-#LyX 1.2 created this file. For more info see http://www.lyx.org/
-\lyxformat 220
+#LyX 1.3 created this file. For more info see http://www.lyx.org/
+\lyxformat 221
\textclass article
+\begin_preamble
+\usepackage[
+ pdftitle={SDCC Compiler User Guide},
+ pdfauthor={SDCC development team},
+ pdfsubject={installation, user manual},
+ pdfkeywords={8032, 8051, ansi, c, compiler, CPU, DS390,
+ embedded, GPL, manual, mcs51, PIC, small, Z80},
+ colorlinks=true,
+ linkcolor=blue] {hyperref}
+\date{}
+\end_preamble
\language english
\inputencoding default
\fontscheme pslatex
\spacing single
\papersize Default
\paperpackage a4
-\use_geometry 0
+\use_geometry 1
\use_amsmath 0
\use_natbib 0
\use_numerical_citations 0
\paperorientation portrait
+\leftmargin 30mm
+\topmargin 10mm
+\rightmargin 25mm
+\bottommargin 15mm
\secnumdepth 3
\tocdepth 3
\paragraph_separation indent
\layout Comment
Please note: double dashed longoptions (e.g.
- --version) need three dashes in this document to be visable in html and
- pdf output.
+ --version) are written this way: -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-
+\layout Comment
+
+Two resp.
+ three consecutive dashes simply result in a long resp.
+ extra long dash.
+\layout Comment
+
+This document would need some rework: The Installation section is much to
+
+\layout Comment
+
+intimidating (as is the section about sdcdb).
+\layout Comment
+
+Architecture specific stuff (like memory models, code examples) should maybe
+ go
+\layout Comment
+
+into seperate sections/chapters/appendices (it is hard to document PIC or
+ Z80 in
+\layout Comment
+
+a 8051 centered document)
\layout Title
SDCC Compiler User Guide
+\layout Comment
+
+The strings enclosed in $ are automatically updated by cvs:
+\layout Standard
+\align center
+
+\size footnotesize
+$Date$
+\layout Standard
+\align center
+
+\size footnotesize
+$Revision$
\layout Standard
\layout Section
-
+\pagebreak_top
Introduction
\layout Subsection
Sandeep Dutta
\series default
designed for 8 bit Microprocessors.
- The current version targets Intel MCS51 based Microprocessors(8051,8052,
- 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.
+ The current version targets Intel MCS51 based Microprocessors (8031, 8032,
+ 8051, 8052
+\begin_inset LatexCommand \index{8031, 8032, 8051, 8052 CPU}
+
+\end_inset
+
+, etc), Zilog Z80 based MCUs, and the Dallas DS80C390 variant.
+ It can be retargetted for other microprocessors, support for PIC, 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
\newline
-SDCC also provides an option (--cyclomatic) to report the relative complexity
- of a function.
+SDCC also provides an option (-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-cyclomatic) to report the relative complexity of a function.
These functions can then be further optimized, or hand coded in assembly
if needed.
\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
+.
\series bold
+
+\series default
+\emph on
+Please note: the compiler will probably always be some steps ahead of this
+ documentation
+\series bold
+\emph default
+
+\begin_inset LatexCommand \index{Status of documentation}
+
+\end_inset
+
+
+\begin_inset Foot
+collapsed false
+
+\layout Standard
+
+Obviously this has pros and cons
+\end_inset
+
.
\layout Subsection
This documentation is maintained using a freeware word processor (LyX).
\newline
This program is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the Free
- Software Foundation; either version 2, or (at your option) any later version.
+ under the terms of the GNU General Public License
+\begin_inset LatexCommand \index{GNU General Public License, GPL}
+
+\end_inset
+
+ as published by the Free Software Foundation; either version 2, or (at
+ your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT
- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- FOR A PARTICULAR PURPOSE.
+ ANY WARRANTY; without even the implied warranty
+\begin_inset LatexCommand \index{warranty}
+
+\end_inset
+
+ of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, 59 Temple
\layout Subsection
Typographic conventions
+\begin_inset LatexCommand \index{Typographic conventions}
+
+\end_inset
+
+
\layout Standard
Throughout this manual, we will use the following convention.
This version has numerous bug fixes compared with the previous version.
But we also introduced some incompatibilities with older versions.
Not just for the fun of it, but to make the compiler more stable, efficient
- and ANSI compliant.
+ and ANSI compliant
+\begin_inset LatexCommand \index{ANSI-compliance}
+
+\end_inset
+
+.
\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
will push a as an int and as a char resp.
\layout Itemize
-option ---regextend has been removed
+option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-regextend has been removed
\layout Itemize
-option ---noregparms has been removed
+option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noregparms has been removed
\layout Itemize
-option ---stack-after-data has been removed
+option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-after-data has been removed
\layout Standard
char KernelFunction3(char p) at 0x340;
\newline
+\layout Standard
+
+
+\family typewriter
+code banking
+\begin_inset LatexCommand \index{code banking (not supported)}
+
+\end_inset
+
+ support for mcs51
\newline
\family default
-If you can think of some more, please send them to the list.
-\newline
+If you can think of some more, please see the chapter 9 about filing feature
+ requests
+\begin_inset LatexCommand \index{Requesting features}
-\newline
+\end_inset
-\emph on
-<pending: And then of course a proper index-table
-\begin_inset LatexCommand \index{index}
+
+\begin_inset LatexCommand \index{Feature request}
\end_inset
->
-\layout Section
+.
+\newline
+\layout Section
+\pagebreak_top
Installation
+\begin_inset LatexCommand \index{Installation}
+
+\end_inset
+
+
\layout Subsection
Configure Options
+\begin_inset LatexCommand \index{Options SDCC configuration}
+
+\end_inset
+
+
\layout Standard
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
----prefix see tabel below
+-
+\begin_inset ERT
+status Collapsed
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\layout List
\labelwidthstring 00.00.0000
----exec_prefix see tabel below
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+\layout Standard
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\layout List
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----bindir see tabel below
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----datadir see tabel below
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+\layout Standard
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+\backslash
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\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
\layout List
\labelwidthstring 00.00.0000
----disable-mcs51-port Excludes the Intel mcs51 port
+-
+\begin_inset ERT
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+\layout Standard
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+\backslash
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+\end_inset
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+-disable-mcs51-port Excludes the Intel mcs51 port
\layout List
\labelwidthstring 00.00.0000
----disable-gbz80-port Excludes the Gameboy gbz80 port
+-
+\begin_inset ERT
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+\layout Standard
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+-disable-gbz80-port Excludes the Gameboy gbz80 port
\layout List
\labelwidthstring 00.00.0000
----disable-z80-port Excludes the z80 port
+-
+\begin_inset ERT
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+\layout Standard
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+-z80-port Excludes the z80 port
\layout List
\labelwidthstring 00.00.0000
----disable-avr-port Excludes the AVR port
+-
+\begin_inset ERT
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+-disable-avr-port Excludes the AVR port
\layout List
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+-
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\layout List
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\layout List
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\layout List
\labelwidthstring 00.00.0000
----disable-ucsim Disables configuring and building of ucsim
+-
+\begin_inset ERT
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+\layout Standard
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\layout List
\labelwidthstring 00.00.0000
----disable-device-lib-build Disables automatically building device libraries
+-
+\begin_inset ERT
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+\layout Standard
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\layout List
\labelwidthstring 00.00.0000
----disable-packihx Disables building packihx
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+\begin_inset ERT
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+\layout Standard
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\layout List
\labelwidthstring 00.00.0000
----enable-libgc Use the Bohem memory allocator.
+-
+\begin_inset ERT
+status Collapsed
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+\layout Standard
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+-enable-libgc Use the Bohem memory allocator.
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\layout Standard
Furthermore the environment variables CC, CFLAGS, ...
the tools and their arguments can be influenced.
- Please see `configure ---help` and the man/info pages of `configure` for
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+ Please see `configure -
+\begin_inset ERT
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These defaults are:
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'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
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+\layout Standard
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file.
\layout Subsection
Install paths
-\layout Standard
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+
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-1.
- Binary files (preprocessor, assembler and linker)
-\layout Standard
+\layout Standard
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\begin_inset Tabular
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+<lyxtabular version="3" rows="5" columns="4">
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-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
+Library file**
+\end_inset
+</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
-Path
+
+\emph on
+$DATADIR/$LIB_DIR_SUFFIX
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-default
+/usr/local/share/sdcc/lib
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-Win32 builds
+
+\backslash
+sdcc
+\backslash
+lib
\end_inset
</cell>
</row>
\layout Standard
+Documentation
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
\emph on
-$DATADIR/$LIB_DIR_SUFFIX
+$DOCDIR
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-/usr/local/share/sdcc/lib
+/usr/local/share/sdcc/doc
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\backslash
sdcc
\backslash
-lib
+doc
\end_inset
</cell>
</row>
\end_inset
-\newline
+\layout Verse
-\newline
-4.
- Documentation
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Path
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-default
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-
-\emph on
-$DOCDIR
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-/usr/local/share/sdcc/doc
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-
-\backslash
-sdcc
-\backslash
-doc
-\end_inset
-</cell>
-</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
+\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 Subsection
Search Paths
+\begin_inset LatexCommand \index{Search path}
+
+\end_inset
+
+
\layout Standard
Some search paths or parts of them are determined by configure variables
1.
Binary files (preprocessor, assembler and linker)
\newline
-
+
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
+<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
\newline
-\newline
+\layout Standard
+\noindent
2.
Include files
\newline
-
+
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="1.5in">
<column alignment="block" valignment="top" leftline="true" width="1.5in">
-<column alignment="left" valignment="top" leftline="true" rightline="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
----I dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-I dir
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
----I dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-I dir
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
----I dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-I dir
\end_inset
</cell>
</row>
\newline
-\newline
- The option ---nostdinc disables the last two search paths.
+\layout Standard
+\noindent
+The option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nostdinc disables the last two search paths.
\newline
\newline
3.
Library files
\newline
+
+\layout Standard
+
With the exception of
\begin_inset Quotes sld
\end_inset
----L dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-L dir
\begin_inset Quotes srd
\end_inset
\newline
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="6" columns="3">
<features>
<column alignment="block" valignment="top" leftline="true" width="1.7in">
-<column alignment="left" valignment="top" leftline="true" width="1.2in">
+<column alignment="block" valignment="top" leftline="true" width="1.2in">
<column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
<row topline="true" bottomline="true">
<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
----L dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-L dir
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
----L dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-L dir
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
----L dir
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-L dir
\end_inset
</cell>
</row>
\end_inset
+\newline
+
\layout Comment
Don't delete any of the stray spaces in the table above without checking
\SpecialChar ~
\newline
-The option ---nostdlib disables the last two search paths.
+The option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nostdlib disables the last two search paths.
\layout Subsection
Building SDCC
+\begin_inset LatexCommand \index{Building SDCC}
+
+\end_inset
+
+
\layout Subsubsection
Building SDCC on Linux
./configure CC=gcc2 CXX=g++2
\layout Subsubsection
-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
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
Make sure not to commit files with windows line endings.
\layout Subsubsection
-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}
\newline
\newline
-Download the file UnxUtils.zip.
- Now you have to install the utilities and setup Visual C++ so it can locate
- the required programs.
+Download the file UnxUtils
+\begin_inset LatexCommand \index{UnxUtils}
+
+\end_inset
+
+.zip.
+ 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
bin, and you can compile using sdcc.
\layout Subsubsection
-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:
\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
Type
\family sans
\series bold
-"sdcc ---version"
+"sdcc -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-version"
+\begin_inset LatexCommand \index{version}
+
+\end_inset
+
+
\family default
\series default
at the prompt, and the program should run and tell you the version.
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
header files and libraries.
Edit test.c and change it to the following:
-\series default
-
-\newline
+\layout Verse
-\newline
\family typewriter
#include <string.h>
strcpy(str1, "testing");
\newline
}
-\newline
+\layout Standard
-\newline
-\family default
\series medium
Compile this by typing
\family sans
\series medium
(see the 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 Subsection
Install Trouble-shooting
+\begin_inset LatexCommand \index{Install trouble-shooting}
+
+\end_inset
+
+
\layout Subsubsection
SDCC does not build correctly.
.
\newline
-On most systems you will need super-user privilages to do this.
+On most systems you will need super-user privileges to do this.
\layout Subsection
Components of SDCC
the assembler and linkage editor.
\layout Subsubsection
-sdcpp - The C-Preprocessor
+sdcpp
+\begin_inset LatexCommand \index{sdcpp}
+
+\end_inset
+
+ - The C-Preprocessor
\layout Standard
The preprocessor is a modified version of the GNU preprocessor.
\layout Subsubsection
s51 - The Simulator
+\begin_inset LatexCommand \index{s51}
+
+\end_inset
+
+
\layout Standard
S51 is a freeware, opensource simulator developed by Daniel Drotos (
).
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 support the core mcs51, the Dallas DS80C390 and the Phillips
XA51 family.
\layout Subsubsection
-sdcdb - Source Level Debugger
-\layout Standard
-
+sdcdb
+\begin_inset LatexCommand \index{sdcdb}
-\family typewriter
-\shape italic
-<todo: is this thing still alive?>
-\newline
+\end_inset
-\newline
+ - Source Level Debugger
+\layout Standard
-\family default
-\shape default
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
+ 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 Section
+\pagebreak_top
Using SDCC
\layout Subsection
\series default
This will compile, assemble and link your source file.
Output files are as follows
-\newline
+\layout Itemize
-\newline
-sourcefile.asm - Assembler source file created by the compiler
-\newline
-sourcefile.lst - Assembler listing file created by the Assembler
-\newline
-sourcefile.rst - Assembler listing file updated with linkedit information,
- created by linkage editor
-\newline
-sourcefile.sym - symbol listing for the sourcefile, created by the assembler
-\newline
-sourcefile.rel - Object file created by the assembler, input to Linkage editor
-\newline
-sourcefile.map - The memory map for the load module, created by the Linker
-\newline
-sourcefile.mem - A file with a summary of the memory ussage
-\newline
-sourcefile.ihx - The load module in Intel hex format (you can select the
- Motorola S19 format with ---out-fmt-s19)
-\newline
-sourcefile.adb - An intermediate file containing debug information needed
- to create the .cdb file (with ---debug)
-\newline
-sourcefile.cdb - An optional file (with ---debug) containing debug information
-\newline
-sourcefile. - (no extension) An optional AOMF51 file containing debug
- information (with ---debug)
-\newline
-sourcefile.dump* - Dump file to debug the compiler it self (with ---dumpall)
- (see section
+sourcefile.asm
+\begin_inset LatexCommand \index{.asm}
+
+\end_inset
+
+ - Assembler source
+\begin_inset LatexCommand \index{Assembler source}
+
+\end_inset
+
+ file created by the compiler
+\layout Itemize
+
+sourcefile.lst
+\begin_inset LatexCommand \index{.lst}
+
+\end_inset
+
+ - Assembler listing
+\begin_inset LatexCommand \index{Assembler listing}
+
+\end_inset
+
+ file created by the Assembler
+\layout Itemize
+
+sourcefile.rst
+\begin_inset LatexCommand \index{.rst}
+
+\end_inset
+
+ - Assembler listing
+\begin_inset LatexCommand \index{Assembler listing}
+
+\end_inset
+
+ file updated with linkedit information, created by linkage editor
+\layout Itemize
+
+sourcefile.sym
+\begin_inset LatexCommand \index{.sym}
+
+\end_inset
+
+ - symbol listing
+\begin_inset LatexCommand \index{Symbol listing}
+
+\end_inset
+
+ for the sourcefile, created by the assembler
+\layout Itemize
+
+sourcefile.rel
+\begin_inset LatexCommand \index{.rel}
+
+\end_inset
+
+ - Object file
+\begin_inset LatexCommand \index{Object file}
+
+\end_inset
+
+ created by the assembler, input to Linkage editor
+\layout Itemize
+
+sourcefile.map
+\begin_inset LatexCommand \index{.map}
+
+\end_inset
+
+ - The memory map
+\begin_inset LatexCommand \index{Memory map}
+
+\end_inset
+
+ for the load module, created by the Linker
+\layout Itemize
+
+sourcefile.mem
+\begin_inset LatexCommand \index{.mem}
+
+\end_inset
+
+ - A file with a summary of the memory usage
+\layout Itemize
+
+sourcefile.ihx
+\begin_inset LatexCommand \index{.ihx}
+
+\end_inset
+
+ - The load module in Intel hex format
+\begin_inset LatexCommand \index{Intel hex format}
+
+\end_inset
+
+ (you can select the Motorola S19 format
+\begin_inset LatexCommand \index{Motorola S19 format}
+
+\end_inset
+
+ with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-out-fmt-s19
+\begin_inset LatexCommand \index{-\/-out-fmt-s19}
+
+\end_inset
+
+.
+ If you need another format you might want to use objdump
+\begin_inset LatexCommand \index{objdump}
+
+\end_inset
+
+ or srecord
+\begin_inset LatexCommand \index{srecord}
+
+\end_inset
+
+)
+\layout Itemize
+
+sourcefile.adb
+\begin_inset LatexCommand \index{.adb}
+
+\end_inset
+
+ - An intermediate file containing debug information needed to create the
+ .cdb file (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
+
+\end_inset
+
+)
+\layout Itemize
+
+sourcefile.cdb
+\begin_inset LatexCommand \index{.cdb}
+
+\end_inset
+
+ - An optional file (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug) containing debug information
+\layout Itemize
+
+sourcefile.
+ - (no extension)
+\begin_inset LatexCommand \index{. (no extension)}
+
+\end_inset
+
+ An optional AOMF51 file containing debug information (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug)
+\layout Itemize
+
+sourcefile.dump*
+\begin_inset LatexCommand \index{.dump*}
+
+\end_inset
+
+ - Dump file to debug the compiler it self (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpall) (see section
\begin_inset Quotes sld
\end_inset
\emph on
main()
\emph default
- function and link the files together with the following command:
+ function and link
+\begin_inset LatexCommand \index{Linker}
+
+\end_inset
+
+ the files together with the following command:
\newline
\newline
\family default
\series default
+\begin_inset LatexCommand \index{.rel}
+
+\end_inset
+
+
\newline
\newline
\noun default
file specified in the command line, since the linkage editor processes
file in the order they are presented to it.
+ The linker is invoked from sdcc using a script file with extension .lnk
+\begin_inset LatexCommand \index{.lnk}
+
+\end_inset
+
+.
+ You can view this file to troubleshoot linking problems such as those arising
+ from missing libraries.
\layout Subsubsection
Projects with Additional Libraries
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+
\layout Standard
Some reusable routines may be compiled into a library, see the documentation
for how to create a
\emph on
.lib
+\begin_inset LatexCommand \index{.lib}
+
+\end_inset
+
+
\emph default
library file.
Libraries created in this manner can be included in the command line.
\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{rel}
+
+\end_inset
+
+ files.
For an example see the standard library file
\emph on
libsdcc.lib
\layout Subsection
Command Line Options
+\begin_inset LatexCommand \index{Command Line Options}
+
+\end_inset
+
+
\layout Subsubsection
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 MCS51 (8051) family of processors.
+ Generate code for the 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
-\series default
- Generate code for the DS80C390 processor.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{-mds390}
+
+\end_inset
-\series bold
--mz80
\series default
- Generate code for the Z80 family of processors.
-\layout List
-\labelwidthstring 00.00.0000
+ Generate code for the DS80C390
+\begin_inset LatexCommand \index{DS80C390}
+\end_inset
-\series bold
--mgbz80
-\series default
- Generate code for the GameBoy Z80 processor.
+ processor.
\layout List
\labelwidthstring 00.00.0000
\series bold
--mavr
-\series default
- Generate code for the Atmel AVR processor (In development, not complete).
-\layout List
-\labelwidthstring 00.00.0000
+-mds400
+\begin_inset LatexCommand \index{-mds400}
+
+\end_inset
-\series bold
--mpic14
\series default
- Generate code for the PIC 14-bit processors (In development, not complete).
+ Generate code for the DS80C400
+\begin_inset LatexCommand \index{DS80C400}
+
+\end_inset
+
+ processor.
\layout List
\labelwidthstring 00.00.0000
\series bold
--mtlcs900h
+-mz80
+\begin_inset LatexCommand \index{-mz80}
+
+\end_inset
+
+
\series default
- Generate code for the Toshiba TLCS-900H processor (In development, not
- complete).
+ Generate code for the Z80
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ family of processors.
\layout List
\labelwidthstring 00.00.0000
\series bold
--mxa51
+-mgbz80
+\begin_inset LatexCommand \index{-mgbz80}
+
+\end_inset
+
+
\series default
- Generate code for the Philips XA51 processor (In development, not complete).
-\layout Subsubsection
+ Generate code for the GameBoy Z80
+\begin_inset LatexCommand \index{GameBoy Z80}
-Preprocessor Options
+\end_inset
+
+ processor.
\layout List
\labelwidthstring 00.00.0000
\series bold
--I<path>
+-mavr
+\begin_inset LatexCommand \index{-mavr}
+
+\end_inset
+
+
\series default
- The additional location where the pre processor will look for <..h> or
-\begin_inset Quotes eld
+ Generate code for the Atmel AVR
+\begin_inset LatexCommand \index{AVR}
+
\end_inset
-..h
-\begin_inset Quotes erd
+ 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
- files.
+.
+\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
--D<macro[=value]>
+-mpic14
+\begin_inset LatexCommand \index{-mpic14}
+
+\end_inset
+
+
\series default
- Command line definition of macros.
- Passed to the pre processor.
+ Generate code for the PIC 14
+\begin_inset LatexCommand \index{PIC14}
+
+\end_inset
+
+-bit processors (Microchip p16f84 and variants).
+\layout Comment
+
+p16f627 p16f628 p16f84 p16f873 p16f877?
\layout List
\labelwidthstring 00.00.0000
\series bold
--M
+-mpic16
+\begin_inset LatexCommand \index{-mpic16}
+
+\end_inset
+
+
+\series default
+ Generate code for the PIC 16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+-bit processors (Microchip p18f452 and variants).
+\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 (In development, not complete).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mxa51
+\begin_inset LatexCommand \index{-mxa51}
+
+\end_inset
+
+
+\series default
+ Generate code for the Phillips XA51
+\begin_inset LatexCommand \index{XA51}
+
+\end_inset
+
+ processor (In development, not complete).
+\layout Subsubsection
+
+Preprocessor Options
+\begin_inset LatexCommand \index{Options preprocessor}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Preprocessor options}
+
+\end_inset
+
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-I<path>
+\begin_inset LatexCommand \index{-I<path>}
+
+\end_inset
+
+
+\series default
+ The additional location where the pre processor will look for <..h> or
+\begin_inset Quotes eld
+\end_inset
+
+..h
+\begin_inset Quotes erd
+\end_inset
+
+ files.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-D<macro[=value]>
+\begin_inset LatexCommand \index{-D<macro[=value]>}
+
+\end_inset
+
+
+\series default
+ Command line definition of macros.
+ Passed to the pre processor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-M
+\begin_inset LatexCommand \index{-M}
+
+\end_inset
+
+
\series default
Tell the preprocessor to output a rule suitable for make describing the
dependencies of each object file.
\series bold
-C
+\begin_inset LatexCommand \index{-C}
+
+\end_inset
+
+
\series default
Tell the preprocessor not to discard comments.
Used with the `-E' option.
\series bold
-MM
+\begin_inset LatexCommand \index{-MM}
+
+\end_inset
+
+
\size large
\bar under
\series bold
-Aquestion(answer)
+\begin_inset LatexCommand \index{-Aquestion(answer)}
+
+\end_inset
+
+
\series default
Assert the answer answer for question, in case it is tested with a preprocessor
conditional such as `#if #question(answer)'.
\series bold
-Umacro
+\begin_inset LatexCommand \index{-Umacro}
+
+\end_inset
+
+
\series default
Undefine macro macro.
`-U' options are evaluated after all `-D' options, but before any `-include'
\series bold
-dM
+\begin_inset LatexCommand \index{-dM}
+
+\end_inset
+
+
\series default
Tell the preprocessor to output only a list of the macro definitions that
are in effect at the end of preprocessing.
\series bold
-dD
+\begin_inset LatexCommand \index{-dD}
+
+\end_inset
+
+
\series default
Tell the preprocessor to pass all macro definitions into the output, in
their proper sequence in the rest of the output.
\series bold
-dN
+\begin_inset LatexCommand \index{-dN}
+
+\end_inset
+
+
\size large
\bar under
\layout Subsubsection
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 ~
----lib-path
+-
+\series default
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+-lib-path
+\begin_inset LatexCommand \index{-\/-lib-path}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{-L -\/-lib-path}
+
+\end_inset
+
+
\bar under
\series default
\bar default
<absolute path to additional libraries> This option is passed to the linkage
- editor's additional libraries search path.
+ editor's additional libraries
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+ search path.
The path name must be absolute.
Additional library files may be specified in the command line.
See section Compiling programs for more details.
\series bold
----xram-loc
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xram-loc
\series default
-<Value> The start location of the external ram, default value is 0.
- The value entered can be in Hexadecimal or Decimal format, e.g.: ---xram-loc
- 0x8000 or ---xram-loc 32768.
+
+\begin_inset LatexCommand \index{-\/-xram-loc}
+
+\end_inset
+
+<Value> The start location of the external ram
+\begin_inset LatexCommand \index{xdata}
+
+\end_inset
+
+, default value is 0.
+ The value entered can be in Hexadecimal or Decimal format, e.g.: -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xram-loc 0x8000 or -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xram-loc 32768.
\layout List
\labelwidthstring 00.00.0000
\series bold
----code-loc
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-code-loc
\series default
-<Value> The start location of the code segment, default value 0.
+
+\begin_inset LatexCommand \index{-\/-code-loc}
+
+\end_inset
+
+<Value> The start location of the code
+\begin_inset LatexCommand \index{code}
+
+\end_inset
+
+ segment, default value 0.
Note when this option is used the interrupt vector table is also relocated
to the given address.
- The value entered can be in Hexadecimal or Decimal format, e.g.: ---code-loc
- 0x8000 or ---code-loc 32768.
+ The value entered can be in Hexadecimal or Decimal format, e.g.: -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-code-loc 0x8000 or -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-code-loc 32768.
\layout List
\labelwidthstring 00.00.0000
\series bold
----stack-loc
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-loc
\series default
-<Value> By default the stack is placed after the data segment.
+
+\begin_inset LatexCommand \index{-\/-stack-loc}
+
+\end_inset
+
+<Value> By default the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ is placed after the data segment.
Using this option the stack can be placed anywhere in the internal memory
space of the 8051.
The value entered can be in Hexadecimal or Decimal format, e.g.
- ---stack-loc 0x20 or ---stack-loc 32.
+ -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-loc 0x20 or -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-loc 32.
Since the sp register is incremented before a push or call, the initial
sp will be set to one byte prior the provided value.
The provided value should not overlap any other memory areas such as used
\series bold
----data-loc
-\series default
-<Value> The start location of the internal ram data segment.
- The value entered can be in Hexadecimal or Decimal format, eg.
- ---data-loc 0x20 or ---data-loc 32.
- (By default, the start location of the internal ram data segment is set
- as low as possible in memory, taking into account the used register banks
- and the bit segment at address 0x20.
- For example if register banks 0 and 1 are used without bit variables, the
- data segment will be set, if ---data-loc is not used, to location 0x10.)
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----idata-loc
+\backslash
+/
+\end_inset
+
+-data-loc
\series default
-<Value> The start location of the indirectly addressable internal ram, default
- value is 0x80.
- The value entered can be in Hexadecimal or Decimal format, eg.
- ---idata-loc 0x88 or ---idata-loc 136.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{-\/-data-loc}
-\series bold
----out-fmt-ihx
-\bar under
-
-\series default
-\bar default
-The linker output (final object code) is in Intel Hex format.
- (This is the default option).
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
+
+<Value> The start location of the internal ram data
+\begin_inset LatexCommand \index{data}
+
+\end_inset
+
+ segment.
+ The value entered can be in Hexadecimal or Decimal format, eg.
+ -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-data-loc 0x20 or -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-data-loc 32.
+ (By default, the start location of the internal ram data segment is set
+ as low as possible in memory, taking into account the used register banks
+ and the bit segment at address 0x20.
+ For example if register banks 0 and 1 are used without bit variables, the
+ data segment will be set, if -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-data-loc is not used, to location 0x10.)
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-idata-loc
+\series default
+
+\begin_inset LatexCommand \index{-\/-idata-loc}
+
+\end_inset
+
+<Value> The start location of the indirectly addressable internal ram
+\begin_inset LatexCommand \index{idata}
+
+\end_inset
+
+, default value is 0x80.
+ The value entered can be in Hexadecimal or Decimal format, eg.
+ -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-idata-loc 0x88 or -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-idata-loc 136.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-out-fmt-ihx
+\begin_inset LatexCommand \index{-\/-out-fmt-ihx}
+
+\end_inset
+
+
+\bar under
+
+\series default
+\bar default
+The linker output (final object code) is in Intel Hex format.
+\begin_inset LatexCommand \index{Intel hex format}
+
+\end_inset
+
+ (This is the default option).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-out-fmt-s19
+\begin_inset LatexCommand \index{-\/-out-fmt-s19}
+
+\end_inset
-\series bold
----out-fmt-s19
\bar under
\series default
\bar default
-The linker output (final object code) is in Motorola S19 format.
+The linker output (final object code) is in Motorola S19 format
+\begin_inset LatexCommand \index{Motorola S19 format}
+
+\end_inset
+
+.
\layout Subsubsection
MCS51 Options
+\begin_inset LatexCommand \index{Options MCS51}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{MCS51 options}
+
+\end_inset
+
+
\layout List
\labelwidthstring 00.00.0000
\series bold
----model-large
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-large
+\begin_inset LatexCommand \index{-\/-model-large}
+
+\end_inset
+
+
\series default
Generate code for Large model programs see section Memory Models for more
details.
\series bold
----model-small
+-
+\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
\layout Subsubsection
DS390 Options
+\begin_inset LatexCommand \index{Options DS390}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{DS390 options}
+
+\end_inset
+
+
\layout List
\labelwidthstring 00.00.0000
\series bold
----model-flat24
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-flat24
\series default
+
+\begin_inset LatexCommand \index{-\/-model-flat24}
+
+\end_inset
+
+
\size large
\emph on
\series bold
----stack-10bit
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-10bit
\series default
+
+\begin_inset LatexCommand \index{-\/-stack-10bit}
+
+\end_inset
+
Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
This is the one and only that the ds390 code generator supports right now
and is default when using
any re-entrant functions compiled with this option.
In principle, this should work with the
\emph on
----stack-auto
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
\emph default
option, but that has not been tested.
It is incompatible with the
\emph on
----xstack
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+
\emph default
option.
It also only makes sense if the processor is in 24 bit contiguous addressing
mode (see the
\emph on
----model-flat24 option
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-flat24 option
\emph default
).
\layout Subsubsection
-Optimization Options
-\layout List
-\labelwidthstring 00.00.0000
+Z80 Options
+\begin_inset LatexCommand \index{Options Z80}
+\end_inset
-\series bold
----nogcse
-\series default
- Will not do global subexpression elimination, this option may be used when
- the compiler creates undesirably large stack/data spaces to store compiler
- 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 can be used
- to turn off global subexpression elimination for a given function only.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{Z80 options}
-\series bold
----noinvariant
-\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 can be used
- to turn off invariant optimizations for a given function only.
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
-\series bold
----noinduction
-\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 can be used to turn off induction optimizations for a given function
- only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----nojtbound
-\size large
-\bar under
-
-\series default
-\size default
-\bar default
- Will not generate boundary condition check when switch statements are implement
-ed using jump-tables.
- See section Switch Statements for more details.
- It is recommended that this option is NOT used, #pragma\SpecialChar ~
-NOJTBOUND can be
- used to turn off boundary checking for jump tables for a given function
- only.
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----noloopreverse
+\backslash
+/
+\end_inset
+
+-callee-saves-bc
\series default
+
+\begin_inset LatexCommand \index{-\/-callee-saves-bc}
+
+\end_inset
+
+
\size large
+\emph on
\size default
-Will not do loop reversal optimization.
+\emph default
+Force a called function to always save BC.
\layout List
\labelwidthstring 00.00.0000
----
+
\series bold
-nolabelopt
-\series default
- Will not optimize labels (makes the dumpfiles more readable).
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----no-xinit-opt
+\backslash
+/
+\end_inset
+
+-no-std-crt0
\series default
- Will not memcpy initialized data in far space from code space.
- This saves a few bytes in code space if you don't have initialized data.
+
+\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 Subsubsection
-Other Options
-\layout List
-\labelwidthstring 00.00.0000
+Optimization Options
+\begin_inset LatexCommand \index{Options optimization}
+\end_inset
-\series bold
--c\SpecialChar ~
----compile-only
-\series default
- will compile and assemble the source, but will not call the linkage editor.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{Optimization options}
-\series bold
---c1mode
-\series default
- reads the preprocessed source from standard input and compiles it.
- The file name for the assembler output must be specified using the -o option.
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
-\series bold
--E
-\series default
- Run only the C preprocessor.
- Preprocess all the C source files specified and output the results to standard
- output.
\layout List
\labelwidthstring 00.00.0000
\series bold
--o\SpecialChar ~
-<path/file>
-\series default
-The output path resp.
- file where everything will be placed.
- If the parameter is a path, it must have a trailing slash (or backslash
- for the Windows binaries) to be recognized as a path.
-
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----stack-auto
-\series default
-\size large
-\emph on
-
-\size default
-\emph default
-All functions in the source file will be compiled as
-\emph on
-reentrant
-\emph default
-, i.e.
- the parameters and local variables will be allocated on the stack.
- see section Parameters and Local Variables for more details.
- If this option is used all source files in the project should be compiled
- with this option.
-
-\layout List
-\labelwidthstring 00.00.0000
+\backslash
+/
+\end_inset
+
+-nogcse
+\begin_inset LatexCommand \index{-\/-nogcse}
+
+\end_inset
-\series bold
----xstack
\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
+ Will not do global subexpression elimination, this option may be used when
+ the compiler creates undesirably large stack/data spaces to store compiler
+ 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}
+\end_inset
-\series bold
----callee-saves function1[,function2][,function3]....
+ can be used to turn off global subexpression elimination
+\begin_inset LatexCommand \index{Subexpression elimination}
-\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
- to determine the appropriate scheme to use for each function call.
- DO NOT use this option for built-in functions such as _muluint..., if this
- option is used for a library function the appropriate library function
- needs to be recompiled with the same option.
- If the project consists of multiple source files then all the source file
- should be compiled with the same ---callee-saves option string.
- Also see #pragma\SpecialChar ~
-CALLEE-SAVES.
+\end_inset
+
+ for a given function only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----debug
-\bar under
-
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noinvariant
+\begin_inset LatexCommand \index{-\/-noinvariant}
+
+\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.
- For more information see documentation for SDCDB.
+ 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}
+
+\end_inset
+
+ can be used to turn off invariant optimizations for a given function only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----peep-file
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noinduction
+\begin_inset LatexCommand \index{-\/-noinduction}
+
+\end_inset
+
+
\series default
-<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.
+ 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}
+
+\end_inset
+
+ can be used to turn off induction optimizations for a given function only.
\layout List
\labelwidthstring 00.00.0000
\series bold
--S
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nojtbound
+\begin_inset LatexCommand \index{-\/-nojtbound}
+
+\end_inset
+
+
\size large
\bar under
\series default
\size default
\bar default
-Stop after the stage of compilation proper; do not assemble.
- The output is an assembler code file for the input file specified.
-\layout List
-\labelwidthstring 00.00.0000
+ Will not generate boundary condition check when switch statements
+\begin_inset LatexCommand \index{switch statement}
+\end_inset
-\series bold
--Wa_asmOption[,asmOption]
-\series default
-...
- Pass the asmOption to the assembler.
-\layout List
-\labelwidthstring 00.00.0000
+ are implemented using jump-tables.
+ See section Switch Statements for more details.
+ It is recommended that this option is NOT used, #pragma\SpecialChar ~
+NOJTBOUND
+\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+\end_inset
-\series bold
--Wl_linkOption[,linkOption]
-\series default
-...
- Pass the linkOption to the linker.
+ can be used to turn off boundary checking for jump tables for a given function
+ only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----int-long-reent
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noloopreverse
+\begin_inset LatexCommand \index{-\/-noloopreverse}
+
+\end_inset
+
+
\series default
\size large
\size default
- Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
- Note by default these libraries are compiled as non-reentrant.
- See section Installation for more details.
-\layout List
-\labelwidthstring 00.00.0000
+Will not do loop reversal
+\begin_inset LatexCommand \index{Loop reversing}
+\end_inset
-\series bold
----cyclomatic
-\bar under
-
-\series default
-\bar default
-This option will cause the compiler to generate an information message for
- each function in the source file.
- The message contains some
-\emph on
-important
-\emph default
- information about the function.
- The number of edges and nodes the compiler detected in the control flow
- graph of the function, and most importantly the
-\emph on
-cyclomatic complexity
-\emph default
- see section on Cyclomatic Complexity for more details.
+optimization.
\layout List
\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
-\series bold
----float-reent
-\bar under
-
-\series default
-\bar default
- Floating point library is compiled as reentrant.See section Installation
- for more details.
-\layout List
-\labelwidthstring 00.00.0000
+\layout Standard
+\backslash
+/
+\end_inset
+-
\series bold
----nooverlay
+nolabelopt
\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
+
+\begin_inset LatexCommand \index{-\/-nolabelopt }
+\end_inset
-\series bold
----main-return
-\series default
- This option can be used when the code generated is called by a monitor
- program.
- The compiler will generate a 'ret' upon return from the 'main' function.
- The default option is to lock up i.e.
- generate a 'ljmp '.
+Will not optimize labels (makes the dumpfiles more readable).
\layout List
\labelwidthstring 00.00.0000
\series bold
----no-peep
-\series default
- Disable peep-hole optimization.
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----peep-asm
-\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 rules defined in the source file tree '<target>/peeph.def
-' before using this option.
-\layout List
-\labelwidthstring 00.00.0000
+\backslash
+/
+\end_inset
+
+-no-xinit-opt
+\begin_inset LatexCommand \index{-\/-no-xinit-opt}
+
+\end_inset
-\series bold
----iram-size
\series default
-<Value> Causes the linker to check if the internal ram usage is within limits
- of the given value.
-\layout List
-\labelwidthstring 00.00.0000
+ Will not memcpy initialized data in far space from code space.
+ This saves a few bytes in code space if you don't have initialized data.
+\layout Subsubsection
+Other Options
+\begin_inset LatexCommand \index{Options other}
-\series bold
----xram-size
-\series default
-<Value> Causes the linker to check if the external ram usage is within limits
- of the given value.
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
-\series bold
----code-size
-\series default
-<Value> Causes the linker to check if the code usage is within limits of
- the given value.
\layout List
\labelwidthstring 00.00.0000
\series bold
----nostdincl
-\series default
- This will prevent the compiler from passing on the default include path
- to the preprocessor.
-\layout List
-\labelwidthstring 00.00.0000
-
+-c\SpecialChar ~
+-
+\begin_inset ERT
+status Collapsed
-\series bold
----nostdlib
-\series default
- This will prevent the compiler from passing on the default library path
- to the linker.
-\layout List
-\labelwidthstring 00.00.0000
+\layout Standard
+\backslash
+/
+\end_inset
-\series bold
----verbose
-\series default
- Shows the various actions the compiler is performing.
-\layout List
-\labelwidthstring 00.00.0000
+-compile-only
+\begin_inset LatexCommand \index{-\/-compile-only}
+\end_inset
-\series bold
--V
-\series default
- Shows the actual commands the compiler is executing.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{-c -\/-compile-only}
-\series bold
----no-c-code-in-asm
-\series default
- 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
-\series bold
----i-code-in-asm
\series default
- Include i-codes in the asm file.
- Sounds like noise but is most helpfull for debugging the compiler itself.
+ will compile and assemble the source, but will not call the linkage editor.
\layout List
\labelwidthstring 00.00.0000
\series bold
----less-pedantic
+-
\series default
- Disable some of the more pedantic warnings (jwk burps: please be more specific
- here, please!)
-\layout List
-\labelwidthstring 00.00.0000
-
-\series bold
----print-search-dirs
-\series default
- Display the directories in the compiler's search path
-\layout Subsubsection
+\begin_inset ERT
+status Collapsed
-Intermediate Dump Options
\layout Standard
-The following options are provided for the purpose of retargetting and debugging
- the compiler.
- These provided a means to dump the intermediate code (iCode) generated
- by the compiler in human readable form at various stages of the compilation
- process.
-
-\layout List
-\labelwidthstring 00.00.0000
+\backslash
+/
+\end_inset
\series bold
----dumpraw
-\series default
- This option will cause the compiler to dump the intermediate code into
- a file of named
-\emph on
-<source filename>.dumpraw
-\emph default
- just after the intermediate code has been generated for a function, i.e.
- before any optimizations are done.
- The basic blocks at this stage ordered in the depth first number, so they
- may not be in sequence of execution.
-\layout List
-\labelwidthstring 00.00.0000
+-c1mode
+\begin_inset LatexCommand \index{-\/-c1mode}
+
+\end_inset
-\series bold
----dumpgcse
\series default
- Will create a dump of iCode's, after global subexpression elimination,
- into a file named
-\emph on
-<source filename>.dumpgcse.
+ reads the preprocessed source from standard input and compiles it.
+ The file name for the assembler output must be specified using the -o option.
\layout List
\labelwidthstring 00.00.0000
\series bold
----dumpdeadcode
+-E
+\begin_inset LatexCommand \index{-E}
+
+\end_inset
+
+
\series default
- Will create a dump of iCode's, after deadcode elimination, into a file
- named
-\emph on
-<source filename>.dumpdeadcode.
+ Run only the C preprocessor.
+ Preprocess all the C source files specified and output the results to standard
+ output.
\layout List
\labelwidthstring 00.00.0000
\series bold
----dumploop
-\series default
-\size large
+-o\SpecialChar ~
+<path/file>
+\begin_inset LatexCommand \index{-o <path/file>}
+
+\end_inset
+
-\size default
-Will create a dump of iCode's, after loop optimizations, into a file named
+\series default
+The output path resp.
+ file where everything will be placed.
+ If the parameter is a path, it must have a trailing slash (or backslash
+ for the Windows binaries) to be recognized as a path.
-\emph on
-<source filename>.dumploop.
\layout List
\labelwidthstring 00.00.0000
\series bold
----dumprange
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
\series default
\size large
+\emph on
\size default
-Will create a dump of iCode's, after live range analysis, into a file named
-
+\emph default
+All functions in the source file will be compiled as
\emph on
-<source filename>.dumprange.
-\layout List
-\labelwidthstring 00.00.0000
+reentrant
+\emph default
+\begin_inset LatexCommand \index{reentrant}
-\series bold
----dumlrange
-\series default
- Will dump the life ranges for all symbols.
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
+
+, i.e.
+ the parameters and local variables will be allocated on the stack
+\begin_inset LatexCommand \index{stack}
+\end_inset
-\series bold
----dumpregassign
-\bar under
-
-\series default
-\bar default
-Will create a dump of iCode's, after register assignment, into a file named
+.
+ see section Parameters and Local Variables for more details.
+ If this option is used all source files in the project should be compiled
+ with this option.
-\emph on
-<source filename>.dumprassgn.
\layout List
\labelwidthstring 00.00.0000
\series bold
----dumplrange
-\series default
- Will create a dump of the live ranges of iTemp's
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
----dumpall
-\size large
-\bar under
-
-\series default
-\size default
-\bar default
-Will cause all the above mentioned dumps to be created.
-\layout Subsection
+\backslash
+/
+\end_inset
-Environment variables
-\layout Standard
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
-SDCC recognizes the following environment variables:
-\layout List
-\labelwidthstring 00.00.0000
+\end_inset
-\series bold
-SDCC_LEAVE_SIGNALS
\series default
- SDCC installs a signal handler 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.
+ 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
\series bold
-TMP,\SpecialChar ~
-TEMP,\SpecialChar ~
-TMPDIR
-\series default
- Path, where temporary files will be created.
- The order of the variables is the search order.
- In a standard *nix environment these variables are not set, and there's
- no need to set them.
- On Windows it's recommended to set one of them.
-\layout List
-\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series bold
-SDCC_HOME
-\series default
- Path, see
-\begin_inset Quotes sld
+\backslash
+/
\end_inset
-2.3 Install and search paths
-\begin_inset Quotes srd
+-callee-saves
+\begin_inset LatexCommand \index{-\/-callee-saves}
+
\end_inset
-.
-\layout List
-\labelwidthstring 00.00.0000
+\begin_inset LatexCommand \index{function prologue}
+
+\end_inset
+
+ function1[,function2][,function3]....
-\series bold
-SDCC_INCLUDE
\series default
- Path, see
-\begin_inset Quotes sld
+ 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 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
+ needs to be recompiled with the same option.
+ If the project consists of multiple source files then all the source file
+ should be compiled with the same -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
\end_inset
-2.3 Install and search paths
-\begin_inset Quotes srd
+-callee-saves option string.
+ Also see #pragma\SpecialChar ~
+CALLEE-SAVES
+\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+
\end_inset
.
\series bold
-SDCC_LIB
-\series default
- Path, see
-\begin_inset Quotes sld
-\end_inset
-
-2.3 Install and search paths
-\begin_inset Quotes srd
-\end_inset
+-
+\begin_inset ERT
+status Collapsed
-.
\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.
-\layout Subsection
+\backslash
+/
+\end_inset
-MCS51/DS390 Storage Class Language Extensions
-\layout Standard
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
-In addition to the ANSI storage classes SDCC allows the following MCS51
- specific storage classes.
-\layout Subsubsection
+\end_inset
-xdata
-\layout Standard
-Variables declared with this storage class will be placed in the extern
- RAM.
- This is the
-\series bold
-default
+\bar under
+
\series default
- storage class for Large Memory model, e.g.:
-\newline
+\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.
+ For more information see documentation for SDCDB.
+\layout List
+\labelwidthstring 00.00.0000
-\newline
-\family typewriter
-xdata unsigned char xduc;
-\layout Subsubsection
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-data
\layout Standard
-This is the
-\series bold
-default
+\backslash
+/
+\end_inset
+
+-peep-file
\series default
- storage class for Small Memory model.
- Variables declared with this storage class will be allocated in the internal
- RAM, e.g.:
-\newline
-\newline
+\begin_inset LatexCommand \index{-\/-peep-file}
-\family typewriter
-data int iramdata;
-\layout Subsubsection
+\end_inset
-idata
-\layout Standard
+<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.
+\layout List
+\labelwidthstring 00.00.0000
-Variables declared with this storage class will be allocated into the indirectly
- addressable portion of the internal ram of a 8051, e.g.:
-\newline
-\newline
+\series bold
+-S
+\begin_inset LatexCommand \index{-S}
-\family typewriter
-idata int idi;
-\layout Subsubsection
+\end_inset
-bit
-\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
+\size large
+\bar under
+
+\series default
+\size default
+\bar default
+Stop after the stage of compilation proper; do not assemble.
+ The output is an assembler code file for the input file specified.
+\layout List
+\labelwidthstring 00.00.0000
-\newline
-\family typewriter
-bit iFlag;
-\layout Subsubsection
+\series bold
+-Wa_asmOption[,asmOption]
+\series default
-sfr / sbit
-\layout Standard
+\begin_inset LatexCommand \index{-Wa\_asmOption[,asmOption]}
-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
+\end_inset
-\newline
+...
+ Pass the asmOption to the assembler.
+\layout List
+\labelwidthstring 00.00.0000
-\family typewriter
-sfr at 0x80 P0; /* special function register P0 at location 0x80 */
-\newline
-sbit at 0xd7 CY; /* CY (Carry Flag) */
-\layout Subsection
-Pointers
-\layout Standard
+\series bold
+-Wl_linkOption[,linkOption]
+\series default
-SDCC allows (via language extensions) pointers to explicitly point to any
- of the memory spaces of the 8051.
- In addition to the explicit pointers, the compiler uses (by default) generic
- pointers which can be used to point to any of the memory spaces.
-\newline
+\begin_inset LatexCommand \index{-Wl\_linkOption[,linkOption]}
-\newline
-Pointer declaration examples:
-\newline
+\end_inset
-\size small
+...
+ Pass the linkOption to the linker.
+\layout List
+\labelwidthstring 00.00.0000
-\newline
-\family typewriter
-\size default
-/* pointer physically in xternal ram pointing to object in internal ram
- */
-\newline
-data unsigned char * xdata p;
-\newline
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-\newline
-/* pointer physically in code rom pointing to data in xdata space */
-\newline
-xdata unsigned char * code p;
-\newline
+\layout Standard
-\newline
-/* pointer physically in code space pointing to data in code space */
-\newline
-code unsigned char * code p;
-\newline
+\backslash
+/
+\end_inset
-\newline
-/* the folowing is a generic pointer physically located in xdata space */
-\newline
-char * xdata p;
-\family default
-\size small
+-int-long-reent
+\begin_inset LatexCommand \index{-\/-int-long-reent}
-\newline
+\end_inset
-\newline
-\size default
-Well you get the idea.
-
-\newline
+\series default
+ Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
+ Note by default these libraries are compiled as non-reentrant.
+ See section Installation for more details.
+\layout List
+\labelwidthstring 00.00.0000
-\newline
-All unqualified pointers are treated as 3-byte (4-byte for the ds390)
-\emph on
-generic
-\emph default
- pointers.
-
-\size small
-\newline
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-\newline
+\layout Standard
-\size default
-The highest order byte of the
-\emph on
-generic
-\emph default
- pointers contains the data space information.
- Assembler support routines are called whenever data is stored or retrieved
- using
-\emph on
-generic
-\emph default
- pointers.
- These are useful for developing reusable library routines.
- Explicitly specifying the pointer type will generate the most efficient
- code.
-\layout Subsection
+\backslash
+/
+\end_inset
-Parameters & Local Variables
-\layout Standard
+-cyclomatic
+\begin_inset LatexCommand \index{-\/-cyclomatic}
-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
-\emph default
- so by default functions are non-reentrant.
-\newline
+\end_inset
-\newline
-They can be placed on the stack either by using the
+
+\bar under
+
+\series default
+\bar default
+This option will cause the compiler to generate an information message for
+ each function in the source file.
+ The message contains some
\emph on
- ---stack-auto
+important
\emph default
- option or by using the
+ information about the function.
+ The number of edges and nodes the compiler detected in the control flow
+ graph of the function, and most importantly the
\emph on
-reentrant
+cyclomatic complexity
+\begin_inset LatexCommand \index{Cyclomatic complexity}
+
+\end_inset
+
+
\emph default
- keyword in the function declaration, e.g.:
-\newline
+ see section on Cyclomatic Complexity for more details.
+\layout List
+\labelwidthstring 00.00.0000
-\size small
-\newline
+\series bold
+-
+\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
-\emph on
-reentrant
-\emph default
-keyword or the
-\emph on
- ---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
-does not
-\emph default
- mean that the function is register bank independent.
-\newline
+-float-reent
+\begin_inset LatexCommand \index{-\/-float-reent}
-\newline
-Local variables can be assigned storage classes and absolute addresses,
- e.g.:
-\newline
+\end_inset
-\newline
-\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 ~
-...
+\bar under
-\newline
-}
-\newline
-
-\newline
-
-\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
-\emph on
- j
-\emph default
- in internal ram.
- When compiled with
-\emph on
----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
+\series default
+\bar default
+ Floating point library is compiled as reentrant
+\begin_inset LatexCommand \index{reentrant}
-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
+\end_inset
-Overlaying
-\layout Standard
+.See section Installation for more details.
+\layout List
+\labelwidthstring 00.00.0000
-For non-reentrant 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 is small.
-\emph default
- If an explicit storage class is specified for a local variable, it will
- NOT be overlayed.
-\layout Standard
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-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 if they are not reentrant.
\layout Standard
-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
-Parameters and Local variables of functions that contain 16 or 32 bit multiplica
-tion or division will NOT be overlayed since these are implemented using
- external functions, e.g.:
-\newline
+-nooverlay
+\begin_inset LatexCommand \index{-\/-nooverlay}
-\newline
+\end_inset
-\family typewriter
-#pragma SAVE
-\newline
-#pragma NOOVERLAY
-\newline
-void set_error(unsigned char errcd)
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-P3 = errcd;
-\newline
-}
-\newline
-#pragma RESTORE
-\newline
-\newline
-void some_isr () interrupt 2 using 1
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-set_error(10);
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-}
-\newline
+\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
-\newline
-\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
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-Interrupt Service Routines
\layout Standard
-SDCC allows interrupt service routines to be coded in C, with some extended
- keywords.
-\newline
-
-\newline
+\backslash
+/
+\end_inset
-\family typewriter
-void timer_isr (void) interrupt 2 using 1
-\newline
-{
-\newline
-..
-
-\newline
-}
-\newline
+-main-return
+\begin_inset LatexCommand \index{-\/-main-return}
-\newline
+\end_inset
-\family default
-The number following the
-\emph on
-interrupt
-\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 if it is not reentrant.
- A special note here, int (16 bit) and long (32 bit) integer division, multiplic
-ation & modulus 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
- ---stack-auto
-\emph default
- option and the source file will need to be compiled using the
-\emph on
----int-long-ren
-\emph default
-t compiler option.
-\layout Standard
-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
-.
-\layout Standard
+\series default
+ This option can be used when the code generated is called by a monitor
+ program.
+ The compiler will generate a 'ret' upon return from the 'main'
+\begin_inset LatexCommand \index{main return}
-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
+ function.
+ The default option is to lock up i.e.
+ generate a 'ljmp '.
+\layout List
+\labelwidthstring 00.00.0000
-\begin_inset Tabular
-<lyxtabular version="3" rows="6" 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
+\series bold
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-Interrupt #
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-no-peep
+\begin_inset LatexCommand \index{-\/-no-peep}
-Description
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
-Vector Address
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+\series default
+ Disable peep-hole optimization.
+\layout List
+\labelwidthstring 00.00.0000
-\layout Standard
-0
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+\series bold
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-External 0
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
-0x0003
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
-1
+\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
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+ rules defined in the source file tree '<target>/peeph.def' before using
+ this option.
+\layout List
+\labelwidthstring 00.00.0000
-Timer 0
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-0x000B
+\backslash
+/
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-iram-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-iram-size<Value>}
-2
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+
+ 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
-External 1
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-xram-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-xram-size<Value>}
-0x0013
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+
+ 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
-3
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-code-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-code-size<Value>}
-Timer 1
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+
+ Causes the linker to check if the code usage is within limits of the given
+ value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-0x001B
+\backslash
+/
\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
+-nostdincl
+\begin_inset LatexCommand \index{-\/-nostdincl}
-4
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+
+
+\series default
+ This will prevent the compiler from passing on the default include path
+ to the preprocessor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-Serial
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-nostdlib
+\begin_inset LatexCommand \index{-\/-nostdlib}
-0x0023
\end_inset
-</cell>
-</row>
-</lyxtabular>
+
+
+\series default
+ This will prevent the compiler from passing on the default library
+\begin_inset LatexCommand \index{Libraries}
\end_inset
+ path to the linker.
+\layout List
+\labelwidthstring 00.00.0000
-\newline
-\newline
-If the interrupt service routine is defined without
-\emph on
-using
-\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
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-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
+\backslash
+/
+\end_inset
-\newline
-Also see the _naked modifier.
-\layout Subsection
+-verbose
+\begin_inset LatexCommand \index{-\/-verbose}
-Critical Functions
-\layout Standard
+\end_inset
-\shape italic
-<TODO: this isn't implemented at all!>
-\shape default
+\series default
+ Shows the various actions the compiler is performing.
+\layout List
+\labelwidthstring 00.00.0000
-\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
+\series bold
+-V
+\begin_inset LatexCommand \index{-V}
-\size small
+\end_inset
-\newline
-\family typewriter
-\size default
-int foo () critical
-\newline
-{
-\newline
-...
-
-\newline
-...
-
-\newline
-}
-\newline
+\series default
+ Shows the actual commands the compiler is executing.
+\layout List
+\labelwidthstring 00.00.0000
-\family default
-\newline
-The critical attribute maybe used with other attributes like
-\emph on
-reentrant.
-\layout Subsection
+\series bold
+-
+\begin_inset ERT
+status Collapsed
-Naked Functions
\layout Standard
-A special keyword may be associated with a function declaring it as
-\emph on
-_naked.
-
-\emph default
-The
-\emph on
-_naked
-\emph default
- function modifier attribute prevents the compiler from generating prologue
- and epilogue 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:
-\newline
+\backslash
+/
+\end_inset
-\newline
+-no-c-code-in-asm
+\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
-\family typewriter
-data unsigned char counter;
-\newline
-void simpleInterrupt(void) interrupt 1
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-counter++;
-\newline
-}
-\newline
+\end_inset
-\newline
-void nakedInterrupt(void) interrupt 2 _naked
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
+
+\series default
+ Hides your ugly and inefficient c-code from the asm file, so you can always
+ blame the compiler :).
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-i-code-in-asm
+\begin_inset LatexCommand \index{-\/-i-code-in-asm}
+
+\end_inset
+
+
+\series default
+ 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
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-less-pedantic
+\begin_inset LatexCommand \index{-\/-less-pedantic}
+
+\end_inset
+
+
+\series default
+ Disable some of the more pedantic warnings (jwk burps: please be more specific
+ here, please!)
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-print-search-dirs
+\begin_inset LatexCommand \index{-\/-print-search-dirs}
+
+\end_inset
+
+
+\series default
+ Display the directories in the compiler's search path
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-vc
+\begin_inset LatexCommand \index{-\/-vc}
+
+\end_inset
+
+
+\series default
+ Display errors and warnings using MSVC style, so you can use SDCC with
+ visual studio
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-use-stderr
+\begin_inset LatexCommand \index{-\/-use-stdout}
+
+\end_inset
+
+
+\series default
+ Send errors and warnings to stdout instead of stderr
+\layout Subsubsection
+
+Intermediate Dump Options
+\begin_inset LatexCommand \index{Options intermediate dump}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Intermediate dump options}
+
+\end_inset
+
+
+\layout Standard
+
+The following options are provided for the purpose of retargetting and debugging
+ the compiler.
+ These provided a means to dump the intermediate code (iCode
+\begin_inset LatexCommand \index{iCode}
+
+\end_inset
+
+) generated by the compiler in human readable form at various stages of
+ the compilation process.
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpraw
+\begin_inset LatexCommand \index{-\/-dumpraw}
+
+\end_inset
+
+
+\series default
+ This option will cause the compiler to dump the intermediate code into
+ a file of named
+\emph on
+<source filename>.dumpraw
+\emph default
+ just after the intermediate code has been generated for a function, i.e.
+ before any optimizations are done.
+ The basic blocks
+\begin_inset LatexCommand \index{Basic blocks}
+
+\end_inset
+
+ at this stage ordered in the depth first number, so they may not be in
+ sequence of execution.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpgcse
+\begin_inset LatexCommand \index{-\/-dumpgcse}
+
+\end_inset
+
+
+\series default
+ Will create a dump of iCode's, after global subexpression elimination
+\begin_inset LatexCommand \index{Global subexpression elimination}
+
+\end_inset
+
+, into a file named
+\emph on
+<source filename>.dumpgcse.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpdeadcode
+\begin_inset LatexCommand \index{-\/-dumpdeadcode}
+
+\end_inset
+
+
+\series default
+ Will create a dump of iCode's, after deadcode elimination
+\begin_inset LatexCommand \index{Dead-code elimination}
+
+\end_inset
+
+, into a file named
+\emph on
+<source filename>.dumpdeadcode.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumploop
+\begin_inset LatexCommand \index{-\/-dumploop}
+
+\end_inset
+
+
+\series default
+\size large
+
+\size default
+Will create a dump of iCode's, after loop optimizations
+\begin_inset LatexCommand \index{Loop optimization}
+
+\end_inset
+
+, into a file named
+\emph on
+<source filename>.dumploop.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumprange
+\begin_inset LatexCommand \index{-\/-dumprange}
+
+\end_inset
+
+
+\series default
+\size large
+
+\size default
+Will create a dump of iCode's, after live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
+
+\end_inset
+
+, into a file named
+\emph on
+<source filename>.dumprange.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumlrange
+\begin_inset LatexCommand \index{-\/-dumlrange}
+
+\end_inset
+
+
+\series default
+ Will dump the life ranges
+\begin_inset LatexCommand \index{Live range analysis}
+
+\end_inset
+
+ for all symbols.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpregassign
+\begin_inset LatexCommand \index{-\/-dumpregassign}
+
+\end_inset
+
+
+\bar under
+
+\series default
+\bar default
+Will create a dump of iCode's, after register assignment
+\begin_inset LatexCommand \index{Register assignment}
+
+\end_inset
+
+, into a file named
+\emph on
+<source filename>.dumprassgn.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumplrange
+\begin_inset LatexCommand \index{-\/-dumplrange}
+
+\end_inset
+
+
+\series default
+ Will create a dump of the live ranges of iTemp's
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpall
+\begin_inset LatexCommand \index{-\/-dumpall}
+
+\end_inset
+
+
+\size large
+\bar under
+
+\series default
+\size default
+\bar default
+Will cause all the above mentioned dumps to be created.
+\layout Subsection
+
+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
+SDCC_LEAVE_SIGNALS
+\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
+
+\end_inset
+
+
+\series default
+ SDCC installs a signal handler
+\begin_inset LatexCommand \index{signal handler}
+
+\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.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+TMP
+\begin_inset LatexCommand \index{TMP}
+
+\end_inset
+
+,\SpecialChar ~
+TEMP
+\begin_inset LatexCommand \index{TEMP}
+
+\end_inset
+
+,\SpecialChar ~
+TMPDIR
+\begin_inset LatexCommand \index{TMPDIR}
+
+\end_inset
+
+
+\series default
+ Path, where temporary files will be created.
+ The order of the variables is the search order.
+ In a standard *nix environment these variables are not set, and there's
+ no need to set them.
+ On Windows it's recommended to set one of them.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+SDCC_HOME
+\begin_inset LatexCommand \index{SDCC\_HOME}
+
+\end_inset
+
+
+\series default
+ Path, see
+\begin_inset Quotes sld
+\end_inset
+
+2.3 Install and search paths
+\begin_inset Quotes srd
+\end_inset
+
+.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+SDCC_INCLUDE
+\begin_inset LatexCommand \index{SDCC\_INCLUDE}
+
+\end_inset
+
+
+\series default
+ Path, see
+\begin_inset Quotes sld
+\end_inset
+
+2.3 Install and search paths
+\begin_inset Quotes srd
+\end_inset
+
+.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+SDCC_LIB
+\begin_inset LatexCommand \index{SDCC\_LIB}
+
+\end_inset
+
+
+\series default
+ Path, see
+\begin_inset Quotes sld
+\end_inset
+
+2.3 Install and 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 documented.
+\layout Subsection
+
+MCS51/DS390 Storage Class
+\begin_inset LatexCommand \index{Storage class}
+
+\end_inset
+
+ Language Extensions
+\layout Standard
+
+In addition to the ANSI storage classes SDCC allows the following MCS51
+ specific storage classes.
+\layout Subsubsection
+
+xdata
+\begin_inset LatexCommand \index{xdata}
+
+\end_inset
+
+
+\layout Standard
+
+Variables declared with this storage class will be placed in the external
+ RAM.
+ This is the
+\series bold
+default
+\series default
+ storage class for Large Memory model, e.g.:
+\layout Verse
+
+
+\family typewriter
+xdata unsigned char xduc;
+\layout Subsubsection
+
+data
+\begin_inset LatexCommand \index{data}
+
+\end_inset
+
+
+\layout Standard
+
+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 directly
+ addressable portion of the internal RAM of a 8051, e.g.:
+\layout Verse
+
+
+\family typewriter
+data int iramdata;
+\layout Subsubsection
+
+idata
+\begin_inset LatexCommand \index{idata}
+
+\end_inset
+
+
+\layout Standard
+
+Variables declared with this storage class will be allocated into the indirectly
+ addressable portion of the internal ram of a 8051, e.g.:
+\layout Verse
+
+
+\family typewriter
+idata int idi;
+\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 iFlag;
+\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 special function registers and special bit variables of a 8051, eg:
+\layout Verse
+
+
+\family typewriter
+sfr at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 0x80 P0; /* 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 Subsection
+
+Pointers
+\begin_inset LatexCommand \index{Pointers}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC allows (via language extensions) pointers to explicitly point to any
+ of the memory spaces
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+ of the 8051.
+ In addition to the explicit pointers, the compiler uses (by default) generic
+ pointers which can be used to point to any of the memory spaces.
+\newline
+
+\newline
+Pointer declaration examples:
+\layout Verse
+
+
+\family typewriter
+/* pointer physically in xternal ram pointing to object in internal ram
+ */
+\newline
+data unsigned char * xdata p;
+\newline
+
+\newline
+/* pointer physically in code rom pointing to data in xdata space */
+\newline
+xdata unsigned char * code p;
+\newline
+
+\newline
+/* pointer physically in code space pointing to data in code space */
+\newline
+code unsigned char * code p;
+\newline
+
+\newline
+/* the following is a generic pointer physically located in xdata space
+ */
+\newline
+char * xdata p;
+\layout Standard
+
+Well you get the idea.
+
+\newline
+
+\newline
+All unqualified pointers are treated as 3-byte (4-byte for the ds390)
+\emph on
+generic
+\emph default
+ pointers.
+
+\size small
+
+\newline
+
+\newline
+
+\size default
+The highest order byte of the
+\emph on
+generic
+\emph default
+ pointers contains the data space information.
+ Assembler support routines are called whenever data is stored or retrieved
+ using
+\emph on
+generic
+\emph default
+ pointers.
+ These are useful for developing reusable library
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+ routines.
+ Explicitly specifying the pointer type will generate the most efficient
+ code.
+\layout Subsection
+
+Parameters
+\begin_inset LatexCommand \index{Parameters}
+
+\end_inset
+
+ & Local Variables
+\begin_inset LatexCommand \index{Local variable}
+
+\end_inset
+
+
+\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}
+
+\end_inset
+
+
+\emph default
+ so by default functions are non-reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+.
+\newline
+
+\newline
+They can be placed on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ either by using 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 or by using the
+\emph on
+reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+
+\emph default
+ keyword in the function declaration, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned char foo(char i) reentrant
+\newline
+{
+\newline
+...
+
+\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
+
+\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
+does not
+\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}
+
+\end_inset
+
+ addresses, e.g.:
+\layout Verse
+
+
+\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 unsigned char j;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\layout Standard
+
+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
+\emph on
+ j
+\emph default
+ in internal ram.
+ When compiled with
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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 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
+
+Overlaying
+\begin_inset LatexCommand \index{Overlaying}
+
+\end_inset
+
+
+\layout Standard
+
+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 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}
+
+\end_inset
+
+ is small.
+
+\emph default
+ If an explicit storage class
+\begin_inset LatexCommand \index{Storage class}
+
+\end_inset
+
+ is specified for a local variable, it will NOT be overlayed.
+\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}
+
+\end_inset
+
+ if they are not reentrant.
+\layout Standard
+
+Also note that the compiler does not do any processing of inline
+\begin_inset LatexCommand \index{inline}
+
+\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.
+\layout Standard
+
+Parameters and Local variables of functions that contain 16 or 32 bit multiplica
+tion
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ or division
+\begin_inset LatexCommand \index{Division}
+
+\end_inset
+
+ will NOT be overlayed since these are implemented using external functions,
+ e.g.:
+\layout Verse
+
+
+\family typewriter
+#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 ~
+P3 = errcd;
+\newline
+}
+\newline
+#pragma RESTORE
+\newline
+
+\newline
+void some_isr () interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ 2 using
+\begin_inset LatexCommand \index{using}
+
+\end_inset
+
+ 1
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+set_error(10);
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
+\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 ISR.
+ The #pragma\SpecialChar ~
+NOOVERLAY ensures that the parameters and local variables for
+ the function are NOT overlayed.
+\layout Subsection
+
+Interrupt Service Routines
+\layout Standard
+
+SDCC allows interrupt service routines to be coded in C, with some extended
+ keywords.
+\layout Verse
+
+
+\family typewriter
+void timer_isr (void) interrupt 1 using 1
+\newline
+{
+\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.
+ 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.
+ 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}
+
+\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.
+ If the interrupt service routines changes variables which are accessed
+ by other functions these variables should be declared
+\emph on
+volatile
+\emph default
+
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+.
+
+\layout Standard
+
+A special note here, int (16 bit) and long (32 bit) integer division
+\begin_inset LatexCommand \index{Division}
+
+\end_inset
+
+, multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ & modulus
+\begin_inset LatexCommand \index{Modulus}
+
+\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
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
+\emph default
+ option and the source file will need to be compiled using the
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-int-long-ren
+\emph default
+t
+\begin_inset LatexCommand \index{-\/-int-long-rent}
+
+\end_inset
+
+ compiler option.
+\layout Standard
+
+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
+.
+\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
+
+\layout Standard
+\align center
+
+\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
+
+\layout Standard
+
+Interrupt #
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="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
+
+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
+
+0
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+External 0
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+0x0003
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+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">
+<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
+
+\layout Standard
+
+0x0023
+\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
+
+5
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Timer 2 (8052)
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+0x002B
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\layout Standard
+
+If the interrupt service routine is defined without
+\emph on
+using
+\begin_inset LatexCommand \index{using}
+
+\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
+\layout Standard
+
+
+\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.
+\layout Verse
+
+
+\family typewriter
+int foo () critical
+\newline
+{
+\newline
+...
+
+\newline
+...
+
+\newline
+}
+\layout Standard
+
+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:
+\layout Verse
+
+
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+ data unsigned char counter;
+\newline
+void simpleInterrupt(void) interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ 1
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+counter++;
+\newline
+}
+\newline
+
+\newline
+void nakedInterrupt(void) interrupt 2 _naked
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter
+\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}
+
+\end_inset
+
+;
+\newline
+}
+\layout Standard
+
+For an 8051 target, the generated simpleInterrupt looks like:
+\layout Verse
+
+
+\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 ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\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
+
+whereas nakedInterrupt looks like:
+\layout Verse
+
+
+\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.
+\layout Standard
+
+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
+
+Functions using private banks
+\begin_inset LatexCommand \index{bank}
+
+\end_inset
+
+
+\layout Standard
+
+The
+\emph on
+using
+\begin_inset LatexCommand \index{using}
+
+\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}
+
+\end_inset
+
+
+\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
+
+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
+
+\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
+
+ 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
+
+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
+
+
+\layout Standard
+
+Data items can be assigned an absolute address with the
+\emph on
+at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ <address>
+\emph default
+ keyword, in addition to a storage class, e.g.:
+\layout Verse
+
+
+\family typewriter
+xdata
+\begin_inset LatexCommand \index{xdata}
+
+\end_inset
+
+ at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 0x7ffe unsigned int chksum;
+\layout Standard
+
+In the above example the variable chksum will located at 0x7ffe and 0x7fff
+ of the external ram.
+ 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
+
+) and the linker output files (.rst
+\begin_inset LatexCommand \index{.rst}
+
+\end_inset
+
+) and (.map
+\begin_inset LatexCommand \index{.map}
+
+\end_inset
+
+) are good places to look for such overlaps.
+\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
+
+
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+ xdata
+\begin_inset LatexCommand \index{xdata}
+
+\end_inset
+
+ at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 0x8000 unsigned char PORTA_8255;
+\layout Standard
+
+Absolute address can be specified for variables in all storage classes,
+ e.g.:
+\layout Verse
+
+
+\family typewriter
+bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+ at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 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 you routine using
+\layout Verse
+
+
+\family typewriter
+extern bit SDI;
+\newline
+extern bit SCLK;
+\newline
+extern bit CPOL;
+\newline
+
+\newline
+void DS1306_put(unsigned char value)
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+unsigned char mask=0x80;
+\newline
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+while(mask)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDI=(value & mask)?1:0;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SCLK=!CPOL;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SCLK=CPOL;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mask/=2;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+}
+\newline
+}
+\layout Standard
+
+Then, someplace in the code for the first hardware you would use
+\layout Verse
+
+
+\family typewriter
+bit at 0x80 SDI;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/*I/O port 0, bit 0*/
+\newline
+bit at 0x81 SCLK;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/*I/O port 0, bit 1*/
+\newline
+bit CPOL;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\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 ~
+/*I/O port 0, bit 3*/
+\newline
+bit at 0x91 SCLK;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/*I/O port 1, bit 1*/
+\newline
+bit CPOL;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/*This is a variable, let the linker allocate this one*/
+\layout Standard
+
+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 Subsection
+
+Startup Code
+\begin_inset LatexCommand \index{Startup code}
+
+\end_inset
+
+
+\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
+
+
+\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}
+
+\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
+
+Inline Assembler Code
+\begin_inset LatexCommand \index{Assembler routines}
+
+\end_inset
+
+
+\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
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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
+
+.
+ This 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
+ carefully before using this option.
+\layout Verse
+
+
+\family typewriter
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+
+\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
+
+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.
+
+\newline
+
+\newline
+Inline assembler code cannot reference any C-Labels, however it can reference
+ labels
+\begin_inset LatexCommand \index{Labels}
+
+\end_inset
+
+ defined by the inline assembler, e.g.:
+\layout Verse
+
+
+\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 ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+$0003: ;label (can be reference by inline assembler only)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm ;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some more c code */
+\newline
+}
+\layout Standard
+
+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, ie.
+ labels defines in inline assembly CANNOT be accessed by C statements.
+\layout Subsection
+
+int (16 bit)
+\begin_inset LatexCommand \index{int (16 bit)}
+
+\end_inset
+
+ and long (32 bit)
+\begin_inset LatexCommand \index{long (32 bit)}
+
+\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 routine, 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
+
+\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
+
+16 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
+
+_divsint.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 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-rent
+\begin_inset LatexCommand \index{-\/-int-long-rent}
+
+\end_inset
+
+
+\emph default
+ option.
+ Notice that you don't have to call this routines directly.
+ The compiler will use them automatically every time a integer operation
+ is required.
+\layout Subsection
+
+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 consists
+ 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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fsadd.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
+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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fssub.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
+subtract 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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fsdiv.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
+divide 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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fsmul.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
+multiply 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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2uchar.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 floating point to unsigned char
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2char.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 floating point to signed char
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2uint.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 floating point to unsigned int
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2int.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 floating point to signed int
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2ulong.
+\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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+convert floating point to unsigned long
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2long.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 floating point to signed long
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_uchar2fs.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 unsigned char to floating point
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_char2fs.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 char to floating point number
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_uint2fs.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 unsigned int to floating point
+\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
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_int2fs.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 int to 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
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\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
+\emph off
+\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
+
+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.
+ 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 Subsection
+
+MCS51 Memory Models
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{MCS51 memory}
+
+\end_inset
+
+
+\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 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 strongly recommended that the small model
+ be used unless absolutely required.
+\layout Subsection
+
+DS390 Memory Models
+\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 (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
+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)}
+
+\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 Subsection
+
+Defines Created by the Compiler
+\begin_inset LatexCommand \index{Defines created by the compiler}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler creates the following #defines
+\begin_inset LatexCommand \index{\#defines}
+
+\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
+
+ or __ds390
+\begin_inset LatexCommand \index{\_\_ds390}
+
+\end_inset
+
+ or __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
+
+
+\newline
+
+\layout Subsection
+
+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
+
+.
+ To force all messages to
+\begin_inset Quotes sld
+\end_inset
+
+standard output
+\begin_inset Quotes srd
+\end_inset
+
+ use
+\series bold
+-
+\series default
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+\emph default
+-
+\series default
+use-stdout
+\begin_inset LatexCommand \index{-\/-use-stdout}
+
+\end_inset
+
+.
+ Aditionaly, 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
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-reti\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-; MUST explicitly include ret in _naked function.
+
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_endasm;
+
+\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
+\pagebreak_top
+SDCC Technical Data
+\layout Subsection
+
+Optimizations
+\begin_inset LatexCommand \index{Optimizations}
+
+\end_inset
+
+
+\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}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler does local and global common subexpression elimination, e.g.:
+
+\layout Verse
+
+
+\family typewriter
+i = x + y + 1;
\newline
-}
-\family default
+j = x + y;
+\layout Standard
+
+will be translated to
+\layout Verse
+
+
+\family typewriter
+iTemp = x + y
+\newline
+i = iTemp + 1
+\newline
+j = iTemp
+\layout Standard
+
+Some subexpressions are not as obvious as the above example, e.g.:
+\layout Verse
+
+
+\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
+iTemp.c = 10;
+\newline
+iTemp.d = 11;
+\layout Standard
+
+The compiler will try to keep these temporary variables in registers.
+\layout Subsubsection
+
+Dead-Code Elimination
+\begin_inset LatexCommand \index{Dead-code elimination}
+
+\end_inset
+
-\newline
-For an 8051 target, the generated simpleInterrupt looks like:
-\newline
+\layout Verse
-\newline
\family typewriter
-_simpleIterrupt:
+int global;
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-acc
+void f () {
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b
+int i;
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dpl
+i = 1; \SpecialChar ~
+/* dead store */
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dph
+global = 1;\SpecialChar ~
+/* dead store */
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw
+global = 2;
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw,#0x00
+return;
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
+global = 3;\SpecialChar ~
+/* unreachable */
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int global; void f ()
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-pop\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw
+global = 2;
\newline
\SpecialChar ~
\SpecialChar ~
+return;
+\newline
+}
+\layout Subsubsection
+
+Copy-Propagation
+\begin_inset LatexCommand \index{Copy propagation}
+
+\end_inset
+
+
+\layout Verse
+
+
+\family typewriter
+int f() {
+\newline
\SpecialChar ~
\SpecialChar ~
-pop\SpecialChar ~
+int i, j;
+\newline
\SpecialChar ~
\SpecialChar ~
+i = 10;
+\newline
\SpecialChar ~
\SpecialChar ~
-dph
+j = i;
\newline
\SpecialChar ~
\SpecialChar ~
+return j;
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int f() {
+\newline
\SpecialChar ~
\SpecialChar ~
-pop\SpecialChar ~
+int i, j;
+\newline
\SpecialChar ~
\SpecialChar ~
+i = 10;
+\newline
\SpecialChar ~
\SpecialChar ~
-dpl
+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 Subsubsection
+
+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 ~
-pop\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 ~
+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 ~
-b
+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 ~
-pop\SpecialChar ~
+ar[itemp1] = itemp2;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-acc
+itemp1 += 5;
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-reti
-\family default
-
+itemp2 += 3;
\newline
+}
+\layout Standard
+
+The more expensive multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ is changed to a less expensive addition.
+\layout Subsubsection
+
+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
-\newline
-whereas nakedInterrupt looks like:
+The 'for' loop is of the form
\newline
\newline
\family typewriter
-_nakedInterrupt:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
+for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
+ += 1])
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-reti\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-; MUST explicitly include ret(i) in _naked function.
-\family default
-
-\newline
-
-\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
+<for body>
+\layout Itemize
-Functions using private banks
-\layout Standard
+The <for body> does not contain
+\begin_inset Quotes eld
+\end_inset
-The
-\emph on
-using
-\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
-\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
+continue
+\begin_inset Quotes erd
+\end_inset
-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 true
+ or 'break
+\begin_inset Quotes erd
+\end_inset
-\layout Standard
+.
+\layout Itemize
-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
+All goto's are contained within the loop.
+\layout Itemize
-).
-\newline
+No function calls within the loop.
+\layout Itemize
-\emph on
-(pending: I don't think this has been done yet)
-\layout Standard
+The loop control variable <sym> is not assigned any value within the loop
+\layout Itemize
-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 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
+The loop control variable does NOT participate in any arithmetic operation
+ within the loop.
+\layout Itemize
-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
+There are NO switch statements in the loop.
+\layout Subsubsection
-Absolute Addressing
+Algebraic Simplifications
\layout Standard
-Data items can be assigned an absolute address with the
-\emph on
-at <address>
-\emph default
- keyword, in addition to a storage class, e.g.:
-\newline
+SDCC does numerous algebraic simplifications, the following is a small sub-set
+ of these optimizations.
+\layout Verse
-\newline
\family typewriter
-xdata at 0x8000 unsigned char PORTA_8255 ;
+i = j + 0 ; /* changed to */ i = j;
\newline
-
-\family default
-
+i /= 2; /* changed to */ i >>= 1;
\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
-\emph on
-memory mapped
-\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) and the linker output files (.rst) and
- (.map) are a good places to look for such overlaps.
+i = j - j ; /* changed to */ i = 0;
\newline
+i = j / 1 ; /* changed to */ i = j;
+\layout Standard
-\newline
-Absolute address can be specified for variables in all storage classes,
- e.g.:
-\newline
+Note the subexpressions
+\begin_inset LatexCommand \index{Subexpression}
-\newline
+\end_inset
-\family typewriter
-bit at 0x02 bvar;
-\newline
+ given above are generally introduced by macro expansions or as a result
+ of copy/constant propagation.
+\layout Subsubsection
-\newline
+'switch' Statements
+\begin_inset LatexCommand \index{switch statement}
+
+\end_inset
-\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
-Startup Code
\layout Standard
-The compiler inserts a call to the C routine
-\emph on
-_sdcc_external_startup()
-\series bold
-\emph default
-
-\series default
-at the start of the CODE area.
- This routine is in the runtime library.
- 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
+SDCC changes switch statements to jump tables
+\begin_inset LatexCommand \index{jump tables}
-Inline Assembler Code
-\layout Standard
+\end_inset
-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
----peep-asm
-\emph default
- command line option is used, the inline assembler code will be passed through
- the peephole optimizer.
- 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
+ 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
-\newline
\family typewriter
-_asm
+switch(i) {\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 ~
+switch (i) {
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 4: ...\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 ;
-\family default
-\size small
-
-\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.
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+case 1: ...
\newline
-
-\newline
-Inline assembler code cannot reference any C-Labels, however it can reference
- labels defined by the inline assembler, e.g.:
-\newline
-
-\newline
-
-\family typewriter
-foo() {
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 5: ...\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 */
+case 2: ...
+
\newline
-clabel:\SpecialChar ~
\SpecialChar ~
-/* inline assembler cannot reference this label */
-\newline
\SpecialChar ~
\SpecialChar ~
+case 3: ...\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-$0003: ;label (can be reference by inline assembler only)
-\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_endasm ;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+case 6: ...\SpecialChar ~
\SpecialChar ~
-/* some more c code */
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\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 ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
}
-\newline
-
-\newline
-
-\family default
-In other words inline assembly code can access labels defined in inline
- assembly within the scope of the funtion.
-
-\layout Standard
-
-The same goes the other way, ie.
- labels defines in inline assembly CANNOT be accessed by C statements.
-\layout Subsection
-
-int (16 bit) and long (32 bit) 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
-
-\newline
-
-\emph on
-<pending: tabularise this>
-\emph default
-
-\newline
-
-\newline
-_mulsint.c - signed 16 bit multiplication (calls _muluint)
-\newline
-_muluint.c - unsigned 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
-_mulslong.c - signed 32 bit multiplication (calls _mululong)
-\newline
-_mululong.c - unsigned32 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
-
-\newline
-
-\newline
+Both the above switch statements will be implemented using a jump-table.
+\end_deeper
+\layout Itemize
-\size default
-Since they are compiled as
-\emph on
-non-reentrant
-\emph default
-, interrupt 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
----stack-auto
-\emph default
- option, after which the source program will have to be compiled with
-\emph on
----int-long-rent
-\emph default
- option.
-\layout Subsection
+The number of case labels is at least three, since it takes two conditional
+ statements to handle the boundary conditions.
+\layout Itemize
-Floating Point Support
+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
-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
+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
-\newline
+\family typewriter
+switch (i) {
\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
+\SpecialChar ~
+\SpecialChar ~
+case 1: ...
+
\newline
-_char2fs.c - convert char to floating point number
+\SpecialChar ~
+\SpecialChar ~
+case 2: ...
+
\newline
-_uint2fs.c - convert unsigned int to floating point
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...
+
\newline
-_int2fs.c - convert int to floating point numbers
+\SpecialChar ~
+\SpecialChar ~
+case 4: ...
+
\newline
-_ulong2fs.c - convert unsigned long to floating point number
+\SpecialChar ~
+\SpecialChar ~
+case 9: ...
+
\newline
-_long2fs.c - convert long to floating point number
-\size footnotesize
-
+\SpecialChar ~
+\SpecialChar ~
+case 10: ...
+
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+case 11: ...
+
\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
-\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.
+\SpecialChar ~
+\SpecialChar ~
+case 12: ...
+\newline
+}
\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 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 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
+If the above switch statement is broken down into two switch statements
+\layout Verse
-DS390 Memory Models
-\layout Standard
-The only model supported is Flat 24.
- 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.
+\family typewriter
+switch (i) {
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+case 1: ...
+
\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.
+\SpecialChar ~
+\SpecialChar ~
+case 2: ...
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...
+
\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
-, the boot loader or similar code must ensure that the processor is in 24
- bit contiguous addressing mode before calling the SDCC startup code.
+\SpecialChar ~
+\SpecialChar ~
+case 4: ...
+
\newline
+}
+\layout Standard
+
+and
+\layout Verse
+
+\family typewriter
+switch (i) {
\newline
-Like the
-\emph on
----model-large
-\emph default
- option, variables will by default be placed into the XDATA segment.
+\SpecialChar ~
+\SpecialChar ~
+case 9: \SpecialChar ~
+...
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+case 10: ...
+
\newline
-Segments may be placed anywhere in the 4 meg address space using the usual
- ---*-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
+\SpecialChar ~
+\SpecialChar ~
+case 11: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 12:\SpecialChar ~
+...
+
+\newline
+}
\layout Standard
-The compiler creates the following #defines.
-\layout Itemize
-
-SDCC - this Symbol is always defined.
-\layout Itemize
-
-SDCC_mcs51 or SDCC_ds390 or SDCC_z80, etc - depending on the model used
- (e.g.: -mds390)
-\layout Itemize
-
-__mcs51 or __ds390 or __z80, etc - depending on the model used (e.g.
- -mz80)
-\layout Itemize
-
-SDCC_STACK_AUTO - this symbol is defined when
-\emph on
----stack-auto
-\emph default
- option is used.
-\layout Itemize
+then both the switch statements will be implemented using jump-tables whereas
+ the unmodified switch statement will not be.
+ The pragma NOJTBOUND
+\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
-SDCC_MODEL_SMALL - when
-\emph on
----model-small
-\emph default
- is used.
-\layout Itemize
+\end_inset
-SDCC_MODEL_LARGE - when
+ can be used to turn off checking the
\emph on
----model-large
+j
\emph default
- is used.
-\layout Itemize
-
-SDCC_USE_XSTACK - when
+ump
\emph on
----xstack
+t
\emph default
- option is used.
-\layout Itemize
-
-SDCC_STACK_TENBIT - when
+able
\emph on
--mds390
+bound
\emph default
- is used
-\layout Itemize
+aries.
+\layout Subsubsection
-SDCC_MODEL_FLAT24 - when
-\emph on
--mds390
-\emph default
- is used
-\layout Section
+Bit-shifting Operations
+\begin_inset LatexCommand \index{Bit shifting}
-SDCC Technical Data
-\layout Subsection
+\end_inset
-Optimizations
+.
\layout Standard
-SDCC performs a host of standard optimizations in addition to some MCU specific
- optimizations.
-
-\layout Subsubsection
+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
-Sub-expression Elimination
-\layout Standard
-The compiler does local and global common subexpression elimination, e.g.:
+\family typewriter
+unsigned char i;
+\newline
+...
\newline
-
+i>>= 4;
\newline
+...
+\layout Standard
-\family typewriter
-i = x + y + 1;
-\newline
-j = x + y;
-\family default
+generates the following code:
+\layout Verse
-\newline
+\family typewriter
+mov a,_i
\newline
-will be translated to
+swap a
\newline
-
+anl a,#0x0f
\newline
+mov _i,a
+\layout Standard
+
+In general SDCC will never setup a loop if the shift count is known.
+ Another example:
+\layout Verse
+
\family typewriter
-iTemp = x + y
+unsigned int i;
\newline
-i = iTemp + 1
+...
+
\newline
-j = iTemp
+i >>= 9;
\newline
+...
+\layout Standard
-\family default
+will generate:
+\layout Verse
+
+\family typewriter
+mov a,(_i + 1)
\newline
-Some subexpressions are not as obvious as the above example, e.g.:
+mov (_i + 1),#0x00
\newline
-
+clr c
+\newline
+rrc a
\newline
+mov _i,a
+\layout Standard
+
+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:
+\layout Verse
+
\family typewriter
-a->b[i].c = 10;
+unsigned char i;
+\newline
+...
+
\newline
-a->b[i].d = 11;
+i = ((i << 1) | (i >> 7));
\family default
\newline
-\newline
-In this case the address arithmetic a->b[i] will be computed only once;
- the equivalent code in C would be.
-\newline
+\family typewriter
+...
+\layout Standard
+
+will generate the following code:
+\layout Verse
-\newline
\family typewriter
-iTemp = a->b[i];
+mov a,_i
\newline
-iTemp.c = 10;
+rl a
\newline
-iTemp.d = 11;
-\family default
+mov _i,a
+\layout Standard
-\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.:
+\layout Verse
-\newline
-The compiler will try to keep these temporary variables in registers.
+
+\family typewriter
+i = ((i >> 7) | (i << 1)); /* left-bit rotation */
\layout Subsubsection
-Dead-Code Elimination
+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
-int global;
-\newline
-void f () {
+unsigned int gint;
\newline
-\SpecialChar ~
-\SpecialChar ~
-int i;
+
\newline
-\SpecialChar ~
-\SpecialChar ~
-i = 1; \SpecialChar ~
-/* dead store */
+foo () {
\newline
-\SpecialChar ~
-\SpecialChar ~
-global = 1;\SpecialChar ~
-/* dead store */
+unsigned char hob;
\newline
\SpecialChar ~
\SpecialChar ~
-global = 2;
+...
+
\newline
\SpecialChar ~
\SpecialChar ~
-return;
+hob = (gint >> 15) & 1;
\newline
\SpecialChar ~
\SpecialChar ~
-global = 3;\SpecialChar ~
-/* unreachable */
+..
+
\newline
}
-\family default
-
-\newline
+\layout Standard
-\newline
-will be changed to
-\newline
+will generate the following code:
+\layout Verse
-\newline
\family typewriter
-int global; void f ()
-\newline
-{
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 2;
-\newline
\SpecialChar ~
\SpecialChar ~
-return;
-\newline
-}
-\layout Subsubsection
-
-Copy-Propagation
-\layout Standard
-
-
-\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
-
-\newline
-
-\newline
-will be changed to
-\newline
-
-\newline
-
-\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
-}
-\newline
-
-\newline
-
-\family default
-Note: the dead stores created by this copy propagation will be eliminated
- by dead-code elimination.
-\layout Subsubsection
-
-Loop Optimizations
-\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, loop induction optimizati
-on causes an increase in register pressure, which may cause unwanted spilling
- of other temporary variables into the stack / 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 ---noinduction
- option) or for a given function only using #pragma\SpecialChar ~
-NOINDUCTION.
-\newline
-
-\newline
-Loop Invariant:
-\newline
-
-\newline
-
-\family typewriter
-for (i = 0 ; i < 100 ; i ++)
-\newline
- \SpecialChar ~
- \SpecialChar ~
-f += k + l;
-\family default
-
-\newline
-
-\newline
-changed to
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ 61 ;\SpecialChar ~
+ hob.c 7
\newline
-
+000A E5*01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ 62\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ mov\SpecialChar ~
+\SpecialChar ~
+ a,(_gint + 1)
\newline
-
-\family typewriter
-itemp = k + l;
+000C 23\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ 63\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ rl\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ a
\newline
-for (i = 0; i < 100; i++)
+000D 54 01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ 64\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ andl\SpecialChar ~
+ a,#0x01
\newline
+000F F5*02\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-f += itemp;
-\family default
-
-\newline
-
-\newline
-As mentioned previously some loop invariants are not as apparent, all static
- address computations are also moved out of the loop.
-\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ 65\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ mov\SpecialChar ~
+\SpecialChar ~
+ _foo_hob_1_1,a
+\layout Standard
-\newline
-Strength Reduction, this optimization substitutes an expression by a cheaper
- expression:
-\newline
+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
-\newline
\family typewriter
-for (i=0;i < 100; i++)
-\newline
-\SpecialChar ~
-\SpecialChar ~
-ar[i*5] = i*3;
-\family default
+xyz = gint + ((gint >> 15) & 1);
+\layout Standard
-\newline
+will still be recognized.
+\layout Subsubsection
-\newline
-changed to
-\newline
+Peephole Optimizer
+\begin_inset LatexCommand \index{Peephole optimizer}
-\newline
+\end_inset
-\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
-\newline
+\layout Standard
-\newline
-The more expensive multiplication is changed to a less expensive addition.
-\layout Subsubsection
+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
-Loop Reversing
\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
+\backslash
+/
\end_inset
-decrement and jump if not zero
-\begin_inset Quotes erd
-\end_inset
+-peep-file
+\begin_inset LatexCommand \index{-\/-peep-file}
- 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
+\end_inset
-The 'for' loop is of the form
-\newline
+ <filename>
+\emph default
+ option.
+ The rule language is best illustrated with examples.
+\layout Verse
-\newline
\family typewriter
-for (<symbol> = <expression> ; <sym> [< | <=] <expression> ; [<sym>++ |
- <sym> += 1])
+replace {
\newline
\SpecialChar ~
\SpecialChar ~
+mov %1,a
+\newline
\SpecialChar ~
\SpecialChar ~
-<for body>
-\layout Itemize
-
-The <for body> does not contain
-\begin_inset Quotes eld
-\end_inset
+mov a,%1
+\newline
+} by {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+mov %1,a
+\newline
+}
+\layout Standard
-continue
-\begin_inset Quotes erd
-\end_inset
+The above rule will change the following assembly
+\begin_inset LatexCommand \index{Assembler routines}
- or 'break
-\begin_inset Quotes erd
\end_inset
-.
-\layout Itemize
-
-All goto's are contained within the loop.
-\layout Itemize
+ sequence:
+\layout Verse
-No function calls within the loop.
-\layout Itemize
-The loop control variable <sym> is not assigned any value within the loop
-\layout Itemize
+\family typewriter
+mov r1,a
+\newline
+mov a,r1
+\layout Standard
-The loop control variable does NOT participate in any arithmetic operation
- within the loop.
-\layout Itemize
+to
+\layout Verse
-There are NO switch statements in the loop.
-\layout Subsubsection
-Algebraic Simplifications
+\family typewriter
+mov r1,a
\layout Standard
-SDCC does numerous algebraic simplifications, the following is a small sub-set
- of these optimizations.
-\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:
+\layout Verse
-\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;
+mov r1,a
\newline
-i = j / 1 ; /* changed to */ i = j;
-\family default
+mov a,r2
+\layout Standard
+will remain unmodified.
\newline
\newline
-Note the subexpressions given above are generally introduced by macro expansions
- or as a result of copy/constant propagation.
-\layout Subsubsection
+Other special case optimizations may be added by the user (via
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-'switch' Statements
\layout Standard
-SDCC changes switch statements to jump tables when the following conditions
- are true.
-
-\layout Itemize
+\backslash
+/
+\end_inset
-The case labels are in numerical sequence, the labels need not be in order,
- and the starting number need not be one or zero.
+-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
+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
-\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: ...
-
+The syntax for a rule is as follows:
+\layout Verse
+
+
+\family typewriter
+rule := replace [ restart ] '{' <assembly sequence> '
+\backslash
+n'
\newline
-case 5:...
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-case 2: ...
-
+ '}' by '{' '
+\backslash
+n'
\newline
-case 3:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-case 3: ...
-
-\newline
-case 6:...
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-case 4: ...
-
+ <assembly sequence> '
+\backslash
+n'
\newline
-}\SpecialChar ~
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ '}' [if <functionName> ] '
+\backslash
+n'
+\layout Standard
+
+<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:
+\layout Verse
+
+
+\family typewriter
+replace restart {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+pop %1
+\newline
+\SpecialChar ~
+\SpecialChar ~
+push %1 } by {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+; nop
+\newline
+}
+\layout Standard
+
+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.:
+\layout Verse
+
+
+\family typewriter
+pop ar1
+\newline
+pop ar2
+\newline
+push ar2
+\newline
+push ar1
+\layout Standard
+
+would result in:
+\layout Verse
+
+
+\family typewriter
+pop ar1
+\newline
+; nop
+\newline
+push ar1
+\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:
+\layout Verse
+
+
+\family typewriter
+; nop
+\newline
+; nop
+\layout Standard
+
+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 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.
+ 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
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file option.
+\layout Subsection
+
+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 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.
+\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}
-\newline
+\end_inset
-\family default
-Both the above switch statements will be implemented using a jump-table.
+.
\layout Itemize
-The number of case labels is at least three, since it takes two conditional
- statements to handle the boundary conditions.
+NOIV
+\begin_inset LatexCommand \index{\#pragma NOIV}
+
+\end_inset
+
+ - 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
-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.
-
+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 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
-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
+\backslash
+/
+\end_inset
-\newline
+-callee-saves command line option is used, the function names specified
+ in #pragma\SpecialChar ~
+CALLEE-SAVES
+\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
-\family typewriter
-switch (i) {
-\newline
-case 1: ...
-
-\newline
-case 2: ...
-
-\newline
-case 3: ...
-
-\newline
-case 4: ...
-
-\newline
-case 9: ...
-
-\newline
-case 10: ...
-
-\newline
-case 11: ...
-
-\newline
-case 12: ...
-
-\newline
-}
-\family default
+\end_inset
-\newline
+ is appended to the list of functions specified in the command line.
+\layout Standard
-\newline
-If the above switch statement is broken down into two switch statements
-\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.
+\layout Verse
-\newline
\family typewriter
-switch (i) {
-\newline
-case 1: ...
-
-\newline
-case 2: ...
-
-\newline
-case 3: ...
-
-\newline
-case 4: ...
-
-\newline
-}
-\newline
+#pragma SAVE
+\begin_inset LatexCommand \index{\#pragma SAVE}
+
+\end_inset
+ /* save the current settings */
\newline
+#pragma NOGCSE
+\begin_inset LatexCommand \index{\#pragma NOGCSE}
-\family default
-and
-\family typewriter
+\end_inset
+ /* turnoff global subexpression elimination */
\newline
+#pragma NOINDUCTION
+\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+\end_inset
+
+ /* turn off induction optimizations */
\newline
-switch (i) {
+int foo ()
\newline
-case 9: \SpecialChar ~
-...
-
+{
\newline
-case 10: ...
+\SpecialChar ~
+ \SpecialChar ~
+ ...
\newline
-case 11: ...
-
+\SpecialChar ~
+ \SpecialChar ~
+ /* large code */
\newline
-case 12:\SpecialChar ~
-...
+\SpecialChar ~
+ \SpecialChar ~
+ ...
\newline
-}
-\newline
-
+}
\newline
+#pragma RESTORE
+\begin_inset LatexCommand \index{\#pragma RESTORE}
-\family default
-then both the switch statements will be implemented using jump-tables whereas
- the unmodified switch statement will not be.
-\layout Subsubsection
+\end_inset
-Bit-shifting Operations.
+ /* turn the optimizations back on */
\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
+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
-\newline
-unsigned char i;
-\newline
-...
+Library Routines
+\emph on
+ <pending: this is messy and incomplete>
+\emph default
-\newline
-i>>= 4;
-\newline
-...
-\newline
+\layout Enumerate
-\family default
+Compiler support routines (_gptrget, _mulint etc)
+\layout Enumerate
-\newline
-generates the following code:
-\newline
+Stdclib functions (puts, printf, strcat etc)
+\layout Enumerate
-\family typewriter
+Math functions (sin, pow, sqrt etc)
+\layout Comment
-\newline
-mov a,_i
-\newline
-swap a
-\newline
-anl a,#0x0f
-\newline
-mov _i,a
-\family default
+license statements for the libraries are missing
+\layout Subsection
-\newline
+Interfacing with Assembly Routines
+\begin_inset LatexCommand \index{Assembler routines}
-\newline
-In general SDCC will never setup a loop if the shift count is known.
- Another example:
-\newline
+\end_inset
-\newline
-\family typewriter
-unsigned int i;
-\newline
-...
+\layout Subsubsection
+
+Global Registers used for Parameter Passing
+\begin_inset LatexCommand \index{Parameter passing}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler always uses the global registers
+\emph on
+DPL, DPH
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
+
+\end_inset
+
+, B
+\begin_inset LatexCommand \index{B (register)}
+
+\end_inset
+
-\newline
-i >>= 9;
-\newline
-...
-\family default
+\emph default
+and
+\emph on
+ ACC
+\begin_inset LatexCommand \index{ACC}
-\newline
+\end_inset
-\newline
-will generate:
-\newline
-\newline
+\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
-mov a,(_i + 1)
-\newline
-mov (_i + 1),#0x00
-\newline
-clr c
-\newline
-rrc a
-\newline
-mov _i,a
-\family default
+\layout Standard
-\newline
+\backslash
+/
+\end_inset
-\newline
-Note that SDCC stores numbers in little-endian format (i.e.
- lowest order first).
+-stack-auto is used) or in the internal / external ram (depending on the
+ memory model).
+
\layout Subsubsection
-Bit-rotation
+Assembler Routine(non-reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+)
+\begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
+
+\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
+In the following example the function c_func calls an assembler routine
+ asm_func, which takes two parameters.
+\layout Verse
-\newline
\family typewriter
-unsigned char i;
-\newline
-...
-
-\newline
-i = ((i << 1) | (i >> 7));
-\family default
-
-\newline
-...
+extern int asm_func(unsigned char, unsigned char);
\newline
\newline
-will generate the following code:
+int c_func (unsigned char i, unsigned char j)
\newline
-
+{
\newline
-
-\family typewriter
-mov a,_i
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return asm_func(i,j);
\newline
-rl a
+}
\newline
-mov _i,a
-\family default
\newline
-
+int main()
\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.:
+{
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return c_func(10,9);
\newline
-
-\family typewriter
-i = ((i >> 7) | (i << 1)); /* left-bit rotation */
-\layout Subsubsection
-
-Highest Order Bit
+}
\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.:
-\newline
+The corresponding assembler function is:
+\layout Verse
-\newline
-
-\family typewriter
-unsigned int gint;
-\newline
-\newline
-foo () {
-\newline
-unsigned char hob;
+\family typewriter
+.globl _asm_func_PARM_2
\newline
\SpecialChar ~
\SpecialChar ~
-...
-
-\newline
\SpecialChar ~
\SpecialChar ~
-hob = (gint >> 15) & 1;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.globl _asm_func
\newline
\SpecialChar ~
\SpecialChar ~
-..
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area OSEG
\newline
-}
-\family default
-
+_asm_func_PARM_2:
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.ds 1
\newline
-will generate the following code:
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area CSEG
\newline
-
-\family typewriter
-
+_asm_func:
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov a,dpl
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+add a,_asm_func_PARM_2
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov dpl,a
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- 61 ;\SpecialChar ~
- hob.c 7
-\newline
\SpecialChar ~
\SpecialChar ~
- 000A E5*01\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
+
+\end_inset
+
+,#0x00
+\newline
+\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+ret
+\layout Standard
+
+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 variable name for the second parameter will be _<function_n
+ame>_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:
+\layout Verse
+
+
+\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 ~
- 62\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+return c_func(10,9);
+\newline
+}
+\layout Standard
+
+The corresponding assembler routine is:
+\layout Verse
+
+
+\family typewriter
+.globl _asm_func
+\newline
+_asm_func:
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- a,(_gint + 1)
+push _bp
\newline
\SpecialChar ~
\SpecialChar ~
- 000C 33\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 ~
+clr c
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+add a,#0xfd
+\newline
\SpecialChar ~
- 63\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov r0,a
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- rlc\SpecialChar ~
- a
+add a,#0xfc
\newline
\SpecialChar ~
\SpecialChar ~
- 000D E4\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 ~
- 64\SpecialChar ~
\SpecialChar ~
+mov dph,#0x00
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+mov sp,_bp
+\newline
\SpecialChar ~
\SpecialChar ~
- clr\SpecialChar ~
- a
-\newline
\SpecialChar ~
\SpecialChar ~
- 000E 13\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 Subsection
+
+External Stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{External stack}
+
+\end_inset
+
+
+\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
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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
+
+\backslash
+/
+\end_inset
+
+-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
+
+ANSI-Compliance
+\begin_inset LatexCommand \index{ANSI-compliance}
+
+\end_inset
+
+
+\layout Standard
+
+Deviations from the compliance:
+\layout Itemize
+
+functions are not always reentrant.
+\layout Itemize
+
+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
+
+
+\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 ~
- 65\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+struct s rets;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- rrc\SpecialChar ~
- a
+...
+
\newline
\SpecialChar ~
\SpecialChar ~
- 000F F5*02\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
+
+' (64 bit integers
+\begin_inset LatexCommand \index{int (64 bit) (not supported)}
+
+\end_inset
+
+) not supported.
+\layout Itemize
+
+'double
+\begin_inset LatexCommand \index{double (not supported)}
+
+\end_inset
+
+' precision floating point
+\begin_inset LatexCommand \index{Floating point support}
+
+\end_inset
+
+not supported.
+\layout Itemize
+
+No support for setjmp and longjmp (for now).
+\layout Itemize
+
+Old K&R style
+\begin_inset LatexCommand \index{K\&R style}
+
+\end_inset
+
+ function declarations are NOT allowed.
+\begin_deeper
+\layout Verse
+
+
+\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
+
+functions declared as pointers must be dereferenced during the call.
+\begin_deeper
+\layout Verse
+
+
+\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 Subsection
+
+Cyclomatic Complexity
+\begin_inset LatexCommand \index{Cyclomatic complexity}
+
+\end_inset
+
+
+\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
+
+\layout Standard
+
+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
+
+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
+
+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
+
+NEVER jump into a LOOP.
+\layout Itemize
+
+Declare the variables to be local 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 ~
+unsigned char ch1 = p1 % ch ;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+....
+\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 ~
- 66\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+unsigned char ch1 = (unsigned char)p1 % ch ;
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
- mov\SpecialChar ~
- _foo_hob_1_1,a
+....
\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 Subsection
+
+Notes on MCS51 memory
+\begin_inset LatexCommand \index{MCS51 memory}
+
+\end_inset
+ layout
+\layout Standard
+
+The 8051 family of microcontrollers have a minimum of 128 bytes of internal
+ RAM memory which is structured as follows
\newline
-\family default
-Variations of this case however will
+\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 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
-not
+idata
\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
+).
+ Furthermore, some chips may have some built in external memory (
+\emph on
+xdata
+\emph default
+) which should not be confused with the internal, directly addressable RAM
+ memory (
+\emph on
+data
+\emph default
+).
+ Usually 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).
+\layout Standard
-\newline
+Normally SDCC will only use the first bank
+\begin_inset LatexCommand \index{bank}
-\family typewriter
-xyz = gint + ((gint >> 15) & 1);
-\family default
+\end_inset
-\newline
+ 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}
-\newline
-will still be recognized.
-\layout Subsubsection
+\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
+ 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}
+
+\end_inset
+
+ 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
-Peep-hole Optimizer
\layout Standard
-The compiler uses a rule based, pattern matching and re-writing mechanism
- for peep-hole optimization.
- It is inspired by
+\backslash
+/
+\end_inset
+
+-data-loc
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+ to specify the start address of the
\emph on
-copt
+data
\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
+ and -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-iram-size to specify the size of the total internal RAM (
+\emph on
+data
+\emph default
++
\emph on
----peep-file <filename>
+idata
\emph default
- option.
- The rule language is best illustrated with examples.
-\newline
+).
+
+\layout Standard
-\newline
+By default the 8051 linker will place the stack after the last byte of data
+ variables.
+ Option -
+\begin_inset ERT
+status Collapsed
-\family typewriter
-replace {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov %1,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov a,%1
-\newline
-} by {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov %1,a
-\newline
-}
-\family default
+\layout Standard
-\newline
+\backslash
+/
+\end_inset
-\newline
-The above rule will change the following assembly sequence:
-\newline
+-stack-loc
+\begin_inset LatexCommand \index{-\/-stack-loc}
+
+\end_inset
+
+ 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
+idata
+\emph default
+) you can place the stack on it.
+ You may also need to use -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xdata-loc
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+ to set the start address of the external RAM (
+\emph on
+xdata
+\emph default
+) and -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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
+
+\backslash
+/
+\end_inset
+
+-code-loc
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+ and -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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
+
+The 8051 linker generates two files with memory allocation information.
+ The first, with extension .map shows all the variables and segments.
+ The second with extension .mem shows the final memory layout.
+ The linker will complaint 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
+
+Tools
+\begin_inset LatexCommand \index{Tools}
+
+\end_inset
+ included in the distribution
\newline
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-mov r1,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov a,r1
-\family default
+\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
+
+\layout Standard
+
+Simulator for various architectures
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\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
+
+\layout Standard
-\newline
+header file conversion
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-to
-\newline
+\layout Standard
-\newline
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-mov r1,a
-\family default
+\layout Standard
-\newline
+mh2h.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\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
+\layout Standard
-\newline
+header file conversion
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-mov r1,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov a,r2
-\family default
+\layout Standard
-\newline
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-will remain unmodified.
-\newline
+\layout Standard
-\newline
-Other special case optimizations may be added by the user (via
-\emph on
----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
+as-gbz80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\newline
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-replace { lcall %1 } by { acall %1 }
-\newline
-replace { ljmp %1 } by { ajmp %1 }
-\family default
+\layout Standard
-\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
+\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
-The syntax for a rule is as follows:
-\newline
+\layout Standard
-\newline
+as-z80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\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'
-\newline
+\layout Standard
-\family default
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-<assembly sequence> := assembly instruction (each instruction including
- labels must be on a separate line).
-\newline
+\layout Standard
-\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 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
-\family typewriter
-replace restart {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-pop %1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push %1 } by {
-\newline
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\newline
-}
-\family default
+\layout Standard
-\newline
+asx8051
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\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
+\layout Standard
-\newline
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-pop ar1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-pop ar2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar1
-\family default
+\layout Standard
-\newline
-\newline
-would result in:
-\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
+\layout Standard
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-pop ar1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar1
-\family default
+sdcdb
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\newline
+Simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\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
+\layout Standard
-\newline
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\newline
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\family default
+\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
+\layout Standard
-\newline
-A conditional function can be attached to a rule.
- Attaching rules are somewhat more involved, let me illustrate this with
- an example.
-\newline
+aslink
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\family typewriter
-replace {
-\newline
-\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-ljmp %5
-\newline
-%2:
-\newline
-} by {
-\newline
-\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-sjmp %5
-\newline
-%2:
-\newline
-} if labelInRange
-\family default
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\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
-\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.
- 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 ---peep-file option.
-\layout Subsection
-Pragmas
+\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
-SDCC supports the following #pragma directives.
-\layout Itemize
+link-z80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-SAVE - this will save all current options to the SAVE/RESTORE stack.
- See RESTORE.
-\layout Itemize
+\layout Standard
-RESTORE - 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
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-NOGCSE - will stop global subexpression elimination.
-\layout Itemize
+\layout Standard
-NOINDUCTION - will stop loop induction optimizations.
-\layout Itemize
-NOJTBOUND - will not generate code for boundary value checking, when switch
- statements are turned into jump-tables.
-\layout Itemize
+\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
-NOOVERLAY - the compiler will not overlay the parameters and local variables
- of a function.
-\layout Itemize
+\layout Standard
-LESS_PEDANTIC - the compiler will not warn you anymore for obvious mistakes,
- you'r on your own now ;-(
-\layout Itemize
+link-gbz80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-NOLOOPREVERSE - Will not do loop reversal optimization
-\layout Itemize
+\layout Standard
-EXCLUDE NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation
- of pair of push/pop instruction in ISR function (using interrupt 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.
-\layout Itemize
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-NOIV - 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
+\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" 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
-CALLEE-SAVES 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 ---callee-saves command line option is used, the function names specified
- in #pragma\SpecialChar ~
-CALLEE-SAVES is appended to the list of functions specified in
- the command line.
\layout Standard
-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
-\newline
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+</lyxtabular>
-\family typewriter
-#pragma SAVE /* save the current settings */
-\newline
-#pragma NOGCSE /* turnoff global subexpression elimination */
-\newline
-#pragma NOINDUCTION /* turn off induction optimizations */
-\newline
-int foo ()
-\newline
-{
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-\SpecialChar ~
- \SpecialChar ~
- /* large code */
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-}
-\newline
-#pragma RESTORE /* turn the optimizations back on */
-\family default
+\end_inset
-\newline
\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
+Related open source tools
+\begin_inset LatexCommand \index{Related tools}
-\emph on
-<pending: this is messy and incomplete>
-\emph default
- Library Routines
-\layout Enumerate
+\end_inset
-Compiler support routines (_gptrget, _mulint etc)
-\layout Enumerate
-Stdclib functions (puts, printf, strcat etc)
-\layout Enumerate
+\newline
-Math functions (sin, pow, sqrt etc)
-\layout Subsection
+\layout Standard
+\align center
-Interfacing with Assembly Routines
-\layout Subsubsection
+\begin_inset Tabular
+<lyxtabular version="3" rows="8" 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
-Global Registers used for Parameter Passing
\layout Standard
-The compiler always uses the global registers
-\emph on
-DPL,DPH,B
-\emph default
-and
-\emph on
- ACC
-\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 ---stack-auto is used) or in the internal / external ram
- (depending on the memory model).
-
-\layout Subsubsection
+Name
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-Assembler Routine(non-reentrant)
\layout Standard
-In the following example the function cfunc calls an assembler routine asm_func,
- which takes two parameters.
-\newline
+Purpose
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\family typewriter
-extern int asm_func(unsigned char, unsigned char);
-\newline
+Where to get
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-int c_func (unsigned char i, unsigned char j)
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return asm_func(i,j);
-\newline
-}
-\newline
+\layout Standard
-\newline
-int main()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\newline
+gpsim
+\begin_inset LatexCommand \index{gpsim}
-\newline
+\end_inset
-\family default
-The corresponding assembler function is:
-\newline
-\newline
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-.globl _asm_func_PARM_2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-.globl _asm_func
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-.area OSEG
-\newline
-_asm_func_PARM_2:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-.ds 1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-.area CSEG
-\newline
-_asm_func:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov a,dpl
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-add a,_asm_func_PARM_2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov dpl,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov dpl,#0x00
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-ret
-\newline
+\layout Standard
-\newline
+PIC simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\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
+
+flP5
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\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
+PIC programmer
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\begin_inset LatexCommand \url{http://digilander.libero.it/fbradasc/FLP5.html}
-dpl
-\begin_inset Quotes erd
\end_inset
- for One bye parameter,
-\begin_inset Quotes eld
+
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+srecord
+\begin_inset LatexCommand \index{srecord}
-dptr
-\begin_inset Quotes erd
\end_inset
- if two bytes,
-\begin_inset Quotes eld
+
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-b,dptr
-\begin_inset Quotes erd
+\layout Standard
+
+Object file conversion, checksumming, ...
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\begin_inset LatexCommand \url{http://srecord.sourceforge.net/}
- for three bytes and
-\begin_inset Quotes eld
\end_inset
-acc,b,dptr
-\begin_inset Quotes erd
+
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- for four bytes, the varible name for the second parameter will be _<function_na
-me>_PARM_2.
-\newline
+\layout Standard
-\newline
-Assemble the assembler routine with the following command:
-\newline
+objdump
+\begin_inset LatexCommand \index{objdump}
-\newline
+\end_inset
-\family sans
-\series bold
-asx8051 -losg asmfunc.asm
-\newline
-\newline
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family default
-\series default
-Then compile and link the assembler routine to the C source file with the
- following command:
-\newline
+\layout Standard
-\newline
+Object file conversion, ...
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\family sans
-\series bold
-sdcc cfunc.c asmfunc.rel
-\layout Subsubsection
+\layout Standard
+
+Part of binutils (should be there anyway)
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-Assembler Routine(reentrant)
\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
+doxygen
+\begin_inset LatexCommand \index{doxygen}
-\newline
+\end_inset
-\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
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-int main()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\newline
+\layout Standard
-\family default
+Source code documentation system
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-The corresponding assembler routine is:
-\newline
+\layout Standard
-\newline
-\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 ~
-clr c
-\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
-\newline
+\begin_inset LatexCommand \url{http://www.doxygen.org}
+
+\end_inset
+
+
+\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 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
+splint
+\begin_inset LatexCommand \index{splint}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-External Stack
\layout Standard
-The external stack is located at the start of the external ram segment,
- and is 256 bytes in size.
- When ---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 ---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).
+Statically checks c sources
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
\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
-ANSI-Compliance
+\begin_inset LatexCommand \url{http://www.splint.org}
+
+\end_inset
+
+
+\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
-Deviations from the compliancy.
-\layout Itemize
+ddd
+\begin_inset LatexCommand \index{ddd}
-functions are not always reentrant.
-\layout Itemize
+\end_inset
-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
+\end_inset
+</cell>
+<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
-'long long' (64 bit integers) not supported.
-\layout Itemize
+Debugger, serves nicely as GUI to sdcdb
+\begin_inset LatexCommand \index{sdcdb}
-'double' precision floating point not supported.
-\layout Itemize
+\end_inset
-No support for setjmp and longjmp (for now).
-\layout Itemize
-Old K&R style function declarations are NOT allowed.
-\newline
+\begin_inset Foot
+collapsed false
-\family typewriter
+\layout Standard
-\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
+(sdcdb and ddd are available for Unix only)
+\end_inset
-functions declared as pointers must be dereferenced during the call.
-\newline
-\family typewriter
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
+
+\end_inset
+
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
\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
+Related documentation / recommended reading
+\newline
+
\layout Standard
+\align center
-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
+\begin_inset Tabular
+<lyxtabular version="3" rows="5" 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
-\newline
-SDCC uses the following formula to compute the complexity:
-\newline
+\layout Standard
+
+Name
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-complexity = (number of edges in control flow graph) - (number of nodes
- in control flow graph) + 2;
-\newline
+Subject / Title
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\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
+\layout Standard
+
+Where to get
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+S.
+ S.
+ Muchnick
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Advanced Compiler Design and Implementation
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+bookstore
+\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
+\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">
+\begin_inset Text
-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
+C Reference Card
+\begin_inset LatexCommand \index{C Reference card}
-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
+, 2 pages
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-NEVER jump into a LOOP.
-\layout Itemize
+\layout Standard
-Declare the variables to be local 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
+\begin_inset LatexCommand \url{http://www.refcards.com/about/c.html}
-Reducing the size of division, multiplication & modulus operations can reduce
- code size substantially.
- Take the following code for example.
-\family typewriter
+\end_inset
-\newline
-\newline
-foobar(unsigned int p1, unsigned char ch)
-\newline
-{
-\newline
- unsigned char ch1 = p1 % ch ;
-\newline
- ....
-
-\newline
-}
-\newline
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family default
+\layout Standard
-\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
+test_suite_spec.pdf
+\end_inset
+</cell>
+<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
+sdcc regression test
+\begin_inset LatexCommand \index{Regression test}
-\family default
+\end_inset
-\newline
-It would substantially reduce the code generated (future versions of the
- compiler will be smart enough to detect such optimization oppurtunities).
-\layout Subsection
-Notes on MCS51 memory layout
-\layout Standard
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-The 8051 family of micro controller have a minimum of 128 bytes of internal
- memory which is structured as follows
-\newline
+\layout Standard
-\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
+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
-\newline
-Normally the SDCC compiler will only utilise the first bank of registers,
- but it is possible to specify that other banks of registers should be used
- in interrupt 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 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
-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
+\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
-The amount of stack being used is affected by the use of the "internal stack"
- to save registers before a subroutine call is made (---stack-auto 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.
- ---xstack will cause an external stack to be used for saving registers
- and (if ---stack-auto is being used) storing parameters and local variables.
- However this will produce more code which will be slower to execute.
-
-\layout Standard
+sdcc internal documentation
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
----stack-loc 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
----stack-after-data, similar to the ---stack-loc, but it automatically places
- the stack after the end of the "near data".
- Again this could waste any spare register space.
-\layout Standard
+sdcc/doc
+\end_inset
+</cell>
+</row>
+</lyxtabular>
----data-loc 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
+\end_inset
-\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 ---data-loc, e.g.
- if two register banks are being used and no bit variables, ---data-loc
- 16, and use the ---stack-after-data option.
-\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 Section
-
+\pagebreak_top
Retargetting for other MCUs.
\layout Standard
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 ---dumpraw option.
+ by using the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpraw option.
\layout Itemize
This phase does the bulk of the standard optimizations and is also MCU independe
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 is essential for register allocation, since these computati
-on determines which of these iTemps will be assigned to registers, and for
- how long.
+ Live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
+
+\end_inset
+
+ is essential for register allocation, since these computation determines
+ which of these iTemps will be assigned to registers, and for how long.
\layout Itemize
Phase five is register allocation.
As mentioned in the optimization section the peep-hole optimizer is rule
based system, which can reprogrammed for other MCUs.
\layout Section
+\pagebreak_top
+SDCDB
+\begin_inset LatexCommand \index{sdcdb}
+
+\end_inset
+
+ - Source Level Debugger
+\begin_inset LatexCommand \index{Debugger}
+
+\end_inset
+
-SDCDB - Source Level Debugger
\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 (the GNU debugger) as possible.
+ 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 Subsection
Compiling for Debugging
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.
+ The linker creates the .cdb file from the .adb files and the address information.
This .cdb is used by the debugger.
\layout Subsection
How the Debugger Works
\layout Standard
-When the ---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
+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 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.
foo.cdb - the debugger symbol information file.
\layout Itemize
-foo.ihx - the intel hex format object file.
+foo.ihx - the Intel hex format
+\begin_inset LatexCommand \index{Intel hex format}
+
+\end_inset
+
+ object file.
\layout Subsection
Command Line Options.
\layout Itemize
----directory=<source file directory> this option can used to specify the
- directory search list.
+-
+\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 ---directory option should be ---directory=/home/src1:/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
My name is Bobby Brown"
\layout Subsection
-Interfacing with XEmacs.
+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,
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
---------
+--------
\newline
;;
\newline
;;
\family default
-\newline
+\newline
+
+\layout Section
+
+Other Processors
+\layout Subsection
+
+The Z80 and gbz80 port
+\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
+ unimplemented), and both float and bitfield support is missing.
+ Apart from that the code generated is correct.
+\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 variables.
+ IY is currently unused.
+ 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}
+
+\end_inset
+
+
+\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.
+
+\layout Standard
+
+The SDCC project is hosted on the sdcc sourceforge site at
+\begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
+
+\end_inset
+
+.
+ You'll find the complete set of mailing lists
+\begin_inset LatexCommand \index{Mailing list}
+
+\end_inset
+
+, forums, bug reporting system, patch submission
+\begin_inset LatexCommand \index{Patch submission}
+
+\end_inset
+
+ system, download
+\begin_inset LatexCommand \index{download}
+
+\end_inset
+
+ area and cvs code repository
+\begin_inset LatexCommand \index{cvs code repository}
+
+\end_inset
+
+ there.
+\layout Subsection
+
+Reporting Bugs
+\begin_inset LatexCommand \index{Bugs}
+
+\end_inset
+
-\layout Section
+\begin_inset LatexCommand \index{Reporting bugs}
-Other Processors
+\end_inset
+
+
+\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.
+\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
+ (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
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpall
+\begin_inset LatexCommand \index{-\/-dumpall}
+
+\end_inset
+
+ option can sometimes be useful in locating optimization problems.
+ When reporting a bug please maker sure you:
+\layout Enumerate
+
+Attach the code you are compiling with SDCC.
+
+\layout Enumerate
+
+Specify the exact command you use to run SDCC, or attach your Makefile.
+
+\layout Enumerate
+
+Specify the SDCC version (type "sdcc -v"), your platform, and operating
+ system.
+
+\layout Enumerate
+
+Provide an exact copy of any error message or incorrect output.
+
+\layout Enumerate
+
+Put something meaningful in the subject of your message.
+\layout Standard
+
+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
+
+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}
+
+\end_inset
+
+.
\layout Subsection
-The Z80 and gbz80 port
+Requesting Features
+\begin_inset LatexCommand \index{Feature request}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Requesting features}
+
+\end_inset
+
+
\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.
+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}
+
+\end_inset
+
+.
+\layout Subsection
+
+Getting Help
\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
+These links should take you directly to the
+\begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
+
+\end_inset
+
+
+\begin_inset Foot
+collapsed false
-Support
\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.
+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}
+
+\end_inset
+
+, lists and forums are archived so if you are lucky someone already had
+ a similar problem.
\layout Subsection
-Reporting Bugs
+ChangeLog
+\begin_inset LatexCommand \index{Changelog}
+
+\end_inset
+
+
\layout Standard
-Send an email to the mailing list at 'user-sdcc@sdcc.sourceforge.net' or 'devel-sd
-cc@sdcc.sourceforge.net'.
- Bugs 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 ---dumpall option can sometimes be useful
- in locating optimization problems.
-\layout Section
+You can follow the status of the cvs version
+\begin_inset LatexCommand \index{version}
+
+\end_inset
+
+ 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}
+
+\end_inset
+
+ in the cvs-repository.
+\layout Subsection
+
+Release policy
+\begin_inset LatexCommand \index{Release policy}
+
+\end_inset
+
+
+\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! On the other hand there are
+ daily snapshots available at
+\begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
+
+\end_inset
+
+, and you can always built 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}
+
+\end_inset
+
+.
+\layout Subsection
+
+Examples
+\begin_inset LatexCommand \index{Examples}
+
+\end_inset
+
+\layout Standard
+
+You'll find some small examples in the directory sdcc/device/examples/
+\layout Comment
+
+Maybe we should include some links to real world applications.
+ Preferably pointer to pointers (one for each architecture) so this stays
+ manageable here?
+\layout Subsection
+
+Quality control
+\begin_inset LatexCommand \index{Quality control}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler is passed through nightly compile and build checks.
+ The so called
+\shape italic
+regression tests
+\shape default
+
+\begin_inset LatexCommand \index{Regression test}
+
+\end_inset
+
+ 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}
+
+\end_inset
+
+
+\shape default
+ about this.
+\layout Standard
+
+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}
+
+\end_inset
+
+ checking corner cases of SDCC or if you plan to submit patches
+\begin_inset LatexCommand \index{Patch submission}
+
+\end_inset
+
+.
+\layout Standard
+
+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
The anatomy of the compiler
\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/devell
-oper friendly), but pretty well exposes the guts of it all.
+ 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.
\shape default
\newline
\layout Paragraph*
-Parsing
+Parsing
+\begin_inset LatexCommand \index{Parsing}
+
+\end_inset
+
+
\layout Standard
-Parsing the input source file and creating an AST (Annotated Syntax Tree).
+Parsing the input source file and creating an AST (Annotated Syntax Tree
+\begin_inset LatexCommand \index{Annotated syntax tree}
+
+\end_inset
+
+).
This phase also involves propagating types (annotating each node of the
parse tree with type information) and semantic analysis.
There are some MCU specific parsing rules.
\layout Paragraph*
Generating iCode
+\begin_inset LatexCommand \index{iCode}
+
+\end_inset
+
+
\layout Standard
Intermediate code generation.
C source functions.
\layout Paragraph*
-Optimizations.
+Optimizations
+\begin_inset LatexCommand \index{Optimizations}
+
+\end_inset
+
+.
\layout Standard
Bulk of the target independent optimizations is performed in this phase.
\layout Paragraph*
Live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
+
+\end_inset
+
+
\layout Standard
During intermediate code generation phase, the compiler assumes the target
\layout Paragraph*
Register Allocation
+\begin_inset LatexCommand \index{Register allocation}
+
+\end_inset
+
+
\layout Standard
The register allocation determines the type and number of registers needed
\layout Paragraph*
ICode Example
+\begin_inset LatexCommand \index{iCode}
+
+\end_inset
+
+
\layout Standard
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 ~
\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 ~
\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:
generated temporary b) user defined variable c) a constant value.
Note that local variables and parameters are replaced by compiler generated
temporaries.
- Live ranges are computed only for temporaries (i.e.
+ Live ranges
+\begin_inset LatexCommand \index{Live range analysis}
+
+\end_inset
+
+ are computed only for temporaries (i.e.
live ranges are not computed for global variables).
- Registers are allocated for temporaries only.
+ Registers
+\begin_inset LatexCommand \index{Register allocation}
+
+\end_inset
+
+ are allocated for temporaries only.
Operands are formatted in the following manner:
\newline
the temporary is used only for a conditional jump the code generation makes
use of this information to optimize a compare and jump ICode.
\newline
-There are several loop optimizations performed by the compiler.
+There are several loop optimizations
+\begin_inset LatexCommand \index{Loop optimization}
+
+\end_inset
+
+ performed by the compiler.
It can detect induction variables iTemp21(i) and iTemp23(j).
- Also note the compiler does selective strength reduction, i.e.
+ Also note the compiler does selective strength reduction
+\begin_inset LatexCommand \index{Strength reduction}
+
+\end_inset
+
+, i.e.
the multiplication of an induction variable in line 18 (gint = j * 3) is
changed to addition, a new temporary iTemp17 is allocated and assigned
a initial value, a constant 3 is then added for each iteration of the loop.
- The compiler does not change the multiplication in line 17 however since
- the processor does support an 8 * 8 bit multiplication.
+ The compiler does not change the multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ in line 17 however since the processor does support an 8 * 8 bit multiplication.
\newline
-Note the dead code elimination optimization eliminated the dead assignments
- in line 7 & 8 to I and sum respectively.
+Note the dead code elimination
+\begin_inset LatexCommand \index{Dead-code elimination}
+
+\end_inset
+
+ optimization eliminated the dead assignments in line 7 & 8 to I and sum
+ respectively.
\newline
\layout Standard
A few words about basic block successors, predecessors and dominators
\layout Standard
-Successors are basic blocks that might execute after this basic block.
+Successors are basic blocks
+\begin_inset LatexCommand \index{Basic blocks}
+
+\end_inset
+
+ that might execute after this basic block.
\newline
Predecessors are basic blocks that might execute before reaching this basic
block.
This document was initially written by Sandeep Dutta
\layout Standard
-All product names mentioned herein may be trademarks of their respective
- companies.
+All product names mentioned herein may be trademarks
+\begin_inset LatexCommand \index{Trademarks}
+
+\end_inset
+
+ of their respective companies.
+\layout Section
+
+Alphabetical index
+\layout Standard
+
+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