslong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+ signed 32 bit modulus (calls _modulong)
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+_modulong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+unsigned 32 bit modulus
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\layout Standard
+
+Since they are compiled as
+\emph on
+non-reentrant
+\emph default
+
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+, interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ service routines should not do any of the above operations.
+ If this is unavoidable then the above routines will need to be compiled
+ with the
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
+\emph default
+ option, after which the source program will have to be compiled with
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-int-long-reent
+\begin_inset LatexCommand \index{-\/-int-long-reent}
+
+\end_inset
+
+
+\emph default
+ option.
+ Notice that you don't have to call these routines directly.
+ The compiler will use them automatically every time an integer operation
+ is required.
+\layout Section
+
+Floating Point Support
+\begin_inset LatexCommand \index{Floating point support}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC supports IEEE (single precision 4 bytes) floating point numbers.The
+ floating point support routines are derived from gcc's floatlib.c and consist
+ of the following routines:
+\newline
+
+\layout Standard
+\align center
+
+\size footnotesize
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="17" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+Function
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Description
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
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+_fsadd.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+add floating point numbers
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+\end_inset
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+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+
+\layout Standard
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+
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+
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+\family default
+\series default
+\shape default
+\size default
+\emph default
+\bar default
+\noun default
+\color default
+c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
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+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+
+\layout Standard
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+
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+\end_inset
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+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
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+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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+
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+<row topline="true">
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+
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+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
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+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
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+\color none
+_ulong2fs.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
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+\bar no
+\noun off
+\color none
+convert unsigned long to floating point number
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_long2fs.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+convert long to floating point number
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\layout Standard
+
+These support routines are developed in ANSI-C so there is room for space
+ and speed improvement.
+ Note if all these routines are used simultaneously the data space might
+ overflow.
+ For serious floating point usage it is recommended that the large model
+ be used.
+ Also notice that you don't have to call this routines directly.
+ The compiler will use them automatically every time a floating point operation
+ is required.
+\layout Section
+
+Library Routines
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+
+\layout Standard
+
+
+\emph on
+<pending: this is messy and incomplete - a little more information is in
+ sdcc/doc/libdoc.txt
+\emph default
+ >
+\layout Subsection
+
+Compiler support routines (_gptrget, _mulint etc.)
+\layout Subsection
+
+Stdclib functions (puts, printf, strcat etc.)
+\layout Subsubsection
+
+<stdio.h>
+\layout Standard
+
+
+\begin_inset LatexCommand \index{<stdio.h>}
+
+\end_inset
+
+As usual on embedded systems you have to provide your own
+\family typewriter
+getchar()
+\begin_inset LatexCommand \index{getchar()}
+
+\end_inset
+
+
+\family default
+and
+\family typewriter
+putchar()
+\begin_inset LatexCommand \index{putchar()}
+
+\end_inset
+
+
+\family default
+ routines.
+ SDCC does not know whether the system connects to a serial line with or
+ without handshake, LCD, keyboard or other device.
+ You'll find examples for serial routines f.e.
+ in sdcc/device/lib.
+\layout Standard
+
+If you're short on memory you might want to use
+\family typewriter
+printf_small()
+\family default
+
+\emph on
+instead
+\emph default
+ of
+\family typewriter
+ printf()
+\begin_inset LatexCommand \index{printf()}
+
+\end_inset
+
+.
+
+\family default
+ For the mcs51 there is an assembly version
+\family typewriter
+printf_fast()
+\family default
+ which should fit the requirements of many embedded systems (by unsetting
+ #defines it can be customized to
+\emph on
+not
+\emph default
+ support long variables and field widths).
+\layout Subsection
+
+Math functions (sin, pow, sqrt etc.)
+\layout Subsection
+
+Other libraries
+\layout Standard
+
+Libraries
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+ included in SDCC should have a license at least as liberal as the GNU Lesser
+ General Public License
+\begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
+
+\end_inset
+
+
+\emph on
+LGPL
+\emph default
+.
+\layout Comment
+
+license statements for the libraries are missing.
+ sdcc/device/lib/ser_ir.c
+\layout Comment
+
+or _decdptr f.e.
+ come with a GPL (as opposed to LGPL) License - this will not be liberal
+ enough for many embedded programmers.
+\layout Standard
+
+If you have ported some library or want to share experience about some code
+ which f.e.
+ falls into any of these categories Busses (I
+\begin_inset Formula $^{\textrm{2}}$
+\end_inset
+
+C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
+ cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
+ Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list
+\begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}
+
+\end_inset
+
+\SpecialChar ~
+would certainly like to hear about it.
+ Programmers coding for embedded systems are not especially famous for being
+ enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
+e these references are very valuable.
+ Let's help to create a climate where information is shared.
+\layout Section
+
+Memory Models
+\layout Subsection
+
+MCS51 Memory Models
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{MCS51 memory model}
+
+\end_inset
+
+
+\layout Subsubsection
+
+Small and Large
+\layout Standard
+
+SDCC allows two memory models for MCS51 code,
+\shape slanted
+small
+\shape default
+ and
+\shape slanted
+large
+\shape default
+.
+ Modules compiled with different memory models should
+\emph on
+never
+\emph default
+ be combined together or the results would be unpredictable.
+ The library routines supplied with the compiler are compiled as both small
+ and large.
+ The compiled library modules are contained in separate directories as small
+ and large so that you can link to either set.
+
+\layout Standard
+
+When the large model is used all variables declared without a storage class
+ will be allocated into the external ram, this includes all parameters and
+ local variables (for non-reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+ functions).
+ When the small model is used variables without storage class are allocated
+ in the internal ram.
+\layout Standard
+
+Judicious usage of the processor specific storage classes
+\begin_inset LatexCommand \index{Storage class}
+
+\end_inset
+
+ and the 'reentrant' function type will yield much more efficient code,
+ than using the large model.
+ Several optimizations are disabled when the program is compiled using the
+ large model, it is therefore recommended that the small model be used unless
+ absolutely required.
+\layout Subsubsection
+
+External Stack
+\begin_inset LatexCommand \label{sub:External-Stack}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{External stack (mcs51)}
+
+\end_inset
+
+
+\layout Standard
+
+
+\series bold
+Attention
+\series default
+: this option wasn't maintained for a long time and is quite buggy.
+ Small programs might work.
+ You've been warned!
+\layout Standard
+
+The external stack (-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack option
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+) is located in pdata
+\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
+
+\end_inset
+
+ memory (usually at the start of the external ram segment) and is 256 bytes
+ in size.
+ When -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack option is used to compile the program, the parameters and local
+ variables
+\begin_inset LatexCommand \index{local variables}
+
+\end_inset
+
+ of all reentrant functions are allocated in this area.
+ This option is provided for programs with large stack space requirements.
+ When used with the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+ option, all parameters and local variables are allocated on the external
+ stack (note: support libraries will need to be recompiled with the same
+ options).
+\layout Standard
+
+The compiler outputs the higher order address byte of the external ram segment
+ into port P2
+\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
+
+\end_inset
+
+ (see also section
+\begin_inset LatexCommand \ref{sub:MCS51-variants}
+
+\end_inset
+
+), therefore when using the External Stack option, this port
+\emph on
+may not
+\emph default
+ be used by the application program.
+\layout Subsection
+
+DS390 Memory Model
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{DS390 memory model}
+
+\end_inset
+
+
+\layout Standard
+
+The only model supported is Flat 24
+\begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}
+
+\end_inset
+
+.
+ This generates code for the 24 bit contiguous addressing mode of the Dallas
+ DS80C390 part.
+ In this mode, up to four meg of external RAM or code space can be directly
+ addressed.
+ See the data sheets at www.dalsemi.com for further information on this part.
+\newline
+
+\newline
+Note that the compiler does not generate any code to place the processor
+ into 24 bitmode (although
+\emph on
+tinibios
+\emph default
+ in the ds390 libraries will do that for you).
+ If you don't use
+\emph on
+tinibios
+\emph default
+
+\begin_inset LatexCommand \index{Tinibios (DS390)}
+
+\end_inset
+
+, the boot loader or similar code must ensure that the processor is in 24
+ bit contiguous addressing mode before calling the SDCC startup code.
+\newline
+
+\newline
+Like the
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-large
+\emph default
+ option, variables will by default be placed into the XDATA segment.
+
+\newline
+
+\newline
+Segments may be placed anywhere in the 4 meg address space using the usual
+ -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-*-loc options.
+ Note that if any segments are located above 64K, the -r flag must be passed
+ to the linker to generate the proper segment relocations, and the Intel
+ HEX output format must be used.
+ The -r flag can be passed to the linker by using the option
+\emph on
+-Wl-r
+\emph default
+ on the SDCC command line.
+ However, currently the linker can not handle code segments > 64k.
+\layout Section
+
+Pragmas
+\begin_inset LatexCommand \index{Pragmas}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC supports the following #pragma directives:
+\layout Itemize
+
+save
+\begin_inset LatexCommand \index{\#pragma save}
+
+\end_inset
+
+ - this will save all current options to the save/restore stack.
+ See restore.
+\layout Itemize
+
+restore
+\begin_inset LatexCommand \index{\#pragma restore}
+
+\end_inset
+
+ - will restore saved options from the last save.
+ saves & restores can be nested.
+ SDCC uses a save/restore stack: save pushes current options to the stack,
+ restore pulls current options from the stack.
+ See save.
+\layout Itemize
+
+nogcse
+\begin_inset LatexCommand \index{\#pragma nogcse}
+
+\end_inset
+
+ - will stop global common subexpression elimination.
+\layout Itemize
+
+noinduction
+\begin_inset LatexCommand \index{\#pragma noinduction}
+
+\end_inset
+
+ - will stop loop induction optimizations.
+\layout Itemize
+
+nojtbound
+\begin_inset LatexCommand \index{\#pragma nojtbound}
+
+\end_inset
+
+ - will not generate code for boundary value checking, when switch statements
+ are turned into jump-tables (dangerous).
+ For more details see section
+\begin_inset LatexCommand \ref{sub:'switch'-Statements}
+
+\end_inset
+
+.
+\layout Itemize
+
+nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
+
+\end_inset
+
+ - the compiler will not overlay the parameters and local variables of a
+ function.
+\layout Itemize
+
+less_pedantic
+\begin_inset LatexCommand \index{\#pragma less\_pedantic}
+
+\end_inset
+
+ - the compiler will not warn you anymore for obvious mistakes, you'r on
+ your own now ;-(
+\layout Itemize
+
+noloopreverse
+\begin_inset LatexCommand \index{\#pragma noloopreverse}
+
+\end_inset
+
+ - Will not do loop reversal optimization
+\layout Itemize
+
+exclude
+\begin_inset LatexCommand \index{\#pragma exclude}
+
+\end_inset
+
+ none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation of
+ pair of push/pop
+\begin_inset LatexCommand \index{push/pop}
+
+\end_inset
+
+ instruction in ISR function (using interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ keyword).
+ The directive should be placed immediately before the ISR function definition
+ and it affects ALL ISR functions following it.
+ To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
+exclude\SpecialChar ~
+none
+\begin_inset LatexCommand \index{\#pragma exclude}
+
+\end_inset
+
+.
+\layout Itemize
+
+noiv
+\begin_inset LatexCommand \index{\#pragma noiv}
+
+\end_inset
+
+ - Do not generate interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ vector table entries for all ISR functions defined after the pragma.
+ This is useful in cases where the interrupt vector table must be defined
+ manually, or when there is a secondary, manually defined interrupt vector
+ table (e.g.
+ for the autovector feature of the Cypress EZ-USB FX2).
+ More elegantly this can be achieved by obmitting the optional interrupt
+ number after the interrupt keyword, see section
+\begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}
+
+\end_inset
+
+\SpecialChar ~
+about interrupts.
+\layout Itemize
+
+callee_saves
+\begin_inset LatexCommand \index{\#pragma callee\_saves}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{function prologue}
+
+\end_inset
+
+ function1[,function2[,function3...]] - The compiler by default uses a caller
+ saves convention for register saving across function calls, however this
+ can cause unnecessary register pushing & popping
+\begin_inset LatexCommand \index{push/pop}
+
+\end_inset
+
+ when calling small functions from larger functions.
+ This option can be used to switch off the register saving convention for
+ the function names specified.
+ The compiler will not save registers when calling these functions, extra
+ code need to be manually inserted at the entry & exit for these functions
+ to save & restore the registers used by these functions, this can SUBSTANTIALLY
+ reduce code & improve run time performance of the generated code.
+ In the future the compiler (with inter procedural analysis) may be able
+ to determine the appropriate scheme to use for each function call.
+ If -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-callee-saves command line option is used, the function names specified
+ in #pragma\SpecialChar ~
+callee_saves
+\begin_inset LatexCommand \index{\#pragma callee\_saves}
+
+\end_inset
+
+ is appended to the list of functions specified in the command line.
+\layout Standard
+
+SDCPP supports the following #pragma directives:
+\layout Itemize
+
+preproc_asm
+\begin_inset LatexCommand \index{\#pragma preproc\_asm}
+
+\end_inset
+
+ (+ | -) - switch _asm _endasm block preprocessing on / off.
+ Default is on.
+\layout Standard
+
+The pragma's are intended to be used to turn-on or off certain optimizations
+ which might cause the compiler to generate extra stack / data space to
+ store compiler generated temporary variables.
+ This usually happens in large functions.
+ Pragma directives should be used as shown in the following example, they
+ are used to control options & optimizations for a given function; pragmas
+ should be placed before and/or after a function, placing pragma's inside
+ a function body could have unpredictable results.
+\layout Verse
+
+
+\family typewriter
+#pragma save
+\begin_inset LatexCommand \index{\#pragma save}
+
+\end_inset
+
+ \SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* save the current settings */
+\newline
+#pragma nogcse
+\begin_inset LatexCommand \index{\#pragma nogcse}
+
+\end_inset
+
+ \SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* turnoff global subexpression elimination */
+\newline
+#pragma noinduction
+\begin_inset LatexCommand \index{\#pragma noinduction}
+
+\end_inset
+
+ /* turn off induction optimizations */
+\newline
+int foo ()
+\newline
+{
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ ...
+
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ /* large code */
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ ...
+
+\newline
+}
+\newline
+#pragma restore
+\begin_inset LatexCommand \index{\#pragma restore}
+
+\end_inset
+
+ /* turn the optimizations back on */
+\layout Standard
+
+The compiler will generate a warning message when extra space is allocated.
+ It is strongly recommended that the save and restore pragma's be used when
+ changing options for a function.
+\layout Section
+
+Defines Created by the Compiler
+\layout Standard
+
+The compiler creates the following #defines
+\begin_inset LatexCommand \index{\#defines}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Defines created by the compiler}
+
+\end_inset
+
+:
+\newline
+
+\layout Standard
+
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="10" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\series bold
+#define
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\series bold
+Description
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC
+\begin_inset LatexCommand \index{SDCC}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+this Symbol is always defined
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_mcs51
+\begin_inset LatexCommand \index{SDCC\_mcs51}
+
+\end_inset
+
+ or SDCC_ds390
+\begin_inset LatexCommand \index{SDCC\_ds390}
+
+\end_inset
+
+ or SDCC_z80
+\begin_inset LatexCommand \index{SDCC\_z80}
+
+\end_inset
+
+, etc
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+depending on the model used (e.g.: -mds390
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+__mcs51
+\begin_inset LatexCommand \index{\_\_mcs51}
+
+\end_inset
+
+, __ds390
+\begin_inset LatexCommand \index{\_\_ds390}
+
+\end_inset
+
+, __hc08
+\begin_inset LatexCommand \index{\_\_hc08}
+
+\end_inset
+
+, __z80
+\begin_inset LatexCommand \index{\_\_z80}
+
+\end_inset
+
+, etc
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+depending on the model used (e.g.
+ -mz80)
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_STACK_AUTO
+\begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\emph default
+ option is used
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_MODEL_SMALL
+\begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-small
+\emph default
+ is used
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_MODEL_LARGE
+\begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-large
+\emph default
+ is used
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_USE_XSTACK
+\begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack
+\emph default
+ option is used
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_STACK_TENBIT
+\begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-mds390
+\emph default
+ is used
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+SDCC_MODEL_FLAT24
+\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+when
+\emph on
+-mds390
+\emph default
+ is used
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Chapter
+
+Notes on supported Processors
+\layout Section
+
+MCS51 variants
+\begin_inset LatexCommand \label{sub:MCS51-variants}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{MCS51 variants}
+
+\end_inset
+
+
+\layout Standard
+
+MCS51 processors are available from many vendors and come in many different
+ flavours.
+ While they might differ considerably in respect to Special Function Registers
+ the core MCS51 is usually not modified or is kept compatible.
+
+\layout Subsection
+
+pdata access by SFR
+\layout Standard
+
+With the upcome of devices with internal xdata and flash memory devices
+ using port P2
+\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
+
+\end_inset
+
+ as dedicated I/O port is becoming more popular.
+ Switching the high byte for pdata
+\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
+
+\end_inset
+
+ access which was formerly done by port P2 is then achieved by a Special
+ Function Register
+\begin_inset LatexCommand \index{sfr}
+
+\end_inset
+
+.
+ In well-established MCS51 tradition the address of this
+\emph on
+sfr
+\emph default
+ is where the chip designers decided to put it.
+ Needless to say that they didn't agree on a common name either.
+ As pdata addressing is used in the startup code for the initialization
+ of xdata variables a separate startup code should be used as described
+ in section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
+
+\end_inset
+
+.
+\layout Subsection
+
+Other Features available by SFR
+\layout Standard
+
+Some MCS51 variants offer features like Double DPTR
+\begin_inset LatexCommand \index{DPTR}
+
+\end_inset
+
+, multiple DPTR, decrementing DPTR, 16x16 Multiply.
+ These are currently not used for the MCS51 port.
+ If you absolutely need them you can fall back to inline assembly or submit
+ a patch to SDCC.
+\layout Section
+
+The Z80 and gbz80 port
+\layout Standard
+
+SDCC can target both the Zilog
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ and the Nintendo Gameboy's Z80-like gbz80
+\begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
+
+\end_inset
+
+.
+ The Z80 port is passed through the same
+\emph on
+regressions tests
+\begin_inset LatexCommand \index{Regression test}
+
+\end_inset
+
+
+\emph default
+ as the MCS51 and DS390 ports, so floating point support, support for long
+ variables and bitfield support is fine.
+ See mailing lists and forums about interrupt routines.
+\layout Standard
+
+As always, the code is the authoritative reference - see z80/ralloc.c and
+ z80/gen.c.
+ The stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ frame is similar to that generated by the IAR Z80 compiler.
+ IX is used as the base pointer, HL and IY are used as a temporary registers,
+ and BC and DE are available for holding variables.
+ Return values
+\begin_inset LatexCommand \index{return value}
+
+\end_inset
+
+ for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
+ bytes).
+ The gbz80 port use the same set of registers for the return values, but
+ in a different order of significance: E (one byte), DE (two bytes), or
+ HLDE (four bytes).
+\layout Section
+
+The HC08 port
+\layout Standard
+
+The port to the Motorola HC08
+\begin_inset LatexCommand \index{HC08}
+
+\end_inset
+
+ family has been added in October 2003, and is still undergoing some basic
+ development.
+ The code generator is complete, but the register allocation is still quite
+ unoptimized.
+ Some of the SDCC's standard C library functions have embedded non-HC08
+ inline assembly and so are not yet usable.
+\newline
+
+\newline
+
+\layout Section
+
+The PIC14 port
+\layout Standard
+
+The 14bit PIC
+\begin_inset LatexCommand \index{PIC14}
+
+\end_inset
+
+ port still requires a major effort from the development community.
+ However it can work for very simple code.
+\layout Subsection
+
+C code and 14bit PIC code page
+\begin_inset LatexCommand \index{code page (pic14)}
+
+\end_inset
+
+ and RAM banks
+\begin_inset LatexCommand \index{RAM bank (pic14)}
+
+\end_inset
+
+
+\layout Standard
+
+The linker organizes allocation for the code page and RAM banks.
+ It does not have intimate knowledge of the code flow.
+ It will put all the code section of a single asm file into a single code
+ page.
+ In order to make use of multiple code pages, separate asm files must be
+ used.
+ The compiler treats all functions of a single C file as being in the same
+ code page unless it is non static.
+ The compiler treats all local variables of a single C file as being in
+ the same RAM bank unless it is an extern.
+\newline
+
+\newline
+To get the best follow these guide lines:
+\layout Enumerate
+
+make local functions static, as non static functions require code page selection
+ overhead.
+\layout Enumerate
+
+Make local variables static as extern variables require RAM bank selection
+ overhead.
+\layout Enumerate
+
+For devices that have multiple code pages it is more efficient to use the
+ same number of files as pages, i.e.
+ for the 16F877 use 4 separate files and i.e.
+ for the 16F874 use 2 separate files.
+ This way the linker can put the code for each file into different code
+ pages and the compiler can allocate reusable variables more efficiently
+ and there's less page selection overhead.
+ And as for any 8 bit micro (especially for PIC 14 as they have a very simple
+ instruction set) use 'unsigned char' whereever possible instead of 'int'.
+\layout Subsection
+
+Creating a device include file
+\layout Standard
+
+For generating a device include file use the support perl script inc2h.pl
+ kept in directory support/script.
+\layout Subsection
+
+Interrupt code
+\layout Standard
+
+For the interrupt function, use the keyword 'interrupt'
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ with level number of 0 (PIC14 only has 1 interrupt so this number is only
+ there to avoid a syntax error - it ought to be fixed).
+ E.g.:
+\layout Verse
+
+
+\family typewriter
+void Intr(void) interrupt 0
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+T0IF = 0; /* Clear timer interrupt */
+\newline
+}
+\layout Standard
+
+Linking and assembling
+\newline
+For assembling you can use either GPUTILS'
+\begin_inset LatexCommand \index{gputils (pic tools)}
+
+\end_inset
+
+ gpasm.exe or MPLAB's mpasmwin.exe.
+ For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
+ If you use MPLAB and an interrupt function then the linker script file
+ vectors section will need to be enlarged to link with mplink.
+\newline
+
+\newline
+Here is a
+\family typewriter
+Makefile
+\family default
+ using GPUTILS:
+\layout Verse
+
+
+\family typewriter
+.c.o:
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+sdcc -S -V -mpic14 -p16F877 $<
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+gpasm -c $*.asm
+\newline
+
+\newline
+$(PRJ).hex: $(OBJS)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+gplink -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS)
+\layout Standard
+
+Here is a
+\family typewriter
+Makefile
+\family default
+ using MPLAB:
+\layout Verse
+
+
+\family typewriter
+.c.o:
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+sdcc -S -V -mpic14 -p16F877 $<
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mpasmwin /q /o $*.asm
+\newline
+
+\newline
+$(PRJ).hex: $(OBJS)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS)
+\layout Section
+
+The PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port
+\layout Standard
+
+The PIC16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+ port is the portion of SDCC that is responsible to produce code for the
+ Microchip
+\begin_inset LatexCommand \index{Microchip}
+
+\end_inset
+
+(TM) microcontrollers with 16 bit core.
+ Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
+\layout Subsection
+
+Global Options
+\layout Standard
+
+PIC16 port supports the standard command line arguments as supposed, with
+ the exception of certain cases that will be mentioned in the following
+ list:
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto Auto variables that are function parameters, will be saved on
+ stack by default.
+
+\emph on
+There is no need to specify this in the command line.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-float-reent All floating point functions are reentrant by default.
+
+\emph on
+There is no need to specifiy this in the command line.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-callee-saves See -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-all-callee-saves
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-all-callee-saves All function arguments are passed on stack by default.
+
+\emph on
+There is no need to specify this in the command line.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-fommit-frame-pointer Frame pointer will be omitted when the function uses
+ no local variables.
+\layout Subsection
+
+Port Specific Options
+\layout Standard
+
+The port specific options appear after the global options in the sdcc --help
+ output.
+\layout Subsubsection
+
+General Options
+\layout Standard
+
+General options enable certain port features and optimizations.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pgen-bank Instructs the port to insert BANKSEL directives before instructions
+ that use the Bank Select Register (BSR).
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pomit-config-words Instructs the port to omit the generation of the configurati
+on words.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pomit-ivt Instructs the port to omit the generation of the interrupt vectors
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pleave-reset-vector Used in conjuction with the previous command, instructs
+ the port NOT to omit the reset vector.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-model=[model] Used in conjuction with the command above.
+ Defines the stack model to be used, valid stack models are :
+\begin_deeper
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\emph on
+small
+\emph default
+ Selects small stack model.
+ 8 bit stack and frame pointers.
+ Supports 256 bytes stack size.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\emph on
+large
+\emph default
+ Selects large stack model.
+ 16 bit stack and frame pointers.
+ Supports 65536 bytes stack size.
+\end_deeper
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-preplace-udata-with=[kword] Replaces the default udata keyword for allocating
+ unitialized data variables with [kword].
+ Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
+\layout Subsubsection
+
+Debugging Options
+\layout Standard
+
+Debugging options enable extra debugging information in the output files.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug-xtra Similar to --debug, but dumps more information.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug-ralloc Force register allocator to dump <source>.d file with debugging
+ information.
+ <source> is the name of the file compiled.
+\layout List
+\labelwidthstring 00.00.0000
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-pcode-verbose Enable pcode debugging information in translation.
+\layout Subsection
+
+Preprocessor Macros
+\layout Standard
+
+PIC16 port defines the following preprocessor macros while translating a
+ source.
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="2" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Macro
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Description
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+pic18fxxxx
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+MCU Identification.
+
+\emph on
+xxxx
+\emph default
+ is the microcontrol identification number, i.e.
+ 452, 6620, etc
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Subsection
+
+Directories
+\layout Standard
+
+PIC16 port uses the following directories for searching header files and
+ libraries.
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="4">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Directory
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Description
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Target
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Command prefix
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PREFIX/sdcc/include/pic16
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PIC16 specific headers
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Compiler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+-I
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PREFIX/sdcc/lib/pic16
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PIC16 specific libraries
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+-L
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Subsection
+
+Pragmas
+\layout Standard
+
+PIC16 port currently supports the following pragmas:
+\layout List
+\labelwidthstring 00.00.0000
+
+stack pragma stack forces the code generator to initialize the stack & frame
+ pointers at a specific address.
+ This is an adhoc solution since gplink does not support yet stack.
+ When the gplink issue is resolved the pragma will be deprecated
+\begin_inset Foot
+collapsed true
+
+\layout Standard
+
+
+\emph on
+It is important to initialize the stack, otherwise strange things can happen.
+ Stack is not initialized by default because there are some sources that
+ do not require it.
+ (like library sources)
+\end_inset
+
+.
+\newline
+The stack pragma should be used only once in a project.
+ Multiple pragmas may result in indeterminate behaviour of the program.
+\newline
+If you omit setting the pragma the port emits a warning message before linking.
+ If not initializing the stack is desired ignore the message.
+\layout LyX-Code
+
+Example:
+\layout LyX-Code
+
+\layout LyX-Code
+
+/* initializes stack at RAM address 0x5ff*/
+\layout LyX-Code
+
+#pragma stack 0x5ff
+\layout LyX-Code
+
+\layout Subsection
+
+Header Files
+\layout Standard
+
+There is one main header file that can be included to the source files using
+ the pic16 port.
+ That file is the
+\series bold
+pic18fregs.h
+\series default
+.
+ This header file contains the definitions for the processor special registers,
+ so it is necessery if the soruce accesses them.
+ It can be included by adding the following line in the beginning of the
+ file:
+\layout LyX-Code
+
+#include <pic18fregs.h>
+\layout Standard
+
+The specific microcontroller is selected within the pic18fregs.h automatically,
+ so the same source can be used with a variety of devices.
+\layout Subsection
+
+Libraries
+\layout Standard
+
+The libraries that pic16 port depends on are the microcontroller device
+ libraries which contain the symbol definitions for the microcontroller
+ special function registers.
+ These libraries have the format pic18fxxxx.lib, where
+\emph on
+xxxx
+\emph default
+ is the microcontroller identification number.
+ The specific library is selected automatically by the compiler at link
+ stage according to the selected device.
+\layout Standard
+
+Libraries are created with gplib which is part of the gputils package
+\begin_inset LatexCommand \url{http://gputils.sourceforge.net}
+
+\end_inset
+
+.
+\layout Subsection
+
+Memory Models
+\layout Standard
+
+The following memory models are supported by PIC16 port:
+\layout Itemize
+
+small model
+\layout Itemize
+
+large model
+\layout Standard
+
+Memory model affects the default size of pointers within the source.
+ The sizes are shown in the next table:
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Pointer sizes according to memory model
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+small model
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+large model
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+code pointers
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16-bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+24-bits
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+data pointers
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16-bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16-bits
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Standard
+
+It is advisable that all sources within a project are compiled with the
+ same memory model.
+ If one wants to override the default memory model, this can be done by
+ declaring a pointer as
+\series bold
+far
+\series default
+ or
+\series bold
+near
+\series default
+.
+ Far selects large memory model's pointers, while near selects small memory
+ model's pointers.
+\layout Standard
+
+The standard device libraries (see 4.5.6) contain no reference to pointers,
+ so they can be used with both memory models.
+\layout Subsection
+
+Stack
+\layout Standard
+
+The stack implementation for the PIC16 port uses two indirect registers,
+ FSR1 and FSR2.
+\layout List
+\labelwidthstring 00.00.0000
+
+FSR1 is assigned as stack pointer
+\layout List
+\labelwidthstring 00.00.0000
+
+FSR2 is assigned as frame pointer
+\layout Standard
+
+The following stack models are supported by PIC16 port
+\layout Itemize
+
+small model
+\layout Itemize
+
+large model
+\layout Standard
+
+
+\noun on
+Small
+\noun default
+ model means that only the FSRxL byte is used to access stack and frame,
+ while
+\emph on
+\noun on
+large
+\emph default
+\noun default
+ uses both FSRxL and FSRxH registers.
+ The following table shows the stack/frame pointers sizes according to stack
+ model and the maximum space they can address:
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Stack & Frame pointer sizes according to stack model
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+small
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+large
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Stack pointer FSR1
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+8-bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16-bits
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Frame pointer FSR2
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+8-bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16-bits
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Standard
+
+
+\series bold
+Currently stack and frame pointers should be initialized explicit by the
+ user at the desired Data RAM position (see 4.5.5 Pragma Stack).
+ Uninitialized stack and frame pointers can result in unexpected behavior
+ of the resulting binary.
+\layout Subsection
+
+Function return values
+\layout Standard
+
+Return values from functions are placed to the appropriate registers following
+ a modified Microchip policy optimized for SDCC.
+ The following table shows these registers:
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="6" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+size
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+destination register
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+8 bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+WREG
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+16 bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PRODL:WREG
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+24 bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PRODH:PRODL:WREG
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+32 bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+FSR0L:PRODH:PRODL:WREG
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+>32 bits
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+on stack, FSR0 points to the beginning
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\layout Subsection
+
+Interrupts
+\layout Standard
+
+When entering an interrupt, currently the PIC16 port automatically saves
+ the following registers:
+\layout Itemize
+
+WREG
+\layout Itemize
+
+STATUS
+\layout Itemize
+
+BSR
+\layout Itemize
+
+PROD (PRODL and PRODH)
+\layout Itemize
+
+FSR0 (FSR0L and FSR0H)
+\layout Standard
+
+These registers are restored upon return from the interrupt routine
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+NOTE that when the _naked attribute is specified for an interrupt routine,
+ then NO registers are stored or restored.
+\end_inset
+
+.
+\layout Chapter
+
+Debugging with SDCDB
+\begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{sdcdb (debugger)}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC is distributed with a source level debugger
+\begin_inset LatexCommand \index{Debugger}
+
+\end_inset
+
+.
+ The debugger uses a command line interface, the command repertoire of the
+ debugger has been kept as close to gdb
+\begin_inset LatexCommand \index{gdb}
+
+\end_inset
+
+ (the GNU debugger) as possible.
+ The configuration and build process is part of the standard compiler installati
+on, which also builds and installs the debugger in the target directory
+ specified during configuration.
+ The debugger allows you debug BOTH at the C source and at the ASM source
+ level.
+ Sdcdb is available on Unix platforms only.
+\layout Section
+
+Compiling for Debugging
+\layout Standard
+
+The \SpecialChar \-
+\SpecialChar \-
+debug option must be specified for all files for which debug information
+ is to be generated.
+ The complier generates a .adb file for each of these files.
+ The linker creates the .cdb
+\begin_inset LatexCommand \index{<file>.cdb}
+
+\end_inset
+
+ file from the .adb
+\begin_inset LatexCommand \index{<file>.adb}
+
+\end_inset
+
+ files and the address information.
+ This .cdb is used by the debugger.
+\layout Section
+
+How the Debugger Works
+\layout Standard
+
+When the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug option is specified the compiler generates extra symbol information
+ some of which are put into the assembler source and some are put into the
+ .adb file.
+ Then the linker creates the .cdb file from the individual .adb files with
+ the address information for the symbols.
+ The debugger reads the symbolic information generated by the compiler &
+ the address information generated by the linker.
+ It uses the SIMULATOR (Daniel's S51) to execute the program, the program
+ execution is controlled by the debugger.
+ When a command is issued for the debugger, it translates it into appropriate
+ commands for the simulator.
+\layout Section
+
+Starting the Debugger
+\layout Standard
+
+The debugger can be started using the following command line.
+ (Assume the file you are debugging has the file name foo).
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb foo
+\newline
+
+\family default
+\series default
+
+\newline
+The debugger will look for the following files.
+\layout Itemize
+
+foo.c - the source file.
+\layout Itemize
+
+foo.cdb - the debugger symbol information file.
+\layout Itemize
+
+foo.ihx - the Intel hex format
+\begin_inset LatexCommand \index{Intel hex format}
+
+\end_inset
+
+ object file.
+\layout Section
+
+Command Line Options.
+\layout Itemize
+
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-directory=<source file directory> this option can used to specify the directory
+ search list.
+ The debugger will look into the directory list specified for source, cdb
+ & ihx files.
+ The items in the directory list must be separated by ':', e.g.
+ if the source files can be in the directories /home/src1 and /home/src2,
+ the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-directory option should be -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-directory=/home/src1:/home/src2.
+ Note there can be no spaces in the option.
+
+\layout Itemize
+
+-cd <directory> - change to the <directory>.
+\layout Itemize
+
+-fullname - used by GUI front ends.
+\layout Itemize
+
+-cpu <cpu-type> - this argument is passed to the simulator please see the
+ simulator docs for details.
+\layout Itemize
+
+-X <Clock frequency > this options is passed to the simulator please see
+ the simulator docs for details.
+\layout Itemize
+
+-s <serial port file> passed to simulator see the simulator docs for details.
+\layout Itemize
+
+-S <serial in,out> passed to simulator see the simulator docs for details.
+\layout Itemize
+
+-k <port number> passed to simulator see the simulator docs for details.
+\layout Section
+
+Debugger Commands.
+\layout Standard
+
+As mentioned earlier the command interface for the debugger has been deliberatel
+y kept as close the GNU debugger gdb, as possible.
+ This will help the integration with existing graphical user interfaces
+ (like ddd, xxgdb or xemacs) existing for the GNU debugger.
+ If you use a graphical user interface for the debugger you can skip the
+ next sections.
+\layout Subsubsection*
+
+break [line | file:line | function | file:function]
+\layout Standard
+
+Set breakpoint at specified line or function:
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb>break 100
+\newline
+sdcdb>break foo.c:100
+\newline
+sdcdb>break funcfoo
+\newline
+sdcdb>break foo.c:funcfoo
+\layout Subsubsection*
+
+clear [line | file:line | function | file:function ]
+\layout Standard
+
+Clear breakpoint at specified line or function:
+\newline
+
+\newline
+
+\family sans
+\series bold
+sdcdb>clear 100
+\newline
+sdcdb>clear foo.c:100
+\newline
+sdcdb>clear funcfoo
+\newline
+sdcdb>clear foo.c:funcfoo
+\layout Subsubsection*
+
+continue
+\layout Standard
+
+Continue program being debugged, after breakpoint.
+\layout Subsubsection*
+
+finish
+\layout Standard
+
+Execute till the end of the current function.
+\layout Subsubsection*
+
+delete [n]
+\layout Standard
+
+Delete breakpoint number 'n'.
+ If used without any option clear ALL user defined break points.
+\layout Subsubsection*
+
+info [break | stack | frame | registers ]
+\layout Itemize
+
+info break - list all breakpoints
+\layout Itemize
+
+info stack - show the function call stack.
+\layout Itemize
+
+info frame - show information about the current execution frame.
+\layout Itemize
+
+info registers - show content of all registers.
+\layout Subsubsection*
+
+step
+\layout Standard
+
+Step program until it reaches a different source line.
+ Note: pressing <return> repeats the last command.
+\layout Subsubsection*
+
+next
+\layout Standard
+
+Step program, proceeding through subroutine calls.
+\layout Subsubsection*
+
+run
+\layout Standard
+
+Start debugged program.
+\layout Subsubsection*
+
+ptype variable
+\layout Standard
+
+Print type information of the variable.
+\layout Subsubsection*
+
+print variable
+\layout Standard
+
+print value of variable.
+\layout Subsubsection*
+
+file filename
+\layout Standard
+
+load the given file name.
+ Note this is an alternate method of loading file for debugging.
+\layout Subsubsection*
+
+frame
+\layout Standard
+
+print information about current frame.
+\layout Subsubsection*
+
+set srcmode
+\layout Standard
+
+Toggle between C source & assembly source.
+\layout Subsubsection*
+
+! simulator command
+\layout Standard
+
+Send the string following '!' to the simulator, the simulator response is
+ displayed.
+ Note the debugger does not interpret the command being sent to the simulator,
+ so if a command like 'go' is sent the debugger can loose its execution
+ context and may display incorrect values.
+\layout Subsubsection*
+
+quit
+\layout Standard
+
+"Watch me now.
+ Iam going Down.
+ My name is Bobby Brown"
+\layout Section
+
+Interfacing with XEmacs
+\begin_inset LatexCommand \index{XEmacs}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Emacs}
+
+\end_inset
+
+.
+\layout Standard
+
+Two files (in emacs lisp) are provided for the interfacing with XEmacs,
+ sdcdb.el and sdcdbsrc.el.
+ These two files can be found in the $(prefix)/bin directory after the installat
+ion is complete.
+ These files need to be loaded into XEmacs for the interface to work.
+ This can be done at XEmacs startup time by inserting the following into
+ your '.xemacs' file (which can be found in your HOME directory):
+\newline
+
+\newline
+
+\family typewriter
+(load-file sdcdbsrc.el)
+\family default
+
+\newline
+
+\newline
+.xemacs is a lisp file so the () around the command is REQUIRED.
+ The files can also be loaded dynamically while XEmacs is running, set the
+ environment variable 'EMACSLOADPATH' to the installation bin directory
+ (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
+ To start the interface enter the following command:
+\newline
+
+\newline
+
+\family sans
+\series bold
+ESC-x sdcdbsrc
+\family default
+\series default
+
+\newline
+
+\newline
+You will prompted to enter the file name to be debugged.
+
+\newline
+
+\newline
+The command line options that are passed to the simulator directly are bound
+ to default values in the file sdcdbsrc.el.
+ The variables are listed below, these values maybe changed as required.
+\layout Itemize
+
+sdcdbsrc-cpu-type '51
+\layout Itemize
+
+sdcdbsrc-frequency '11059200
+\layout Itemize
+
+sdcdbsrc-serial nil
+\layout Standard
+
+The following is a list of key mapping for the debugger interface.
+\layout Standard
+
+\SpecialChar ~
+
+\family typewriter
+
+\newline
+;; Current Listing ::
+\newline
+;;key\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+binding\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Comment
+\newline
+;;---\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+------\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+--------
+\newline
+;;
+\newline
+;; n\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-next-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB next command
+\newline
+;; b\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-back-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB back command
+\newline
+;; c\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-cont-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB continue command
+\newline
+;; s\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-step-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB step command
+\newline
+;; ?\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-whatis-c-sexp\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB ptypecommand for data at
+\newline
+;;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ buffer point
+\newline
+;; x\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-delete\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB Delete all breakpoints if no arg
+\newline
+;;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+given or delete arg (C-u arg x)
+\newline
+;; m\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-frame\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB Display current frame if no arg,
+\newline
+;;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return asm_func(i,j);
-\newline
-}
-\newline
-
-\newline
-int main()
-\newline
-{
+\SpecialChar ~
+given or display frame arg
\newline
+;;\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\newline
-
-\newline
-
-\family default
-The corresponding assembler function is:
-\newline
-
-\newline
-
-\family typewriter
-.globl _asm_func_PARM_2
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-.globl _asm_func
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-.area OSEG
-\newline
-_asm_func_PARM_2:
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-.ds 1
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-.area CSEG
-\newline
-_asm_func:
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov a,dpl
+\SpecialChar ~
+buffer point
\newline
+;; !\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-add a,_asm_func_PARM_2
-\newline
+\SpecialChar ~
+ sdcdbsrc-goto-sdcdb\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov dpl,a
+\SpecialChar ~
+Goto the SDCDB output buffer
\newline
+;; p\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov dpl
-\begin_inset LatexCommand \index{DPTR, DPH, DPL}
-
-\end_inset
-
-,#0x00
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ sdcdb-print-c-sexp\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-ret
-\newline
-
-\newline
-
-\family default
-Note here that the return values are placed in 'dpl' - One byte return value,
- 'dpl' LSB & 'dph' MSB for two byte values.
- 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
-b' & 'acc' for four byte values.
-\layout Standard
-
-The parameter naming convention is _<function_name>_PARM_<n>, where n is
- the parameter number starting from 1, and counting from the left.
- The first parameter is passed in
-\begin_inset Quotes eld
-\end_inset
-
-dpl
-\begin_inset Quotes erd
-\end_inset
-
- for One bye parameter,
-\begin_inset Quotes eld
-\end_inset
-
-dptr
-\begin_inset Quotes erd
-\end_inset
-
- if two bytes,
-\begin_inset Quotes eld
-\end_inset
-
-b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for three bytes and
-\begin_inset Quotes eld
-\end_inset
-
-acc,b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for four bytes, the varible name for the second parameter will be _<function_na
-me>_PARM_2.
-\newline
-
-\newline
-Assemble the assembler routine with the following command:
-\newline
-
-\newline
-
-\family sans
-\series bold
-asx8051 -losg asmfunc.asm
-\newline
-
-\newline
-
-\family default
-\series default
-Then compile and link the assembler routine to the C source file with the
- following command:
-\newline
-
-\newline
-
-\family sans
-\series bold
-sdcc cfunc.c asmfunc.rel
-\layout Subsubsection
-
-Assembler Routine(reentrant
-\begin_inset LatexCommand \index{reentrant}
-
-\end_inset
-
-)
-\begin_inset LatexCommand \index{Assembler routines (reentrant)}
-
-\end_inset
-
-
-\layout Standard
-
-In this case the second parameter onwards will be passed on the stack, the
- parameters are pushed from right to left i.e.
- after the call the left most parameter will be on the top of the stack.
- Here is an example:
-\newline
-
-\newline
-
-\family typewriter
-extern int asm_func(unsigned char, unsigned char);
-\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB print command for data at
\newline
-int c_func (unsigned char i, unsigned char j) reentrant
+;;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ buffer point
\newline
-{
+;; g\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-goto-sdcdb\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Goto the SDCDB output buffer
\newline
+;; t\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-mode\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return asm_func(i,j);
-\newline
-}
-\newline
-
-\newline
-int main()
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Toggles Sdcdbsrc mode (turns it off)
\newline
-{
+;;
\newline
+;; C-c C-f\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\newline
-
-\family default
-
-\newline
-The corresponding assembler routine is:
-\newline
-
-\newline
-
-\family typewriter
-.globl _asm_func
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-finish-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB finish command
\newline
-_asm_func:
+;;
\newline
+;; C-x SPC\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-push _bp
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ sdcdb-break\SpecialChar ~
\SpecialChar ~
-mov _bp,sp
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov r2,dpl
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov a,_bp
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-clr c
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-add a,#0xfd
+Set break for line with point
\newline
+;; ESC t\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov r0,a
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-add a,#0xfc
-\newline
\SpecialChar ~
+ sdcdbsrc-mode\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov r1,a
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov a,@r0
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Toggle Sdcdbsrc mode
\newline
+;; ESC m\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-srcmode\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-add a,r2
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ Toggle list mode
+\newline
+;;
+\newline
+
+\layout Chapter
+\pagebreak_top
+TIPS
+\layout Standard
+
+Here are a few guidelines that will help the compiler generate more efficient
+ code, some of the tips are specific to this compiler others are generally
+ good programming practice.
+\layout Itemize
+
+Use the smallest data type to represent your data-value.
+ If it is known in advance that the value is going to be less than 256 then
+ use an 'unsigned char' instead of a 'short' or 'int'.
+ Please note, that ANSI C requires both signed and unsigned chars to be
+ promoted to 'signed int' before doing any operation.
+ This promotion can be omitted, if the result is the same.
+ The effect of the promotion rules together with the sign-extension is often
+ supprising:
+\begin_deeper
+\layout Verse
+
+
+\family typewriter
+unsigned char uc = 0xfe;
+\newline
+if (uc * uc < 0) /* this is true! */
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov dpl,a
+....
+\newline
+}
+\layout Standard
+
+
+\family typewriter
+uc * uc
+\family default
+ is evaluated as
+\family typewriter
+(int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
+\family default
+.
+
+\newline
+Another one:
+\layout Verse
+
+
+\family typewriter
+(unsigned char) -12 / (signed char) -3 = ...
+\layout Standard
+
+No, the result is not 4:
+\layout Verse
+
+
+\family typewriter
+(int) (unsigned char) -12 / (int) (signed char) -3 =
+\newline
+(int) (unsigned char) 0xf4 / (int) (signed char) 0xfd =
+\newline
+(int) 0x00f4 / (int) 0xfffd =
+\newline
+(int) 0x00f4 / (int) 0xfffd =
+\newline
+(int) 244 / (int) -3 =
+\newline
+(int) -81 = (int) 0xffaf;
+\layout Standard
+
+Don't complain, that gcc gives you a different result.
+ gcc uses 32 bit ints, while SDCC uses 16 bit ints.
+ Therefore the results are different.
+\newline
+From
+\begin_inset Quotes sld
+\end_inset
+
+comp.lang.c FAQ
+\begin_inset Quotes srd
+\end_inset
+
+:
+\layout Quote
+
+If well-defined overflow characteristics are important and negative values
+ are not, or if you want to steer clear of sign-extension problems when
+ manipulating bits or bytes, use one of the corresponding unsigned types.
+ (Beware when mixing signed and unsigned values in expressions, though.)
+\newline
+Although character types (especially unsigned char) can be used as "tiny"
+ integers, doing so is sometimes more trouble than it's worth, due to unpredicta
+ble sign extension and increased code size.
+\end_deeper
+\layout Itemize
+
+Use unsigned when it is known in advance that the value is not going to
+ be negative.
+ This helps especially if you are doing division or multiplication, bit-shifting
+ or are using an array index.
+\layout Itemize
+
+NEVER jump into a LOOP.
+\layout Itemize
+
+Declare the variables to be local
+\begin_inset LatexCommand \index{local variables}
+
+\end_inset
+
+ whenever possible, especially loop control variables (induction).
+\layout Itemize
+
+Since the compiler does not always do implicit integral promotion, the programme
+r should do an explicit cast when integral promotion is required.
+\layout Itemize
+
+Reducing the size of division, multiplication & modulus operations can reduce
+ code size substantially.
+ Take the following code for example.
+\begin_deeper
+\layout Verse
+
+
+\family typewriter
+foobar(unsigned int p1, unsigned char ch)
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov dph,#0x00
+unsigned char ch1 = p1 % ch ;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov sp,_bp
+....
+\newline
+}
+\layout Standard
+
+For the modulus operation the variable ch will be promoted to unsigned int
+ first then the modulus operation will be performed (this will lead to a
+ call to support routine _moduint()), and the result will be casted to a
+ char.
+ If the code is changed to
+\layout Verse
+
+
+\family typewriter
+foobar(unsigned int p1, unsigned char ch)
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-pop _bp
+unsigned char ch1 = (unsigned char)p1 % ch ;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-ret
+....
\newline
+}
+\layout Standard
+
+It would substantially reduce the code generated (future versions of the
+ compiler will be smart enough to detect such optimization opportunities).
+\end_deeper
+\layout Itemize
+
+Have a look at the assembly listing to get a
+\begin_inset Quotes sld
+\end_inset
+
+feeling
+\begin_inset Quotes srd
+\end_inset
+
+ for the code generation.
+\layout Section
+
+Tools
+\begin_inset LatexCommand \index{Tools}
+
+\end_inset
+
+ included in the distribution
+\layout Standard
+\align center
+
+\begin_inset Tabular
+<lyxtabular version="3" rows="12" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0pt">
+<column alignment="center" valignment="top" leftline="true" width="0pt">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Name
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Purpose
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Directory
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+uCsim
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\family default
-The compiling and linking procedure remains the same, however note the extra
- entry & exit linkage required for the assembler code, _bp is the stack
- frame pointer and is used to compute the offset into the stack for parameters
- and local variables.
-\layout Subsection
+Simulator for various architectures
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-External Stack
-\begin_inset LatexCommand \index{stack}
+\layout Standard
+sdcc/sim/ucsim
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+keil2sdcc.pl
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\begin_inset LatexCommand \index{External stack}
+\layout Standard
+header file conversion
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-The external stack is located at the start of the external ram segment,
- and is 256 bytes in size.
- When -
-\begin_inset ERT
-status Collapsed
+mh2h.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+header file conversion
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
--xstack option is used to compile the program, the parameters and local
- variables of all reentrant functions are allocated in this area.
- This option is provided for programs with large stack space requirements.
- When used with the -
-\begin_inset ERT
-status Collapsed
+\layout Standard
+
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+as-gbz80
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--stack-auto option, all parameters and local variables are allocated on
- the external stack (note support libraries will need to be recompiled with
- the same options).
\layout Standard
-The compiler outputs the higher order address byte of the external ram segment
- into PORT P2, therefore when using the External Stack option, this port
- MAY NOT be used by the application program.
-\layout Subsection
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-ANSI-Compliance
-\begin_inset LatexCommand \index{ANSI-compliance}
+\layout Standard
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+as-z80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-Deviations from the compliancy.
-\layout Itemize
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-functions are not always reentrant.
-\layout Itemize
+\layout Standard
-structures cannot be assigned values directly, cannot be passed as function
- parameters or assigned to each other and cannot be a return value from
- a function, e.g.:
-\family typewriter
-\newline
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-struct s { ...
- };
-\newline
-struct s s1, s2;
-\newline
-foo()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-}
-\newline
-struct s foo1 (struct s parms) /* is invalid in SDCC although allowed in
- ANSI */
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-struct s rets;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return rets;/* is invalid in SDCC although allowed in ANSI */
-\newline
-}
-\layout Itemize
+\layout Standard
+
+asx8051
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcdb
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-'long long
-\begin_inset LatexCommand \index{long long (not supported)}
+\layout Standard
+aslink
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-' (64 bit integers
-\begin_inset LatexCommand \index{int (64 bit) (not supported)}
+\layout Standard
+Linker
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-) not supported.
-\layout Itemize
+\layout Standard
-'double
-\begin_inset LatexCommand \index{double (not supported)}
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-' precision floating point
-\begin_inset LatexCommand \index{Floating point support}
+\layout Standard
+link-z80
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-not supported.
-\layout Itemize
+\layout Standard
-No support for setjmp and longjmp (for now).
-\layout Itemize
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Old K&R style
-\begin_inset LatexCommand \index{K\&R style}
+\layout Standard
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- function declarations are NOT allowed.
-\newline
+\layout Standard
-\family typewriter
+link-gbz80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-foo(i,j) /* this old style of function declarations */
-\newline
-int i,j; /* are valid in ANSI but not valid in SDCC */
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-}
-\layout Itemize
+\layout Standard
-functions declared as pointers must be dereferenced during the call.
-\newline
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family typewriter
+\layout Standard
-\newline
-int (*foo)();
-\newline
-...
-
-\newline
-/* has to be called like this */
-\newline
-(*foo)(); /* ansi standard allows calls to be made like 'foo()' */
-\layout Subsection
-Cyclomatic Complexity
-\begin_inset LatexCommand \index{Cyclomatic complexity}
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+packihx
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+\layout Standard
+
+ihx packer
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-Cyclomatic complexity of a function is defined as the number of independent
- paths the program can take during execution of the function.
- This is an important number since it defines the number test cases you
- have to generate to validate the function.
- The accepted industry standard for complexity number is 10, if the cyclomatic
- complexity reported by SDCC exceeds 10 you should think about simplification
- of the function logic.
- Note that the complexity level is not related to the number of lines of
- code in a function.
- Large functions can have low complexity, and small functions can have large
- complexity levels.
-
-\newline
-\newline
-SDCC uses the following formula to compute the complexity:
-\newline
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+</lyxtabular>
-\layout Standard
+\end_inset
-complexity = (number of edges in control flow graph) - (number of nodes
- in control flow graph) + 2;
-\newline
\newline
-Having said that the industry standard is 10, you should be aware that in
- some cases it be may unavoidable to have a complexity level of less than
- 10.
- For example if you have switch statement with more than 10 case labels,
- each case label adds one to the complexity level.
- The complexity level is by no means an absolute measure of the algorithmic
- complexity of the function, it does however provide a good starting point
- for which functions you might look at for further optimization.
+
\layout Section
-\pagebreak_top
-TIPS
-\layout Standard
-Here are a few guidelines that will help the compiler generate more efficient
- code, some of the tips are specific to this compiler others are generally
- good programming practice.
-\layout Itemize
+Documentation
+\begin_inset LatexCommand \index{Documentation}
-Use the smallest data type to represent your data-value.
- If it is known in advance that the value is going to be less than 256 then
- use an 'unsigned char' instead of a 'short' or 'int'.
-\layout Itemize
+\end_inset
-Use unsigned when it is known in advance that the value is not going to
- be negative.
- This helps especially if you are doing division or multiplication.
-\layout Itemize
+ included in the distribution
+\layout Standard
+\align center
-NEVER jump into a LOOP.
-\layout Itemize
+\begin_inset Tabular
+<lyxtabular version="3" rows="10" columns="2">
+<features>
+<column alignment="left" valignment="top" leftline="true" width="0">
+<column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-Declare the variables to be local whenever possible, especially loop control
- variables (induction).
-\layout Itemize
+\layout Standard
-Since the compiler does not always do implicit integral promotion, the programme
-r should do an explicit cast when integral promotion is required.
-\layout Itemize
+Subject / Title
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Reducing the size of division, multiplication & modulus operations can reduce
- code size substantially.
- Take the following code for example.
-\family typewriter
+\layout Standard
-\newline
+Where to get / filename
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-foobar(unsigned int p1, unsigned char ch)
-\newline
-{
-\newline
- unsigned char ch1 = p1 % ch ;
-\newline
- ....
-
-\newline
-}
-\newline
+\layout Standard
-\family default
+SDCC Compiler User Guide
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-For the modulus operation the variable ch will be promoted to unsigned int
- first then the modulus operation will be performed (this will lead to a
- call to support routine _moduint()), and the result will be casted to a
- char.
- If the code is changed to
-\newline
+\layout Standard
+
+You're reading it right now
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
+\layout Standard
-\newline
-foobar(unsigned int p1, unsigned char ch)
-\newline
-{
-\newline
- unsigned char ch1 = (unsigned char)p1 % ch ;
-\newline
- ....
-
-\newline
-}
-\newline
+Changelog of SDCC
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family default
+\layout Standard
-\newline
-It would substantially reduce the code generated (future versions of the
- compiler will be smart enough to detect such optimization oppurtunities).
-\layout Subsection
+sdcc/Changelog
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-Notes on MCS51 memory
-\begin_inset LatexCommand \index{MCS51 memory}
+\layout Standard
+ASXXXX Assemblers and ASLINK Relocating Linker
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- layout
\layout Standard
-The 8051 family of micro controller have a minimum of 128 bytes of internal
- memory which is structured as follows
-\newline
+sdcc/as/doc/asxhtm.html
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-- Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R7 to R7
-
-\newline
-- Bytes 20-2F - 16 bytes to hold 128 bit variables and
-\newline
-- Bytes 30-7F - 60 bytes for general purpose use.
-\newline
+\layout Standard
-\newline
-Normally the SDCC compiler will only utilise the first bank
-\begin_inset LatexCommand \index{bank}
+SDCC regression test
+\begin_inset LatexCommand \index{Regression test}
\end_inset
- of registers, but it is possible to specify that other banks of registers
- should be used in interrupt
-\begin_inset LatexCommand \index{interrupt}
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- routines.
- By default, the compiler will place the stack after the last bank of used
- registers, i.e.
- if the first 2 banks of registers are used, it will position the base of
- the internal stack at address 16 (0X10).
- This implies that as the stack
-\begin_inset LatexCommand \index{stack}
+\layout Standard
+sdcc/doc/test_suite_spec.pdf
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- grows, it will use up the remaining register banks, and the 16 bytes used
- by the 128 bit variables, and 60 bytes for general purpose use.
\layout Standard
-By default, the compiler uses the 60 general purpose bytes to hold "near
- data".
- The compiler/optimiser may also declare some Local Variables in this area
- to hold local data.
-
-\layout Standard
+Various notes
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-If any of the 128 bit variables are used, or near data is being used then
- care needs to be taken to ensure that the stack does not grow so much that
- it starts to over write either your bit variables or "near data".
- There is no runtime checking to prevent this from happening.
\layout Standard
-The amount of stack being used is affected by the use of the "internal stack"
- to save registers before a subroutine call is made (-
-\begin_inset ERT
-status Collapsed
+sdcc/doc/*
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+Notes on debugging with sdcdb
+\begin_inset LatexCommand \index{sdcdb (debugger)}
+
\end_inset
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- will declare parameters and local variables on the stack) and the number
- of nested subroutines.
\layout Standard
-If you detect that the stack is over writing you data, then the following
- can be done.
- -
-\begin_inset ERT
-status Collapsed
+sdcc/debugger/README
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+Software simulator for microcontrollers
\end_inset
-
--xstack will cause an external stack to be used for saving registers and
- (if -
-\begin_inset ERT
-status Collapsed
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/sim/ucsim/doc
+\family default
+\series default
+\shape default
+\size default
+\emph default
+\bar default
+\noun default
+\color default
+/index.html
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--stack-auto is being used) storing parameters and local variables.
- However this will produce more code which will be slower to execute.
-
\layout Standard
--
-\begin_inset ERT
-status Collapsed
+Temporary notes on the pic16
+\begin_inset LatexCommand \index{PIC16}
-\layout Standard
+\end_inset
-\backslash
-/
+ port
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
--stack-loc
-\begin_inset LatexCommand \index{-\/-stack-loc}
+\layout Standard
+sdcc/src/pic16/NOTES
\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- will allow you specify the start of the stack, i.e.
- you could start it after any data in the general purpose area.
- However this may waste the memory not used by the register banks and if
- the size of the "near data" increases, it may creep into the bottom of
- the stack.
\layout Standard
--
-\begin_inset ERT
-status Collapsed
+SDCC internal documentation (debugging file format)
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+sdcc/doc/
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+cdbfileformat.pd
+\family default
+\series default
+\shape default
+\size default
+\emph default
+\bar default
+\noun default
+\color default
+f
\end_inset
-
--data-loc
-\begin_inset LatexCommand \index{-\/-data-loc}
+</cell>
+</row>
+</lyxtabular>
\end_inset
- allows you to specify the start address of the near data.
- This could be used to move the "near data" further away from the stack
- giving it more room to grow.
- This will only work if no bit variables are being used and the stack can
- grow to use the bit variable space.
-\newline
-\newline
-Conclusion.
\newline
-\newline
-If you find that the stack is over writing your bit variables or "near data"
- then the approach which best utilised the internal memory is to position
- the "near data" after the last bank of used registers or, if you use bit
- variables, after the last bit variable by using the -
-\begin_inset ERT
-status Collapsed
+\layout Section
+
+Related open source tools
+\begin_inset LatexCommand \index{Related tools}
+
+\end_inset
+
\layout Standard
+\align center
-\backslash
-/
+\begin_inset Tabular
+<lyxtabular version="3" rows="11" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0pt">
+<column alignment="block" valignment="top" leftline="true" width="30line%">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Name
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--data-loc, e.g.
- if two register banks are being used and no bit variables, -
-\begin_inset ERT
-status Collapsed
+\layout Standard
+
+Purpose
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
\layout Standard
-\backslash
-/
+Where to get
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
--data-loc 16.
\layout Standard
-If bit variables are being used, another method would be to try and squeeze
- the data area in the unused register banks if it will fit, and start the
- stack after the last bit variable.
-\layout Subsection
+gpsim
+\begin_inset LatexCommand \index{gpsim (pic simulator)}
+
+\end_inset
-Tools
-\begin_inset LatexCommand \index{Tools}
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PIC simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- included in the distribution
\layout Standard
-\begin_inset Tabular
-<lyxtabular version="3" rows="9" columns="3">
-<features>
-<column alignment="center" valignment="top" leftline="true" width="0pt">
-<column alignment="center" valignment="top" leftline="true" width="0pt">
-<column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
-<row topline="true" bottomline="true">
+\begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
+
+\end_inset
+
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-Name
+gputils
+\begin_inset LatexCommand \index{gputils (pic tools)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Purpose
+GNU PIC utilities
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-Directory
+
+\begin_inset LatexCommand \url{http://gputils.sourceforge.net/}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-uCsim
+flP5
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Simulator for various architectures
+PIC programmer
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-sdcc/sim/ucsim
+
+\begin_inset LatexCommand \url{http://digilander.libero.it/fbradasc/FLP5.html}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-keil2sdcc.pl
+indent
+\begin_inset LatexCommand \index{indent (source formatting tool)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-header file conversion
+Formats C source - Master of the white spaces
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-sdcc/support/scripts
+
+\begin_inset LatexCommand \url{http://home.hccnet.nl/d.ingamells/beautify.html}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-mh2h.c
+srecord
+\begin_inset LatexCommand \index{srecord (tool)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-header file conversion
+Object file conversion, checksumming, ...
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-sdcc/support/scripts
+
+\begin_inset LatexCommand \url{http://srecord.sourceforge.net/}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-as-gbz80
+objdump
+\begin_inset LatexCommand \index{objdump (tool)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Assembler
+Object file conversion, ...
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-
-\family roman
-\series medium
-\shape up
-\size normal
-\emph off
-\bar no
-\noun off
-\color none
-sdcc/bin
+Part of binutils (should be there anyway)
\end_inset
</cell>
</row>
\layout Standard
-as-z80
+doxygen
+\begin_inset LatexCommand \index{doxygen (source documentation tool)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Assembler
+Source code documentation system
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-\family roman
-\series medium
-\shape up
-\size normal
-\emph off
-\bar no
-\noun off
-\color none
-sdcc/bin
+\begin_inset LatexCommand \url{http://www.doxygen.org}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-asx8051
+kdevelop
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Assembler
+IDE (has anyone tried integrating SDCC & sdcdb? Unix only)
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-\family roman
-\series medium
-\shape up
-\size normal
-\emph off
-\bar no
-\noun off
-\color none
-sdcc/bin
+\begin_inset LatexCommand \url{http://www.kdevelop.org}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
-sdcdb
+splint
+\begin_inset LatexCommand \index{splint (syntax checking tool)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Simulator
+Statically checks c sources
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-\family roman
-\series medium
-\shape up
-\size normal
-\emph off
-\bar no
-\noun off
-\color none
-sdcc/bin
+\begin_inset LatexCommand \url{http://www.splint.org}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\layout Standard
+ddd
+\begin_inset LatexCommand \index{ddd (debugger)}
+
+\end_inset
+
+
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
+Debugger, serves nicely as GUI to sdcdb
+\begin_inset LatexCommand \index{sdcdb (debugger)}
+
+\end_inset
+
+ (Unix only)
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
+
+\begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
+
+\end_inset
+
+
\end_inset
</cell>
</row>
\end_inset
-\layout Subsection
-
-Related open source tools
-\begin_inset LatexCommand \index{Related tools}
-
-\end_inset
+\newline
+\layout Section
+Related documentation / recommended reading
\layout Standard
-
+\align center
\begin_inset Tabular
-<lyxtabular version="3" rows="5" columns="3">
+<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="center" valignment="top" leftline="true" width="0pt">
-<column alignment="center" valignment="top" leftline="true" width="0pt">
+<column alignment="block" valignment="top" leftline="true" width="30line%">
<column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Purpose
+Subject / Title
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-gpsim
-\begin_inset LatexCommand \index{gpsim}
-
-\end_inset
-
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+c-refcard.pdf
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-PIC simulator
+C Reference Card
+\begin_inset LatexCommand \index{C Reference card}
+
+\end_inset
+
+, 2 pages
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-\begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
+\begin_inset LatexCommand \url{http://www.refcards.com/about/c.html}
\end_inset
\layout Standard
-srecord
-\begin_inset LatexCommand \index{srecord}
-
-\end_inset
-
-
+c-faq
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Object file conversion, checksumming, ...
+C-FAQ-list
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-\begin_inset LatexCommand \url{http://srecord.sourceforge.net/}
+\begin_inset LatexCommand \url{http://www.eskimo.com/~scs/C-faq/top.html}
\end_inset
\layout Standard
-objdump
-\begin_inset LatexCommand \index{objdump}
-
-\end_inset
-
-
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Object file conversion
+Latest datasheet of the target CPU
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-Part of binutils (should be there anyway)
+vendor
\end_inset
</cell>
</row>
-<row topline="true" bottomline="true">
+<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-ddd
-\begin_inset LatexCommand \index{ddd}
-
-\end_inset
-
-
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Debugger, serves nicely as GUI to sdcdb
-\begin_inset LatexCommand \index{sdcdb}
-
-\end_inset
-
-
+Revision history of datasheet
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-
-\begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
-
-\end_inset
-
-
+vendor
\end_inset
</cell>
</row>
-</lyxtabular>
-
-\end_inset
-
-
-\layout Subsection
-
-Related documentation / recommended reading
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="4" columns="3">
-<features>
-<column alignment="center" valignment="top" leftline="true" width="0pt">
-<column alignment="center" valignment="top" leftline="true" width="0pt">
-<column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-Name
+S.
+ S.
+ Muchnick
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-Subject
+Advanced Compiler Design and Implementation
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-Where to get
+bookstore (very dedicated, probably read other books first)
\end_inset
</cell>
</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+</lyxtabular>
+\end_inset
+
+
+\newline
+
+\layout Section
+
+Some Questions
\layout Standard
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+Some questions answered, some pointers given - it might be time to in turn
+ ask
+\emph on
+you
+\emph default
+ some questions:
+\layout Itemize
+
+can you solve your project with the selected microcontroller? Would you
+ find out early or rather late that your target is too small/slow/whatever?
+ Can you switch to a slightly better device if it doesn't fit?
+\layout Itemize
+
+should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
+ and/or another programming language be more adequate? Would an operating
+ system on the target device help?
+\layout Itemize
+
+if you solved the problem, will the marketing department be happy?
+\layout Itemize
+
+if the marketing department is happy, will customers be happy?
+\layout Itemize
+
+if you're the project manager, marketing department and maybe even the customer
+ in one person, have you tried to see the project from the outside?
+\layout Itemize
+
+is the project done if you think it is done? Or is just that other interface/pro
+tocol/feature/configuration/option missing? How about website, manual(s),
+ internationali(z|s)ation, packaging, labels, 2nd source for components,
+ electromagnetic compatability/interference, documentation for production,
+ production test software, update mechanism, patent issues?
+\layout Itemize
+
+is your project adequately positioned in that magic triangle: fame, fortune,
+ fun?
+\layout Standard
+
+Maybe not all answers to these questions are known and some answers may
+ even be
+\emph on
+no
+\emph default
+, nevertheless knowing these questions may help you to avoid burnout
+\begin_inset Foot
+collapsed false
\layout Standard
-Compiler architecture
+burnout is bad for electronic devices, programmers and motorcycle tyres
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+.
+ Chances are you didn't want to hear some of them...
+\layout Chapter
+
+Support
+\begin_inset LatexCommand \index{Support}
-bookstore
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
-test_suite_spec.pdf
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+\layout Standard
+SDCC has grown to be a large project.
+ The compiler alone (without the preprocessor, assembler and linker) is
+ well over 100,000 lines of code (blank stripped).
+ The open source nature of this project is a key to its continued growth
+ and support.
+ You gain the benefit and support of many active software developers and
+ end users.
+ Is SDCC perfect? No, that's why we need your help.
+ The developers take pride in fixing reported bugs.
+ You can help by reporting the bugs and helping other SDCC users.
+ There are lots of ways to contribute, and we encourage you to take part
+ in making SDCC a great software package.
+
\layout Standard
-sdcc regression test
+The SDCC project is hosted on the SDCC sourceforge site at
+\begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
+
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+.
+ You'll find the complete set of mailing lists
+\begin_inset LatexCommand \index{Mailing list}
-sdcc/doc
\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+, forums, bug reporting system, patch submission
+\begin_inset LatexCommand \index{Patch submission}
+\end_inset
+
+ system, download
+\begin_inset LatexCommand \index{download}
-\family roman
-\series medium
-\shape up
-\size normal
-\emph off
-\bar no
-\noun off
-\color none
-cdbfileformat.pd
-\family default
-\series default
-\shape default
-\size default
-\emph default
-\bar default
-\noun default
-\color default
-f
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ area and cvs code repository
+\begin_inset LatexCommand \index{cvs code repository}
-sdcc internal documentation
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ there.
+\layout Section
+
+Reporting Bugs
+\begin_inset LatexCommand \index{Bug reporting}
-sdcc/doc
\end_inset
-</cell>
-</row>
-</lyxtabular>
+
+
+\begin_inset LatexCommand \index{Reporting bugs}
\end_inset
-\layout Section
-\pagebreak_top
-Retargetting for other MCUs.
\layout Standard
-The issues for retargetting the compiler are far too numerous to be covered
- by this document.
- What follows is a brief description of each of the seven phases of the
- compiler and its MCU dependency.
-\layout Itemize
-
-Parsing the source and building the annotated parse tree.
- This phase is largely MCU independent (except for the language extensions).
- Syntax & semantic checks are also done in this phase, along with some initial
- optimizations like back patching labels and the pattern matching optimizations
- like bit-rotation etc.
-\layout Itemize
+The recommended way of reporting bugs is using the infrastructure of the
+ sourceforge site.
+ You can follow the status of bug reports there and have an overview about
+ the known bugs.
+\layout Standard
-The second phase involves generating an intermediate code which can be easy
- manipulated during the later phases.
- This phase is entirely MCU independent.
- The intermediate code generation assumes the target machine has unlimited
- number of registers, and designates them with the name iTemp.
- The compiler can be made to dump a human readable form of the code generated
- by using the -
+Bug reports are automatically forwarded to the developer mailing list and
+ will be fixed ASAP.
+ When reporting a bug, it is very useful to include a small test program
+ (the smaller the better) which reproduces the problem.
+ If you can isolate the problem by looking at the generated assembly code,
+ this can be very helpful.
+ Compiling your program with the -
\begin_inset ERT
status Collapsed
/
\end_inset
--dumpraw option.
-\layout Itemize
+-dumpall
+\begin_inset LatexCommand \index{-\/-dumpall}
-This phase does the bulk of the standard optimizations and is also MCU independe
-nt.
- This phase can be broken down into several sub-phases:
-\newline
+\end_inset
-\newline
-Break down intermediate code (iCode) into basic blocks.
-\newline
-Do control flow & data flow analysis on the basic blocks.
-\newline
-Do local common subexpression elimination, then global subexpression elimination
-\newline
-Dead code elimination
-\newline
-Loop optimizations
-\newline
-If loop optimizations caused any changes then do 'global subexpression eliminati
-on' and 'dead code elimination' again.
-\layout Itemize
+ option can sometimes be useful in locating optimization problems.
+ When reporting a bug please maker sure you:
+\layout Enumerate
-This phase determines the live-ranges; by live range I mean those iTemp
- variables defined by the compiler that still survive after all the optimization
-s.
- Live range analysis
-\begin_inset LatexCommand \index{Live range analysis}
+Attach the code you are compiling with SDCC.
+
+\layout Enumerate
-\end_inset
+Specify the exact command you use to run SDCC, or attach your Makefile.
+
+\layout Enumerate
- is essential for register allocation, since these computation determines
- which of these iTemps will be assigned to registers, and for how long.
-\layout Itemize
+Specify the SDCC version (type "
+\family sans
+\series bold
+sdcc -v
+\family default
+\series default
+"), your platform, and operating system.
+
+\layout Enumerate
-Phase five is register allocation.
- There are two parts to this process.
-\newline
+Provide an exact copy of any error message or incorrect output.
+
+\layout Enumerate
-\newline
-The first part I call 'register packing' (for lack of a better term).
- In this case several MCU specific expression folding is done to reduce
- register pressure.
-\newline
+Put something meaningful in the subject of your message.
+\layout Standard
-\newline
-The second part is more MCU independent and deals with allocating registers
- to the remaining live ranges.
- A lot of MCU specific code does creep into this phase because of the limited
- number of index registers available in the 8051.
-\layout Itemize
+Please attempt to include these 5 important parts, as applicable, in all
+ requests for support or when reporting any problems or bugs with SDCC.
+ Though this will make your message lengthy, it will greatly improve your
+ chance that SDCC users and developers will be able to help you.
+ Some SDCC developers are frustrated by bug reports without code provided
+ that they can use to reproduce and ultimately fix the problem, so please
+ be sure to provide sample code if you are reporting a bug!
+\layout Standard
-The Code generation phase is (unhappily), entirely MCU dependent and very
- little (if any at all) of this code can be reused for other MCU.
- However the scheme for allocating a homogenized assembler operand for each
- iCode operand may be reused.
-\layout Itemize
+Please have a short check that you are using a recent version of SDCC and
+ the bug is not yet known.
+ This is the link for reporting bugs:
+\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
-As mentioned in the optimization section the peep-hole optimizer is rule
- based system, which can reprogrammed for other MCUs.
+\end_inset
+
+.
\layout Section
-\pagebreak_top
-SDCDB
-\begin_inset LatexCommand \index{sdcdb}
+
+Requesting Features
+\begin_inset LatexCommand \label{sub:Requesting-Features}
\end_inset
- - Source Level Debugger
-\begin_inset LatexCommand \index{Debugger}
-\end_inset
+\begin_inset LatexCommand \index{Feature request}
+\end_inset
-\layout Standard
-SDCC is distributed with a source level debugger.
- The debugger uses a command line interface, the command repertoire of the
- debugger has been kept as close to gdb
-\begin_inset LatexCommand \index{gdb}
+\begin_inset LatexCommand \index{Requesting features}
\end_inset
- (the GNU debugger) as possible.
- The configuration and build process is part of the standard compiler installati
-on, which also builds and installs the debugger in the target directory
- specified during configuration.
- The debugger allows you debug BOTH at the C source and at the ASM source
- level.
-\layout Subsection
-Compiling for Debugging
\layout Standard
-The \SpecialChar \-
-\SpecialChar \-
-debug option must be specified for all files for which debug information
- is to be generated.
- The complier generates a .adb file for each of these files.
- The linker creates the .cdb file from the .adb files and the address information.
- This .cdb is used by the debugger.
-\layout Subsection
+Like bug reports feature requests are forwarded to the developer mailing
+ list.
+ This is the link for requesting features:
+\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
-How the Debugger Works
-\layout Standard
+\end_inset
-When the -
-\begin_inset ERT
-status Collapsed
+.
+\layout Section
+Submitting patches
\layout Standard
-\backslash
-/
-\end_inset
+Like bug reports contributed patches are forwarded to the developer mailing
+ list.
+ This is the link for submitting patches
+\begin_inset LatexCommand \index{Patch submission}
--debug option is specified the compiler generates extra symbol information
- some of which are put into the the assembler source and some are put into
- the .adb file.
- Then the linker creates the .cdb file from the individual .adb files with
- the address information for the symbols.
- The debugger reads the symbolic information generated by the compiler &
- the address information generated by the linker.
- It uses the SIMULATOR (Daniel's S51) to execute the program, the program
- execution is controlled by the debugger.
- When a command is issued for the debugger, it translates it into appropriate
- commands for the simulator.
-\layout Subsection
+\end_inset
-Starting the Debugger
-\layout Standard
+:
+\begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}
-The debugger can be started using the following command line.
- (Assume the file you are debugging has the file name foo).
-\newline
+\end_inset
-\newline
+.
+\layout Standard
+You need to specify some parameters to the
+\family typewriter
+diff
+\family default
+ command for the patches to be useful.
+ If you modified more than one file a patch created f.e.
+ with
\family sans
\series bold
-sdcdb foo
-\newline
-
-\family default
-\series default
-\newline
-The debugger will look for the following files.
-\layout Itemize
+\begin_inset Quotes sld
+\end_inset
-foo.c - the source file.
-\layout Itemize
+diff -Naur unmodified_directory modified_directory >my_changes.patch
+\begin_inset Quotes srd
+\end_inset
-foo.cdb - the debugger symbol information file.
-\layout Itemize
-foo.ihx - the intel hex format
-\begin_inset LatexCommand \index{Intel hex format}
+\family default
+\series default
+ will be fine, otherwise
+\family sans
+\series bold
+\begin_inset Quotes sld
\end_inset
- object file.
-\layout Subsection
+diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
+\begin_inset Quotes srd
+\end_inset
-Command Line Options.
-\layout Itemize
--
-\begin_inset ERT
-status Collapsed
+\series default
+
+\family default
+will do.
+\layout Section
+Getting Help
\layout Standard
-\backslash
-/
+These links should take you directly to the
+\begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
+
\end_inset
--directory=<source file directory> this option can used to specify the directory
- search list.
- The debugger will look into the directory list specified for source, cdb
- & ihx files.
- The items in the directory list must be separated by ':', e.g.
- if the source files can be in the directories /home/src1 and /home/src2,
- the -
-\begin_inset ERT
-status Collapsed
+
+\begin_inset Foot
+collapsed false
\layout Standard
-\backslash
-/
+Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
+ automated messages (mid 2003)
\end_inset
--directory option should be -
-\begin_inset ERT
-status Collapsed
+ and the
+\begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
+
+\end_inset
+
+, lists and forums are archived and searchable so if you are lucky someone
+ already had a similar problem.
+\layout Section
+ChangeLog
\layout Standard
-\backslash
-/
+You can follow the status of the cvs version
+\begin_inset LatexCommand \index{version}
+
\end_inset
--directory=/home/src1:/home/src2.
- Note there can be no spaces in the option.
-
-\layout Itemize
+ of SDCC by watching the Changelog
+\begin_inset LatexCommand \index{Changelog}
--cd <directory> - change to the <directory>.
-\layout Itemize
+\end_inset
--fullname - used by GUI front ends.
-\layout Itemize
+ in the cvs-repository
+\newline
--cpu <cpu-type> - this argument is passed to the simulator please see the
- simulator docs for details.
-\layout Itemize
+\size footnotesize
--X <Clock frequency > this options is passed to the simulator please see
- the simulator docs for details.
-\layout Itemize
+\begin_inset LatexCommand \htmlurl{http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/*checkout*/sdcc/sdcc/ChangeLog?rev=HEAD&content-type=text/plain}
--s <serial port file> passed to simulator see the simulator docs for details.
-\layout Itemize
+\end_inset
--S <serial in,out> passed to simulator see the simulator docs for details.
-\layout Subsection
+.
+\layout Section
-Debugger Commands.
-\layout Standard
+Release policy
+\begin_inset LatexCommand \index{Release policy}
+
+\end_inset
-As mention earlier the command interface for the debugger has been deliberately
- kept as close the GNU debugger gdb, as possible.
- This will help the integration with existing graphical user interfaces
- (like ddd, xxgdb or xemacs) existing for the GNU debugger.
-\layout Subsubsection
-break [line | file:line | function | file:function]
\layout Standard
-Set breakpoint at specified line or function:
-\newline
+Historically there often were long delays between official releases and
+ the sourceforge download area tends to get not updated at all.
+ Excuses in the past might have referred to problems with live range analysis,
+ but as this was fixed a while ago, the current problem is that another
+ excuse has to be found.
+ Kidding aside, we have to get better there! On the other hand there are
+ daily snapshots available at
+\begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
-\newline
+\end_inset
-\family sans
-\series bold
-sdcdb>break 100
-\newline
-sdcdb>break foo.c:100
-\newline
-sdcdb>break funcfoo
-\newline
-sdcdb>break foo.c:funcfoo
-\layout Subsubsection
+, and you can always build the very last version (hopefully with many bugs
+ fixed, and features added) from the source code available at
+\begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
-clear [line | file:line | function | file:function ]
-\layout Standard
+\end_inset
-Clear breakpoint at specified line or function:
-\newline
+.
+\layout Section
-\newline
+Examples
+\begin_inset LatexCommand \index{Examples}
+
+\end_inset
-\family sans
-\series bold
-sdcdb>clear 100
-\newline
-sdcdb>clear foo.c:100
-\newline
-sdcdb>clear funcfoo
-\newline
-sdcdb>clear foo.c:funcfoo
-\layout Subsubsection
-continue
\layout Standard
-Continue program being debugged, after breakpoint.
-\layout Subsubsection
+You'll find some small examples in the directory
+\emph on
+sdcc/device/examples/.
+
+\emph default
+More examples and libraries are available at
+\emph on
+ The SDCC Open Knowledge Resource
+\begin_inset LatexCommand \url{http://www.qsl.net/dl9sec/SDCC_OKR.html}
-finish
-\layout Standard
+\end_inset
-Execute till the end of the current function.
-\layout Subsubsection
+
+\emph default
+web site or at
+\begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}
-delete [n]
-\layout Standard
+\end_inset
-Delete breakpoint number 'n'.
- If used without any option clear ALL user defined break points.
-\layout Subsubsection
+.
+\layout Comment
-info [break | stack | frame | registers ]
-\layout Itemize
+I did insert a reference to Paul's web site here although it seems rather
+ dedicated to a specific 8032 board (I think it's okay because it f.e.
+ shows LCD/Harddisc interface and has a free 8051 monitor.
+ Independent 8032 board vendors face hard competition of heavily subsidized
+ development boards anyway).
+\layout Comment
-info break - list all breakpoints
-\layout Itemize
+Maybe we should include some links to real world applications.
+ Preferably pointer to pointers (one for each architecture) so this stays
+ manageable here?
+\layout Section
-info stack - show the function call stack.
-\layout Itemize
+Quality control
+\begin_inset LatexCommand \index{Quality control}
-info frame - show information about the current execution frame.
-\layout Itemize
+\end_inset
-info registers - show content of all registers.
-\layout Subsubsection
-step
\layout Standard
-Step program until it reaches a different source line.
-\layout Subsubsection
+The compiler is passed through nightly compile and build checks.
+ The so called
+\shape italic
+regression tests
+\shape default
-next
-\layout Standard
+\begin_inset LatexCommand \index{Regression test}
-Step program, proceeding through subroutine calls.
-\layout Subsubsection
+\end_inset
-run
-\layout Standard
+ check that SDCC itself compiles flawlessly on several platforms and checks
+ the quality of the code generated by SDCC by running the code through simulator
+s.
+ There is a separate document
+\shape italic
+test_suite.pdf
+\begin_inset LatexCommand \index{Test suite}
-Start debugged program.
-\layout Subsubsection
+\end_inset
-ptype variable
+
+\shape default
+ about this.
\layout Standard
-Print type information of the variable.
-\layout Subsubsection
+You'll find the test code in the directory
+\shape italic
+sdcc/support/regression
+\shape default
+.
+ You can run these tests manually by running
+\family sans
+make
+\family default
+ in this directory (or f.e.
+
+\family sans
+\series bold
-print variable
-\layout Standard
+\begin_inset Quotes sld
+\end_inset
-print value of variable.
-\layout Subsubsection
+make test-mcs51
+\begin_inset Quotes srd
+\end_inset
-file filename
-\layout Standard
-load the given file name.
- Note this is an alternate method of loading file for debugging.
-\layout Subsubsection
+\family default
+\series default
+ if you don't want to run the complete tests).
+ The test code might also be interesting if you want to look for examples
+\begin_inset LatexCommand \index{Examples}
-frame
-\layout Standard
+\end_inset
-print information about current frame.
-\layout Subsubsection
+ checking corner cases of SDCC or if you plan to submit patches
+\begin_inset LatexCommand \index{Patch submission}
-set srcmode
+\end_inset
+
+.
\layout Standard
-Toggle between C source & assembly source.
-\layout Subsubsection
+The pic port uses a different set of regression tests, you'll find them
+ in the directory
+\shape italic
+sdcc/src/regression
+\shape default
+.
+\layout Chapter
+\pagebreak_top
+SDCC Technical Data
+\layout Section
-! simulator command
-\layout Standard
+Optimizations
+\begin_inset LatexCommand \index{Optimizations}
+
+\end_inset
-Send the string following '!' to the simulator, the simulator response is
- displayed.
- Note the debugger does not interpret the command being sent to the simulator,
- so if a command like 'go' is sent the debugger can loose its execution
- context and may display incorrect values.
-\layout Subsubsection
-quit.
\layout Standard
-"Watch me now.
- Iam going Down.
- My name is Bobby Brown"
+SDCC performs a host of standard optimizations in addition to some MCU specific
+ optimizations.
+
\layout Subsection
-Interfacing with XEmacs
-\begin_inset LatexCommand \index{XEmacs}
+Sub-expression Elimination
+\begin_inset LatexCommand \index{Subexpression elimination}
\end_inset
-\begin_inset LatexCommand \index{Emacs}
-
-\end_inset
-
-.
\layout Standard
-Two files (in emacs lisp) are provided for the interfacing with XEmacs,
- sdcdb.el and sdcdbsrc.el.
- These two files can be found in the $(prefix)/bin directory after the installat
-ion is complete.
- These files need to be loaded into XEmacs for the interface to work.
- This can be done at XEmacs startup time by inserting the following into
- your '.xemacs' file (which can be found in your HOME directory):
-\newline
+The compiler does local and
+\emph on
+g
+\emph default
+lobal
+\emph on
+c
+\emph default
+ommon
+\emph on
+s
+\emph default
+ubexpression
+\emph on
+e
+\emph default
+limination, e.g.:
+\layout Verse
-\newline
\family typewriter
-(load-file sdcdbsrc.el)
-\family default
-
+i = x + y + 1;
\newline
+j = x + y;
+\layout Standard
+will be translated to
+\layout Verse
+
+
+\family typewriter
+iTemp = x + y;
\newline
-.xemacs is a lisp file so the () around the command is REQUIRED.
- The files can also be loaded dynamically while XEmacs is running, set the
- environment variable 'EMACSLOADPATH' to the installation bin directory
- (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
- To start the interface enter the following command:
+i = iTemp + 1;
\newline
+j = iTemp;
+\layout Standard
-\newline
+Some subexpressions are not as obvious as the above example, e.g.:
+\layout Verse
-\family sans
-\series bold
-ESC-x sdcdbsrc
-\family default
-\series default
+\family typewriter
+a->b[i].c = 10;
\newline
+a->b[i].d = 11;
+\layout Standard
+
+In this case the address arithmetic a->b[i] will be computed only once;
+ the equivalent code in C would be.
+\layout Verse
+
+\family typewriter
+iTemp = a->b[i];
\newline
-You will prompted to enter the file name to be debugged.
-
+iTemp.c = 10;
\newline
+iTemp.d = 11;
+\layout Standard
-\newline
-The command line options that are passed to the simulator directly are bound
- to default values in the file sdcdbsrc.el.
- The variables are listed below, these values maybe changed as required.
-\layout Itemize
+The compiler will try to keep these temporary variables in registers.
+\layout Subsection
-sdcdbsrc-cpu-type '51
-\layout Itemize
+Dead-Code Elimination
+\begin_inset LatexCommand \index{Dead-code elimination}
-sdcdbsrc-frequency '11059200
-\layout Itemize
+\end_inset
-sdcdbsrc-serial nil
-\layout Standard
-The following is a list of key mapping for the debugger interface.
-\layout Standard
+\layout Verse
-\SpecialChar ~
\family typewriter
-
-\newline
-;; Current Listing ::
-\newline
-;;key\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-binding\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-Comment
+int global;
\newline
-;;---\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-------\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
---------
+
\newline
-;;
+void f () {
\newline
-;; n\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdb-next-from-src\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-SDCDB next command
+int i;
\newline
-;; b\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdb-back-from-src\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+i = 1; \SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB back command
+/* dead store */
\newline
-;; c\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+global = 1;\SpecialChar ~
+/* dead store */
+\newline
\SpecialChar ~
\SpecialChar ~
+global = 2;
+\newline
\SpecialChar ~
\SpecialChar ~
+return;
+\newline
\SpecialChar ~
\SpecialChar ~
+global = 3;\SpecialChar ~
+/* unreachable */
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int global;
+\newline
+
+\newline
+void f () {
+\newline
\SpecialChar ~
- sdcdb-cont-from-src\SpecialChar ~
\SpecialChar ~
+global = 2;
+\newline
\SpecialChar ~
\SpecialChar ~
+return;
+\newline
+}
+\layout Subsection
+
+Copy-Propagation
+\begin_inset LatexCommand \index{Copy propagation}
+
+\end_inset
+
+
+\layout Verse
+
+
+\family typewriter
+int f() {
+\newline
\SpecialChar ~
\SpecialChar ~
+int i, j;
+\newline
\SpecialChar ~
\SpecialChar ~
+i = 10;
+\newline
\SpecialChar ~
\SpecialChar ~
-SDCDB continue command
+j = i;
\newline
-;; s\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+return j;
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int f() {
+\newline
\SpecialChar ~
\SpecialChar ~
+int i, j;
+\newline
\SpecialChar ~
\SpecialChar ~
+i = 10;
+\newline
\SpecialChar ~
\SpecialChar ~
+j = 10;
+\newline
\SpecialChar ~
\SpecialChar ~
+return 10;
+\newline
+}
+\layout Standard
+
+Note: the dead stores created by this copy propagation will be eliminated
+ by dead-code elimination.
+\layout Subsection
+
+Loop Optimizations
+\begin_inset LatexCommand \index{Loop optimization}
+
+\end_inset
+
+
+\layout Standard
+
+Two types of loop optimizations are done by SDCC loop invariant lifting
+ and strength reduction of loop induction variables.
+ In addition to the strength reduction the optimizer marks the induction
+ variables and the register allocator tries to keep the induction variables
+ in registers for the duration of the loop.
+ Because of this preference of the register allocator
+\begin_inset LatexCommand \index{Register allocation}
+
+\end_inset
+
+, loop induction optimization causes an increase in register pressure, which
+ may cause unwanted spilling of other temporary variables into the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ / data space.
+ The compiler will generate a warning message when it is forced to allocate
+ extra space either on the stack or data space.
+ If this extra space allocation is undesirable then induction optimization
+ can be eliminated either for the entire source file (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noinduction option) or for a given function only using #pragma\SpecialChar ~
+noinduction
+\begin_inset LatexCommand \index{\#pragma noinduction}
+
+\end_inset
+
+.
+\newline
+
+\newline
+Loop Invariant:
+\layout Verse
+
+
+\family typewriter
+for (i = 0 ; i < 100 ; i ++)
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdb-step-from-src\SpecialChar ~
\SpecialChar ~
+f += k + l;
+\layout Standard
+
+changed to
+\layout Verse
+
+
+\family typewriter
+itemp = k + l;
+\newline
+for (i = 0; i < 100; i++)
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+f += itemp;
+\layout Standard
+
+As mentioned previously some loop invariants are not as apparent, all static
+ address computations are also moved out of the loop.
+\newline
+
+\newline
+Strength Reduction
+\begin_inset LatexCommand \index{Strength reduction}
+
+\end_inset
+
+, this optimization substitutes an expression by a cheaper expression:
+\layout Verse
+
+
+\family typewriter
+for (i=0;i < 100; i++)
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB step command
+ar[i*5] = i*3;
+\layout Standard
+
+changed to
+\layout Verse
+
+
+\family typewriter
+itemp1 = 0;
+\newline
+itemp2 = 0;
+\newline
+for (i=0;i< 100;i++) {
\newline
-;; ?\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ar[itemp1] = itemp2;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+itemp1 += 5;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+itemp2 += 3;
+\newline
+}
+\layout Standard
+
+The more expensive multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ is changed to a less expensive addition.
+\layout Subsection
+
+Loop Reversing
+\begin_inset LatexCommand \index{Loop reversing}
+
+\end_inset
+
+
+\layout Standard
+
+This optimization is done to reduce the overhead of checking loop boundaries
+ for every iteration.
+ Some simple loops can be reversed and implemented using a
+\begin_inset Quotes eld
+\end_inset
+
+decrement and jump if not zero
+\begin_inset Quotes erd
+\end_inset
+
+ instruction.
+ SDCC checks for the following criterion to determine if a loop is reversible
+ (note: more sophisticated compilers use data-dependency analysis to make
+ this determination, SDCC uses a more simple minded analysis).
+\layout Itemize
+
+The 'for' loop is of the form
+\newline
+
+\newline
+
+\family typewriter
+for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
+ += 1])
+\newline
\SpecialChar ~
- sdcdb-whatis-c-sexp\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+<for body>
+\layout Itemize
+
+The <for body> does not contain
+\begin_inset Quotes eld
+\end_inset
+
+continue
+\begin_inset Quotes erd
+\end_inset
+
+ or 'break
+\begin_inset Quotes erd
+\end_inset
+
+.
+\layout Itemize
+
+All goto's are contained within the loop.
+\layout Itemize
+
+No function calls within the loop.
+\layout Itemize
+
+The loop control variable <sym> is not assigned any value within the loop
+\layout Itemize
+
+The loop control variable does NOT participate in any arithmetic operation
+ within the loop.
+\layout Itemize
+
+There are NO switch statements in the loop.
+\layout Subsection
+
+Algebraic Simplifications
+\layout Standard
+
+SDCC does numerous algebraic simplifications, the following is a small sub-set
+ of these optimizations.
+\layout Verse
+
+
+\family typewriter
+i = j + 0;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ /* changed to: */\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB ptypecommand for data at
+ i = j;
\newline
-;;\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+i /= 2;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ /* changed to: */\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ i >>= 1;
+\newline
+i = j - j;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ /* changed to: */\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- buffer point
+ i = 0;
\newline
-;; x\SpecialChar ~
-\SpecialChar ~
+i = j / 1;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ /* changed to: */\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ i = j;
+\layout Standard
+
+Note the subexpressions
+\begin_inset LatexCommand \index{Subexpression}
+
+\end_inset
+
+ given above are generally introduced by macro expansions or as a result
+ of copy/constant propagation.
+\layout Subsection
+
+'switch' Statements
+\begin_inset LatexCommand \label{sub:'switch'-Statements}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{switch statement}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC changes switch statements to jump tables
+\begin_inset LatexCommand \index{jump tables}
+
+\end_inset
+
+ when the following conditions are true.
+
+\layout Itemize
+
+The case labels are in numerical sequence, the labels need not be in order,
+ and the starting number need not be one or zero.
+\begin_deeper
+\layout Verse
+
+
+\family typewriter
+switch(i) {\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdbsrc-delete\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB Delete all breakpoints if no arg
-\newline
-;;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+switch (i) {
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 4: ...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 0: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 5: ...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-given or delete arg (C-u arg x)
-\newline
-;; m\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdbsrc-frame\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 1: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 3: ...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB Display current frame if no arg,
-\newline
-;;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 2: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 6: ...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-given or display frame arg
+case 3: ...
+
\newline
-;;\SpecialChar ~
-\SpecialChar ~
+}\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+}
+\layout Standard
+
+Both the above switch statements will be implemented using a jump-table.
+ The example to the right side is slightly more efficient as the check for
+ the lower boundary of the jump-table is not needed.
+\end_deeper
+\layout Itemize
+
+The number of case labels is at least three, since it takes two conditional
+ statements to handle the boundary conditions.
+\layout Itemize
+
+The number of case labels is less than 84, since each label takes 3 bytes
+ and a jump-table can be utmost 256 bytes long.
+\layout Standard
+
+Switch statements which have gaps in the numeric sequence or those that
+ have more that 84 case labels can be split into more than one switch statement
+ for efficient code generation, e.g.:
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
\SpecialChar ~
\SpecialChar ~
+case 1: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 2: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 3: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 4: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
-buffer point
+case 9: ...
+
\newline
-;; !\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 10: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 11: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 12: ...
+
+\newline
+}
+\layout Standard
+
+If the above switch statement is broken down into two switch statements
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
\SpecialChar ~
\SpecialChar ~
+case 1: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 2: ...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 3: ...
+
+\newline
\SpecialChar ~
- sdcdbsrc-goto-sdcdb\SpecialChar ~
\SpecialChar ~
+case 4: ...
+
+\newline
+}
+\layout Standard
+
+and
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
\SpecialChar ~
\SpecialChar ~
+case 9:\SpecialChar ~
\SpecialChar ~
+...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 10:\SpecialChar ~
+...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+case 11:\SpecialChar ~
+...
+
+\newline
\SpecialChar ~
-Goto the SDCDB output buffer
+\SpecialChar ~
+case 12:\SpecialChar ~
+...
+
+\newline
+}
+\layout Standard
+
+then both the switch statements will be implemented using jump-tables whereas
+ the unmodified switch statement will not be.
+ You might also consider inserting dummy cases 0 and 5 to 8 in this example.
+
+\newline
+The pragma nojtbound
+\begin_inset LatexCommand \index{\#pragma nojtbound}
+
+\end_inset
+
+ can be used to turn off checking the
+\emph on
+j
+\emph default
+ump
+\emph on
+t
+\emph default
+able
+\emph on
+bound
+\emph default
+aries.
+ It has no effect if a default label is supplied.
+ Use of this pragma is dangerous: if the switch argument is not matched
+ by a case statement the processor will happily jump into Nirvana.
+\layout Subsection
+
+Bit-shifting Operations
+\begin_inset LatexCommand \index{Bit shifting}
+
+\end_inset
+
+.
+\layout Standard
+
+Bit shifting is one of the most frequently used operation in embedded programmin
+g.
+ SDCC tries to implement bit-shift operations in the most efficient way
+ possible, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned char i;
+\newline
+...
+
+\newline
+i >>= 4;
+\newline
+...
+\layout Standard
+
+generates the following code:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
+ a,_i
+\newline
+swap a
+\newline
+anl\SpecialChar ~
+ a,#0x0f
+\newline
+mov\SpecialChar ~
+ _i,a
+\layout Standard
+
+In general SDCC will never setup a loop if the shift count is known.
+ Another example:
+\layout Verse
+
+
+\family typewriter
+unsigned int i;
\newline
-;; p\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+...
+
+\newline
+i >>= 9;
+\newline
+...
+\layout Standard
+
+will generate:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
\SpecialChar ~
+a,(_i + 1)
+\newline
+mov\SpecialChar ~
\SpecialChar ~
+(_i + 1),#0x00
+\newline
+clr\SpecialChar ~
\SpecialChar ~
+c
+\newline
+rrc\SpecialChar ~
\SpecialChar ~
+a
+\newline
+mov\SpecialChar ~
\SpecialChar ~
+_i,a
+\layout Subsection
+
+Bit-rotation
+\begin_inset LatexCommand \index{Bit rotation}
+
+\end_inset
+
+
+\layout Standard
+
+A special case of the bit-shift operation is bit rotation
+\begin_inset LatexCommand \index{rotating bits}
+
+\end_inset
+
+, SDCC recognizes the following expression to be a left bit-rotation:
+\layout Verse
+
+
+\family typewriter
+\series bold
+unsigned
+\series default
\SpecialChar ~
\SpecialChar ~
- sdcdb-print-c-sexp\SpecialChar ~
+char i;\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB print command for data at
+/* unsigned is needed for rotation */
\newline
-;;\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+...
+
+\newline
+i = ((i << 1) | (i >> 7));
+\family default
+
+\newline
+
+\family typewriter
+...
+\layout Standard
+
+will generate the following code:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
\SpecialChar ~
+a,_i
+\newline
+rl\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+a
+\newline
+mov\SpecialChar ~
\SpecialChar ~
+_i,a
+\layout Standard
+
+SDCC uses pattern matching on the parse tree to determine this operation.Variatio
+ns of this case will also be recognized as bit-rotation, i.e.:
+\layout Verse
+
+
+\family typewriter
+i = ((i >> 7) | (i << 1)); /* left-bit rotation */
+\layout Subsection
+
+Nibble and Byte Swapping
+\layout Standard
+
+Other special cases of the bit-shift operations are nibble or byte swapping
+\begin_inset LatexCommand \index{swapping nibbles/bytes}
+
+\end_inset
+
+, SDCC recognizes the following expressions:
+\layout Verse
+
+
+\family typewriter
+\series bold
+unsigned
+\series default
\SpecialChar ~
\SpecialChar ~
+char i;
+\newline
+
+\series bold
+unsigned
+\series default
\SpecialChar ~
\SpecialChar ~
+int j;
+\newline
+...
+
+\newline
+i = ((i << 4) | (i >> 4));
+\family default
+
+\newline
+
+\family typewriter
+j = ((j << 8) | (j >> 8));
+\layout Standard
+
+and generates a swap instruction for the nibble swapping
+\begin_inset LatexCommand \index{Nibble swapping}
+
+\end_inset
+
+ or move instructions for the byte swapping
+\begin_inset LatexCommand \index{Byte swapping}
+
+\end_inset
+
+.
+ The
+\begin_inset Quotes sld
+\end_inset
+
+j
+\begin_inset Quotes srd
+\end_inset
+
+ example can be used to convert from little to big-endian or vice versa.
+ If you want to change the endianness of a
+\emph on
+signed
+\emph default
+ integer you have to cast to
+\family typewriter
+(unsigned int)
+\family default
+ first.
+\layout Standard
+
+Note that SDCC stores numbers in little-endian
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+Usually 8-bit processors don't care much about endianness.
+ This is not the case for the standard 8051 which only has an instruction
+ to increment its
+\emph on
+dptr
+\emph default
+
+\begin_inset LatexCommand \index{DPTR}
+
+\end_inset
+
+-datapointer
+\emph on
+
+\emph default
+so little-endian is the more efficient byte order.
+\end_inset
+
+
+\begin_inset LatexCommand \index{little-endian}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Endianness}
+
+\end_inset
+
+ format (i.e.
+ lowest order first).
+\layout Subsection
+
+Highest Order Bit
+\begin_inset LatexCommand \index{Highest Order Bit}
+
+\end_inset
+
+
+\layout Standard
+
+It is frequently required to obtain the highest order bit of an integral
+ type (long, int, short or char types).
+ SDCC recognizes the following expression to yield the highest order bit
+ and generates optimized code for it, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned int gint;
+\newline
+
+\newline
+foo () {
+\newline
\SpecialChar ~
\SpecialChar ~
+unsigned char hob;
+\newline
\SpecialChar ~
\SpecialChar ~
+...
+
+\newline
\SpecialChar ~
\SpecialChar ~
+hob = (gint >> 15) & 1;
+\newline
\SpecialChar ~
\SpecialChar ~
+..
+
+\newline
+}
+\layout Standard
+
+will generate the following code:
+\layout Verse
+
+
+\family typewriter
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- buffer point
+ 61 ;\SpecialChar ~
+ hob.c 7
\newline
-;; g\SpecialChar ~
+000A E5*01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdbsrc-goto-sdcdb\SpecialChar ~
\SpecialChar ~
+ 62\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ mov\SpecialChar ~
\SpecialChar ~
-Goto the SDCDB output buffer
+ a,(_gint + 1)
\newline
-;; t\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+000C 23\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
- sdcdbsrc-mode\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-Toggles Sdcdbsrc mode (turns it off)
-\newline
-;;
-\newline
-;; C-c C-f\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+ 63\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdb-finish-from-src\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ rl\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-SDCDB finish command
-\newline
-;;
+ a
\newline
-;; C-x SPC\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdb-break\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+000D 54 01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-Set break for line with point
-\newline
-;; ESC t\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ 64\SpecialChar ~
\SpecialChar ~
- sdcdbsrc-mode\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ anl\SpecialChar ~
\SpecialChar ~
+ a,#0x01
+\newline
+000F F5*02\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-Toggle Sdcdbsrc mode
-\newline
-;; ESC m\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ 65\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- sdcdbsrc-srcmode\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ mov\SpecialChar ~
\SpecialChar ~
+ _foo_hob_1_1,a
+\layout Standard
+
+Variations of this case however will
+\emph on
+not
+\emph default
+ be recognized.
+ It is a standard C expression, so I heartily recommend this be the only
+ way to get the highest order bit, (it is portable).
+ Of course it will be recognized even if it is embedded in other expressions,
+ e.g.:
+\layout Verse
+
+
+\family typewriter
+xyz = gint + ((gint >> 15) & 1);
+\layout Standard
+
+will still be recognized.
+\layout Subsection
+
+Peephole Optimizer
+\begin_inset LatexCommand \label{sub:Peephole-Optimizer}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Peephole optimizer}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler uses a rule based, pattern matching and re-writing mechanism
+ for peep-hole optimization.
+ It is inspired by
+\emph on
+copt
+\emph default
+ a peep-hole optimizer by Christopher W.
+ Fraser (cwfraser@microsoft.com).
+ A default set of rules are compiled into the compiler, additional rules
+ may be added with the
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file
+\begin_inset LatexCommand \index{-\/-peep-file}
+
+\end_inset
+
+ <filename>
+\emph default
+ option.
+ The rule language is best illustrated with examples.
+\layout Verse
+
+
+\family typewriter
+replace {
+\newline
\SpecialChar ~
\SpecialChar ~
+mov %1,a
+\newline
\SpecialChar ~
\SpecialChar ~
+mov a,%1
+\newline
+} by {
+\newline
\SpecialChar ~
\SpecialChar ~
- Toggle list mode
+mov %1,a
\newline
-;;
-\family default
+}
+\layout Standard
+
+The above rule will change the following assembly
+\begin_inset LatexCommand \index{Assembler routines}
+
+\end_inset
+
+ sequence:
+\layout Verse
+
+\family typewriter
+mov r1,a
\newline
+mov a,r1
+\layout Standard
-\layout Section
+to
+\layout Verse
-Other Processors
-\layout Subsection
-The Z80 and gbz80 port
+\family typewriter
+mov r1,a
\layout Standard
-SDCC can target both the Zilog Z80 and the Nintendo Gameboy's Z80-like gbz80.
- The port is incomplete - long support is incomplete (mul, div and mod are
- unimplimented), and both float and bitfield support is missing.
- Apart from that the code generated is correct.
+Note: All occurrences of a
+\emph on
+%n
+\emph default
+ (pattern variable) must denote the same string.
+ With the above rule, the assembly sequence:
+\layout Verse
+
+
+\family typewriter
+mov r1,a
+\newline
+mov a,r2
\layout Standard
-As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c.
- The stack frame is similar to that generated by the IAR Z80 compiler.
- IX is used as the base pointer, HL is used as a temporary register, and
- BC and DE are available for holding varibles.
- IY is currently unusued.
- Return values are stored in HL.
- One bad side effect of using IX as the base pointer is that a functions
- stack frame is limited to 127 bytes - this will be fixed in a later version.
-\layout Section
-\pagebreak_top
-Support
-\begin_inset LatexCommand \index{Support}
+will remain unmodified.
+\newline
+
+\newline
+Other special case optimizations may be added by the user (via
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+\backslash
+/
\end_inset
+-peep-file option
+\emph default
+).
+ E.g.
+ some variants of the 8051 MCU allow only
+\family typewriter
+ajmp
+\family default
+ and
+\family typewriter
+acall
+\family default
+.
+ The following two rules will change all
+\family typewriter
+ljmp
+\family default
+ and
+\family typewriter
+lcall
+\family default
+ to
+\family typewriter
+ajmp
+\family default
+ and
+\family typewriter
+acall
+\layout Verse
+
+\family typewriter
+replace { lcall %1 } by { acall %1 }
+\newline
+replace { ljmp %1 } by { ajmp %1 }
\layout Standard
-SDCC has grown to be a large project.
- The compiler alone (without the preprocessor, assembler and linker) is
- about 40,000 lines of code (blank stripped).
- The open source nature of this project is a key to its continued growth
- and support.
- You gain the benefit and support of many active software developers and
- end users.
- Is SDCC perfect? No, that's why we need your help.
- The developers take pride in fixing reported bugs.
- You can help by reporting the bugs and helping other SDCC users.
- There are lots of ways to contribute, and we encourage you to take part
- in making SDCC a great software package.
-
+The
+\emph on
+inline-assembler code
+\emph default
+ is also passed through the peep hole optimizer, thus the peephole optimizer
+ can also be used as an assembly level macro expander.
+ The rules themselves are MCU dependent whereas the rule language infra-structur
+e is MCU independent.
+ Peephole optimization rules for other MCU can be easily programmed using
+ the rule language.
+\newline
+
+\newline
+The syntax for a rule is as follows:
+\layout Verse
+
+
+\family typewriter
+rule := replace [ restart ] '{' <assembly sequence> '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ '}' by '{' '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ <assembly sequence> '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ '}' [if <functionName> ] '
+\backslash
+n'
\layout Standard
-The SDCC project is hosted on the sdcc sourceforge site at
-\begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
-
-\end_inset
+<assembly sequence> := assembly instruction (each instruction including
+ labels must be on a separate line).
+\newline
-.
- You'll find the complete set of mailing lists
-\begin_inset LatexCommand \index{Mailing list}
+\newline
+The optimizer will apply to the rules one by one from the top in the sequence
+ of their appearance, it will terminate when all rules are exhausted.
+ If the 'restart' option is specified, then the optimizer will start matching
+ the rules again from the top, this option for a rule is expensive (performance)
+, it is intended to be used in situations where a transformation will trigger
+ the same rule again.
+ An example of this (not a good one, it has side effects) is the following
+ rule:
+\layout Verse
-\end_inset
-, forums, bug reporting system, patch submission
-\begin_inset LatexCommand \index{Patch submission}
+\family typewriter
+replace restart {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+pop %1
+\newline
+\SpecialChar ~
+\SpecialChar ~
+push %1 } by {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+; nop
+\newline
+}
+\layout Standard
-\end_inset
+Note that the replace pattern cannot be a blank, but can be a comment line.
+ Without the 'restart' option only the innermost 'pop' 'push' pair would
+ be eliminated, i.e.:
+\layout Verse
- system, download
-\begin_inset LatexCommand \index{download}
-\end_inset
+\family typewriter
+pop ar1
+\newline
+pop ar2
+\newline
+push ar2
+\newline
+push ar1
+\layout Standard
- area and cvs code repository
-\begin_inset LatexCommand \index{cvs code repository}
+would result in:
+\layout Verse
-\end_inset
- there.
-\layout Subsection
+\family typewriter
+pop ar1
+\newline
+; nop
+\newline
+push ar1
+\layout Standard
-Reporting Bugs
-\begin_inset LatexCommand \index{Bugs}
-\end_inset
+\emph on
+with
+\emph default
+ the restart option the rule will be applied again to the resulting code
+ and then all the pop-push pairs will be eliminated to yield:
+\layout Verse
-\begin_inset LatexCommand \index{Reporting bugs}
+\family typewriter
+; nop
+\newline
+; nop
+\layout Standard
-\end_inset
+A conditional function can be attached to a rule.
+ Attaching rules are somewhat more involved, let me illustrate this with
+ an example.
+\layout Verse
+\family typewriter
+replace {
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ljmp %5
+\newline
+%2:
+\newline
+} by {
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+sjmp %5
+\newline
+%2:
+\newline
+} if labelInRange
\layout Standard
-The recommended way of reporting bugs is using the infrastructure of the
- sourceforge site.
- You can follow the status of bug reports there and have an overview about
- the known bugs.
+The optimizer does a look-up of a function name table defined in function
+
+\emph on
+callFuncByName
+\emph default
+ in the source file SDCCpeeph.c, with the name
+\emph on
+labelInRange
+\emph default
+.
+ If it finds a corresponding entry the function is called.
+ Note there can be no parameters specified for these functions, in this
+ case the use of
+\emph on
+%5
+\emph default
+ is crucial, since the function
+\emph on
+labelInRange
+\emph default
+ expects to find the label in that particular variable (the hash table containin
+g the variable bindings is passed as a parameter).
+ If you want to code more such functions, take a close look at the function
+ labelInRange and the calling mechanism in source file SDCCpeeph.c.
+ Currently implemented are
+\emph on
+labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
+ 24bitMode, portIsDS390, 24bitModeAndPortDS390
+\emph default
+and
+\emph on
+ notVolatile
+\emph default
+.
\layout Standard
-Bug reports are automatically forwarded to the developer mailing list and
- will be fixed ASAP.
- When reporting a bug, it is very useful to include a small test program
- which reproduces the problem.
- If you can isolate the problem by looking at the generated assembly code,
- this can be very helpful.
- Compiling your program with the -
+I know this whole thing is a little kludgey, but maybe some day we will
+ have some better means.
+ If you are looking at this file, you will see the default rules that are
+ compiled into the compiler, you can add your own rules in the default set
+ there if you get tired of specifying the -
\begin_inset ERT
status Collapsed
/
\end_inset
--dumpall
-\begin_inset LatexCommand \index{-\/-dumpall}
+-peep-file option.
+\layout Section
+
+ANSI-Compliance
+\begin_inset LatexCommand \index{ANSI-compliance}
\end_inset
- option can sometimes be useful in locating optimization problems.
-\layout Standard
-Please have a short check that you are using a recent version of SDCC and
- the bug is not yet known.
- This is the link for reporting bugs:
-\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
+\begin_inset LatexCommand \label{sub:ANSI-Compliance}
\end_inset
-.
-\layout Subsection
-
-Requesting Features
-\begin_inset LatexCommand \index{Feature request}
-\end_inset
+\layout Standard
+Deviations from the compliance:
+\layout Itemize
-\begin_inset LatexCommand \index{Requesting features}
+functions are not always reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
+.
+\layout Itemize
-\layout Standard
+structures cannot be assigned values directly, cannot be passed as function
+ parameters or assigned to each other and cannot be a return value from
+ a function, e.g.:
+\begin_deeper
+\layout Verse
-Like bug reports feature requests are forwarded to the developer mailing
- list.
- This is the link for requesting features:
-\begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
+
+\family typewriter
+struct s { ...
+ };
+\newline
+struct s s1, s2;
+\newline
+foo()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\newline
+struct s foo1 (struct s parms) /* invalid in SDCC although allowed in ANSI
+ */
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+struct s rets;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return rets;/* is invalid in SDCC although allowed in ANSI */
+\newline
+}
+\end_deeper
+\layout Itemize
+
+'long long
+\begin_inset LatexCommand \index{long long (not supported)}
\end_inset
-.
-\layout Subsection
+' (64 bit integers
+\begin_inset LatexCommand \index{int (64 bit) (not supported)}
-Getting Help
-\layout Standard
+\end_inset
-These links should take you directly to the
-\begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
+) not supported.
+\layout Itemize
+
+'double
+\begin_inset LatexCommand \index{double (not supported)}
\end_inset
+' precision floating point
+\begin_inset LatexCommand \index{Floating point support}
-\begin_inset Foot
-collapsed false
+\end_inset
-\layout Standard
+not supported.
+\layout Itemize
+
+No support for setjmp
+\begin_inset LatexCommand \index{setjmp (not supported)}
-Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
- automated messages (mid 2003)
\end_inset
- and the
-\begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
+ and longjmp
+\begin_inset LatexCommand \index{longjmp (not supported)}
\end_inset
-, lists and forums are archived so if you are lucky someone already had
- a similar problem.
-\layout Subsection
+ (for now).
+\layout Itemize
-Changelog
-\begin_inset LatexCommand \index{Changelog}
+Old K&R style
+\begin_inset LatexCommand \index{K\&R style}
\end_inset
+ function declarations are NOT allowed.
+\begin_deeper
+\layout Verse
-\layout Standard
-
-You can follow the status of the cvs version
-\begin_inset LatexCommand \index{version}
-\end_inset
+\family typewriter
+foo(i,j) /* this old style of function declarations */
+\newline
+int i,j; /* are valid in ANSI but not valid in SDCC */
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\end_deeper
+\layout Itemize
- of SDCC by watching the file
-\begin_inset LatexCommand \htmlurl[ChangeLog]{http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/*checkout*/sdcc/sdcc/ChangeLog?rev=HEAD&content-type=text/plain}
+functions declared as pointers
+\begin_inset LatexCommand \index{Pointer (to function)}
\end_inset
- in the cvs-repository.
-\layout Subsection
-Release policy
-\begin_inset LatexCommand \index{Release policy}
+\begin_inset LatexCommand \index{function pointers}
\end_inset
+ must be dereferenced during the call.
+\begin_deeper
+\layout Verse
-\layout Standard
-Historically there often were long delays between official releases and
- the sourceforge download area tends to get not updated at all.
- Current excuses might refer to problems with live range analysis, but if
- this is fixed, the next problem rising is that another excuse will have
- to be found.
- Kidding aside, we have to get better there!
-\layout Subsection
+\family typewriter
+int (*foo)();
+\newline
+...
+
+\newline
+/* has to be called like this */
+\newline
+(*foo)(); /* ANSI standard allows calls to be made like 'foo()' */
+\end_deeper
+\layout Section
-Examples
-\begin_inset LatexCommand \index{Examples}
+Cyclomatic Complexity
+\begin_inset LatexCommand \index{Cyclomatic complexity}
\end_inset
\layout Standard
-You'll find some small examples in the directory sdcc/device/examples/
-\layout Comment
+Cyclomatic complexity of a function is defined as the number of independent
+ paths the program can take during execution of the function.
+ This is an important number since it defines the number test cases you
+ have to generate to validate the function.
+ The accepted industry standard for complexity number is 10, if the cyclomatic
+ complexity reported by SDCC exceeds 10 you should think about simplification
+ of the function logic.
+ Note that the complexity level is not related to the number of lines of
+ code in a function.
+ Large functions can have low complexity, and small functions can have large
+ complexity levels.
+
+\newline
-Maybe we should include some links to real world applications.
- Preferrably pointer to pointers (one for each architecture) so this stays
- manageable here?
-\layout Subsection
+\newline
+SDCC uses the following formula to compute the complexity:
+\newline
-Quality control
-\begin_inset LatexCommand \index{Quality control}
+\layout Standard
-\end_inset
+complexity = (number of edges in control flow graph) - (number of nodes
+ in control flow graph) + 2;
+\newline
+\newline
+Having said that the industry standard is 10, you should be aware that in
+ some cases it be may unavoidable to have a complexity level of less than
+ 10.
+ For example if you have switch statement with more than 10 case labels,
+ each case label adds one to the complexity level.
+ The complexity level is by no means an absolute measure of the algorithmic
+ complexity of the function, it does however provide a good starting point
+ for which functions you might look at for further optimization.
+\layout Section
+Retargetting for other Processors
\layout Standard
-The compiler is passed through nightly compile and build checks.
- The so called
-\shape italic
-regression tests
-\shape default
+The issues for retargetting the compiler are far too numerous to be covered
+ by this document.
+ What follows is a brief description of each of the seven phases of the
+ compiler and its MCU dependency.
+\layout Itemize
-\begin_inset LatexCommand \index{Regression test}
+Parsing the source and building the annotated parse tree.
+ This phase is largely MCU independent (except for the language extensions).
+ Syntax & semantic checks are also done in this phase, along with some initial
+ optimizations like back patching labels and the pattern matching optimizations
+ like bit-rotation etc.
+\layout Itemize
-\end_inset
+The second phase involves generating an intermediate code which can be easy
+ manipulated during the later phases.
+ This phase is entirely MCU independent.
+ The intermediate code generation assumes the target machine has unlimited
+ number of registers, and designates them with the name iTemp.
+ The compiler can be made to dump a human readable form of the code generated
+ by using the -
+\begin_inset ERT
+status Collapsed
- check that SDCC itself compiles flawlessly on several platforms and checks
- the quality of the code generated by SDCC by running the code through simulator
-s.
- There is a separate document
-\shape italic
-test_suite.pdf
-\begin_inset LatexCommand \index{Test suite}
+\layout Standard
+\backslash
+/
\end_inset
+-dumpraw option.
+\layout Itemize
-\shape default
- about this.
-\layout Standard
+This phase does the bulk of the standard optimizations and is also MCU independe
+nt.
+ This phase can be broken down into several sub-phases:
+\newline
-You'll find the test code in the directory
-\shape italic
-sdcc/support/regression
-\shape default
-.
- You can run these tests manually by running
-\family sans
-make
-\family default
- in this directory (or f.e.
-
-\family sans
-make test-mcs51
-\family default
- if you don't want to run the complete tests).
- The test code might also be interesting if you want to look for examples
-\begin_inset LatexCommand \index{Examples}
+\newline
+Break down intermediate code (iCode) into basic blocks.
+\newline
+Do control flow & data flow analysis on the basic blocks.
+\newline
+Do local common subexpression elimination, then global subexpression elimination
+\newline
+Dead code elimination
+\newline
+Loop optimizations
+\newline
+If loop optimizations caused any changes then do 'global subexpression eliminati
+on' and 'dead code elimination' again.
+\layout Itemize
+
+This phase determines the live-ranges; by live range I mean those iTemp
+ variables defined by the compiler that still survive after all the optimization
+s.
+ Live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
- checking corner cases of SDCC or if you plan to submit patches
-\begin_inset LatexCommand \index{Patch submission}
+ is essential for register allocation, since these computation determines
+ which of these iTemps will be assigned to registers, and for how long.
+\layout Itemize
-\end_inset
+Phase five is register allocation.
+ There are two parts to this process.
+\newline
-.
-\layout Standard
+\newline
+The first part I call 'register packing' (for lack of a better term).
+ In this case several MCU specific expression folding is done to reduce
+ register pressure.
+\newline
+
+\newline
+The second part is more MCU independent and deals with allocating registers
+ to the remaining live ranges.
+ A lot of MCU specific code does creep into this phase because of the limited
+ number of index registers available in the 8051.
+\layout Itemize
+
+The Code generation phase is (unhappily), entirely MCU dependent and very
+ little (if any at all) of this code can be reused for other MCU.
+ However the scheme for allocating a homogenized assembler operand for each
+ iCode operand may be reused.
+\layout Itemize
+
+As mentioned in the optimization section the peep-hole optimizer is rule
+ based system, which can reprogrammed for other MCUs.
+\layout Chapter
-The pic port uses a different set of regression tests, you'll find them
- in the directory
-\shape italic
-sdcc/src/regression
-\shape default
-.
-\layout Section
-\pagebreak_top
Compiler internals
\begin_inset LatexCommand \index{Compiler internals}
\end_inset
-\layout Subsection
+\layout Section
The anatomy of the compiler
+\begin_inset LatexCommand \label{sub:The-anatomy-of}
+
+\end_inset
+
+
\layout Standard
\shape italic
-This is an excerpt from an atricle published in Circuit Cellar MagaZine
+This is an excerpt from an article published in Circuit Cellar Magazine
in august 2000.
It's a little outdated (the compiler is much more efficient now and user/develo
per friendly), but pretty well exposes the guts of it all.
There are other MCU specific considerations in this phase.
Some MCUs have an accumulator; very short-lived operands could be assigned
- to the accumulator instead of general-purpose register.
+ to the accumulator instead of a general-purpose register.
\layout Paragraph*
Code generation
This section shows some details of iCode.
The example C code does not do anything useful; it is used as an example
to illustrate the intermediate code generated by the compiler.
-\newline
+\layout Verse
-\newline
\family typewriter
1.\SpecialChar ~
7.\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-short i=10; /* dead initialization eliminated */
+short i=10; \SpecialChar ~
+\SpecialChar ~
+/* dead initialization eliminated */
\newline
8.\SpecialChar ~
\SpecialChar ~
\newline
15.\SpecialChar ~
\SpecialChar ~
-for (i = 0, j = 10 ; i < 10 ; i++, j--) {
+for (i = 0, j = 10 ; i < 10 ; i++, j
+\family default
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-
+\family typewriter
+) {
\newline
16.\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mul += i * 3; /* this multiplication remains */
+mul += i * 3; \SpecialChar ~
+\SpecialChar ~
+/* this multiplication remains */
\newline
18.\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-gint += j * 3;/* this multiplication changed to addition */
+gint += j * 3;\SpecialChar ~
+\SpecialChar ~
+/* this multiplication changed to addition */
\newline
19.\SpecialChar ~
\SpecialChar ~
\newline
21.\SpecialChar ~
}
-\newline
-
-\newline
+\layout Standard
-\family default
In addition to the operands each iCode contains information about the filename
and line it corresponds to in the source file.
The first field in the listing should be interpreted as follows:
In addition the allocator also takes into consideration the type and usage
of a temporary, for example itemp6 is a pointer to near space and is used
as to fetch data from (i.e.
- used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer registers (r0).
+ used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
Some short lived temporaries are allocated to special registers which have
meaning to the code generator e.g.
iTemp13 is allocated to a pseudo register CC which tells the back end that
ret
\newline
-\layout Subsection
+\layout Section
A few words about basic block successors, predecessors and dominators
\layout Standard
if (something)
\layout Standard
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
[basic block 2]
\layout Standard
else
\layout Standard
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
[basic block 3]
\layout Standard
c) domVect of [BB4] = BB1 ...
here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
was executed.
-\layout Section
+\layout Chapter
Acknowledgments
\layout Standard
of their respective companies.
-\layout Section
+\layout Section*
Alphabetical index
\layout Standard
-To avoid confusion, the installation and building options for sdcc itself
+To avoid confusion, the installation and building options for SDCC itself
(chapter 2) are not part of the index.
\layout Standard
projects / fw / sdcc / blobdiff