1 #LyX 1.3 created this file. For more info see http://www.lyx.org/
5 \pdfoptionpdfminorversion=3
7 pdftitle={SDCC Compiler User Guide},
8 pdfauthor={SDCC development team},
9 pdfsubject={installation, user manual},
10 pdfkeywords={68hc08 8032 8051 ansi c compiler assembler CPU DS390 embedded development free Floating Point Arithmetic Freescale GPL HC08 inline Intel ISO/IEC 9899:1990 Linux MAC OS X manual Maxim mcs51 Microchip microcontroller open source PIC Unix Windows Z80 Zilog},
11 pdfpagemode=UseOutlines,
13 linkcolor=blue] {hyperref}
17 \emergencystretch=30pt
22 \inputencoding default
25 \paperfontsize default
27 \papersize letterpaper
32 \use_numerical_citations 0
33 \paperorientation portrait
40 \paragraph_separation indent
42 \quotes_language swedish
50 Please note: double dashed longoptions (e.g.
51 --version) are written this way: -
65 three consecutive dashes simply result in a long resp.
69 Architecture specific stuff (like memory models, code examples) should maybe
73 into seperate sections/chapters/appendices (it is hard to document PIC or
77 a 8051 centered document) - for now simply add.
80 SDCC Compiler User Guide
94 The above strings enclosed in $ are automatically updated by Subversion
98 \begin_inset LatexCommand \tableofcontents{}
131 ompiler) is an open source, retargettable, optimizing ANSI-C compiler by
136 designed for 8 bit Microprocessors.
137 The current version targets Intel MCS51 based Microprocessors (8031, 8032,
139 \begin_inset LatexCommand \index{8031, 8032, 8051, 8052, mcs51 CPU}
143 , etc.), Dallas DS80C390 variants, Freescale (formerly Motorola) HC08 and
144 Zilog Z80 based MCUs.
145 It can be retargeted for other microprocessors, support for Microchip PIC,
146 Atmel AVR is under development.
147 The entire source code for the compiler is distributed under GPL.
149 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
154 \begin_inset LatexCommand \index{aslink}
158 , an open source retargetable assembler & linker.
159 SDCC has extensive language extensions suitable for utilizing various microcont
160 rollers and underlying hardware effectively.
165 In addition to the MCU specific optimizations SDCC also does a host of standard
169 global sub expression elimination,
172 loop optimizations (loop invariant, strength reduction of induction variables
176 constant folding & propagation,
182 dead code elimination
192 For the back-end SDCC uses a global register allocation scheme which should
193 be well suited for other 8 bit MCUs.
198 The peep hole optimizer uses a rule based substitution mechanism which is
204 Supported data-types are:
209 <lyxtabular version="3" rows="8" columns="5">
211 <column alignment="center" valignment="top" leftline="true" width="0">
212 <column alignment="center" valignment="top" leftline="true" width="0">
213 <column alignment="center" valignment="top" leftline="true" width="0">
214 <column alignment="center" valignment="top" leftline="true" width="0">
215 <column alignment="block" valignment="top" leftline="true" rightline="true" width="20text%">
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217 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
225 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
233 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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259 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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291 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
301 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
309 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
317 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
325 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
333 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
343 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
351 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
359 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
367 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
375 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
385 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
393 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
401 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
409 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
417 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
426 <row topline="true" bottomline="true">
427 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
435 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
443 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
451 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
456 -2.147.483.648, +2.147.483.647
459 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
468 <row topline="true" bottomline="true">
469 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
477 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
485 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
493 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
500 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
518 <row topline="true" bottomline="true">
519 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
527 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
535 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
543 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
550 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
564 The compiler also allows
566 inline assembler code
568 to be embedded anywhere in a function.
569 In addition, routines developed in assembly can also be called.
573 SDCC also provides an option (-
583 -cyclomatic) to report the relative complexity of a function.
584 These functions can then be further optimized, or hand coded in assembly
590 SDCC also comes with a companion source level debugger SDCDB, the debugger
591 currently uses ucSim a freeware simulator for 8051 and other micro-controllers.<
595 The latest version can be downloaded from
596 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
606 Please note: the compiler will probably always be some steps ahead of this
611 \begin_inset LatexCommand \index{Status of documentation}
621 Obviously this has pros and cons
630 All packages used in this compiler system are
638 ; source code for all the sub-packages (pre-processor, assemblers, linkers
639 etc) is distributed with the package.
640 This documentation is maintained using a freeware word processor (LyX).
642 This program is free software; you can redistribute it and/or modify it
643 under the terms of the GNU General Public License
644 \begin_inset LatexCommand \index{GNU General Public License, GPL}
648 as published by the Free Software Foundation; either version 2, or (at
649 your option) any later version.
650 This program is distributed in the hope that it will be useful, but WITHOUT
651 ANY WARRANTY; without even the implied warranty
652 \begin_inset LatexCommand \index{warranty}
656 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
657 See the GNU General Public License for more details.
658 You should have received a copy of the GNU General Public License along
659 with this program; if not, write to the Free Software Foundation, 59 Temple
660 Place - Suite 330, Boston, MA 02111-1307, USA.
661 In other words, you are welcome to use, share and improve this program.
662 You are forbidden to forbid anyone else to use, share and improve what
664 Help stamp out software-hoarding!
667 Typographic conventions
668 \begin_inset LatexCommand \index{Typographic conventions}
675 Throughout this manual, we will use the following convention.
676 Commands you have to type in are printed in
684 Code samples are printed in
689 Interesting items and new terms are printed in
695 \begin_inset LatexCommand \label{sec:Compatibility-with-previous}
699 with previous versions
700 \begin_inset LatexCommand \index{Compatibility with previous versions}
707 This version has numerous bug fixes compared with the previous version.
708 But we also introduced some incompatibilities with older versions.
709 Not just for the fun of it, but to make the compiler more stable, efficient
711 \begin_inset LatexCommand \index{ANSI-compliance}
716 \begin_inset LatexCommand \ref{sub:ANSI-Compliance}
720 for ANSI-Compliance).
726 short is now equivalent to int (16 bits), it used to be equivalent to char
727 (8 bits) which is not ANSI compliant.
730 the default directory for gcc-builds where include, library and documentation
731 files are stored is now in /usr/local/share.
734 char type parameters to vararg
735 \begin_inset LatexCommand \index{vararg, va\_arg}
739 functions are casted to int unless explicitly casted
740 \begin_inset Marginal
767 will push a as an int and as a char resp.
780 -regextend has been removed.
793 -noregparms has been removed.
806 -stack-after-data has been removed.
810 \begin_inset LatexCommand \index{bit}
815 \begin_inset LatexCommand \index{sbit}
820 \begin_inset LatexCommand \index{\_\_sbit}
824 types now consistently behave like the C99 _Bool type with respect to type
826 \begin_inset LatexCommand \index{type conversion}
831 \begin_inset LatexCommand \index{type promotion}
836 The most common incompatibility resulting from this change is related to
838 \begin_inset LatexCommand \index{Bit toggling}
853 \begin_inset LatexCommand \index{\~\/ Operator}
857 b; /* equivalent to b=1 instead of toggling b */
858 \begin_inset Marginal
873 b = !b; /* toggles b */
877 In previous versions, both forms would have toggled the bit.
882 <pending: more incompatibilities?>
888 What do you need before you start installation of SDCC? A computer, and
890 The preferred method of installation is to compile SDCC from source using
892 For Windows some pre-compiled binary distributions are available for your
894 You should have some experience with command line tools and compiler use.
900 The SDCC home page at
901 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
905 is a great place to find distribution sets.
906 You can also find links to the user mailing lists that offer help or discuss
907 SDCC with other SDCC users.
908 Web links to other SDCC related sites can also be found here.
909 This document can be found in the DOC directory of the source package as
911 A pdf version of this document is available at
912 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}
917 Some of the other tools (simulator and assembler) included with SDCC contain
918 their own documentation and can be found in the source distribution.
919 If you want the latest unreleased software, the complete source package
920 is available directly from Subversion on https://svn.sourceforge.net/svnroot/sdcc
924 Wishes for the future
927 There are (and always will be) some things that could be done.
928 Here are some I can think of:
935 char KernelFunction3(char p) at 0x340;
943 \begin_inset LatexCommand \index{code banking (limited support)}
953 If you can think of some more, please see the section
954 \begin_inset LatexCommand \ref{sub:Requesting-Features}
958 about filing feature requests
959 \begin_inset LatexCommand \index{Requesting features}
964 \begin_inset LatexCommand \index{Feature request}
974 \begin_inset LatexCommand \index{Installation}
981 For most users it is sufficient to skip to either section
982 \begin_inset LatexCommand \ref{sub:Building-SDCC-on-Linux}
987 \begin_inset LatexCommand \ref{sub:Windows-Install}
992 More detailed instructions follow below.
996 \begin_inset LatexCommand \index{Options SDCC configuration}
1003 The install paths, search paths and other options are defined when running
1005 The defaults can be overridden by:
1007 \labelwidthstring 00.00.0000
1019 -prefix see table below
1021 \labelwidthstring 00.00.0000
1033 -exec_prefix see table below
1035 \labelwidthstring 00.00.0000
1047 -bindir see table below
1049 \labelwidthstring 00.00.0000
1061 -datadir see table below
1065 \labelwidthstring 00.00.0000
1069 docdir environment variable, see table below
1071 \labelwidthstring 00.00.0000
1075 include_dir_suffix environment variable, see table below
1077 \labelwidthstring 00.00.0000
1081 lib_dir_suffix environment variable, see table below
1083 \labelwidthstring 00.00.0000
1087 sdccconf_h_dir_separator environment variable, either / or
1092 This character will only be used in sdccconf.h; don't forget it's a C-header,
1093 therefore a double-backslash is needed there.
1097 \labelwidthstring 00.00.0000
1109 -disable-mcs51-port Excludes the Intel mcs51 port
1111 \labelwidthstring 00.00.0000
1123 -disable-gbz80-port Excludes the Gameboy gbz80 port
1125 \labelwidthstring 00.00.0000
1137 -disable-z80-port Excludes the z80 port
1139 \labelwidthstring 00.00.0000
1151 -disable-avr-port Excludes the AVR port
1153 \labelwidthstring 00.00.0000
1165 -disable-ds390-port Excludes the DS390 port
1167 \labelwidthstring 00.00.0000
1179 -disable-hc08-port Excludes the HC08 port
1181 \labelwidthstring 00.00.0000
1193 -disable-pic-port Excludes the PIC port
1195 \labelwidthstring 00.00.0000
1207 -disable-xa51-port Excludes the XA51 port
1209 \labelwidthstring 00.00.0000
1221 -disable-ucsim Disables configuring and building of ucsim
1223 \labelwidthstring 00.00.0000
1235 -disable-device-lib Disables automatically building device libraries
1237 \labelwidthstring 00.00.0000
1249 -disable-packihx Disables building packihx
1253 \labelwidthstring 00.00.0000
1265 -enable-doc Build pdf, html and txt files from the lyx sources
1267 \labelwidthstring 00.00.0000
1279 -enable-libgc Use the Bohem memory allocator.
1280 Lower runtime footprint.
1283 Furthermore the environment variables CC, CFLAGS, ...
1284 the tools and their arguments can be influenced.
1285 Please see `configure -
1295 -help` and the man/info pages of `configure` for details.
1299 The names of the standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB,
1300 STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
1301 NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
1302 At the moment it's not possible to change the default settings (it was
1303 simply never required).
1307 These configure options are compiled into the binaries, and can only be
1308 changed by rerunning 'configure' and recompiling SDCC.
1309 The configure options are written in
1313 to distinguish them from run time environment variables (see section search
1319 \begin_inset Quotes sld
1323 \begin_inset Quotes srd
1326 are used by the SDCC team to build the official Win32 binaries.
1327 The SDCC team uses Mingw32 to build the official Windows binaries, because
1334 a gcc compiler and last but not least
1337 the binaries can be built by cross compiling on Sourceforge's compile farm.
1340 See the examples, how to pass the Win32 settings to 'configure'.
1341 The other Win32 builds using Borland, VC or whatever don't use 'configure',
1342 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
1353 \begin_inset Tabular
1354 <lyxtabular version="3" rows="8" columns="3">
1356 <column alignment="block" valignment="top" leftline="true" width="0in">
1357 <column alignment="block" valignment="top" leftline="true" width="0in">
1358 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1359 <row topline="true" bottomline="true">
1360 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1368 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1376 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1385 <row topline="true">
1386 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1396 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1404 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1415 <row topline="true">
1416 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1426 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1436 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1447 <row topline="true">
1448 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1458 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1470 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1485 <row topline="true">
1486 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1496 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1508 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1519 <row topline="true">
1520 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1530 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1542 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1557 <row topline="true">
1558 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1568 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1576 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1585 <row topline="true" bottomline="true">
1586 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1596 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1604 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1622 'configure' also computes relative paths.
1623 This is needed for full relocatability of a binary package and to complete
1624 search paths (see section search paths below):
1630 \begin_inset Tabular
1631 <lyxtabular version="3" rows="4" columns="3">
1633 <column alignment="block" valignment="top" leftline="true" width="0in">
1634 <column alignment="block" valignment="top" leftline="true" width="0in">
1635 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1636 <row topline="true" bottomline="true">
1637 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1645 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1653 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1662 <row topline="true" bottomline="true">
1663 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1673 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1681 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1690 <row bottomline="true">
1691 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1701 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1709 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1718 <row bottomline="true">
1719 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1729 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1737 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1770 \begin_inset Quotes srd
1774 \begin_inset Quotes srd
1788 \begin_inset Quotes srd
1792 \begin_inset Quotes srd
1820 To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
1829 \begin_inset Quotes srd
1832 i586-mingw32msvc-gcc
1833 \begin_inset Quotes srd
1837 \begin_inset Quotes srd
1840 i586-mingw32msvc-g++
1841 \begin_inset Quotes srd
1849 \begin_inset Quotes srd
1852 i586-mingw32msvc-ranlib
1853 \begin_inset Quotes srd
1861 \begin_inset Quotes srd
1864 i586-mingw32msvc-strip
1865 \begin_inset Quotes srd
1883 \begin_inset Quotes srd
1887 \begin_inset Quotes srd
1905 \begin_inset Quotes srd
1909 \begin_inset Quotes srd
1917 \begin_inset Quotes srd
1921 \begin_inset Quotes srd
1929 \begin_inset Quotes srd
1933 \begin_inset Quotes srd
1941 \begin_inset Quotes srd
1945 \begin_inset Quotes srd
1952 sdccconf_h_dir_separator=
1953 \begin_inset Quotes srd
1965 \begin_inset Quotes srd
1996 -host=i586-mingw32msvc
2010 -build=unknown-unknown-linux-gnu
2014 \begin_inset Quotes sld
2018 \begin_inset Quotes srd
2021 compile on Cygwin for Mingw32 (see also sdcc/support/scripts/sdcc_cygwin_mingw32
2040 \begin_inset Quotes srd
2044 \begin_inset Quotes srd
2062 \begin_inset Quotes srd
2066 \begin_inset Quotes srd
2074 \begin_inset Quotes srd
2078 \begin_inset Quotes srd
2086 \begin_inset Quotes srd
2090 \begin_inset Quotes srd
2098 \begin_inset Quotes srd
2102 \begin_inset Quotes srd
2109 sdccconf_h_dir_separator=
2110 \begin_inset Quotes srd
2122 \begin_inset Quotes srd
2130 \begin_inset Quotes srd
2134 \begin_inset Quotes srd
2142 \begin_inset Quotes srd
2146 \begin_inset Quotes srd
2152 'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
2163 -C' turns on caching, which gives a little bit extra speed.
2164 However if options are changed, it can be necessary to delete the config.cache
2169 \begin_inset LatexCommand \label{sub:Install-paths}
2174 \begin_inset LatexCommand \index{Install paths}
2180 \added_space_top medskip \align center
2182 \begin_inset Tabular
2183 <lyxtabular version="3" rows="5" columns="4">
2185 <column alignment="left" valignment="top" leftline="true" width="0">
2186 <column alignment="left" valignment="top" leftline="true" width="0">
2187 <column alignment="left" valignment="top" leftline="true" width="0">
2188 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
2189 <row topline="true" bottomline="true">
2190 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2200 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2210 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2220 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2231 <row topline="true">
2232 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2240 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2250 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2258 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2271 <row topline="true">
2272 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2280 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2287 $DATADIR/ $INCLUDE_DIR_SUFFIX
2290 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2295 /usr/local/share/sdcc/include
2298 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2311 <row topline="true">
2312 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2320 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2327 $DATADIR/$LIB_DIR_SUFFIX
2330 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2335 /usr/local/share/sdcc/lib
2338 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2351 <row topline="true" bottomline="true">
2352 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2360 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2370 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2375 /usr/local/share/sdcc/doc
2378 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2400 *compiler, preprocessor, assembler, and linker
2406 is auto-appended by the compiler, e.g.
2407 small, large, z80, ds390 etc
2410 The install paths can still be changed during `make install` with e.g.:
2413 make install prefix=$(HOME)/local/sdcc
2416 Of course this doesn't change the search paths compiled into the binaries.
2420 Moreover the install path can be changed by defining DESTDIR
2421 \begin_inset LatexCommand \index{DESTDIR}
2428 make install DESTDIR=$(HOME)/sdcc.rpm/
2431 Please note that DESTDIR must have a trailing slash!
2435 \begin_inset LatexCommand \label{sub:Search-Paths}
2440 \begin_inset LatexCommand \index{Search path}
2447 Some search paths or parts of them are determined by configure variables
2452 , see section above).
2453 Further search paths are determined by environment variables during runtime.
2456 The paths searched when running the compiler are as follows (the first catch
2462 Binary files (preprocessor, assembler and linker)
2468 \begin_inset Tabular
2469 <lyxtabular version="3" rows="4" columns="3">
2471 <column alignment="block" valignment="top" leftline="true" width="0in">
2472 <column alignment="block" valignment="top" leftline="true" width="0in">
2473 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2474 <row topline="true" bottomline="true">
2475 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2483 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2491 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2500 <row topline="true">
2501 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2511 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2519 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2530 <row topline="true">
2531 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2536 Path of argv[0] (if available)
2539 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2547 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2556 <row topline="true" bottomline="true">
2557 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2565 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2573 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2598 \begin_inset Tabular
2599 <lyxtabular version="3" rows="6" columns="3">
2601 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2602 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2603 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2604 <row topline="true" bottomline="true">
2605 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2613 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2621 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2630 <row topline="true">
2631 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2649 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2667 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2686 <row topline="true">
2687 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2695 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2703 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2712 <row topline="true">
2713 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2727 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2739 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2750 <row topline="true">
2751 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2769 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2819 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2832 <row topline="true" bottomline="true">
2833 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2849 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2854 /usr/local/share/sdcc/
2859 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2887 -nostdinc disables the last two search paths.
2897 With the exception of
2898 \begin_inset Quotes sld
2912 \begin_inset Quotes srd
2919 is auto-appended by the compiler (e.g.
2920 small, large, z80, ds390 etc.).
2927 \begin_inset Tabular
2928 <lyxtabular version="3" rows="6" columns="3">
2930 <column alignment="block" valignment="top" leftline="true" width="1.7in">
2931 <column alignment="block" valignment="top" leftline="true" width="1.2in">
2932 <column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
2933 <row topline="true" bottomline="true">
2934 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2942 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2950 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2959 <row topline="true">
2960 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2978 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2996 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3015 <row topline="true">
3016 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3028 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3040 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3055 <row topline="true">
3056 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3067 $LIB_DIR_SUFFIX/<model>
3070 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3084 <cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3101 <row topline="true">
3102 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3117 $LIB_DIR_SUFFIX/<model>
3120 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3173 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3229 <row topline="true" bottomline="true">
3230 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3239 $LIB_DIR_SUFFIX/<model>
3242 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3247 /usr/local/share/sdcc/
3254 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3272 Don't delete any of the stray spaces in the table above without checking
3273 the HTML output (last line)!
3289 -nostdlib disables the last two search paths.
3293 \begin_inset LatexCommand \index{Building SDCC}
3300 Building SDCC on Linux
3301 \begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}
3310 Download the source package
3312 either from the SDCC Subversion repository or from the nightly snapshots
3314 , it will be named something like sdcc
3325 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
3334 Bring up a command line terminal, such as xterm.
3339 Unpack the file using a command like:
3342 "tar -xvzf sdcc.src.tar.gz
3347 , this will create a sub-directory called sdcc with all of the sources.
3350 Change directory into the main SDCC directory, for example type:
3367 This configures the package for compilation on your system.
3383 All of the source packages will compile, this can take a while.
3399 This copies the binary executables, the include files, the libraries and
3400 the documentation to the install directories.
3401 Proceed with section
3402 \begin_inset LatexCommand \ref{sec:Testing-the-SDCC}
3409 Building SDCC on OSX 2.x
3412 Follow the instruction for Linux.
3416 On OSX 2.x it was reported, that the default gcc (version 3.1 20020420 (prerelease
3417 )) fails to compile SDCC.
3418 Fortunately there's also gcc 2.9.x installed, which works fine.
3419 This compiler can be selected by running 'configure' with:
3422 ./configure CC=gcc2 CXX=g++2
3425 Cross compiling SDCC on Linux for Windows
3428 With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
3429 See section 'Configure Options'.
3432 Building SDCC using Cygwin and Mingw32
3435 For building and installing a Cygwin executable follow the instructions
3441 \begin_inset Quotes sld
3445 \begin_inset Quotes srd
3448 Win32-binary can be built, which will not need the Cygwin-DLL.
3449 For the necessary 'configure' options see section 'configure options' or
3450 the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
3454 In order to install Cygwin on Windows download setup.exe from
3455 \begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}
3461 \begin_inset Quotes sld
3464 default text file type
3465 \begin_inset Quotes srd
3469 \begin_inset Quotes sld
3473 \begin_inset Quotes srd
3476 and download/install at least the following packages.
3477 Some packages are selected by default, others will be automatically selected
3478 because of dependencies with the manually selected packages.
3479 Never deselect these packages!
3488 gcc ; version 3.x is fine, no need to use the old 2.9x
3491 binutils ; selected with gcc
3497 rxvt ; a nice console, which makes life much easier under windoze (see below)
3500 man ; not really needed for building SDCC, but you'll miss it sooner or
3504 less ; not really needed for building SDCC, but you'll miss it sooner or
3508 svn ; only if you use Subversion access
3511 If you want to develop something you'll need:
3514 python ; for the regression tests
3517 gdb ; the gnu debugger, together with the nice GUI
3518 \begin_inset Quotes sld
3522 \begin_inset Quotes srd
3528 openssh ; to access the CF or commit changes
3531 autoconf and autoconf-devel ; if you want to fight with 'configure', don't
3532 use autoconf-stable!
3535 rxvt is a nice console with history.
3536 Replace in your cygwin.bat the line
3555 rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
3558 -bg black -fg white -geometry 100x65 -e bash -
3571 Text selected with the mouse is automatically copied to the clipboard, pasting
3572 works with shift-insert.
3576 The other good tip is to make sure you have no //c/-style paths anywhere,
3577 use /cygdrive/c/ instead.
3578 Using // invokes a network lookup which is very slow.
3580 \begin_inset Quotes sld
3584 \begin_inset Quotes srd
3587 is too long, you can change it with e.g.
3593 SDCC sources use the unix line ending LF.
3594 Life is much easier, if you store the source tree on a drive which is mounted
3596 And use an editor which can handle LF-only line endings.
3597 Make sure not to commit files with windows line endings.
3598 The tabulator spacing
3599 \begin_inset LatexCommand \index{tabulator spacing (8 columns)}
3603 used in the project is 8.
3604 Although a tabulator spacing of 8 is a sensible choice for programmers
3605 (it's a power of 2 and allows to display 8/16 bit signed variables without
3606 loosing columns) the plan is to move towards using only spaces in the source.
3609 Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
3614 Download the source package
3616 either from the SDCC Subversion repository or from the
3617 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
3623 , it will be named something like sdcc
3630 SDCC is distributed with all the projects, workspaces, and files you need
3631 to build it using Visual C++ 6.0/NET (except for SDCDB and ucSim).
3632 The workspace name is 'sdcc.dsw'.
3633 Please note that as it is now, all the executables are created in a folder
3637 Once built you need to copy the executables from sdcc
3641 bin before running SDCC.
3646 WARNING: Visual studio is very picky with line terminations; it expects
3647 the 0x0d, 0x0a DOS style line endings, not the 0x0a Unix style line endings.
3648 When using the Subversion repository it's easiest to configure the svn
3649 client to convert automatically for you.
3650 If however you are getting a message such as "This makefile was not generated
3651 by Developer Studio etc.
3653 \begin_inset Quotes srd
3656 when opening the sdcc.dsw workspace or any of the *.dsp projects, then you
3657 need to convert the Unix style line endings to DOS style line endings.
3658 To do so you can use the
3659 \begin_inset Quotes sld
3663 \begin_inset Quotes srd
3666 utility freely available on the internet.
3667 Doug Hawkins reported in the sdcc-user list that this works:
3675 SDCC> unix2dos sdcc.dsw
3681 SDCC> for /R %I in (*.dsp) do @unix2dos "%I"
3685 In order to build SDCC with MSVC you need win32 executables of bison.exe,
3686 flex.exe, and gawk.exe.
3687 One good place to get them is
3688 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
3696 Download the file UnxUtils
3697 \begin_inset LatexCommand \index{UnxUtils}
3702 Now you have to install the utilities and setup MSVC so it can locate the
3704 Here there are two alternatives (choose one!):
3711 a) Extract UnxUtils.zip to your C:
3713 hard disk PRESERVING the original paths, otherwise bison won't work.
3714 (If you are using WinZip make certain that 'Use folder names' is selected)
3718 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3719 in 'Show directories for:' select 'Executable files', and in the directories
3720 window add a new path: 'C:
3730 (As a side effect, you get a bunch of Unix utilities that could be useful,
3731 such as diff and patch.)
3738 This one avoids extracting a bunch of files you may not use, but requires
3743 a) Create a directory were to put the tools needed, or use a directory already
3751 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
3752 to such directory WITHOUT preserving the original paths.
3753 (If you are using WinZip make certain that 'Use folder names' is not selected)
3757 c) Rename bison.exe to '_bison.exe'.
3761 d) Create a batch file 'bison.bat' in 'C:
3765 ' and add these lines:
3785 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
3789 Steps 'c' and 'd' are needed because bison requires by default that the
3790 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
3791 '/usr/local/share/' I think.
3792 So it is necessary to tell bison where those files are located if they
3793 are not in such directory.
3794 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
3798 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3799 in 'Show directories for:' select 'Executable files', and in the directories
3800 window add a new path: 'c:
3803 Note that you can use any other path instead of 'c:
3805 util', even the path where the Visual C++ tools are, probably: 'C:
3809 Microsoft Visual Studio
3814 So you don't have to execute step 'e' :)
3818 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
3819 the executables from sdcc
3823 bin, and you can compile using SDCC.
3826 Building SDCC Using Borland
3829 From the sdcc directory, run the command "make -f Makefile.bcc".
3830 This should regenerate all the .exe files in the bin directory except for
3834 If you modify any source files and need to rebuild, be aware that the dependenci
3835 es may not be correctly calculated.
3836 The safest option is to delete all .obj files and run the build again.
3837 From a Cygwin BASH prompt, this can easily be done with the command (be
3838 sure you are in the sdcc directory):
3848 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
3850 ) -print -exec rm {}
3859 or on Windows NT/2000/XP from the command prompt with the command:
3866 del /s *.obj *.lib *.rul
3869 from the sdcc directory.
3872 Windows Install Using a ZIP Package
3875 Download the binary zip package from
3876 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3880 and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
3881 This should unpack to a group of sub-directories.
3882 An example directory structure after unpacking the mingw32 package is:
3887 bin for the executables, c:
3895 lib for the include and libraries.
3898 Adjust your environment variable PATH to include the location of the bin
3899 directory or start sdcc using the full path.
3902 Windows Install Using the Setup Program
3903 \begin_inset LatexCommand \label{sub:Windows-Install}
3910 Download the setup program
3912 sdcc-x.y.z-setup.exe
3914 for an official release from
3917 \begin_inset LatexCommand \url{http://sf.net/project/showfiles.php?group_id=599}
3921 or a setup program for one of the snapshots
3923 sdcc-yyyymmdd-xxxx-setup.exe
3926 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3931 A windows typical installer will guide you through the installation process.
3935 \begin_inset LatexCommand \index{VPATH}
3942 SDCC supports the VPATH feature provided by configure and make.
3943 It allows to separate the source and build trees.
3975 tar -xzf sdcc.src.tar.gz\SpecialChar ~
3976 # extract source to directory sdcc
3981 mkdir sdcc.build\SpecialChar ~
3990 # put output in sdcc.build
4000 ../sdcc/configure\SpecialChar ~
4008 # configure is doing all the magic!
4020 will create the directory tree will all the necessary Makefiles in ~/sdcc.build.
4021 It automagically computes the variables srcdir, top_srcdir and top_buildir
4027 the generated files will be in ~/sdcc.build, while the source files stay
4030 This is not only usefull for building different binaries, e.g.
4031 when cross compiling.
4032 It also gives you a much better overview in the source tree when all the
4033 generated files are not scattered between the source files.
4034 And the best thing is: if you want to change a file you can leave the original
4035 file untouched in the source directory.
4036 Simply copy it to the build directory, edit it, enter `make clean`, `rm
4037 Makefile.dep` and `make`.
4042 will do the rest for you!
4045 Building the Documentation
4058 -enable-doc to the configure arguments to build the documentation together
4059 with all the other stuff.
4060 You will need several tools (LyX, LaTeX, LaTeX2HTML, pdflatex, dvipdf,
4061 dvips and makeindex) to get the job done.
4062 Another possibility is to change to the doc directory and to type
4066 \begin_inset Quotes srd
4070 \begin_inset Quotes srd
4077 You're invited to make changes and additions to this manual (sdcc/doc/sdccman.ly
4080 \begin_inset LatexCommand \url{http://www.lyx.org}
4084 as editor is straightforward.
4085 Prebuilt documentation in html and pdf format is available from
4086 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
4093 Reading the Documentation
4094 \begin_inset LatexCommand \index{Documentation}
4101 Currently reading the document in pdf format is recommended, as for unknown
4102 reason the hyperlinks are working there whereas in the html version they
4109 If you should know why please drop us a note
4115 You'll find the pdf version
4116 \begin_inset LatexCommand \index{PDF version of this document}
4121 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.pdf}
4129 \begin_inset LatexCommand \index{HTML version of this document}
4134 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.html/index.html}
4140 This documentation is in some aspects different from a commercial documentation:
4144 It tries to document SDCC for several processor architectures in one document
4145 (commercially these probably would be separate documents/products).
4147 \begin_inset LatexCommand \index{Status of documentation}
4151 currently matches SDCC for mcs51 and DS390 best and does give too few informati
4153 Z80, PIC14, PIC16 and HC08.
4156 There are many references pointing away from this documentation.
4157 Don't let this distract you.
4159 was a reference like
4160 \begin_inset LatexCommand \url{http://www.opencores.org}
4164 together with a statement
4165 \begin_inset Quotes sld
4168 some processors which are targetted by SDCC can be implemented in a
4185 \begin_inset LatexCommand \index{FPGA (field programmable gate array)}
4190 \begin_inset Quotes srd
4194 \begin_inset LatexCommand \url{http://sf.net/projects/fpgac}
4199 \begin_inset LatexCommand \index{FpgaC ((subset of) C to FPGA compiler)}
4204 \begin_inset Quotes sld
4207 have you ever heard of an open source compiler that compiles a subset of
4209 \begin_inset Quotes srd
4212 we expect you to have a quick look there and come back.
4213 If you read this you are on the right track.
4216 Some sections attribute more space to problems, restrictions and warnings
4217 than to the solution.
4220 The installation section and the section about the debugger is intimidating.
4223 There are still lots of typos and there are more different writing styles
4227 Testing the SDCC Compiler
4228 \begin_inset LatexCommand \label{sec:Testing-the-SDCC}
4235 The first thing you should do after installing your SDCC compiler is to
4251 \begin_inset LatexCommand \index{version}
4258 at the prompt, and the program should run and output its version like:
4263 SDCC : mcs51/z80/avr/ds390/pic16/pic14/ds400/hc08 2.5.6 #4169 (May 8 2006)
4267 If it doesn't run, or gives a message about not finding sdcc program, then
4268 you need to check over your installation.
4269 Make sure that the sdcc bin directory is in your executable search path
4270 defined by the PATH environment setting (
4275 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4282 Install trouble-shooting for suggestions
4285 Make sure that the sdcc program is in the bin folder, if not perhaps something
4286 did not install correctly.
4294 is commonly installed as described in section
4295 \begin_inset Quotes sld
4298 Install and search paths
4299 \begin_inset Quotes srd
4308 Make sure the compiler works on a very simple example.
4309 Type in the following test.c program using your favorite
4335 Compile this using the following command:
4344 If all goes well, the compiler will generate a test.asm and test.rel file.
4345 Congratulations, you've just compiled your first program with SDCC.
4346 We used the -c option to tell SDCC not to link the generated code, just
4347 to keep things simple for this step.
4355 The next step is to try it with the linker.
4365 If all goes well the compiler will link with the libraries and produce
4366 a test.ihx output file.
4371 (no test.ihx, and the linker generates warnings), then the problem is most
4380 usr/local/share/sdcc/lib directory
4387 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4394 Install trouble-shooting for suggestions).
4402 The final test is to ensure
4410 header files and libraries.
4411 Edit test.c and change it to the following:
4428 strcpy(str1, "testing");
4435 Compile this by typing
4442 This should generate a test.ihx output file, and it should give no warnings
4443 such as not finding the string.h file.
4444 If it cannot find the string.h file, then the problem is that
4448 cannot find the /usr/local/share/sdcc/include directory
4455 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4462 Install trouble-shooting section for suggestions).
4480 \begin_inset LatexCommand \index{-\/-print-search-dirs}
4484 to find exactly where SDCC is looking for the include and lib files.
4487 Install Trouble-shooting
4488 \begin_inset LatexCommand \label{sub:Install-Trouble-shooting}
4493 \begin_inset LatexCommand \index{Install trouble-shooting}
4500 If SDCC does not build correctly
4503 A thing to try is starting from scratch by unpacking the .tgz source package
4504 again in an empty directory.
4512 ./configure 2>&1 | tee configure.log
4526 make 2>&1 | tee make.log
4533 If anything goes wrong, you can review the log files to locate the problem.
4534 Or a relevant part of this can be attached to an email that could be helpful
4535 when requesting help from the mailing list.
4539 \begin_inset Quotes sld
4543 \begin_inset Quotes srd
4550 \begin_inset Quotes sld
4554 \begin_inset Quotes srd
4557 command is a script that analyzes your system and performs some configuration
4558 to ensure the source package compiles on your system.
4559 It will take a few minutes to run, and will compile a few tests to determine
4560 what compiler features are installed.
4564 \begin_inset Quotes sld
4568 \begin_inset Quotes srd
4574 This runs the GNU make tool, which automatically compiles all the source
4575 packages into the final installed binary executables.
4579 \begin_inset Quotes sld
4583 \begin_inset Quotes erd
4589 This will install the compiler, other executables libraries and include
4590 files into the appropriate directories.
4592 \begin_inset LatexCommand \ref{sub:Install-paths}
4598 \begin_inset LatexCommand \ref{sub:Search-Paths}
4603 about install and search paths.
4605 On most systems you will need super-user privileges to do this.
4611 SDCC is not just a compiler, but a collection of tools by various developers.
4612 These include linkers, assemblers, simulators and other components.
4613 Here is a summary of some of the components.
4614 Note that the included simulator and assembler have separate documentation
4615 which you can find in the source package in their respective directories.
4616 As SDCC grows to include support for other processors, other packages from
4617 various developers are included and may have their own sets of documentation.
4621 You might want to look at the files which are installed in <installdir>.
4622 At the time of this writing, we find the following programs for gcc-builds:
4626 In <installdir>/bin:
4629 sdcc - The compiler.
4632 sdcpp - The C preprocessor.
4635 asx8051 - The assembler for 8051 type processors.
4642 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
4645 aslink -The linker for 8051 type processors.
4652 link-gbz80 - The Z80 and GameBoy Z80 linkers.
4655 s51 - The ucSim 8051 simulator.
4658 sdcdb - The source debugger.
4661 packihx - A tool to pack (compress) Intel hex files.
4664 In <installdir>/share/sdcc/include
4670 In <installdir>/share/sdcc/lib
4673 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
4677 In <installdir>/share/sdcc/doc
4683 As development for other processors proceeds, this list will expand to include
4684 executables to support processors like AVR, PIC, etc.
4690 This is the actual compiler, it in turn uses the c-preprocessor and invokes
4691 the assembler and linkage editor.
4694 sdcpp - The C-Preprocessor
4698 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
4702 is a modified version of the GNU cpp
4703 \begin_inset LatexCommand \index{cpp|see{sdcpp}}
4708 \begin_inset LatexCommand \url{http://gcc.gnu.org/}
4713 The C preprocessor is used to pull in #include sources, process #ifdef
4714 statements, #defines and so on.
4725 - The Assemblers and Linkage Editors
4728 This is retargettable assembler & linkage editor, it was developed by Alan
4730 John Hartman created the version for 8051, and I (Sandeep) have made some
4731 enhancements and bug fixes for it to work properly with SDCC.
4738 \begin_inset LatexCommand \index{s51}
4742 is a freeware, opensource simulator developed by Daniel Drotos.
4743 The simulator is built as part of the build process.
4744 For more information visit Daniel's web site at:
4745 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
4750 It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
4754 sdcdb - Source Level Debugger
4758 \begin_inset LatexCommand \index{SDCDB (debugger)}
4762 is the companion source level debugger.
4763 More about SDCDB in section
4764 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
4769 The current version of the debugger uses Daniel's Simulator S51
4770 \begin_inset LatexCommand \index{s51}
4774 , but can be easily changed to use other simulators.
4783 Single Source File Projects
4786 For single source file 8051 projects the process is very simple.
4787 Compile your programs with the following command
4790 "sdcc sourcefile.c".
4794 This will compile, assemble and link your source file.
4795 Output files are as follows:
4799 \begin_inset LatexCommand \index{<file>.asm}
4804 \begin_inset LatexCommand \index{Assembler source}
4808 file created by the compiler
4812 \begin_inset LatexCommand \index{<file>.lst}
4817 \begin_inset LatexCommand \index{Assembler listing}
4821 file created by the Assembler
4825 \begin_inset LatexCommand \index{<file>.rst}
4830 \begin_inset LatexCommand \index{Assembler listing}
4834 file updated with linkedit information, created by linkage editor
4838 \begin_inset LatexCommand \index{<file>.sym}
4843 \begin_inset LatexCommand \index{Symbol listing}
4847 for the sourcefile, created by the assembler
4851 \begin_inset LatexCommand \index{<file>.rel}
4856 \begin_inset LatexCommand \index{<file>.o}
4861 \begin_inset LatexCommand \index{Object file}
4865 created by the assembler, input to Linkage editor
4869 \begin_inset LatexCommand \index{<file>.map}
4874 \begin_inset LatexCommand \index{Memory map}
4878 for the load module, created by the Linker
4882 \begin_inset LatexCommand \index{<file>.mem}
4886 - A file with a summary of the memory usage
4890 \begin_inset LatexCommand \index{<file>.ihx}
4894 - The load module in Intel hex format
4895 \begin_inset LatexCommand \index{Intel hex format}
4899 (you can select the Motorola S19 format
4900 \begin_inset LatexCommand \index{Motorola S19 format}
4915 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
4920 If you need another format you might want to use
4927 \begin_inset LatexCommand \index{objdump (tool)}
4938 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
4943 Both formats are documented in the documentation of srecord
4944 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
4952 \begin_inset LatexCommand \index{<file>.adb}
4956 - An intermediate file containing debug information needed to create the
4968 \begin_inset LatexCommand \index{-\/-debug}
4976 \begin_inset LatexCommand \index{<file>.cdb}
4980 - An optional file (with -
4990 -debug) containing debug information.
4991 The format is documented in cdbfileformat.pdf
4996 \begin_inset LatexCommand \index{<file> (no extension)}
5000 An optional AOMF or AOMF51
5001 \begin_inset LatexCommand \index{AOMF, AOMF51}
5006 \begin_inset LatexCommand \label{OMF file}
5010 file containing debug information (generated with option -
5037 ormat is commonly used by third party tools (debuggers
5038 \begin_inset LatexCommand \index{Debugger}
5042 , simulators, emulators)
5046 \begin_inset LatexCommand \index{<file>.dump*}
5050 - Dump file to debug the compiler it self (generated with option -
5060 -dumpall) (see section
5061 \begin_inset LatexCommand \ref{sub:Intermediate-Dump-Options}
5067 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
5073 \begin_inset Quotes sld
5076 Anatomy of the compiler
5077 \begin_inset Quotes srd
5083 Postprocessing the Intel Hex
5084 \begin_inset LatexCommand \index{Intel hex format}
5091 In most cases this won't be needed but the Intel Hex file
5092 \begin_inset LatexCommand \index{<file>.ihx}
5096 which is generated by SDCC might include lines of varying length and the
5097 addresses within the file are not guaranteed to be strictly ascending.
5098 If your toolchain or a bootloader does not like this you can use the tool
5104 \begin_inset LatexCommand \index{packihx (tool)}
5108 which is part of the SDCC distribution:
5115 packihx sourcefile.ihx >sourcefile.hex
5122 The separately available
5127 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
5131 package additionally allows to set undefined locations to a predefined
5132 value, to insert checksums
5133 \begin_inset LatexCommand \index{checksum}
5137 of various flavours (crc, add, xor) and to perform other manipulations
5138 (convert, split, crop, offset, ...).
5146 srec_cat\SpecialChar ~
5148 sourcefile.ihx -intel\SpecialChar ~
5150 -o sourcefile.hex -intel
5157 An example for a more complex command line
5163 the command backfills
5164 \begin_inset LatexCommand \index{backfill unused memory}
5168 unused memory with 0x12 and the overall 16 bit sum of the complete 64 kByte
5170 If the program counter on an mcs51 runs wild the backfill pattern 0x12
5171 will be interpreted as an
5179 (where an emergency routine could sit).
5190 srec_cat\SpecialChar ~
5191 sourcefile.ihx -intel\SpecialChar ~
5193 -fill 0x12 0x0000 0xfffe\SpecialChar ~
5194 -little-endian-checksum-nega
5195 tive 0xfffe 0x02 0x02\SpecialChar ~
5197 -o sourcefile.hex -intel
5206 The srecord package is available at
5207 \begin_inset LatexCommand \url{http://sf.net/projects/srecord}
5214 Projects with Multiple Source Files
5217 SDCC can compile only ONE file at a time.
5218 Let us for example assume that you have a project containing the following
5223 foo1.c (contains some functions)
5225 foo2.c (contains some more functions)
5227 foomain.c (contains more functions and the function main)
5235 The first two files will need to be compiled separately with the commands:
5267 Then compile the source file containing the
5272 \begin_inset LatexCommand \index{Linker}
5276 the files together with the following command:
5284 foomain.c\SpecialChar ~
5285 foo1.rel\SpecialChar ~
5290 \begin_inset LatexCommand \index{<file>.rel}
5302 can be separately compiled as well:
5313 sdcc foomain.rel foo1.rel foo2.rel
5320 The file containing the
5335 file specified in the command line, since the linkage editor processes
5336 file in the order they are presented to it.
5337 The linker is invoked from SDCC using a script file with extension .lnk
5338 \begin_inset LatexCommand \index{<file>.lnk}
5343 You can view this file to troubleshoot linking problems such as those arising
5344 from missing libraries.
5347 Projects with Additional Libraries
5348 \begin_inset LatexCommand \index{Libraries}
5355 Some reusable routines may be compiled into a library, see the documentation
5356 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
5360 \begin_inset LatexCommand \index{<file>.lib}
5367 Libraries created in this manner can be included in the command line.
5368 Make sure you include the -L <library-path> option to tell the linker where
5369 to look for these files if they are not in the current directory.
5370 Here is an example, assuming you have the source file
5382 (if that is not the same as your current project):
5389 sdcc foomain.c foolib.lib -L mylib
5400 must be an absolute path name.
5404 The most efficient way to use libraries is to keep separate modules in separate
5406 The lib file now should name all the modules.rel
5407 \begin_inset LatexCommand \index{<file>.rel}
5412 For an example see the standard library file
5416 in the directory <installdir>/share/lib/small.
5419 Using sdcclib to Create and Manage Libraries
5420 \begin_inset LatexCommand \index{sdcclib}
5427 Alternatively, instead of having a .rel file for each entry on the library
5428 file as described in the preceding section, sdcclib can be used to embed
5429 all the modules belonging to such library in the library file itself.
5430 This results in a larger library file, but it greatly reduces the number
5431 of disk files accessed by the linker.
5432 Additionally, the packed library file contains an index of all include
5433 modules and symbols that significantly speeds up the linking process.
5434 To display a list of options supported by sdcclib type:
5443 \begin_inset LatexCommand \index{sdcclib}
5454 To create a new library file, start by compiling all the required modules.
5492 This will create files _divsint.rel, _divuint.rel, _modsint.rel, _moduint.rel,
5494 The next step is to add the .rel files to the library file:
5502 sdcclib libint.lib _divsint.rel
5505 \begin_inset LatexCommand \index{sdcclib}
5515 sdcclib libint.lib _divuint.rel
5521 sdcclib libint.lib _modsint.rel
5527 sdcclib libint.lib _moduint.rel
5533 sdcclib libint.lib _mulint.rel
5540 If the file already exists in the library, it will be replaced.
5541 To see what modules and symbols are included in the library, options -s
5542 and -m are available.
5550 sdcclib -s libint.lib
5553 \begin_inset LatexCommand \index{sdcclib}
5662 \added_space_bottom bigskip
5663 If the source files are compiled using -
5674 \begin_inset LatexCommand \index{-\/-debug}
5678 , the corresponding debug information file .adb will be include in the library
5680 The library files created with sdcclib are plain text files, so they can
5681 be viewed with a text editor.
5682 It is not recomended to modify a library file created with sdcclib using
5683 a text editor, as there are file indexes numbers located accross the file
5684 used by the linker to quickly locate the required module to link.
5685 Once a .rel file (as well as a .adb file) is added to a library using sdcclib,
5686 it can be safely deleted, since all the information required for linking
5687 is embedded in the library file itself.
5688 Library files created using sdcclib are used as described in the preceding
5692 Command Line Options
5693 \begin_inset LatexCommand \index{Command Line Options}
5700 Processor Selection Options
5701 \begin_inset LatexCommand \index{Options processor selection}
5706 \begin_inset LatexCommand \index{Processor selection options}
5712 \labelwidthstring 00.00.0000
5717 \begin_inset LatexCommand \index{-mmcs51}
5723 Generate code for the Intel MCS51
5724 \begin_inset LatexCommand \index{MCS51}
5728 family of processors.
5729 This is the default processor target.
5731 \labelwidthstring 00.00.0000
5736 \begin_inset LatexCommand \index{-mds390}
5742 Generate code for the Dallas DS80C390
5743 \begin_inset LatexCommand \index{DS80C390}
5749 \labelwidthstring 00.00.0000
5754 \begin_inset LatexCommand \index{-mds400}
5760 Generate code for the Dallas DS80C400
5761 \begin_inset LatexCommand \index{DS80C400}
5767 \labelwidthstring 00.00.0000
5772 \begin_inset LatexCommand \index{-mhc08}
5778 Generate code for the Freescale/Motorola HC08
5779 \begin_inset LatexCommand \index{HC08}
5783 family of processors.
5785 \labelwidthstring 00.00.0000
5790 \begin_inset LatexCommand \index{-mz80}
5796 Generate code for the Zilog Z80
5797 \begin_inset LatexCommand \index{Z80}
5801 family of processors.
5803 \labelwidthstring 00.00.0000
5808 \begin_inset LatexCommand \index{-mgbz80}
5814 Generate code for the GameBoy Z80
5815 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
5819 processor (Not actively maintained).
5821 \labelwidthstring 00.00.0000
5826 \begin_inset LatexCommand \index{-mavr}
5832 Generate code for the Atmel AVR
5833 \begin_inset LatexCommand \index{AVR}
5837 processor (Not maintained, not complete).
5838 AVR users should probably have a look at winavr
5839 \begin_inset LatexCommand \url{http://sourceforge.net/projects/winavr}
5844 \begin_inset LatexCommand \url{http://www.avrfreaks.net/index.php?name=PNphpBB2&file=index}
5851 I think it is fair to direct users there for now.
5852 Open source is also about avoiding unnecessary work .
5853 But I didn't find the 'official' link.
5855 \labelwidthstring 00.00.0000
5860 \begin_inset LatexCommand \index{-mpic14}
5866 Generate code for the Microchip PIC 14
5867 \begin_inset LatexCommand \index{PIC14}
5871 -bit processors (p16f84 and variants.
5872 In development, not complete).
5875 p16f627 p16f628 p16f84 p16f873 p16f877?
5877 \labelwidthstring 00.00.0000
5882 \begin_inset LatexCommand \index{-mpic16}
5888 Generate code for the Microchip PIC 16
5889 \begin_inset LatexCommand \index{PIC16}
5893 -bit processors (p18f452 and variants.
5894 In development, not complete).
5896 \labelwidthstring 00.00.0000
5902 Generate code for the Toshiba TLCS-900H
5903 \begin_inset LatexCommand \index{TLCS-900H}
5907 processor (Not maintained, not complete).
5909 \added_space_bottom bigskip \labelwidthstring 00.00.0000
5914 \begin_inset LatexCommand \index{-mxa51}
5920 Generate code for the Phillips XA51
5921 \begin_inset LatexCommand \index{XA51}
5925 processor (Not maintained, not complete).
5928 Preprocessor Options
5929 \begin_inset LatexCommand \index{Options preprocessor}
5934 \begin_inset LatexCommand \index{Preprocessor options}
5939 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
5945 \labelwidthstring 00.00.0000
5950 \begin_inset LatexCommand \index{-I<path>}
5956 The additional location where the pre processor will look for <..h> or
5957 \begin_inset Quotes eld
5961 \begin_inset Quotes erd
5966 \labelwidthstring 00.00.0000
5971 \begin_inset LatexCommand \index{-D<macro[=value]>}
5977 Command line definition of macros.
5978 Passed to the preprocessor.
5980 \labelwidthstring 00.00.0000
5985 \begin_inset LatexCommand \index{-M}
5991 Tell the preprocessor to output a rule suitable for make describing the
5992 dependencies of each object file.
5993 For each source file, the preprocessor outputs one make-rule whose target
5994 is the object file name for that source file and whose dependencies are
5995 all the files `#include'd in it.
5996 This rule may be a single line or may be continued with `
5998 '-newline if it is long.
5999 The list of rules is printed on standard output instead of the preprocessed
6002 \begin_inset LatexCommand \index{-E}
6008 \labelwidthstring 00.00.0000
6013 \begin_inset LatexCommand \index{-C}
6019 Tell the preprocessor not to discard comments.
6020 Used with the `-E' option.
6022 \labelwidthstring 00.00.0000
6027 \begin_inset LatexCommand \index{-MM}
6038 Like `-M' but the output mentions only the user header files included with
6040 \begin_inset Quotes eld
6044 System header files included with `#include <file>' are omitted.
6046 \labelwidthstring 00.00.0000
6051 \begin_inset LatexCommand \index{-Aquestion(answer)}
6057 Assert the answer answer for question, in case it is tested with a preprocessor
6058 conditional such as `#if #question(answer)'.
6059 `-A-' disables the standard assertions that normally describe the target
6062 \labelwidthstring 00.00.0000
6067 \begin_inset LatexCommand \index{-Umacro}
6073 Undefine macro macro.
6074 `-U' options are evaluated after all `-D' options, but before any `-include'
6075 and `-imacros' options.
6077 \labelwidthstring 00.00.0000
6082 \begin_inset LatexCommand \index{-dM}
6088 Tell the preprocessor to output only a list of the macro definitions that
6089 are in effect at the end of preprocessing.
6090 Used with the `-E' option.
6092 \labelwidthstring 00.00.0000
6097 \begin_inset LatexCommand \index{-dD}
6103 Tell the preprocessor to pass all macro definitions into the output, in
6104 their proper sequence in the rest of the output.
6106 \labelwidthstring 00.00.0000
6111 \begin_inset LatexCommand \index{-dN}
6122 Like `-dD' except that the macro arguments and contents are omitted.
6123 Only `#define name' is included in the output.
6125 \added_space_bottom bigskip \labelwidthstring 00.00.0000
6130 preprocessorOption[,preprocessorOption]
6133 \begin_inset LatexCommand \index{-Wp preprocessorOption[,preprocessorOption]}
6138 Pass the preprocessorOption to the preprocessor
6143 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
6148 SDCC uses an adapted version of the preprocessor
6152 of the GNU Compiler Collection
6153 \begin_inset LatexCommand \index{gcc (GNU Compiler Collection)}
6162 \begin_inset LatexCommand \url{http://gcc.gnu.org/}
6166 ), if you need more dedicated options please refer to the GCC\SpecialChar ~
6171 \begin_inset LatexCommand \htmlurl{http://www.gnu.org/software/gcc/onlinedocs/}
6179 \begin_inset LatexCommand \index{Options linker}
6184 \begin_inset LatexCommand \index{Linker options}
6190 \labelwidthstring 00.00.0000
6210 \begin_inset LatexCommand \index{-\/-lib-path <path>}
6215 \begin_inset LatexCommand \index{-L -\/-lib-path}
6222 <absolute path to additional libraries> This option is passed to the linkage
6223 editor's additional libraries
6224 \begin_inset LatexCommand \index{Libraries}
6229 The path name must be absolute.
6230 Additional library files may be specified in the command line.
6231 See section Compiling programs for more details.
6233 \labelwidthstring 00.00.0000
6250 \begin_inset LatexCommand \index{-\/-xram-loc <Value>}
6255 <Value> The start location of the external ram
6256 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
6260 , default value is 0.
6261 The value entered can be in Hexadecimal or Decimal format, e.g.: -
6271 -xram-loc 0x8000 or -
6283 \labelwidthstring 00.00.0000
6300 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
6305 <Value> The start location of the code
6306 \begin_inset LatexCommand \index{code}
6310 segment, default value 0.
6311 Note when this option is used the interrupt vector table
6312 \begin_inset LatexCommand \index{interrupt vector table}
6316 is also relocated to the given address.
6317 The value entered can be in Hexadecimal or Decimal format, e.g.: -
6327 -code-loc 0x8000 or -
6339 \labelwidthstring 00.00.0000
6356 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
6361 <Value> By default the stack
6362 \begin_inset LatexCommand \index{stack}
6366 is placed after the data segment.
6367 Using this option the stack can be placed anywhere in the internal memory
6369 The value entered can be in Hexadecimal or Decimal format, e.g.
6380 -stack-loc 0x20 or -
6391 Since the sp register is incremented before a push or call, the initial
6392 sp will be set to one byte prior the provided value.
6393 The provided value should not overlap any other memory areas such as used
6394 register banks or the data segment and with enough space for the current
6412 \begin_inset LatexCommand \index{-\/-pack-iram}
6416 option (which is now a default setting) will override this setting, so
6417 you should also specify the
6433 \begin_inset LatexCommand \index{-\/-no-pack-iram}
6437 option if you need to manually place the stack.
6439 \labelwidthstring 00.00.0000
6456 \begin_inset LatexCommand \index{-\/-xstack-loc <Value>}
6461 <Value> By default the external stack
6462 \begin_inset LatexCommand \index{xstack}
6466 is placed after the pdata
6467 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
6472 Using this option the xstack can be placed anywhere in the external memory
6474 The value entered can be in Hexadecimal or Decimal format, e.g.
6485 -xstack-loc 0x8000 or -
6496 The provided value should not overlap any other memory areas such as the
6497 pdata or xdata segment and with enough space for the current application.
6499 \labelwidthstring 00.00.0000
6516 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
6521 <Value> The start location of the internal ram data
6522 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
6527 The value entered can be in Hexadecimal or Decimal format, eg.
6549 (By default, the start location of the internal ram data segment is set
6550 as low as possible in memory, taking into account the used register banks
6551 and the bit segment at address 0x20.
6552 For example if register banks 0 and 1 are used without bit variables, the
6553 data segment will be set, if -
6563 -data-loc is not used, to location 0x10.)
6565 \labelwidthstring 00.00.0000
6582 \begin_inset LatexCommand \index{-\/-idata-loc <Value>}
6587 <Value> The start location of the indirectly addressable internal ram
6588 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
6592 of the 8051, default value is 0x80.
6593 The value entered can be in Hexadecimal or Decimal format, eg.
6604 -idata-loc 0x88 or -
6616 \labelwidthstring 00.00.0000
6633 <Value> The start location of the bit
6634 \begin_inset LatexCommand \index{bit}
6638 addressable internal ram of the 8051.
6644 Instead an option can be passed directly to the linker: -Wl\SpecialChar ~
6647 \labelwidthstring 00.00.0000
6662 \begin_inset LatexCommand \index{-\/-out-fmt-ihx}
6671 The linker output (final object code) is in Intel Hex format.
6672 \begin_inset LatexCommand \index{Intel hex format}
6676 This is the default option.
6677 The format itself is documented in the documentation of srecord
6678 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
6684 \labelwidthstring 00.00.0000
6699 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
6708 The linker output (final object code) is in Motorola S19 format
6709 \begin_inset LatexCommand \index{Motorola S19 format}
6714 The format itself is documented in the documentation of srecord.
6716 \labelwidthstring 00.00.0000
6731 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
6736 \begin_inset LatexCommand \index{HC08!Options!-\/-out-fmt-elf}
6745 The linker output (final object code) is in ELF format
6746 \begin_inset LatexCommand \index{ELF format}
6751 (Currently only supported for the HC08
6752 \begin_inset LatexCommand \index{HC08}
6758 \added_space_bottom bigskip \labelwidthstring 00.00.0000
6763 linkOption[,linkOption]
6766 \begin_inset LatexCommand \index{-Wl linkOption[,linkOption]}
6771 Pass the linkOption to the linker.
6772 If a bootloader is used an option like
6773 \begin_inset Quotes sld
6778 \begin_inset Quotes srd
6781 would be typical to set the start of the code segment.
6782 See also #pragma constseg and #pragma codeseg in section
6783 \begin_inset LatexCommand \ref{sec:Pragmas}
6788 File sdcc/as/doc/asxhtm.html has more on linker options.
6792 \begin_inset LatexCommand \index{Options MCS51}
6797 \begin_inset LatexCommand \index{MCS51 options}
6803 \labelwidthstring 00.00.0000
6818 \begin_inset LatexCommand \index{-\/-model-small}
6829 Generate code for Small Model programs, see section Memory Models for more
6831 This is the default model.
6833 \labelwidthstring 00.00.0000
6848 \begin_inset LatexCommand \index{-\/-model-medium}
6854 Generate code for Medium model programs, see section Memory Models for
6856 If this option is used all source files in the project have to be compiled
6858 It must also be used when invoking the linker.
6860 \labelwidthstring 00.00.0000
6875 \begin_inset LatexCommand \index{-\/-model-large}
6881 Generate code for Large model programs, see section Memory Models for more
6883 If this option is used all source files in the project have to be compiled
6885 It must also be used when invoking the linker.
6887 \labelwidthstring 00.00.0000
6902 \begin_inset LatexCommand \index{-\/-xstack}
6908 Uses a pseudo stack in the pdata
6909 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
6913 area (usually the first 256 bytes in the external ram) for allocating variables
6914 and passing parameters.
6916 \begin_inset LatexCommand \ref{sub:External-Stack}
6921 External Stack for more details.
6923 \labelwidthstring 00.00.0000
6941 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
6945 Causes the linker to check if the internal ram usage is within limits of
6948 \labelwidthstring 00.00.0000
6966 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
6970 Causes the linker to check if the external ram usage is within limits of
6973 \labelwidthstring 00.00.0000
6991 \begin_inset LatexCommand \index{-\/-code-size <Value>}
6995 Causes the linker to check if the code memory usage is within limits of
6998 \labelwidthstring 00.00.0000
7016 \begin_inset LatexCommand \index{-\/-stack-size <Value>}
7020 Causes the linker to check if there is at minimum <Value> bytes for stack.
7022 \labelwidthstring 00.00.0000
7040 \begin_inset LatexCommand \index{-\/-pack-iram}
7044 Causes the linker to use unused register banks for data variables and pack
7045 data, idata and stack together.
7046 This is the default now.
7048 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7066 \begin_inset LatexCommand \index{-\/-no-pack-iram}
7070 Causes the linker to use old style for allocating memory areas.
7073 DS390 / DS400 Options
7074 \begin_inset LatexCommand \index{Options DS390}
7079 \begin_inset LatexCommand \index{DS390}
7085 \labelwidthstring 00.00.0000
7102 \begin_inset LatexCommand \index{DS390!Options!-\/-model-flat24}
7112 Generate 24-bit flat mode code.
7113 This is the one and only that the ds390 code generator supports right now
7114 and is default when using
7119 See section Memory Models for more details.
7121 \labelwidthstring 00.00.0000
7136 \begin_inset LatexCommand \index{DS390!Options!-\/-protect-sp-update}
7142 disable interrupts during ESP:SP updates.
7144 \labelwidthstring 00.00.0000
7161 \begin_inset LatexCommand \index{DS390!Options!-\/-stack-10bit}
7165 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
7166 This is the one and only that the ds390 code generator supports right now
7167 and is default when using
7172 In this mode, the stack is located in the lower 1K of the internal RAM,
7173 which is mapped to 0x400000.
7174 Note that the support is incomplete, since it still uses a single byte
7175 as the stack pointer.
7176 This means that only the lower 256 bytes of the potential 1K stack space
7177 will actually be used.
7178 However, this does allow you to reclaim the precious 256 bytes of low RAM
7179 for use for the DATA and IDATA segments.
7180 The compiler will not generate any code to put the processor into 10 bit
7182 It is important to ensure that the processor is in this mode before calling
7183 any re-entrant functions compiled with this option.
7184 In principle, this should work with the
7197 \begin_inset LatexCommand \index{-\/-stack-auto}
7203 option, but that has not been tested.
7204 It is incompatible with the
7217 \begin_inset LatexCommand \index{-\/-xstack}
7224 It also only makes sense if the processor is in 24 bit contiguous addressing
7237 -model-flat24 option
7241 \labelwidthstring 00.00.0000
7256 \begin_inset LatexCommand \index{DS390!Options!-\/-stack-probe}
7262 insert call to function __stack_probe at each function prologue.
7264 \labelwidthstring 00.00.0000
7279 \begin_inset LatexCommand \index{DS390!Options!-\/-tini-libid}
7285 <nnnn> LibraryID used in -mTININative.
7288 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7303 \begin_inset LatexCommand \index{DS390!Options!-\/-use-accelerator}
7309 generate code for DS390 Arithmetic Accelerator.
7314 \begin_inset LatexCommand \index{Options Z80}
7319 \begin_inset LatexCommand \index{Z80}
7325 \labelwidthstring 00.00.0000
7342 \begin_inset LatexCommand \index{Z80!Options!-\/-callee-saves-bc}
7352 Force a called function to always save BC.
7354 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7371 \begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}
7375 When linking, skip the standard crt0.o object file.
7376 You must provide your own crt0.o for your system when linking.
7380 Optimization Options
7381 \begin_inset LatexCommand \index{Options optimization}
7386 \begin_inset LatexCommand \index{Optimization options}
7392 \labelwidthstring 00.00.0000
7407 \begin_inset LatexCommand \index{-\/-nogcse}
7413 Will not do global subexpression elimination, this option may be used when
7414 the compiler creates undesirably large stack/data spaces to store compiler
7424 \begin_inset LatexCommand \index{sloc (spill location)}
7429 A warning message will be generated when this happens and the compiler
7430 will indicate the number of extra bytes it allocated.
7431 It is recommended that this option NOT be used, #pragma\SpecialChar ~
7433 \begin_inset LatexCommand \index{\#pragma nogcse}
7437 can be used to turn off global subexpression elimination
7438 \begin_inset LatexCommand \index{Subexpression elimination}
7442 for a given function only.
7444 \labelwidthstring 00.00.0000
7459 \begin_inset LatexCommand \index{-\/-noinvariant}
7465 Will not do loop invariant optimizations, this may be turned off for reasons
7466 explained for the previous option.
7467 For more details of loop optimizations performed see Loop Invariants in
7469 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
7474 It is recommended that this option NOT be used, #pragma\SpecialChar ~
7476 \begin_inset LatexCommand \index{\#pragma noinvariant}
7480 can be used to turn off invariant optimizations for a given function only.
7482 \labelwidthstring 00.00.0000
7497 \begin_inset LatexCommand \index{-\/-noinduction}
7503 Will not do loop induction optimizations, see section strength reduction
7505 It is recommended that this option is NOT used, #pragma\SpecialChar ~
7507 \begin_inset LatexCommand \index{\#pragma noinduction}
7511 can be used to turn off induction optimizations for a given function only.
7513 \labelwidthstring 00.00.0000
7528 \begin_inset LatexCommand \index{-\/-nojtbound}
7539 Will not generate boundary condition check when switch statements
7540 \begin_inset LatexCommand \index{switch statement}
7544 are implemented using jump-tables.
7546 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
7551 Switch Statements for more details.
7552 It is recommended that this option is NOT used, #pragma\SpecialChar ~
7554 \begin_inset LatexCommand \index{\#pragma nojtbound}
7558 can be used to turn off boundary checking for jump tables for a given function
7561 \labelwidthstring 00.00.0000
7576 \begin_inset LatexCommand \index{-\/-noloopreverse}
7585 Will not do loop reversal
7586 \begin_inset LatexCommand \index{Loop reversing}
7592 \labelwidthstring 00.00.0000
7609 \begin_inset LatexCommand \index{-\/-nolabelopt }
7613 Will not optimize labels (makes the dumpfiles more readable).
7615 \labelwidthstring 00.00.0000
7630 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
7636 Will not memcpy initialized data from code space into xdata space.
7637 This saves a few bytes in code space if you don't have initialized data
7638 \begin_inset LatexCommand \index{Variable initialization}
7644 \labelwidthstring 00.00.0000
7659 \begin_inset LatexCommand \index{-\/-nooverlay}
7665 The compiler will not overlay parameters and local variables of any function,
7666 see section Parameters and local variables for more details.
7668 \labelwidthstring 00.00.0000
7683 \begin_inset LatexCommand \index{-\/-no-peep}
7689 Disable peep-hole optimization with built-in rules.
7691 \labelwidthstring 00.00.0000
7708 \begin_inset LatexCommand \index{-\/-peep-file}
7713 <filename> This option can be used to use additional rules to be used by
7714 the peep hole optimizer.
7716 \begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
7721 Peep Hole optimizations for details on how to write these rules.
7723 \labelwidthstring 00.00.0000
7738 \begin_inset LatexCommand \index{-\/-peep-asm}
7744 Pass the inline assembler code through the peep hole optimizer.
7745 This can cause unexpected changes to inline assembler code, please go through
7746 the peephole optimizer
7747 \begin_inset LatexCommand \index{Peephole optimizer}
7751 rules defined in the source file tree '<target>/peeph.def' before using
7754 \labelwidthstring 00.00.0000
7769 \begin_inset LatexCommand \index{-\/-opt-code-speed}
7775 The compiler will optimize code generation towards fast code, possibly
7776 at the expense of code size.
7778 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7793 \begin_inset LatexCommand \index{-\/-opt-code-size}
7799 The compiler will optimize code generation towards compact code, possibly
7800 at the expense of code speed.
7804 \begin_inset LatexCommand \index{Options other}
7810 \labelwidthstring 00.00.0000
7826 \begin_inset LatexCommand \index{-\/-compile-only}
7831 \begin_inset LatexCommand \index{-c -\/-compile-only}
7837 will compile and assemble the source, but will not call the linkage editor.
7839 \labelwidthstring 00.00.0000
7858 \begin_inset LatexCommand \index{-\/-c1mode}
7864 reads the preprocessed source from standard input and compiles it.
7865 The file name for the assembler output must be specified using the -o option.
7867 \labelwidthstring 00.00.0000
7872 \begin_inset LatexCommand \index{-E}
7878 Run only the C preprocessor.
7879 Preprocess all the C source files specified and output the results to standard
7882 \labelwidthstring 00.00.0000
7888 \begin_inset LatexCommand \index{-o <path/file>}
7894 The output path resp.
7895 file where everything will be placed.
7896 If the parameter is a path, it must have a trailing slash (or backslash
7897 for the Windows binaries) to be recognized as a path.
7900 \labelwidthstring 00.00.0000
7915 \begin_inset LatexCommand \index{-\/-stack-auto}
7926 All functions in the source file will be compiled as
7931 \begin_inset LatexCommand \index{reentrant}
7936 the parameters and local variables will be allocated on the stack
7937 \begin_inset LatexCommand \index{stack}
7943 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
7947 Parameters and Local Variables for more details.
7948 If this option is used all source files in the project should be compiled
7950 It automatically implies --int-long-reent and --float-reent.
7953 \labelwidthstring 00.00.0000
7968 \begin_inset LatexCommand \index{-\/-callee-saves}
7972 function1[,function2][,function3]....
7975 The compiler by default uses a caller saves convention for register saving
7976 across function calls, however this can cause unnecessary register pushing
7977 & popping when calling small functions from larger functions.
7978 This option can be used to switch the register saving convention for the
7979 function names specified.
7980 The compiler will not save registers when calling these functions, no extra
7981 code will be generated at the entry & exit (function prologue
7984 \begin_inset LatexCommand \index{function prologue}
7993 \begin_inset LatexCommand \index{function epilogue}
7999 ) for these functions to save & restore the registers used by these functions,
8000 this can SUBSTANTIALLY reduce code & improve run time performance of the
8002 In the future the compiler (with inter procedural analysis) will be able
8003 to determine the appropriate scheme to use for each function call.
8004 DO NOT use this option for built-in functions such as _mulint..., if this
8005 option is used for a library function the appropriate library function
8006 needs to be recompiled with the same option.
8007 If the project consists of multiple source files then all the source file
8008 should be compiled with the same -
8018 -callee-saves option string.
8019 Also see #pragma\SpecialChar ~
8021 \begin_inset LatexCommand \index{\#pragma callee\_saves}
8027 \labelwidthstring 00.00.0000
8042 \begin_inset LatexCommand \index{-\/-debug}
8051 When this option is used the compiler will generate debug information.
8052 The debug information collected in a file with .cdb extension can be used
8054 For more information see documentation for SDCDB.
8055 Another file with no extension contains debug information in AOMF or AOMF51
8056 \begin_inset LatexCommand \index{AOMF, AOMF51}
8060 format which is commonly used by third party tools.
8062 \labelwidthstring 00.00.0000
8067 \begin_inset LatexCommand \index{-S}
8078 Stop after the stage of compilation proper; do not assemble.
8079 The output is an assembler code file for the input file specified.
8081 \labelwidthstring 00.00.0000
8096 \begin_inset LatexCommand \index{-\/-int-long-reent}
8102 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
8103 Note by default these libraries are compiled as non-reentrant.
8104 See section Installation for more details.
8106 \labelwidthstring 00.00.0000
8121 \begin_inset LatexCommand \index{-\/-cyclomatic}
8130 This option will cause the compiler to generate an information message for
8131 each function in the source file.
8132 The message contains some
8136 information about the function.
8137 The number of edges and nodes the compiler detected in the control flow
8138 graph of the function, and most importantly the
8140 cyclomatic complexity
8141 \begin_inset LatexCommand \index{Cyclomatic complexity}
8147 see section on Cyclomatic Complexity for more details.
8149 \labelwidthstring 00.00.0000
8164 \begin_inset LatexCommand \index{-\/-float-reent}
8170 Floating point library is compiled as reentrant
8171 \begin_inset LatexCommand \index{reentrant}
8176 See section Installation for more details.
8178 \labelwidthstring 00.00.0000
8193 \begin_inset LatexCommand \index{-\/-main-return}
8199 This option can be used if the code generated is called by a monitor program
8200 or if the main routine includes an endless loop.
8201 This option results in slightly smaller code and saves two bytes of stack
8203 The return from the 'main'
8204 \begin_inset LatexCommand \index{main return}
8208 function will return to the function calling main.
8209 The default setting is to lock up i.e.
8216 \labelwidthstring 00.00.0000
8231 \begin_inset LatexCommand \index{-\/-nostdinc}
8237 This will prevent the compiler from passing on the default include path
8238 to the preprocessor.
8240 \labelwidthstring 00.00.0000
8255 \begin_inset LatexCommand \index{-\/-nostdlib}
8261 This will prevent the compiler from passing on the default library
8262 \begin_inset LatexCommand \index{Libraries}
8268 \labelwidthstring 00.00.0000
8283 \begin_inset LatexCommand \index{-\/-verbose}
8289 Shows the various actions the compiler is performing.
8291 \labelwidthstring 00.00.0000
8296 \begin_inset LatexCommand \index{-V}
8302 Shows the actual commands the compiler is executing.
8304 \labelwidthstring 00.00.0000
8319 \begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
8325 Hides your ugly and inefficient c-code from the asm file, so you can always
8326 blame the compiler :)
8328 \labelwidthstring 00.00.0000
8343 \begin_inset LatexCommand \index{-\/-no-peep-comments}
8349 Will not include peep-hole comments in the generated files.
8351 \labelwidthstring 00.00.0000
8366 \begin_inset LatexCommand \index{-\/-i-code-in-asm}
8372 Include i-codes in the asm file.
8373 Sounds like noise but is most helpful for debugging the compiler itself.
8375 \labelwidthstring 00.00.0000
8390 \begin_inset LatexCommand \index{-\/-less-pedantic}
8396 Disable some of the more pedantic warnings
8397 \begin_inset LatexCommand \index{Warnings}
8401 (jwk burps: please be more specific here, please!).
8403 \labelwidthstring 00.00.0000
8417 -disable-warning\SpecialChar ~
8419 \begin_inset LatexCommand \index{-\/-disable-warning}
8425 Disable specific warning with number <nnnn>.
8427 \labelwidthstring 00.00.0000
8442 \begin_inset LatexCommand \index{-\/-print-search-dirs}
8448 Display the directories in the compiler's search path
8450 \labelwidthstring 00.00.0000
8465 \begin_inset LatexCommand \index{-\/-vc}
8471 Display errors and warnings using MSVC style, so you can use SDCC with
8472 the visual studio IDE
8473 \begin_inset LatexCommand \index{IDE}
8478 With SDCC both offering a GCC-like (the default) and a MSVC-like
8479 \begin_inset LatexCommand \index{MSVC output style}
8483 output style, integration into most programming editors should be straightforwa
8486 \labelwidthstring 00.00.0000
8501 \begin_inset LatexCommand \index{-\/-use-stdout}
8507 Send errors and warnings to stdout instead of stderr.
8509 \labelwidthstring 00.00.0000
8514 asmOption[,asmOption]
8517 \begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
8522 Pass the asmOption to the assembler
8523 \begin_inset LatexCommand \index{Options assembler}
8528 \begin_inset LatexCommand \index{Assembler options}
8533 See file sdcc/as/doc/asxhtm.html for assembler options.cd
8535 \labelwidthstring 00.00.0000
8550 \begin_inset LatexCommand \index{-\/-std-sdcc89}
8556 Generally follow the C89 standard, but allow SDCC features that conflict
8557 with the standard (default).
8559 \labelwidthstring 00.00.0000
8574 \begin_inset LatexCommand \index{-\/-std-c89}
8580 Follow the C89 standard and disable SDCC features that conflict with the
8583 \labelwidthstring 00.00.0000
8598 \begin_inset LatexCommand \index{-\/-std-sdcc99}
8604 Generally follow the C99 standard, but allow SDCC features that conflict
8605 with the standard (incomplete support).
8607 \labelwidthstring 00.00.0000
8622 \begin_inset LatexCommand \index{-\/-std-sdcc99}
8628 Follow the C99 standard and disable SDCC features that conflict with the
8629 standard (incomplete support).
8631 \labelwidthstring 00.00.0000
8648 \begin_inset LatexCommand \index{-\/-codeseg <Value>}
8653 <Name> The name to be used for the code
8654 \begin_inset LatexCommand \index{code}
8658 segment, default CSEG.
8659 This is useful if you need to tell the compiler to put the code in a special
8660 segment so you can later on tell the linker to put this segment in a special
8662 Can be used for instance when using bank switching to put the code in a
8665 \labelwidthstring 00.00.0000
8682 \begin_inset LatexCommand \index{-\/-constseg <Value>}
8687 <Name> The name to be used for the const
8688 \begin_inset LatexCommand \index{code}
8692 segment, default CONST.
8693 This is useful if you need to tell the compiler to put the const data in
8694 a special segment so you can later on tell the linker to put this segment
8695 in a special place in memory.
8696 Can be used for instance when using bank switching to put the const data
8699 \added_space_bottom bigskip \labelwidthstring 00.00.0000
8711 a SDCC compiler option but if you want
8715 warnings you can use a separate tool dedicated to syntax checking like
8717 \begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
8722 \begin_inset LatexCommand \index{lint (syntax checking tool)}
8727 \begin_inset LatexCommand \url{http://www.splint.org}
8732 To make your source files parseable by splint you will have to include
8738 \begin_inset LatexCommand \index{splint (syntax checking tool)}
8742 in your source file and add brackets around extended keywords (like
8745 \begin_inset Quotes sld
8758 \begin_inset Quotes srd
8766 \begin_inset Quotes sld
8769 __interrupt\SpecialChar ~
8771 \begin_inset Quotes srd
8779 Splint has an excellent on line manual at
8780 \begin_inset LatexCommand \url{http://www.splint.org/manual/}
8784 and it's capabilities go beyond pure syntax checking.
8785 You'll need to tell splint the location of SDCC's include files so a typical
8786 command line could look like this:
8790 splint\SpecialChar ~
8792 /usr/local/share/sdcc/include/mcs51/\SpecialChar ~
8797 Intermediate Dump Options
8798 \begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
8803 \begin_inset LatexCommand \index{Options intermediate dump}
8808 \begin_inset LatexCommand \index{Intermediate dump options}
8815 The following options are provided for the purpose of retargetting and debugging
8817 They provide a means to dump the intermediate code (iCode
8818 \begin_inset LatexCommand \index{iCode}
8822 ) generated by the compiler in human readable form at various stages of
8823 the compilation process.
8824 More on iCodes see chapter
8825 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
8830 \begin_inset Quotes srd
8833 The anatomy of the compiler
8834 \begin_inset Quotes srd
8839 \labelwidthstring 00.00.0000
8854 \begin_inset LatexCommand \index{-\/-dumpraw}
8860 This option will cause the compiler to dump the intermediate code into
8863 <source filename>.dumpraw
8865 just after the intermediate code has been generated for a function, i.e.
8866 before any optimizations are done.
8868 \begin_inset LatexCommand \index{Basic blocks}
8872 at this stage ordered in the depth first number, so they may not be in
8873 sequence of execution.
8875 \labelwidthstring 00.00.0000
8890 \begin_inset LatexCommand \index{-\/-dumpgcse}
8896 Will create a dump of iCode's, after global subexpression elimination
8897 \begin_inset LatexCommand \index{Global subexpression elimination}
8903 <source filename>.dumpgcse.
8905 \labelwidthstring 00.00.0000
8920 \begin_inset LatexCommand \index{-\/-dumpdeadcode}
8926 Will create a dump of iCode's, after deadcode elimination
8927 \begin_inset LatexCommand \index{Dead-code elimination}
8933 <source filename>.dumpdeadcode.
8935 \labelwidthstring 00.00.0000
8950 \begin_inset LatexCommand \index{-\/-dumploop}
8959 Will create a dump of iCode's, after loop optimizations
8960 \begin_inset LatexCommand \index{Loop optimization}
8966 <source filename>.dumploop.
8968 \labelwidthstring 00.00.0000
8983 \begin_inset LatexCommand \index{-\/-dumprange}
8992 Will create a dump of iCode's, after live range analysis
8993 \begin_inset LatexCommand \index{Live range analysis}
8999 <source filename>.dumprange.
9001 \labelwidthstring 00.00.0000
9016 \begin_inset LatexCommand \index{-\/-dumlrange}
9022 Will dump the life ranges
9023 \begin_inset LatexCommand \index{Live range analysis}
9029 \labelwidthstring 00.00.0000
9044 \begin_inset LatexCommand \index{-\/-dumpregassign}
9053 Will create a dump of iCode's, after register assignment
9054 \begin_inset LatexCommand \index{Register assignment}
9060 <source filename>.dumprassgn.
9062 \labelwidthstring 00.00.0000
9077 \begin_inset LatexCommand \index{-\/-dumplrange}
9083 Will create a dump of the live ranges of iTemp's
9085 \added_space_bottom bigskip \labelwidthstring 00.00.0000
9100 \begin_inset LatexCommand \index{-\/-dumpall}
9111 Will cause all the above mentioned dumps to be created.
9114 Redirecting output on Windows Shells
9116 \added_space_bottom bigskip
9117 By default SDCC writes it's error messages to
9118 \begin_inset Quotes sld
9122 \begin_inset Quotes srd
9126 To force all messages to
9127 \begin_inset Quotes sld
9131 \begin_inset Quotes srd
9155 \begin_inset LatexCommand \index{-\/-use-stdout}
9160 Additionally, if you happen to have visual studio installed in your windows
9161 machine, you can use it to compile your sources using a custom build and
9177 \begin_inset LatexCommand \index{-\/-vc}
9182 Something like this should work:
9226 -model-large -c $(InputPath)
9229 Environment variables
9230 \begin_inset LatexCommand \index{Environment variables}
9237 SDCC recognizes the following environment variables:
9239 \labelwidthstring 00.00.0000
9244 \begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
9250 SDCC installs a signal handler
9251 \begin_inset LatexCommand \index{signal handler}
9255 to be able to delete temporary files after an user break (^C) or an exception.
9256 If this environment variable is set, SDCC won't install the signal handler
9257 in order to be able to debug SDCC.
9259 \labelwidthstring 00.00.0000
9266 \begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
9272 Path, where temporary files will be created.
9273 The order of the variables is the search order.
9274 In a standard *nix environment these variables are not set, and there's
9275 no need to set them.
9276 On Windows it's recommended to set one of them.
9278 \labelwidthstring 00.00.0000
9283 \begin_inset LatexCommand \index{SDCC\_HOME}
9290 \begin_inset LatexCommand \ref{sub:Install-paths}
9296 \begin_inset Quotes sld
9300 \begin_inset Quotes srd
9305 \labelwidthstring 00.00.0000
9310 \begin_inset LatexCommand \index{SDCC\_INCLUDE}
9317 \begin_inset LatexCommand \ref{sub:Search-Paths}
9323 \begin_inset Quotes sld
9327 \begin_inset Quotes srd
9332 \labelwidthstring 00.00.0000
9337 \begin_inset LatexCommand \index{SDCC\_LIB}
9344 \begin_inset LatexCommand \ref{sub:Search-Paths}
9350 \begin_inset Quotes sld
9354 \begin_inset Quotes srd
9359 \added_space_bottom bigskip
9360 There are some more environment variables recognized by SDCC, but these
9361 are solely used for debugging purposes.
9362 They can change or disappear very quickly, and will never be documented.
9365 Storage Class Language Extensions
9368 MCS51/DS390 Storage Class
9369 \begin_inset LatexCommand \index{Storage class}
9376 In addition to the ANSI storage classes SDCC allows the following MCS51
9377 specific storage classes:
9378 \layout Subsubsection
9381 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
9386 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
9391 \begin_inset LatexCommand \index{near (storage class)}
9396 \begin_inset LatexCommand \index{\_\_near (storage class)}
9407 storage class for the Small Memory model (
9415 or the more ANSI-C compliant forms
9423 can be used synonymously).
9424 Variables declared with this storage class will be allocated in the directly
9425 addressable portion of the internal RAM of a 8051, e.g.:
9430 __data unsigned char test_data;
9433 Writing 0x01 to this variable generates the assembly code:
9438 75*00 01\SpecialChar ~
9444 \layout Subsubsection
9447 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9452 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
9457 \begin_inset LatexCommand \index{far (storage class)}
9462 \begin_inset LatexCommand \index{\_\_far (storage class)}
9469 Variables declared with this storage class will be placed in the external
9475 storage class for the Large Memory model, e.g.:
9480 __xdata unsigned char test_xdata;
9483 Writing 0x01 to this variable generates the assembly code:
9488 90s00r00\SpecialChar ~
9517 \layout Subsubsection
9520 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
9525 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
9532 Variables declared with this storage class will be allocated into the indirectly
9533 addressable portion of the internal ram of a 8051, e.g.:
9538 __idata unsigned char test_idata;
9541 Writing 0x01 to this variable generates the assembly code:
9570 Please note, the first 128 byte of idata physically access the same RAM
9572 The original 8051 had 128 byte idata memory, nowadays most devices have
9573 256 byte idata memory.
9575 \begin_inset LatexCommand \index{stack}
9579 is located in idata memory.
9580 \layout Subsubsection
9583 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
9588 \begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
9595 Paged xdata access is just as straightforward as using the other addressing
9597 It is typically located at the start of xdata and has a maximum size of
9599 The following example writes 0x01 to the pdata variable.
9600 Please note, pdata access physically accesses xdata memory.
9601 The high byte of the address is determined by port P2
9602 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
9606 (or in case of some 8051 variants by a separate Special Function Register,
9608 \begin_inset LatexCommand \ref{sub:MCS51-variants}
9617 storage class for the Medium Memory model, e.g.:
9622 __pdata unsigned char test_pdata;
9625 Writing 0x01 to this variable generates the assembly code:
9669 \begin_inset LatexCommand \index{-\/-xstack}
9673 option is used the pdata memory area is followed by the xstack memory area
9674 and the sum of their sizes is limited to 256 bytes.
9675 \layout Subsubsection
9678 \begin_inset LatexCommand \index{code}
9683 \begin_inset LatexCommand \index{\_\_code}
9690 'Variables' declared with this storage class will be placed in the code
9696 __code unsigned char test_code;
9699 Read access to this variable generates the assembly code:
9704 90s00r6F\SpecialChar ~
9707 mov dptr,#_test_code
9736 indexed arrays of characters in code memory can be accessed efficiently:
9741 __code char test_array[] = {'c','h','e','a','p'};
9744 Read access to this array using an 8-bit unsigned index generates the assembly
9761 90s00r41\SpecialChar ~
9764 mov dptr,#_test_array
9779 \layout Subsubsection
9782 \begin_inset LatexCommand \index{bit}
9787 \begin_inset LatexCommand \index{\_\_bit}
9794 This is a data-type and a storage class specifier.
9795 When a variable is declared as a bit, it is allocated into the bit addressable
9796 memory of 8051, e.g.:
9804 Writing 1 to this variable generates the assembly code:
9820 The bit addressable memory consists of 128 bits which are located from 0x20
9821 to 0x2f in data memory.
9824 Apart from this 8051 specific storage class most architectures support ANSI-C
9826 \begin_inset LatexCommand \index{bitfields}
9836 Not really meant as examples, but nevertheless showing what bitfields are
9837 about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
9841 In accordance with ISO/IEC 9899 bits and bitfields without an explicit
9842 signed modifier are implemented as unsigned.
9843 \layout Subsubsection
9846 \begin_inset LatexCommand \index{sfr}
9851 \begin_inset LatexCommand \index{\_\_sfr}
9856 \begin_inset LatexCommand \index{sfr16}
9861 \begin_inset LatexCommand \index{\_\_sfr16}
9866 \begin_inset LatexCommand \index{sfr32}
9871 \begin_inset LatexCommand \index{\_\_sfr32}
9876 \begin_inset LatexCommand \index{\_\_sbit}
9881 \begin_inset LatexCommand \index{sbit}
9888 Like the bit keyword,
9890 sfr / sfr16 / sfr32 / sbit
9892 signify both a data-type and storage class, they are used to describe the
9913 variables of a 8051, eg:
9919 \begin_inset LatexCommand \index{at}
9924 \begin_inset LatexCommand \index{\_\_at}
9928 (0x80) P0;\SpecialChar ~
9929 /* special function register P0 at location 0x80 */
9933 /* 16 bit special function register combination for timer 0
9937 with the high byte at location 0x8C and the low byte at location 0x8A */
9939 __sfr16 __at (0x8C8A) TMR0;
9944 \begin_inset LatexCommand \index{at}
9949 \begin_inset LatexCommand \index{\_\_at}
9953 (0xd7) CY;\SpecialChar ~
9955 \begin_inset LatexCommand \index{Flags}
9960 \begin_inset LatexCommand \index{Carry flag}
9967 Special function registers which are located on an address dividable by
9968 8 are bit-addressable, an
9972 addresses a specific bit within these sfr.
9974 16 Bit and 32 bit special function register combinations which require a
9975 certain access order are better not declared using
9984 Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
9985 this is not guaranteed.
9990 Please note, if you use a header file which was written for another compiler
9991 then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
9997 Specifically the syntax
10000 sfr P0 = 0x80;\SpecialChar ~
10007 by SDCC to an assignment of 0x80 to a variable called P0
10010 \begin_inset Marginal
10024 Nevertheless it is possible to write header files
10025 \begin_inset LatexCommand \index{Header files}
10030 \begin_inset LatexCommand \index{Include files}
10034 which can be shared among different compilers (see section
10035 \begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}
10041 \layout Subsubsection
10044 \begin_inset LatexCommand \index{Pointer}
10048 to MCS51/DS390 specific memory spaces
10051 SDCC allows (via language extensions) pointers to explicitly point to any
10052 of the memory spaces
10053 \begin_inset LatexCommand \index{Memory model}
10058 In addition to the explicit pointers, the compiler uses (by default) generic
10059 pointers which can be used to point to any of the memory spaces.
10063 Pointer declaration examples:
10068 /* pointer physically in internal ram pointing to object in external ram
10071 __xdata unsigned char * __data p;
10075 /* pointer physically in external ram pointing to object in internal ram
10078 __data unsigned char * __xdata p;
10082 /* pointer physically in code rom pointing to data in xdata space */
10084 __xdata unsigned char * __code p;
10088 /* pointer physically in code space pointing to data in code space */
10090 __code unsigned char * __code p;
10094 /* generic pointer physically located in xdata space */
10096 unsigned char * __xdata p;
10100 /* generic pointer physically located in default memory space */
10106 /* the following is a function pointer
10107 \begin_inset LatexCommand \index{function pointer}
10111 physically located in data space */
10113 char (* __data fp)(void);
10116 Well you get the idea.
10121 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
10134 The highest order byte of the
10138 pointers contains the data space information.
10139 Assembler support routines are called whenever data is stored or retrieved
10145 These are useful for developing reusable library
10146 \begin_inset LatexCommand \index{Libraries}
10151 Explicitly specifying the pointer
10152 \begin_inset LatexCommand \index{pointer}
10156 type will generate the most efficient code.
10157 \layout Subsubsection
10159 Notes on MCS51 memory
10160 \begin_inset LatexCommand \index{MCS51 memory}
10167 The 8051 family of microcontrollers have a minimum of 128 bytes of internal
10168 RAM memory which is structured as follows:
10172 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
10175 - Bytes 20-2F - 16 bytes to hold 128 bit
10176 \begin_inset LatexCommand \index{bit}
10182 - Bytes 30-7F - 80 bytes for general purpose use.
10187 Additionally some members of the MCS51 family may have up to 128 bytes of
10188 additional, indirectly addressable, internal RAM memory (
10193 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
10198 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
10203 Furthermore, some chips may have some built in external memory (
10208 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10213 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10217 ) which should not be confused with the internal, directly addressable RAM
10223 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
10228 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
10233 Sometimes this built in
10237 memory has to be activated before using it (you can probably find this
10238 information on the datasheet of the microcontroller your are using, see
10240 \begin_inset LatexCommand \ref{sub:Startup-Code}
10248 Normally SDCC will only use the first bank
10249 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
10253 of registers (register bank 0), but it is possible to specify that other
10254 banks of registers (keyword
10261 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
10266 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
10272 ) should be used in interrupt
10273 \begin_inset LatexCommand \index{interrupt}
10278 \begin_inset LatexCommand \index{\_\_interrupt}
10283 By default, the compiler will place the stack after the last byte of allocated
10284 memory for variables.
10285 For example, if the first 2 banks of registers are used, and only four
10290 variables, it will position the base of the internal stack at address 20
10292 This implies that as the stack
10293 \begin_inset LatexCommand \index{stack}
10297 grows, it will use up the remaining register banks, and the 16 bytes used
10298 by the 128 bit variables, and 80 bytes for general purpose use.
10299 If any bit variables are used, the data variables will be placed in unused
10300 register banks and after the byte holding the last bit variable.
10301 For example, if register banks 0 and 1 are used, and there are 9 bit variables
10306 variables will be placed starting from address 0x10 to 0x20 and continue
10319 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
10323 to specify the start address of the
10338 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
10342 to specify the size of the total internal RAM (
10356 By default the 8051 linker will place the stack after the last byte of (i)data
10369 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
10373 allows you to specify the start of the stack, i.e.
10374 you could start it after any data in the general purpose area.
10375 If your microcontroller has additional indirectly addressable internal
10380 ) you can place the stack on it.
10381 You may also need to use -
10392 \begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
10396 to set the start address of the external RAM (
10411 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
10415 to specify its size.
10416 Same goes for the code memory, using -
10427 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
10442 \begin_inset LatexCommand \index{-\/-code-size <Value>}
10447 If in doubt, don't specify any options and see if the resulting memory
10448 layout is appropriate, then you can adjust it.
10450 \added_space_bottom bigskip
10451 The linker generates two files with memory allocation information.
10452 The first, with extension .map
10453 \begin_inset LatexCommand \index{<file>.map}
10457 shows all the variables and segments.
10458 The second with extension .mem
10459 \begin_inset LatexCommand \index{<file>.mem}
10463 shows the final memory layout.
10464 The linker will complain either if memory segments overlap, there is not
10465 enough memory, or there is not enough space for stack.
10466 If you get any linking warnings and/or errors related to stack or segments
10467 allocation, take a look at either the .map or .mem files to find out what
10469 The .mem file may even suggest a solution to the problem.
10472 Z80/Z180 Storage Class
10473 \begin_inset LatexCommand \index{Z80!Storage class}
10477 Language Extensions
10478 \layout Subsubsection
10481 \begin_inset LatexCommand \index{sfr}
10486 \begin_inset LatexCommand \index{\_\_sfr}
10490 (in/out to 8-bit addresses)
10494 \begin_inset LatexCommand \index{Z80}
10498 family has separate address spaces for memory and
10508 \begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
10513 \begin_inset LatexCommand \index{Z80!I/O memory}
10518 \begin_inset LatexCommand \index{Z180!I/O memory}
10522 is accessed with special instructions, e.g.:
10527 sfr at 0x78 IoPort;\SpecialChar ~
10529 /* define a var in I/O space at 78h called IoPort */
10533 Writing 0x01 to this variable generates the assembly code:
10538 3E 01\SpecialChar ~
10546 D3 78\SpecialChar ~
10553 \layout Subsubsection
10556 \begin_inset LatexCommand \index{sfr}
10561 \begin_inset LatexCommand \index{\_\_sfr}
10565 (in/out to 16-bit addresses)
10572 is used to support 16 bit addresses in I/O memory e.g.:
10578 \begin_inset LatexCommand \index{at}
10583 \begin_inset LatexCommand \index{\_\_at}
10590 Writing 0x01 to this variable generates the assembly code:
10595 01 23 01\SpecialChar ~
10600 3E 01\SpecialChar ~
10608 ED 79\SpecialChar ~
10615 \layout Subsubsection
10618 \begin_inset LatexCommand \index{sfr}
10623 \begin_inset LatexCommand \index{\_\_sfr}
10627 (in0/out0 to 8 bit addresses on Z180
10628 \begin_inset LatexCommand \index{Z180}
10633 \begin_inset LatexCommand \index{HD64180 (see Z180)}
10639 \added_space_bottom bigskip
10640 The compiler option -
10651 \begin_inset LatexCommand \index{Z180!Options!-\/-portmode}
10655 =180 (80) and a compiler #pragma\SpecialChar ~
10657 \begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}
10661 =z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
10671 If you include the file z180.h this will be set automatically.
10675 \begin_inset LatexCommand \index{HC08!Storage class}
10679 Language Extensions
10680 \layout Subsubsection
10683 \begin_inset LatexCommand \index{data (hc08 storage class)}
10688 \begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
10695 The data storage class declares a variable that resides in the first 256
10696 bytes of memory (the direct page).
10698 \begin_inset LatexCommand \index{HC08}
10702 is most efficient at accessing variables (especially pointers) stored here.
10703 \layout Subsubsection
10706 \begin_inset LatexCommand \index{xdata (hc08 storage class)}
10711 \begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
10717 \added_space_bottom bigskip
10718 The xdata storage class declares a variable that can reside anywhere in
10720 This is the default if no storage class is specified.
10724 Absolute Addressing
10725 \begin_inset LatexCommand \index{Absolute addressing}
10732 Data items can be assigned an absolute address with the
10735 \begin_inset LatexCommand \index{at}
10740 \begin_inset LatexCommand \index{\_\_at}
10746 keyword, in addition to a storage class, e.g.:
10752 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10757 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10762 \begin_inset LatexCommand \index{at}
10767 \begin_inset LatexCommand \index{\_\_at}
10771 0x7ffe unsigned int chksum;
10774 or, better conforming to ISO/IEC 9899 C:
10779 __xdata __at (0x7ffe) unsigned int chksum;
10782 In the above example the variable chksum will be located at 0x7ffe and 0x7fff
10783 of the external ram.
10788 reserve any space for variables declared in this way
10789 \begin_inset Marginal
10800 (they are implemented with an equate in the assembler).
10801 Thus it is left to the programmer to make sure there are no overlaps with
10802 other variables that are declared without the absolute address.
10803 The assembler listing file (.lst
10804 \begin_inset LatexCommand \index{<file>.lst}
10808 ) and the linker output files (.rst
10809 \begin_inset LatexCommand \index{<file>.rst}
10814 \begin_inset LatexCommand \index{<file>.map}
10818 ) are good places to look for such overlaps.
10819 Variables with an absolute address are
10822 \begin_inset Marginal
10836 \begin_inset LatexCommand \index{Variable initialization}
10843 In case of memory mapped I/O devices the keyword
10847 has to be used to tell the compiler that accesses might not be removed:
10853 \begin_inset LatexCommand \index{volatile}
10858 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10863 \begin_inset LatexCommand \index{at}
10867 (0x8000) unsigned char PORTA_8255;
10870 For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
10875 \begin_inset LatexCommand \index{Aligned array}
10882 starts at a block (256 byte) boundary
10883 \begin_inset LatexCommand \index{block boundary}
10888 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
10894 Absolute addresses can be specified for variables in all storage classes,
10901 \begin_inset LatexCommand \index{bit}
10906 \begin_inset LatexCommand \index{at}
10913 The above example will allocate the variable at offset 0x02 in the bit-addressab
10915 There is no real advantage to assigning absolute addresses to variables
10916 in this manner, unless you want strict control over all the variables allocated.
10917 One possible use would be to write hardware portable code.
10918 For example, if you have a routine that uses one or more of the microcontroller
10919 I/O pins, and such pins are different for two different hardwares, you
10920 can declare the I/O pins in your routine using:
10926 \begin_inset LatexCommand \index{volatile}
10930 __bit MOSI;\SpecialChar ~
10934 /* master out, slave in */
10936 extern volatile __bit MISO;\SpecialChar ~
10940 /* master in, slave out */
10942 extern volatile __bit MCLK;\SpecialChar ~
10950 /* Input and Output of a byte on a 3-wire serial bus.
10955 If needed adapt polarity of clock, polarity of data and bit order
10960 unsigned char spi_io(unsigned char out_byte)
10984 MOSI = out_byte & 0x80;
11014 /* _asm nop _endasm; */\SpecialChar ~
11022 /* for slow peripherals */
11073 Then, someplace in the code for the first hardware you would use
11079 \begin_inset LatexCommand \index{at}
11084 \begin_inset LatexCommand \index{\_\_at}
11088 (0x80) MOSI;\SpecialChar ~
11092 /* I/O port 0, bit 0 */
11094 __bit __at (0x81) MISO;\SpecialChar ~
11098 /* I/O port 0, bit 1 */
11100 __bit __at (0x82) MCLK;\SpecialChar ~
11104 /* I/O port 0, bit 2 */
11107 Similarly, for the second hardware you would use
11112 __bit __at (0x83) MOSI;\SpecialChar ~
11116 /* I/O port 0, bit 3 */
11118 __bit __at (0x91) MISO;\SpecialChar ~
11122 /* I/O port 1, bit 1 */
11125 \begin_inset LatexCommand \index{bit}
11129 __at (0x92) MCLK;\SpecialChar ~
11133 /* I/O port 1, bit 2 */
11135 \added_space_bottom bigskip
11136 and you can use the same hardware dependent routine without changes, as
11137 for example in a library.
11138 This is somehow similar to sbit, but only one absolute address has to be
11139 specified in the whole project.
11143 \begin_inset LatexCommand \index{Parameters}
11148 \begin_inset LatexCommand \index{function parameter}
11153 \begin_inset LatexCommand \index{local variables}
11158 \begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
11165 Automatic (local) variables and parameters to functions can either be placed
11166 on the stack or in data-space.
11167 The default action of the compiler is to place these variables in the internal
11168 RAM (for small model) or external RAM (for large model).
11169 This in fact makes them similar to
11172 \begin_inset LatexCommand \index{static}
11178 so by default functions are non-reentrant
11179 \begin_inset LatexCommand \index{reentrant}
11188 They can be placed on the stack
11189 \begin_inset LatexCommand \index{stack}
11206 \begin_inset LatexCommand \index{-\/-stack-auto}
11214 #pragma\SpecialChar ~
11218 \begin_inset LatexCommand \index{\#pragma stackauto}
11225 \begin_inset LatexCommand \index{reentrant}
11231 keyword in the function declaration, e.g.:
11236 unsigned char foo(char i) __reentrant
11250 Since stack space on 8051 is limited, the
11268 option should be used sparingly.
11269 Note that the reentrant keyword just means that the parameters & local
11270 variables will be allocated to the stack, it
11274 mean that the function is register bank
11275 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
11284 \begin_inset LatexCommand \index{local variables}
11288 can be assigned storage classes and absolute
11289 \begin_inset LatexCommand \index{Absolute addressing}
11298 unsigned char foo()
11306 __xdata unsigned char i;
11319 \begin_inset LatexCommand \index{at}
11323 (0x31) unsigned char j;
11335 In the above example the variable
11339 will be allocated in the external ram,
11343 in bit addressable space and
11362 or when a function is declared as
11366 this should only be done for static variables.
11370 \begin_inset LatexCommand \index{function parameter}
11374 however are not allowed any storage class
11375 \begin_inset LatexCommand \index{Storage class}
11379 , (storage classes for parameters will be ignored), their allocation is
11380 governed by the memory model in use, and the reentrancy options.
11383 It is however allowed to use bit parameters in reentrant functions and also
11384 non-static local bit variables are supported.
11385 Efficient use is limited to 8 semi-bitregisters in bit space.
11386 They are pushed and popped to stack
11387 \begin_inset LatexCommand \index{stack}
11391 as a single byte just like the normal registers.
11395 \begin_inset LatexCommand \label{sub:Overlaying}
11400 \begin_inset LatexCommand \index{Overlaying}
11408 \begin_inset LatexCommand \index{reentrant}
11412 functions SDCC will try to reduce internal ram space usage by overlaying
11413 parameters and local variables of a function (if possible).
11414 Parameters and local variables
11415 \begin_inset LatexCommand \index{local variables}
11419 of a function will be allocated to an overlayable segment if the function
11422 no other function calls and the function is non-reentrant and the memory
11424 \begin_inset LatexCommand \index{Memory model}
11431 If an explicit storage class
11432 \begin_inset LatexCommand \index{Storage class}
11436 is specified for a local variable, it will NOT be overlayed.
11439 Note that the compiler (not the linkage editor) makes the decision for overlayin
11441 Functions that are called from an interrupt service routine
11442 \begin_inset Marginal
11452 should be preceded by a #pragma\SpecialChar ~
11454 \begin_inset LatexCommand \index{\#pragma nooverlay}
11458 if they are not reentrant.
11461 Also note that the compiler does not do any processing of inline assembler
11462 code, so the compiler might incorrectly assign local variables and parameters
11463 of a function into the overlay segment if the inline assembler code calls
11464 other c-functions that might use the overlay.
11465 In that case the #pragma\SpecialChar ~
11466 nooverlay should be used.
11469 Parameters and local variables of functions that contain 16 or 32 bit multiplica
11471 \begin_inset LatexCommand \index{Multiplication}
11476 \begin_inset LatexCommand \index{Division}
11480 will NOT be overlayed since these are implemented using external functions,
11489 \begin_inset LatexCommand \index{\#pragma nooverlay}
11495 void set_error(unsigned char errcd)
11511 void some_isr () __interrupt
11512 \begin_inset LatexCommand \index{interrupt}
11541 \added_space_bottom bigskip
11542 In the above example the parameter
11550 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
11552 not present, this could cause unpredictable runtime behavior when called
11553 from an interrupt service routine.
11554 The #pragma\SpecialChar ~
11555 nooverlay ensures that the parameters and local variables for
11556 the function are NOT overlayed.
11559 Interrupt Service Routines
11560 \begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
11567 General Information
11582 outines to be coded in C, with some extended keywords.
11587 void timer_isr (void) __interrupt (1) __using (1)
11601 The optional number following the
11604 \begin_inset LatexCommand \index{interrupt}
11609 \begin_inset LatexCommand \index{\_\_interrupt}
11615 keyword is the interrupt number this routine will service.
11616 When present, the compiler will insert a call to this routine in the interrupt
11618 \begin_inset LatexCommand \index{interrupt vector table}
11622 for the interrupt number specified.
11623 If you have multiple source files in your project, interrupt service routines
11624 can be present in any of them, but a prototype of the isr MUST be present
11625 or included in the file that contains the function
11630 The optional (8051 specific) keyword
11633 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
11638 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
11644 can be used to tell the compiler to use the specified register bank when
11645 generating code for this function.
11648 Interrupt service routines open the door for some very interesting bugs:
11649 \layout Subsubsection
11652 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}
11656 Common interrupt pitfall: variable not declared
11661 If an interrupt service routine changes variables which are accessed by
11662 other functions these variables have to be declared
11667 \begin_inset LatexCommand \index{volatile}
11673 \begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}
11678 \layout Subsubsection
11681 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}
11685 Common interrupt pitfall:
11690 If the access to these variables is not
11693 \begin_inset LatexCommand \index{atomic}
11700 the processor needs more than one instruction for the access and could
11701 be interrupted while accessing the variable) the interrupt must be disabled
11702 during the access to avoid inconsistent data.
11705 Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs and
11706 should be protected by disabling interrupts.
11707 You're not automatically on the safe side if you use 8 bit variables though.
11708 We need an example here: f.e.
11709 on the 8051 the harmless looking
11710 \begin_inset Quotes srd
11715 flags\SpecialChar ~
11720 \begin_inset Quotes sld
11729 \begin_inset Quotes srd
11734 flags\SpecialChar ~
11739 \begin_inset Quotes sld
11742 from within an interrupt routine might get lost if the interrupt occurs
11745 \begin_inset Quotes sld
11750 counter\SpecialChar ~
11755 \begin_inset Quotes srd
11758 is not atomic on the 8051 even if
11762 is located in data memory.
11764 Bugs like these are hard to reproduce and can cause a lot of trouble.
11766 \layout Subsubsection
11769 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}
11773 Common interrupt pitfall:
11778 The return address and the registers used in the interrupt service routine
11779 are saved on the stack
11780 \begin_inset LatexCommand \index{stack}
11784 so there must be sufficient stack space.
11785 If there isn't variables or registers (or even the return address itself)
11792 \begin_inset LatexCommand \index{stack overflow}
11796 is most likely to happen if the interrupt occurs during the
11797 \begin_inset Quotes sld
11801 \begin_inset Quotes srd
11804 subroutine when the stack is already in use for f.e.
11805 many return addresses.
11806 \layout Subsubsection
11809 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}
11813 Common interrupt pitfall:
11815 use of non-reentrant functions
11818 A special note here, int (16 bit) and long (32 bit) integer division
11819 \begin_inset LatexCommand \index{Division}
11824 \begin_inset LatexCommand \index{Multiplication}
11829 \begin_inset LatexCommand \index{Modulus}
11834 \begin_inset LatexCommand \index{Floating point support}
11838 operations are implemented using external support routines.
11839 If an interrupt service routine needs to do any of these operations then
11840 the support routines (as mentioned in a following section) will have to
11841 be recompiled using the
11854 \begin_inset LatexCommand \index{-\/-stack-auto}
11860 option and the source file will need to be compiled using the
11875 \begin_inset LatexCommand \index{-\/-int-long-reent}
11882 Note, the type promotion
11883 \begin_inset LatexCommand \index{type promotion}
11887 required by ANSI C can cause 16 bit routines to be used
11888 \begin_inset Marginal
11899 without the programmer being aware of it.
11903 (unsigned char)(tail-1)
11905 within the if clause in section
11906 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
11912 \added_space_bottom bigskip
11913 Calling other functions from an interrupt service routine is not recommended,
11914 avoid it if possible.
11915 Note that when some function is called from an interrupt service routine
11916 it should be preceded by a #pragma\SpecialChar ~
11918 \begin_inset LatexCommand \index{\#pragma nooverlay}
11922 if it is not reentrant.
11923 Furthermore nonreentrant functions should not be called from the main program
11924 while the interrupt service routine might be active.
11925 They also must not be called from low priority interrupt service routines
11926 while a high priority interrupt service routine might be active.
11927 You could use semaphores or make the function
11931 if all parameters are passed in registers.
11934 \begin_inset LatexCommand \ref{sub:Overlaying}
11939 about Overlaying and section
11940 \begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
11945 about Functions using private register banks.
11948 MCS51/DS390 Interrupt Service Routines
11952 \begin_inset LatexCommand \index{interrupt}
11956 numbers and the corresponding address & descriptions for the Standard 8051/8052
11958 SDCC will automatically adjust the
11959 \begin_inset LatexCommand \index{interrupt vector table}
11963 to the maximum interrupt number specified.
11969 \begin_inset Tabular
11970 <lyxtabular version="3" rows="9" columns="3">
11972 <column alignment="center" valignment="top" leftline="true" width="0in">
11973 <column alignment="left" valignment="top" leftline="true" width="0in">
11974 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
11975 <row topline="true" bottomline="true">
11976 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11984 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11992 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12001 <row topline="true">
12002 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12010 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12018 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12027 <row topline="true">
12028 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12036 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12044 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12053 <row topline="true">
12054 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12062 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12070 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12079 <row topline="true">
12080 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12088 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12096 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12105 <row topline="true">
12106 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12114 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12122 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12131 <row topline="true">
12132 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12140 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12148 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12157 <row topline="true">
12158 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12166 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12173 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12182 <row topline="true" bottomline="true">
12183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12191 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12198 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12216 If the interrupt service routine is defined without
12219 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12224 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12230 a register bank or with register bank 0 (
12234 0), the compiler will save the registers used by itself on the stack upon
12235 entry and restore them at exit, however if such an interrupt service routine
12236 calls another function then the entire register bank will be saved on the
12238 This scheme may be advantageous for small interrupt service routines which
12239 have low register usage.
12241 \added_space_bottom bigskip
12242 If the interrupt service routine is defined to be using a specific register
12247 & psw are saved and restored, if such an interrupt service routine calls
12248 another function (using another register bank) then the entire register
12249 bank of the called function will be saved on the stack
12250 \begin_inset LatexCommand \index{stack}
12255 This scheme is recommended for larger interrupt service routines.
12259 \begin_inset LatexCommand \index{HC08}
12263 Interrupt Service Routines
12265 \added_space_bottom bigskip
12266 Since the number of interrupts
12267 \begin_inset LatexCommand \index{HC08!interrupt}
12271 available is chip specific and the interrupt vector table always ends at
12272 the last byte of memory, the interrupt numbers corresponds to the interrupt
12273 vectors in reverse order of address.
12274 For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
12275 2 will use the interrupt vector at 0xfffa, and so on.
12276 However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
12277 this way; instead see section
12278 \begin_inset LatexCommand \ref{sub:Startup-Code}
12282 for details on customizing startup.
12285 Z80 Interrupt Service Routines
12289 \begin_inset LatexCommand \index{Z80}
12293 uses several different methods for determining the correct interrupt
12294 \begin_inset LatexCommand \index{Z80!interrupt}
12298 vector depending on the hardware implementation.
12299 Therefore, SDCC ignores the optional interrupt number and does not attempt
12300 to generate an interrupt vector table.
12303 By default, SDCC generates code for a maskable interrupt, which uses a RETI
12304 instruction to return from the interrupt.
12305 To write an interrupt handler for the non-maskable interrupt, which needs
12306 a RETN instruction instead, add the
12315 void nmi_isr (void) critical interrupt
12328 \added_space_bottom bigskip
12329 However if you need to create a non-interruptable interrupt service routine
12330 you would also require the
12335 To distinguish between this and an nmi_isr you must provide an interrupt
12339 Enabling and Disabling Interrupts
12342 Critical Functions and Critical Statements
12345 A special keyword may be associated with a block or a function declaring
12351 SDCC will generate code to disable all interrupts
12352 \begin_inset LatexCommand \index{interrupt}
12356 upon entry to a critical function and restore the interrupt enable to the
12357 previous state before returning.
12358 Nesting critical functions will need one additional byte on the stack
12359 \begin_inset LatexCommand \index{stack}
12368 int foo () __critical
12369 \begin_inset LatexCommand \index{critical}
12374 \begin_inset LatexCommand \index{\_\_critical}
12399 The critical attribute maybe used with other attributes like
12409 may also be used to disable interrupts more locally:
12417 More than one statement could have been included in the block.
12420 Enabling and Disabling Interrupts directly
12424 \begin_inset LatexCommand \index{interrupt}
12428 can also be disabled and enabled directly (8051):
12433 EA = 0;\SpecialChar ~
12496 EA = 1;\SpecialChar ~
12563 On other architectures which have seperate opcodes for enabling and disabling
12564 interrupts you might want to make use of defines with inline assembly
12565 \begin_inset LatexCommand \index{Assembler routines}
12570 \begin_inset LatexCommand \index{HC08!interrupt}
12580 \begin_inset LatexCommand \index{\_asm}
12589 \begin_inset LatexCommand \index{\_endasm}
12598 #define SEI _asm\SpecialChar ~
12610 Note: it is sometimes sufficient to disable only a specific interrupt source
12612 a timer or serial interrupt by manipulating an
12615 \begin_inset LatexCommand \index{interrupt mask}
12625 Usually the time during which interrupts are disabled should be kept as
12627 This minimizes both
12632 \begin_inset LatexCommand \index{interrupt latency}
12636 (the time between the occurrence of the interrupt and the execution of
12637 the first code in the interrupt routine) and
12642 \begin_inset LatexCommand \index{interrupt jitter}
12646 (the difference between the shortest and the longest interrupt latency).
12647 These really are something different, f.e.
12648 a serial interrupt has to be served before its buffer overruns so it cares
12649 for the maximum interrupt latency, whereas it does not care about jitter.
12650 On a loudspeaker driven via a digital to analog converter which is fed
12651 by an interrupt a latency of a few milliseconds might be tolerable, whereas
12652 a much smaller jitter will be very audible.
12655 You can reenable interrupts within an interrupt routine and on some architecture
12656 s you can make use of two (or more) levels of
12658 interrupt priorities
12661 \begin_inset LatexCommand \index{interrupt priority}
12666 On some architectures which don't support interrupt priorities these can
12667 be implemented by manipulating the interrupt mask and reenabling interrupts
12668 within the interrupt routine.
12669 Check there is sufficient space on the stack
12670 \begin_inset LatexCommand \index{stack}
12674 and don't add complexity unless you have to.
12679 \begin_inset LatexCommand \index{semaphore}
12683 locking (mcs51/ds390)
12686 Some architectures (mcs51/ds390) have an atomic
12687 \begin_inset LatexCommand \index{atomic}
12700 These type of instructions are typically used in preemptive multitasking
12701 systems, where a routine f.e.
12702 claims the use of a data structure ('acquires a lock
12703 \begin_inset LatexCommand \index{lock}
12707 on it'), makes some modifications and then releases the lock when the data
12708 structure is consistent again.
12709 The instruction may also be used if interrupt and non-interrupt code have
12710 to compete for a resource.
12711 With the atomic bit test and clear instruction interrupts
12712 \begin_inset LatexCommand \index{interrupt}
12716 don't have to be disabled for the locking operation.
12720 SDCC generates this instruction if the source follows this pattern:
12726 \begin_inset LatexCommand \index{volatile}
12730 bit resource_is_free;
12734 if (resource_is_free)
12744 resource_is_free=0;
12757 resource_is_free=1;
12764 Note, mcs51 and ds390 support only an atomic
12765 \begin_inset LatexCommand \index{atomic}
12773 instruction (as opposed to atomic bit test and
12778 Functions using private register banks
12779 \begin_inset LatexCommand \label{sub:Functions-using-private-banks}
12786 Some architectures have support for quickly changing register sets.
12787 SDCC supports this feature with the
12790 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12795 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12801 attribute (which tells the compiler to use a register bank
12802 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
12806 other than the default bank zero).
12807 It should only be applied to
12810 \begin_inset LatexCommand \index{interrupt}
12816 functions (see footnote below).
12817 This will in most circumstances make the generated ISR code more efficient
12818 since it will not have to save registers on the stack.
12825 attribute will have no effect on the generated code for a
12829 function (but may occasionally be useful anyway
12835 possible exception: if a function is called ONLY from 'interrupt' functions
12836 using a particular bank, it can be declared with the same 'using' attribute
12837 as the calling 'interrupt' functions.
12838 For instance, if you have several ISRs using bank one, and all of them
12839 call memcpy(), it might make sense to create a specialized version of memcpy()
12840 'using 1', since this would prevent the ISR from having to save bank zero
12841 to the stack on entry and switch to bank zero before calling the function
12848 (pending: Note, nowadays the
12852 attribute has an effect on
12856 the generated code for a
12871 function using a non-zero bank will assume that it can trash that register
12872 bank, and will not save it.
12873 Since high-priority interrupts
12874 \begin_inset LatexCommand \index{interrupts}
12879 \begin_inset LatexCommand \index{interrupt priority}
12883 can interrupt low-priority ones on the 8051 and friends, this means that
12884 if a high-priority ISR
12888 a particular bank occurs while processing a low-priority ISR
12892 the same bank, terrible and bad things can happen.
12893 To prevent this, no single register bank should be
12897 by both a high priority and a low priority ISR.
12898 This is probably most easily done by having all high priority ISRs use
12899 one bank and all low priority ISRs use another.
12900 If you have an ISR which can change priority at runtime, you're on your
12901 own: I suggest using the default bank zero and taking the small performance
12904 \added_space_bottom bigskip
12905 It is most efficient if your ISR calls no other functions.
12906 If your ISR must call other functions, it is most efficient if those functions
12907 use the same bank as the ISR (see note 1 below); the next best is if the
12908 called functions use bank zero.
12909 It is very inefficient to call a function using a different, non-zero bank
12915 \begin_inset LatexCommand \label{sub:Startup-Code}
12920 \begin_inset LatexCommand \index{Startup code}
12927 MCS51/DS390 Startup Code
12930 The compiler inserts a call to the C routine
12932 _sdcc_external_startup()
12933 \begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
12942 at the start of the CODE area.
12943 This routine is in the runtime library
12944 \begin_inset LatexCommand \index{Runtime library}
12949 By default this routine returns 0, if this routine returns a non-zero value,
12950 the static & global variable initialization will be skipped and the function
12951 main will be invoked.
12952 Otherwise static & global variables will be initialized before the function
12956 _sdcc_external_startup()
12958 routine to your program to override the default if you need to setup hardware
12959 or perform some other critical operation prior to static & global variable
12961 \begin_inset LatexCommand \index{Variable initialization}
12966 On some mcs51 variants xdata
12967 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
12971 memory has to be explicitly enabled before it can be accessed or if the
12973 \begin_inset LatexCommand \index{watchdog}
12977 needs to be disabled, this is the place to do it.
12978 The startup code clears all internal data memory, 256 bytes by default,
12979 but from 0 to n-1 if
12992 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
12999 (recommended for Chipcon CC1010).
13001 \added_space_bottom bigskip
13002 See also the compiler options
13021 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
13040 \begin_inset LatexCommand \index{-\/-main-return}
13045 \begin_inset LatexCommand \ref{sub:MCS51-variants}
13049 about MCS51-variants.
13054 \added_space_bottom bigskip
13056 \begin_inset LatexCommand \index{HC08}
13060 startup code follows the same scheme as the MCS51 startup code.
13065 \added_space_bottom bigskip
13067 \begin_inset LatexCommand \index{Z80}
13071 the startup code is inserted by linking with crt0.o which is generated from
13072 sdcc/device/lib/z80/crt0.s.
13073 If you need a different startup code you can use the compiler option
13094 \begin_inset LatexCommand \index{-\/-no-std-crt0}
13098 and provide your own crt0.o.
13102 Inline Assembler Code
13103 \begin_inset LatexCommand \index{Assembler routines}
13110 A Step by Step Introduction
13111 \begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}
13118 Starting from a small snippet of c-code this example shows for the MCS51
13119 how to use inline assembly, access variables, a function parameter and
13120 an array in xdata memory.
13121 The example uses an MCS51 here but is easily adapted for other architectures.
13122 This is a buffer routine which should be optimized:
13128 unsigned char __far
13129 \begin_inset LatexCommand \index{far (storage class)}
13134 \begin_inset LatexCommand \index{\_\_far (storage class)}
13139 \begin_inset LatexCommand \index{at}
13144 \begin_inset LatexCommand \index{\_\_at}
13148 (0x7f00) buf[0x100];
13149 \begin_inset LatexCommand \index{Aligned array}
13155 unsigned char head, tail;\SpecialChar ~
13173 \begin_inset LatexCommand \index{interrupt}
13225 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
13237 void to_buffer( unsigned char c )
13245 if( head != (unsigned char)(tail-1) )\SpecialChar ~
13251 \begin_inset LatexCommand \index{promotion to signed int}
13256 \begin_inset LatexCommand \index{type promotion}
13261 \begin_inset Marginal
13282 buf[ head++ ] = c;\SpecialChar ~
13298 /* access to a 256 byte aligned array */
13303 If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
13304 then a corresponding buffer.asm file is generated.
13305 We define a new function
13309 in file buffer.c in which we cut and paste the generated code, removing
13310 unwanted comments and some ':'.
13312 \begin_inset Quotes sld
13316 \begin_inset Quotes srd
13320 \begin_inset Quotes sld
13324 \begin_inset Quotes srd
13327 to the beginning and the end of the function body:
13333 /* With a cut and paste from the .asm file, we have something to start with.
13338 The function is not yet OK! (registers aren't saved) */
13340 void to_buffer_asm( unsigned char c )
13349 \begin_inset LatexCommand \index{\_asm}
13354 \begin_inset LatexCommand \index{\_\_asm}
13368 ;buffer.c if( head != (unsigned char)(tail-1) ) \SpecialChar ~
13374 \begin_inset LatexCommand \index{promotion to signed int}
13379 \begin_inset LatexCommand \index{type promotion}
13431 ;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
13432 \begin_inset LatexCommand \index{Aligned array}
13497 \begin_inset LatexCommand \index{\_endasm}
13502 \begin_inset LatexCommand \index{\_\_endasm}
13511 The new file buffer.c should compile with only one warning about the unreferenced
13512 function argument 'c'.
13513 Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
13514 (1) and finally have:
13520 unsigned char __far __at(0x7f00) buf[0x100];
13522 unsigned char head, tail;
13524 #define USE_ASSEMBLY (1)
13532 void to_buffer( unsigned char c )
13540 if( head != (unsigned char)(tail-1) )
13560 void to_buffer( unsigned char c )
13568 c; // to avoid warning: unreferenced function argument
13575 \begin_inset LatexCommand \index{\_asm}
13580 \begin_inset LatexCommand \index{\_\_asm}
13594 ; save used registers here.
13605 ; If we were still using r2,r3 we would have to push them here.
13608 ; if( head != (unsigned char)(tail-1) )
13651 ; we could do an ANL a,#0x0f here to use a smaller buffer (see below)
13675 ; buf[ head++ ] = c;
13686 a,dpl \SpecialChar ~
13693 ; dpl holds lower byte of function argument
13704 dpl,_head \SpecialChar ~
13707 ; buf is 0x100 byte aligned so head can be used directly
13749 ; we could do an ANL _head,#0x0f here to use a smaller buffer (see above)
13761 ; restore used registers here
13768 \begin_inset LatexCommand \index{\_endasm}
13773 \begin_inset LatexCommand \index{\_\_endasm}
13784 The inline assembler code can contain any valid code understood by the assembler
13785 , this includes any assembler directives and comment lines.
13786 The assembler does not like some characters like ':' or ''' in comments.
13787 You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
13788 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
13793 \begin_inset LatexCommand \index{Assembler documentation}
13798 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
13806 The compiler does not do any validation of the code within the
13809 \begin_inset LatexCommand \index{\_asm}
13814 \begin_inset LatexCommand \index{\_\_asm}
13822 \begin_inset LatexCommand \index{\_endasm}
13827 \begin_inset LatexCommand \index{\_\_endasm}
13836 Specifically it will not know which registers are used and thus register
13838 \begin_inset LatexCommand \index{push/pop}
13842 has to be done manually.
13846 It is recommended that each assembly instruction (including labels) be placed
13847 in a separate line (as the example shows).
13861 \begin_inset LatexCommand \index{-\/-peep-asm}
13867 command line option is used, the inline assembler code will be passed through
13868 the peephole optimizer
13869 \begin_inset LatexCommand \index{Peephole optimizer}
13874 There are only a few (if any) cases where this option makes sense, it might
13875 cause some unexpected changes in the inline assembler code.
13876 Please go through the peephole optimizer rules defined in file
13880 before using this option.
13884 \begin_inset LatexCommand \label{sub:Naked-Functions}
13889 \begin_inset LatexCommand \index{Naked functions}
13896 A special keyword may be associated with a function declaring it as
13899 \begin_inset LatexCommand \index{\_naked}
13904 \begin_inset LatexCommand \index{\_\_naked}
13915 function modifier attribute prevents the compiler from generating prologue
13916 \begin_inset LatexCommand \index{function prologue}
13921 \begin_inset LatexCommand \index{function epilogue}
13925 code for that function.
13926 This means that the user is entirely responsible for such things as saving
13927 any registers that may need to be preserved, selecting the proper register
13928 bank, generating the
13932 instruction at the end, etc.
13933 Practically, this means that the contents of the function must be written
13934 in inline assembler.
13935 This is particularly useful for interrupt functions, which can have a large
13936 (and often unnecessary) prologue/epilogue.
13937 For example, compare the code generated by these two functions:
13943 \begin_inset LatexCommand \index{volatile}
13947 data unsigned char counter;
13951 void simpleInterrupt(void) __interrupt
13952 \begin_inset LatexCommand \index{interrupt}
13957 \begin_inset LatexCommand \index{\_\_interrupt}
13975 void nakedInterrupt(void) __interrupt (2) __naked
13984 \begin_inset LatexCommand \index{\_asm}
13989 \begin_inset LatexCommand \index{\_\_asm}
14006 _counter ; does not change flags, no need to save psw
14018 ; MUST explicitly include ret or reti in _naked function.
14025 \begin_inset LatexCommand \index{\_endasm}
14030 \begin_inset LatexCommand \index{\_\_endasm}
14039 For an 8051 target, the generated simpleInterrupt looks like:
14048 example, recent versions of SDCC generate
14054 code for simpleInterrupt() and nakedInterrupt()!
14194 whereas nakedInterrupt looks like:
14209 _counter ; does not change flags, no need to save psw
14227 ; MUST explicitly include ret or reti in _naked function
14230 The related directive #pragma exclude
14231 \begin_inset LatexCommand \index{\#pragma exclude}
14235 allows a more fine grained control over pushing & popping
14236 \begin_inset LatexCommand \index{push/pop}
14243 While there is nothing preventing you from writing C code inside a
14247 function, there are many ways to shoot yourself in the foot doing this,
14248 and it is recommended that you stick to inline assembler.
14251 Use of Labels within Inline Assembler
14254 SDCC allows the use of in-line assembler with a few restrictions regarding
14256 In older versions of the compiler all labels defined within inline assembler
14265 where nnnn is a number less than 100 (which implies a limit of utmost 100
14266 inline assembler labels
14280 \begin_inset LatexCommand \index{\_asm}
14285 \begin_inset LatexCommand \index{\_\_asm}
14315 \begin_inset LatexCommand \index{\_endasm}
14320 \begin_inset LatexCommand \index{\_\_endasm}
14327 Inline assembler code cannot reference any C-Labels, however it can reference
14329 \begin_inset LatexCommand \index{Labels}
14333 defined by the inline assembler, e.g.:
14358 ; some assembler code
14378 /* some more c code */
14380 clabel:\SpecialChar ~
14382 /* inline assembler cannot reference this label */
14394 $0003: ;label (can be referenced by inline assembler only)
14401 \begin_inset LatexCommand \index{\_endasm}
14406 \begin_inset LatexCommand \index{\_\_endasm}
14416 /* some more c code */
14421 In other words inline assembly code can access labels defined in inline
14422 assembly within the scope of the function.
14423 The same goes the other way, i.e.
14424 labels defines in inline assembly can not be accessed by C statements.
14427 Interfacing with Assembler Code
14428 \begin_inset LatexCommand \index{Assembler routines}
14435 Global Registers used for Parameter Passing
14436 \begin_inset LatexCommand \index{Parameter passing}
14443 The compiler always uses the global registers
14446 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14451 \begin_inset LatexCommand \index{DPTR}
14456 \begin_inset LatexCommand \index{B (mcs51, ds390 register)}
14465 \begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}
14471 to pass the first parameter to a routine.
14472 The second parameter onwards is either allocated on the stack (for reentrant
14483 -stack-auto is used) or in data / xdata memory (depending on the memory
14488 Assembler Routine (non-reentrant)
14491 In the following example
14492 \begin_inset LatexCommand \index{reentrant}
14497 \begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
14501 the function c_func calls an assembler routine asm_func, which takes two
14503 \begin_inset LatexCommand \index{function parameter}
14512 extern int asm_func(unsigned char, unsigned char);
14516 int c_func (unsigned char i, unsigned char j)
14524 return asm_func(i,j);
14538 return c_func(10,9);
14543 The corresponding assembler function is:
14548 .globl _asm_func_PARM_2
14649 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14666 Note here that the return values
14667 \begin_inset LatexCommand \index{return value}
14671 are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
14673 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
14674 b' & 'acc' for four byte values.
14677 The parameter naming convention is _<function_name>_PARM_<n>, where n is
14678 the parameter number starting from 1, and counting from the left.
14679 The first parameter is passed in
14680 \begin_inset Quotes eld
14684 \begin_inset Quotes erd
14687 for a one byte parameter,
14688 \begin_inset Quotes eld
14692 \begin_inset Quotes erd
14696 \begin_inset Quotes eld
14700 \begin_inset Quotes erd
14703 for three bytes and
14704 \begin_inset Quotes eld
14708 \begin_inset Quotes erd
14711 for a four bytes parameter.
14712 The variable name for the second parameter will be _<function_name>_PARM_2.
14716 Assemble the assembler routine with the following command:
14723 asx8051 -losg asmfunc.asm
14730 Then compile and link the assembler routine to the C source file with the
14738 sdcc cfunc.c asmfunc.rel
14741 Assembler Routine (reentrant)
14745 \begin_inset LatexCommand \index{reentrant}
14750 \begin_inset LatexCommand \index{Assembler routines (reentrant)}
14754 the second parameter
14755 \begin_inset LatexCommand \index{function parameter}
14759 onwards will be passed on the stack, the parameters are pushed from right
14761 after the call the leftmost parameter will be on the top of the stack.
14762 Here is an example:
14767 extern int asm_func(unsigned char, unsigned char);
14771 int c_func (unsigned char i, unsigned char j) reentrant
14779 return asm_func(i,j);
14793 return c_func(10,9);
14798 The corresponding assembler routine is:
14897 \added_space_bottom bigskip
14898 The compiling and linking procedure remains the same, however note the extra
14899 entry & exit linkage required for the assembler code, _bp is the stack
14900 frame pointer and is used to compute the offset into the stack for parameters
14901 and local variables.
14905 \begin_inset LatexCommand \index{int (16 bit)}
14910 \begin_inset LatexCommand \index{long (32 bit)}
14917 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
14918 multiplication and modulus operations are implemented by support routines.
14919 These support routines are all developed in ANSI-C to facilitate porting
14920 to other MCUs, although some model specific assembler optimizations are
14922 The following files contain the described routines, all of them can be
14923 found in <installdir>/share/sdcc/lib.
14929 \begin_inset Tabular
14930 <lyxtabular version="3" rows="11" columns="2">
14932 <column alignment="left" valignment="top" leftline="true" width="0">
14933 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
14934 <row topline="true" bottomline="true">
14935 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14945 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14956 <row topline="true">
14957 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14965 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14970 16 bit multiplication
14974 <row topline="true">
14975 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14983 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14988 signed 16 bit division (calls _divuint)
14992 <row topline="true">
14993 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15001 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15006 unsigned 16 bit division
15010 <row topline="true">
15011 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15019 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15024 signed 16 bit modulus (calls _moduint)
15028 <row topline="true">
15029 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15037 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15042 unsigned 16 bit modulus
15046 <row topline="true">
15047 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15055 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15060 32 bit multiplication
15064 <row topline="true">
15065 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15073 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15078 signed 32 division (calls _divulong)
15082 <row topline="true">
15083 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15091 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15096 unsigned 32 division
15100 <row topline="true">
15101 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15109 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15114 signed 32 bit modulus (calls _modulong)
15118 <row topline="true" bottomline="true">
15119 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15127 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15132 unsigned 32 bit modulus
15145 Since they are compiled as
15150 \begin_inset LatexCommand \index{reentrant}
15155 \begin_inset LatexCommand \index{interrupt}
15159 service routines should not do any of the above operations.
15160 If this is unavoidable then the above routines will need to be compiled
15174 \begin_inset LatexCommand \index{-\/-stack-auto}
15180 option, after which the source program will have to be compiled with
15193 \begin_inset LatexCommand \index{-\/-int-long-reent}
15200 Notice that you don't have to call these routines directly.
15201 The compiler will use them automatically every time an integer operation
15205 Floating Point Support
15206 \begin_inset LatexCommand \index{Floating point support}
15213 SDCC supports IEEE (single precision 4 bytes) floating point numbers.
15214 The floating point support routines are derived from gcc's floatlib.c and
15215 consist of the following routines:
15223 \begin_inset Tabular
15224 <lyxtabular version="3" rows="17" columns="2">
15226 <column alignment="left" valignment="top" leftline="true" width="0">
15227 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
15228 <row topline="true" bottomline="true">
15229 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15246 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15255 <row topline="true">
15256 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15273 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15287 add floating point numbers
15291 <row topline="true">
15292 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15309 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15323 subtract floating point numbers
15327 <row topline="true">
15328 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15345 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15359 divide floating point numbers
15363 <row topline="true">
15364 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15381 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15395 multiply floating point numbers
15399 <row topline="true">
15400 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15417 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15431 convert floating point to unsigned char
15435 <row topline="true">
15436 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15453 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15467 convert floating point to signed char
15471 <row topline="true">
15472 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15489 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15503 convert floating point to unsigned int
15507 <row topline="true">
15508 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15525 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15539 convert floating point to signed int
15543 <row topline="true">
15544 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15570 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15584 convert floating point to unsigned long
15588 <row topline="true">
15589 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15606 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15620 convert floating point to signed long
15624 <row topline="true">
15625 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15642 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15656 convert unsigned char to floating point
15660 <row topline="true">
15661 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15678 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15692 convert char to floating point number
15696 <row topline="true">
15697 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15714 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15728 convert unsigned int to floating point
15732 <row topline="true">
15733 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15750 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15764 convert int to floating point numbers
15768 <row topline="true">
15769 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15786 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15800 convert unsigned long to floating point number
15804 <row topline="true" bottomline="true">
15805 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15822 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15836 convert long to floating point number
15848 \added_space_bottom bigskip
15849 These support routines are developed in ANSI-C so there is room for space
15850 and speed improvement
15856 These floating point routines (
15860 sinf(), cosf(), ...) for the mcs51 are implemented in assembler.
15865 Note if all these routines are used simultaneously the data space might
15867 For serious floating point usage the large model might be needed.
15868 Also notice that you don't have to call this routines directly.
15869 The compiler will use them automatically every time a floating point operation
15874 \begin_inset LatexCommand \index{Libraries}
15883 <pending: this is messy and incomplete - a little more information is in
15884 sdcc/doc/libdoc.txt
15889 Compiler support routines (_gptrget, _mulint etc.)
15892 Stdclib functions (puts, printf, strcat etc.)
15893 \layout Subsubsection
15899 \begin_inset LatexCommand \index{<stdio.h>}
15903 As usual on embedded systems you have to provide your own
15906 \begin_inset LatexCommand \index{getchar()}
15915 \begin_inset LatexCommand \index{putchar()}
15922 SDCC does not know whether the system connects to a serial line with or
15923 without handshake, LCD, keyboard or other device.
15937 You'll find examples for serial routines f.e.
15938 in sdcc/device/lib.
15944 \begin_inset LatexCommand \index{printf()}
15954 does not support float (except on ds390).
15955 To enable this recompile it with the option
15968 \begin_inset LatexCommand \index{USE\_FLOATS}
15974 on the command line.
15988 \begin_inset LatexCommand \index{-\/-model-large}
15994 for the mcs51 port, since this uses a lot of memory.
15997 If you're short on memory you might want to use
16000 \begin_inset LatexCommand \index{printf\_small()}
16015 For the mcs51 there additionally are assembly versions
16018 \begin_inset LatexCommand \index{printf\_tiny() (mcs51)}
16024 (subset of printf using less than 270 bytes) and
16027 \begin_inset LatexCommand \index{printf\_fast() (mcs51)}
16036 \begin_inset LatexCommand \index{printf\_fast\_f() (mcs51)}
16042 (floating-point aware version of printf_fast) which should fit the requirements
16043 of many embedded systems (printf_fast() can be customized by unsetting
16048 support long variables and field widths).
16049 \layout Subsubsection
16052 \begin_inset LatexCommand \index{malloc.h}
16059 As of SDCC 2.6.2 you no longer need to call an initialization routine before
16060 using dynamic memory allocation
16061 \begin_inset LatexCommand \index{dynamic memory allocation (malloc)}
16066 \begin_inset LatexCommand \index{heap (malloc)}
16070 space of 1024 bytes is provided for malloc to allocate memory from.
16073 If you need a different heap size you need to recompile _heap.c with the
16074 required size defined in HEAP_SIZE. It is recommended to make a copy of this
16075 file into your project directory and compile it there with:
16080 sdcc -c _heap.c -D HEAD_SIZE=2048
16083 And then link it with:
16087 sdcc main.rel _heap.rel
16092 Math functions (sinf, powf, sqrtf etc.)
16093 \layout Subsubsection
16098 See definitions in file <math.h>.
16105 \begin_inset LatexCommand \index{Libraries}
16109 included in SDCC should have a license at least as liberal as the GNU Lesser
16110 General Public License
16111 \begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
16122 license statements for the libraries are missing.
16123 sdcc/device/lib/ser_ir.c
16127 come with a GPL (as opposed to LGPL) License - this will not be liberal
16128 enough for many embedded programmers.
16131 If you have ported some library or want to share experience about some code
16133 falls into any of these categories Busses (I
16134 \begin_inset Formula $^{\textrm{2}}$
16137 C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
16138 cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
16139 Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list
16140 \begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}
16145 would certainly like to hear about it.
16147 \added_space_bottom bigskip
16148 Programmers coding for embedded systems are not especially famous for being
16149 enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
16150 e these references are very valuable.
16151 Let's help to create a climate where information is shared.
16157 MCS51 Memory Models
16158 \begin_inset LatexCommand \index{Memory model}
16163 \begin_inset LatexCommand \index{MCS51 memory model}
16168 \layout Subsubsection
16170 Small, Medium and Large
16173 SDCC allows three memory models for MCS51 code,
16182 Modules compiled with different memory models should
16186 be combined together or the results would be unpredictable.
16187 The library routines supplied with the compiler are compiled as small,
16189 The compiled library modules are contained in separate directories as small,
16190 medium and large so that you can link to the appropriate set.
16193 When the medium or large model is used all variables declared without a
16194 storage class will be allocated into the external ram, this includes all
16195 parameters and local variables (for non-reentrant
16196 \begin_inset LatexCommand \index{reentrant}
16201 When the small model is used variables without storage class are allocated
16202 in the internal ram.
16205 Judicious usage of the processor specific storage classes
16206 \begin_inset LatexCommand \index{Storage class}
16210 and the 'reentrant' function type will yield much more efficient code,
16211 than using the large model.
16212 Several optimizations are disabled when the program is compiled using the
16213 large model, it is therefore recommended that the small model be used unless
16214 absolutely required.
16215 \layout Subsubsection
16218 \begin_inset LatexCommand \label{sub:External-Stack}
16223 \begin_inset LatexCommand \index{stack}
16228 \begin_inset LatexCommand \index{External stack (mcs51)}
16235 The external stack (-
16246 \begin_inset LatexCommand \index{-\/-xstack}
16250 ) is located in pdata
16251 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
16255 memory (usually at the start of the external ram segment) and uses all
16256 unused space in pdata (max.
16268 -xstack option is used to compile the program, the parameters and local
16270 \begin_inset LatexCommand \index{local variables}
16274 of all reentrant functions are allocated in this area.
16275 This option is provided for programs with large stack space requirements.
16276 When used with the -
16287 \begin_inset LatexCommand \index{-\/-stack-auto}
16291 option, all parameters and local variables are allocated on the external
16292 stack (note: support libraries will need to be recompiled with the same
16294 There is a predefined target in the library makefile).
16297 The compiler outputs the higher order address byte of the external ram segment
16299 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
16304 \begin_inset LatexCommand \ref{sub:MCS51-variants}
16308 ), therefore when using the External Stack option, this port
16312 be used by the application program.
16316 \begin_inset LatexCommand \index{Memory model}
16321 \begin_inset LatexCommand \index{DS390 memory model}
16328 The only model supported is Flat 24
16329 \begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}
16334 This generates code for the 24 bit contiguous addressing mode of the Dallas
16336 In this mode, up to four meg of external RAM or code space can be directly
16338 See the data sheets at www.dalsemi.com for further information on this part.
16342 Note that the compiler does not generate any code to place the processor
16343 into 24 bitmode (although
16347 in the ds390 libraries will do that for you).
16353 \begin_inset LatexCommand \index{Tinibios (DS390)}
16357 , the boot loader or similar code must ensure that the processor is in 24
16358 bit contiguous addressing mode before calling the SDCC startup code.
16376 option, variables will by default be placed into the XDATA segment.
16381 Segments may be placed anywhere in the 4 meg address space using the usual
16393 Note that if any segments are located above 64K, the -r flag must be passed
16394 to the linker to generate the proper segment relocations, and the Intel
16395 HEX output format must be used.
16396 The -r flag can be passed to the linker by using the option
16400 on the SDCC command line.
16401 However, currently the linker can not handle code segments > 64k.
16405 \begin_inset LatexCommand \label{sec:Pragmas}
16410 \begin_inset LatexCommand \index{Pragmas}
16417 SDCC supports the following #pragma directives:
16425 \begin_inset LatexCommand \index{\#pragma save}
16429 - this will save most current options to the save/restore stack.
16430 See #pragma\SpecialChar ~
16439 \begin_inset LatexCommand \index{\#pragma restore}
16443 - will restore saved options from the last save.
16444 saves & restores can be nested.
16445 SDCC uses a save/restore stack: save pushes current options to the stack,
16446 restore pulls current options from the stack.
16447 See #pragma\SpecialChar ~
16458 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16463 \begin_inset LatexCommand \index{function prologue}
16467 function1[,function2[,function3...]] - The compiler by default uses a caller
16468 saves convention for register saving across function calls, however this
16469 can cause unnecessary register pushing & popping
16470 \begin_inset LatexCommand \index{push/pop}
16474 when calling small functions from larger functions.
16475 This option can be used to switch off the register saving convention for
16476 the function names specified.
16477 The compiler will not save registers when calling these functions, extra
16478 code need to be manually inserted at the entry & exit for these functions
16479 to save & restore the registers used by these functions, this can SUBSTANTIALLY
16480 reduce code & improve run time performance of the generated code.
16481 In the future the compiler (with inter procedural analysis) may be able
16482 to determine the appropriate scheme to use for each function call.
16493 -callee-saves command line option is used, the function names specified
16494 in #pragma\SpecialChar ~
16496 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16500 is appended to the list of functions specified in the command line.
16508 \begin_inset LatexCommand \index{\#pragma exclude}
16512 none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables the generation
16513 of pairs of push/pop
16514 \begin_inset LatexCommand \index{push/pop}
16523 \begin_inset LatexCommand \index{interrupt}
16536 The directive should be placed immediately before the ISR function definition
16537 and it affects ALL ISR functions following it.
16538 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
16539 exclude\SpecialChar ~
16541 \begin_inset LatexCommand \index{\#pragma exclude}
16546 See also the related keyword _naked
16547 \begin_inset LatexCommand \index{\_naked}
16552 \begin_inset LatexCommand \index{\_\_naked}
16564 \begin_inset LatexCommand \index{\#pragma less\_pedantic}
16568 - the compiler will not warn you anymore for obvious mistakes, you'r on
16577 \begin_inset LatexCommand \index{\#pragma disable\_warning}
16581 - the compiler will not warn you anymore about warning number <nnnn>.
16589 \begin_inset LatexCommand \index{\#pragma nogcse}
16593 - will stop global common subexpression elimination.
16601 \begin_inset LatexCommand \index{\#pragma noinduction}
16605 - will stop loop induction optimizations.
16613 \begin_inset LatexCommand \index{\#pragma noinvariant}
16617 - will not do loop invariant optimizations.
16618 For more details see Loop Invariants in section
16619 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
16631 \begin_inset LatexCommand \index{\#pragma noiv}
16635 - Do not generate interrupt
16636 \begin_inset LatexCommand \index{interrupt}
16641 \begin_inset LatexCommand \index{interrupt vector table}
16645 entries for all ISR functions defined after the pragma.
16646 This is useful in cases where the interrupt vector table must be defined
16647 manually, or when there is a secondary, manually defined interrupt vector
16649 for the autovector feature of the Cypress EZ-USB FX2).
16650 More elegantly this can be achieved by obmitting the optional interrupt
16651 number after the interrupt keyword, see section
16652 \begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}
16665 \begin_inset LatexCommand \index{\#pragma nojtbound}
16669 - will not generate code for boundary value checking, when switch statements
16670 are turned into jump-tables (dangerous).
16671 For more details see section
16672 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
16684 \begin_inset LatexCommand \index{\#pragma noloopreverse}
16688 - Will not do loop reversal optimization
16696 \begin_inset LatexCommand \index{\#pragma nooverlay}
16700 - the compiler will not overlay the parameters and local variables of a
16709 \begin_inset LatexCommand \index{\#pragma stackauto}
16724 \begin_inset LatexCommand \index{-\/-stack-auto}
16729 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
16733 Parameters and Local Variables.
16741 \begin_inset LatexCommand \index{\#pragma opt\_code\_speed}
16745 - The compiler will optimize code generation towards fast code, possibly
16746 at the expense of code size.
16747 Currently this has little effect.
16755 \begin_inset LatexCommand \index{\#pragma opt\_code\_size}
16759 - The compiler will optimize code generation towards compact code, possibly
16760 at the expense of code speed.
16761 Currently this has little effect.
16769 \begin_inset LatexCommand \index{\#pragma opt\_code\_balanced}
16773 - The compiler will attempt to generate code that is both compact and fast,
16774 as long as meeting one goal is not a detriment to the other (this is the
16784 \begin_inset LatexCommand \index{\#pragma std\_sdcc89}
16788 - Generally follow the C89 standard, but allow SDCC features that conflict
16789 with the standard (default).
16797 \begin_inset LatexCommand \index{\#pragma std\_c89}
16801 - Follow the C89 standard and disable SDCC features that conflict with the
16810 \begin_inset LatexCommand \index{\#pragma std\_sdcc99}
16814 - Generally follow the C99 standard, but allow SDCC features that conflict
16815 with the standard (incomplete support).
16823 \begin_inset LatexCommand \index{\#pragma std\_c99}
16827 - Follow the C99 standard and disable SDCC features that conflict with the
16828 standard (incomplete support).
16836 \begin_inset LatexCommand \index{\#pragma codeseg}
16840 - Use this name (max.
16841 8 characters) for the code segment.
16860 \begin_inset LatexCommand \index{\#pragma constseg}
16864 - Use this name (max.
16865 8 characters) for the const segment.
16879 The preprocessor SDCPP
16880 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
16884 supports the following #pragma directives:
16892 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
16896 (+ | -) - switch _asm _endasm block preprocessing on / off.
16898 You use this prama to define multilines of assembly code.
16899 This will prevent the preprocessor from changing the formating required
16901 Below is an example on how to use this pragma.
16906 #pragma preproc_asm -
16907 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
16913 #define MYDELAY _asm
16918 nop ;my assembly comment...
16932 #pragma preproc_asm +
16962 The pragma's are intended to be used to turn-on or off certain optimizations
16963 which might cause the compiler to generate extra stack / data space to
16964 store compiler generated temporary variables.
16965 This usually happens in large functions.
16966 Pragma directives should be used as shown in the following example, they
16967 are used to control options & optimizations for a given function; pragmas
16968 should be placed before and/or after a function, placing pragma's inside
16969 a function body could have unpredictable results.
16975 \begin_inset LatexCommand \index{\#pragma save}
16986 /* save the current settings */
16989 \begin_inset LatexCommand \index{\#pragma nogcse}
16998 /* turnoff global subexpression elimination */
17000 #pragma noinduction
17001 \begin_inset LatexCommand \index{\#pragma noinduction}
17005 /* turn off induction optimizations */
17028 \begin_inset LatexCommand \index{\#pragma restore}
17032 /* turn the optimizations back on */
17035 The compiler will generate a warning message when extra space is allocated.
17036 It is strongly recommended that the save and restore pragma's be used when
17037 changing options for a function.
17046 Defines Created by the Compiler
17049 The compiler creates the following #defines
17050 \begin_inset LatexCommand \index{\#defines}
17055 \begin_inset LatexCommand \index{Defines created by the compiler}
17065 \begin_inset Tabular
17066 <lyxtabular version="3" rows="11" columns="2">
17068 <column alignment="left" valignment="top" leftline="true" width="3in">
17069 <column alignment="left" valignment="top" leftline="true" rightline="true" width="3in">
17070 <row topline="true" bottomline="true">
17071 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17081 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17092 <row topline="true">
17093 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17099 \begin_inset LatexCommand \index{SDCC}
17106 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17112 Since version 2.5.6 the version number as an int (ex.
17117 <row topline="true">
17118 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17124 \begin_inset LatexCommand \index{SDCC\_mcs51}
17129 \begin_inset LatexCommand \index{SDCC\_ds390}
17134 \begin_inset LatexCommand \index{SDCC\_z80}
17141 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17146 depending on the model used (e.g.: -mds390)
17150 <row topline="true">
17151 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17157 \begin_inset LatexCommand \index{\_\_mcs51}
17162 \begin_inset LatexCommand \index{\_\_ds390}
17167 \begin_inset LatexCommand \index{\_\_hc08}
17172 \begin_inset LatexCommand \index{\_\_z80}
17179 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17184 depending on the model used (e.g.
17189 <row topline="true">
17190 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17196 \begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
17203 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17226 <row topline="true">
17227 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17233 \begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
17240 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17263 <row topline="true">
17264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17270 \begin_inset LatexCommand \index{SDCC\_MODEL\_MEDIUM}
17277 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17300 <row topline="true">
17301 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17307 \begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
17314 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17337 <row topline="true">
17338 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17344 \begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
17351 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17374 <row topline="true">
17375 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17381 \begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
17388 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17401 <row topline="true" bottomline="true">
17402 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17408 \begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
17415 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17435 Notes on supported Processors
17439 \begin_inset LatexCommand \label{sub:MCS51-variants}
17444 \begin_inset LatexCommand \index{MCS51 variants}
17451 MCS51 processors are available from many vendors and come in many different
17453 While they might differ considerably in respect to Special Function Registers
17454 the core MCS51 is usually not modified or is kept compatible.
17458 pdata access by SFR
17461 With the upcome of devices with internal xdata and flash memory devices
17463 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
17467 as dedicated I/O port is becoming more popular.
17468 Switching the high byte for pdata
17469 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
17473 access which was formerly done by port P2 is then achieved by a Special
17475 \begin_inset LatexCommand \index{sfr}
17480 In well-established MCS51 tradition the address of this
17484 is where the chip designers decided to put it.
17485 Needless to say that they didn't agree on a common name either.
17486 So that the startup code can correctly initialize xdata variables, you
17487 should define an sfr with the name _XPAGE
17490 \begin_inset LatexCommand \index{\_XPAGE (mcs51)}
17496 at the appropriate location if the default, port P2, is not used for this.
17502 __sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family */
17507 __sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17512 __sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17515 For more exotic implementations further customizations may be needed.
17517 \begin_inset LatexCommand \ref{sub:Startup-Code}
17521 for other possibilities.
17524 Other Features available by SFR
17526 \added_space_bottom bigskip
17527 Some MCS51 variants offer features like Double DPTR
17528 \begin_inset LatexCommand \index{DPTR}
17532 , multiple DPTR, decrementing DPTR, 16x16 Multiply.
17533 These are currently not used for the MCS51 port.
17534 If you absolutely need them you can fall back to inline assembly or submit
17540 \added_space_bottom bigskip
17542 \begin_inset LatexCommand \index{DS80C400}
17547 \begin_inset LatexCommand \index{DS400}
17551 microcontroller has a rich set of peripherals.
17552 In its built-in ROM library it includes functions to access some of the
17553 features, among them is a TCP stack with IP4 and IP6 support.
17554 Library headers (currently in beta status) and other files are provided
17558 \begin_inset LatexCommand \url{ftp://ftp.dalsemi.com/pub/tini/ds80c400/c_libraries/sdcc/index.html}
17566 The Z80 and gbz80 port
17569 SDCC can target both the Zilog Z80
17570 \begin_inset LatexCommand \index{Z80}
17574 and the Nintendo Gameboy's Z80-like gbz80
17575 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
17580 The Z80 port is passed through the same
17583 \begin_inset LatexCommand \index{Regression test}
17590 \begin_inset LatexCommand \ref{sec:Quality-control}
17594 ) as the MCS51 and DS390 ports, so floating point support, support for long
17595 variables and bitfield support is fine.
17596 See mailing lists and forums about interrupt routines.
17598 \added_space_bottom bigskip
17599 As always, the code is the authoritative reference - see z80/ralloc.c and
17602 \begin_inset LatexCommand \index{Z80!stack}
17606 frame is similar to that generated by the IAR Z80 compiler.
17607 IX is used as the base pointer, HL and IY are used as a temporary registers,
17608 and BC and DE are available for holding variables.
17610 \begin_inset LatexCommand \index{Z80!return value}
17614 for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
17616 The gbz80 port use the same set of registers for the return values, but
17617 in a different order of significance: E (one byte), DE (two bytes), or
17624 The port to the Freescale/Motorola HC08
17625 \begin_inset LatexCommand \index{HC08}
17629 family has been added in October 2003, and is still undergoing some basic
17631 The code generator is complete, but the register allocation is still quite
17633 Some of the SDCC's standard C library functions have embedded non-HC08
17634 inline assembly and so are not yet usable.
17636 \added_space_bottom bigskip
17637 The HC08 port passes the regression test suite (see section
17638 \begin_inset LatexCommand \ref{sec:Quality-control}
17649 \begin_inset LatexCommand \index{PIC14}
17653 port still requires a major effort from the development community.
17654 However it can work for simple code.
17655 It passes its (smaller set of) regression tests
17656 \begin_inset LatexCommand \index{Regression test (PIC14)}
17662 sdcc/src/regression
17667 C code and 14bit PIC code page
17668 \begin_inset LatexCommand \index{code page (pic14)}
17673 \begin_inset LatexCommand \index{RAM bank (pic14)}
17680 The linker organizes allocation for the code page and RAM banks.
17681 It does not have intimate knowledge of the code flow.
17682 It will put all the code section of a single asm file into a single code
17684 In order to make use of multiple code pages, separate asm files must be
17686 The compiler treats all functions of a single C file as being in the same
17687 code page unless it is non static.
17688 The compiler treats all local variables of a single C file as being in
17689 the same RAM bank unless it is an extern.
17693 To get the best follow these guide lines:
17696 make local functions static, as non static functions require code page selection
17700 Make local variables static as extern variables require RAM bank selection
17704 For devices that have multiple code pages it is more efficient to use the
17705 same number of files as pages, i.e.
17706 for the 16F877 use 4 separate files and i.e.
17707 for the 16F874 use 2 separate files.
17708 This way the linker can put the code for each file into different code
17709 pages and the compiler can allocate reusable variables more efficiently
17710 and there's less page selection overhead.
17711 And as for any 8 bit micro (especially for PIC 14 as they have a very simple
17712 instruction set) use 'unsigned char' whereever possible instead of 'int'.
17715 Creating a device include file
17718 For generating a device include file
17719 \begin_inset LatexCommand \index{PIC14!Header files}
17723 use the support perl script inc2h.pl kept in directory support/script.
17729 For the interrupt function, use the keyword 'interrupt'
17730 \begin_inset LatexCommand \index{PIC14!interrupt}
17734 with level number of 0 (PIC14 only has 1 interrupt so this number is only
17735 there to avoid a syntax error - it ought to be fixed).
17741 void Intr(void) interrupt 0
17747 T0IF = 0; /* Clear timer interrupt */
17752 Linking and assembling
17755 For assembling you can use either GPUTILS'
17756 \begin_inset LatexCommand \index{gputils (pic tools)}
17760 gpasm.exe or MPLAB's mpasmwin.exe.
17761 GPUTILS is available from
17762 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
17767 For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
17768 If you use MPLAB and an interrupt function then the linker script file
17769 vectors section will need to be enlarged to link with mplink.
17792 sdcc -S -V -mpic14 -p16F877 $<
17806 $(PRJ).hex: $(OBJS)
17816 gplink -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS) libsdcc.lib
17838 sdcc -S -V -mpic14 -p16F877 $<
17848 mpasmwin /q /o $*.asm
17852 $(PRJ).hex: $(OBJS)
17862 mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS) libsdcc.lib
17865 Please note that indentations within a
17869 have to be done with a tabulator character.
17872 Command-line options
17875 Besides the switches common to all SDCC backends, the PIC14 port accepts
17876 the following options (for an updated list see sdcc -
17888 \labelwidthstring 00.00.0000
17901 \begin_inset LatexCommand \index{PIC14!Options!-\/-debug-extra}
17905 emit debug info in assembly output
17907 \labelwidthstring 00.00.0000
17920 \begin_inset LatexCommand \index{PIC14!Options!-\/-no-pcode-opt}
17924 disable (slightly faulty) optimization on pCode
17928 \layout Subsubsection
17930 error: missing definition for symbol
17931 \begin_inset Quotes sld
17935 \begin_inset Quotes srd
17941 The PIC14 port uses library routines to provide more complex operations
17942 like multiplication, division/modulus and (generic) pointer dereferencing.
17943 In order to add these routines to your project, you must link with PIC14's
17949 For single source file projects this is done automatically, more complex
17954 to the linker's arguments.
17955 Make sure you also add an include path for the library (using the -I switch
17957 \layout Subsubsection
17959 Processor mismatch in file
17960 \begin_inset Quotes sld
17964 \begin_inset Quotes srd
17970 This warning can usually be ignored due to the very good compatibility amongst
17972 \begin_inset LatexCommand \index{PIC14}
17979 You might also consider recompiling the library for your specific device
17980 by changing the ARCH=p16f877 (default target) entry in
17982 device/lib/pic/Makefile.in
17986 device/lib/pic/Makefile
17988 to reflect your device.
17989 This might even improve performance for smaller devices as unneccesary
17990 BANKSELs migth be removed.
17994 \layout Subsubsection
17999 Currently, data can only be initialized if it resides in the source file
18005 Data in other source files will silently
18013 \begin_inset Marginal
18028 \begin_inset LatexCommand \index{PIC16}
18036 \begin_inset LatexCommand \index{PIC16}
18040 port is the portion of SDCC that is responsible to produce code for the
18042 \begin_inset LatexCommand \index{Microchip}
18046 (TM) microcontrollers with 16 bit core.
18047 Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
18048 Currently supported devices are:
18052 \begin_inset Tabular
18053 <lyxtabular version="3" rows="4" columns="6">
18055 <column alignment="center" valignment="top" leftline="true" width="0">
18056 <column alignment="center" valignment="top" leftline="true" width="0">
18057 <column alignment="center" valignment="top" leftline="true" width="0">
18058 <column alignment="center" valignment="top" leftline="true" width="0">
18059 <column alignment="center" valignment="top" leftline="true" width="0">
18060 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18061 <row topline="true">
18062 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18070 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18078 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18086 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18094 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18102 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18111 <row topline="true">
18112 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18120 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18128 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18136 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18144 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18152 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18161 <row topline="true">
18162 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18170 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18178 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18186 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18194 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18202 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18211 <row topline="true" bottomline="true">
18212 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18220 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18228 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18236 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18243 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18250 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18268 PIC16 port supports the standard command line arguments as supposed, with
18269 the exception of certain cases that will be mentioned in the following
18272 \labelwidthstring 00.00.0000
18285 \begin_inset LatexCommand \index{PIC16!Options!-\/-callee-saves}
18301 \labelwidthstring 00.00.0000
18314 \begin_inset LatexCommand \index{PIC16!Options!-\/-all-callee-saves}
18318 All function arguments are passed on stack by default.
18321 There is no need to specify this in the command line.
18323 \labelwidthstring 00.00.0000
18335 -fommit-frame-pointer
18336 \begin_inset LatexCommand \index{PIC16!Options!-\/-fommit-frame-pointer}
18340 Frame pointer will be omitted when the function uses no local variables.
18343 Port Specific Options
18344 \begin_inset LatexCommand \index{Options PIC16}
18351 The port specific options appear after the global options in the sdcc --help
18353 \layout Subsubsection
18358 General options enable certain port features and optimizations.
18360 \labelwidthstring 00.00.0000
18372 -stack-model=[model] Used in conjuction with the command above.
18373 Defines the stack model to be used, valid stack models are :
18376 \labelwidthstring 00.00.0000
18382 Selects small stack model.
18383 8 bit stack and frame pointers.
18384 Supports 256 bytes stack size.
18386 \labelwidthstring 00.00.0000
18392 Selects large stack model.
18393 16 bit stack and frame pointers.
18394 Supports 65536 bytes stack size.
18397 \labelwidthstring 00.00.0000
18409 -preplace-udata-with=[kword] Replaces the default udata keyword for allocating
18410 unitialized data variables with [kword].
18411 Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
18413 \labelwidthstring 00.00.0000
18425 -ivt-loc <nnnn> positions the Interrupt Vector Table at location <nnnn>.
18426 Useful for bootloaders.
18428 \labelwidthstring 00.00.0000
18440 -asm= sets the full path and name of an external assembler to call.
18442 \labelwidthstring 00.00.0000
18454 -link= sets the full path and name of an external linker to call.
18456 \labelwidthstring 00.00.0000
18469 \begin_inset LatexCommand \index{PIC16!MPLAB}
18473 compatibility option.
18474 Currently only suppresses special gpasm directives.
18475 \layout Subsubsection
18477 Optimization Options
18479 \labelwidthstring 00.00.0000
18491 -optimize-goto Try to use (conditional) BRA instead of GOTO
18493 \labelwidthstring 00.00.0000
18505 -optimize-cmp Try to optimize some compares.
18507 \labelwidthstring 00.00.0000
18519 -optimize-df Analyze the dataflow of the generated code and improve it.
18521 \labelwidthstring 00.00.0000
18533 -obanksel=nn Set optimization level for inserting BANKSELs.
18538 \labelwidthstring 00.00.0000
18542 \labelwidthstring 00.00.0000
18544 1 checks previous used register and if it is the same then does not emit
18545 BANKSEL, accounts only for labels.
18547 \labelwidthstring 00.00.0000
18549 2 tries to check the location of (even different) symbols and removes BANKSELs
18550 if they are in the same bank.
18555 Important: There might be problems if the linker script has data sections
18556 across bank borders!
18558 \layout Subsubsection
18562 \labelwidthstring 00.00.0000
18574 -nodefaultlibs do not link default libraries when linking
18576 \labelwidthstring 00.00.0000
18588 -no-crt Don't link the default run-time modules
18590 \labelwidthstring 00.00.0000
18602 -use-crt= Use a custom run-time module instead of the defaults.
18603 \layout Subsubsection
18608 Debugging options enable extra debugging information in the output files.
18610 \labelwidthstring 00.00.0000
18622 -debug-xtra Similar to -
18633 \begin_inset LatexCommand \index{-\/-debug}
18637 , but dumps more information.
18639 \labelwidthstring 00.00.0000
18651 -debug-ralloc Force register allocator to dump <source>.d file with debugging
18653 <source> is the name of the file compiled.
18655 \labelwidthstring 00.00.0000
18667 -pcode-verbose Enable pcode debugging information in translation.
18669 \labelwidthstring 00.00.0000
18681 -denable-peeps Force the usage of peepholes.
18684 \labelwidthstring 00.00.0000
18696 -gstack Trace push/pops for stack pointer overflow
18698 \labelwidthstring 00.00.0000
18710 -call-tree dump call tree in .calltree file
18713 Enviromental Variables
18716 There is a number of enviromental variables that can be used when running
18717 SDCC to enable certain optimizations or force a specific program behaviour.
18718 these variables are primarily for debugging purposes so they can be enabled/dis
18722 Currently there is only two such variables available:
18724 \labelwidthstring 00.00.0000
18726 OPTIMIZE_BITFIELD_POINTER_GET when this variable exists reading of structure
18727 bitfields is optimized by directly loading FSR0 with the address of the
18728 bitfield structure.
18729 Normally SDCC will cast the bitfield structure to a bitfield pointer and
18731 This step saves data ram and code space for functions that perform heavy
18734 80 bytes of code space are saved when compiling malloc.c with this option).
18737 \labelwidthstring 00.00.0000
18739 NO_REG_OPT do not perform pCode registers optimization.
18740 This should be used for debugging purposes.
18741 In some where bugs in the pcode optimizer are found, users can benefit
18742 from temporarily disabling the optimizer until the bug is fixed.
18745 Preprocessor Macros
18749 \begin_inset LatexCommand \index{PIC16}
18753 port defines the following preprocessor macros while translating a source.
18757 \begin_inset Tabular
18758 <lyxtabular version="3" rows="6" columns="2">
18760 <column alignment="center" valignment="top" leftline="true" width="0">
18761 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18762 <row topline="true" bottomline="true">
18763 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18771 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18780 <row topline="true">
18781 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18789 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18794 Port identification
18798 <row topline="true">
18799 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18817 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18822 Port identification (same as above)
18826 <row topline="true">
18827 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18835 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18840 MCU Identification.
18845 is the microcontrol identification number, i.e.
18850 <row topline="true">
18851 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18869 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18874 MCU Identification (same as above)
18878 <row topline="true" bottomline="true">
18879 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18887 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18892 nnn = SMALL or LARGE respectively according to the stack model used
18903 In addition the following macros are defined when calling assembler:
18907 \begin_inset Tabular
18908 <lyxtabular version="3" rows="4" columns="2">
18910 <column alignment="center" valignment="top" leftline="true" width="0">
18911 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18912 <row topline="true" bottomline="true">
18913 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18921 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18930 <row topline="true">
18931 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18939 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18944 MCU Identification.
18949 is the microcontrol identification number, i.e.
18954 <row topline="true">
18955 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18963 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18968 nnn = SMALL or LARGE respectively according to the memory model used for
18973 <row topline="true" bottomline="true">
18974 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18982 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18987 nnn = SMALL or LARGE respectively according to the stack model used
19002 \begin_inset LatexCommand \index{PIC16}
19006 port uses the following directories for searching header files and libraries.
19010 \begin_inset Tabular
19011 <lyxtabular version="3" rows="3" columns="4">
19013 <column alignment="center" valignment="top" leftline="true" width="0">
19014 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19015 <column alignment="center" valignment="top" width="0">
19016 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19017 <row topline="true" bottomline="true">
19018 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19026 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19034 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19042 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19051 <row topline="true">
19052 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19057 PREFIX/sdcc/include/pic16
19060 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19065 PIC16 specific headers
19068 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19076 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19085 <row topline="true" bottomline="true">
19086 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19091 PREFIX/sdcc/lib/pic16
19094 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19099 PIC16 specific libraries
19102 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19110 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19127 \begin_inset LatexCommand \label{sub:PIC16_Pragmas}
19135 \begin_inset LatexCommand \index{PIC16}
19139 port currently supports the following pragmas:
19141 \labelwidthstring 00.00.0000
19144 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}
19149 \begin_inset LatexCommand \index{PIC16!stack}
19153 forces the code generator to initialize the stack & frame pointers at a
19155 This is an adhoc solution for cases where no STACK directive is available
19156 in the linker script or gplink is not instructed to create a stack section.
19158 The stack pragma should be used only once in a project.
19159 Multiple pragmas may result in indeterminate behaviour of the program.
19165 The old format (ie.
19166 #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
19167 cross page boundaries (or even exceed the available data RAM) and crash
19169 Make sure that stack does not cross page boundaries when using the SMALL
19175 The format is as follows:
19178 #pragma stack bottom_address [stack_size]
19185 is the lower bound of the stack section.
19186 The stack pointer initially will point at address (bottom_address+stack_size-1).
19194 /* initializes stack of 100 bytes at RAM address 0x200 */
19197 #pragma stack 0x200 100
19200 If the stack_size field is omitted then a stack is created with the default
19202 This size might be enough for most programs, but its not enough for operations
19203 with deep function nesting or excessive stack usage.
19205 \labelwidthstring 00.00.0000
19209 This pragma is deprecated.
19210 Its use will cause a warning message to be issued.
19216 \labelwidthstring 00.00.0000
19219 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}
19223 place a function symbol at static FLASH address
19231 /* place function test_func at 0x4000 */
19234 #pragma code test_func 0x4000
19238 \labelwidthstring 00.00.0000
19240 library instructs the linker to use a library module.
19245 #pragma library module_name
19252 can be any library or object file (including its path).
19253 Note that there are four reserved keywords which have special meaning.
19258 \begin_inset Tabular
19259 <lyxtabular version="3" rows="6" columns="3">
19261 <column alignment="center" valignment="top" leftline="true" width="0">
19262 <column alignment="block" valignment="top" leftline="true" width="20page%">
19263 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
19264 <row topline="true" bottomline="true">
19265 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19273 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19281 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19290 <row topline="true">
19291 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19301 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19306 ignore all library pragmas
19309 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19320 <row topline="true">
19321 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19331 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19339 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19352 <row topline="true">
19353 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19363 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19368 link the Math libarary
19371 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19384 <row topline="true">
19385 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19395 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19400 link the I/O library
19403 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19416 <row topline="true" bottomline="true">
19417 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19427 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19432 link the debug library
19435 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19454 * is the device number, i.e.
19455 452 for PIC18F452 MCU.
19458 This feature allows for linking with specific libraries withoug having to
19459 explicit name them in the command line.
19464 keyword will reject all modules specified by the library pragma.
19466 \labelwidthstring 00.00.0000
19468 udata pragma udata instructs the compiler to emit code so that linker will
19469 place a variable at a specific memory bank
19477 /* places variable foo at bank2 */
19480 #pragma udata bank2 foo
19486 In order for this pragma to work extra SECTION directives should be added
19487 in the .lkr script.
19488 In the following example a sample .lkr file is shown:
19493 // Sample linker script for the PIC18F452 processor
19499 CODEPAGE NAME=vectors START=0x0 END=0x29 PROTECTED
19502 CODEPAGE NAME=page START=0x2A END=0x7FFF
19505 CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
19508 CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
19511 CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
19514 CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED
19517 ACCESSBANK NAME=accessram START=0x0 END=0x7F
19522 DATABANK NAME=gpr0 START=0x80 END=0xFF
19525 DATABANK NAME=gpr1 START=0x100 END=0x1FF
19528 DATABANK NAME=gpr2 START=0x200 END=0x2FF
19531 DATABANK NAME=gpr3 START=0x300 END=0x3FF
19534 DATABANK NAME=gpr4 START=0x400 END=0x4FF
19537 DATABANK NAME=gpr5 START=0x500 END=0x5FF
19540 ACCESSBANK NAME=accesssfr START=0xF80 END=0xFFF PROTECTED
19545 SECTION NAME=CONFIG ROM=config
19550 SECTION NAME=bank0 RAM=gpr0 # these SECTION directives
19553 SECTION NAME=bank1 RAM=gpr1 # should be added to link
19556 SECTION NAME=bank2 RAM=gpr2 # section name 'bank?' with
19559 SECTION NAME=bank3 RAM=gpr3 # a specific DATABANK name
19562 SECTION NAME=bank4 RAM=gpr4
19565 SECTION NAME=bank5 RAM=gpr5
19568 The linker will recognise the section name set in the pragma statement and
19569 will position the variable at the memory bank set with the RAM field at
19570 the SECTION line in the linker script file.
19574 \begin_inset LatexCommand \label{sub:PIC16_Header-Files}
19581 There is one main header file
19582 \begin_inset LatexCommand \index{PIC16!Header files}
19586 that can be included to the source files using the pic16
19587 \begin_inset LatexCommand \index{PIC16}
19597 This header file contains the definitions for the processor special registers,
19598 so it is necessary if the source accesses them.
19599 It can be included by adding the following line in the beginning of the
19603 #include <pic18fregs.h>
19606 The specific microcontroller is selected within the pic18fregs.h automatically,
19607 so the same source can be used with a variety of devices.
19614 \begin_inset LatexCommand \index{PIC16!Libraries}
19619 \begin_inset LatexCommand \index{PIC16}
19623 port depends on are the microcontroller device libraries which contain
19624 the symbol definitions for the microcontroller special function registers.
19625 These libraries have the format pic18fxxxx.lib, where
19629 is the microcontroller identification number.
19630 The specific library is selected automatically by the compiler at link
19631 stage according to the selected device.
19634 Libraries are created with gplib which is part of the gputils package
19635 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
19640 \layout Subsubsection*
19642 Building the libraries
19645 Before using SDCC/pic16 there are some libraries that need to be compiled.
19646 This process is not done automatically by SDCC since not all users use
19647 SDCC for pic16 projects.
19648 So each user should compile the libraries separately.
19651 The steps to compile the pic16 libraries under Linux are:
19654 cd device/lib/pic16
19669 su -c 'make install' # install the libraries, you need the root password
19672 If you need to install the headers too, do:
19678 su -c 'make install' # install the headers, you need the root password
19681 There exist a special target to build the I/O libraries.
19682 This target is not automatically build because it will build the I/O library
19688 This way building will take quite a lot of time.
19689 Users are advised to edit the
19691 device/lib/pic16/pics.build
19693 file and then execute:
19702 The following memory models are supported by the PIC16 port:
19711 Memory model affects the default size of pointers within the source.
19712 The sizes are shown in the next table:
19716 \begin_inset Tabular
19717 <lyxtabular version="3" rows="3" columns="3">
19719 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19720 <column alignment="center" valignment="top" leftline="true" width="0">
19721 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19722 <row topline="true" bottomline="true">
19723 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19728 Pointer sizes according to memory model
19731 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19739 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19748 <row topline="true" bottomline="true">
19749 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19757 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19765 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19774 <row topline="true" bottomline="true">
19775 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19783 <cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
19791 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19807 It is advisable that all sources within a project are compiled with the
19809 If one wants to override the default memory model, this can be done by
19810 declaring a pointer as
19819 Far selects large memory model's pointers, while near selects small memory
19823 The standard device libraries (see
19824 \begin_inset LatexCommand \ref{sub:PIC16_Header-Files}
19828 ) contain no reference to pointers, so they can be used with both memory
19836 \begin_inset LatexCommand \index{PIC16!stack}
19840 implementation for the PIC16 port uses two indirect registers, FSR1 and
19843 \labelwidthstring 00.00.0000
19845 FSR1 is assigned as stack pointer
19847 \labelwidthstring 00.00.0000
19849 FSR2 is assigned as frame pointer
19852 The following stack models are supported by the PIC16 port
19873 model means that only the FSRxL byte is used to access stack and frame,
19880 uses both FSRxL and FSRxH registers.
19881 The following table shows the stack/frame pointers sizes according to stack
19882 model and the maximum space they can address:
19886 \begin_inset Tabular
19887 <lyxtabular version="3" rows="3" columns="3">
19889 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19890 <column alignment="center" valignment="top" leftline="true" width="0">
19891 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19892 <row topline="true" bottomline="true">
19893 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19898 Stack & Frame pointer sizes according to stack model
19901 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19909 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19918 <row topline="true">
19919 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19927 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19935 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19944 <row topline="true" bottomline="true">
19945 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19953 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19961 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19981 stack model is currently not working properly throughout the code generator.
19982 So its use is not advised.
19983 Also there are some other points that need special care:
19988 Do not create stack sections with size more than one physical bank (that
19992 Stack sections should no cross physical bank limits (i.e.
19993 #pragma stack 0x50 0x100)
19996 These limitations are caused by the fact that only FSRxL is modified when
19997 using SMALL stack model, so no more than 256 bytes of stack can be used.
19998 This problem will disappear after LARGE model is fully implemented.
20004 In addition to the standard SDCC function keywords, PIC16
20005 \begin_inset LatexCommand \index{PIC16}
20009 port makes available two more:
20011 \labelwidthstring 00.00.0000
20014 \begin_inset LatexCommand \index{PIC16!wparam}
20018 Use the WREG to pass one byte of the first function argument.
20019 This improves speed but you may not use this for functions with arguments
20020 that are called via function pointers, otherwise the first byte of the
20021 first parameter will get lost.
20025 void func_wparam(int a) wparam
20031 /* WREG hold the lower part of a */
20034 /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
20044 This keyword replaces the deprecated wparam pragma.
20046 \labelwidthstring 00.00.0000
20049 \begin_inset LatexCommand \index{PIC16!shadowregs}
20053 When entering/exiting an ISR, it is possible to take advantage of the PIC18F
20054 hardware shadow registers which hold the values of WREG, STATUS and BSR
20056 This can be done by adding the keyword
20064 keyword in the function's header.
20067 void isr_shadow(void) shadowregs interrupt 1
20083 instructs the code generator not to store/restore WREG, STATUS, BSR when
20084 entering/exiting the ISR.
20087 Function return values
20090 Return values from functions are placed to the appropriate registers following
20091 a modified Microchip policy optimized for SDCC.
20092 The following table shows these registers:
20096 \begin_inset Tabular
20097 <lyxtabular version="3" rows="6" columns="2">
20099 <column alignment="center" valignment="top" leftline="true" width="0">
20100 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20101 <row topline="true" bottomline="true">
20102 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20110 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20115 destination register
20119 <row topline="true">
20120 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20128 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20137 <row topline="true">
20138 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20146 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20155 <row topline="true">
20156 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20164 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20173 <row topline="true">
20174 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20182 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20187 FSR0L:PRODH:PRODL:WREG
20191 <row topline="true" bottomline="true">
20192 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20200 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20205 on stack, FSR0 points to the beginning
20220 \begin_inset LatexCommand \index{PIC16!interrupt}
20224 service routine (ISR) is declared using the
20231 void isr(void) interrupt
20249 is the interrupt number, which for PIC18F devices can be:
20253 \begin_inset Tabular
20254 <lyxtabular version="3" rows="4" columns="3">
20256 <column alignment="center" valignment="top" leftline="true" width="0">
20257 <column alignment="center" valignment="top" leftline="true" width="0">
20258 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20259 <row topline="true" bottomline="true">
20260 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20270 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20278 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20283 Interrupt Vector Address
20287 <row topline="true">
20288 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20296 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20304 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20313 <row topline="true">
20314 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20331 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20345 HIGH priority interrupts
20348 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20357 <row topline="true" bottomline="true">
20358 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20366 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20371 LOW priority interrupts
20374 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20390 When generating assembly code for ISR the code generator places a
20396 Interrupt Vector Address
20398 which points at the genetated ISR.
20399 This single GOTO instruction is part of an automatically generated
20401 interrupt entry point
20404 The actuall ISR code is placed as normally would in the code space.
20405 Upon interrupt request, the GOTO instruction is executed which jumps to
20407 When declaring interrupt functions as _naked this GOTO instruction is
20412 The whole interrupt functions is therefore placed at the Interrupt Vector
20413 Address of the specific interrupt.
20414 This is not a problem for the LOW priority interrupts, but it is a problem
20415 for the RESET and the HIGH priority interrupts because code may be written
20416 at the next interrupt´s vector address and cause undeterminate program
20417 behaviour if that interrupt is raised.
20423 This is not a problem when
20426 this is a HIGH interrupt ISR and LOW interrupts are
20433 when the ISR is small enough not to reach the next interrupt´s vector address.
20443 is possible to be omitted.
20444 This way a function is generated similar to an ISR, but it is not assigned
20448 When entering an interrupt, currently the PIC16
20449 \begin_inset LatexCommand \index{PIC16}
20453 port automatically saves the following registers:
20465 PROD (PRODL and PRODH)
20468 FSR0 (FSR0L and FSR0H)
20471 These registers are restored upon return from the interrupt routine.
20477 NOTE that when the _naked attribute is specified for an interrupt routine,
20478 then NO registers are stored or restored.
20487 Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
20488 There are 3 types of generic pointers currently implemented data, code
20489 and eeprom pointers.
20490 They are differentiated by the value of the 7th and 6th bits of the upper
20495 \begin_inset Tabular
20496 <lyxtabular version="3" rows="5" columns="5">
20498 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20499 <column alignment="center" valignment="top" width="0">
20500 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20501 <column alignment="center" valignment="top" width="0">
20502 <column alignment="left" valignment="top" rightline="true" width="0">
20503 <row topline="true" bottomline="true">
20504 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20512 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20520 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20528 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20533 rest of the pointer
20536 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20545 <row topline="true" bottomline="true">
20546 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20554 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20562 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20570 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20579 uuuuuu uuuuxxxx xxxxxxxx
20582 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20587 a 12-bit data pointer in data RAM memory
20591 <row bottomline="true">
20592 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20600 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20608 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20616 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20625 uxxxxx xxxxxxxx xxxxxxxx
20628 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20633 a 21-bit code pointer in FLASH memory
20637 <row bottomline="true">
20638 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20646 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20654 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20662 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20671 uuuuuu uuuuuuxx xxxxxxxx
20674 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20679 a 10-bit eeprom pointer in EEPROM memory
20683 <row bottomline="true">
20684 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20692 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20700 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20708 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20717 xxxxxx xxxxxxxx xxxxxxxx
20720 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20725 unimplemented pointer type
20736 Generic pointer are read and written with a set of library functions which
20737 read/write 1, 2, 3, 4 bytes.
20741 \layout Subsubsection
20743 Standard I/O Streams
20750 the type FILE is defined as:
20753 typedef char * FILE;
20756 This type is the stream type implemented I/O in the PIC18F devices.
20757 Also the standard input and output streams are declared in stdio.h:
20760 extern FILE * stdin;
20763 extern FILE * stdout;
20766 The FILE type is actually a generic pointer which defines one more type
20767 of generic pointers, the
20772 This new type has the format:
20776 \begin_inset Tabular
20777 <lyxtabular version="3" rows="2" columns="7">
20779 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20780 <column alignment="center" valignment="top" width="0">
20781 <column alignment="center" valignment="top" leftline="true" width="0">
20782 <column alignment="center" valignment="top" leftline="true" width="0">
20783 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20784 <column alignment="center" valignment="top" width="0">
20785 <column alignment="left" valignment="top" rightline="true" width="0">
20786 <row topline="true" bottomline="true">
20787 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20795 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20803 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20811 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20819 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20827 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20832 rest of the pointer
20835 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20844 <row topline="true" bottomline="true">
20845 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20853 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20861 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20869 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20877 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20885 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20897 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20902 upper byte high nubble is 0x2n, the rest are zeroes
20913 Currently implemented there are 3 types of streams defined:
20917 \begin_inset Tabular
20918 <lyxtabular version="3" rows="4" columns="4">
20920 <column alignment="center" valignment="top" leftline="true" width="0">
20921 <column alignment="center" valignment="top" leftline="true" width="0">
20922 <column alignment="center" valignment="top" leftline="true" width="0">
20923 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20924 <row topline="true" bottomline="true">
20925 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20933 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20941 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20949 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20958 <row topline="true">
20959 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20967 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20977 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20985 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20990 Writes/Reads characters via the USART peripheral
20994 <row topline="true">
20995 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21003 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21013 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21021 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21026 Writes/Reads characters via the MSSP peripheral
21030 <row topline="true" bottomline="true">
21031 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21039 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21049 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21057 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21062 Writes/Reads characters via used defined functions
21073 The stream identifiers are declared as macros in the stdio.h header.
21076 In the libc library there exist the functions that are used to write to
21077 each of the above streams.
21080 \labelwidthstring 00.00.0000
21092 _stream_usart_putchar writes a character at the USART stream
21094 \labelwidthstring 00.00.0000
21106 _stream_mssp_putchar writes a character at the MSSP stream
21108 \labelwidthstring 00.00.0000
21110 putchar dummy function.
21111 This writes a character to a user specified manner.
21114 In order to increase performance
21118 is declared in stdio.h as having its parameter in WREG (it has the wparam
21120 In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
21121 in a user-friendly way.
21126 is the name of the variable that holds the character to print.
21127 An example follows:
21130 #include <pic18fregs.h>
21142 PORTA = c; /* dump character c to PORTA */
21155 stdout = STREAM_USER; /* this is not necessary, since stdout points
21158 * by default to STREAM_USER */
21161 printf (¨This is a printf test
21169 \layout Subsubsection
21174 PIC16 contains an implementation of the printf-family of functions.
21175 There exist the following functions:
21178 extern unsigned int sprintf(char *buf, char *fmt, ...);
21181 extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
21186 extern unsigned int printf(char *fmt, ...);
21189 extern unsigned int vprintf(char *fmt, va_lista ap);
21194 extern unsigned int fprintf(FILE *fp, char *fmt, ...);
21197 extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
21200 For sprintf and vsprintf
21204 should normally be a data pointer where the resulting string will be placed.
21205 No range checking is done so the user should allocate the necessery buffer.
21206 For fprintf and vfprintf
21210 should be a stream pointer (i.e.
21211 stdout, STREAM_MSSP, etc...).
21212 \layout Subsubsection
21217 The PIC18F family of microcontrollers supports a number of interrupt sources.
21218 A list of these interrupts is shown in the following table:
21222 \begin_inset Tabular
21223 <lyxtabular version="3" rows="11" columns="4">
21225 <column alignment="left" valignment="top" leftline="true" width="0">
21226 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21227 <column alignment="left" valignment="top" leftline="true" width="0">
21228 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21229 <row topline="true" bottomline="true">
21230 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21238 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21246 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21254 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21263 <row topline="true">
21264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21272 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21277 PORTB change interrupt
21280 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21288 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21293 EEPROM/FLASH write complete interrupt
21297 <row topline="true">
21298 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21306 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21311 INT0 external interrupt
21314 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21322 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21327 Bus collision interrupt
21331 <row topline="true">
21332 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21340 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21345 INT1 external interrupt
21348 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21356 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21361 Low voltage detect interrupt
21365 <row topline="true">
21366 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21374 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21379 INT2 external interrupt
21382 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21390 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21395 Parallel slave port interrupt
21399 <row topline="true">
21400 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21408 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21413 CCP1 module interrupt
21416 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21424 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21429 AD convertion complete interrupt
21433 <row topline="true">
21434 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21442 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21447 CCP2 module interrupt
21450 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21458 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21463 USART receive interrupt
21467 <row topline="true">
21468 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21476 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21481 TMR0 overflow interrupt
21484 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21492 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21497 USART transmit interrupt
21501 <row topline="true">
21502 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21510 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21515 TMR1 overflow interrupt
21518 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21526 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21531 SSP receive/transmit interrupt
21535 <row topline="true">
21536 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21544 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21549 TMR2 matches PR2 interrupt
21552 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21559 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21567 <row topline="true" bottomline="true">
21568 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21576 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21581 TMR3 overflow interrupt
21584 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21591 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21606 The prototypes for these names are defined in the header file
21613 In order to simplify signal handling, a number of macros is provided:
21615 \labelwidthstring 00.00.0000
21617 DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
21618 high priority interrupts.
21623 is the function name to use.
21625 \labelwidthstring 00.00.0000
21627 DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
21628 low priority interrupt.
21633 is the function name to use.
21635 \labelwidthstring 00.00.0000
21637 DEF_HANDLER(sig,handler) define a handler for signal
21641 \labelwidthstring 00.00.0000
21643 END_DEF end the declaration of the dispatch table.
21646 Additionally there are two more macros to simplify the declaration of the
21649 \labelwidthstring 00.00.0000
21653 SIGHANDLER(handler)
21655 this declares the function prototype for the
21661 \labelwidthstring 00.00.0000
21663 SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
21666 An example of using the macros above is shown below:
21669 #include <pic18fregs.h>
21672 #include <signal.h>
21676 DEF_INTHIGH(high_int)
21679 DEF_HANDLER(SIG_TMR0, _tmr0_handler)
21682 DEF_HANDLER(SIG_BCOL, _bcol_handler)
21689 SIGHANDLER(_tmr0_handler)
21695 /* action to be taken when timer 0 overflows */
21702 SIGHANDLERNAKED(_bcol_handler)
21711 /* action to be taken when bus collision occurs */
21727 Special care should be taken when using the above scheme:
21730 do not place a colon (;) at the end of the DEF_* and END_DEF macros.
21733 when declaring SIGHANDLERNAKED handler never forget to use
21737 for proper returning.
21743 Here you can find some general tips for compiling programs with SDCC/pic16.
21744 \layout Subsubsection
21750 \begin_inset LatexCommand \index{PIC16!stack}
21754 size (that is 64 bytes) probably is enough for many programs.
21755 One must take care that when there are many levels of function nesting,
21756 or there is excessive usage of stack, its size should be extended.
21757 An example of such a case is the printf/sprintf family of functions.
21758 If you encounter problems like not being able to print integers, then you
21759 need to set the stack size around the maximum (256 for small stack model).
21760 The following diagram shows what happens when calling printf to print an
21764 printf () --> ltoa () --> ultoa () --> divschar ()
21767 It is should be understood that stack is easily consumed when calling complicate
21769 Using command line arguments like -
21779 -fommit-frame-pointer might reduce stack usage by not creating unnecessery
21781 Other ways to reduce stack usage may exist.
21787 The PIC16 Port currently does not pass SDCC's regression test
21788 \begin_inset LatexCommand \index{Regression test (PIC16)}
21793 \begin_inset LatexCommand \ref{sec:Quality-control}
21797 ) and thus the nightly regression tests for the PIC16 target are currently
21798 disabled for all hosts except for
21803 This means you can see the result of the PIC16 regression tests f.e.
21804 by checking the log files in
21805 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/regression_test_results/amd64-unknown-linux2.3/}
21809 (pick the most up to date file there, scroll down, lend a hand).
21815 There are several approaches to debugging your code.
21816 This chapter is meant to show your options and to give detail on some of
21821 When writing your code:
21824 write your code with debugging in mind (avoid duplicating code, put conceptually
21825 similar variables into structs, use structured code, have strategic points
21826 within your code where all variables are consistent, ...)
21829 run a syntax-checking tool like splint
21830 \begin_inset LatexCommand \index{splint (syntax checking tool)}
21835 \begin_inset LatexCommand \index{lint (syntax checking tool)}
21850 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
21857 for the high level code use a C-compiler (like f.e.
21858 GCC) to compile run and debug the code on your host.
21870 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
21874 ) on howto handle syntax extensions like __xdata, __at(), ...
21878 use another C-compiler to compile code for your target.
21879 Always an option but not recommended:) And not very likely to help you.
21880 If you seriously consider walking this path you should at least occasionally
21881 check portability of your code.
21882 Most commercial compiler vendors will offer an evaluation version so you
21883 can test compile your code or snippets of your code.
21886 Debugging on a simulator:
21889 there is a separate section about SDCDB (section
21890 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
21897 or (8051 specific) use a freeware/commercial simulator which interfaces
21899 \begin_inset LatexCommand \index{AOMF, AOMF51}
21904 \begin_inset LatexCommand \ref{OMF file}
21908 ) optionally generated by SDCC.
21911 Debugging On-target:
21914 use a MCU port pin to serially output debug data to the RS232 port of your
21916 You'll probably want some level shifting device typically involving a MAX232
21918 If the hardware serial port of the MCU is not available search for 'Software
21919 UART' in your favourite search machine.
21922 use an on-target monitor.
21923 In this context a monitor is a small program which usually accepts commands
21924 via a serial line and allows to set program counter, to single step through
21925 a program and read/write memory locations.
21926 For the 8051 good examples of monitors are paulmon and cmon51 (see section
21928 \begin_inset LatexCommand \ref{sec:Related-open-source-tools}
21935 toggle MCU port pins at strategic points within your code and use an oscilloscop
21939 digital oscilloscope
21942 \begin_inset LatexCommand \index{Oscilloscope}
21946 with deep trace memory is really helpful especially if you have to debug
21947 a realtime application.
21948 If you need to monitor more pins than your oscilloscope provides you can
21949 sometimes get away with a small R-2R network.
21950 On a single channel oscilloscope you could f.e.
21951 monitor 2 push-pull driven pins by connecting one via a 10\SpecialChar ~
21953 \begin_inset Formula $\Omega$
21956 resistor and the other one by a 5\SpecialChar ~
21958 \begin_inset Formula $\Omega$
21961 resistor to the oscilloscope probe (check output drive capability of the
21962 pins you want to monitor).
21963 If you need to monitor many more pins a
21983 \begin_inset LatexCommand \index{ICE (in circuit emulator)}
21988 Usually very expensive.
21989 And very nice to have too.
21990 And usually locks you (for years...) to the devices the ICE can emulate.
21994 use a remote debugger.
21995 In most 8-bit systems the symbol information is not available on the target,
21996 and a complete debugger is too bulky for the target system.
21997 Therefore usually a debugger on the host system connects to an on-target
21998 debugging stub which accepts only primitive commands.
22001 Terms to enter into your favourite search engine could be 'remote debugging',
22002 'gdb stub' or 'inferior debugger'.
22006 use an on target hardware debugger.
22007 Some of the more modern MCUs include hardware support for setting break
22008 points and monitoring/changing variables by using dedicated hardware pins.
22009 This facility doesn't require additional code to run on the target and
22014 doesn't affect runtime behaviour until a breakpoint is hit.
22015 For the mcs51 most hardware debuggers use the AOMF
22016 \begin_inset LatexCommand \index{AOMF, AOMF51}
22021 \begin_inset LatexCommand \ref{OMF file}
22032 if you are not familiar with any of the following terms you're likely to
22033 run into problems rather sooner than later:
22050 As an embedded programmer you
22054 to know them so why not look them up
22058 you have problems?)
22061 tell someone else about your problem (actually this is a surprisingly effective
22062 means to hunt down the bug even if the listener is not familiar with your
22064 As 'failure to communicate' is probably one of the job-induced deformations
22065 of an embedded programmer this is highly encouraged.
22068 Debugging with SDCDB
22069 \begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
22074 \begin_inset LatexCommand \index{SDCDB (debugger)}
22081 SDCC is distributed with a source level debugger
22082 \begin_inset LatexCommand \index{Debugger}
22087 The debugger uses a command line interface, the command repertoire of the
22088 debugger has been kept as close to gdb
22089 \begin_inset LatexCommand \index{gdb}
22093 (the GNU debugger) as possible.
22094 The configuration and build process is part of the standard compiler installati
22095 on, which also builds and installs the debugger in the target directory
22096 specified during configuration.
22097 The debugger allows you debug BOTH at the C source and at the ASM source
22101 Compiling for Debugging
22115 \begin_inset LatexCommand \index{-\/-debug}
22119 option must be specified for all files for which debug information is to
22121 The compiler generates a .adb file for each of these files.
22122 The linker creates the .cdb
22123 \begin_inset LatexCommand \index{<file>.cdb}
22128 \begin_inset LatexCommand \index{<file>.adb}
22132 files and the address information.
22133 This .cdb is used by the debugger.
22136 How the Debugger Works
22149 -debug option is specified the compiler generates extra symbol information
22150 some of which are put into the assembler source and some are put into the
22152 Then the linker creates the .cdb file from the individual .adb files with
22153 the address information for the symbols.
22154 The debugger reads the symbolic information generated by the compiler &
22155 the address information generated by the linker.
22156 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
22157 execution is controlled by the debugger.
22158 When a command is issued for the debugger, it translates it into appropriate
22159 commands for the simulator.
22160 (Currently SDCDM only connects to the simulator but
22165 \begin_inset LatexCommand \url{http://ec2drv.sf.net/}
22169 is an effort to connect directly to the hardware.)
22172 Starting the Debugger SDCDB
22175 The debugger can be started using the following command line.
22176 (Assume the file you are debugging has the file name foo).
22190 The debugger will look for the following files.
22193 foo.c - the source file.
22196 foo.cdb - the debugger symbol information file.
22199 foo.ihx - the Intel hex format
22200 \begin_inset LatexCommand \index{Intel hex format}
22207 SDCDB Command Line Options
22220 -directory=<source file directory> this option can used to specify the directory
22222 The debugger will look into the directory list specified for source, cdb
22224 The items in the directory list must be separated by ':', e.g.
22225 if the source files can be in the directories /home/src1 and /home/src2,
22236 -directory option should be -
22246 -directory=/home/src1:/home/src2.
22247 Note there can be no spaces in the option.
22251 -cd <directory> - change to the <directory>.
22254 -fullname - used by GUI front ends.
22257 -cpu <cpu-type> - this argument is passed to the simulator please see the
22258 simulator docs for details.
22261 -X <Clock frequency > this options is passed to the simulator please see
22262 the simulator docs for details.
22265 -s <serial port file> passed to simulator see the simulator docs for details.
22268 -S <serial in,out> passed to simulator see the simulator docs for details.
22271 -k <port number> passed to simulator see the simulator docs for details.
22274 SDCDB Debugger Commands
22277 As mentioned earlier the command interface for the debugger has been deliberatel
22278 y kept as close the GNU debugger gdb, as possible.
22279 This will help the integration with existing graphical user interfaces
22280 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
22281 If you use a graphical user interface for the debugger you can skip this
22283 \layout Subsubsection*
22285 break [line | file:line | function | file:function]
22288 Set breakpoint at specified line or function:
22297 sdcdb>break foo.c:100
22299 sdcdb>break funcfoo
22301 sdcdb>break foo.c:funcfoo
22302 \layout Subsubsection*
22304 clear [line | file:line | function | file:function ]
22307 Clear breakpoint at specified line or function:
22316 sdcdb>clear foo.c:100
22318 sdcdb>clear funcfoo
22320 sdcdb>clear foo.c:funcfoo
22321 \layout Subsubsection*
22326 Continue program being debugged, after breakpoint.
22327 \layout Subsubsection*
22332 Execute till the end of the current function.
22333 \layout Subsubsection*
22338 Delete breakpoint number 'n'.
22339 If used without any option clear ALL user defined break points.
22340 \layout Subsubsection*
22342 info [break | stack | frame | registers ]
22345 info break - list all breakpoints
22348 info stack - show the function call stack.
22351 info frame - show information about the current execution frame.
22354 info registers - show content of all registers.
22355 \layout Subsubsection*
22360 Step program until it reaches a different source line.
22361 Note: pressing <return> repeats the last command.
22362 \layout Subsubsection*
22367 Step program, proceeding through subroutine calls.
22368 \layout Subsubsection*
22373 Start debugged program.
22374 \layout Subsubsection*
22379 Print type information of the variable.
22380 \layout Subsubsection*
22385 print value of variable.
22386 \layout Subsubsection*
22391 load the given file name.
22392 Note this is an alternate method of loading file for debugging.
22393 \layout Subsubsection*
22398 print information about current frame.
22399 \layout Subsubsection*
22404 Toggle between C source & assembly source.
22405 \layout Subsubsection*
22407 ! simulator command
22410 Send the string following '!' to the simulator, the simulator response is
22412 Note the debugger does not interpret the command being sent to the simulator,
22413 so if a command like 'go' is sent the debugger can loose its execution
22414 context and may display incorrect values.
22415 \layout Subsubsection*
22422 My name is Bobby Brown"
22425 Interfacing SDCDB with DDD
22428 The screenshot was converted from png to eps with:
22429 \begin_inset Quotes sld
22432 bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
22433 \begin_inset Quotes srd
22436 which produces a pretty compact eps file which is free from compression
22440 The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
22441 as this broke the build system on Sourceforge (pdf-file was broken.
22442 pdflatex does not accept eps files).
22460 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
22466 shows a screenshot of a debugging session with DDD
22467 \begin_inset LatexCommand \index{DDD (debugger)}
22471 (Unix only) on a simulated 8032.
22472 The debugging session might not run as smoothly as the screenshot suggests.
22473 The debugger allows setting of breakpoints, displaying and changing variables,
22474 single stepping through C and assembler code.
22477 The source was compiled with
22500 -debug ddd_example.c
22513 and DDD was invoked with
22520 ddd -debugger 'sdcdb -cpu 8032 ddd_example'
22523 Interfacing SDCDB with XEmacs
22524 \begin_inset LatexCommand \index{XEmacs}
22529 \begin_inset LatexCommand \index{Emacs}
22536 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
22537 sdcdb.el and sdcdbsrc.el.
22538 These two files can be found in the $(prefix)/bin directory after the installat
22540 These files need to be loaded into XEmacs for the interface to work.
22541 This can be done at XEmacs startup time by inserting the following into
22542 your '.xemacs' file (which can be found in your HOME directory):
22548 (load-file sdcdbsrc.el)
22554 .xemacs is a lisp file so the () around the command is REQUIRED.
22555 The files can also be loaded dynamically while XEmacs is running, set the
22556 environment variable 'EMACSLOADPATH' to the installation bin directory
22557 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
22558 To start the interface enter the following command:
22572 You will prompted to enter the file name to be debugged.
22577 The command line options that are passed to the simulator directly are bound
22578 to default values in the file sdcdbsrc.el.
22579 The variables are listed below, these values maybe changed as required.
22582 sdcdbsrc-cpu-type '51
22585 sdcdbsrc-frequency '11059200
22588 sdcdbsrc-serial nil
22591 The following is a list of key mapping for the debugger interface.
22602 ;;key\SpecialChar ~
22616 binding\SpecialChar ~
22640 ;;---\SpecialChar ~
22654 -------\SpecialChar ~
22696 sdcdb-next-from-src\SpecialChar ~
22724 sdcdb-back-from-src\SpecialChar ~
22752 sdcdb-cont-from-src\SpecialChar ~
22762 SDCDB continue command
22780 sdcdb-step-from-src\SpecialChar ~
22808 sdcdb-whatis-c-sexp\SpecialChar ~
22818 SDCDB ptypecommand for data at
22885 sdcdbsrc-delete\SpecialChar ~
22899 SDCDB Delete all breakpoints if no arg
22948 given or delete arg (C-u arg x)
22966 sdcdbsrc-frame\SpecialChar ~
22981 SDCDB Display current frame if no arg,
23030 given or display frame arg
23097 sdcdbsrc-goto-sdcdb\SpecialChar ~
23107 Goto the SDCDB output buffer
23125 sdcdb-print-c-sexp\SpecialChar ~
23136 SDCDB print command for data at
23203 sdcdbsrc-goto-sdcdb\SpecialChar ~
23213 Goto the SDCDB output buffer
23231 sdcdbsrc-mode\SpecialChar ~
23247 Toggles Sdcdbsrc mode (turns it off)
23262 sdcdb-finish-from-src\SpecialChar ~
23270 SDCDB finish command
23285 sdcdb-break\SpecialChar ~
23303 Set break for line with point
23318 sdcdbsrc-mode\SpecialChar ~
23334 Toggle Sdcdbsrc mode
23349 sdcdbsrc-srcmode\SpecialChar ~
23372 Here are a few guidelines that will help the compiler generate more efficient
23373 code, some of the tips are specific to this compiler others are generally
23374 good programming practice.
23377 Use the smallest data type to represent your data-value.
23378 If it is known in advance that the value is going to be less than 256 then
23379 use an 'unsigned char' instead of a 'short' or 'int'.
23380 Please note, that ANSI C requires both signed and unsigned chars to be
23381 promoted to 'signed int'
23382 \begin_inset LatexCommand \index{promotion to signed int}
23387 \begin_inset Marginal
23398 before doing any operation.
23400 \begin_inset LatexCommand \index{type promotion}
23405 \begin_inset LatexCommand \label{type promotion}
23409 can be omitted, if the result is the same.
23410 The effect of the promotion rules together with the sign-extension is often
23417 unsigned char uc = 0xfe;
23419 if (uc * uc < 0) /* this is true! */
23438 (int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
23448 (unsigned char) -12 / (signed char) -3 = ...
23451 No, the result is not 4:
23456 (int) (unsigned char) -12 / (int) (signed char) -3 =
23458 (int) (unsigned char) 0xf4 / (int) (signed char) 0xfd =
23460 (int) 0x00f4 / (int) 0xfffd =
23462 (int) 0x00f4 / (int) 0xfffd =
23464 (int) 244 / (int) -3 =
23466 (int) -81 = (int) 0xffaf;
23469 Don't complain, that gcc gives you a different result.
23470 gcc uses 32 bit ints, while SDCC uses 16 bit ints.
23471 Therefore the results are different.
23474 \begin_inset Quotes sld
23478 \begin_inset Quotes srd
23486 If well-defined overflow characteristics are important and negative values
23487 are not, or if you want to steer clear of sign-extension problems when
23488 manipulating bits or bytes, use one of the corresponding unsigned types.
23489 (Beware when mixing signed and unsigned values in expressions, though.)
23491 Although character types (especially unsigned char) can be used as "tiny"
23492 integers, doing so is sometimes more trouble than it's worth, due to unpredicta
23493 ble sign extension and increased code size.
23497 Use unsigned when it is known in advance that the value is not going to
23499 This helps especially if you are doing division or multiplication, bit-shifting
23500 or are using an array index.
23503 NEVER jump into a LOOP.
23506 Declare the variables to be local
23507 \begin_inset LatexCommand \index{local variables}
23511 whenever possible, especially loop control variables (induction).
23514 Since the compiler does not always do implicit integral promotion, the programme
23515 r should do an explicit cast when integral promotion is required.
23518 Reducing the size of division, multiplication & modulus operations can reduce
23519 code size substantially.
23520 Take the following code for example.
23526 foobar(unsigned int p1, unsigned char ch)
23534 unsigned char ch1 = p1 % ch ;
23545 For the modulus operation the variable ch will be promoted to unsigned int
23546 first then the modulus operation will be performed (this will lead to a
23547 call to support routine _moduint()), and the result will be casted to a
23549 If the code is changed to
23554 foobar(unsigned int p1, unsigned char ch)
23562 unsigned char ch1 = (unsigned char)p1 % ch ;
23573 It would substantially reduce the code generated (future versions of the
23574 compiler will be smart enough to detect such optimization opportunities).
23578 Have a look at the assembly listing to get a
23579 \begin_inset Quotes sld
23583 \begin_inset Quotes srd
23586 for the code generation.
23589 Porting code from or to other compilers
23590 \begin_inset LatexCommand \label{sec:Porting-code-to-other-compilers}
23597 check whether endianness of the compilers differs and adapt where needed.
23600 check the device specific header files
23601 \begin_inset LatexCommand \index{Header files}
23606 \begin_inset LatexCommand \index{Include files}
23610 for compiler specific syntax.
23611 Eventually include the file <compiler.h
23612 \begin_inset LatexCommand \index{compiler.h (include file)}
23617 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}
23621 to allow using common header files.
23624 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}
23631 check whether the startup code contains the correct initialization (watchdog,
23635 check whether the sizes of short, int, long match.
23638 check if some 16 or 32 bit hardware registers require a specific addressing
23639 order (least significant or most significant byte first) and adapt if needed
23648 relate to time and not to lower/upper memory location here, so this is
23653 the same as endianness).
23656 check whether the keyword
23660 is used where needed.
23661 The compilers might differ in their optimization characteristics (as different
23662 versions of the same compiler might also use more clever optimizations
23663 this is good idea anyway).
23665 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
23672 check that the compilers are not told to supress warnings.
23675 check and convert compiler specific extensions (interrupts, memory areas,
23679 check for differences in type promotion.
23680 Especially check for math operations on
23689 For the sake of C99 compatibility SDCC will probably promote these to
23693 more often than other compilers.
23694 Eventually insert explicit casts to
23703 Also check that the ~\SpecialChar ~
23705 \begin_inset LatexCommand \index{\~\/ Operator}
23712 \begin_inset LatexCommand \index{bit}
23718 variables, use the !\SpecialChar ~
23721 \begin_inset LatexCommand \ref{type promotion}
23726 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23733 check the assembly code generated for interrupt routines (f.e.
23734 for calls to possibly non-reentrant library functions).
23737 check whether timing loops result in proper timing (or preferably consider
23738 a rewrite of the code with timer based delays instead).
23741 check for differences in printf parameters (some compilers push (va_arg
23742 \begin_inset LatexCommand \index{vararg, va\_arg}
23746 ) char variables as
23750 others push them as
23756 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23763 check the resulting memory map
23764 \begin_inset LatexCommand \index{Memory map}
23769 Usage of different memory spaces: code, stack, data (for mcs51/ds390 additional
23770 ly idata, pdata, xdata).
23771 Eventually check if unexpected library functions are included.
23775 \begin_inset LatexCommand \index{Tools}
23779 included in the distribution
23783 \begin_inset Tabular
23784 <lyxtabular version="3" rows="12" columns="3">
23786 <column alignment="left" valignment="top" leftline="true" width="0pt">
23787 <column alignment="left" valignment="top" leftline="true" width="0pt">
23788 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
23789 <row topline="true" bottomline="true">
23790 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23798 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23806 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23815 <row topline="true">
23816 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23824 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23829 Simulator for various architectures
23832 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23841 <row topline="true">
23842 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23850 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23856 \begin_inset LatexCommand \index{Header files}
23861 \begin_inset LatexCommand \index{Include files}
23868 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23873 sdcc/support/scripts
23877 <row topline="true">
23878 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23886 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23891 header file conversion
23894 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23899 sdcc/support/scripts
23903 <row topline="true">
23904 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23912 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23920 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23938 <row topline="true">
23939 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23947 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23955 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23973 <row topline="true">
23974 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23982 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23990 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24008 <row topline="true">
24009 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24017 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24025 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24043 <row topline="true">
24044 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24052 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24060 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24078 <row topline="true">
24079 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24087 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24095 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24113 <row topline="true">
24114 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24122 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24130 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24148 <row topline="true" bottomline="true">
24149 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24157 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24163 \begin_inset LatexCommand \index{packihx (tool)}
24170 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24198 \begin_inset LatexCommand \index{Documentation}
24202 included in the distribution
24206 \begin_inset Tabular
24207 <lyxtabular version="3" rows="10" columns="2">
24209 <column alignment="left" valignment="top" leftline="true" width="0">
24210 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
24211 <row topline="true" bottomline="true">
24212 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24220 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24225 Where to get / filename
24229 <row topline="true">
24230 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24235 SDCC Compiler User Guide
24238 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24243 You're reading it right now
24247 <row topline="true">
24248 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24256 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24265 <row topline="true">
24266 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24272 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
24277 \begin_inset LatexCommand \index{Assembler documentation}
24281 Assemblers and ASLINK
24282 \begin_inset LatexCommand \index{aslink}
24287 \begin_inset LatexCommand \index{Linker documentation}
24294 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24299 sdcc/as/doc/asxhtm.html
24303 <row topline="true">
24304 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24309 SDCC regression test
24310 \begin_inset LatexCommand \index{Regression test}
24317 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24322 sdcc/doc/test_suite_spec.pdf
24326 <row topline="true">
24327 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24335 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24344 <row topline="true">
24345 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24350 Notes on debugging with SDCDB
24351 \begin_inset LatexCommand \index{SDCDB (debugger)}
24358 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24363 sdcc/debugger/README
24367 <row topline="true">
24368 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24373 Software simulator for microcontrollers
24376 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24403 <row topline="true">
24404 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24409 Temporary notes on the pic16
24410 \begin_inset LatexCommand \index{PIC16}
24417 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24422 sdcc/src/pic16/NOTES
24426 <row topline="true" bottomline="true">
24427 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24432 SDCC internal documentation (debugging file format)
24435 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24471 Related open source tools
24472 \begin_inset LatexCommand \label{sec:Related-open-source-tools}
24477 \begin_inset LatexCommand \index{Related tools}
24485 \begin_inset Tabular
24486 <lyxtabular version="3" rows="14" columns="3">
24488 <column alignment="left" valignment="top" leftline="true" width="0pt">
24489 <column alignment="block" valignment="top" leftline="true" width="30line%">
24490 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
24491 <row topline="true" bottomline="true">
24492 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24500 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24508 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24517 <row topline="true">
24518 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24524 \begin_inset LatexCommand \index{gpsim (pic simulator)}
24531 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24539 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24545 \begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
24553 <row topline="true">
24554 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24560 \begin_inset LatexCommand \index{gputils (pic tools)}
24567 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24575 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24581 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
24589 <row topline="true">
24590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24598 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24606 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24612 \begin_inset LatexCommand \url{http://freshmeat.net/projects/flp5/}
24620 <row topline="true">
24621 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24629 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24634 Tools for Silicon Laboratories JTAG debug adapter, partly based on SDCDB
24638 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24644 \begin_inset LatexCommand \url{http://sourceforge.net/projects/ec2drv}
24652 <row topline="true">
24653 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24659 \begin_inset LatexCommand \index{indent (source formatting tool)}
24666 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24671 Formats C source - Master of the white spaces
24674 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24680 \begin_inset LatexCommand \url{http://directory.fsf.org/GNU/indent.html}
24688 <row topline="true">
24689 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24695 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
24702 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24707 Object file conversion, checksumming, ...
24710 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24716 \begin_inset LatexCommand \url{http://sourceforge.net/projects/srecord}
24724 <row topline="true">
24725 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24731 \begin_inset LatexCommand \index{objdump (tool)}
24738 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24743 Object file conversion, ...
24746 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24751 Part of binutils (should be there anyway)
24755 <row topline="true">
24756 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24764 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24769 8051 monitor (hex up-/download, single step, disassemble)
24772 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24778 \begin_inset LatexCommand \url{http://sourceforge.net/projects/cmon51}
24786 <row topline="true">
24787 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24793 \begin_inset LatexCommand \index{doxygen (source documentation tool)}
24800 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24805 Source code documentation system
24808 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24814 \begin_inset LatexCommand \url{http://www.doxygen.org}
24822 <row topline="true">
24823 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24831 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24836 IDE (has anyone tried integrating SDCC & SDCDB? Unix only)
24839 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24845 \begin_inset LatexCommand \url{http://www.kdevelop.org}
24853 <row topline="true">
24854 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24862 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24867 8051 monitor (hex up-/download, single step, disassemble)
24870 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24876 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/paulmon2.html}
24884 <row topline="true">
24885 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24891 \begin_inset LatexCommand \index{splint (syntax checking tool)}
24898 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24903 Statically checks c sources (see
24904 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
24911 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24917 \begin_inset LatexCommand \url{http://www.splint.org}
24925 <row topline="true" bottomline="true">
24926 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24932 \begin_inset LatexCommand \index{DDD (debugger)}
24939 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24944 Debugger, serves nicely as GUI to SDCDB
24945 \begin_inset LatexCommand \index{SDCDB (debugger)}
24952 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24958 \begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
24975 Related documentation / recommended reading
24979 \begin_inset Tabular
24980 <lyxtabular version="3" rows="7" columns="3">
24982 <column alignment="left" valignment="top" leftline="true" width="0pt">
24983 <column alignment="center" valignment="top" leftline="true" width="0">
24984 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
24985 <row topline="true" bottomline="true">
24986 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24994 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25002 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25011 <row topline="true">
25012 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25029 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25035 \begin_inset LatexCommand \index{C Reference card}
25042 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25048 \begin_inset LatexCommand \url{http://refcards.com/refcards/c/index.html}
25056 <row topline="true">
25057 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25065 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25071 \begin_inset LatexCommand \index{C FAQ}
25078 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25084 \begin_inset LatexCommand \url{http://www.c-faq.com}
25092 <row topline="true">
25093 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25101 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25107 \begin_inset Quotes sld
25111 \begin_inset Quotes srd
25117 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25125 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
25133 <row topline="true">
25134 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25142 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25148 \begin_inset Quotes sld
25151 Extensions for Embedded C
25152 \begin_inset Quotes srd
25158 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25166 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1021.pdf}
25174 <row topline="true">
25175 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25182 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25187 Latest datasheet of target CPU
25190 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25199 <row topline="true" bottomline="true">
25200 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25207 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25212 Revision history of datasheet
25215 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25233 Application notes specifically for SDCC
25236 SDCC makes no claims about the completeness of this list and about up-to-datenes
25237 s or correctness of the application notes
25238 \begin_inset LatexCommand \index{Application notes}
25248 \begin_inset Tabular
25249 <lyxtabular version="3" rows="7" columns="3">
25251 <column alignment="block" valignment="top" leftline="true" width="17col%">
25252 <column alignment="block" valignment="top" leftline="true" width="27col%">
25253 <column alignment="block" valignment="top" leftline="true" rightline="true" width="57col%">
25254 <row topline="true" bottomline="true">
25255 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25265 <cell alignment="left" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
25275 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25286 <row topline="true">
25287 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25297 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25304 Using the SDCC Compiler for the DS80C400
25305 \begin_inset LatexCommand \index{DS80C400}
25312 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25320 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3346.pdf}
25328 <row topline="true">
25329 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25339 <cell multicolumn="1" alignment="left" valignment="top" topline="true" leftline="true" usebox="none" width="30line%">
25346 Using the Free SDCC C Compiler to Develop Firmware for the DS89C420/430/440/450
25347 \begin_inset LatexCommand \index{DS89C4x0}
25351 Family of Microcontrollers
25354 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25362 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3477.pdf}
25370 <row topline="true">
25371 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25378 Silicon Laboratories / Cygnal
25381 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25388 Integrating SDCC 8051 Tools Into The Silicon Labs IDE
25389 \begin_inset LatexCommand \index{IDE}
25396 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25404 \begin_inset LatexCommand \url{http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/en/an198.pdf}
25412 <row topline="true">
25413 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25420 Ramtron / Goal Semiconductor
25423 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25430 Interfacing SDCC to Syn and Textpad
25433 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25441 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25449 <row topline="true">
25450 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25457 Ramtron / Goal Semiconductor
25460 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25467 Installing and Configuring SDCC and Crimson Editor
25470 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25478 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25486 <row topline="true" bottomline="true">
25487 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25497 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25504 MSC12xx Programming with SDCC
25507 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25515 \begin_inset LatexCommand \url{http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sbaa109&fileType=pdf}
25533 Some questions answered, some pointers given - it might be time to in turn
25541 can you solve your project with the selected microcontroller? Would you
25542 find out early or rather late that your target is too small/slow/whatever?
25543 Can you switch to a slightly better device if it doesn't fit?
25546 should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
25547 and/or another programming language be more adequate? Would an operating
25548 system on the target device help?
25551 if you solved the problem, will the marketing department be happy?
25554 if the marketing department is happy, will customers be happy?
25557 if you're the project manager, marketing department and maybe even the customer
25558 in one person, have you tried to see the project from the outside?
25561 is the project done if you think it is done? Or is just that other interface/pro
25562 tocol/feature/configuration/option missing? How about website, manual(s),
25563 internationali(z|s)ation, packaging, labels, 2nd source for components,
25564 electromagnetic compatability/interference, documentation for production,
25565 production test software, update mechanism, patent issues?
25568 is your project adequately positioned in that magic triangle: fame, fortune,
25572 Maybe not all answers to these questions are known and some answers may
25577 , nevertheless knowing these questions may help you to avoid burnout
25583 burnout is bad for electronic devices, programmers and motorcycle tyres
25587 Chances are you didn't want to hear some of them...
25591 \begin_inset LatexCommand \index{Support}
25598 SDCC has grown to be a large project.
25599 The compiler alone (without the preprocessor, assembler and linker) is
25600 well over 150,000 lines of code (blank stripped).
25601 The open source nature of this project is a key to its continued growth
25603 You gain the benefit and support of many active software developers and
25605 Is SDCC perfect? No, that's why we need your help.
25606 The developers take pride in fixing reported bugs.
25607 You can help by reporting the bugs and helping other SDCC users.
25608 There are lots of ways to contribute, and we encourage you to take part
25609 in making SDCC a great software package.
25613 The SDCC project is hosted on the SDCC sourceforge site at
25614 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
25619 You'll find the complete set of mailing lists
25620 \begin_inset LatexCommand \index{Mailing list(s)}
25624 , forums, bug reporting system, patch submission
25625 \begin_inset LatexCommand \index{Patch submission}
25630 \begin_inset LatexCommand \index{download}
25634 area and Subversion code repository
25635 \begin_inset LatexCommand \index{Subversion code repository}
25643 \begin_inset LatexCommand \index{Bug reporting}
25648 \begin_inset LatexCommand \index{Reporting bugs}
25655 The recommended way of reporting bugs is using the infrastructure of the
25657 You can follow the status of bug reports there and have an overview about
25661 Bug reports are automatically forwarded to the developer mailing list and
25662 will be fixed ASAP.
25663 When reporting a bug, it is very useful to include a small test program
25664 (the smaller the better) which reproduces the problem.
25665 If you can isolate the problem by looking at the generated assembly code,
25666 this can be very helpful.
25667 Compiling your program with the -
25678 \begin_inset LatexCommand \index{-\/-dumpall}
25682 option can sometimes be useful in locating optimization problems.
25683 When reporting a bug please make sure you:
25686 Attach the code you are compiling with SDCC.
25690 Specify the exact command you use to run SDCC, or attach your Makefile.
25694 Specify the SDCC version (type "
25700 "), your platform, and operating system.
25704 Provide an exact copy of any error message or incorrect output.
25708 Put something meaningful in the subject of your message.
25711 Please attempt to include these 5 important parts, as applicable, in all
25712 requests for support or when reporting any problems or bugs with SDCC.
25713 Though this will make your message lengthy, it will greatly improve your
25714 chance that SDCC users and developers will be able to help you.
25715 Some SDCC developers are frustrated by bug reports without code provided
25716 that they can use to reproduce and ultimately fix the problem, so please
25717 be sure to provide sample code if you are reporting a bug!
25720 Please have a short check that you are using a recent version of SDCC and
25721 the bug is not yet known.
25722 This is the link for reporting bugs:
25723 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
25728 With SDCC on average having more than 200 downloads
25729 \begin_inset LatexCommand \index{download}
25733 on sourceforge per day
25739 220 daily downloads on average Jan-Sept 2006 and about 150 daily downloads
25740 between 2002 and 2005.
25741 This does not include other methods of distribution.
25744 there must be some users.
25745 So it's not exactly easy to find a new bug.
25746 If you find one we need it:
25748 reporting bugs is good
25753 Requesting Features
25754 \begin_inset LatexCommand \label{sub:Requesting-Features}
25759 \begin_inset LatexCommand \index{Feature request}
25764 \begin_inset LatexCommand \index{Requesting features}
25771 Like bug reports feature requests are forwarded to the developer mailing
25773 This is the link for requesting features:
25774 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
25784 Like bug reports contributed patches are forwarded to the developer mailing
25786 This is the link for submitting patches
25787 \begin_inset LatexCommand \index{Patch submission}
25792 \begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}
25799 You need to specify some parameters to the
25803 command for the patches to be useful.
25804 If you modified more than one file a patch created f.e.
25809 \begin_inset Quotes sld
25812 diff -Naur unmodified_directory modified_directory >my_changes.patch
25813 \begin_inset Quotes srd
25819 will be fine, otherwise
25823 \begin_inset Quotes sld
25826 diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
25827 \begin_inset Quotes srd
25840 These links should take you directly to the
25841 \begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
25851 Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
25852 automated messages (mid 2003)
25856 \begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
25861 \begin_inset LatexCommand \index{Mailing list(s)}
25865 and forums are archived and searchable so if you are lucky someone already
25866 had a similar problem.
25867 While mails to the lists themselves are delivered promptly their web front
25868 end on sourceforge sometimes shows a severe time lag (up to several weeks),
25869 if you're seriously using SDCC please consider subscribing to the lists.
25875 You can follow the status of the Subversion version
25876 \begin_inset LatexCommand \index{version}
25880 of SDCC by watching the Changelog
25881 \begin_inset LatexCommand \index{Changelog}
25885 in the Subversion repository
25888 \begin_inset LatexCommand \htmlurl{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}
25895 Subversion Source Code Repository
25904 or the filenames of the snapshot versions of SDCC include date and its
25906 \begin_inset LatexCommand \index{Subversion code repository}
25911 Subversion allows to download the source of recent or previous versions
25913 \begin_inset LatexCommand \url{http://sourceforge.net/svn/?group_id=599}
25917 (by number or by date).
25918 An on-line source code browser and detailled instructions are also available
25920 SDCC versions starting from 1999 up to now are available (currently the
25921 versions prior to the conversion from cvs
25922 \begin_inset LatexCommand \index{cvs|see{Subversion}}
25926 to Subversion (April 2006) are either by accessible by Subversion or by
25931 \begin_inset LatexCommand \index{Release policy}
25938 Historically there often were long delays between official releases and
25939 the sourceforge download area tends to get not updated at all.
25940 Excuses in the past might have referred to problems with live range analysis,
25941 but as this was fixed a while ago, the current problem is that another
25942 excuse has to be found.
25943 Kidding aside, we have to get better there! On the other hand there are
25944 daily snapshots available at
25945 \begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
25949 , and you can always build the very last version (hopefully with many bugs
25950 fixed, and features added) from the source code available at
25951 \begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
25959 \begin_inset LatexCommand \index{Examples}
25966 You'll find some small examples in the directory
25968 sdcc/device/examples/.
25971 More examples and libraries are available at
25973 The SDCC Open Knowledge Resource
25974 \begin_inset LatexCommand \url{http://sdccokr.dl9sec.de/}
25981 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}
25988 I did insert a reference to Paul's web site here although it seems rather
25989 dedicated to a specific 8032 board (I think it's okay because it f.e.
25990 shows LCD/Harddisc interface and has a free 8051 monitor.
25991 Independent 8032 board vendors face hard competition of heavily subsidized
25992 development boards anyway).
25995 Maybe we should include some links to real world applications.
25996 Preferably pointer to pointers (one for each architecture) so this stays
26001 \begin_inset LatexCommand \label{sec:Quality-control}
26006 \begin_inset LatexCommand \index{Quality control}
26013 The compiler is passed through nightly compile and build checks.
26019 \begin_inset LatexCommand \index{Regression test}
26023 check that SDCC itself compiles flawlessly on several host platforms (i386,
26024 Opteron, 64 bit Alpha, ppc64, MacOS X on PPC, Solaris on Sparc) and checks
26025 the quality of the code generated by SDCC by running the code for several
26026 target platforms through simulators.
26027 The regression test suite comprises more than 100 files which expand to
26028 more than 500 test cases which include more than 4500 tests.
26029 The results of these tests are published daily on SDCC's snapshot page
26030 (click on the red or green symbols on the right side of
26031 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
26038 There is a separate document
26041 \begin_inset LatexCommand \index{Test suite}
26048 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}
26052 about the regression test suite.
26055 You'll find the test code in the directory
26057 sdcc/support/regression
26060 You can run these tests manually by running
26064 in this directory (or f.e.
26069 \begin_inset Quotes sld
26073 \begin_inset Quotes srd
26079 if you don't want to run the complete tests).
26080 The test code might also be interesting if you want to look for examples
26081 \begin_inset LatexCommand \index{Examples}
26085 checking corner cases of SDCC or if you plan to submit patches
26086 \begin_inset LatexCommand \index{Patch submission}
26093 The 14bit pic port uses a different set of regression tests
26094 \begin_inset LatexCommand \index{Regression test (PIC14)}
26098 , you'll find them in the directory
26100 sdcc/src/regression
26105 Use of SDCC in Education
26118 the phrase "use in education" might evoke the association "
26122 fit for use in education".
26123 This connotation is not intended but nevertheless risked as the licensing
26124 of SDCC makes it difficult to offer educational discounts
26128 If your rationales are to:
26131 give students a chance to understand the
26135 steps of code generation
26138 have a curriculum that can be extended for years.
26139 Then you could use an fpga board as target and your curriculum will seamlessly
26140 extend from logic synthesis (
26141 \begin_inset LatexCommand \url[http://www.opencores.org]{opencores.org}
26146 \begin_inset LatexCommand \url[Oregano]{http://www.oregano.at/ip/ip01.htm}
26150 ), over assembly programming, to C to FPGA compilers (
26151 \begin_inset LatexCommand \url[FPGAC]{http://sf.net/projects/fpgac}
26158 be able to insert excursions about skills like using a revision control
26159 system, submitting/applying patches, using a type-setting (as opposed to
26160 word-processing) engine LyX/LaTeX, using
26161 \begin_inset LatexCommand \url[SourceForge]{http://www.sf.net}
26166 \begin_inset LatexCommand \url[netiquette]{http://en.wikipedia.org/wiki/Netiquette}
26170 , understanding BSD/LGPL/GPL/Proprietary licensing, growth models of Open
26171 Source Software, CPU simulation, compiler regression tests
26172 \begin_inset LatexCommand \index{Regression test}
26179 And if there should be a shortage of ideas then you can always point students
26180 to the ever-growing feature request list
26181 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
26188 not tie students to a specific host platform and instead allow them to use
26193 choice (among them Alpha, i386, i386_64, MacOs, Mips, Sparc, Windows and
26195 \begin_inset LatexCommand \url[OLPC]{http://www.laptop.org}
26202 not encourage students to use illegal copies of educational software
26205 be immune to licensing/availability/price changes of the chosen tool chain
26208 be able to change to a new target platform without having to adopt a new
26212 have complete control over and insight into the tool chain
26215 make your students aware about the pros and cons of open source software
26219 give back to the public as you are probably at least partially publically
26223 give students a chance to publically prove their skills and to possibly
26224 see a world wide impact
26227 then SDCC is probably among the first choices.
26228 Well, probably SDCC might be the only choice.
26231 SDCC Technical Data
26235 \begin_inset LatexCommand \index{Optimizations}
26242 SDCC performs a host of standard optimizations in addition to some MCU specific
26247 Sub-expression Elimination
26248 \begin_inset LatexCommand \index{Subexpression elimination}
26255 The compiler does local and
26281 will be translated to
26293 Some subexpressions are not as obvious as the above example, e.g.:
26303 In this case the address arithmetic a->b[i] will be computed only once;
26304 the equivalent code in C would be.
26316 The compiler will try to keep these temporary variables in registers.
26319 Dead-Code Elimination
26320 \begin_inset LatexCommand \index{Dead-code elimination}
26341 i = 1; \SpecialChar ~
26350 global = 1;\SpecialChar ~
26363 global = 3;\SpecialChar ~
26388 \begin_inset LatexCommand \index{Copy propagation}
26444 Note: the dead stores created by this copy propagation will be eliminated
26445 by dead-code elimination.
26449 \begin_inset LatexCommand \index{Loop optimization}
26454 \begin_inset LatexCommand \label{sub:Loop-Optimizations}
26461 Two types of loop optimizations are done by SDCC
26469 of loop induction variables.
26470 In addition to the strength reduction the optimizer marks the induction
26471 variables and the register allocator tries to keep the induction variables
26472 in registers for the duration of the loop.
26473 Because of this preference of the register allocator
26474 \begin_inset LatexCommand \index{Register allocation}
26478 , loop induction optimization causes an increase in register pressure, which
26479 may cause unwanted spilling of other temporary variables into the stack
26480 \begin_inset LatexCommand \index{stack}
26485 The compiler will generate a warning message when it is forced to allocate
26486 extra space either on the stack or data space.
26487 If this extra space allocation is undesirable then induction optimization
26488 can be eliminated either for the entire source file (with -
26498 -noinduction option) or for a given function only using #pragma\SpecialChar ~
26500 \begin_inset LatexCommand \index{\#pragma noinduction}
26513 for (i = 0 ; i < 100 ; i ++)
26529 for (i = 0; i < 100; i++)
26538 As mentioned previously some loop invariants are not as apparent, all static
26539 address computations are also moved out of the loop.
26544 \begin_inset LatexCommand \index{Strength reduction}
26548 , this optimization substitutes an expression by a cheaper expression:
26553 for (i=0;i < 100; i++)
26571 for (i=0;i< 100;i++) {
26577 ar[itemp1] = itemp2;
26594 The more expensive multiplication
26595 \begin_inset LatexCommand \index{Multiplication}
26599 is changed to a less expensive addition.
26603 \begin_inset LatexCommand \index{Loop reversing}
26610 This optimization is done to reduce the overhead of checking loop boundaries
26611 for every iteration.
26612 Some simple loops can be reversed and implemented using a
26613 \begin_inset Quotes eld
26616 decrement and jump if not zero
26617 \begin_inset Quotes erd
26621 SDCC checks for the following criterion to determine if a loop is reversible
26622 (note: more sophisticated compilers use data-dependency analysis to make
26623 this determination, SDCC uses a more simple minded analysis).
26626 The 'for' loop is of the form
26632 for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
26642 The <for body> does not contain
26643 \begin_inset Quotes eld
26647 \begin_inset Quotes erd
26651 \begin_inset Quotes erd
26657 All goto's are contained within the loop.
26660 No function calls within the loop.
26663 The loop control variable <sym> is not assigned any value within the loop
26666 The loop control variable does NOT participate in any arithmetic operation
26670 There are NO switch statements in the loop.
26673 Algebraic Simplifications
26676 SDCC does numerous algebraic simplifications, the following is a small sub-set
26677 of these optimizations.
26682 i = j + 0;\SpecialChar ~
26686 /* changed to: */\SpecialChar ~
26692 i /= 2;\SpecialChar ~
26699 /* changed to: */\SpecialChar ~
26705 i = j - j;\SpecialChar ~
26709 /* changed to: */\SpecialChar ~
26715 i = j / 1;\SpecialChar ~
26719 /* changed to: */\SpecialChar ~
26726 Note the subexpressions
26727 \begin_inset LatexCommand \index{Subexpression}
26731 given above are generally introduced by macro expansions or as a result
26732 of copy/constant propagation.
26735 'switch' Statements
26736 \begin_inset LatexCommand \label{sub:'switch'-Statements}
26741 \begin_inset LatexCommand \index{switch statement}
26748 SDCC can optimize switch statements to jump tables
26749 \begin_inset LatexCommand \index{jump tables}
26754 It makes the decision based on an estimate of the generated code size.
26755 SDCC is quite liberal in the requirements for jump table generation:
26758 The labels need not be in order, and the starting number need not be one
26759 or zero, the case labels are in numerical sequence or not too many case
26760 labels are missing.
26766 switch(i) {\SpecialChar ~
26797 case 4: ...\SpecialChar ~
26829 case 5: ...\SpecialChar ~
26861 case 3: ...\SpecialChar ~
26892 case 6: ...\SpecialChar ~
26924 case 7: ...\SpecialChar ~
26956 case 8: ...\SpecialChar ~
26988 case 9: ...\SpecialChar ~
27020 case 10: ...\SpecialChar ~
27051 case 11: ...\SpecialChar ~
27118 Both the above switch statements will be implemented using a jump-table.
27119 The example to the right side is slightly more efficient as the check for
27120 the lower boundary of the jump-table is not needed.
27124 The number of case labels is not larger than supported by the target architectur
27128 If the case labels are not in numerical sequence ('gaps' between cases)
27129 SDCC checks whether a jump table with additionally inserted dummy cases
27130 is still attractive.
27134 If the starting number is not zero and a check for the lower boundary of
27135 the jump-table can thus be eliminated SDCC might insert dummy cases 0,
27140 Switch statements which have large gaps in the numeric sequence or those
27141 that have too many case labels can be split into more than one switch statement
27142 for efficient code generation, e.g.:
27222 If the above switch statement is broken down into two switch statements
27312 then both the switch statements will be implemented using jump-tables whereas
27313 the unmodified switch statement will not be.
27316 There might be reasons which SDCC cannot know about to either favour or
27317 not favour jump tables.
27318 If the target system has to be as quick for the last switch case as for
27319 the first (pro jump table), or if the switch argument is known to be zero
27320 in the majority of the cases (contra jump table).
27323 The pragma nojtbound
27324 \begin_inset LatexCommand \index{\#pragma nojtbound}
27328 can be used to turn off checking the
27341 It has no effect if a default label is supplied.
27342 Use of this pragma is dangerous: if the switch
27343 \begin_inset LatexCommand \index{switch statement}
27347 argument is not matched by a case statement the processor will happily
27351 Bit-shifting Operations
27352 \begin_inset LatexCommand \index{Bit shifting}
27359 Bit shifting is one of the most frequently used operation in embedded programmin
27361 SDCC tries to implement bit-shift operations in the most efficient way
27377 generates the following code:
27394 In general SDCC will never setup a loop if the shift count is known.
27437 \begin_inset LatexCommand \index{Bit rotation}
27444 A special case of the bit-shift operation is bit rotation
27445 \begin_inset LatexCommand \index{rotating bits}
27449 , SDCC recognizes the following expression to be a left bit-rotation:
27459 char i;\SpecialChar ~
27470 /* unsigned is needed for rotation */
27475 i = ((i << 1) | (i >> 7));
27484 will generate the following code:
27503 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
27504 ns of this case will also be recognized as bit-rotation, i.e.:
27509 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
27512 Nibble and Byte Swapping
27515 Other special cases of the bit-shift operations are nibble or byte swapping
27516 \begin_inset LatexCommand \index{swapping nibbles/bytes}
27520 , SDCC recognizes the following expressions:
27543 i = ((i << 4) | (i >> 4));
27549 j = ((j << 8) | (j >> 8));
27552 and generates a swap instruction for the nibble swapping
27553 \begin_inset LatexCommand \index{Nibble swapping}
27557 or move instructions for the byte swapping
27558 \begin_inset LatexCommand \index{Byte swapping}
27564 \begin_inset Quotes sld
27568 \begin_inset Quotes srd
27571 example can be used to convert from little to big-endian or vice versa.
27572 If you want to change the endianness of a
27576 integer you have to cast to
27583 Note that SDCC stores numbers in little-endian
27589 Usually 8-bit processors don't care much about endianness.
27590 This is not the case for the standard 8051 which only has an instruction
27596 \begin_inset LatexCommand \index{DPTR}
27604 so little-endian is the more efficient byte order.
27608 \begin_inset LatexCommand \index{little-endian}
27613 \begin_inset LatexCommand \index{Endianness}
27618 lowest order first).
27622 \begin_inset LatexCommand \index{Highest Order Bit}
27627 \begin_inset LatexCommand \index{Any Order Bit}
27634 It is frequently required to obtain the highest order bit of an integral
27635 type (long, int, short or char types).
27636 Also obtaining any other order bit is not uncommon.
27637 SDCC recognizes the following expressions to yield the highest order bit
27638 and generates optimized code for it, e.g.:
27651 unsigned char hob1, aob1;
27655 bit hob2, hob3, aob2, aob3;
27664 hob1 = (gint >> 15) & 1;
27668 hob2 = (gint >> 15) & 1;
27672 hob3 = gint & 0x8000;
27676 aob1 = (gint >> 9) & 1;
27680 aob2 = (gint >> 8) & 1;
27684 aob3 = gint & 0x0800;
27694 will generate the following code:
27727 000A E5*01\SpecialChar ~
27754 000C 23\SpecialChar ~
27785 000D 54 01\SpecialChar ~
27812 000F F5*02\SpecialChar ~
27867 0011 E5*01\SpecialChar ~
27894 0013 33\SpecialChar ~
27924 0014 92*00\SpecialChar ~
27979 0016 E5*01\SpecialChar ~
28006 0018 33\SpecialChar ~
28036 0019 92*01\SpecialChar ~
28091 001B E5*01\SpecialChar ~
28118 001D 03\SpecialChar ~
28149 001E 54 01\SpecialChar ~
28176 0020 F5*03\SpecialChar ~
28231 0022 E5*01\SpecialChar ~
28258 0024 13\SpecialChar ~
28288 0025 92*02\SpecialChar ~
28343 0027 E5*01\SpecialChar ~
28370 0029 A2 E3\SpecialChar ~
28397 002B 92*03\SpecialChar ~
28425 Other variations of these cases however will
28430 They are standard C expressions, so I heartily recommend these be the only
28431 way to get the highest order bit, (it is portable).
28432 Of course it will be recognized even if it is embedded in other expressions,
28438 xyz = gint + ((gint >> 15) & 1);
28441 will still be recognized.
28445 \begin_inset LatexCommand \index{Higher Order Byte}
28449 / Higher Order Word
28450 \begin_inset LatexCommand \index{Higher Order Word}
28457 It is also frequently required to obtain a higher order byte or word of
28458 a larger integral type (long, int or short types).
28459 SDCC recognizes the following expressions to yield the higher order byte
28460 or word and generates optimized code for it, e.g.:
28467 unsigned long int glong;
28475 unsigned char hob1, hob2;
28479 unsigned int how1, how2;
28488 hob1 = (gint >> 8) & 0xFF;
28492 hob2 = glong >> 24;
28496 how1 = (glong >> 16) & 0xFFFF;
28510 will generate the following code:
28543 0037 85*01*06\SpecialChar ~
28565 _foo_hob1_1_1,(_gint + 1)
28595 003A 85*05*07\SpecialChar ~
28617 _foo_hob2_1_1,(_glong + 3)
28647 003D 85*04*08\SpecialChar ~
28669 _foo_how1_1_1,(_glong + 2)
28671 0040 85*05*09\SpecialChar ~
28693 (_foo_how1_1_1 + 1),(_glong + 3)
28695 0043 85*03*0A\SpecialChar ~
28717 _foo_how2_1_1,(_glong + 1)
28719 0046 85*04*0B\SpecialChar ~
28741 (_foo_how2_1_1 + 1),(_glong + 2)
28744 Again, variations of these cases may
28749 They are standard C expressions, so I heartily recommend these be the only
28750 way to get the higher order byte/word, (it is portable).
28751 Of course it will be recognized even if it is embedded in other expressions,
28757 xyz = gint + ((gint >> 8) & 0xFF);
28760 will still be recognized.
28764 \begin_inset LatexCommand \label{sub:Peephole-Optimizer}
28769 \begin_inset LatexCommand \index{Peephole optimizer}
28776 The compiler uses a rule based, pattern matching and re-writing mechanism
28777 for peep-hole optimization.
28782 a peep-hole optimizer by Christopher W.
28783 Fraser (cwfraser\SpecialChar ~
28786 A default set of rules are compiled into the compiler, additional rules
28787 may be added with the
28800 \begin_inset LatexCommand \index{-\/-peep-file}
28807 The rule language is best illustrated with examples.
28831 The above rule will change the following assembly
28832 \begin_inset LatexCommand \index{Assembler routines}
28854 Note: All occurrences of a
28858 (pattern variable) must denote the same string.
28859 With the above rule, the assembly sequence:
28869 will remain unmodified.
28873 Other special case optimizations may be added by the user (via
28889 some variants of the 8051 MCU
28890 \begin_inset LatexCommand \index{MCS51 variants}
28903 The following two rules will change all
28922 replace { lcall %1 } by { acall %1 }
28924 replace { ljmp %1 } by { ajmp %1 }
28929 inline-assembler code
28931 is also passed through the peep hole optimizer, thus the peephole optimizer
28932 can also be used as an assembly level macro expander.
28933 The rules themselves are MCU dependent whereas the rule language infra-structur
28934 e is MCU independent.
28935 Peephole optimization rules for other MCU can be easily programmed using
28940 The syntax for a rule is as follows:
28945 rule := replace [ restart ] '{' <assembly sequence> '
28983 <assembly sequence> '
29001 '}' [if <functionName> ] '
29006 <assembly sequence> := assembly instruction (each instruction including
29007 labels must be on a separate line).
29011 The optimizer will apply to the rules one by one from the top in the sequence
29012 of their appearance, it will terminate when all rules are exhausted.
29013 If the 'restart' option is specified, then the optimizer will start matching
29014 the rules again from the top, this option for a rule is expensive (performance)
29015 , it is intended to be used in situations where a transformation will trigger
29016 the same rule again.
29017 An example of this (not a good one, it has side effects) is the following
29040 Note that the replace pattern cannot be a blank, but can be a comment line.
29041 Without the 'restart' option only the innermost 'pop' 'push' pair would
29042 be eliminated, i.e.:
29072 the restart option the rule will be applied again to the resulting code
29073 and then all the pop-push pairs will be eliminated to yield:
29083 A conditional function can be attached to a rule.
29084 Attaching rules are somewhat more involved, let me illustrate this with
29111 The optimizer does a look-up of a function name table defined in function
29116 in the source file SDCCpeeph.c, with the name
29121 If it finds a corresponding entry the function is called.
29122 Note there can be no parameters specified for these functions, in this
29127 is crucial, since the function
29131 expects to find the label in that particular variable (the hash table containin
29132 g the variable bindings is passed as a parameter).
29133 If you want to code more such functions, take a close look at the function
29134 labelInRange and the calling mechanism in source file SDCCpeeph.c.
29135 Currently implemented are
29137 labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
29138 24bitMode, portIsDS390, 24bitModeAndPortDS390
29147 I know this whole thing is a little kludgey, but maybe some day we will
29148 have some better means.
29149 If you are looking at this file, you will see the default rules that are
29150 compiled into the compiler, you can add your own rules in the default set
29151 there if you get tired of specifying the -
29165 \begin_inset LatexCommand \index{ANSI-compliance}
29170 \begin_inset LatexCommand \label{sub:ANSI-Compliance}
29177 The latest publically available version of the standard
29179 ISO/IEC 9899 - Programming languages - C
29181 should be available at:
29182 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
29191 Deviations from the compliance:
29194 functions are not reentrant
29195 \begin_inset LatexCommand \index{reentrant}
29199 unless explicitly declared as such or the
29212 \begin_inset LatexCommand \index{-\/-stack-auto}
29218 command line option is specified.
29222 \begin_inset LatexCommand \index{struct}
29227 \begin_inset LatexCommand \index{union}
29231 cannot be assigned values directly, cannot be passed as function parameters
29232 or assigned to each other and cannot be a return value
29233 \begin_inset LatexCommand \index{return value}
29237 from a function, e.g.:
29263 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
29282 s parms) /* invalid in SDCC although allowed in ANSI */
29303 return rets; /* is invalid in SDCC although allowed in ANSI */
29309 initialization of structure arrays must be fully braced.
29315 struct s { char x } a[] = {1, 2};\SpecialChar ~
29320 /* invalid in SDCC */
29322 struct s { char x } a[] = {{1}, {2}}; /* OK */
29327 \begin_inset LatexCommand \index{long long (not supported)}
29332 \begin_inset LatexCommand \index{int (64 bit) (not supported)}
29340 \begin_inset LatexCommand \index{double (not supported)}
29344 ' precision floating point
29345 \begin_inset LatexCommand \index{Floating point support}
29353 \begin_inset LatexCommand \index{K\&R style}
29357 function declarations are NOT allowed.
29363 foo(i,j) /* this old style of function declarations */
29365 int i,j; /* are valid in ANSI but not valid in SDCC */
29380 Most enhancements in C99 are not supported, f.e.:
29388 \begin_inset LatexCommand \index{inline (not supported)}
29394 int increment (int a) { return a+1; } /* is invalid in SDCC although allowed
29400 can be used as a work around */
29408 i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
29412 Certain words that are valid identifiers in the standard may be reserved
29413 words in SDCC unless the
29426 \begin_inset LatexCommand \index{-\/-std-c89}
29441 \begin_inset LatexCommand \index{-\/-std-c99}
29447 command line options are used.
29448 These may include (depending on the selected processor): 'at', 'banked',
29449 'bit', 'code', 'critical', 'data', 'eeprom', 'far', 'flash', 'idata', 'interrup
29450 t', 'near', 'nonbanked', 'pdata', 'reentrant', 'sbit', 'sfr', 'shadowregs',
29451 'sram', 'using', 'wparam', 'xdata', '_overlay', '_asm', '_endasm', and
29453 Compliant equivalents of these keywords are always available in a form
29454 that begin with two underscores
29455 \begin_inset LatexCommand \index{\_\_ (prefix for extended keywords)}
29460 '__data' instead of 'data'.
29463 Cyclomatic Complexity
29464 \begin_inset LatexCommand \index{Cyclomatic complexity}
29471 Cyclomatic complexity of a function is defined as the number of independent
29472 paths the program can take during execution of the function.
29473 This is an important number since it defines the number test cases you
29474 have to generate to validate the function.
29475 The accepted industry standard for complexity number is 10, if the cyclomatic
29476 complexity reported by SDCC exceeds 10 you should think about simplification
29477 of the function logic.
29478 Note that the complexity level is not related to the number of lines of
29479 code in a function.
29480 Large functions can have low complexity, and small functions can have large
29486 SDCC uses the following formula to compute the complexity:
29491 complexity = (number of edges in control flow graph) - (number of nodes
29492 in control flow graph) + 2;
29496 Having said that the industry standard is 10, you should be aware that in
29497 some cases it be may unavoidable to have a complexity level of less than
29499 For example if you have switch statement with more than 10 case labels,
29500 each case label adds one to the complexity level.
29501 The complexity level is by no means an absolute measure of the algorithmic
29502 complexity of the function, it does however provide a good starting point
29503 for which functions you might look at for further optimization.
29506 Retargetting for other Processors
29509 The issues for retargetting the compiler are far too numerous to be covered
29511 What follows is a brief description of each of the seven phases of the
29512 compiler and its MCU dependency.
29515 Parsing the source and building the annotated parse tree.
29516 This phase is largely MCU independent (except for the language extensions).
29517 Syntax & semantic checks are also done in this phase, along with some initial
29518 optimizations like back patching labels and the pattern matching optimizations
29519 like bit-rotation etc.
29522 The second phase involves generating an intermediate code which can be easy
29523 manipulated during the later phases.
29524 This phase is entirely MCU independent.
29525 The intermediate code generation assumes the target machine has unlimited
29526 number of registers, and designates them with the name iTemp.
29527 The compiler can be made to dump a human readable form of the code generated
29541 This phase does the bulk of the standard optimizations and is also MCU independe
29543 This phase can be broken down into several sub-phases:
29547 Break down intermediate code (iCode) into basic blocks.
29549 Do control flow & data flow analysis on the basic blocks.
29551 Do local common subexpression elimination, then global subexpression elimination
29553 Dead code elimination
29557 If loop optimizations caused any changes then do 'global subexpression eliminati
29558 on' and 'dead code elimination' again.
29561 This phase determines the live-ranges; by live range I mean those iTemp
29562 variables defined by the compiler that still survive after all the optimization
29564 Live range analysis
29565 \begin_inset LatexCommand \index{Live range analysis}
29569 is essential for register allocation, since these computation determines
29570 which of these iTemps will be assigned to registers, and for how long.
29573 Phase five is register allocation.
29574 There are two parts to this process.
29578 The first part I call 'register packing' (for lack of a better term).
29579 In this case several MCU specific expression folding is done to reduce
29584 The second part is more MCU independent and deals with allocating registers
29585 to the remaining live ranges.
29586 A lot of MCU specific code does creep into this phase because of the limited
29587 number of index registers available in the 8051.
29590 The Code generation phase is (unhappily), entirely MCU dependent and very
29591 little (if any at all) of this code can be reused for other MCU.
29592 However the scheme for allocating a homogenized assembler operand for each
29593 iCode operand may be reused.
29596 As mentioned in the optimization section the peep-hole optimizer is rule
29597 based system, which can reprogrammed for other MCUs.
29601 \begin_inset LatexCommand \index{Compiler internals}
29608 The anatomy of the compiler
29609 \begin_inset LatexCommand \label{sub:The-anatomy-of}
29618 This is an excerpt from an article published in Circuit Cellar Magazine
29624 It's a little outdated (the compiler is much more efficient now and user/develo
29625 per friendly), but pretty well exposes the guts of it all.
29631 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
29632 It is fairly easy to retarget for other 8-bit MCU.
29633 Here we take a look at some of the internals of the compiler.
29638 \begin_inset LatexCommand \index{Parsing}
29645 Parsing the input source file and creating an AST (Annotated Syntax Tree
29646 \begin_inset LatexCommand \index{Annotated syntax tree}
29651 This phase also involves propagating types (annotating each node of the
29652 parse tree with type information) and semantic analysis.
29653 There are some MCU specific parsing rules.
29654 For example the storage classes, the extended storage classes are MCU specific
29655 while there may be a xdata storage class for 8051 there is no such storage
29656 class for z80 or Atmel AVR.
29657 SDCC allows MCU specific storage class extensions, i.e.
29658 xdata will be treated as a storage class specifier when parsing 8051 C
29659 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
29664 \begin_inset LatexCommand \index{iCode}
29671 Intermediate code generation.
29672 In this phase the AST is broken down into three-operand form (iCode).
29673 These three operand forms are represented as doubly linked lists.
29674 ICode is the term given to the intermediate form generated by the compiler.
29675 ICode example section shows some examples of iCode generated for some simple
29676 C source functions.
29680 \begin_inset LatexCommand \index{Optimizations}
29687 Bulk of the target independent optimizations is performed in this phase.
29688 The optimizations include constant propagation, common sub-expression eliminati
29689 on, loop invariant code movement, strength reduction of loop induction variables
29690 and dead-code elimination.
29693 Live range analysis
29694 \begin_inset LatexCommand \index{Live range analysis}
29701 During intermediate code generation phase, the compiler assumes the target
29702 machine has infinite number of registers and generates a lot of temporary
29704 The live range computation determines the lifetime of each of these compiler-ge
29705 nerated temporaries.
29706 A picture speaks a thousand words.
29707 ICode example sections show the live range annotations for each of the
29709 It is important to note here, each iCode is assigned a number in the order
29710 of its execution in the function.
29711 The live ranges are computed in terms of these numbers.
29712 The from number is the number of the iCode which first defines the operand
29713 and the to number signifies the iCode which uses this operand last.
29716 Register Allocation
29717 \begin_inset LatexCommand \index{Register allocation}
29724 The register allocation determines the type and number of registers needed
29726 In most MCUs only a few registers can be used for indirect addressing.
29727 In case of 8051 for example the registers R0 & R1 can be used to indirectly
29728 address the internal ram and DPTR to indirectly address the external ram.
29729 The compiler will try to allocate the appropriate register to pointer variables
29731 ICode example section shows the operands annotated with the registers assigned
29733 The compiler will try to keep operands in registers as much as possible;
29734 there are several schemes the compiler uses to do achieve this.
29735 When the compiler runs out of registers the compiler will check to see
29736 if there are any live operands which is not used or defined in the current
29737 basic block being processed, if there are any found then it will push that
29738 operand and use the registers in this block, the operand will then be popped
29739 at the end of the basic block.
29743 There are other MCU specific considerations in this phase.
29744 Some MCUs have an accumulator; very short-lived operands could be assigned
29745 to the accumulator instead of a general-purpose register.
29751 Figure II gives a table of iCode operations supported by the compiler.
29752 The code generation involves translating these operations into corresponding
29753 assembly code for the processor.
29754 This sounds overly simple but that is the essence of code generation.
29755 Some of the iCode operations are generated on a MCU specific manner for
29756 example, the z80 port does not use registers to pass parameters so the
29757 SEND and RECV iCode operations will not be generated, and it also does
29758 not support JUMPTABLES.
29765 <Where is Figure II?>
29768 In the original article Figure II was announced to be downloadable on
29773 Unfortunately it never seemed to have shown up there, so: where is Figure
29778 \begin_inset LatexCommand \index{iCode}
29785 This section shows some details of iCode.
29786 The example C code does not do anything useful; it is used as an example
29787 to illustrate the intermediate code generated by the compiler.
29799 /* This function does nothing useful.
29806 for the purpose of explaining iCode */
29809 short function (data int *x)
29817 short i=10; \SpecialChar ~
29819 /* dead initialization eliminated */
29824 short sum=10; /* dead initialization eliminated */
29837 while (*x) *x++ = *p++;
29851 /* compiler detects i,j to be induction variables */
29855 for (i = 0, j = 10 ; i < 10 ; i++, j
29881 mul += i * 3; \SpecialChar ~
29883 /* this multiplication remains */
29889 gint += j * 3;\SpecialChar ~
29891 /* this multiplication changed to addition */
29905 In addition to the operands each iCode contains information about the filename
29906 and line it corresponds to in the source file.
29907 The first field in the listing should be interpreted as follows:
29912 Filename(linenumber: iCode Execution sequence number : ICode hash table
29913 key : loop depth of the iCode).
29918 Then follows the human readable form of the ICode operation.
29919 Each operand of this triplet form can be of three basic types a) compiler
29920 generated temporary b) user defined variable c) a constant value.
29921 Note that local variables and parameters are replaced by compiler generated
29924 \begin_inset LatexCommand \index{Live range analysis}
29928 are computed only for temporaries (i.e.
29929 live ranges are not computed for global variables).
29931 \begin_inset LatexCommand \index{Register allocation}
29935 are allocated for temporaries only.
29936 Operands are formatted in the following manner:
29941 Operand Name [lr live-from : live-to ] { type information } [ registers
29947 As mentioned earlier the live ranges are computed in terms of the execution
29948 sequence number of the iCodes, for example
29950 the iTemp0 is live from (i.e.
29951 first defined in iCode with execution sequence number 3, and is last used
29952 in the iCode with sequence number 5).
29953 For induction variables such as iTemp21 the live range computation extends
29954 the lifetime from the start to the end of the loop.
29956 The register allocator used the live range information to allocate registers,
29957 the same registers may be used for different temporaries if their live
29958 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
29959 iTemp17 since their live ranges do not overlap.
29960 In addition the allocator also takes into consideration the type and usage
29961 of a temporary, for example itemp6 is a pointer to near space and is used
29962 as to fetch data from (i.e.
29963 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
29964 Some short lived temporaries are allocated to special registers which have
29965 meaning to the code generator e.g.
29966 iTemp13 is allocated to a pseudo register CC which tells the back end that
29967 the temporary is used only for a conditional jump the code generation makes
29968 use of this information to optimize a compare and jump ICode.
29970 There are several loop optimizations
29971 \begin_inset LatexCommand \index{Loop optimization}
29975 performed by the compiler.
29976 It can detect induction variables iTemp21(i) and iTemp23(j).
29977 Also note the compiler does selective strength reduction
29978 \begin_inset LatexCommand \index{Strength reduction}
29983 the multiplication of an induction variable in line 18 (gint = j * 3) is
29984 changed to addition, a new temporary iTemp17 is allocated and assigned
29985 a initial value, a constant 3 is then added for each iteration of the loop.
29986 The compiler does not change the multiplication
29987 \begin_inset LatexCommand \index{Multiplication}
29991 in line 17 however since the processor does support an 8 * 8 bit multiplication.
29993 Note the dead code elimination
29994 \begin_inset LatexCommand \index{Dead-code elimination}
29998 optimization eliminated the dead assignments in line 7 & 8 to I and sum
30006 Sample.c (5:1:0:0) _entry($9) :
30011 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
30016 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
30021 Sample.c(11:4:53:0) preHeaderLbl0($11) :
30026 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
30032 Sample.c(11:6:5:1) _whilecontinue_0($1) :
30037 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
30043 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
30048 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
30054 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
30060 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
30066 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
30072 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
30073 * int}[r0] + 0x2 {short}
30078 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
30083 Sample.c(11:17:21:0)_whilebreak_0($3) :
30088 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
30093 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
30098 Sample.c(15:20:54:0)preHeaderLbl1($13) :
30103 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
30108 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
30113 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
30118 Sample.c(15:24:26:1)_forcond_0($4) :
30123 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
30129 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
30134 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
30135 + ITemp21 [lr21:38]{short}[r4]
30140 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
30146 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
30147 + iTemp15 [lr29:30]{short}[r1]
30152 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
30158 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
30164 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
30170 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
30176 Sample.c(19:38:47:1) goto _forcond_0($4)
30181 Sample.c(19:39:48:0)_forbreak_0($7) :
30186 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
30187 + ITemp11 [lr19:40]{short}[r3]
30192 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
30197 Sample.c(20:42:51:0)_return($8) :
30202 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
30208 Finally the code generated for this function:
30249 ; ----------------------------------------------
30254 ; function function
30259 ; ----------------------------------------------
30269 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
30281 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
30293 ;_whilecontinue_0($1) :
30303 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
30308 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
30367 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
30386 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
30433 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
30473 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
30499 ; iTemp6 [lr5:16]{_near * int}[r0] =
30504 ; iTemp6 [lr5:16]{_near * int}[r0] +
30521 ; goto _whilecontinue_0($1)
30533 ; _whilebreak_0($3) :
30543 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
30555 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
30567 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
30579 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
30598 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
30627 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
30632 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
30677 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
30682 ; iTemp21 [lr21:38]{short}[r4]
30708 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
30741 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
30746 ; iTemp15 [lr29:30]{short}[r1]
30765 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
30812 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
30859 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
30871 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
30885 cjne r5,#0xff,00104$
30897 ; goto _forcond_0($4)
30909 ; _forbreak_0($7) :
30919 ; ret iTemp24 [lr40:41]{short}
30962 A few words about basic block successors, predecessors and dominators
30965 Successors are basic blocks
30966 \begin_inset LatexCommand \index{Basic blocks}
30970 that might execute after this basic block.
30972 Predecessors are basic blocks that might execute before reaching this basic
30975 Dominators are basic blocks that WILL execute before reaching this basic
31009 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
31012 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
31015 c) domVect of [BB4] = BB1 ...
31016 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
31024 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
31034 Thanks to all the other volunteer developers who have helped with coding,
31035 testing, web-page creation, distribution sets, etc.
31036 You know who you are :-)
31044 Also thanks to Sourceforge
31045 \begin_inset LatexCommand \url{http://www.sf.net}
31049 which has hosted the project since 1999 and donates significant download
31050 bandwidth and probably more than
31058 CPU cycles per day.
31066 more than 10^13 is an estimate: on my Athlon 2800+ it takes about (0.5+6.5+20)
31067 minutes for (configure+make+regression test), and there is (i386, amd64,
31068 alpha, ppc64, (mingw32), sparc, macosx).
31075 This document was initially written by Sandeep Dutta
31078 All product names mentioned herein may be trademarks
31079 \begin_inset LatexCommand \index{Trademarks}
31083 of their respective companies.
31090 To avoid confusion, the installation and building options for SDCC itself
31091 (chapter 2) are not part of the index.
31095 \begin_inset LatexCommand \printindex{}
projects / fw / sdcc / blob