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-\lyxformat 220
+#LyX 1.3 created this file. For more info see http://www.lyx.org/
+\lyxformat 221
\textclass article
\begin_preamble
-\usepackage[colorlinks=true,linkcolor=blue]{hyperref}
+\usepackage[
+ pdftitle={SDCC Compiler User Guide},
+ pdfauthor={SDCC development team},
+ pdfsubject={installation, user manual},
+ pdfkeywords={8032, 8051, ansi, c, compiler, CPU, DS390,
+ embedded, GPL, manual, mcs51, PIC, small, Z80},
+ colorlinks=true,
+ linkcolor=blue] {hyperref}
+\date{}
\end_preamble
\language english
\inputencoding default
\graphics default
\paperfontsize default
\spacing single
-\papersize Default
+\papersize letterpaper
\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
+
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+
+\backslash
+/
+\end_inset
+
+-
+\layout Comment
+
+Two resp.
+ three consecutive dashes simply result in a long resp.
+ extra long dash.
+\layout Comment
+
+Architecture specific stuff (like memory models, code examples) should maybe
+ 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
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 Microchip
+ PIC, Atmel AVR is under development.
The entire source code for the compiler is distributed under GPL.
SDCC uses ASXXXX & ASLINK, a Freeware, retargettable assembler & linker.
SDCC has extensive language extensions suitable for utilizing various microcont
dead code elimination
\layout Itemize
-jumptables for
+jump tables for
\emph on
switch
\emph default
\newline
\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
\newline
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License
-\begin_inset LatexCommand \index{GNU General Public License}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{GPL}
+\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
+
\newline
\family default
-If you can think of some more, please send them to the list.
+If you can think of some more, please see the chapter
+\begin_inset LatexCommand \ref{sub:Requesting-Features}
+
+\end_inset
+
+ about filing feature requests
+\begin_inset LatexCommand \index{Requesting features}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Feature request}
+
+\end_inset
+
+.
\newline
\layout Section
-
-Installation
+\pagebreak_top
+Installing SDCC
\begin_inset LatexCommand \index{Installation}
\end_inset
+\layout Standard
+
+For most users it is sufficient to skip to either section
+\begin_inset LatexCommand \ref{sub:Building-SDCC-on-Linux}
+
+\end_inset
+
+ or section
+\begin_inset LatexCommand \ref{sub:Windows-Install}
+
+\end_inset
+
+.
+ More detailled instructions follow below.
\layout Subsection
Configure Options
-\begin_inset LatexCommand \index{Configure Options}
+\begin_inset LatexCommand \index{Options SDCC configuration}
\end_inset
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
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+status Collapsed
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\layout List
\labelwidthstring 00.00.0000
----exec_prefix see tabel below
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\labelwidthstring 00.00.0000
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+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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+-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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\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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\layout List
\labelwidthstring 00.00.0000
----disable-avr-port Excludes the AVR port
+-
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\layout List
\labelwidthstring 00.00.0000
----disable-ds390-port Excludes the DS390 port
+-
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\layout List
\labelwidthstring 00.00.0000
----disable-pic-port Excludes the PIC port
+-
+\begin_inset ERT
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+-disable-pic-port Excludes the PIC port
\layout List
\labelwidthstring 00.00.0000
----disable-xa51-port Excludes the XA51 port
+-
+\begin_inset ERT
+status Collapsed
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+\layout Standard
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+\backslash
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+-disable-xa51-port Excludes the XA51 port
\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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----enable-libgc Use the Bohem memory allocator.
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Lower runtime footprint.
\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
+status Collapsed
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+\layout Standard
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These defaults are:
\newline
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<lyxtabular version="3" rows="8" columns="3">
<features>
-<column alignment="left" valignment="top" leftline="true" width="0in">
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-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
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-
-\newline
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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
-\newline
+\layout Standard
+\align center
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
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\begin_inset Text
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..
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\newline
-\newline
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Examples:
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-\layout LyX-Code
+\newline
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+\begin_inset ERT
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-\begin_inset Quotes srd
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\layout Standard
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-2'):
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\backslash
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\begin_inset Quotes srd
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\begin_inset Quotes srd
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\layout Standard
To
\begin_inset Quotes srd
\end_inset
-compile on Cygwin for Mingw32(see also sdcc/support/scripts/sdcc_cygwin_mingw32)
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+status Collapsed
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+\layout Standard
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\layout Subsection
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-
-1.
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-\layout Standard
-
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\begin_inset Tabular
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+<lyxtabular version="3" rows="5" columns="4">
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<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\layout Standard
-Win32 builds
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\end_inset
</cell>
</row>
-<row topline="true" bottomline="true">
-<cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
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+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
\emph on
-$DATADIR/
-\newline
-$INCLUDE_DIR_SUFFIX
+$DATADIR/$LIB_DIR_SUFFIX
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-/usr/local/share/sdcc/include
+/usr/local/share/sdcc/lib
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
\backslash
sdcc
\backslash
-include
+lib
\end_inset
</cell>
</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
-
-\newline
-3.
- Library files (the
-\shape italic
-model
-\shape default
- is auto-appended by the compiler, e.g.
- small, large, z80, ds390 etc.)
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="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
+Documentation
\end_inset
</cell>
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\layout Standard
-default
+
+\emph on
+$DOCDIR
\end_inset
</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-
-\emph on
-$DATADIR/$LIB_DIR_SUFFIX
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-/usr/local/share/sdcc/lib
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-
-\backslash
-sdcc
-\backslash
-lib
-\end_inset
-</cell>
-</row>
-</lyxtabular>
-
-\end_inset
-
-
-\newline
-
-\newline
-4.
- Documentation
-\layout Standard
-
-
-\begin_inset Tabular
-<lyxtabular version="3" rows="2" columns="3">
-<features>
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Path
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-default
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-Win32 builds
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\layout Standard
-
-
-\emph on
-$DOCDIR
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\layout Standard
\end_inset
-\newline
+\layout Verse
+
+\size footnotesize
+*compiler, preprocessor, assembler, and linker
\newline
+**the
+\shape italic
+model
+\shape default
+ is auto-appended by the compiler, e.g.
+ small, large, z80, ds390 etc
+\layout Standard
+\noindent
The install paths can still be changed during `make install` with e.g.:
\layout LyX-Code
\layout Subsection
Search Paths
-\begin_inset LatexCommand \index{Search Paths}
+\begin_inset LatexCommand \index{Search path}
\end_inset
1.
Binary files (preprocessor, assembler and linker)
\newline
-
+
+\layout Standard
+\align center
+
\begin_inset Tabular
<lyxtabular version="3" rows="4" columns="3">
<features>
-<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
\layout Subsubsection
Building SDCC on Linux
+\begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}
+
+\end_inset
+
+
\layout Enumerate
./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
They use Unix-sockets, which are not available on Win32.
\layout Subsubsection
-Windows Install Using a Binary Package
-\layout Enumerate
-
-Download the binary package and unpack it using your favorite unpacking
- tool (gunzip, WinZip, etc).
- This should unpack to a group of sub-directories.
- An example directory structure after unpacking the mingw32 package is:
- c:
-\backslash
-sdcc
-\backslash
-bin for the executables, c:
-\backslash
-sdcc
-\backslash
-include and c:
-\backslash
-sdcc
-\backslash
-lib for the include and libraries.
-\layout Enumerate
-
-Adjust your environment variable PATH to include the location of the bin
- directory or start sdcc using the full path.
-\layout Subsubsection
-
Building SDCC using Cygwin and Mingw32
\layout Standard
Win32-binary can be built, which will not need the Cygwin-DLL.
For the necessary 'configure' options see section 'configure options' or
- the script 'sdcc/support/scripts/sdcc_cygwinmingw32'.
+ the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
\newline
\newline
Replace in your cygwin.bat the line
\layout LyX-Code
-bash --login -i
+bash -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-login -i
\layout Standard
with (one line):
rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
\layout LyX-Code
- -bg black -fg white -geometry 100x65 -e bash --login
+ -bg black -fg white -geometry 100x65 -e bash -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-login
\layout Standard
Text selected with the mouse is automatically copied to the clipboard, pasting
\layout Standard
SDCC sources use the unix line ending LF.
- Life is much easier, if you store the source tree on a drive, which is
- mount in binary mode.
+ Life is much easier, if you store the source tree on a drive which is mounted
+ in binary mode.
And use an editor which can handle LF-only line endings.
Make sure not to commit files with windows line endings.
+ The tabulator spacing used in the project is 8.
\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}
\end_inset
.zip.
- Now you have to install the utilities and setup Visual C++ so it can locate
- the required programs.
+ Now you have to install the utilities and setup MSVC so it can locate the
+ required programs.
Here there are two alternatives (choose one!):
\layout Enumerate
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 (be
+ sure you are in the sdcc directory):
\newline
\newline
\newline
\newline
-or on Windows NT/2000/XP from the command prompt with the commmand:
+or on Windows NT/2000/XP from the command prompt with the command:
\newline
\family sans
\family default
\series default
from the sdcc directory.
-\layout Subsection
+\layout Subsubsection
-Building the Documentation
-\layout Standard
+Windows Install Using a Binary Package
+\begin_inset LatexCommand \label{sub:Windows-Install}
-...
- coming soon
-\layout Subsection
+\end_inset
-Testing out the SDCC Compiler
-\layout Standard
-The first thing you should do after installing your SDCC compiler is to
- see if it runs.
- Type
-\family sans
-\series bold
-"sdcc ---version"
-\begin_inset LatexCommand \index{version}
+\layout Enumerate
+
+Download the binary package from
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
\end_inset
+ and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
+ This should unpack to a group of sub-directories.
+ An example directory structure after unpacking the mingw32 package is:
+ c:
+\backslash
+sdcc
+\backslash
+bin for the executables, c:
+\backslash
+sdcc
+\backslash
+include and c:
+\backslash
+sdcc
+\backslash
+lib for the include and libraries.
+\layout Enumerate
-\family default
+Adjust your environment variable PATH to include the location of the bin
+ directory or start sdcc using the full path.
+\layout Subsection
+
+Building the Documentation
+\layout Standard
+
+If the necessary tools are installed it is as easy as changing into the
+ doc directory and typing
+\family sans
+\series bold
+
+\begin_inset Quotes srd
+\end_inset
+
+make
+\begin_inset Quotes srd
+\end_inset
+
+
+\family default
+\series default
+ there.
+ If you want to avoid installing the tools you will have some success with
+ a bootable Knoppix CD
+\begin_inset LatexCommand \url{http://www.knopper.net}
+
+\end_inset
+
+.
+\layout Subsection
+
+Testing the SDCC Compiler
+\layout Standard
+
+The first thing you should do after installing your SDCC compiler is to
+ see if it runs.
+ Type
+\family sans
+\series bold
+"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.
If it doesn't run, or gives a message about not finding sdcc program, then
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}
+\begin_inset LatexCommand \index{Install trouble-shooting}
\end_inset
\layout Standard
This will install the compiler, other executables libraries and include
- files in to the appropriate directories.
+ files into the appropriate directories.
See section
\begin_inset Quotes sld
\end_inset
.
\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.
This is retargettable assembler & linkage editor, it was developed by Alan
Baldwin.
John Hartman created the version for 8051, and I (Sandeep) have made some
- enhancements and bug fixes for it to work properly with the SDCC.
+ enhancements and bug fixes for it to work properly with SDCC.
\layout Subsubsection
s51 - The Simulator
-\begin_inset LatexCommand \index{s51 - The Simulator}
+\begin_inset LatexCommand \index{s51}
\end_inset
).
The simulator is built as part of the build process.
- For more information visit Daniel's website at:
+ For more information visit Daniel's web site at:
\begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
\end_inset
.
- It currently support the core mcs51, the Dallas DS80C390 and the Philips
+ It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
XA51 family.
\layout Subsubsection
-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
\begin_inset LatexCommand \index{.asm}
\end_inset
- - Assembler source file created by the compiler
-\newline
+ - 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 file created by the Assembler
-\newline
+ - 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 file updated with linkedit information, created by
- linkage editor
-\newline
+ - 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 for the sourcefile, created by the assembler
-\newline
+ - 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 created by the assembler, input to Linkage editor
-\newline
+ - 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 for the load module, created by the Linker
-\newline
+ - 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 ussage
-\newline
+ - 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 (you can select the Motorola S19
- format with ---out-fmt-s19)
-\newline
+ - 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
+\family sans
+\shape italic
+objdump
+\family default
+\shape default
+
+\begin_inset LatexCommand \index{objdump}
+
+\end_inset
+
+ or
+\family sans
+\shape italic
+ srecord
+\family default
+\shape default
+
+\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 ---debug)
-\newline
+ .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 ---debug) containing debug information
-\newline
+ - 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 ---debug)
-\newline
+ An optional AOMF51
+\begin_inset LatexCommand \index{AOMF51}
+
+\end_inset
+
+ file containing debug information (with -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug).
+ This format is commonly used by third party tools (debuggers
+\begin_inset LatexCommand \index{Debugger}
+
+\end_inset
+
+, simulators, emulators)
+\layout Itemize
+
sourcefile.dump*
\begin_inset LatexCommand \index{.dump*}
\end_inset
- - Dump file to debug the compiler it self (with ---dumpall) (see section
-
+ - 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
\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 Subsubsection
Processor Selection Options
-\begin_inset LatexCommand \index{Processor Selection Options}
+\begin_inset LatexCommand \index{Options processor selection}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Processor selection options}
\end_inset
\series default
- Generate code for the MCS51 (8051) family of processors.
+ Generate code for the Intel MCS51
+\begin_inset LatexCommand \index{MCS51}
+
+\end_inset
+
+ family of processors.
This is the default processor target.
\layout List
\labelwidthstring 00.00.0000
\series default
- Generate code for the DS80C390 processor.
+ Generate code for the Dallas DS80C390
+\begin_inset LatexCommand \index{DS80C390}
+
+\end_inset
+
+ processor.
\layout List
\labelwidthstring 00.00.0000
\series bold
--mz80
-\begin_inset LatexCommand \index{-mz80}
+-mds400
+\begin_inset LatexCommand \index{-mds400}
\end_inset
\series default
- Generate code for the Z80 family of processors.
-\layout List
+ Generate code for the Dallas DS80C400
+\begin_inset LatexCommand \index{DS80C400}
+
+\end_inset
+
+ processor.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mz80
+\begin_inset LatexCommand \index{-mz80}
+
+\end_inset
+
+
+\series default
+ Generate code for the Zilog Z80
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ family of processors.
+\layout List
\labelwidthstring 00.00.0000
\series default
- Generate code for the GameBoy Z80 processor.
+ Generate code for the GameBoy Z80
+\begin_inset LatexCommand \index{GameBoy Z80}
+
+\end_inset
+
+ processor.
\layout List
\labelwidthstring 00.00.0000
\series default
- Generate code for the Atmel AVR processor (In development, not complete).
+ Generate code for the Atmel AVR
+\begin_inset LatexCommand \index{AVR}
+
+\end_inset
+
+ processor (In development, not complete).
+ AVR users should probably have a look at avr-gcc
+\begin_inset LatexCommand \url{ http://savannah.nongnu.org/download/avr-libc/snapshots/}
+
+\end_inset
+
+.
+\layout Comment
+
+I think it is fair to direct users there for now.
+ Open source is also about avoiding unnecessary work .
+ But I didn't find the 'official' link.
\layout List
\labelwidthstring 00.00.0000
\series default
- Generate code for the PIC 14-bit processors (In development, not complete).
+ Generate code for the Microchip PIC 14
+\begin_inset LatexCommand \index{PIC14}
+
+\end_inset
+
+-bit processors (p16f84 and variants).
+\layout Comment
+
+p16f627 p16f628 p16f84 p16f873 p16f877?
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-mpic16
+\begin_inset LatexCommand \index{-mpic16}
+
+\end_inset
+
+
+\series default
+ Generate code for the Microchip PIC 16
+\begin_inset LatexCommand \index{PIC16}
+
+\end_inset
+
+-bit processors (p18f452 and variants).
\layout List
\labelwidthstring 00.00.0000
\series bold
-mtlcs900h
\series default
- Generate code for the Toshiba TLCS-900H processor (In development, not
- complete).
+ 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 default
- Generate code for the Philips XA51 processor (In development, not complete).
+ 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}
+\begin_inset LatexCommand \index{Options preprocessor}
\end_inset
-\begin_inset LatexCommand \index{Preprocessor Options}
+\begin_inset LatexCommand \index{Preprocessor options}
\end_inset
\series default
Command line definition of macros.
- Passed to the pre processor.
+ Passed to the preprocessor.
\layout List
\labelwidthstring 00.00.0000
'-newline if it is long.
The list of rules is printed on standard output instead of the preprocessed
C program.
- `-M' implies `-E'.
+ `-M' implies `-E
+\begin_inset LatexCommand \index{-E}
+
+\end_inset
+
+'.
\layout List
\labelwidthstring 00.00.0000
\labelwidthstring 00.00.0000
-\series bold
--Aquestion
-\series default
- (answer) Assert the answer answer for question, in case it is tested with
- a preprocessor conditional such as `#if #question(answer)'.
- `-A-' disables the standard assertions that normally describe the target
- machine.
-\layout List
-\labelwidthstring 00.00.0000
-
-
\series bold
-Umacro
\begin_inset LatexCommand \index{-Umacro}
\layout Subsubsection
Linker Options
-\begin_inset LatexCommand \index{Options Linker}
+\begin_inset LatexCommand \index{Options linker}
\end_inset
-\begin_inset LatexCommand \index{Linker Options}
+\begin_inset LatexCommand \index{Linker options}
\end_inset
\series bold
-L\SpecialChar ~
----lib-path
-\begin_inset LatexCommand \index{-L ---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
\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
-\begin_inset LatexCommand \index{---xram-loc}
+\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
-<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.
+-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
-\begin_inset LatexCommand \index{---code-loc}
+\begin_inset LatexCommand \index{-\/-code-loc}
+
+\end_inset
+
+<Value> The start location of the code
+\begin_inset LatexCommand \index{code}
\end_inset
-<Value> The start location of the code segment, default value 0.
+ 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
-\begin_inset LatexCommand \index{---stack-loc}
+\begin_inset LatexCommand \index{-\/-stack-loc}
+
+\end_inset
+
+<Value> By default the stack
+\begin_inset LatexCommand \index{stack}
\end_inset
-<Value> By default the stack is placed after the data segment.
+ 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
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-data-loc
\series default
-\begin_inset LatexCommand \index{---data-loc}
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+<Value> The start location of the internal ram data
+\begin_inset LatexCommand \index{data}
\end_inset
-<Value> The start location of the internal ram data segment.
+ segment.
The value entered can be in Hexadecimal or Decimal format, eg.
- ---data-loc 0x20 or ---data-loc 32.
+ -
+\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 ---data-loc is not used, to location 0x10.)
+ 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
----idata-loc
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-idata-loc
\series default
-\begin_inset LatexCommand \index{---idata-loc}
+\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
-<Value> The start location of the indirectly addressable internal ram, default
- value is 0x80.
+, default value is 0x80.
The value entered can be in Hexadecimal or Decimal format, eg.
- ---idata-loc 0x88 or ---idata-loc 136.
+ -
+\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
----out-fmt-ihx
-\begin_inset LatexCommand \index{---out-fmt-ihx}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-out-fmt-ihx
+\begin_inset LatexCommand \index{-\/-out-fmt-ihx}
\end_inset
\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
----out-fmt-s19
-\begin_inset LatexCommand \index{---out-fmt-s19}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-out-fmt-s19
+\begin_inset LatexCommand \index{-\/-out-fmt-s19}
\end_inset
\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
\end_inset
-\begin_inset LatexCommand \index{MCS51 Options}
+\begin_inset LatexCommand \index{MCS51 options}
\end_inset
\series bold
----model-large
-\begin_inset LatexCommand \index{---model-large}
-
-\end_inset
+-
+\begin_inset ERT
+status Collapsed
+\layout Standard
-\series default
- Generate code for Large model programs see section Memory Models for more
- details.
- If this option is used all source files in the project should be compiled
- with this option.
- In addition the standard library routines are compiled with small model,
- they will need to be recompiled.
-\layout List
-\labelwidthstring 00.00.0000
-
+\backslash
+/
+\end_inset
-\series bold
----model-small
-\begin_inset LatexCommand \index{---model-small}
+-model-small
+\begin_inset LatexCommand \index{-\/-model-small}
\end_inset
Generate code for Small Model programs see section Memory Models for more
details.
This is the default model.
-\layout Subsubsection
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\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.
+ If this option is used all source files in the project should be compiled
+ with this option.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+
+\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
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-iram-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-iram-size<Value>}
+
+\end_inset
+
+ Causes the linker to check if the internal ram usage is within limits of
+ the given value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xram-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-xram-size<Value>}
+
+\end_inset
+
+ Causes the linker to check if the external ram usage is within limits of
+ the given value.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-code-size
+\series default
+<Value>
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+ Causes the linker to check if the code memory usage is within limits of
+ the given value.
+\layout Subsubsection
DS390 Options
\begin_inset LatexCommand \index{Options DS390}
\end_inset
-\begin_inset LatexCommand \index{DS390 Options}
+\begin_inset LatexCommand \index{DS390 options}
\end_inset
\series bold
----model-flat24
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-model-flat24
\series default
-\begin_inset LatexCommand \index{---model-flat24}
+\begin_inset LatexCommand \index{-\/-model-flat24}
\end_inset
\series bold
----stack-10bit
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-10bit
\series default
-\begin_inset LatexCommand \index{--stack-10bit}
+\begin_inset LatexCommand \index{-\/-stack-10bit}
\end_inset
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
+Z80 Options
+\begin_inset LatexCommand \index{Options Z80}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Z80 options}
+
+\end_inset
+
+
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-callee-saves-bc
+\series default
+
+\begin_inset LatexCommand \index{-\/-callee-saves-bc}
+
+\end_inset
+
+
+\size large
+\emph on
+
+\size default
+\emph default
+Force a called function to always save BC.
+\layout List
+\labelwidthstring 00.00.0000
+
+
+\series bold
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-no-std-crt0
+\series default
+
+\begin_inset LatexCommand \index{-\/-no-std-crt0}
+
+\end_inset
+
+ When linking, skip the standard crt0.o object file.
+ You must provide your own crt0.o for your system when linking.
+
+\layout Subsubsection
+
Optimization Options
-\begin_inset LatexCommand \index{Options Optimization}
+\begin_inset LatexCommand \index{Options optimization}
\end_inset
-\begin_inset LatexCommand \index{Optimization Options}
+\begin_inset LatexCommand \index{Optimization options}
\end_inset
\series bold
----nogcse
-\begin_inset LatexCommand \index{---nogcse}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nogcse
+\begin_inset LatexCommand \index{-\/-nogcse}
\end_inset
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.
+NOGCSE
+\begin_inset LatexCommand \index{\#pragma NOGCSE}
+
+\end_inset
+
+ can be used to turn off global subexpression elimination
+\begin_inset LatexCommand \index{Subexpression elimination}
+
+\end_inset
+
+ for a given function only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----noinvariant
-\begin_inset LatexCommand \index{---noinvariant}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noinvariant
+\begin_inset LatexCommand \index{-\/-noinvariant}
\end_inset
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.
+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
----noinduction
-\begin_inset LatexCommand \index{---noinduction}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noinduction
+\begin_inset LatexCommand \index{-\/-noinduction}
\end_inset
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.
+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
----nojtbound
-\begin_inset LatexCommand \index{---nojtbound}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nojtbound
+\begin_inset LatexCommand \index{-\/-nojtbound}
\end_inset
\series default
\size default
\bar default
- Will not generate boundary condition check when switch statements are implement
-ed using jump-tables.
+ Will not generate boundary condition check when switch statements
+\begin_inset LatexCommand \index{switch statement}
+
+\end_inset
+
+ are implemented 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
+NOJTBOUND
+\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+
+\end_inset
+
+ can be used to turn off boundary checking for jump tables for a given function
only.
\layout List
\labelwidthstring 00.00.0000
\series bold
----noloopreverse
-\begin_inset LatexCommand \index{---noloopreverse}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-noloopreverse
+\begin_inset LatexCommand \index{-\/-noloopreverse}
\end_inset
\size large
\size default
-Will not do loop reversal optimization.
+Will not do loop reversal
+\begin_inset LatexCommand \index{Loop reversing}
+
+\end_inset
+
+optimization.
\layout List
\labelwidthstring 00.00.0000
----
-\series bold
-nolabelopt
-\series default
-
-\begin_inset LatexCommand \index{---nolabelopt }
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-
+\series bold
+nolabelopt
+\series default
+
+\begin_inset LatexCommand \index{-\/-nolabelopt }
\end_inset
\series bold
----no-xinit-opt
-\begin_inset LatexCommand \index{---no-xinit-opt}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-no-xinit-opt
+\begin_inset LatexCommand \index{-\/-no-xinit-opt}
\end_inset
\series default
- Will not memcpy initialized data in far space from code space.
+ Will not memcpy initialized data from code space into xdata space.
This saves a few bytes in code space if you don't have initialized data.
\layout Subsubsection
\end_inset
-\begin_inset LatexCommand \index{Other Options}
-
-\end_inset
-
-
\layout List
\labelwidthstring 00.00.0000
\series bold
-c\SpecialChar ~
----compile-only
-\begin_inset LatexCommand \index{---compile-only}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-compile-only
+\begin_inset LatexCommand \index{-\/-compile-only}
\end_inset
-\begin_inset LatexCommand \index{-c ---compile-only}
+\begin_inset LatexCommand \index{-c -\/-compile-only}
\end_inset
\series bold
---c1mode
-\begin_inset LatexCommand \index{--c1mode}
+-
+\series default
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+-c1mode
+\begin_inset LatexCommand \index{-\/-c1mode}
\end_inset
\series bold
----stack-auto
-\begin_inset LatexCommand \index{---stack-auto}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
\end_inset
\emph on
reentrant
\emph default
+
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
, i.e.
- the parameters and local variables will be allocated on the stack.
+ the parameters and local variables will be allocated on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+.
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.
\series bold
----xstack
-\begin_inset LatexCommand \index{---xstack}
-
-\end_inset
-
+-
+\begin_inset ERT
+status Collapsed
-\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
+\layout Standard
+\backslash
+/
+\end_inset
-\series bold
----callee-saves
-\begin_inset LatexCommand \index{---callee-saves}
+-callee-saves
+\begin_inset LatexCommand \index{-\/-callee-saves}
\end_inset
\series default
The compiler by default uses a caller saves convention for register saving
- across function calls, however this can cause unneccessary register pushing
+ 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 interprocedural analysis) will be able
+ code will be generated at the entry & exit (function prologue
+\series bold
+
+\begin_inset LatexCommand \index{function prologue}
+
+\end_inset
+
+
+\series default
+ & epilogue
+\series bold
+
+\begin_inset LatexCommand \index{function epilogue}
+
+\end_inset
+
+
+\series default
+) 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 _muluint..., if this
+ 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 ---callee-saves option string.
+ should be compiled with the same -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-callee-saves option string.
Also see #pragma\SpecialChar ~
CALLEE-SAVES
\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
\series bold
----debug
-\begin_inset LatexCommand \index{---debug}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
\end_inset
\labelwidthstring 00.00.0000
-\series bold
----peep-file
-\series default
-
-\begin_inset LatexCommand \index{---peep-file}
-
-\end_inset
-
-<filename> This option can be used to use additional rules to be used by
- the peep hole optimizer.
- See section Peep Hole optimizations for details on how to write these rules.
-\layout List
-\labelwidthstring 00.00.0000
-
-
\series bold
-S
\begin_inset LatexCommand \index{-S}
\series bold
----int-long-reent
-\begin_inset LatexCommand \index{---int-long-reent}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-int-long-reent
+\begin_inset LatexCommand \index{-\/-int-long-reent}
\end_inset
\series bold
----cyclomatic
-\begin_inset LatexCommand \index{---cyclomatic}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-cyclomatic
+\begin_inset LatexCommand \index{-\/-cyclomatic}
\end_inset
graph of the function, and most importantly the
\emph on
cyclomatic complexity
-\begin_inset LatexCommand \index{cyclomatic complexity}
+\begin_inset LatexCommand \index{Cyclomatic complexity}
\end_inset
\series bold
----float-reent
-\begin_inset LatexCommand \index{---float-reent}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-float-reent
+\begin_inset LatexCommand \index{-\/-float-reent}
\end_inset
\series default
\bar default
Floating point library is compiled as reentrant
-\begin_inset LatexCommand \index{ reentrant}
+\begin_inset LatexCommand \index{reentrant}
\end_inset
-.See section Installation for more details.
+.
+ See section Installation for more details.
\layout List
\labelwidthstring 00.00.0000
\series bold
----nooverlay
-\begin_inset LatexCommand \index{---nooverlay}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nooverlay
+\begin_inset LatexCommand \index{-\/-nooverlay}
\end_inset
\series bold
----main-return
-\begin_inset LatexCommand \index{---main-return}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-main-return
+\begin_inset LatexCommand \index{-\/-main-return}
\end_inset
function.
The default option is to lock up i.e.
- generate a 'ljmp '.
+ generate a '
+\family typewriter
+ljmp .
+\family default
+'.
\layout List
\labelwidthstring 00.00.0000
\series bold
----no-peep
-\begin_inset LatexCommand \index{---no-peep}
+-
+\begin_inset ERT
+status Collapsed
-\end_inset
+\layout Standard
+\backslash
+/
+\end_inset
+-peep-file
\series default
- Disable peep-hole optimization.
+
+\begin_inset LatexCommand \index{-\/-peep-file}
+
+\end_inset
+
+<filename> This option can be used to use additional rules to be used by
+ the peep hole optimizer.
+ See section Peep Hole optimizations for details on how to write these rules.
\layout List
\labelwidthstring 00.00.0000
\series bold
----peep-asm
-\begin_inset LatexCommand \index{---peep-asm}
+-
+\begin_inset ERT
+status Collapsed
-\end_inset
+\layout Standard
+\backslash
+/
+\end_inset
-\series default
- Pass the inline assembler code through the peep hole optimizer.
- This can cause unexpected changes to inline assembler code, please go through
- the peephole optimizer
-\begin_inset LatexCommand \index{Peephole optimizer}
+-no-peep
+\begin_inset LatexCommand \index{-\/-no-peep}
\end_inset
- rules defined in the source file tree '<target>/peeph.def' before using
- this option.
+
+\series default
+ Disable peep-hole optimization.
\layout List
\labelwidthstring 00.00.0000
\series bold
----iram-size
-\series default
-<Value>
-\begin_inset LatexCommand \index{---iram-size<Value>}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+\backslash
+/
\end_inset
- Causes the linker to check if the internal ram usage is within limits of
- the given value.
-\layout List
-\labelwidthstring 00.00.0000
+-peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
+
+\end_inset
-\series bold
----xram-size
\series default
-<Value>
-\begin_inset LatexCommand \index{---xram-size<Value>}
+ 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
- Causes the linker to check if the external ram usage is within limits of
- the given value.
+ rules defined in the source file tree '<target>/peeph.def' before using
+ this option.
\layout List
\labelwidthstring 00.00.0000
\series bold
----code-size
-\series default
-<Value>
-\begin_inset LatexCommand \index{---code-size<Value>}
-
-\end_inset
+-
+\begin_inset ERT
+status Collapsed
- Causes the linker to check if the code usage is within limits of the given
- value.
-\layout List
-\labelwidthstring 00.00.0000
+\layout Standard
+\backslash
+/
+\end_inset
-\series bold
----nostdincl
-\begin_inset LatexCommand \index{---nostdincl}
+-nostdincl
+\begin_inset LatexCommand \index{-\/-nostdincl}
\end_inset
\series bold
----nostdlib
-\begin_inset LatexCommand \index{---nostdlib}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-nostdlib
+\begin_inset LatexCommand \index{-\/-nostdlib}
\end_inset
\series default
- This will prevent the compiler from passing on the default library path
- to the linker.
+ 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
\series bold
----verbose
-\begin_inset LatexCommand \index{---verbose}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-verbose
+\begin_inset LatexCommand \index{-\/-verbose}
\end_inset
\series bold
----no-c-code-in-asm
-\begin_inset LatexCommand \index{---no-c-code-in-asm}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-no-c-code-in-asm
+\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
\end_inset
\series bold
----i-code-in-asm
-\begin_inset LatexCommand \index{---i-code-in-asm}
+-
+\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 helpfull for debugging the compiler itself.
+ Sounds like noise but is most helpful for debugging the compiler itself.
\layout List
\labelwidthstring 00.00.0000
\series bold
----less-pedantic
-\begin_inset LatexCommand \index{---less-pedantic}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-less-pedantic
+\begin_inset LatexCommand \index{-\/-less-pedantic}
\end_inset
\series bold
----print-search-dirs
-\begin_inset LatexCommand \index{---print-search-dirs}
+-
+\begin_inset ERT
+status Collapsed
-\end_inset
+\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-stdout
+\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}
+\begin_inset LatexCommand \index{Options intermediate dump}
\end_inset
-\begin_inset LatexCommand \index{Intermediate Dump Options}
+\begin_inset LatexCommand \index{Intermediate dump options}
\end_inset
\series bold
----dumpraw
-\begin_inset LatexCommand \index{---dumpraw}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpraw
+\begin_inset LatexCommand \index{-\/-dumpraw}
\end_inset
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}
+\begin_inset LatexCommand \index{Basic blocks}
\end_inset
\series bold
----dumpgcse
-\begin_inset LatexCommand \index{---dumpgcse}
+-
+\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}
+\begin_inset LatexCommand \index{Global subexpression elimination}
\end_inset
\series bold
----dumpdeadcode
-\begin_inset LatexCommand \index{---dumpdeadcode}
+-
+\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{deadcode elimination}
+\begin_inset LatexCommand \index{Dead-code elimination}
\end_inset
\series bold
----dumploop
-\begin_inset LatexCommand \index{---dumploop}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumploop
+\begin_inset LatexCommand \index{-\/-dumploop}
\end_inset
\size default
Will create a dump of iCode's, after loop optimizations
-\begin_inset LatexCommand \index{loop optimizations}
+\begin_inset LatexCommand \index{Loop optimization}
\end_inset
\series bold
----dumprange
-\begin_inset LatexCommand \index{---dumprange}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumprange
+\begin_inset LatexCommand \index{-\/-dumprange}
\end_inset
\size default
Will create a dump of iCode's, after live range analysis
-\begin_inset LatexCommand \index{live range analysis}
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
\series bold
----dumlrange
-\begin_inset LatexCommand \index{---dumlrange}
+-
+\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{life ranges}
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
\series bold
----dumpregassign
-\begin_inset LatexCommand \index{---dumpregassign}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpregassign
+\begin_inset LatexCommand \index{-\/-dumpregassign}
\end_inset
\series default
\bar default
Will create a dump of iCode's, after register assignment
-\begin_inset LatexCommand \index{register assignment}
+\begin_inset LatexCommand \index{Register assignment}
\end_inset
\series bold
----dumplrange
-\begin_inset LatexCommand \index{---dumplrange}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumplrange
+\begin_inset LatexCommand \index{-\/-dumplrange}
\end_inset
\series bold
----dumpall
-\begin_inset LatexCommand \index{---dumpall}
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-dumpall
+\begin_inset LatexCommand \index{-\/-dumpall}
\end_inset
\size default
\bar default
Will cause all the above mentioned dumps to be created.
+\layout Subsubsection
+
+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
+
+\newline
+
+\series bold
+c:
+\backslash
+sdcc
+\backslash
+bin
+\backslash
+sdcc.exe -
+\series default
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+\emph default
+-vc -
+\series default
+\emph on
+
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+
+\series bold
+\emph default
+-model-large -c $(InputPath)
\layout Subsection
Environment variables
\series default
SDCC installs a signal handler
-\begin_inset LatexCommand \index{ signal handler}
+\begin_inset LatexCommand \index{signal handler}
\end_inset
\series bold
-TMP
-\begin_inset LatexCommand \index{TMP}
-
-\end_inset
-
-,\SpecialChar ~
-TEMP
-\begin_inset LatexCommand \index{TEMP}
-
-\end_inset
-
-,\SpecialChar ~
+TMP,\SpecialChar ~
+TEMP,\SpecialChar ~
TMPDIR
-\begin_inset LatexCommand \index{TMPDIR}
+\begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
\end_inset
There are some more environment variables recognized by SDCC, but these
are solely used for debugging purposes.
- They can change or disappear very quickly, and will never be documentated.
+ They can change or disappear very quickly, and will never be documented.
\layout Subsection
MCS51/DS390 Storage Class
-\begin_inset LatexCommand \index{Storage Class}
+\begin_inset LatexCommand \index{Storage class}
\end_inset
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 extern
- RAM.
- This is the
-\series bold
-default
-\series default
- storage class for Large Memory model, e.g.:
-\newline
-
-\newline
-
-\family typewriter
-xdata unsigned char xduc;
-\layout Subsubsection
-
data
\begin_inset LatexCommand \index{data}
default
\series default
storage class for Small Memory model.
- Variables declared with this storage class will be allocated in the internal
- RAM, e.g.:
-\newline
+ Variables declared with this storage class will be allocated in the directly
+ addressable portion of the internal RAM of a 8051, e.g.:
+\layout Verse
-\newline
\family typewriter
-data int iramdata;
-\layout Subsubsection
-
-idata
-\begin_inset LatexCommand \index{idata}
-
-\end_inset
-
-
+data unsigned char test_data;
\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.:
-\newline
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
-\newline
\family typewriter
-idata int idi;
+75*00 01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+_test_data,#0x01
\layout Subsubsection
-bit
-\begin_inset LatexCommand \index{bit}
+xdata
+\begin_inset LatexCommand \index{xdata}
\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.:
-\newline
+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
-\newline
\family typewriter
-bit iFlag;
-\layout Subsubsection
+xdata unsigned char test_xdata;
+\layout Standard
+
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+90s00r00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+dptr,#_test_xdata
+\newline
+74\SpecialChar ~
+01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+a,#0x01
+\newline
+F0\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movx\SpecialChar ~
+@dptr,a
+\layout Subsubsection
+
+idata
+\begin_inset LatexCommand \index{idata}
+
+\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 unsigned char test_idata;
+\layout Standard
+
+Writing 0x01 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+78r00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+r0,#_test_idata
+\newline
+76\SpecialChar ~
+01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+@r0,#0x01
+\layout Subsubsection
+
+pdata
+\begin_inset LatexCommand \index{pdata}
+
+\end_inset
+
+
+\layout Standard
+
+Paged xdata access is currently not as straightforward as using the other
+ addressing modes of a 8051.
+ The following example writes 0x01 to the address pointed to.
+ Please note, pdata access physically accesses xdata memory.
+ The high byte of the address is determined by port P2 (or in case of some
+ 8051 variants by a separate Special Function Register).
+\layout Verse
+
+
+\family typewriter
+pdata unsigned char *test_pdata_ptr;
+\newline
+
+\newline
+void main()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+test_pdata_ptr = (pdata *)0xfe;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+*test_pdata_ptr = 1;
+\newline
+}
+\layout Standard
+
+Generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+75*01 FE\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ _test_pdata_ptr,#0xFE
+\newline
+78 FE\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ r0,#0xFE
+\newline
+74 01\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+ a,#0x01
+\newline
+F2\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movx @r0,a
+\layout Standard
+
+Be extremely carefull if you use pdata together with the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+ option.
+\layout Subsubsection
+
+code
+\begin_inset LatexCommand \index{code}
+
+\end_inset
+
+
+\layout Standard
+
+'Variables' declared with this storage class will be placed in the code
+ memory:
+\layout Verse
+
+
+\family typewriter
+code unsigned char test_code;
+\layout Standard
+
+Read access to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+90s00r6F\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dptr,#_test_code
+\newline
+E4\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+clr a
+\newline
+93\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+movc a,@a+dptr
+\layout Subsubsection
+
+bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+
+\layout Standard
+
+This is a data-type and a storage class specifier.
+ When a variable is declared as a bit, it is allocated into the bit addressable
+ memory of 8051, e.g.:
+\layout Verse
+
+
+\family typewriter
+bit test_bit;
+\layout Standard
+
+Writing 1 to this variable generates the assembly code:
+\layout Verse
+
+
+\family typewriter
+D2*00\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+setb\SpecialChar ~
+_test_bit
+\layout Subsubsection
sfr
\begin_inset LatexCommand \index{sfr}
\emph default
signifies both a data-type and storage class, they are used to describe
the special function registers and special bit variables of a 8051, eg:
-\newline
+\layout Verse
-\newline
\family typewriter
-sfr at 0x80 P0; /* special function register P0 at location 0x80 */
+sfr at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ 0x80 P0;\SpecialChar ~
+ /* special function register P0 at location 0x80 */
\newline
sbit at 0xd7 CY; /* CY (Carry Flag
+\begin_inset LatexCommand \index{Flags}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{Carry flag}
\end_inset
) */
-\layout Subsection
+\layout Subsubsection
Pointers
\begin_inset LatexCommand \index{Pointers}
\end_inset
-
+ to MCS51/DS390 specific memory spaces
\layout Standard
SDCC allows (via language extensions) pointers to explicitly point to any
of the memory spaces
-\begin_inset LatexCommand \index{memory spaces}
+\begin_inset LatexCommand \index{Memory model}
\end_inset
\newline
Pointer declaration examples:
-\newline
+\layout Verse
-\size small
+\family typewriter
+/* pointer physically in internal ram pointing to object in external ram
+ */
+\newline
+xdata unsigned char * data p;
\newline
-\family typewriter
-\size default
-/* pointer physically in xternal ram pointing to object in internal ram
+\newline
+/* pointer physically in external ram pointing to object in internal ram
*/
\newline
data unsigned char * xdata p;
\newline
\newline
-/* the folowing is a generic pointer physically located in xdata space */
+/* the following is a generic pointer physically located in xdata space
+ */
\newline
char * xdata p;
-\family default
-\size small
-
-\newline
-
-\newline
+\layout Standard
-\size default
Well you get the idea.
\newline
generic
\emph default
pointers.
- These are useful for developing reusable library routines.
+ 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 Variables}
+Absolute Addressing
+\begin_inset LatexCommand \index{Absolute addressing}
\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
+Data items can be assigned an absolute address with the
\emph on
-static
-\begin_inset LatexCommand \index{static}
+at
+\begin_inset LatexCommand \index{at}
\end_inset
-
+ <address>
\emph default
- so by default functions are non-reentrant
-\begin_inset LatexCommand \index{non-reentrant}
+ keyword, in addition to a storage class, e.g.:
+\layout Verse
-\end_inset
-.
-\newline
-
-\newline
-They can be placed on the stack
-\begin_inset LatexCommand \index{stack}
+\family typewriter
+xdata
+\begin_inset LatexCommand \index{xdata}
\end_inset
- either by using the
-\emph on
- ---stack-auto
-\begin_inset LatexCommand \index{--stack-auto}
+ at
+\begin_inset LatexCommand \index{at}
\end_inset
+ 0x7ffe unsigned int chksum;
+\layout Standard
-\emph default
- option or by using the
-\emph on
-reentrant
-\begin_inset LatexCommand \index{reentrant}
+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}
-\emph default
- keyword in the function declaration, e.g.:
-\newline
-
-\size small
+\end_inset
-\newline
+) and (.map
+\begin_inset LatexCommand \index{.map}
-\family typewriter
-\size default
-unsigned char foo(char i) reentrant
-\newline
-{
-\newline
-...
-
-\newline
-}
-\newline
+\end_inset
-\family default
+) are good places to look for such overlaps.
+\layout Standard
-\newline
-Since stack space on 8051 is limited, the
-\emph on
-reentrant
-\emph default
-keyword or the
+In case of memory mapped I/O devices the keyword
\emph on
- ---stack-auto
+volatile
\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
+ should be used to tell the compiler that accesses might not be optimized
+ away:
+\layout Verse
-\newline
-Local variables can be assigned storage classes and absolute
-\begin_inset LatexCommand \index{absolute}
-
-\end_inset
-
- addresses, e.g.:
-\newline
-
-\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 ~
-...
-
-\newline
-}
-\newline
+volatile
+\begin_inset LatexCommand \index{volatile}
-\newline
+\end_inset
-\family default
-In the above example the variable
-\emph on
-i
-\emph default
- will be allocated in the external ram,
-\emph on
-bvar
-\emph default
- in bit addressable space and
-\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
+ xdata
+\begin_inset LatexCommand \index{xdata}
-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
-\begin_inset LatexCommand \index{Overlaying}
+ at
+\begin_inset LatexCommand \index{at}
\end_inset
-
+ 0x8000 unsigned char PORTA_8255;
\layout Standard
-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
-\begin_inset LatexCommand \index{memory model}
-
-\end_inset
-
- is small.
+Absolute address can be specified for variables in all storage classes,
+ e.g.:
+\layout Verse
-\emph default
- If an explicit storage class 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}
+\family typewriter
+bit
+\begin_inset LatexCommand \index{bit}
\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}
+ at
+\begin_inset LatexCommand \index{at}
\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.
+ 0x02 bvar;
\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}
+The above example will allocate the variable at offset 0x02 in the bit-addressab
+le space.
+ There is no real advantage to assigning absolute addresses to variables
+ in this manner, unless you want strict control over all the variables allocated.
+ One possible use would be to write hardware portable code.
+ For example, if you have a routine that uses one or more of the microcontroller
+ I/O pins, and such pins are different for two different hardwares, you
+ can declare the I/O pins in your routine using:
+\layout Verse
-\end_inset
- will NOT be overlayed since these are implemented using external functions,
- e.g.:
+\family typewriter
+extern volatile bit SDI;
\newline
-
+extern volatile bit SCLK;
\newline
-
-\family typewriter
-#pragma SAVE
+extern volatile bit CPOL;
\newline
-#pragma NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
-
-\end_inset
-
\newline
-void set_error(unsigned char errcd)
+void DS1306_put(unsigned char value)
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-P3 = errcd;
-\newline
-}
-\newline
-#pragma RESTORE
+unsigned char mask=0x80;
\newline
\newline
-void some_isr () interrupt
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
-
- 2 using
-\begin_inset LatexCommand \index{using}
-
-\end_inset
-
- 1
+\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 ~
-set_error(10);
+\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
-\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
-
-Interrupt Service Routines
-\begin_inset LatexCommand \index{Interrupt Service Routines}
-
-\end_inset
+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
-SDCC allows interrupt service routines to be coded in C, with some extended
- keywords.
-\newline
+Similarly, for the second hardware you would use
+\layout Verse
-\newline
\family typewriter
-void timer_isr (void) interrupt 2 using 1
-\newline
-{
-\newline
-..
-
+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
-\newline
+and you can use the same hardware dependent routine without changes, as
+ for example in a library.
+ This is somehow similar to sbit, but only one absolute address has to be
+ specified in the whole project.
+\layout Subsection
-\family default
-The number following the
-\emph on
-interrupt
-\begin_inset LatexCommand \index{interrupt}
+Parameters
+\begin_inset LatexCommand \index{Parameters}
\end_inset
-
-\emph default
- keyword is the interrupt number this routine will service.
- The compiler will insert a call to this routine in the interrupt vector
- table for the interrupt number specified.
- The
-\emph on
-using
-\emph default
- keyword is used to tell the compiler to use the specified register bank
- (8051 specific) when generating code for this function.
- Note that when some function is called from an interrupt service routine
- it should be preceded by a #pragma\SpecialChar ~
-NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+ & Local Variables
+\begin_inset LatexCommand \index{Local variable}
\end_inset
- 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
-\begin_inset LatexCommand \index{---stack-auto}
-
-\end_inset
+\layout Standard
-\emph default
- option and the source file will need to be compiled using the
+Automatic (local) variables and parameters to functions can either be placed
+ on the stack or in data-space.
+ The default action of the compiler is to place these variables in the internal
+ RAM (for small model) or external RAM (for large model).
+ This in fact makes them
\emph on
----int-long-ren
-\emph default
-t
-\begin_inset LatexCommand \index{---int-long-rent}
+static
+\begin_inset LatexCommand \index{static}
\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 are listed below.
- SDCC will automatically adjust the interrupt vector table
-\begin_inset LatexCommand \index{ interrupt vector table}
+ so by default functions are non-reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
- to the maximum interrupt number specified.
+.
\newline
-\layout Standard
-
-
-\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
-
-\layout Standard
+\newline
+They can be placed on the stack
+\begin_inset LatexCommand \index{stack}
-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
+ either by using the
+\emph on
+ -
+\begin_inset ERT
+status Collapsed
\layout Standard
-Vector Address
+\backslash
+/
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\layout Standard
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
-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
+\emph default
+ option or by using the
+\emph on
+reentrant
+\begin_inset LatexCommand \index{reentrant}
-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
+\emph default
+ keyword in the function declaration, e.g.:
+\layout Verse
-Timer 0
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+\family typewriter
+unsigned char foo(char i) reentrant
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
\layout Standard
-0x000B
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+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
-2
+\backslash
+/
\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
+-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
-\layout Standard
+\newline
+Local variables can be assigned storage classes and absolute
+\begin_inset LatexCommand \index{Absolute addressing}
-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
+ addresses, e.g.:
+\layout Verse
-\layout Standard
-
-Timer 1
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+\family typewriter
+unsigned char foo()
+\newline
+{
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+xdata unsigned char i;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+bit bvar;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+data at 0x31 unsigned char j;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+}
\layout Standard
-0x001B
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+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
-4
+\backslash
+/
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+-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
-Serial
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\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
-0x0023
-\end_inset
-</cell>
-</row>
-</lyxtabular>
+Overlaying
+\begin_inset LatexCommand \label{sub:Overlaying}
\end_inset
-\newline
-
-\newline
-If the interrupt service routine is defined without
-\emph on
-using
-\begin_inset LatexCommand \index{using}
+\begin_inset LatexCommand \index{Overlaying}
\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
+For non-reentrant
+\begin_inset LatexCommand \index{reentrant}
-\shape italic
-<TODO: this isn't implemented at all!>
-\shape default
-
-\newline
+\end_inset
-\newline
-A special keyword may be associated with a function declaring it as
+ 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
-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
+no other function calls and the function is non-reentrant and the memory
+ model
+\begin_inset LatexCommand \index{Memory model}
-\size small
+\end_inset
-\newline
+ is small.
-\family typewriter
-\size default
-int foo () critical
-\newline
-{
-\newline
-...
-
-\newline
-...
-
-\newline
-}
-\newline
+\emph default
+ If an explicit storage class
+\begin_inset LatexCommand \index{Storage class}
-\family default
+\end_inset
-\newline
-The critical attribute maybe used with other attributes like
-\emph on
-reentrant.
-\layout Subsection
+ is specified for a local variable, it will NOT be overlayed.
+\layout Standard
-Naked Functions
-\begin_inset LatexCommand \index{Naked Functions}
+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
-A special keyword may be associated with a function declaring it as
-\emph on
-_naked
-\begin_inset LatexCommand \index{\_naked}
+Also note that the compiler does not do any processing of inline
+\begin_inset LatexCommand \index{inline}
\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}
+ 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
- and epilogue
-\begin_inset LatexCommand \index{function epilogue}
+ or division
+\begin_inset LatexCommand \index{Division}
\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:
-\newline
+ will NOT be overlayed since these are implemented using external functions,
+ e.g.:
+\layout Verse
-\newline
\family typewriter
-data unsigned char counter;
+#pragma SAVE
\newline
-void simpleInterrupt(void) interrupt
-\begin_inset LatexCommand \index{interrupt}
+#pragma NOOVERLAY
+\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
\end_inset
- 1
+
+\newline
+void set_error(unsigned char errcd)
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-counter++;
+P3 = errcd;
\newline
-}
+}
+\newline
+#pragma RESTORE
\newline
\newline
-void nakedInterrupt(void) interrupt 2 _naked
+void some_isr () interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ 2
\newline
{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
+...
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
+set_error(10);
\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;
+...
+
\newline
}
-\family default
+\layout Standard
-\newline
+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
-\newline
-For an 8051 target, the generated simpleInterrupt looks like:
-\newline
+Interrupt Service Routines
+\layout Standard
+
+SDCC allows interrupt service routines to be coded in C, with some extended
+ keywords.
+\layout Verse
-\newline
\family typewriter
-_simpleIterrupt:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-acc
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dpl
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-dph
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-push\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-psw,#0x00
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\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
+void timer_isr (void) interrupt 1 using 1
\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
-\family default
+}
+\layout Standard
-\newline
+The optional number following the
+\emph on
+interrupt
+\begin_inset LatexCommand \index{interrupt}
-\newline
-whereas nakedInterrupt looks like:
-\newline
+\end_inset
-\newline
-\family typewriter
-_nakedInterrupt:
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-inc\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-_counter
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-reti\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-; MUST explicitly include ret(i) in _naked function.
-\family default
+\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}
-\newline
+\end_inset
-\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
+ 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
-Functions using private banks
-\begin_inset LatexCommand \index{banks}
+\begin_inset LatexCommand \index{volatile}
\end_inset
-
+.
+
\layout Standard
-The
-\emph on
-using
-\begin_inset LatexCommand \index{using}
+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}
-\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
+
+ & 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
-\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
+\backslash
+/
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
\emph default
- attribute will have no effect on the generated code for a
+ option and the source file will need to be compiled using the
\emph on
-non-interrupt
-\emph default
- function (but may occasionally be useful anyway
-\begin_inset Foot
-collapsed true
+-
+\begin_inset ERT
+status Collapsed
\layout Standard
-possible exception: if a function is called ONLY from 'interrupt' functions
- using a particular bank, it can be declared with the same 'using' attribute
- as the calling 'interrupt' functions.
- For instance, if you have several ISRs using bank one, and all of them
- call memcpy(), it might make sense to create a specialized version of memcpy()
- 'using 1', since this would prevent the ISR from having to save bank zero
- to the stack on entry and switch to bank zero before calling the function
+\backslash
+/
\end_inset
-).
-\newline
+-int-long-ren
+\emph default
+t
+\begin_inset LatexCommand \index{-\/-int-long-rent}
-\emph on
-(pending: I don't think this has been done yet)
+\end_inset
+
+ compiler option.
\layout Standard
-An
+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
-interrupt
+main
\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}
+.
+\layout Standard
-\end_inset
+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
- 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
+\align center
-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
+\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
-Absolute Addressing
-\begin_inset LatexCommand \index{Absolute Addressing}
+\layout Standard
+Interrupt #
\end_inset
-
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
\layout Standard
-Data items can be assigned an absolute address with the
-\emph on
-at
-\begin_inset LatexCommand \index{at}
-
+Description
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- <address>
-\emph default
- keyword, in addition to a storage class, e.g.:
-\newline
+\layout Standard
-\newline
+Vector Address
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-xdata
-\begin_inset LatexCommand \index{xdata}
+\layout Standard
+0
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- at
-\begin_inset LatexCommand \index{at}
+\layout Standard
+External 0
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- 0x8000 unsigned char PORTA_8255 ;
-\newline
+\layout Standard
-\family default
+0x0003
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\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
-\begin_inset LatexCommand \index{.lst}
+\layout Standard
+1
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-) and the linker output files (.rst
-\begin_inset LatexCommand \index{.rst}
+\layout Standard
+Timer 0
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-) and (.map
-\begin_inset LatexCommand \index{.map}
+\layout Standard
+0x000B
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-) are a good places to look for such overlaps.
-\newline
-
-\newline
-Absolute address can be specified for variables in all storage classes,
- e.g.:
-\newline
+\layout Standard
-\newline
+2
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-bit
-\begin_inset LatexCommand \index{bit}
+\layout Standard
+External 1
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- at
-\begin_inset LatexCommand \index{at}
+\layout Standard
+0x0013
\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
- 0x02 bvar;
-\newline
-
-\newline
+\layout Standard
-\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
+3
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-Startup Code
-\begin_inset LatexCommand \index{Startup Code}
+\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
-The compiler inserts a call to the C routine
-\emph on
-_sdcc_external_startup()
-\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
+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
-\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
+Serial
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Inline Assembler Code
-\begin_inset LatexCommand \index{Inline Assembler Code}
+\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
-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
+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
-nnnnn$
+using
+\begin_inset LatexCommand \index{using}
+
+\end_inset
+
+
\emph default
- where nnnn is a number less than 100 (which implies a limit of utmost 100
- inline assembler labels
+ 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
-per function
+a, b & dptr
\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
-\begin_inset LatexCommand \index{--peep-asm}
+ 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
-\end_inset
+Calling other functions from an interrupt service routine is not recommended,
+ avoid it if possible.
+\newline
+For some pitfalls see section
+\begin_inset LatexCommand \ref{sub:Overlaying}
+\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}
+about Overlaying and section
+\begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
\end_inset
-.
- This might cause some unexpected changes in the inline assembler code.
- Please go throught the peephole optimizer rules defined in file
-\emph on
-SDCCpeeph.def
-\emph default
- carefully before using this option.
+about Functions using private banks.
\newline
+\layout Subsection
+
+Critical Functions
+\layout Standard
+
+
+\shape italic
+<TODO: this isn't implemented at all!>
+\shape default
+
\newline
-\family typewriter
-_asm
-\begin_inset LatexCommand \index{\_asm}
+\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
-\end_inset
-
+\family typewriter
+int foo () critical
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-mov\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b,#10
-\newline
-00001$:
+...
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-djnz\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-b,00001$
+...
+
\newline
-_endasm
-\begin_inset LatexCommand \index{\_endasm}
+}
+\layout Standard
+
+The critical attribute maybe used with other attributes like
+\emph on
+reentrant.
+\layout Subsection
+
+Naked Functions
+\begin_inset LatexCommand \label{sub:Naked-Functions}
\end_inset
- ;
-\family default
-\size small
-\newline
+\begin_inset LatexCommand \index{Naked functions}
-\newline
+\end_inset
-\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.
+
+\layout Standard
+
+A special keyword may be associated with a function declaring it as
+\emph on
+_naked
+\begin_inset LatexCommand \index{\_naked}
+
+\end_inset
+
+.
-\newline
+\emph default
+The
+\emph on
+_naked
+\emph default
+ function modifier attribute prevents the compiler from generating prologue
+\begin_inset LatexCommand \index{function prologue}
-\newline
-Inline assembler code cannot reference any C-Labels, however it can reference
- labels
-\begin_inset LatexCommand \index{Labels}
+\end_inset
+
+ and epilogue
+\begin_inset LatexCommand \index{function epilogue}
\end_inset
- defined by the inline assembler, e.g.:
+ 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
\newline
+void simpleInterrupt(void) interrupt
+\begin_inset LatexCommand \index{interrupt}
-\family typewriter
-foo() {
+\end_inset
+
+ 1
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-/* some c code */
+counter++;
+\newline
+}
+\newline
+
+\newline
+void nakedInterrupt(void) interrupt 2 _naked
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
+_asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-; some assembler code
-\newline
-\SpecialChar ~
-\SpecialChar ~
+inc\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-ljmp $0003
+_counter
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_endasm;
-\newline
\SpecialChar ~
\SpecialChar ~
+reti\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-/* some more c code */
-\newline
-clabel:\SpecialChar ~
\SpecialChar ~
-/* inline assembler cannot reference this label */
+; MUST explicitly include ret or reti in _naked function.
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_asm
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
+
+\end_inset
+
+;
+\newline
+}
+\layout Standard
+
+For an 8051 target, the generated simpleInterrupt looks like:
+\layout Verse
+
+
+\family typewriter
+_simpleInterrupt:
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-$0003: ;label (can be reference by inline assembler only)
-\newline
-\SpecialChar ~
+push\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-_endasm ;
+acc
\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-/* some more c code */
-\newline
-}
-\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)
-\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 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
-
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
\newline
-_mulsint.c - signed 16 bit multiplication (calls _muluint)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
\newline
-_muluint.c - unsigned 16 bit multiplication
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw
\newline
-_divsint.c - signed 16 bit division (calls _divuint)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw,#0x00
\newline
-_divuint.c - unsigned 16 bit division
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter
\newline
-_modsint.c - signed 16 bit modulus (call _moduint)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+psw
\newline
-_moduint.c - unsigned 16 bit modulus
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dph
\newline
-_mulslong.c - signed 32 bit multiplication (calls _mululong)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
\newline
-_mululong.c - unsigned32 bit multiplication
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b
\newline
-_divslong.c - signed 32 division (calls _divulong)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+acc
\newline
-_divulong.c - unsigned 32 division
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+reti
+\layout Standard
+
+whereas nakedInterrupt looks like:
+\layout Verse
+
+
+\family typewriter
+_nakedInterrupt:
\newline
-_modslong.c - signed 32 bit modulus (calls _modulong)
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+inc\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_counter
\newline
-_modulong.c - unsigned 32 bit modulus
-\size footnotesize
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+reti\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+; MUST explicitly include ret or reti in _naked function.
+\layout Standard
-\newline
+The #pragma directive EXCLUDE
+\begin_inset LatexCommand \index{\#pragma EXCLUDE}
-\newline
+\end_inset
-\size default
-Since they are compiled as
-\emph on
-non-reentrant
-\emph default
+ also allows to reduce pushing & popping the registers.
+\layout Standard
-\begin_inset LatexCommand \index{reentrant}
+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 \label{sub:Functions-using-private-banks}
\end_inset
-\begin_inset LatexCommand \index{non-reentrant}
+\begin_inset LatexCommand \index{bank}
\end_inset
-, interrupt
-\begin_inset LatexCommand \index{interrupt}
-\end_inset
+\layout Standard
- 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
+The
\emph on
----stack-auto
-\begin_inset LatexCommand \index{---stack-auto}
+using
+\begin_inset LatexCommand \index{using}
\end_inset
\emph default
- option, after which the source program will have to be compiled with
+ attribute (which tells the compiler to use a register bank other than the
+ default bank zero) should only be applied to
\emph on
----int-long-rent
-\begin_inset LatexCommand \index{---int-long-rent}
+interrupt
+\begin_inset LatexCommand \index{interrupt}
\end_inset
\emph default
- option.
-\layout Subsection
-
-Floating Point Support
-\begin_inset LatexCommand \index{Floating Point Support}
-
-\end_inset
+ 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
-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
+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: tabularise this>
+(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}
-\newline
+\end_inset
-\newline
-_fsadd.c - add floating point numbers
-\newline
-_fssub.c - subtract floating point numbers
-\newline
-_fsdiv.c - divide floating point numbers
-\newline
-_fsmul.c - multiply floating point numbers
-\newline
-_fs2uchar.c - convert floating point to unsigned char
-\newline
-_fs2char.c - convert floating point to signed char
-\newline
-_fs2uint.c - convert floating point to unsigned int
-\newline
-_fs2int.c - convert floating point to signed int
-\newline
-_fs2ulong.c - convert floating point to unsigned long
-\newline
-_fs2long.c - convert floating point to signed long
-\newline
-_uchar2fs.c - convert unsigned char to floating point
-\newline
-_char2fs.c - convert char to floating point number
-\newline
-_uint2fs.c - convert unsigned int to floating point
-\newline
-_int2fs.c - convert int to floating point numbers
-\newline
-_ulong2fs.c - convert unsigned long to floating point number
-\newline
-_long2fs.c - convert long to floating point number
-\size footnotesize
-
-\newline
-
-\newline
-
-\size default
-Note if all these routines are used simultaneously the data space might
- overflow.
- For serious floating point usage it is strongly recommended that the large
- model be used.
-\layout Subsection
-
-MCS51 Memory Models
-\begin_inset LatexCommand \index{Memory Models}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{MCS51 Memory Models}
-
-\end_inset
-
-
-\layout Standard
-
-SDCC allows two memory models for MCS51 code, small and large.
- Modules compiled with different memory models should
+ can interrupt low-priority ones on the 8051 and friends, this means that
+ if a high-priority ISR
\emph on
-never
+using
\emph default
- be combined together or the results would be unpredictable.
- The library routines supplied with the compiler are compiled as both small
- and large.
- The compiled library modules are contained in seperate directories as small
- and large so that you can link to either set.
-
-\layout Standard
-
-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.
+ 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
-Judicious usage of the processor specific storage classes
-\begin_inset LatexCommand \index{storage classes}
-
-\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 recommdended that the small model
- be used unless absolutely required.
+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
-DS390 Memory Models
-\begin_inset LatexCommand \index{Memory Models}
+Startup Code
+\begin_inset LatexCommand \label{sub:Startup-Code}
\end_inset
-\begin_inset LatexCommand \index{DS390 Memory Models}
+\begin_inset LatexCommand \index{Startup code}
\end_inset
\layout Standard
-The only model supported is Flat 24
-\begin_inset LatexCommand \index{Flat 24}
+The compiler inserts a call to the C routine
+\emph on
+_sdcc_external_startup()
+\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
\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
+\series bold
\emph default
- switch.
-\newline
+\series default
+at the start of the CODE area.
+ This routine is in the runtime library
+\begin_inset LatexCommand \index{Runtime library}
-\newline
-Note that the compiler does not generate any code to place the processor
- into 24 bitmode (although
+\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.
+ Otherwise static & global variables will be initialized before the function
+ main is invoked.
+ You could add a
\emph on
-tinibios
+_sdcc_external_startup()
\emph default
- in the ds390 libraries will do that for you).
- If you don't use
+ 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.
+ See also the compiler option
\emph on
-tinibios
-\emph default
+-
+\begin_inset ERT
+status Collapsed
-\begin_inset LatexCommand \index{tinibios}
+\layout Standard
+\backslash
+/
\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
----model-large
+-no-xinit
\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
- ---*-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
+opt
\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}
+\begin_inset LatexCommand \index{-\/-no-xinit-opt}
\end_inset
.
-\layout Itemize
-
-SDCC
-\begin_inset LatexCommand \index{SDCC}
-
-\end_inset
-
- - this Symbol is always defined.
-\layout Itemize
-
-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 - depending on the model used (e.g.: -mds390)
-\layout Itemize
-
-__mcs51
-\begin_inset LatexCommand \index{\_\_mcs51}
-
-\end_inset
-
- or __ds390
-\begin_inset LatexCommand \index{\_\_ds390}
-
-\end_inset
+\layout Subsection
- or __z80
-\begin_inset LatexCommand \index{\_\_z80}
+Inline Assembler Code
+\begin_inset LatexCommand \index{Assembler routines}
\end_inset
-, etc - depending on the model used (e.g.
- -mz80)
-\layout Itemize
-
-SDCC_STACK_AUTO
-\begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
-\end_inset
+\layout Standard
- - this symbol is defined when
+SDCC allows the use of in-line assembler with a few restriction as regards
+ labels.
+ All labels defined within inline assembler code
\emph on
----stack-auto
+has to be
\emph default
- option is used.
-\layout Itemize
-
-SDCC_MODEL_SMALL
-\begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
-
-\end_inset
-
- - when
+ of the form
\emph on
----model-small
+nnnnn$
\emph default
- is used.
-\layout Itemize
-
-SDCC_MODEL_LARGE
-\begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
-
-\end_inset
-
- - when
+ where nnnn is a number less than 100 (which implies a limit of utmost 100
+ inline assembler labels
\emph on
----model-large
+per function
\emph default
- is used.
-\layout Itemize
+\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 -
+\begin_inset ERT
+status Collapsed
-SDCC_USE_XSTACK
-\begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
+\layout Standard
+\backslash
+/
\end_inset
- - when
+-
\emph on
----xstack
-\emph default
- option is used.
-\layout Itemize
-
-SDCC_STACK_TENBIT
-\begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
+peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
\end_inset
- - when
-\emph on
--mds390
-\emph default
- is used
-\layout Itemize
-SDCC_MODEL_FLAT24
-\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
+\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
- - when
+.
+ This might cause some unexpected changes in the inline assembler code.
+ Please go through the peephole optimizer rules defined in file
\emph on
--mds390
+SDCCpeeph.def
\emph default
- is used
-\layout Section
+ carefully before using this option.
+\layout Verse
-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{Sub-expression Elimination}
+\family typewriter
+_asm
+\begin_inset LatexCommand \index{\_asm}
\end_inset
-
-\layout Standard
-
-The compiler does local and global common subexpression elimination, e.g.:
\newline
-
-\newline
-
-\family typewriter
-i = x + y + 1;
-\newline
-j = x + y;
-\family default
-
-\newline
-
-\newline
-will be translated to
-\newline
-
-\newline
-
-\family typewriter
-iTemp = x + y
-\newline
-i = iTemp + 1
-\newline
-j = iTemp
-\newline
-
-\family default
-
-\newline
-Some subexpressions are not as obvious as the above example, e.g.:
-\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b,#10
\newline
-
-\family typewriter
-a->b[i].c = 10;
+00001$:
\newline
-a->b[i].d = 11;
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+djnz\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+b,00001$
\newline
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
-\newline
-In this case the address arithmetic a->b[i] will be computed only once;
- the equivalent code in C would be.
-\newline
+\end_inset
-\newline
+ ;
+\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
-iTemp = a->b[i];
-\newline
-iTemp.c = 10;
-\newline
-iTemp.d = 11;
+_asm ...
+ _endasm;
\family default
-
+ keyword pair.
+
\newline
\newline
-The compiler will try to keep these temporary variables in registers.
-\layout Subsubsection
-
-Dead-Code Elimination
-\begin_inset LatexCommand \index{Dead-Code Elimination}
+Inline assembler code cannot reference any C-Labels, however it can reference
+ labels
+\begin_inset LatexCommand \index{Labels}
\end_inset
-
-\layout Standard
+ defined by the inline assembler, e.g.:
+\layout Verse
\family typewriter
-int global;
-\newline
-void f () {
+foo() {
\newline
\SpecialChar ~
\SpecialChar ~
-int i;
-\newline
\SpecialChar ~
\SpecialChar ~
-i = 1; \SpecialChar ~
-/* dead store */
+/* some c code */
\newline
\SpecialChar ~
\SpecialChar ~
-global = 1;\SpecialChar ~
-/* dead store */
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 2;
+_asm
\newline
\SpecialChar ~
\SpecialChar ~
-return;
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 3;\SpecialChar ~
-/* unreachable */
-\newline
-}
-\family default
-
-\newline
-
-\newline
-will be changed to
-\newline
-
-\newline
-
-\family typewriter
-int global; void f ()
-\newline
-{
-\newline
\SpecialChar ~
\SpecialChar ~
-global = 2;
+; some assembler code
\newline
\SpecialChar ~
\SpecialChar ~
-return;
-\newline
-}
-\layout Subsubsection
-
-Copy-Propagation
-\begin_inset LatexCommand \index{Copy-Propagation}
-
-\end_inset
-
-
-\layout Standard
-
-
-\family typewriter
-int f() {
-\newline
\SpecialChar ~
\SpecialChar ~
-int i, j;
-\newline
\SpecialChar ~
\SpecialChar ~
-i = 10;
+ljmp $0003
\newline
\SpecialChar ~
\SpecialChar ~
-j = i;
-\newline
\SpecialChar ~
\SpecialChar ~
-return j;
-\newline
-}
-\family default
-
-\newline
-
-\newline
-will be changed to
+_endasm;
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some more c code */
\newline
-
-\family typewriter
-int f() {
+clabel:\SpecialChar ~
+\SpecialChar ~
+/* inline assembler cannot reference this label */
\newline
\SpecialChar ~
- \SpecialChar ~
- int i,j;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_asm
\newline
\SpecialChar ~
- \SpecialChar ~
- i = 10;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+$0003: ;label (can be reference by inline assembler only)
\newline
\SpecialChar ~
- \SpecialChar ~
- j = 10;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+_endasm ;
\newline
\SpecialChar ~
- \SpecialChar ~
- return 10;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* some more c code */
\newline
}
-\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 Standard
+
+An example acessing a C variable is in section
+\begin_inset LatexCommand \ref{sub:Naked-Functions}
+
+\end_inset
+
+.
+\layout Subsection
+
+Interfacing with Assembler Code
+\begin_inset LatexCommand \index{Assembler routines}
+
+\end_inset
-\newline
-\family default
-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 Optimizations}
+Global Registers used for Parameter Passing
+\begin_inset LatexCommand \index{Parameter passing}
\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 allocator}
+The compiler always uses the global registers
+\emph on
+DPL, DPH
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
\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}
+, B
+\begin_inset LatexCommand \index{B (register)}
\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 ---noinduction
- option) or for a given function only using #pragma\SpecialChar ~
-NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+
+\emph default
+and
+\emph on
+ ACC
+\begin_inset LatexCommand \index{ACC}
\end_inset
-.
-\newline
-\newline
-Loop Invariant:
-\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
-\newline
+\layout Standard
-\family typewriter
-for (i = 0 ; i < 100 ; i ++)
-\newline
- \SpecialChar ~
- \SpecialChar ~
-f += k + l;
-\family default
+\backslash
+/
+\end_inset
-\newline
+-stack-auto is used) or in data / xdata memory (depending on the memory
+ model).
+
+\layout Subsubsection
-\newline
-changed to
-\newline
+Assembler Routine(non-reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+)
+\begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
+
+\end_inset
+
+
+\layout Standard
+
+In the following example the function c_func calls an assembler routine
+ asm_func, which takes two parameters.
+\layout Verse
-\newline
\family typewriter
-itemp = k + l;
+extern int asm_func(unsigned char, unsigned char);
\newline
-for (i = 0; i < 100; i++)
+
+\newline
+int c_func (unsigned char i, unsigned char j)
+\newline
+{
\newline
\SpecialChar ~
\SpecialChar ~
-f += itemp;
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+return asm_func(i,j);
+\newline
+}
\newline
\newline
-As mentioned previously some loop invariants are not as apparent, all static
- address computations are also moved out of the loop.
+int main()
\newline
-
+{
\newline
-Strength Reduction
-\begin_inset LatexCommand \index{Strength Reduction}
-
-\end_inset
-
-, this optimization substitutes an expression by a cheaper expression:
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return c_func(10,9);
\newline
+}
+\layout Standard
+
+The corresponding assembler function is:
+\layout Verse
-\newline
\family typewriter
-for (i=0;i < 100; i++)
+.globl _asm_func_PARM_2
\newline
\SpecialChar ~
\SpecialChar ~
-ar[i*5] = i*3;
-\family default
-
-\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.globl _asm_func
\newline
-changed to
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area OSEG
\newline
-
+_asm_func_PARM_2:
\newline
-
-\family typewriter
-itemp1 = 0;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.ds 1
\newline
-itemp2 = 0;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+.area CSEG
\newline
-for (i=0;i< 100;i++) {
+_asm_func:
\newline
- \SpecialChar ~
- \SpecialChar ~
-ar[itemp1] = itemp2;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,dpl
\newline
- \SpecialChar ~
- \SpecialChar ~
-itemp1 += 5;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,_asm_func_PARM_2
\newline
- \SpecialChar ~
- \SpecialChar ~
-itemp2 += 3;
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dpl,a
\newline
-}
-\family default
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+dpl
+\begin_inset LatexCommand \index{DPTR, DPH, DPL}
-\newline
+\end_inset
+,#0x00
\newline
-The more expensive multiplication
-\begin_inset LatexCommand \index{multiplication}
+\SpecialChar ~
+\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
- is changed to a less expensive addition.
-\layout Subsubsection
+dpl
+\begin_inset Quotes erd
+\end_inset
-Loop Reversing
-\begin_inset LatexCommand \index{Loop Reversing}
+ 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
-\layout Standard
+b,dptr
+\begin_inset Quotes erd
+\end_inset
-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
+ for three bytes and
\begin_inset Quotes eld
\end_inset
-decrement and jump if not zero
+acc,b,dptr
\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
+ for four bytes, the variable name for the second parameter will be _<function_n
+ame>_PARM_2.
+\newline
-The 'for' loop is of the form
+\newline
+Assemble the assembler routine with the following command:
\newline
\newline
-\family typewriter
-for (<symbol> = <expression> ; <sym> [< | <=] <expression> ; [<sym>++ |
- <sym> += 1])
+\family sans
+\series bold
+asx8051 -losg asmfunc.asm
\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-<for body>
-\layout Itemize
-The <for body> does not contain
-\begin_inset Quotes eld
-\end_inset
+\newline
-continue
-\begin_inset Quotes erd
-\end_inset
+\family default
+\series default
+Then compile and link the assembler routine to the C source file with the
+ following command:
+\newline
- or 'break
-\begin_inset Quotes erd
-\end_inset
+\newline
-.
-\layout Itemize
+\family sans
+\series bold
+sdcc cfunc.c asmfunc.rel
+\layout Subsubsection
-All goto's are contained within the loop.
-\layout Itemize
+Assembler Routine(reentrant
+\begin_inset LatexCommand \index{reentrant}
-No function calls within the loop.
-\layout Itemize
+\end_inset
-The loop control variable <sym> is not assigned any value within the loop
-\layout Itemize
+)
+\begin_inset LatexCommand \index{Assembler routines (reentrant)}
-The loop control variable does NOT participate in any arithmetic operation
- within the loop.
-\layout Itemize
+\end_inset
-There are NO switch statements in the loop.
-\layout Subsubsection
-Algebraic Simplifications
\layout Standard
-SDCC does numerous algebraic simplifications, the following is a small sub-set
- of these optimizations.
-\newline
+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
-\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;
+extern int asm_func(unsigned char, unsigned char);
\newline
-i = j / 1 ; /* changed to */ i = j;
-\family default
\newline
-
+int c_func (unsigned char i, unsigned char j) reentrant
\newline
-Note the subexpressions
-\begin_inset LatexCommand \index{subexpressions}
-
-\end_inset
-
- given above are generally introduced by macro expansions or as a result
- of copy/constant propagation.
-\layout Subsubsection
-
-'switch' Statements
-\begin_inset LatexCommand \index{switch Statements}
-
-\end_inset
-
-
-\layout Standard
-
-SDCC changes switch statements to jump tables
-\begin_inset LatexCommand \index{jump tables}
-
-\end_inset
-
- when the following conditions are true.
-
-\layout Itemize
-
-The case labels are in numerical sequence, the labels need not be in order,
- and the starting number need not be one or zero.
+{
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return asm_func(i,j);
\newline
-
-\family typewriter
-switch(i) {\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-switch (i) {
+}
\newline
-case 4:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 1: ...
-
+
\newline
-case 5:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 2: ...
-
+int main()
\newline
-case 3:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 3: ...
-
+{
\newline
-case 6:...
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
-case 4: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+return c_func(10,9);
\newline
-}\SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
- \SpecialChar ~
}
-\newline
-
-\newline
-
-\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.
-\layout Itemize
-
-The number of case labels is less than 84, since each label takes 3 bytes
- and a jump-table can be utmost 256 bytes long.
-
\layout Standard
-Switch statements which have gaps in the numeric sequence or those that
- have more that 84 case labels can be split into more than one switch statement
- for efficient code generation, e.g.:
-\newline
+The corresponding assembler routine is:
+\layout Verse
-\newline
\family typewriter
-switch (i) {
+.globl _asm_func
\newline
-case 1: ...
-
+_asm_func:
\newline
-case 2: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+push _bp
\newline
-case 3: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov _bp,sp
\newline
-case 4: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r2,dpl
\newline
-case 9: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,_bp
\newline
-case 10: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+clr c
\newline
-case 11: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,#0xfd
\newline
-case 12: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r0,a
\newline
-}
-\family default
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,#0xfc
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov r1,a
\newline
-If the above switch statement is broken down into two switch statements
-\newline
-
-\newline
-
-\family typewriter
-switch (i) {
-\newline
-case 1: ...
-
-\newline
-case 2: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov a,@r0
\newline
-case 3: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+add a,r2
\newline
-case 4: ...
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dpl,a
\newline
-}
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov dph,#0x00
\newline
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+mov sp,_bp
\newline
-
-\family default
-and
-\family typewriter
-
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+pop _bp
\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ret
+\layout Standard
-\newline
-switch (i) {
-\newline
-case 9: \SpecialChar ~
-...
-
-\newline
-case 10: ...
-
-\newline
-case 11: ...
-
-\newline
-case 12:\SpecialChar ~
-...
-
-\newline
-}
-\newline
+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
-\newline
+int (16 bit)
+\begin_inset LatexCommand \index{int (16 bit)}
-\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
-\begin_inset LatexCommand \index{Bit-shifting Operations}
+ and long (32 bit)
+\begin_inset LatexCommand \index{long (32 bit)}
\end_inset
-.
+ Support
\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.:
+For signed & unsigned int (16 bit) and long (32 bit) variables, division,
+ multiplication and modulus operations are implemented by support routines.
+ These support routines are all developed in ANSI-C to facilitate porting
+ to other MCUs, although some model specific assembler optimizations are
+ used.
+ The following files contain the described routines, all of them can be
+ found in <installdir>/share/sdcc/lib.
\newline
-\family typewriter
+\layout Standard
+\align center
-\newline
-unsigned char i;
-\newline
-...
-
-\newline
-i>>= 4;
-\newline
-...
-\newline
+\begin_inset Tabular
+<lyxtabular version="3" rows="11" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0(null)">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family default
+\layout Standard
-\newline
-generates the following code:
-\newline
-\family typewriter
+\series bold
+Function
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-mov a,_i
-\newline
-swap a
-\newline
-anl a,#0x0f
-\newline
-mov _i,a
-\family default
+\layout Standard
-\newline
-\newline
-In general SDCC will never setup a loop if the shift count is known.
- Another example:
-\newline
+\series bold
+Description
+\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
-unsigned int i;
-\newline
-...
-
-\newline
-i >>= 9;
-\newline
-...
-\family default
+_mulint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\newline
-will generate:
-\newline
+16 bit multiplication
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\family typewriter
-mov a,(_i + 1)
-\newline
-mov (_i + 1),#0x00
-\newline
-clr c
-\newline
-rrc a
-\newline
-mov _i,a
-\family default
+_divsint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\newline
-Note that SDCC stores numbers in little-endian format (i.e.
- lowest order first).
-\layout Subsubsection
+ 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
-Bit-rotation
-\begin_inset LatexCommand \index{Bit-rotation}
+\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
-A special case of the bit-shift operation is bit rotation, SDCC recognizes
- the following expression to be a left bit-rotation:
-\newline
+ 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
-\newline
+\layout Standard
-\family typewriter
-unsigned char i;
-\newline
-...
-
-\newline
-i = ((i << 1) | (i >> 7));
-\family default
+_modsint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-...
-\newline
+\layout Standard
-\newline
-will generate the following code:
-\newline
+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
-\newline
+\layout Standard
-\family typewriter
-mov a,_i
-\newline
-rl a
-\newline
-mov _i,a
-\family default
+_moduint.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\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.:
-\newline
+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
-\newline
+\layout Standard
-\family typewriter
-i = ((i >> 7) | (i << 1)); /* left-bit rotation */
-\layout Subsubsection
+_mullong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Highest Order Bit
-\begin_inset LatexCommand \index{Highest Order Bit}
+\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
-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
+ 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
-\newline
-
-\family typewriter
-unsigned int gint;
-\newline
+\layout Standard
-\newline
-foo () {
-\newline
-unsigned char hob;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-\SpecialChar ~
-\SpecialChar ~
-hob = (gint >> 15) & 1;
-\newline
-\SpecialChar ~
-\SpecialChar ~
-..
-
-\newline
-}
-\family default
+_divulong.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
+\layout Standard
-\newline
-will generate the following code:
-\newline
+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
-\family typewriter
\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 ~
- 61 ;\SpecialChar ~
- hob.c 7
-\newline
-\SpecialChar ~
-\SpecialChar ~
- 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 ~
- a,(_gint + 1)
-\newline
-\SpecialChar ~
-\SpecialChar ~
- 000C 33\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 ~
- rlc\SpecialChar ~
- a
-\newline
-\SpecialChar ~
-\SpecialChar ~
- 000D E4\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 64\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- clr\SpecialChar ~
- a
-\newline
-\SpecialChar ~
-\SpecialChar ~
- 000E 13\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 65\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- rrc\SpecialChar ~
- a
-\newline
-\SpecialChar ~
-\SpecialChar ~
- 000F F5*02\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- 66\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- mov\SpecialChar ~
- _foo_hob_1_1,a
+
+\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
-\newline
+\layout Standard
+\align center
-\family default
-Variations of this case however will
-\emph on
-not
-\emph default
- be recognized.
- It is a standard C expression, so I heartily recommend this be the only
- way to get the highest order bit, (it is portable).
- Of course it will be recognized even if it is embedded in other expressions,
- e.g.:
-\newline
+\size footnotesize
-\newline
+\begin_inset Tabular
+<lyxtabular version="3" rows="17" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0(null)">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\family typewriter
-xyz = gint + ((gint >> 15) & 1);
-\family default
+\layout Standard
-\newline
-\newline
-will still be recognized.
-\layout Subsubsection
+\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
-Peephole Optimizer
-\begin_inset LatexCommand \index{Peephole optimizer}
+\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
-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
----peep-file
-\begin_inset LatexCommand \index{---peep-file}
+\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
- <filename>
-\emph default
- option.
- The rule language is best illustrated with examples.
-\newline
+\layout Standard
-\newline
-\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
+\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
-\newline
+\layout Standard
-\newline
-The above rule will change the following assembly sequence:
-\newline
-\newline
+\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
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-mov r1,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov a,r1
-\family default
+\layout Standard
-\newline
-\newline
-to
-\newline
+\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
-\newline
+\layout Standard
-\family typewriter
-mov r1,a
-\family default
-\newline
+\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
-\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
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-mov r1,a
-\newline
-\SpecialChar ~
-\SpecialChar ~
-mov a,r2
-\family default
+\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
-\newline
+\layout Standard
-\newline
-will remain unmodified.
-\newline
-\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
+\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
-\newline
+\layout Standard
-\newline
-\family typewriter
-replace { lcall %1 } by { acall %1 }
-\newline
-replace { ljmp %1 } by { ajmp %1 }
-\family default
+\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
-\newline
+\layout Standard
-\newline
-The
-\emph on
-inline-assembler code
-\emph default
- is also passed through the peep hole optimizer, thus the peephole optimizer
- can also be used as an assembly level macro expander.
- The rules themselves are MCU dependent whereas the rule language infra-structur
-e is MCU independent.
- Peephole optimization rules for other MCU can be easily programmed using
- the rule language.
-\newline
-\newline
-The syntax for a rule is as follows:
-\newline
+\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
-\newline
+\layout Standard
-\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
-\family default
+\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
-\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
+_fs2char.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="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
-\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
+\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
-\newline
+\layout Standard
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-pop ar1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-pop ar2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar2
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar1
-\family default
-\newline
+\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
-\newline
-would result in:
-\newline
+\layout Standard
-\newline
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-pop ar1
-\newline
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\newline
-\SpecialChar ~
-\SpecialChar ~
-push ar1
-\family default
+\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
-\newline
+\layout Standard
-\newline
-\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
+\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
-\newline
+\layout Standard
-\family typewriter
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\newline
-\SpecialChar ~
-\SpecialChar ~
-; nop
-\family default
-\newline
+\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
-\newline
-A conditional function can be attached to a rule.
- Attaching rules are somewhat more involved, let me illustrate this with
- an example.
-\newline
+\layout Standard
-\newline
-\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 roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+_fs2ulong.
\family default
-
-\newline
-
-\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
+\series default
+\shape default
+\size default
\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
-\begin_inset LatexCommand \index{Pragmas}
-
+\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
-SDCC supports the following #pragma directives.
-\layout Itemize
-
-SAVE
-\begin_inset LatexCommand \index{\#pragma SAVE}
+\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
- - this will save all current options to the SAVE/RESTORE stack.
- See RESTORE.
-\layout Itemize
+\layout Standard
-RESTORE
-\begin_inset LatexCommand \index{\#pragma RESTORE}
+\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
- - 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
+\layout Standard
-NOGCSE
-\begin_inset LatexCommand \index{\#pragma NOGCSE}
+\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
- - will stop global subexpression elimination.
-\layout Itemize
+\layout Standard
-NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+\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
- - will stop loop induction optimizations.
-\layout Itemize
+\layout Standard
-NOJTBOUND
-\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+\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
- - will not generate code for boundary value checking, when switch statements
- are turned into jump-tables.
-\layout Itemize
+\layout Standard
-NOOVERLAY
-\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+\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
- - the compiler will not overlay the parameters and local variables of a
- function.
-\layout Itemize
+\layout Standard
-LESS_PEDANTIC
-\begin_inset LatexCommand \index{\#pragma LESS\_PEDANTIC}
+\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
- - the compiler will not warn you anymore for obvious mistakes, you'r on
- your own now ;-(
-\layout Itemize
+\layout Standard
-NOLOOPREVERSE
-\begin_inset LatexCommand \index{\#pragma NOLOOPREVERSE}
+\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
- - Will not do loop reversal optimization
-\layout Itemize
+\layout Standard
-EXCLUDE
-\begin_inset LatexCommand \index{\#pragma EXCLUDE}
+\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
- 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
+\layout Standard
-NOIV
-\begin_inset LatexCommand \index{\#pragma NOIV}
+\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
- - 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
-CALLEE-SAVES
-\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+\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
- 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 typewriter
-#pragma SAVE
-\begin_inset LatexCommand \index{\#pragma SAVE}
+\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
- /* save the current settings */
-\newline
-#pragma NOGCSE
-\begin_inset LatexCommand \index{\#pragma NOGCSE}
-
-\end_inset
+\layout Standard
- /* turnoff global subexpression elimination */
-\newline
-#pragma NOINDUCTION
-\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
+\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
+
- /* turn off induction optimizations */
-\newline
-int foo ()
-\newline
-{
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-\SpecialChar ~
- \SpecialChar ~
- /* large code */
-\newline
-\SpecialChar ~
- \SpecialChar ~
- ...
-
-\newline
-}
-\newline
-#pragma RESTORE
-\begin_inset LatexCommand \index{\#pragma RESTORE}
-
+\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
- /* turn the optimizations back on */
-\family default
+\layout Standard
-\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
+\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
-\emph on
-<pending: this is messy and incomplete>
-\emph default
- Library Routines
-\layout Enumerate
-Compiler support routines (_gptrget, _mulint etc)
-\layout Enumerate
+\newline
-Stdclib functions (puts, printf, strcat etc)
-\layout Enumerate
+\layout Standard
-Math functions (sin, pow, sqrt etc)
+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
-Interfacing with Assembly Routines
-\begin_inset LatexCommand \index{Assembly Routines}
+MCS51 Memory Models
+\begin_inset LatexCommand \index{Memory model}
\end_inset
-\layout Subsubsection
-
-Global Registers used for Parameter Passing
-\begin_inset LatexCommand \index{Parameter Passing}
+\begin_inset LatexCommand \index{MCS51 memory}
\end_inset
\layout Standard
-The compiler always uses the global registers
+SDCC allows two memory models for MCS51 code,
+\shape slanted
+small
+\shape default
+ and
+\shape slanted
+large
+\shape default
+.
+ Modules compiled with different memory models should
\emph on
-DPL
-\begin_inset LatexCommand \index{DPL}
+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
-,DPH
-\begin_inset LatexCommand \index{DPH}
+ 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{DPTR}
+\begin_inset LatexCommand \index{DS390 memory model}
\end_inset
-,B
-\begin_inset LatexCommand \index{B}
+
+\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
+Note that the compiler does not generate any code to place the processor
+ into 24 bitmode (although
+\emph on
+tinibios
\emph default
-and
+ in the ds390 libraries will do that for you).
+ If you don't use
\emph on
- ACC
-\begin_inset LatexCommand \index{ACC}
+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
- 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).
+ option, variables will by default be placed into the XDATA segment.
-\layout Subsubsection
+\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
-Assembler Routine(non-reentrant)
-\begin_inset LatexCommand \index{Assembler Routine(non-reentrant)}
+Pragmas
+\begin_inset LatexCommand \index{Pragmas}
\end_inset
\layout Standard
-In the following example the function cfunc calls an assembler routine asm_func,
- which takes two parameters.
-\newline
+SDCC supports the following #pragma directives.
+\layout Itemize
-\newline
+SAVE
+\begin_inset LatexCommand \index{\#pragma SAVE}
-\family typewriter
-extern int asm_func(unsigned char, unsigned char);
-\newline
+\end_inset
-\newline
-int c_func (unsigned char i, unsigned char j)
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return asm_func(i,j);
-\newline
-}
-\newline
+ - this will save all current options to the SAVE/RESTORE stack.
+ See RESTORE.
+\layout Itemize
-\newline
-int main()
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-return c_func(10,9);
-\newline
-}
-\newline
+RESTORE
+\begin_inset LatexCommand \index{\#pragma RESTORE}
-\newline
+\end_inset
-\family default
-The corresponding assembler function is:
-\newline
+ - 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
-\newline
+NOGCSE
+\begin_inset LatexCommand \index{\#pragma NOGCSE}
-\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
+\end_inset
-\newline
+ - will stop global common subexpression elimination.
+\layout Itemize
-\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
+NOINDUCTION
+\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
-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
+ - will stop loop induction optimizations.
+\layout Itemize
+
+NOJTBOUND
+\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+
\end_inset
- for One bye parameter,
-\begin_inset Quotes eld
+ - will not generate code for boundary value checking, when switch statements
+ are turned into jump-tables (dangerous).
+
+\layout Itemize
+
+NOOVERLAY
+\begin_inset LatexCommand \index{\#pragma NOOVERLAY}
+
\end_inset
-dptr
-\begin_inset Quotes erd
+ - 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
- if two bytes,
-\begin_inset Quotes eld
+ - 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
-b,dptr
-\begin_inset Quotes erd
+ - Will not do loop reversal optimization
+\layout Itemize
+
+EXCLUDE
+\begin_inset LatexCommand \index{\#pragma EXCLUDE}
+
\end_inset
- for three bytes and
-\begin_inset Quotes eld
+ NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation of
+ pair of push/pop
+\begin_inset LatexCommand \index{push/pop}
+
\end_inset
-acc,b,dptr
-\begin_inset Quotes erd
+ instruction in ISR function (using interrupt
+\begin_inset LatexCommand \index{interrupt}
+
\end_inset
- for four bytes, the varible name for the second parameter will be _<function_na
-me>_PARM_2.
-\newline
+ 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
-Assemble the assembler routine with the following command:
-\newline
+\end_inset
-\newline
+.
+\layout Itemize
-\family sans
-\series bold
-asx8051 -losg asmfunc.asm
-\newline
+NOIV
+\begin_inset LatexCommand \index{\#pragma NOIV}
-\newline
+\end_inset
-\family default
-\series default
-Then compile and link the assembler routine to the C source file with the
- following command:
-\newline
+ - 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
-\newline
+CALLEE-SAVES
+\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+
+\end_inset
-\family sans
-\series bold
-sdcc cfunc.c asmfunc.rel
-\layout Subsubsection
-Assembler Routine(reentrant)
-\begin_inset LatexCommand \index{Assembler Routine(reentrant)}
+\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
-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
+\backslash
+/
+\end_inset
+
+-callee-saves command line option is used, the function names specified
+ in #pragma\SpecialChar ~
+CALLEE-SAVES
+\begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
+
+\end_inset
+
+ is appended to the list of functions specified in the command line.
+\layout Standard
+
+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
-extern int asm_func(unsigned char, unsigned char);
-\newline
+#pragma SAVE
+\begin_inset LatexCommand \index{\#pragma SAVE}
-\newline
-int c_func (unsigned char i, unsigned char j) reentrant
-\newline
-{
-\newline
+\end_inset
+
+ \SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return asm_func(i,j);
-\newline
-}
+\SpecialChar ~
+\SpecialChar ~
+/* save the current settings */
\newline
+#pragma NOGCSE
+\begin_inset LatexCommand \index{\#pragma NOGCSE}
-\newline
-int main()
-\newline
-{
-\newline
+\end_inset
+
+ \SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-return c_func(10,9);
-\newline
-}
+/* turnoff global subexpression elimination */
\newline
+#pragma NOINDUCTION
+\begin_inset LatexCommand \index{\#pragma NOINDUCTION}
-\family default
-
-\newline
-The corresponding assembler routine is:
-\newline
+\end_inset
+ /* turn off induction optimizations */
\newline
-
-\family typewriter
-.globl _asm_func
+int foo ()
\newline
-_asm_func:
+{
\newline
\SpecialChar ~
+ \SpecialChar ~
+ ...
+
+\newline
\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
+ \SpecialChar ~
+ /* large code */
\newline
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-ret
+ \SpecialChar ~
+ ...
+
\newline
-
+}
\newline
-
-\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
-
-External Stack
-\begin_inset LatexCommand \index{External Stack}
+#pragma RESTORE
+\begin_inset LatexCommand \index{\#pragma RESTORE}
\end_inset
-
-\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).
+ /* turn the optimizations back on */
\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.
+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
-ANSI-Compliance
-\begin_inset LatexCommand \index{ANSI-Compliance}
+Defines Created by the Compiler
+\begin_inset LatexCommand \index{Defines created by the compiler}
\end_inset
\layout Standard
-Deviations from the compliancy.
-\layout Itemize
-
-functions are not always reentrant.
-\layout Itemize
+The compiler creates the following #defines
+\begin_inset LatexCommand \index{\#defines}
-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
+\end_inset
+:
\newline
-\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
-'double' precision floating point not supported.
-\layout Itemize
+\begin_inset Tabular
+<lyxtabular version="3" rows="10" columns="2">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0(null)">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-No support for setjmp and longjmp (for now).
-\layout Itemize
+\layout Standard
-Old K&R style function declarations are NOT allowed.
-\newline
-\family typewriter
+\series bold
+#define
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-foo(i,j) /* this old style of function declarations */
-\newline
-int i,j; /* are valid in ANSI but not valid in SDCC */
-\newline
-{
-\newline
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-...
-
-\newline
-}
-\layout Itemize
+\layout Standard
-functions declared as pointers must be dereferenced during the call.
-\newline
-\family typewriter
+\series bold
+Description
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
-\newline
-int (*foo)();
-\newline
-...
-
-\newline
-/* has to be called like this */
-\newline
-(*foo)(); /* ansi standard allows calls to be made like 'foo()' */
-\layout Subsection
+\layout Standard
-Cyclomatic Complexity
-\begin_inset LatexCommand \index{Cyclomatic Complexity}
+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
-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
+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
-complexity = (number of edges in control flow graph) - (number of nodes
- in control flow graph) + 2;
-\newline
+SDCC_mcs51
+\begin_inset LatexCommand \index{SDCC\_mcs51}
-\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
+\end_inset
-TIPS
-\layout Standard
+ or SDCC_ds390
+\begin_inset LatexCommand \index{SDCC\_ds390}
-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
+\end_inset
-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
+ or SDCC_z80
+\begin_inset LatexCommand \index{SDCC\_z80}
-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
+\end_inset
-NEVER jump into a LOOP.
-\layout Itemize
+, etc
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Declare the variables to be local whenever possible, especially loop control
- variables (induction).
-\layout Itemize
+\layout Standard
-Since the compiler does not always do implicit integral promotion, the programme
-r should do an explicit cast when integral promotion is required.
-\layout Itemize
+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
-Reducing the size of division, multiplication & modulus operations can reduce
- code size substantially.
- Take the following code for example.
-\family typewriter
+\layout Standard
-\newline
+__mcs51
+\begin_inset LatexCommand \index{\_\_mcs51}
-\newline
-foobar(unsigned int p1, unsigned char ch)
-\newline
-{
-\newline
- unsigned char ch1 = p1 % ch ;
-\newline
- ....
-
-\newline
-}
-\newline
+\end_inset
-\family default
+ or __ds390
+\begin_inset LatexCommand \index{\_\_ds390}
-\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
+\end_inset
-\family typewriter
+ or __z80
+\begin_inset LatexCommand \index{\_\_z80}
-\newline
-foobar(unsigned int p1, unsigned char ch)
-\newline
-{
-\newline
- unsigned char ch1 = (unsigned char)p1 % ch ;
-\newline
- ....
-
-\newline
-}
-\newline
+\end_inset
-\family default
+, etc
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\newline
-It would substantially reduce the code generated (future versions of the
- compiler will be smart enough to detect such optimization oppurtunities).
-\layout Subsection
+\layout Standard
-Notes on MCS51 memory
-\begin_inset LatexCommand \index{MCS51 memory}
+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
- layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
\layout Standard
-The 8051 family of micro controller have a minimum of 128 bytes of internal
- memory which is structured as follows
-\newline
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-\newline
-- Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R7 to R7
-
-\newline
-- Bytes 20-2F - 16 bytes to hold 128 bit variables and
-\newline
-- Bytes 30-7F - 60 bytes for general purpose use.
-\newline
+\layout Standard
-\newline
-Normally the SDCC compiler will only utilise the first bank
-\begin_inset LatexCommand \index{bank}
+\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
- of registers, but it is possible to specify that other banks of registers
- should be used in interrupt
-\begin_inset LatexCommand \index{interrupt}
+\layout Standard
+
+SDCC_MODEL_SMALL
+\begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
\end_inset
- routines.
- By default, the compiler will place the stack after the last bank of used
- registers, i.e.
- if the first 2 banks of registers are used, it will position the base of
- the internal stack at address 16 (0X10).
- This implies that as the stack
-\begin_inset LatexCommand \index{stack}
\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
- grows, it will use up the remaining register banks, and the 16 bytes used
- by the 128 bit variables, and 60 bytes for general purpose use.
\layout Standard
-By default, the compiler uses the 60 general purpose bytes to hold "near
- data".
- The compiler/optimiser may also declare some Local Variables in this area
- to hold local data.
-
-\layout Standard
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-If any of the 128 bit variables are used, or near data is being used then
- care needs to be taken to ensure that the stack does not grow so much that
- it starts to over write either your bit variables or "near data".
- There is no runtime checking to prevent this from happening.
\layout Standard
-The amount of stack being used is affected by the use of the "internal stack"
- to save registers before a subroutine call is made (---stack-auto
-\begin_inset LatexCommand \index{---stack-auto}
+\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
- 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_MODEL_LARGE
+\begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
+
+\end_inset
----stack-loc
-\begin_inset LatexCommand \index{---stack-loc}
\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
- 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
-\begin_inset LatexCommand \index{---stack-after-data}
+\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
-, 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
----data-loc
-\begin_inset LatexCommand \index{---data-loc}
+SDCC_USE_XSTACK
+\begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
\end_inset
- allows you to specify the start address of the near data.
- This could be used to move the "near data" further away from the stack
- giving it more room to grow.
- This will only work if no bit variables are being used and the stack can
- grow to use the bit variable space.
-\newline
-\newline
-Conclusion.
-\newline
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-\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
+when
+\emph on
+-
+\begin_inset ERT
+status Collapsed
-Retargetting for other MCUs.
\layout Standard
-The issues for retargetting the compiler are far too numerous to be covered
- by this document.
- What follows is a brief description of each of the seven phases of the
- compiler and its MCU dependency.
-\layout Itemize
+\backslash
+/
+\end_inset
-Parsing the source and building the annotated parse tree.
- This phase is largely MCU independent (except for the language extensions).
- Syntax & semantic checks are also done in this phase, along with some initial
- optimizations like back patching labels and the pattern matching optimizations
- like bit-rotation etc.
-\layout Itemize
+-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
-The second phase involves generating an intermediate code which can be easy
- manipulated during the later phases.
- This phase is entirely MCU independent.
- The intermediate code generation assumes the target machine has unlimited
- number of registers, and designates them with the name iTemp.
- The compiler can be made to dump a human readable form of the code generated
- by using the ---dumpraw option.
-\layout Itemize
+\layout Standard
-This phase does the bulk of the standard optimizations and is also MCU independe
-nt.
- This phase can be broken down into several sub-phases:
-\newline
+SDCC_STACK_TENBIT
+\begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
-\newline
-Break down intermediate code (iCode) into basic blocks.
-\newline
-Do control flow & data flow analysis on the basic blocks.
-\newline
-Do local common subexpression elimination, then global subexpression elimination
-\newline
-Dead code elimination
-\newline
-Loop optimizations
-\newline
-If loop optimizations caused any changes then do 'global subexpression eliminati
-on' and 'dead code elimination' again.
-\layout Itemize
+\end_inset
-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.
-\layout Itemize
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
-Phase five is register allocation.
- There are two parts to this process.
-\newline
+\layout Standard
-\newline
-The first part I call 'register packing' (for lack of a better term).
- In this case several MCU specific expression folding is done to reduce
- register pressure.
-\newline
+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
-\newline
-The second part is more MCU independent and deals with allocating registers
- to the remaining live ranges.
- A lot of MCU specific code does creep into this phase because of the limited
- number of index registers available in the 8051.
-\layout Itemize
+\layout Standard
-The Code generation phase is (unhappily), entirely MCU dependent and very
- little (if any at all) of this code can be reused for other MCU.
- However the scheme for allocating a homogenized assembler operand for each
- iCode operand may be reused.
-\layout Itemize
+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
-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}
+Debugging with SDCDB
+\begin_inset LatexCommand \index{sdcdb}
\end_inset
- - Source Level Debugger
+
+\layout Standard
+
+SDCC is distributed with a source level debugger
\begin_inset LatexCommand \index{Debugger}
\end_inset
+.
+ The debugger uses a command line interface, the command repertoire of the
+ debugger has been kept as close to gdb
+\begin_inset LatexCommand \index{gdb}
-\layout Standard
+\end_inset
-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.
+ (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
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.
+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 &
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
Debugger Commands.
\layout Standard
-As mention earlier the command interface for the debugger has been deliberately
- kept as close the GNU debugger gdb, as possible.
+As mentioned earlier the command interface for the debugger has been deliberatel
+y kept as close the GNU debugger gdb, as possible.
This will help the integration with existing graphical user interfaces
(like ddd, xxgdb or xemacs) existing for the GNU debugger.
-\layout Subsubsection
+ If you use a graphical user interface for the debugger you can skip the
+ next sections.
+\layout Subsubsection*
break [line | file:line | function | file:function]
\layout Standard
sdcdb>break funcfoo
\newline
sdcdb>break foo.c:funcfoo
-\layout Subsubsection
+\layout Subsubsection*
clear [line | file:line | function | file:function ]
\layout Standard
sdcdb>clear funcfoo
\newline
sdcdb>clear foo.c:funcfoo
-\layout Subsubsection
+\layout Subsubsection*
continue
\layout Standard
Continue program being debugged, after breakpoint.
-\layout Subsubsection
+\layout Subsubsection*
finish
\layout Standard
Execute till the end of the current function.
-\layout Subsubsection
+\layout Subsubsection*
delete [n]
\layout Standard
Delete breakpoint number 'n'.
If used without any option clear ALL user defined break points.
-\layout Subsubsection
+\layout Subsubsection*
info [break | stack | frame | registers ]
\layout Itemize
\layout Itemize
info registers - show content of all registers.
-\layout Subsubsection
+\layout Subsubsection*
step
\layout Standard
Step program until it reaches a different source line.
-\layout Subsubsection
+\layout Subsubsection*
next
\layout Standard
Step program, proceeding through subroutine calls.
-\layout Subsubsection
+\layout Subsubsection*
run
\layout Standard
Start debugged program.
-\layout Subsubsection
+\layout Subsubsection*
ptype variable
\layout Standard
Print type information of the variable.
-\layout Subsubsection
+\layout Subsubsection*
print variable
\layout Standard
print value of variable.
-\layout Subsubsection
+\layout Subsubsection*
file filename
\layout Standard
load the given file name.
Note this is an alternate method of loading file for debugging.
-\layout Subsubsection
+\layout Subsubsection*
frame
\layout Standard
print information about current frame.
-\layout Subsubsection
+\layout Subsubsection*
set srcmode
\layout Standard
Toggle between C source & assembly source.
-\layout Subsubsection
+\layout Subsubsection*
! simulator command
\layout Standard
Note the debugger does not interpret the command being sent to the simulator,
so if a command like 'go' is sent the debugger can loose its execution
context and may display incorrect values.
-\layout Subsubsection
+\layout Subsubsection*
quit.
\layout Standard
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
---------
+--------
\newline
;;
\newline
\SpecialChar ~
Goto the SDCDB output buffer
\newline
-;; p\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdb-print-c-sexp\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-SDCDB print command for data at
+;; p\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-print-c-sexp\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB print command for data at
+\newline
+;;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ buffer point
+\newline
+;; g\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-goto-sdcdb\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Goto the SDCDB output buffer
+\newline
+;; t\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-mode\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Toggles Sdcdbsrc mode (turns it off)
+\newline
+;;
+\newline
+;; C-c C-f\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-finish-from-src\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+SDCDB finish command
+\newline
+;;
+\newline
+;; C-x SPC\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdb-break\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Set break for line with point
+\newline
+;; ESC t\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-mode\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+Toggle Sdcdbsrc mode
+\newline
+;; ESC m\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ sdcdbsrc-srcmode\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ Toggle list mode
+\newline
+;;
+\newline
+
+\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 ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+unsigned char ch1 = (unsigned char)p1 % ch ;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+....
+\newline
+}
+\layout Standard
+
+It would substantially reduce the code generated (future versions of the
+ compiler will be smart enough to detect such optimization opportunities).
+\end_deeper
+\layout Itemize
+
+Have a look at the assembly listing to get a
+\begin_inset Quotes sld
+\end_inset
+
+feeling
+\begin_inset Quotes srd
+\end_inset
+
+ for the code generation.
+\layout 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
+
+\newline
+- Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
+
+\newline
+- Bytes 20-2F - 16 bytes to hold 128 bit
+\begin_inset LatexCommand \index{bit}
+
+\end_inset
+
+ variables and,
+\newline
+- Bytes 30-7F - 80 bytes for general purpose use.
+\newline
+
+\layout Standard
+
+Additionally some members of the MCS51 family may have up to 128 bytes of
+ additional, indirectly addressable, internal RAM memory (
+\emph on
+idata
+\emph default
+
+\begin_inset LatexCommand \index{idata}
+
+\end_inset
+
+).
+ Furthermore, some chips may have some built in external memory (
+\emph on
+xdata
+\emph default
+
+\begin_inset LatexCommand \index{xdata}
+
+\end_inset
+
+) which should not be confused with the internal, directly addressable RAM
+ memory (
+\emph on
+data
+\emph default
+
+\begin_inset LatexCommand \index{data}
+
+\end_inset
+
+).
+ Sometimes this built in
+\emph on
+xdata
+\emph default
+ memory has to be activated before using it (you can probably find this
+ information on the datasheet of the microcontroller your are using).
+\layout Standard
+
+Normally SDCC will only use the first bank
+\begin_inset LatexCommand \index{bank}
+
+\end_inset
+
+ of registers (register bank 0), but it is possible to specify that other
+ banks of registers should be used in interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ routines.
+ By default, the compiler will place the stack after the last byte of allocated
+ memory for variables.
+ For example, if the first 2 banks of registers are used, and only four
+ bytes are used for
+\emph on
+data
+\emph default
+ 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
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-data-loc
+\begin_inset LatexCommand \index{-\/-data-loc}
+
+\end_inset
+
+ to specify the start address of the
+\emph on
+data
+\emph default
+ 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
+idata
+\emph default
+).
+
+\layout Standard
+
+By default the 8051 linker will place the stack after the last byte of data
+ variables.
+ Option -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-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
+\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
+
+header file conversion
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+mh2h.c
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+header file conversion
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc/support/scripts
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+as-gbz80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+as-z80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+asx8051
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Assembler
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcdb
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+aslink
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\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
+
+link-z80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\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
+
+link-gbz80
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Linker
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+packihx
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+ihx packer
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+sdcc/bin
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\layout Subsection
+
+Related open source tools
+\begin_inset LatexCommand \index{Related tools}
+
+\end_inset
+
+
+\layout Standard
+\align center
+
+\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
+
+\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
+
+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
+
+gpsim
+\begin_inset LatexCommand \index{gpsim}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+PIC simulator
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\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
+
+\layout Standard
+
+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}
+
+\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
+
+srecord
+\begin_inset LatexCommand \index{srecord}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\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/}
+
+\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
+
+objdump
+\begin_inset LatexCommand \index{objdump}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Object file conversion, ...
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\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
+
+\layout Standard
+
+doxygen
+\begin_inset LatexCommand \index{doxygen}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Source code documentation system
+\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.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
+
+\layout Standard
+
+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
+
+\layout Standard
+
+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
+
+
+\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
+
+ddd
+\begin_inset LatexCommand \index{ddd}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Debugger, serves nicely as GUI to sdcdb
+\begin_inset LatexCommand \index{sdcdb}
+
+\end_inset
+
+ (Unix only)
+\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
+
+\layout Subsection
+
+Related documentation / recommended reading
+\layout Standard
+\align center
+
+\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
+
+\layout Standard
+
+Name
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+Subject / Title
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\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
+
+\layout Standard
+
+C Reference Card
+\begin_inset LatexCommand \index{C Reference card}
+
+\end_inset
+
+, 2 pages
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\begin_inset LatexCommand \url{http://www.refcards.com/about/c.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
+
+test_suite_spec.pdf
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc regression test
+\begin_inset LatexCommand \index{Regression test}
+
+\end_inset
+
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc/doc
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+
+\family roman
+\series medium
+\shape up
+\size normal
+\emph off
+\bar no
+\noun off
+\color none
+cdbfileformat.pd
+\family default
+\series default
+\shape default
+\size default
+\emph default
+\bar default
+\noun default
+\color default
+f
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc internal documentation
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\layout Standard
+
+sdcc/doc
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\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
+ well over 100,000 lines of code (blank stripped).
+ The open source nature of this project is a key to its continued growth
+ and support.
+ You gain the benefit and support of many active software developers and
+ end users.
+ Is SDCC perfect? No, that's why we need your help.
+ The developers take pride in fixing reported bugs.
+ You can help by reporting the bugs and helping other SDCC users.
+ There are lots of ways to contribute, and we encourage you to take part
+ in making SDCC a great software package.
+
+\layout Standard
+
+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
+
+
+\begin_inset LatexCommand \index{Reporting bugs}
+
+\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
+
+Requesting Features
+\begin_inset LatexCommand \label{sub:Requesting-Features}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Feature request}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Requesting features}
+
+\end_inset
+
+
+\layout Standard
+
+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
+
+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
+
+\layout Standard
+
+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
+
+ChangeLog
+\begin_inset LatexCommand \index{Changelog}
+
+\end_inset
+
+
+\layout Standard
+
+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
+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
+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
+
+
+\layout Verse
+
+
+\family typewriter
+int global;
+\newline
+
+\newline
+void f () {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+int i;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+i = 1; \SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+/* dead store */
+\newline
+\SpecialChar ~
+\SpecialChar ~
+global = 1;\SpecialChar ~
+/* dead store */
+\newline
+\SpecialChar ~
+\SpecialChar ~
+global = 2;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+return;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+global = 3;\SpecialChar ~
+/* unreachable */
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int global;
+\newline
+
+\newline
+void f () {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+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 ~
+int i, j;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+i = 10;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+j = i;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+return j;
+\newline
+}
+\layout Standard
+
+will be changed to
+\layout Verse
+
+
+\family typewriter
+int f() {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+int i, j;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+i = 10;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+j = 10;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+return 10;
+\newline
+}
+\layout Standard
+
+Note: the dead stores created by this copy propagation will be eliminated
+ by dead-code elimination.
+\layout 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 ~
+\SpecialChar ~
+\SpecialChar ~
+f += k + l;
+\layout Standard
+
+changed to
+\layout Verse
+
+
+\family typewriter
+itemp = k + l;
+\newline
+for (i = 0; i < 100; i++)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+f += itemp;
+\layout Standard
+
+As mentioned previously some loop invariants are not as apparent, all static
+ address computations are also moved out of the loop.
+\newline
+
+\newline
+Strength Reduction
+\begin_inset LatexCommand \index{Strength reduction}
+
+\end_inset
+
+, this optimization substitutes an expression by a cheaper expression:
+\layout Verse
+
+
+\family typewriter
+for (i=0;i < 100; i++)
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+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 ~
+ar[itemp1] = itemp2;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+itemp1 += 5;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+itemp2 += 3;
+\newline
+}
+\layout Standard
+
+The more expensive multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ is changed to a less expensive addition.
+\layout 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
+
+The 'for' loop is of the form
+\newline
+
+\newline
+
+\family typewriter
+for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
+ += 1])
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+<for body>
+\layout Itemize
+
+The <for body> does not contain
+\begin_inset Quotes eld
+\end_inset
+
+continue
+\begin_inset Quotes erd
+\end_inset
+
+ or 'break
+\begin_inset Quotes erd
+\end_inset
+
+.
+\layout Itemize
+
+All goto's are contained within the loop.
+\layout Itemize
+
+No function calls within the loop.
+\layout Itemize
+
+The loop control variable <sym> is not assigned any value within the loop
+\layout Itemize
+
+The loop control variable does NOT participate in any arithmetic operation
+ within the loop.
+\layout Itemize
+
+There are NO switch statements in the loop.
+\layout Subsubsection
+
+Algebraic Simplifications
+\layout Standard
+
+SDCC does numerous algebraic simplifications, the following is a small sub-set
+ of these optimizations.
+\layout Verse
+
+
+\family typewriter
+i = j + 0 ; /* changed to */ i = j;
+\newline
+i /= 2;\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+ /* changed to */ i >>= 1;
+\newline
+i = j - j ; /* changed to */ i = 0;
+\newline
+i = j / 1 ; /* changed to */ i = j;
+\layout Standard
+
+Note the subexpressions
+\begin_inset LatexCommand \index{Subexpression}
+
+\end_inset
+
+ given above are generally introduced by macro expansions or as a result
+ of copy/constant propagation.
+\layout Subsubsection
+
+'switch' Statements
+\begin_inset LatexCommand \index{switch statement}
+
+\end_inset
+
+
+\layout Standard
+
+SDCC changes switch statements to jump tables
+\begin_inset LatexCommand \index{jump tables}
+
+\end_inset
+
+ when the following conditions are true.
+
+\layout Itemize
+
+The case labels are in numerical sequence, the labels need not be in order,
+ and the starting number need not be one or zero.
+\begin_deeper
+\layout Verse
+
+
+\family typewriter
+switch(i) {\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\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 ~
+\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 0: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+case 5: ...\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 ~
+case 1: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...\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 ~
+case 2: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+case 6: ...\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 ~
+case 3: ...
+
+\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 ~
+}
+\layout Standard
+
+Both the above switch statements will be implemented using a jump-table.
+ The example to the right side is slightly more efficient as the check for
+ the lower boundary of the jump-table is not needed.
+\end_deeper
+\layout Itemize
+
+The number of case labels is at least three, since it takes two conditional
+ statements to handle the boundary conditions.
+\layout Itemize
+
+The number of case labels is less than 84, since each label takes 3 bytes
+ and a jump-table can be utmost 256 bytes long.
+\layout Standard
+
+Switch statements which have gaps in the numeric sequence or those that
+ have more that 84 case labels can be split into more than one switch statement
+ for efficient code generation, e.g.:
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 1: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 2: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 4: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 9: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 10: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 11: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 12: ...
+
+\newline
+}
+\layout Standard
+
+If the above switch statement is broken down into two switch statements
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 1: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 2: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 3: ...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 4: ...
+
+\newline
+}
+\layout Standard
+
+and
+\layout Verse
+
+
+\family typewriter
+switch (i) {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 9:\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 10:\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 11:\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+case 12:\SpecialChar ~
+...
+
+\newline
+}
+\layout Standard
+
+then both the switch statements will be implemented using jump-tables whereas
+ the unmodified switch statement will not be.
+ You might also consider dummy cases 0 and 5 to 8 in this example.
+ The pragma NOJTBOUND
+\begin_inset LatexCommand \index{\#pragma NOJTBOUND}
+
+\end_inset
+
+ can be used to turn off checking the
+\emph on
+j
+\emph default
+ump
+\emph on
+t
+\emph default
+able
+\emph on
+bound
+\emph default
+aries.
+\layout Subsubsection
+
+Bit-shifting Operations
+\begin_inset LatexCommand \index{Bit shifting}
+
+\end_inset
+
+.
+\layout Standard
+
+Bit shifting is one of the most frequently used operation in embedded programmin
+g.
+ SDCC tries to implement bit-shift operations in the most efficient way
+ possible, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned char i;
+\newline
+...
+
+\newline
+i >>= 4;
+\newline
+...
+\layout Standard
+
+generates the following code:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
+ a,_i
+\newline
+swap a
+\newline
+anl\SpecialChar ~
+ a,#0x0f
+\newline
+mov\SpecialChar ~
+ _i,a
+\layout Standard
+
+In general SDCC will never setup a loop if the shift count is known.
+ Another example:
+\layout Verse
+
+
+\family typewriter
+unsigned int i;
+\newline
+...
+
+\newline
+i >>= 9;
+\newline
+...
+\layout Standard
+
+will generate:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
+\SpecialChar ~
+a,(_i + 1)
+\newline
+mov\SpecialChar ~
+\SpecialChar ~
+(_i + 1),#0x00
+\newline
+clr\SpecialChar ~
+\SpecialChar ~
+c
+\newline
+rrc\SpecialChar ~
+\SpecialChar ~
+a
+\newline
+mov\SpecialChar ~
+\SpecialChar ~
+_i,a
+\layout Standard
+
+Note that SDCC stores numbers in little-endian
+\begin_inset LatexCommand \index{little-endian}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Endianness}
+
+\end_inset
+
+ 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
+unsigned char i;
+\newline
+...
+
+\newline
+i = ((i << 1) | (i >> 7));
+\family default
+
+\newline
+
+\family typewriter
+...
+\layout Standard
+
+will generate the following code:
+\layout Verse
+
+
+\family typewriter
+mov\SpecialChar ~
+\SpecialChar ~
+a,_i
+\newline
+rl\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+a
+\newline
+mov\SpecialChar ~
+\SpecialChar ~
+_i,a
+\layout Standard
+
+SDCC uses pattern matching on the parse tree to determine this operation.Variatio
+ns of this case will also be recognized as bit-rotation, i.e.:
+\layout Verse
+
+
+\family typewriter
+i = ((i >> 7) | (i << 1)); /* left-bit rotation */
+\layout Subsubsection
+
+Highest Order Bit
+\begin_inset LatexCommand \index{Highest Order Bit}
+
+\end_inset
+
+
+\layout Standard
+
+It is frequently required to obtain the highest order bit of an integral
+ type (long, int, short or char types).
+ SDCC recognizes the following expression to yield the highest order bit
+ and generates optimized code for it, e.g.:
+\layout Verse
+
+
+\family typewriter
+unsigned int gint;
+\newline
+
+\newline
+foo () {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+unsigned char hob;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+...
+
+\newline
+\SpecialChar ~
+\SpecialChar ~
+hob = (gint >> 15) & 1;
+\newline
+\SpecialChar ~
+\SpecialChar ~
+..
+
+\newline
+}
+\layout Standard
+
+will generate the following code:
+\layout Verse
+
+
+\family typewriter
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\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
+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
+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 ~
+ anl\SpecialChar ~
+\SpecialChar ~
+ a,#0x01
+\newline
+000F F5*02\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\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
+
+Variations of this case however will
+\emph on
+not
+\emph default
+ be recognized.
+ It is a standard C expression, so I heartily recommend this be the only
+ way to get the highest order bit, (it is portable).
+ Of course it will be recognized even if it is embedded in other expressions,
+ e.g.:
+\layout Verse
+
+
+\family typewriter
+xyz = gint + ((gint >> 15) & 1);
+\layout Standard
+
+will still be recognized.
+\layout Subsubsection
+
+Peephole Optimizer
+\begin_inset LatexCommand \index{Peephole optimizer}
+
+\end_inset
+
+
+\layout Standard
+
+The compiler uses a rule based, pattern matching and re-writing mechanism
+ for peep-hole optimization.
+ It is inspired by
+\emph on
+copt
+\emph default
+ a peep-hole optimizer by Christopher W.
+ Fraser (cwfraser@microsoft.com).
+ A default set of rules are compiled into the compiler, additional rules
+ may be added with the
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file
+\begin_inset LatexCommand \index{-\/-peep-file}
+
+\end_inset
+
+ <filename>
+\emph default
+ option.
+ The rule language is best illustrated with examples.
+\layout Verse
+
+
+\family typewriter
+replace {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+mov %1,a
+\newline
+\SpecialChar ~
+\SpecialChar ~
+mov a,%1
+\newline
+} by {
+\newline
+\SpecialChar ~
+\SpecialChar ~
+mov %1,a
+\newline
+}
+\layout Standard
+
+The above rule will change the following assembly
+\begin_inset LatexCommand \index{Assembler routines}
+
+\end_inset
+
+ sequence:
+\layout Verse
+
+
+\family typewriter
+mov r1,a
+\newline
+mov a,r1
+\layout Standard
+
+to
+\layout Verse
+
+
+\family typewriter
+mov r1,a
+\layout Standard
+
+Note: All occurrences of a
+\emph on
+%n
+\emph default
+ (pattern variable) must denote the same string.
+ With the above rule, the assembly sequence:
+\layout Verse
+
+
+\family typewriter
+mov r1,a
+\newline
+mov a,r2
+\layout Standard
+
+will remain unmodified.
+\newline
+
+\newline
+Other special case optimizations may be added by the user (via
+\emph on
+-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file option
+\emph default
+).
+ E.g.
+ some variants of the 8051 MCU allow only
+\family typewriter
+ajmp
+\family default
+ and
+\family typewriter
+acall
+\family default
+.
+ The following two rules will change all
+\family typewriter
+ljmp
+\family default
+ and
+\family typewriter
+lcall
+\family default
+ to
+\family typewriter
+ajmp
+\family default
+ and
+\family typewriter
+acall
+\layout Verse
+
+
+\family typewriter
+replace { lcall %1 } by { acall %1 }
+\newline
+replace { ljmp %1 } by { ajmp %1 }
+\layout Standard
+
+The
+\emph on
+inline-assembler code
+\emph default
+ is also passed through the peep hole optimizer, thus the peephole optimizer
+ can also be used as an assembly level macro expander.
+ The rules themselves are MCU dependent whereas the rule language infra-structur
+e is MCU independent.
+ Peephole optimization rules for other MCU can be easily programmed using
+ the rule language.
+\newline
+
+\newline
+The syntax for a rule is as follows:
+\layout Verse
+
+
+\family typewriter
+rule := replace [ restart ] '{' <assembly sequence> '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ '}' by '{' '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ <assembly sequence> '
+\backslash
+n'
+\newline
+\SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ \SpecialChar ~
+ '}' [if <functionName> ] '
+\backslash
+n'
+\layout Standard
+
+<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.
+ Currently implemented are
+\emph on
+labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
+ 24bitMode, portIsDS390, 24bitModeAndPortDS390
+\emph default
+and
+\emph on
+ notVolatile
+\emph default
+.
+\layout Standard
+
+I know this whole thing is a little kludgey, but maybe some day we will
+ have some better means.
+ If you are looking at this file, you will see the default rules that are
+ compiled into the compiler, you can add your own rules in the default set
+ there if you get tired of specifying the -
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-peep-file option.
+\layout Subsection
+
+Library Routines
+\emph on
+
+\layout Standard
+
+
+\emph on
+<pending: this is messy and incomplete>
+\emph default
+
+\layout Enumerate
+
+Compiler support routines (_gptrget, _mulint etc)
+\layout Enumerate
+
+Stdclib functions (puts, printf, strcat etc)
+\layout Enumerate
+
+Math functions (sin, pow, sqrt etc)
+\layout Standard
+
+Libraries
+\begin_inset LatexCommand \index{Libraries}
+
+\end_inset
+
+ included in SDCC should have a license at least as liberal as the GNU Lesser
+ General Public License
+\begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
+
+\end_inset
+
+
+\emph on
+LGPL
+\emph default
+.
+\layout Comment
+
+license statements for the libraries are missing.
+ sdcc/device/lib/ser_ir.c
+\layout Comment
+
+or _decdptr f.e.
+ come with a GPL (as opposed to LGPL) License - this will not be liberal
+ enough for many embedded programmers.
+\layout Subsection
+
+External Stack
+\begin_inset LatexCommand \label{sub:External-Stack}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{External stack}
+
+\end_inset
+
+
+\layout Standard
+
+The external stack (-
+\begin_inset ERT
+status Collapsed
+
+\layout Standard
+
+\backslash
+/
+\end_inset
+
+-xstack option
+\begin_inset LatexCommand \index{-\/-xstack}
+
+\end_inset
+
+) is located 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
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+ option, all parameters and local variables are allocated on the external
+ stack (note support libraries will need to be recompiled with the same
+ options).
+\layout Standard
+
+The compiler outputs the higher order address byte of the external ram segment
+ into PORT P2, 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
-;;\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- buffer point
+foo()
\newline
-;; g\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdbsrc-goto-sdcdb\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-Goto the SDCDB output buffer
+{
\newline
-;; t\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdbsrc-mode\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+...
+
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
+s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
+\newline
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-Toggles Sdcdbsrc mode (turns it off)
+...
+
\newline
-;;
+}
\newline
-;; C-c C-f\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdb-finish-from-src\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-SDCDB finish command
+struct s foo1 (struct s parms) /* invalid in SDCC although allowed in ANSI
+ */
\newline
-;;
+{
\newline
-;; C-x SPC\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
- sdcdb-break\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-Set break for line with point
+struct s rets;
\newline
-;; ESC t\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdbsrc-mode\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-Toggle Sdcdbsrc mode
+...
+
\newline
-;; ESC m\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
- sdcdbsrc-srcmode\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
-\SpecialChar ~
\SpecialChar ~
\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 ~
- Toggle list mode
+...
+
\newline
-;;
-\family default
+}
+\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
-\layout Section
-\pagebreak_top
-Other Processors
+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 Subsection
+Other Processors
+\layout Subsubsection
+
+MCS51 variants
+\begin_inset LatexCommand \index{MCS51 variants}
+
+\end_inset
+
+
+\layout Standard
+
+MCS51 processors are available from many vendors and come in many different
+ flavours.
+ While they might differ considerably in respect to Special Function Registers
+ the core MCS51 is usually not modified or is kept compatible.
+
+\layout Subsubsection*
+
+pdata access by SFR
+\layout Standard
+
+With the upcome of devices with internal xdata and flash memory devices
+ using port P2 as dedicated I/O port is becoming more popular.
+ Switching the high byte for pdata
+\begin_inset LatexCommand \index{pdata}
+
+\end_inset
+
+ access which was formerly done by port P2 is then achieved by a Special
+ Function Register.
+ In well-established MCS51 tradition the address of this
+\emph on
+sfr
+\emph default
+ is where the chip designers decided to put it.
+ As pdata addressing is used in the startup code for the initialization
+ of xdata variables a separate startup code should be used as described
+ in section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
+
+\end_inset
+
+.
+\layout Subsubsection*
+
+Other Features available by SFR
+\layout Standard
+
+Some MCS51 variants offer features like Double DPTR
+\begin_inset LatexCommand \index{DPTR}
+
+\end_inset
+
+, multiple DPTR, decrementing DPTR, 16x16 Multiply.
+ These are currently not used for the MCS51 port.
+ If you absolutely need them you can fall back to inline assembly or submit
+ a patch to SDCC.
+\layout Subsubsection
+
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
- unimplimented), and both float and bitfield support is missing.
- Apart from that the code generated is correct.
+SDCC can target both the Zilog
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ and the Nintendo Gameboy's Z80-like gbz80
+\begin_inset LatexCommand \index{GameBoy Z80}
+
+\end_inset
+
+.
+ The Z80 port is passed through the same
+\emph on
+regressions tests
+\begin_inset LatexCommand \index{Regression test}
+
+\end_inset
+
+
+\emph default
+ as MCS51 and DS390 ports, so floating point support, support for long variables
+ and bitfield support is fine.
\layout Standard
-As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c.
+As always, the code is the authoritative 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.
+ 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
+\layout Subsection
-Support
-\begin_inset LatexCommand \index{Support}
+Retargetting for other MCUs.
+\layout Standard
-\end_inset
+The issues for retargetting the compiler are far too numerous to be covered
+ by this document.
+ What follows is a brief description of each of the seven phases of the
+ compiler and its MCU dependency.
+\layout Itemize
+
+Parsing the source and building the annotated parse tree.
+ This phase is largely MCU independent (except for the language extensions).
+ Syntax & semantic checks are also done in this phase, along with some initial
+ optimizations like back patching labels and the pattern matching optimizations
+ like bit-rotation etc.
+\layout Itemize
+The second phase involves generating an intermediate code which can be easy
+ manipulated during the later phases.
+ This phase is entirely MCU independent.
+ The intermediate code generation assumes the target machine has unlimited
+ number of registers, and designates them with the name iTemp.
+ The compiler can be made to dump a human readable form of the code generated
+ by using the -
+\begin_inset ERT
+status Collapsed
\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 Subsection
+\backslash
+/
+\end_inset
-Reporting Bugs
-\begin_inset LatexCommand \index{Bugs}
+-dumpraw option.
+\layout Itemize
-\end_inset
+This phase does the bulk of the standard optimizations and is also MCU independe
+nt.
+ This phase can be broken down into several sub-phases:
+\newline
+\newline
+Break down intermediate code (iCode) into basic blocks.
+\newline
+Do control flow & data flow analysis on the basic blocks.
+\newline
+Do local common subexpression elimination, then global subexpression elimination
+\newline
+Dead code elimination
+\newline
+Loop optimizations
+\newline
+If loop optimizations caused any changes then do 'global subexpression eliminati
+on' and 'dead code elimination' again.
+\layout Itemize
-\begin_inset LatexCommand \index{Reporting Bugs}
+This phase determines the live-ranges; by live range I mean those iTemp
+ variables defined by the compiler that still survive after all the optimization
+s.
+ Live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
+ is essential for register allocation, since these computation determines
+ which of these iTemps will be assigned to registers, and for how long.
+\layout Itemize
-\layout Standard
+Phase five is register allocation.
+ There are two parts to this process.
+\newline
-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.
+\newline
+The first part I call 'register packing' (for lack of a better term).
+ In this case several MCU specific expression folding is done to reduce
+ register pressure.
+\newline
+
+\newline
+The second part is more MCU independent and deals with allocating registers
+ to the remaining live ranges.
+ A lot of MCU specific code does creep into this phase because of the limited
+ number of index registers available in the 8051.
+\layout Itemize
+
+The Code generation phase is (unhappily), entirely MCU dependent and very
+ little (if any at all) of this code can be reused for other MCU.
+ However the scheme for allocating a homogenized assembler operand for each
+ iCode operand may be reused.
+\layout Itemize
+
+As mentioned in the optimization section the peep-hole optimizer is rule
+ based system, which can reprogrammed for other MCUs.
\layout 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 Standard
Parsing the input source file and creating an AST (Annotated Syntax Tree
-\begin_inset LatexCommand \index{Annotated Syntax Tree}
+\begin_inset LatexCommand \index{Annotated syntax tree}
\end_inset
\layout Paragraph*
Register Allocation
-\begin_inset LatexCommand \index{Register Allocation}
+\begin_inset LatexCommand \index{Register allocation}
\end_inset
\layout Paragraph*
ICode Example
-\begin_inset LatexCommand \index{ICode Example}
+\begin_inset LatexCommand \index{iCode}
\end_inset
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.
if (something)
\layout Standard
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
[basic block 2]
\layout Standard
else
\layout Standard
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
+\SpecialChar ~
[basic block 3]
\layout Standard
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
projects / fw / sdcc / blobdiff