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">
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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">
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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">
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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
1063 \labelwidthstring 00.00.0000
1075 -datarootdir see table below
1079 \labelwidthstring 00.00.0000
1083 docdir environment variable, see table below
1085 \labelwidthstring 00.00.0000
1089 include_dir_suffix environment variable, see table below
1091 \labelwidthstring 00.00.0000
1095 lib_dir_suffix environment variable, see table below
1097 \labelwidthstring 00.00.0000
1101 sdccconf_h_dir_separator environment variable, either / or
1106 This character will only be used in sdccconf.h; don't forget it's a C-header,
1107 therefore a double-backslash is needed there.
1111 \labelwidthstring 00.00.0000
1123 -disable-mcs51-port Excludes the Intel mcs51 port
1125 \labelwidthstring 00.00.0000
1137 -disable-gbz80-port Excludes the Gameboy gbz80 port
1139 \labelwidthstring 00.00.0000
1151 -disable-z80-port Excludes the z80 port
1153 \labelwidthstring 00.00.0000
1165 -disable-avr-port Excludes the AVR port
1167 \labelwidthstring 00.00.0000
1179 -disable-ds390-port Excludes the DS390 port
1181 \labelwidthstring 00.00.0000
1193 -disable-hc08-port Excludes the HC08 port
1195 \labelwidthstring 00.00.0000
1207 -disable-pic-port Excludes the PIC port
1209 \labelwidthstring 00.00.0000
1221 -disable-xa51-port Excludes the XA51 port
1223 \labelwidthstring 00.00.0000
1235 -disable-ucsim Disables configuring and building of ucsim
1237 \labelwidthstring 00.00.0000
1249 -disable-device-lib Disables automatically building device libraries
1251 \labelwidthstring 00.00.0000
1263 -disable-packihx Disables building packihx
1267 \labelwidthstring 00.00.0000
1279 -enable-doc Build pdf, html and txt files from the lyx sources
1281 \labelwidthstring 00.00.0000
1293 -enable-libgc Use the Bohem memory allocator.
1294 Lower runtime footprint.
1297 Furthermore the environment variables CC, CFLAGS, ...
1298 the tools and their arguments can be influenced.
1299 Please see `configure -
1309 -help` and the man/info pages of `configure` for details.
1313 The names of the standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB,
1314 STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
1315 NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
1316 At the moment it's not possible to change the default settings (it was
1317 simply never required).
1321 These configure options are compiled into the binaries, and can only be
1322 changed by rerunning 'configure' and recompiling SDCC.
1323 The configure options are written in
1327 to distinguish them from run time environment variables (see section search
1333 \begin_inset Quotes sld
1337 \begin_inset Quotes srd
1340 are used by the SDCC team to build the official Win32 binaries.
1341 The SDCC team uses Mingw32 to build the official Windows binaries, because
1348 a gcc compiler and last but not least
1351 the binaries can be built by cross compiling on Sourceforge's compile farm.
1354 See the examples, how to pass the Win32 settings to 'configure'.
1355 The other Win32 builds using Borland, VC or whatever don't use 'configure',
1356 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
1367 \begin_inset Tabular
1368 <lyxtabular version="3" rows="9" columns="3">
1370 <column alignment="block" valignment="top" leftline="true" width="0in">
1371 <column alignment="block" valignment="top" leftline="true" width="0in">
1372 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1373 <row topline="true" bottomline="true">
1374 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1382 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1390 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1399 <row topline="true">
1400 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1410 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1418 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
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1461 <row topline="true">
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1499 <row topline="true">
1500 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1510 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1520 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1531 <row topline="true">
1532 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1542 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1554 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1565 <row topline="true">
1566 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1576 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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1603 <row topline="true">
1604 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1614 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1622 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
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1632 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1642 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1650 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1668 'configure' also computes relative paths.
1669 This is needed for full relocatability of a binary package and to complete
1670 search paths (see section search paths below):
1676 \begin_inset Tabular
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1680 <column alignment="block" valignment="top" leftline="true" width="0in">
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1719 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
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1736 <row bottomline="true">
1737 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1747 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1755 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1764 <row bottomline="true">
1765 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1775 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1783 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1816 \begin_inset Quotes srd
1820 \begin_inset Quotes srd
1834 \begin_inset Quotes srd
1838 \begin_inset Quotes srd
1866 To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
1875 \begin_inset Quotes srd
1878 i586-mingw32msvc-gcc
1879 \begin_inset Quotes srd
1883 \begin_inset Quotes srd
1886 i586-mingw32msvc-g++
1887 \begin_inset Quotes srd
1895 \begin_inset Quotes srd
1898 i586-mingw32msvc-ranlib
1899 \begin_inset Quotes srd
1907 \begin_inset Quotes srd
1910 i586-mingw32msvc-strip
1911 \begin_inset Quotes srd
1929 \begin_inset Quotes srd
1933 \begin_inset Quotes srd
1951 \begin_inset Quotes srd
1955 \begin_inset Quotes srd
1963 \begin_inset Quotes srd
1969 \begin_inset Quotes srd
1977 \begin_inset Quotes srd
1981 \begin_inset Quotes srd
1989 \begin_inset Quotes srd
1993 \begin_inset Quotes srd
2000 sdccconf_h_dir_separator=
2001 \begin_inset Quotes srd
2013 \begin_inset Quotes srd
2044 -host=i586-mingw32msvc
2058 -build=unknown-unknown-linux-gnu
2062 \begin_inset Quotes sld
2066 \begin_inset Quotes srd
2069 compile on Cygwin for Mingw32 (see also sdcc/support/scripts/sdcc_cygwin_mingw32
2088 \begin_inset Quotes srd
2092 \begin_inset Quotes srd
2110 \begin_inset Quotes srd
2114 \begin_inset Quotes srd
2122 \begin_inset Quotes srd
2128 \begin_inset Quotes srd
2136 \begin_inset Quotes srd
2140 \begin_inset Quotes srd
2148 \begin_inset Quotes srd
2152 \begin_inset Quotes srd
2159 sdccconf_h_dir_separator=
2160 \begin_inset Quotes srd
2172 \begin_inset Quotes srd
2180 \begin_inset Quotes srd
2184 \begin_inset Quotes srd
2192 \begin_inset Quotes srd
2196 \begin_inset Quotes srd
2202 'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
2213 -C' turns on caching, which gives a little bit extra speed.
2214 However if options are changed, it can be necessary to delete the config.cache
2219 \begin_inset LatexCommand \label{sub:Install-paths}
2224 \begin_inset LatexCommand \index{Install paths}
2230 \added_space_top medskip \align center
2232 \begin_inset Tabular
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2235 <column alignment="left" valignment="top" leftline="true" width="0">
2236 <column alignment="left" valignment="top" leftline="true" width="0">
2237 <column alignment="left" valignment="top" leftline="true" width="0">
2238 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
2239 <row topline="true" bottomline="true">
2240 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2250 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2260 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2270 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2281 <row topline="true">
2282 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2290 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2300 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2308 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
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2322 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2330 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2337 $DATADIR/ $INCLUDE_DIR_SUFFIX
2340 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2345 /usr/local/share/sdcc/include
2348 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2361 <row topline="true">
2362 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2370 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2377 $DATADIR/$LIB_DIR_SUFFIX
2380 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2385 /usr/local/share/sdcc/lib
2388 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2401 <row topline="true" bottomline="true">
2402 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2410 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2420 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2425 /usr/local/share/sdcc/doc
2428 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2450 *compiler, preprocessor, assembler, and linker
2456 is auto-appended by the compiler, e.g.
2457 small, large, z80, ds390 etc
2460 The install paths can still be changed during `make install` with e.g.:
2463 make install prefix=$(HOME)/local/sdcc
2466 Of course this doesn't change the search paths compiled into the binaries.
2470 Moreover the install path can be changed by defining DESTDIR
2471 \begin_inset LatexCommand \index{DESTDIR}
2478 make install DESTDIR=$(HOME)/sdcc.rpm/
2481 Please note that DESTDIR must have a trailing slash!
2485 \begin_inset LatexCommand \label{sub:Search-Paths}
2490 \begin_inset LatexCommand \index{Search path}
2497 Some search paths or parts of them are determined by configure variables
2502 , see section above).
2503 Further search paths are determined by environment variables during runtime.
2506 The paths searched when running the compiler are as follows (the first catch
2512 Binary files (preprocessor, assembler and linker)
2518 \begin_inset Tabular
2519 <lyxtabular version="3" rows="4" columns="3">
2521 <column alignment="block" valignment="top" leftline="true" width="0in">
2522 <column alignment="block" valignment="top" leftline="true" width="0in">
2523 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2524 <row topline="true" bottomline="true">
2525 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2533 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2541 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2550 <row topline="true">
2551 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2561 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2569 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2580 <row topline="true">
2581 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2586 Path of argv[0] (if available)
2589 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2597 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2606 <row topline="true" bottomline="true">
2607 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2615 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2623 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2648 \begin_inset Tabular
2649 <lyxtabular version="3" rows="6" columns="3">
2651 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2652 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2653 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2654 <row topline="true" bottomline="true">
2655 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2663 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2671 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2680 <row topline="true">
2681 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2699 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2717 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2736 <row topline="true">
2737 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2745 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2753 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2762 <row topline="true">
2763 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2777 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2789 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2800 <row topline="true">
2801 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2819 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2869 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2882 <row topline="true" bottomline="true">
2883 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2899 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2904 /usr/local/share/sdcc/
2909 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2937 -nostdinc disables the last two search paths.
2947 With the exception of
2948 \begin_inset Quotes sld
2962 \begin_inset Quotes srd
2969 is auto-appended by the compiler (e.g.
2970 small, large, z80, ds390 etc.).
2977 \begin_inset Tabular
2978 <lyxtabular version="3" rows="6" columns="3">
2980 <column alignment="block" valignment="top" leftline="true" width="1.7in">
2981 <column alignment="block" valignment="top" leftline="true" width="1.2in">
2982 <column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
2983 <row topline="true" bottomline="true">
2984 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2992 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3000 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3009 <row topline="true">
3010 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3028 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3046 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3065 <row topline="true">
3066 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3078 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3090 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3105 <row topline="true">
3106 <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">
3134 <cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3151 <row topline="true">
3152 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3167 $LIB_DIR_SUFFIX/<model>
3170 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
3223 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3279 <row topline="true" bottomline="true">
3280 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3289 $LIB_DIR_SUFFIX/<model>
3292 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3297 /usr/local/share/sdcc/
3304 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3322 Don't delete any of the stray spaces in the table above without checking
3323 the HTML output (last line)!
3339 -nostdlib disables the last two search paths.
3343 \begin_inset LatexCommand \index{Building SDCC}
3350 Building SDCC on Linux
3351 \begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}
3360 Download the source package
3362 either from the SDCC Subversion repository or from the nightly snapshots
3364 , it will be named something like sdcc
3375 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
3384 Bring up a command line terminal, such as xterm.
3389 Unpack the file using a command like:
3392 "tar -xvzf sdcc.src.tar.gz
3397 , this will create a sub-directory called sdcc with all of the sources.
3400 Change directory into the main SDCC directory, for example type:
3417 This configures the package for compilation on your system.
3433 All of the source packages will compile, this can take a while.
3449 This copies the binary executables, the include files, the libraries and
3450 the documentation to the install directories.
3451 Proceed with section
3452 \begin_inset LatexCommand \ref{sec:Testing-the-SDCC}
3459 Building SDCC on OSX 2.x
3462 Follow the instruction for Linux.
3466 On OSX 2.x it was reported, that the default gcc (version 3.1 20020420 (prerelease
3467 )) fails to compile SDCC.
3468 Fortunately there's also gcc 2.9.x installed, which works fine.
3469 This compiler can be selected by running 'configure' with:
3472 ./configure CC=gcc2 CXX=g++2
3475 Cross compiling SDCC on Linux for Windows
3478 With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
3479 See section 'Configure Options'.
3482 Building SDCC using Cygwin and Mingw32
3485 For building and installing a Cygwin executable follow the instructions
3491 \begin_inset Quotes sld
3495 \begin_inset Quotes srd
3498 Win32-binary can be built, which will not need the Cygwin-DLL.
3499 For the necessary 'configure' options see section 'configure options' or
3500 the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
3504 In order to install Cygwin on Windows download setup.exe from
3505 \begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}
3511 \begin_inset Quotes sld
3514 default text file type
3515 \begin_inset Quotes srd
3519 \begin_inset Quotes sld
3523 \begin_inset Quotes srd
3526 and download/install at least the following packages.
3527 Some packages are selected by default, others will be automatically selected
3528 because of dependencies with the manually selected packages.
3529 Never deselect these packages!
3538 gcc ; version 3.x is fine, no need to use the old 2.9x
3541 binutils ; selected with gcc
3547 rxvt ; a nice console, which makes life much easier under windoze (see below)
3550 man ; not really needed for building SDCC, but you'll miss it sooner or
3554 less ; not really needed for building SDCC, but you'll miss it sooner or
3558 svn ; only if you use Subversion access
3561 If you want to develop something you'll need:
3564 python ; for the regression tests
3567 gdb ; the gnu debugger, together with the nice GUI
3568 \begin_inset Quotes sld
3572 \begin_inset Quotes srd
3578 openssh ; to access the CF or commit changes
3581 autoconf and autoconf-devel ; if you want to fight with 'configure', don't
3582 use autoconf-stable!
3585 rxvt is a nice console with history.
3586 Replace in your cygwin.bat the line
3605 rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
3608 -bg black -fg white -geometry 100x65 -e bash -
3621 Text selected with the mouse is automatically copied to the clipboard, pasting
3622 works with shift-insert.
3626 The other good tip is to make sure you have no //c/-style paths anywhere,
3627 use /cygdrive/c/ instead.
3628 Using // invokes a network lookup which is very slow.
3630 \begin_inset Quotes sld
3634 \begin_inset Quotes srd
3637 is too long, you can change it with e.g.
3643 SDCC sources use the unix line ending LF.
3644 Life is much easier, if you store the source tree on a drive which is mounted
3646 And use an editor which can handle LF-only line endings.
3647 Make sure not to commit files with windows line endings.
3648 The tabulator spacing
3649 \begin_inset LatexCommand \index{tabulator spacing (8 columns)}
3653 used in the project is 8.
3654 Although a tabulator spacing of 8 is a sensible choice for programmers
3655 (it's a power of 2 and allows to display 8/16 bit signed variables without
3656 loosing columns) the plan is to move towards using only spaces in the source.
3659 Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
3664 Download the source package
3666 either from the SDCC Subversion repository or from the
3667 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
3673 , it will be named something like sdcc
3680 SDCC is distributed with all the projects, workspaces, and files you need
3681 to build it using Visual C++ 6.0/NET (except for SDCDB and ucSim).
3682 The workspace name is 'sdcc.dsw'.
3683 Please note that as it is now, all the executables are created in a folder
3687 Once built you need to copy the executables from sdcc
3691 bin before running SDCC.
3696 WARNING: Visual studio is very picky with line terminations; it expects
3697 the 0x0d, 0x0a DOS style line endings, not the 0x0a Unix style line endings.
3698 When using the Subversion repository it's easiest to configure the svn
3699 client to convert automatically for you.
3700 If however you are getting a message such as "This makefile was not generated
3701 by Developer Studio etc.
3703 \begin_inset Quotes srd
3706 when opening the sdcc.dsw workspace or any of the *.dsp projects, then you
3707 need to convert the Unix style line endings to DOS style line endings.
3708 To do so you can use the
3709 \begin_inset Quotes sld
3713 \begin_inset Quotes srd
3716 utility freely available on the internet.
3717 Doug Hawkins reported in the sdcc-user list that this works:
3725 SDCC> unix2dos sdcc.dsw
3731 SDCC> for /R %I in (*.dsp) do @unix2dos "%I"
3735 In order to build SDCC with MSVC you need win32 executables of bison.exe,
3736 flex.exe, and gawk.exe.
3737 One good place to get them is
3738 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
3746 Download the file UnxUtils
3747 \begin_inset LatexCommand \index{UnxUtils}
3752 Now you have to install the utilities and setup MSVC so it can locate the
3754 Here there are two alternatives (choose one!):
3761 a) Extract UnxUtils.zip to your C:
3763 hard disk PRESERVING the original paths, otherwise bison won't work.
3764 (If you are using WinZip make certain that 'Use folder names' is selected)
3768 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3769 in 'Show directories for:' select 'Executable files', and in the directories
3770 window add a new path: 'C:
3780 (As a side effect, you get a bunch of Unix utilities that could be useful,
3781 such as diff and patch.)
3788 This one avoids extracting a bunch of files you may not use, but requires
3793 a) Create a directory were to put the tools needed, or use a directory already
3801 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
3802 to such directory WITHOUT preserving the original paths.
3803 (If you are using WinZip make certain that 'Use folder names' is not selected)
3807 c) Rename bison.exe to '_bison.exe'.
3811 d) Create a batch file 'bison.bat' in 'C:
3815 ' and add these lines:
3835 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
3839 Steps 'c' and 'd' are needed because bison requires by default that the
3840 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
3841 '/usr/local/share/' I think.
3842 So it is necessary to tell bison where those files are located if they
3843 are not in such directory.
3844 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
3848 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3849 in 'Show directories for:' select 'Executable files', and in the directories
3850 window add a new path: 'c:
3853 Note that you can use any other path instead of 'c:
3855 util', even the path where the Visual C++ tools are, probably: 'C:
3859 Microsoft Visual Studio
3864 So you don't have to execute step 'e' :)
3868 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
3869 the executables from sdcc
3873 bin, and you can compile using SDCC.
3876 Building SDCC Using Borland
3879 From the sdcc directory, run the command "make -f Makefile.bcc".
3880 This should regenerate all the .exe files in the bin directory except for
3884 If you modify any source files and need to rebuild, be aware that the dependenci
3885 es may not be correctly calculated.
3886 The safest option is to delete all .obj files and run the build again.
3887 From a Cygwin BASH prompt, this can easily be done with the command (be
3888 sure you are in the sdcc directory):
3898 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
3900 ) -print -exec rm {}
3909 or on Windows NT/2000/XP from the command prompt with the command:
3916 del /s *.obj *.lib *.rul
3919 from the sdcc directory.
3922 Windows Install Using a ZIP Package
3925 Download the binary zip package from
3926 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3930 and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
3931 This should unpack to a group of sub-directories.
3932 An example directory structure after unpacking the mingw32 package is:
3937 bin for the executables, c:
3945 lib for the include and libraries.
3948 Adjust your environment variable PATH to include the location of the bin
3949 directory or start sdcc using the full path.
3952 Windows Install Using the Setup Program
3953 \begin_inset LatexCommand \label{sub:Windows-Install}
3960 Download the setup program
3962 sdcc-x.y.z-setup.exe
3964 for an official release from
3967 \begin_inset LatexCommand \url{http://sf.net/project/showfiles.php?group_id=599}
3971 or a setup program for one of the snapshots
3973 sdcc-yyyymmdd-xxxx-setup.exe
3976 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3981 A windows typical installer will guide you through the installation process.
3985 \begin_inset LatexCommand \index{VPATH}
3992 SDCC supports the VPATH feature provided by configure and make.
3993 It allows to separate the source and build trees.
4025 tar -xzf sdcc.src.tar.gz\SpecialChar ~
4026 # extract source to directory sdcc
4031 mkdir sdcc.build\SpecialChar ~
4040 # put output in sdcc.build
4050 ../sdcc/configure\SpecialChar ~
4058 # configure is doing all the magic!
4070 will create the directory tree will all the necessary Makefiles in ~/sdcc.build.
4071 It automagically computes the variables srcdir, top_srcdir and top_buildir
4077 the generated files will be in ~/sdcc.build, while the source files stay
4080 This is not only usefull for building different binaries, e.g.
4081 when cross compiling.
4082 It also gives you a much better overview in the source tree when all the
4083 generated files are not scattered between the source files.
4084 And the best thing is: if you want to change a file you can leave the original
4085 file untouched in the source directory.
4086 Simply copy it to the build directory, edit it, enter `make clean`, `rm
4087 Makefile.dep` and `make`.
4092 will do the rest for you!
4095 Building the Documentation
4108 -enable-doc to the configure arguments to build the documentation together
4109 with all the other stuff.
4110 You will need several tools (LyX, LaTeX, LaTeX2HTML, pdflatex, dvipdf,
4111 dvips and makeindex) to get the job done.
4112 Another possibility is to change to the doc directory and to type
4116 \begin_inset Quotes srd
4120 \begin_inset Quotes srd
4127 You're invited to make changes and additions to this manual (sdcc/doc/sdccman.ly
4130 \begin_inset LatexCommand \url{http://www.lyx.org}
4134 as editor is straightforward.
4135 Prebuilt documentation in html and pdf format is available from
4136 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
4143 Reading the Documentation
4144 \begin_inset LatexCommand \index{Documentation}
4151 Currently reading the document in pdf format is recommended, as for unknown
4152 reason the hyperlinks are working there whereas in the html version they
4159 If you should know why please drop us a note
4165 You'll find the pdf version
4166 \begin_inset LatexCommand \index{PDF version of this document}
4171 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.pdf}
4179 \begin_inset LatexCommand \index{HTML version of this document}
4184 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.html/index.html}
4190 This documentation is in some aspects different from a commercial documentation:
4194 It tries to document SDCC for several processor architectures in one document
4195 (commercially these probably would be separate documents/products).
4197 \begin_inset LatexCommand \index{Status of documentation}
4201 currently matches SDCC for mcs51 and DS390 best and does give too few informati
4203 Z80, PIC14, PIC16 and HC08.
4206 There are many references pointing away from this documentation.
4207 Don't let this distract you.
4209 was a reference like
4210 \begin_inset LatexCommand \url{http://www.opencores.org}
4214 together with a statement
4215 \begin_inset Quotes sld
4218 some processors which are targetted by SDCC can be implemented in a
4235 \begin_inset LatexCommand \index{FPGA (field programmable gate array)}
4240 \begin_inset Quotes srd
4244 \begin_inset LatexCommand \url{http://sf.net/projects/fpgac}
4249 \begin_inset LatexCommand \index{FpgaC ((subset of) C to FPGA compiler)}
4254 \begin_inset Quotes sld
4257 have you ever heard of an open source compiler that compiles a subset of
4259 \begin_inset Quotes srd
4262 we expect you to have a quick look there and come back.
4263 If you read this you are on the right track.
4266 Some sections attribute more space to problems, restrictions and warnings
4267 than to the solution.
4270 The installation section and the section about the debugger is intimidating.
4273 There are still lots of typos and there are more different writing styles
4277 Testing the SDCC Compiler
4278 \begin_inset LatexCommand \label{sec:Testing-the-SDCC}
4285 The first thing you should do after installing your SDCC compiler is to
4301 \begin_inset LatexCommand \index{version}
4308 at the prompt, and the program should run and output its version like:
4313 SDCC : mcs51/z80/avr/ds390/pic16/pic14/ds400/hc08 2.5.6 #4169 (May 8 2006)
4317 If it doesn't run, or gives a message about not finding sdcc program, then
4318 you need to check over your installation.
4319 Make sure that the sdcc bin directory is in your executable search path
4320 defined by the PATH environment setting (
4325 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4332 Install trouble-shooting for suggestions
4335 Make sure that the sdcc program is in the bin folder, if not perhaps something
4336 did not install correctly.
4344 is commonly installed as described in section
4345 \begin_inset Quotes sld
4348 Install and search paths
4349 \begin_inset Quotes srd
4358 Make sure the compiler works on a very simple example.
4359 Type in the following test.c program using your favorite
4385 Compile this using the following command:
4394 If all goes well, the compiler will generate a test.asm and test.rel file.
4395 Congratulations, you've just compiled your first program with SDCC.
4396 We used the -c option to tell SDCC not to link the generated code, just
4397 to keep things simple for this step.
4405 The next step is to try it with the linker.
4415 If all goes well the compiler will link with the libraries and produce
4416 a test.ihx output file.
4421 (no test.ihx, and the linker generates warnings), then the problem is most
4430 usr/local/share/sdcc/lib directory
4437 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4444 Install trouble-shooting for suggestions).
4452 The final test is to ensure
4460 header files and libraries.
4461 Edit test.c and change it to the following:
4478 strcpy(str1, "testing");
4485 Compile this by typing
4492 This should generate a test.ihx output file, and it should give no warnings
4493 such as not finding the string.h file.
4494 If it cannot find the string.h file, then the problem is that
4498 cannot find the /usr/local/share/sdcc/include directory
4505 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
4512 Install trouble-shooting section for suggestions).
4530 \begin_inset LatexCommand \index{-\/-print-search-dirs}
4534 to find exactly where SDCC is looking for the include and lib files.
4537 Install Trouble-shooting
4538 \begin_inset LatexCommand \label{sub:Install-Trouble-shooting}
4543 \begin_inset LatexCommand \index{Install trouble-shooting}
4550 If SDCC does not build correctly
4553 A thing to try is starting from scratch by unpacking the .tgz source package
4554 again in an empty directory.
4562 ./configure 2>&1 | tee configure.log
4576 make 2>&1 | tee make.log
4583 If anything goes wrong, you can review the log files to locate the problem.
4584 Or a relevant part of this can be attached to an email that could be helpful
4585 when requesting help from the mailing list.
4589 \begin_inset Quotes sld
4593 \begin_inset Quotes srd
4600 \begin_inset Quotes sld
4604 \begin_inset Quotes srd
4607 command is a script that analyzes your system and performs some configuration
4608 to ensure the source package compiles on your system.
4609 It will take a few minutes to run, and will compile a few tests to determine
4610 what compiler features are installed.
4614 \begin_inset Quotes sld
4618 \begin_inset Quotes srd
4624 This runs the GNU make tool, which automatically compiles all the source
4625 packages into the final installed binary executables.
4629 \begin_inset Quotes sld
4633 \begin_inset Quotes erd
4639 This will install the compiler, other executables libraries and include
4640 files into the appropriate directories.
4642 \begin_inset LatexCommand \ref{sub:Install-paths}
4648 \begin_inset LatexCommand \ref{sub:Search-Paths}
4653 about install and search paths.
4655 On most systems you will need super-user privileges to do this.
4661 SDCC is not just a compiler, but a collection of tools by various developers.
4662 These include linkers, assemblers, simulators and other components.
4663 Here is a summary of some of the components.
4664 Note that the included simulator and assembler have separate documentation
4665 which you can find in the source package in their respective directories.
4666 As SDCC grows to include support for other processors, other packages from
4667 various developers are included and may have their own sets of documentation.
4671 You might want to look at the files which are installed in <installdir>.
4672 At the time of this writing, we find the following programs for gcc-builds:
4676 In <installdir>/bin:
4679 sdcc - The compiler.
4682 sdcpp - The C preprocessor.
4685 asx8051 - The assembler for 8051 type processors.
4692 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
4695 aslink -The linker for 8051 type processors.
4702 link-gbz80 - The Z80 and GameBoy Z80 linkers.
4705 s51 - The ucSim 8051 simulator.
4708 sdcdb - The source debugger.
4711 packihx - A tool to pack (compress) Intel hex files.
4714 In <installdir>/share/sdcc/include
4720 In <installdir>/share/sdcc/lib
4723 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
4727 In <installdir>/share/sdcc/doc
4733 As development for other processors proceeds, this list will expand to include
4734 executables to support processors like AVR, PIC, etc.
4740 This is the actual compiler, it in turn uses the c-preprocessor and invokes
4741 the assembler and linkage editor.
4744 sdcpp - The C-Preprocessor
4748 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
4752 is a modified version of the GNU cpp
4753 \begin_inset LatexCommand \index{cpp|see{sdcpp}}
4758 \begin_inset LatexCommand \url{http://gcc.gnu.org/}
4763 The C preprocessor is used to pull in #include sources, process #ifdef
4764 statements, #defines and so on.
4775 - The Assemblers and Linkage Editors
4778 This is retargettable assembler & linkage editor, it was developed by Alan
4780 John Hartman created the version for 8051, and I (Sandeep) have made some
4781 enhancements and bug fixes for it to work properly with SDCC.
4788 \begin_inset LatexCommand \index{s51}
4792 is a freeware, opensource simulator developed by Daniel Drotos.
4793 The simulator is built as part of the build process.
4794 For more information visit Daniel's web site at:
4795 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
4800 It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
4804 sdcdb - Source Level Debugger
4808 \begin_inset LatexCommand \index{SDCDB (debugger)}
4812 is the companion source level debugger.
4813 More about SDCDB in section
4814 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
4819 The current version of the debugger uses Daniel's Simulator S51
4820 \begin_inset LatexCommand \index{s51}
4824 , but can be easily changed to use other simulators.
4833 Single Source File Projects
4836 For single source file 8051 projects the process is very simple.
4837 Compile your programs with the following command
4840 "sdcc sourcefile.c".
4844 This will compile, assemble and link your source file.
4845 Output files are as follows:
4849 \begin_inset LatexCommand \index{<file>.asm}
4854 \begin_inset LatexCommand \index{Assembler source}
4858 file created by the compiler
4862 \begin_inset LatexCommand \index{<file>.lst}
4867 \begin_inset LatexCommand \index{Assembler listing}
4871 file created by the Assembler
4875 \begin_inset LatexCommand \index{<file>.rst}
4880 \begin_inset LatexCommand \index{Assembler listing}
4884 file updated with linkedit information, created by linkage editor
4888 \begin_inset LatexCommand \index{<file>.sym}
4893 \begin_inset LatexCommand \index{Symbol listing}
4897 for the sourcefile, created by the assembler
4901 \begin_inset LatexCommand \index{<file>.rel}
4906 \begin_inset LatexCommand \index{<file>.o}
4911 \begin_inset LatexCommand \index{Object file}
4915 created by the assembler, input to Linkage editor
4919 \begin_inset LatexCommand \index{<file>.map}
4924 \begin_inset LatexCommand \index{Memory map}
4928 for the load module, created by the Linker
4932 \begin_inset LatexCommand \index{<file>.mem}
4936 - A file with a summary of the memory usage
4940 \begin_inset LatexCommand \index{<file>.ihx}
4944 - The load module in Intel hex format
4945 \begin_inset LatexCommand \index{Intel hex format}
4949 (you can select the Motorola S19 format
4950 \begin_inset LatexCommand \index{Motorola S19 format}
4965 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
4970 If you need another format you might want to use
4977 \begin_inset LatexCommand \index{objdump (tool)}
4988 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
4993 Both formats are documented in the documentation of srecord
4994 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
5002 \begin_inset LatexCommand \index{<file>.adb}
5006 - An intermediate file containing debug information needed to create the
5018 \begin_inset LatexCommand \index{-\/-debug}
5026 \begin_inset LatexCommand \index{<file>.cdb}
5030 - An optional file (with -
5040 -debug) containing debug information.
5041 The format is documented in cdbfileformat.pdf
5046 \begin_inset LatexCommand \index{<file> (no extension)}
5050 An optional AOMF or AOMF51
5051 \begin_inset LatexCommand \index{AOMF, AOMF51}
5056 \begin_inset LatexCommand \label{OMF file}
5060 file containing debug information (generated with option -
5087 ormat is commonly used by third party tools (debuggers
5088 \begin_inset LatexCommand \index{Debugger}
5092 , simulators, emulators)
5096 \begin_inset LatexCommand \index{<file>.dump*}
5100 - Dump file to debug the compiler it self (generated with option -
5110 -dumpall) (see section
5111 \begin_inset LatexCommand \ref{sub:Intermediate-Dump-Options}
5117 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
5123 \begin_inset Quotes sld
5126 Anatomy of the compiler
5127 \begin_inset Quotes srd
5133 Postprocessing the Intel Hex
5134 \begin_inset LatexCommand \index{Intel hex format}
5141 In most cases this won't be needed but the Intel Hex file
5142 \begin_inset LatexCommand \index{<file>.ihx}
5146 which is generated by SDCC might include lines of varying length and the
5147 addresses within the file are not guaranteed to be strictly ascending.
5148 If your toolchain or a bootloader does not like this you can use the tool
5154 \begin_inset LatexCommand \index{packihx (tool)}
5158 which is part of the SDCC distribution:
5165 packihx sourcefile.ihx >sourcefile.hex
5172 The separately available
5177 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
5181 package additionally allows to set undefined locations to a predefined
5182 value, to insert checksums
5183 \begin_inset LatexCommand \index{checksum}
5187 of various flavours (crc, add, xor) and to perform other manipulations
5188 (convert, split, crop, offset, ...).
5196 srec_cat\SpecialChar ~
5198 sourcefile.ihx -intel\SpecialChar ~
5200 -o sourcefile.hex -intel
5207 An example for a more complex command line
5213 the command backfills
5214 \begin_inset LatexCommand \index{backfill unused memory}
5218 unused memory with 0x12 and the overall 16 bit sum of the complete 64 kByte
5220 If the program counter on an mcs51 runs wild the backfill pattern 0x12
5221 will be interpreted as an
5229 (where an emergency routine could sit).
5240 srec_cat\SpecialChar ~
5241 sourcefile.ihx -intel\SpecialChar ~
5243 -fill 0x12 0x0000 0xfffe\SpecialChar ~
5244 -little-endian-checksum-nega
5245 tive 0xfffe 0x02 0x02\SpecialChar ~
5247 -o sourcefile.hex -intel
5256 The srecord package is available at
5257 \begin_inset LatexCommand \url{http://sf.net/projects/srecord}
5264 Projects with Multiple Source Files
5267 SDCC can compile only ONE file at a time.
5268 Let us for example assume that you have a project containing the following
5273 foo1.c (contains some functions)
5275 foo2.c (contains some more functions)
5277 foomain.c (contains more functions and the function main)
5285 The first two files will need to be compiled separately with the commands:
5317 Then compile the source file containing the
5322 \begin_inset LatexCommand \index{Linker}
5326 the files together with the following command:
5334 foomain.c\SpecialChar ~
5335 foo1.rel\SpecialChar ~
5340 \begin_inset LatexCommand \index{<file>.rel}
5352 can be separately compiled as well:
5363 sdcc foomain.rel foo1.rel foo2.rel
5370 The file containing the
5385 file specified in the command line, since the linkage editor processes
5386 file in the order they are presented to it.
5387 The linker is invoked from SDCC using a script file with extension .lnk
5388 \begin_inset LatexCommand \index{<file>.lnk}
5393 You can view this file to troubleshoot linking problems such as those arising
5394 from missing libraries.
5397 Projects with Additional Libraries
5398 \begin_inset LatexCommand \index{Libraries}
5405 Some reusable routines may be compiled into a library, see the documentation
5406 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
5410 \begin_inset LatexCommand \index{<file>.lib}
5417 Libraries created in this manner can be included in the command line.
5418 Make sure you include the -L <library-path> option to tell the linker where
5419 to look for these files if they are not in the current directory.
5420 Here is an example, assuming you have the source file
5432 (if that is not the same as your current project):
5439 sdcc foomain.c foolib.lib -L mylib
5450 must be an absolute path name.
5454 The most efficient way to use libraries is to keep separate modules in separate
5456 The lib file now should name all the modules.rel
5457 \begin_inset LatexCommand \index{<file>.rel}
5462 For an example see the standard library file
5466 in the directory <installdir>/share/lib/small.
5469 Using sdcclib to Create and Manage Libraries
5470 \begin_inset LatexCommand \index{sdcclib}
5477 Alternatively, instead of having a .rel file for each entry on the library
5478 file as described in the preceding section, sdcclib can be used to embed
5479 all the modules belonging to such library in the library file itself.
5480 This results in a larger library file, but it greatly reduces the number
5481 of disk files accessed by the linker.
5482 Additionally, the packed library file contains an index of all include
5483 modules and symbols that significantly speeds up the linking process.
5484 To display a list of options supported by sdcclib type:
5493 \begin_inset LatexCommand \index{sdcclib}
5504 To create a new library file, start by compiling all the required modules.
5542 This will create files _divsint.rel, _divuint.rel, _modsint.rel, _moduint.rel,
5544 The next step is to add the .rel files to the library file:
5552 sdcclib libint.lib _divsint.rel
5555 \begin_inset LatexCommand \index{sdcclib}
5565 sdcclib libint.lib _divuint.rel
5571 sdcclib libint.lib _modsint.rel
5577 sdcclib libint.lib _moduint.rel
5583 sdcclib libint.lib _mulint.rel
5590 If the file already exists in the library, it will be replaced.
5591 To see what modules and symbols are included in the library, options -s
5592 and -m are available.
5600 sdcclib -s libint.lib
5603 \begin_inset LatexCommand \index{sdcclib}
5712 \added_space_bottom bigskip
5713 If the source files are compiled using -
5724 \begin_inset LatexCommand \index{-\/-debug}
5728 , the corresponding debug information file .adb will be include in the library
5730 The library files created with sdcclib are plain text files, so they can
5731 be viewed with a text editor.
5732 It is not recomended to modify a library file created with sdcclib using
5733 a text editor, as there are file indexes numbers located accross the file
5734 used by the linker to quickly locate the required module to link.
5735 Once a .rel file (as well as a .adb file) is added to a library using sdcclib,
5736 it can be safely deleted, since all the information required for linking
5737 is embedded in the library file itself.
5738 Library files created using sdcclib are used as described in the preceding
5742 Command Line Options
5743 \begin_inset LatexCommand \index{Command Line Options}
5750 Processor Selection Options
5751 \begin_inset LatexCommand \index{Options processor selection}
5756 \begin_inset LatexCommand \index{Processor selection options}
5762 \labelwidthstring 00.00.0000
5767 \begin_inset LatexCommand \index{-mmcs51}
5773 Generate code for the Intel MCS51
5774 \begin_inset LatexCommand \index{MCS51}
5778 family of processors.
5779 This is the default processor target.
5781 \labelwidthstring 00.00.0000
5786 \begin_inset LatexCommand \index{-mds390}
5792 Generate code for the Dallas DS80C390
5793 \begin_inset LatexCommand \index{DS80C390}
5799 \labelwidthstring 00.00.0000
5804 \begin_inset LatexCommand \index{-mds400}
5810 Generate code for the Dallas DS80C400
5811 \begin_inset LatexCommand \index{DS80C400}
5817 \labelwidthstring 00.00.0000
5822 \begin_inset LatexCommand \index{-mhc08}
5828 Generate code for the Freescale/Motorola HC08
5829 \begin_inset LatexCommand \index{HC08}
5833 family of processors.
5835 \labelwidthstring 00.00.0000
5840 \begin_inset LatexCommand \index{-mz80}
5846 Generate code for the Zilog Z80
5847 \begin_inset LatexCommand \index{Z80}
5851 family of processors.
5853 \labelwidthstring 00.00.0000
5858 \begin_inset LatexCommand \index{-mgbz80}
5864 Generate code for the GameBoy Z80
5865 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
5869 processor (Not actively maintained).
5871 \labelwidthstring 00.00.0000
5876 \begin_inset LatexCommand \index{-mavr}
5882 Generate code for the Atmel AVR
5883 \begin_inset LatexCommand \index{AVR}
5887 processor (Not maintained, not complete).
5888 AVR users should probably have a look at winavr
5889 \begin_inset LatexCommand \url{http://sourceforge.net/projects/winavr}
5894 \begin_inset LatexCommand \url{http://www.avrfreaks.net/index.php?name=PNphpBB2&file=index}
5901 I think it is fair to direct users there for now.
5902 Open source is also about avoiding unnecessary work .
5903 But I didn't find the 'official' link.
5905 \labelwidthstring 00.00.0000
5910 \begin_inset LatexCommand \index{-mpic14}
5916 Generate code for the Microchip PIC 14
5917 \begin_inset LatexCommand \index{PIC14}
5921 -bit processors (p16f84 and variants.
5922 In development, not complete).
5925 p16f627 p16f628 p16f84 p16f873 p16f877?
5927 \labelwidthstring 00.00.0000
5932 \begin_inset LatexCommand \index{-mpic16}
5938 Generate code for the Microchip PIC 16
5939 \begin_inset LatexCommand \index{PIC16}
5943 -bit processors (p18f452 and variants.
5944 In development, not complete).
5946 \labelwidthstring 00.00.0000
5952 Generate code for the Toshiba TLCS-900H
5953 \begin_inset LatexCommand \index{TLCS-900H}
5957 processor (Not maintained, not complete).
5959 \added_space_bottom bigskip \labelwidthstring 00.00.0000
5964 \begin_inset LatexCommand \index{-mxa51}
5970 Generate code for the Phillips XA51
5971 \begin_inset LatexCommand \index{XA51}
5975 processor (Not maintained, not complete).
5978 Preprocessor Options
5979 \begin_inset LatexCommand \index{Options preprocessor}
5984 \begin_inset LatexCommand \index{Preprocessor options}
5989 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
5995 \labelwidthstring 00.00.0000
6000 \begin_inset LatexCommand \index{-I<path>}
6006 The additional location where the pre processor will look for <..h> or
6007 \begin_inset Quotes eld
6011 \begin_inset Quotes erd
6016 \labelwidthstring 00.00.0000
6021 \begin_inset LatexCommand \index{-D<macro[=value]>}
6027 Command line definition of macros.
6028 Passed to the preprocessor.
6030 \labelwidthstring 00.00.0000
6035 \begin_inset LatexCommand \index{-M}
6041 Tell the preprocessor to output a rule suitable for make describing the
6042 dependencies of each object file.
6043 For each source file, the preprocessor outputs one make-rule whose target
6044 is the object file name for that source file and whose dependencies are
6045 all the files `#include'd in it.
6046 This rule may be a single line or may be continued with `
6048 '-newline if it is long.
6049 The list of rules is printed on standard output instead of the preprocessed
6052 \begin_inset LatexCommand \index{-E}
6058 \labelwidthstring 00.00.0000
6063 \begin_inset LatexCommand \index{-C}
6069 Tell the preprocessor not to discard comments.
6070 Used with the `-E' option.
6072 \labelwidthstring 00.00.0000
6077 \begin_inset LatexCommand \index{-MM}
6088 Like `-M' but the output mentions only the user header files included with
6090 \begin_inset Quotes eld
6094 System header files included with `#include <file>' are omitted.
6096 \labelwidthstring 00.00.0000
6101 \begin_inset LatexCommand \index{-Aquestion(answer)}
6107 Assert the answer answer for question, in case it is tested with a preprocessor
6108 conditional such as `#if #question(answer)'.
6109 `-A-' disables the standard assertions that normally describe the target
6112 \labelwidthstring 00.00.0000
6117 \begin_inset LatexCommand \index{-Umacro}
6123 Undefine macro macro.
6124 `-U' options are evaluated after all `-D' options, but before any `-include'
6125 and `-imacros' options.
6127 \labelwidthstring 00.00.0000
6132 \begin_inset LatexCommand \index{-dM}
6138 Tell the preprocessor to output only a list of the macro definitions that
6139 are in effect at the end of preprocessing.
6140 Used with the `-E' option.
6142 \labelwidthstring 00.00.0000
6147 \begin_inset LatexCommand \index{-dD}
6153 Tell the preprocessor to pass all macro definitions into the output, in
6154 their proper sequence in the rest of the output.
6156 \labelwidthstring 00.00.0000
6161 \begin_inset LatexCommand \index{-dN}
6172 Like `-dD' except that the macro arguments and contents are omitted.
6173 Only `#define name' is included in the output.
6175 \labelwidthstring 00.00.0000
6179 -pedantic-parse-number
6180 \begin_inset LatexCommand \index{-pedantic-parse-number}
6191 Pedentic parse numbers so that situations like 0xfe-LO_B(3) are parsed properly
6192 and the macro LO_B(3) gets expanded.
6193 See also #pragma pedantic_parse_number in section
6194 \begin_inset LatexCommand \ref{sec:Pragmas}
6200 Note: this functionality is not in conformance with standard!
6202 \added_space_bottom bigskip \labelwidthstring 00.00.0000
6207 preprocessorOption[,preprocessorOption]
6210 \begin_inset LatexCommand \index{-Wp preprocessorOption[,preprocessorOption]}
6215 Pass the preprocessorOption to the preprocessor
6220 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
6225 SDCC uses an adapted version of the preprocessor
6229 of the GNU Compiler Collection
6230 \begin_inset LatexCommand \index{gcc (GNU Compiler Collection)}
6239 \begin_inset LatexCommand \url{http://gcc.gnu.org/}
6243 ), if you need more dedicated options please refer to the GCC\SpecialChar ~
6248 \begin_inset LatexCommand \htmlurl{http://www.gnu.org/software/gcc/onlinedocs/}
6256 \begin_inset LatexCommand \index{Options linker}
6261 \begin_inset LatexCommand \index{Linker options}
6267 \labelwidthstring 00.00.0000
6287 \begin_inset LatexCommand \index{-\/-lib-path <path>}
6292 \begin_inset LatexCommand \index{-L -\/-lib-path}
6299 <absolute path to additional libraries> This option is passed to the linkage
6300 editor's additional libraries
6301 \begin_inset LatexCommand \index{Libraries}
6306 The path name must be absolute.
6307 Additional library files may be specified in the command line.
6308 See section Compiling programs for more details.
6310 \labelwidthstring 00.00.0000
6327 \begin_inset LatexCommand \index{-\/-xram-loc <Value>}
6332 <Value> The start location of the external ram
6333 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
6337 , default value is 0.
6338 The value entered can be in Hexadecimal or Decimal format, e.g.: -
6348 -xram-loc 0x8000 or -
6360 \labelwidthstring 00.00.0000
6377 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
6382 <Value> The start location of the code
6383 \begin_inset LatexCommand \index{code}
6387 segment, default value 0.
6388 Note when this option is used the interrupt vector table
6389 \begin_inset LatexCommand \index{interrupt vector table}
6393 is also relocated to the given address.
6394 The value entered can be in Hexadecimal or Decimal format, e.g.: -
6404 -code-loc 0x8000 or -
6416 \labelwidthstring 00.00.0000
6433 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
6438 <Value> By default the stack
6439 \begin_inset LatexCommand \index{stack}
6443 is placed after the data segment.
6444 Using this option the stack can be placed anywhere in the internal memory
6446 The value entered can be in Hexadecimal or Decimal format, e.g.
6457 -stack-loc 0x20 or -
6468 Since the sp register is incremented before a push or call, the initial
6469 sp will be set to one byte prior the provided value.
6470 The provided value should not overlap any other memory areas such as used
6471 register banks or the data segment and with enough space for the current
6489 \begin_inset LatexCommand \index{-\/-pack-iram}
6493 option (which is now a default setting) will override this setting, so
6494 you should also specify the
6510 \begin_inset LatexCommand \index{-\/-no-pack-iram}
6514 option if you need to manually place the stack.
6516 \labelwidthstring 00.00.0000
6533 \begin_inset LatexCommand \index{-\/-xstack-loc <Value>}
6538 <Value> By default the external stack
6539 \begin_inset LatexCommand \index{xstack}
6543 is placed after the pdata
6544 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
6549 Using this option the xstack can be placed anywhere in the external memory
6551 The value entered can be in Hexadecimal or Decimal format, e.g.
6562 -xstack-loc 0x8000 or -
6573 The provided value should not overlap any other memory areas such as the
6574 pdata or xdata segment and with enough space for the current application.
6576 \labelwidthstring 00.00.0000
6593 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
6598 <Value> The start location of the internal ram data
6599 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
6604 The value entered can be in Hexadecimal or Decimal format, eg.
6626 (By default, the start location of the internal ram data segment is set
6627 as low as possible in memory, taking into account the used register banks
6628 and the bit segment at address 0x20.
6629 For example if register banks 0 and 1 are used without bit variables, the
6630 data segment will be set, if -
6640 -data-loc is not used, to location 0x10.)
6642 \labelwidthstring 00.00.0000
6659 \begin_inset LatexCommand \index{-\/-idata-loc <Value>}
6664 <Value> The start location of the indirectly addressable internal ram
6665 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
6669 of the 8051, default value is 0x80.
6670 The value entered can be in Hexadecimal or Decimal format, eg.
6681 -idata-loc 0x88 or -
6693 \labelwidthstring 00.00.0000
6710 <Value> The start location of the bit
6711 \begin_inset LatexCommand \index{bit}
6715 addressable internal ram of the 8051.
6721 Instead an option can be passed directly to the linker: -Wl\SpecialChar ~
6724 \labelwidthstring 00.00.0000
6739 \begin_inset LatexCommand \index{-\/-out-fmt-ihx}
6748 The linker output (final object code) is in Intel Hex format.
6749 \begin_inset LatexCommand \index{Intel hex format}
6753 This is the default option.
6754 The format itself is documented in the documentation of srecord
6755 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
6761 \labelwidthstring 00.00.0000
6776 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
6785 The linker output (final object code) is in Motorola S19 format
6786 \begin_inset LatexCommand \index{Motorola S19 format}
6791 The format itself is documented in the documentation of srecord.
6793 \labelwidthstring 00.00.0000
6808 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
6813 \begin_inset LatexCommand \index{HC08!Options!-\/-out-fmt-elf}
6822 The linker output (final object code) is in ELF format
6823 \begin_inset LatexCommand \index{ELF format}
6828 (Currently only supported for the HC08
6829 \begin_inset LatexCommand \index{HC08}
6835 \added_space_bottom bigskip \labelwidthstring 00.00.0000
6840 linkOption[,linkOption]
6843 \begin_inset LatexCommand \index{-Wl linkOption[,linkOption]}
6848 Pass the linkOption to the linker.
6849 If a bootloader is used an option like
6850 \begin_inset Quotes sld
6855 \begin_inset Quotes srd
6858 would be typical to set the start of the code segment.
6859 See also #pragma constseg and #pragma codeseg in section
6860 \begin_inset LatexCommand \ref{sec:Pragmas}
6865 File sdcc/as/doc/asxhtm.html has more on linker options.
6869 \begin_inset LatexCommand \index{Options MCS51}
6874 \begin_inset LatexCommand \index{MCS51 options}
6880 \labelwidthstring 00.00.0000
6895 \begin_inset LatexCommand \index{-\/-model-small}
6906 Generate code for Small Model programs, see section Memory Models for more
6908 This is the default model.
6910 \labelwidthstring 00.00.0000
6925 \begin_inset LatexCommand \index{-\/-model-medium}
6931 Generate code for Medium model programs, see section Memory Models for
6933 If this option is used all source files in the project have to be compiled
6935 It must also be used when invoking the linker.
6937 \labelwidthstring 00.00.0000
6952 \begin_inset LatexCommand \index{-\/-model-large}
6958 Generate code for Large model programs, see section Memory Models for more
6960 If this option is used all source files in the project have to be compiled
6962 It must also be used when invoking the linker.
6964 \labelwidthstring 00.00.0000
6979 \begin_inset LatexCommand \index{-\/-xstack}
6985 Uses a pseudo stack in the pdata
6986 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
6990 area (usually the first 256 bytes in the external ram) for allocating variables
6991 and passing parameters.
6993 \begin_inset LatexCommand \ref{sub:External-Stack}
6998 External Stack for more details.
7000 \labelwidthstring 00.00.0000
7018 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
7022 Causes the linker to check if the internal ram usage is within limits of
7025 \labelwidthstring 00.00.0000
7043 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
7047 Causes the linker to check if the external ram usage is within limits of
7050 \labelwidthstring 00.00.0000
7068 \begin_inset LatexCommand \index{-\/-code-size <Value>}
7072 Causes the linker to check if the code memory usage is within limits of
7075 \labelwidthstring 00.00.0000
7093 \begin_inset LatexCommand \index{-\/-stack-size <Value>}
7097 Causes the linker to check if there is at minimum <Value> bytes for stack.
7099 \labelwidthstring 00.00.0000
7117 \begin_inset LatexCommand \index{-\/-pack-iram}
7121 Causes the linker to use unused register banks for data variables and pack
7122 data, idata and stack together.
7123 This is the default now.
7125 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7143 \begin_inset LatexCommand \index{-\/-no-pack-iram}
7147 Causes the linker to use old style for allocating memory areas.
7150 DS390 / DS400 Options
7151 \begin_inset LatexCommand \index{Options DS390}
7156 \begin_inset LatexCommand \index{DS390}
7162 \labelwidthstring 00.00.0000
7179 \begin_inset LatexCommand \index{DS390!Options!-\/-model-flat24}
7189 Generate 24-bit flat mode code.
7190 This is the one and only that the ds390 code generator supports right now
7191 and is default when using
7196 See section Memory Models for more details.
7198 \labelwidthstring 00.00.0000
7213 \begin_inset LatexCommand \index{DS390!Options!-\/-protect-sp-update}
7219 disable interrupts during ESP:SP updates.
7221 \labelwidthstring 00.00.0000
7238 \begin_inset LatexCommand \index{DS390!Options!-\/-stack-10bit}
7242 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
7243 This is the one and only that the ds390 code generator supports right now
7244 and is default when using
7249 In this mode, the stack is located in the lower 1K of the internal RAM,
7250 which is mapped to 0x400000.
7251 Note that the support is incomplete, since it still uses a single byte
7252 as the stack pointer.
7253 This means that only the lower 256 bytes of the potential 1K stack space
7254 will actually be used.
7255 However, this does allow you to reclaim the precious 256 bytes of low RAM
7256 for use for the DATA and IDATA segments.
7257 The compiler will not generate any code to put the processor into 10 bit
7259 It is important to ensure that the processor is in this mode before calling
7260 any re-entrant functions compiled with this option.
7261 In principle, this should work with the
7274 \begin_inset LatexCommand \index{-\/-stack-auto}
7280 option, but that has not been tested.
7281 It is incompatible with the
7294 \begin_inset LatexCommand \index{-\/-xstack}
7301 It also only makes sense if the processor is in 24 bit contiguous addressing
7314 -model-flat24 option
7318 \labelwidthstring 00.00.0000
7333 \begin_inset LatexCommand \index{DS390!Options!-\/-stack-probe}
7339 insert call to function __stack_probe at each function prologue.
7341 \labelwidthstring 00.00.0000
7356 \begin_inset LatexCommand \index{DS390!Options!-\/-tini-libid}
7362 <nnnn> LibraryID used in -mTININative.
7365 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7380 \begin_inset LatexCommand \index{DS390!Options!-\/-use-accelerator}
7386 generate code for DS390 Arithmetic Accelerator.
7391 \begin_inset LatexCommand \index{Options Z80}
7396 \begin_inset LatexCommand \index{Z80}
7402 \labelwidthstring 00.00.0000
7419 \begin_inset LatexCommand \index{Z80!Options!-\/-callee-saves-bc}
7429 Force a called function to always save BC.
7431 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7448 \begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}
7452 When linking, skip the standard crt0.o object file.
7453 You must provide your own crt0.o for your system when linking.
7457 Optimization Options
7458 \begin_inset LatexCommand \index{Options optimization}
7463 \begin_inset LatexCommand \index{Optimization options}
7469 \labelwidthstring 00.00.0000
7484 \begin_inset LatexCommand \index{-\/-nogcse}
7490 Will not do global subexpression elimination, this option may be used when
7491 the compiler creates undesirably large stack/data spaces to store compiler
7501 \begin_inset LatexCommand \index{sloc (spill location)}
7506 A warning message will be generated when this happens and the compiler
7507 will indicate the number of extra bytes it allocated.
7508 It is recommended that this option NOT be used, #pragma\SpecialChar ~
7510 \begin_inset LatexCommand \index{\#pragma nogcse}
7514 can be used to turn off global subexpression elimination
7515 \begin_inset LatexCommand \index{Subexpression elimination}
7519 for a given function only.
7521 \labelwidthstring 00.00.0000
7536 \begin_inset LatexCommand \index{-\/-noinvariant}
7542 Will not do loop invariant optimizations, this may be turned off for reasons
7543 explained for the previous option.
7544 For more details of loop optimizations performed see Loop Invariants in
7546 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
7551 It is recommended that this option NOT be used, #pragma\SpecialChar ~
7553 \begin_inset LatexCommand \index{\#pragma noinvariant}
7557 can be used to turn off invariant optimizations for a given function only.
7559 \labelwidthstring 00.00.0000
7574 \begin_inset LatexCommand \index{-\/-noinduction}
7580 Will not do loop induction optimizations, see section strength reduction
7582 It is recommended that this option is NOT used, #pragma\SpecialChar ~
7584 \begin_inset LatexCommand \index{\#pragma noinduction}
7588 can be used to turn off induction optimizations for a given function only.
7590 \labelwidthstring 00.00.0000
7605 \begin_inset LatexCommand \index{-\/-nojtbound}
7616 Will not generate boundary condition check when switch statements
7617 \begin_inset LatexCommand \index{switch statement}
7621 are implemented using jump-tables.
7623 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
7628 Switch Statements for more details.
7629 It is recommended that this option is NOT used, #pragma\SpecialChar ~
7631 \begin_inset LatexCommand \index{\#pragma nojtbound}
7635 can be used to turn off boundary checking for jump tables for a given function
7638 \labelwidthstring 00.00.0000
7653 \begin_inset LatexCommand \index{-\/-noloopreverse}
7662 Will not do loop reversal
7663 \begin_inset LatexCommand \index{Loop reversing}
7669 \labelwidthstring 00.00.0000
7686 \begin_inset LatexCommand \index{-\/-nolabelopt }
7690 Will not optimize labels (makes the dumpfiles more readable).
7692 \labelwidthstring 00.00.0000
7707 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
7713 Will not memcpy initialized data from code space into xdata space.
7714 This saves a few bytes in code space if you don't have initialized data
7715 \begin_inset LatexCommand \index{Variable initialization}
7721 \labelwidthstring 00.00.0000
7736 \begin_inset LatexCommand \index{-\/-nooverlay}
7742 The compiler will not overlay parameters and local variables of any function,
7743 see section Parameters and local variables for more details.
7745 \labelwidthstring 00.00.0000
7760 \begin_inset LatexCommand \index{-\/-no-peep}
7766 Disable peep-hole optimization with built-in rules.
7768 \labelwidthstring 00.00.0000
7785 \begin_inset LatexCommand \index{-\/-peep-file}
7790 <filename> This option can be used to use additional rules to be used by
7791 the peep hole optimizer.
7793 \begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
7798 Peep Hole optimizations for details on how to write these rules.
7800 \labelwidthstring 00.00.0000
7815 \begin_inset LatexCommand \index{-\/-peep-asm}
7821 Pass the inline assembler code through the peep hole optimizer.
7822 This can cause unexpected changes to inline assembler code, please go through
7823 the peephole optimizer
7824 \begin_inset LatexCommand \index{Peephole optimizer}
7828 rules defined in the source file tree '<target>/peeph.def' before using
7831 \labelwidthstring 00.00.0000
7846 \begin_inset LatexCommand \index{-\/-opt-code-speed}
7852 The compiler will optimize code generation towards fast code, possibly
7853 at the expense of code size.
7855 \added_space_bottom bigskip \labelwidthstring 00.00.0000
7870 \begin_inset LatexCommand \index{-\/-opt-code-size}
7876 The compiler will optimize code generation towards compact code, possibly
7877 at the expense of code speed.
7881 \begin_inset LatexCommand \index{Options other}
7887 \labelwidthstring 00.00.0000
7903 \begin_inset LatexCommand \index{-\/-compile-only}
7908 \begin_inset LatexCommand \index{-c -\/-compile-only}
7914 will compile and assemble the source, but will not call the linkage editor.
7916 \labelwidthstring 00.00.0000
7935 \begin_inset LatexCommand \index{-\/-c1mode}
7941 reads the preprocessed source from standard input and compiles it.
7942 The file name for the assembler output must be specified using the -o option.
7944 \labelwidthstring 00.00.0000
7949 \begin_inset LatexCommand \index{-E}
7955 Run only the C preprocessor.
7956 Preprocess all the C source files specified and output the results to standard
7959 \labelwidthstring 00.00.0000
7965 \begin_inset LatexCommand \index{-o <path/file>}
7971 The output path resp.
7972 file where everything will be placed.
7973 If the parameter is a path, it must have a trailing slash (or backslash
7974 for the Windows binaries) to be recognized as a path.
7977 \labelwidthstring 00.00.0000
7992 \begin_inset LatexCommand \index{-\/-stack-auto}
8003 All functions in the source file will be compiled as
8008 \begin_inset LatexCommand \index{reentrant}
8013 the parameters and local variables will be allocated on the stack
8014 \begin_inset LatexCommand \index{stack}
8020 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
8024 Parameters and Local Variables for more details.
8025 If this option is used all source files in the project should be compiled
8027 It automatically implies --int-long-reent and --float-reent.
8030 \labelwidthstring 00.00.0000
8045 \begin_inset LatexCommand \index{-\/-callee-saves}
8049 function1[,function2][,function3]....
8052 The compiler by default uses a caller saves convention for register saving
8053 across function calls, however this can cause unnecessary register pushing
8054 & popping when calling small functions from larger functions.
8055 This option can be used to switch the register saving convention for the
8056 function names specified.
8057 The compiler will not save registers when calling these functions, no extra
8058 code will be generated at the entry & exit (function prologue
8061 \begin_inset LatexCommand \index{function prologue}
8070 \begin_inset LatexCommand \index{function epilogue}
8076 ) for these functions to save & restore the registers used by these functions,
8077 this can SUBSTANTIALLY reduce code & improve run time performance of the
8079 In the future the compiler (with inter procedural analysis) will be able
8080 to determine the appropriate scheme to use for each function call.
8081 DO NOT use this option for built-in functions such as _mulint..., if this
8082 option is used for a library function the appropriate library function
8083 needs to be recompiled with the same option.
8084 If the project consists of multiple source files then all the source file
8085 should be compiled with the same -
8095 -callee-saves option string.
8096 Also see #pragma\SpecialChar ~
8098 \begin_inset LatexCommand \index{\#pragma callee\_saves}
8104 \labelwidthstring 00.00.0000
8119 \begin_inset LatexCommand \index{-\/-debug}
8128 When this option is used the compiler will generate debug information.
8129 The debug information collected in a file with .cdb extension can be used
8131 For more information see documentation for SDCDB.
8132 Another file with no extension contains debug information in AOMF or AOMF51
8133 \begin_inset LatexCommand \index{AOMF, AOMF51}
8137 format which is commonly used by third party tools.
8139 \labelwidthstring 00.00.0000
8144 \begin_inset LatexCommand \index{-S}
8155 Stop after the stage of compilation proper; do not assemble.
8156 The output is an assembler code file for the input file specified.
8158 \labelwidthstring 00.00.0000
8173 \begin_inset LatexCommand \index{-\/-int-long-reent}
8179 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
8180 Note by default these libraries are compiled as non-reentrant.
8181 See section Installation for more details.
8183 \labelwidthstring 00.00.0000
8198 \begin_inset LatexCommand \index{-\/-cyclomatic}
8207 This option will cause the compiler to generate an information message for
8208 each function in the source file.
8209 The message contains some
8213 information about the function.
8214 The number of edges and nodes the compiler detected in the control flow
8215 graph of the function, and most importantly the
8217 cyclomatic complexity
8218 \begin_inset LatexCommand \index{Cyclomatic complexity}
8224 see section on Cyclomatic Complexity for more details.
8226 \labelwidthstring 00.00.0000
8241 \begin_inset LatexCommand \index{-\/-float-reent}
8247 Floating point library is compiled as reentrant
8248 \begin_inset LatexCommand \index{reentrant}
8253 See section Installation for more details.
8255 \labelwidthstring 00.00.0000
8270 \begin_inset LatexCommand \index{-\/-main-return}
8276 This option can be used if the code generated is called by a monitor program
8277 or if the main routine includes an endless loop.
8278 This option results in slightly smaller code and saves two bytes of stack
8280 The return from the 'main'
8281 \begin_inset LatexCommand \index{main return}
8285 function will return to the function calling main.
8286 The default setting is to lock up i.e.
8293 \labelwidthstring 00.00.0000
8308 \begin_inset LatexCommand \index{-\/-nostdinc}
8314 This will prevent the compiler from passing on the default include path
8315 to the preprocessor.
8317 \labelwidthstring 00.00.0000
8332 \begin_inset LatexCommand \index{-\/-nostdlib}
8338 This will prevent the compiler from passing on the default library
8339 \begin_inset LatexCommand \index{Libraries}
8345 \labelwidthstring 00.00.0000
8360 \begin_inset LatexCommand \index{-\/-verbose}
8366 Shows the various actions the compiler is performing.
8368 \labelwidthstring 00.00.0000
8373 \begin_inset LatexCommand \index{-V}
8379 Shows the actual commands the compiler is executing.
8381 \labelwidthstring 00.00.0000
8396 \begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
8402 Hides your ugly and inefficient c-code from the asm file, so you can always
8403 blame the compiler :)
8405 \labelwidthstring 00.00.0000
8420 \begin_inset LatexCommand \index{-\/-no-peep-comments}
8426 Will not include peep-hole comments in the generated files.
8428 \labelwidthstring 00.00.0000
8443 \begin_inset LatexCommand \index{-\/-i-code-in-asm}
8449 Include i-codes in the asm file.
8450 Sounds like noise but is most helpful for debugging the compiler itself.
8452 \labelwidthstring 00.00.0000
8467 \begin_inset LatexCommand \index{-\/-less-pedantic}
8473 Disable some of the more pedantic warnings
8474 \begin_inset LatexCommand \index{Warnings}
8478 (jwk burps: please be more specific here, please!).
8480 \labelwidthstring 00.00.0000
8494 -disable-warning\SpecialChar ~
8496 \begin_inset LatexCommand \index{-\/-disable-warning}
8502 Disable specific warning with number <nnnn>.
8504 \labelwidthstring 00.00.0000
8519 \begin_inset LatexCommand \index{-\/-print-search-dirs}
8525 Display the directories in the compiler's search path
8527 \labelwidthstring 00.00.0000
8542 \begin_inset LatexCommand \index{-\/-vc}
8548 Display errors and warnings using MSVC style, so you can use SDCC with
8549 the visual studio IDE
8550 \begin_inset LatexCommand \index{IDE}
8555 With SDCC both offering a GCC-like (the default) and a MSVC-like
8556 \begin_inset LatexCommand \index{MSVC output style}
8560 output style, integration into most programming editors should be straightforwa
8563 \labelwidthstring 00.00.0000
8578 \begin_inset LatexCommand \index{-\/-use-stdout}
8584 Send errors and warnings to stdout instead of stderr.
8586 \labelwidthstring 00.00.0000
8591 asmOption[,asmOption]
8594 \begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
8599 Pass the asmOption to the assembler
8600 \begin_inset LatexCommand \index{Options assembler}
8605 \begin_inset LatexCommand \index{Assembler options}
8610 See file sdcc/as/doc/asxhtm.html for assembler options.cd
8612 \labelwidthstring 00.00.0000
8627 \begin_inset LatexCommand \index{-\/-std-sdcc89}
8633 Generally follow the C89 standard, but allow SDCC features that conflict
8634 with the standard (default).
8636 \labelwidthstring 00.00.0000
8651 \begin_inset LatexCommand \index{-\/-std-c89}
8657 Follow the C89 standard and disable SDCC features that conflict with the
8660 \labelwidthstring 00.00.0000
8675 \begin_inset LatexCommand \index{-\/-std-sdcc99}
8681 Generally follow the C99 standard, but allow SDCC features that conflict
8682 with the standard (incomplete support).
8684 \labelwidthstring 00.00.0000
8699 \begin_inset LatexCommand \index{-\/-std-sdcc99}
8705 Follow the C99 standard and disable SDCC features that conflict with the
8706 standard (incomplete support).
8708 \labelwidthstring 00.00.0000
8725 \begin_inset LatexCommand \index{-\/-codeseg <Value>}
8730 <Name> The name to be used for the code
8731 \begin_inset LatexCommand \index{code}
8735 segment, default CSEG.
8736 This is useful if you need to tell the compiler to put the code in a special
8737 segment so you can later on tell the linker to put this segment in a special
8739 Can be used for instance when using bank switching to put the code in a
8742 \labelwidthstring 00.00.0000
8759 \begin_inset LatexCommand \index{-\/-constseg <Value>}
8764 <Name> The name to be used for the const
8765 \begin_inset LatexCommand \index{code}
8769 segment, default CONST.
8770 This is useful if you need to tell the compiler to put the const data in
8771 a special segment so you can later on tell the linker to put this segment
8772 in a special place in memory.
8773 Can be used for instance when using bank switching to put the const data
8776 \added_space_bottom bigskip \labelwidthstring 00.00.0000
8788 a SDCC compiler option but if you want
8792 warnings you can use a separate tool dedicated to syntax checking like
8794 \begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
8799 \begin_inset LatexCommand \index{lint (syntax checking tool)}
8804 \begin_inset LatexCommand \url{http://www.splint.org}
8809 To make your source files parseable by splint you will have to include
8815 \begin_inset LatexCommand \index{splint (syntax checking tool)}
8819 in your source file and add brackets around extended keywords (like
8822 \begin_inset Quotes sld
8835 \begin_inset Quotes srd
8843 \begin_inset Quotes sld
8846 __interrupt\SpecialChar ~
8848 \begin_inset Quotes srd
8856 Splint has an excellent on line manual at
8857 \begin_inset LatexCommand \url{http://www.splint.org/manual/}
8861 and it's capabilities go beyond pure syntax checking.
8862 You'll need to tell splint the location of SDCC's include files so a typical
8863 command line could look like this:
8867 splint\SpecialChar ~
8869 /usr/local/share/sdcc/include/mcs51/\SpecialChar ~
8874 Intermediate Dump Options
8875 \begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
8880 \begin_inset LatexCommand \index{Options intermediate dump}
8885 \begin_inset LatexCommand \index{Intermediate dump options}
8892 The following options are provided for the purpose of retargetting and debugging
8894 They provide a means to dump the intermediate code (iCode
8895 \begin_inset LatexCommand \index{iCode}
8899 ) generated by the compiler in human readable form at various stages of
8900 the compilation process.
8901 More on iCodes see chapter
8902 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
8907 \begin_inset Quotes srd
8910 The anatomy of the compiler
8911 \begin_inset Quotes srd
8916 \labelwidthstring 00.00.0000
8931 \begin_inset LatexCommand \index{-\/-dumpraw}
8937 This option will cause the compiler to dump the intermediate code into
8940 <source filename>.dumpraw
8942 just after the intermediate code has been generated for a function, i.e.
8943 before any optimizations are done.
8945 \begin_inset LatexCommand \index{Basic blocks}
8949 at this stage ordered in the depth first number, so they may not be in
8950 sequence of execution.
8952 \labelwidthstring 00.00.0000
8967 \begin_inset LatexCommand \index{-\/-dumpgcse}
8973 Will create a dump of iCode's, after global subexpression elimination
8974 \begin_inset LatexCommand \index{Global subexpression elimination}
8980 <source filename>.dumpgcse.
8982 \labelwidthstring 00.00.0000
8997 \begin_inset LatexCommand \index{-\/-dumpdeadcode}
9003 Will create a dump of iCode's, after deadcode elimination
9004 \begin_inset LatexCommand \index{Dead-code elimination}
9010 <source filename>.dumpdeadcode.
9012 \labelwidthstring 00.00.0000
9027 \begin_inset LatexCommand \index{-\/-dumploop}
9036 Will create a dump of iCode's, after loop optimizations
9037 \begin_inset LatexCommand \index{Loop optimization}
9043 <source filename>.dumploop.
9045 \labelwidthstring 00.00.0000
9060 \begin_inset LatexCommand \index{-\/-dumprange}
9069 Will create a dump of iCode's, after live range analysis
9070 \begin_inset LatexCommand \index{Live range analysis}
9076 <source filename>.dumprange.
9078 \labelwidthstring 00.00.0000
9093 \begin_inset LatexCommand \index{-\/-dumlrange}
9099 Will dump the life ranges
9100 \begin_inset LatexCommand \index{Live range analysis}
9106 \labelwidthstring 00.00.0000
9121 \begin_inset LatexCommand \index{-\/-dumpregassign}
9130 Will create a dump of iCode's, after register assignment
9131 \begin_inset LatexCommand \index{Register assignment}
9137 <source filename>.dumprassgn.
9139 \labelwidthstring 00.00.0000
9154 \begin_inset LatexCommand \index{-\/-dumplrange}
9160 Will create a dump of the live ranges of iTemp's
9162 \added_space_bottom bigskip \labelwidthstring 00.00.0000
9177 \begin_inset LatexCommand \index{-\/-dumpall}
9188 Will cause all the above mentioned dumps to be created.
9191 Redirecting output on Windows Shells
9193 \added_space_bottom bigskip
9194 By default SDCC writes it's error messages to
9195 \begin_inset Quotes sld
9199 \begin_inset Quotes srd
9203 To force all messages to
9204 \begin_inset Quotes sld
9208 \begin_inset Quotes srd
9232 \begin_inset LatexCommand \index{-\/-use-stdout}
9237 Additionally, if you happen to have visual studio installed in your windows
9238 machine, you can use it to compile your sources using a custom build and
9254 \begin_inset LatexCommand \index{-\/-vc}
9259 Something like this should work:
9303 -model-large -c $(InputPath)
9306 Environment variables
9307 \begin_inset LatexCommand \index{Environment variables}
9314 SDCC recognizes the following environment variables:
9316 \labelwidthstring 00.00.0000
9321 \begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
9327 SDCC installs a signal handler
9328 \begin_inset LatexCommand \index{signal handler}
9332 to be able to delete temporary files after an user break (^C) or an exception.
9333 If this environment variable is set, SDCC won't install the signal handler
9334 in order to be able to debug SDCC.
9336 \labelwidthstring 00.00.0000
9343 \begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
9349 Path, where temporary files will be created.
9350 The order of the variables is the search order.
9351 In a standard *nix environment these variables are not set, and there's
9352 no need to set them.
9353 On Windows it's recommended to set one of them.
9355 \labelwidthstring 00.00.0000
9360 \begin_inset LatexCommand \index{SDCC\_HOME}
9367 \begin_inset LatexCommand \ref{sub:Install-paths}
9373 \begin_inset Quotes sld
9377 \begin_inset Quotes srd
9382 \labelwidthstring 00.00.0000
9387 \begin_inset LatexCommand \index{SDCC\_INCLUDE}
9394 \begin_inset LatexCommand \ref{sub:Search-Paths}
9400 \begin_inset Quotes sld
9404 \begin_inset Quotes srd
9409 \labelwidthstring 00.00.0000
9414 \begin_inset LatexCommand \index{SDCC\_LIB}
9421 \begin_inset LatexCommand \ref{sub:Search-Paths}
9427 \begin_inset Quotes sld
9431 \begin_inset Quotes srd
9436 \added_space_bottom bigskip
9437 There are some more environment variables recognized by SDCC, but these
9438 are solely used for debugging purposes.
9439 They can change or disappear very quickly, and will never be documented.
9442 Storage Class Language Extensions
9445 MCS51/DS390 Storage Class
9446 \begin_inset LatexCommand \index{Storage class}
9453 In addition to the ANSI storage classes SDCC allows the following MCS51
9454 specific storage classes:
9455 \layout Subsubsection
9458 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
9463 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
9468 \begin_inset LatexCommand \index{near (storage class)}
9473 \begin_inset LatexCommand \index{\_\_near (storage class)}
9484 storage class for the Small Memory model (
9492 or the more ANSI-C compliant forms
9500 can be used synonymously).
9501 Variables declared with this storage class will be allocated in the directly
9502 addressable portion of the internal RAM of a 8051, e.g.:
9507 __data unsigned char test_data;
9510 Writing 0x01 to this variable generates the assembly code:
9515 75*00 01\SpecialChar ~
9521 \layout Subsubsection
9524 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9529 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
9534 \begin_inset LatexCommand \index{far (storage class)}
9539 \begin_inset LatexCommand \index{\_\_far (storage class)}
9546 Variables declared with this storage class will be placed in the external
9552 storage class for the Large Memory model, e.g.:
9557 __xdata unsigned char test_xdata;
9560 Writing 0x01 to this variable generates the assembly code:
9565 90s00r00\SpecialChar ~
9594 \layout Subsubsection
9597 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
9602 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
9609 Variables declared with this storage class will be allocated into the indirectly
9610 addressable portion of the internal ram of a 8051, e.g.:
9615 __idata unsigned char test_idata;
9618 Writing 0x01 to this variable generates the assembly code:
9647 Please note, the first 128 byte of idata physically access the same RAM
9649 The original 8051 had 128 byte idata memory, nowadays most devices have
9650 256 byte idata memory.
9652 \begin_inset LatexCommand \index{stack}
9656 is located in idata memory.
9657 \layout Subsubsection
9660 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
9665 \begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
9672 Paged xdata access is just as straightforward as using the other addressing
9674 It is typically located at the start of xdata and has a maximum size of
9676 The following example writes 0x01 to the pdata variable.
9677 Please note, pdata access physically accesses xdata memory.
9678 The high byte of the address is determined by port P2
9679 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
9683 (or in case of some 8051 variants by a separate Special Function Register,
9685 \begin_inset LatexCommand \ref{sub:MCS51-variants}
9694 storage class for the Medium Memory model, e.g.:
9699 __pdata unsigned char test_pdata;
9702 Writing 0x01 to this variable generates the assembly code:
9746 \begin_inset LatexCommand \index{-\/-xstack}
9750 option is used the pdata memory area is followed by the xstack memory area
9751 and the sum of their sizes is limited to 256 bytes.
9752 \layout Subsubsection
9755 \begin_inset LatexCommand \index{code}
9760 \begin_inset LatexCommand \index{\_\_code}
9767 'Variables' declared with this storage class will be placed in the code
9773 __code unsigned char test_code;
9776 Read access to this variable generates the assembly code:
9781 90s00r6F\SpecialChar ~
9784 mov dptr,#_test_code
9813 indexed arrays of characters in code memory can be accessed efficiently:
9818 __code char test_array[] = {'c','h','e','a','p'};
9821 Read access to this array using an 8-bit unsigned index generates the assembly
9838 90s00r41\SpecialChar ~
9841 mov dptr,#_test_array
9856 \layout Subsubsection
9859 \begin_inset LatexCommand \index{bit}
9864 \begin_inset LatexCommand \index{\_\_bit}
9871 This is a data-type and a storage class specifier.
9872 When a variable is declared as a bit, it is allocated into the bit addressable
9873 memory of 8051, e.g.:
9881 Writing 1 to this variable generates the assembly code:
9897 The bit addressable memory consists of 128 bits which are located from 0x20
9898 to 0x2f in data memory.
9901 Apart from this 8051 specific storage class most architectures support ANSI-C
9903 \begin_inset LatexCommand \index{bitfields}
9913 Not really meant as examples, but nevertheless showing what bitfields are
9914 about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
9918 In accordance with ISO/IEC 9899 bits and bitfields without an explicit
9919 signed modifier are implemented as unsigned.
9920 \layout Subsubsection
9923 \begin_inset LatexCommand \index{sfr}
9928 \begin_inset LatexCommand \index{\_\_sfr}
9933 \begin_inset LatexCommand \index{sfr16}
9938 \begin_inset LatexCommand \index{\_\_sfr16}
9943 \begin_inset LatexCommand \index{sfr32}
9948 \begin_inset LatexCommand \index{\_\_sfr32}
9953 \begin_inset LatexCommand \index{\_\_sbit}
9958 \begin_inset LatexCommand \index{sbit}
9965 Like the bit keyword,
9967 sfr / sfr16 / sfr32 / sbit
9969 signify both a data-type and storage class, they are used to describe the
9990 variables of a 8051, eg:
9996 \begin_inset LatexCommand \index{at}
10001 \begin_inset LatexCommand \index{\_\_at}
10005 (0x80) P0;\SpecialChar ~
10006 /* special function register P0 at location 0x80 */
10010 /* 16 bit special function register combination for timer 0
10014 with the high byte at location 0x8C and the low byte at location 0x8A */
10016 __sfr16 __at (0x8C8A) TMR0;
10021 \begin_inset LatexCommand \index{at}
10026 \begin_inset LatexCommand \index{\_\_at}
10030 (0xd7) CY;\SpecialChar ~
10032 \begin_inset LatexCommand \index{Flags}
10037 \begin_inset LatexCommand \index{Carry flag}
10044 Special function registers which are located on an address dividable by
10045 8 are bit-addressable, an
10049 addresses a specific bit within these sfr.
10051 16 Bit and 32 bit special function register combinations which require a
10052 certain access order are better not declared using
10061 Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
10062 this is not guaranteed.
10067 Please note, if you use a header file which was written for another compiler
10068 then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
10074 Specifically the syntax
10077 sfr P0 = 0x80;\SpecialChar ~
10084 by SDCC to an assignment of 0x80 to a variable called P0
10087 \begin_inset Marginal
10101 Nevertheless it is possible to write header files
10102 \begin_inset LatexCommand \index{Header files}
10107 \begin_inset LatexCommand \index{Include files}
10111 which can be shared among different compilers (see section
10112 \begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}
10118 \layout Subsubsection
10121 \begin_inset LatexCommand \index{Pointer}
10125 to MCS51/DS390 specific memory spaces
10128 SDCC allows (via language extensions) pointers to explicitly point to any
10129 of the memory spaces
10130 \begin_inset LatexCommand \index{Memory model}
10135 In addition to the explicit pointers, the compiler uses (by default) generic
10136 pointers which can be used to point to any of the memory spaces.
10140 Pointer declaration examples:
10145 /* pointer physically in internal ram pointing to object in external ram
10148 __xdata unsigned char * __data p;
10152 /* pointer physically in external ram pointing to object in internal ram
10155 __data unsigned char * __xdata p;
10159 /* pointer physically in code rom pointing to data in xdata space */
10161 __xdata unsigned char * __code p;
10165 /* pointer physically in code space pointing to data in code space */
10167 __code unsigned char * __code p;
10171 /* generic pointer physically located in xdata space */
10173 unsigned char * __xdata p;
10177 /* generic pointer physically located in default memory space */
10183 /* the following is a function pointer
10184 \begin_inset LatexCommand \index{function pointer}
10188 physically located in data space */
10190 char (* __data fp)(void);
10193 Well you get the idea.
10198 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
10211 The highest order byte of the
10215 pointers contains the data space information.
10216 Assembler support routines are called whenever data is stored or retrieved
10222 These are useful for developing reusable library
10223 \begin_inset LatexCommand \index{Libraries}
10228 Explicitly specifying the pointer
10229 \begin_inset LatexCommand \index{pointer}
10233 type will generate the most efficient code.
10234 \layout Subsubsection
10236 Notes on MCS51 memory
10237 \begin_inset LatexCommand \index{MCS51 memory}
10244 The 8051 family of microcontrollers have a minimum of 128 bytes of internal
10245 RAM memory which is structured as follows:
10249 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
10252 - Bytes 20-2F - 16 bytes to hold 128 bit
10253 \begin_inset LatexCommand \index{bit}
10259 - Bytes 30-7F - 80 bytes for general purpose use.
10264 Additionally some members of the MCS51 family may have up to 128 bytes of
10265 additional, indirectly addressable, internal RAM memory (
10270 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
10275 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
10280 Furthermore, some chips may have some built in external memory (
10285 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10290 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10294 ) which should not be confused with the internal, directly addressable RAM
10300 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
10305 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
10310 Sometimes this built in
10314 memory has to be activated before using it (you can probably find this
10315 information on the datasheet of the microcontroller your are using, see
10317 \begin_inset LatexCommand \ref{sub:Startup-Code}
10325 Normally SDCC will only use the first bank
10326 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
10330 of registers (register bank 0), but it is possible to specify that other
10331 banks of registers (keyword
10338 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
10343 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
10349 ) should be used in interrupt
10350 \begin_inset LatexCommand \index{interrupt}
10355 \begin_inset LatexCommand \index{\_\_interrupt}
10360 By default, the compiler will place the stack after the last byte of allocated
10361 memory for variables.
10362 For example, if the first 2 banks of registers are used, and only four
10367 variables, it will position the base of the internal stack at address 20
10369 This implies that as the stack
10370 \begin_inset LatexCommand \index{stack}
10374 grows, it will use up the remaining register banks, and the 16 bytes used
10375 by the 128 bit variables, and 80 bytes for general purpose use.
10376 If any bit variables are used, the data variables will be placed in unused
10377 register banks and after the byte holding the last bit variable.
10378 For example, if register banks 0 and 1 are used, and there are 9 bit variables
10383 variables will be placed starting from address 0x10 to 0x20 and continue
10396 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
10400 to specify the start address of the
10415 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
10419 to specify the size of the total internal RAM (
10433 By default the 8051 linker will place the stack after the last byte of (i)data
10446 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
10450 allows you to specify the start of the stack, i.e.
10451 you could start it after any data in the general purpose area.
10452 If your microcontroller has additional indirectly addressable internal
10457 ) you can place the stack on it.
10458 You may also need to use -
10469 \begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
10473 to set the start address of the external RAM (
10488 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
10492 to specify its size.
10493 Same goes for the code memory, using -
10504 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
10519 \begin_inset LatexCommand \index{-\/-code-size <Value>}
10524 If in doubt, don't specify any options and see if the resulting memory
10525 layout is appropriate, then you can adjust it.
10527 \added_space_bottom bigskip
10528 The linker generates two files with memory allocation information.
10529 The first, with extension .map
10530 \begin_inset LatexCommand \index{<file>.map}
10534 shows all the variables and segments.
10535 The second with extension .mem
10536 \begin_inset LatexCommand \index{<file>.mem}
10540 shows the final memory layout.
10541 The linker will complain either if memory segments overlap, there is not
10542 enough memory, or there is not enough space for stack.
10543 If you get any linking warnings and/or errors related to stack or segments
10544 allocation, take a look at either the .map or .mem files to find out what
10546 The .mem file may even suggest a solution to the problem.
10549 Z80/Z180 Storage Class
10550 \begin_inset LatexCommand \index{Z80!Storage class}
10554 Language Extensions
10555 \layout Subsubsection
10558 \begin_inset LatexCommand \index{sfr}
10563 \begin_inset LatexCommand \index{\_\_sfr}
10567 (in/out to 8-bit addresses)
10571 \begin_inset LatexCommand \index{Z80}
10575 family has separate address spaces for memory and
10585 \begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
10590 \begin_inset LatexCommand \index{Z80!I/O memory}
10595 \begin_inset LatexCommand \index{Z180!I/O memory}
10599 is accessed with special instructions, e.g.:
10604 sfr at 0x78 IoPort;\SpecialChar ~
10606 /* define a var in I/O space at 78h called IoPort */
10610 Writing 0x01 to this variable generates the assembly code:
10615 3E 01\SpecialChar ~
10623 D3 78\SpecialChar ~
10630 \layout Subsubsection
10633 \begin_inset LatexCommand \index{sfr}
10638 \begin_inset LatexCommand \index{\_\_sfr}
10642 (in/out to 16-bit addresses)
10649 is used to support 16 bit addresses in I/O memory e.g.:
10655 \begin_inset LatexCommand \index{at}
10660 \begin_inset LatexCommand \index{\_\_at}
10667 Writing 0x01 to this variable generates the assembly code:
10672 01 23 01\SpecialChar ~
10677 3E 01\SpecialChar ~
10685 ED 79\SpecialChar ~
10692 \layout Subsubsection
10695 \begin_inset LatexCommand \index{sfr}
10700 \begin_inset LatexCommand \index{\_\_sfr}
10704 (in0/out0 to 8 bit addresses on Z180
10705 \begin_inset LatexCommand \index{Z180}
10710 \begin_inset LatexCommand \index{HD64180 (see Z180)}
10716 \added_space_bottom bigskip
10717 The compiler option -
10728 \begin_inset LatexCommand \index{Z180!Options!-\/-portmode}
10732 =180 (80) and a compiler #pragma\SpecialChar ~
10734 \begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}
10738 z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
10748 If you include the file z180.h this will be set automatically.
10752 \begin_inset LatexCommand \index{HC08!Storage class}
10756 Language Extensions
10757 \layout Subsubsection
10760 \begin_inset LatexCommand \index{data (hc08 storage class)}
10765 \begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
10772 The data storage class declares a variable that resides in the first 256
10773 bytes of memory (the direct page).
10775 \begin_inset LatexCommand \index{HC08}
10779 is most efficient at accessing variables (especially pointers) stored here.
10780 \layout Subsubsection
10783 \begin_inset LatexCommand \index{xdata (hc08 storage class)}
10788 \begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
10794 \added_space_bottom bigskip
10795 The xdata storage class declares a variable that can reside anywhere in
10797 This is the default if no storage class is specified.
10801 Absolute Addressing
10802 \begin_inset LatexCommand \index{Absolute addressing}
10809 Data items can be assigned an absolute address with the
10812 \begin_inset LatexCommand \index{at}
10817 \begin_inset LatexCommand \index{\_\_at}
10823 keyword, in addition to a storage class, e.g.:
10829 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10834 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10839 \begin_inset LatexCommand \index{at}
10844 \begin_inset LatexCommand \index{\_\_at}
10848 0x7ffe unsigned int chksum;
10851 or, better conforming to ISO/IEC 9899 C:
10856 __xdata __at (0x7ffe) unsigned int chksum;
10859 In the above example the variable chksum will be located at 0x7ffe and 0x7fff
10860 of the external ram.
10865 reserve any space for variables declared in this way
10866 \begin_inset Marginal
10877 (they are implemented with an equate in the assembler).
10878 Thus it is left to the programmer to make sure there are no overlaps with
10879 other variables that are declared without the absolute address.
10880 The assembler listing file (.lst
10881 \begin_inset LatexCommand \index{<file>.lst}
10885 ) and the linker output files (.rst
10886 \begin_inset LatexCommand \index{<file>.rst}
10891 \begin_inset LatexCommand \index{<file>.map}
10895 ) are good places to look for such overlaps.
10896 Variables with an absolute address are
10899 \begin_inset Marginal
10913 \begin_inset LatexCommand \index{Variable initialization}
10920 In case of memory mapped I/O devices the keyword
10924 has to be used to tell the compiler that accesses might not be removed:
10930 \begin_inset LatexCommand \index{volatile}
10935 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10940 \begin_inset LatexCommand \index{at}
10944 (0x8000) unsigned char PORTA_8255;
10947 For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
10952 \begin_inset LatexCommand \index{Aligned array}
10959 starts at a block (256 byte) boundary
10960 \begin_inset LatexCommand \index{block boundary}
10965 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
10971 Absolute addresses can be specified for variables in all storage classes,
10978 \begin_inset LatexCommand \index{bit}
10983 \begin_inset LatexCommand \index{at}
10990 The above example will allocate the variable at offset 0x02 in the bit-addressab
10992 There is no real advantage to assigning absolute addresses to variables
10993 in this manner, unless you want strict control over all the variables allocated.
10994 One possible use would be to write hardware portable code.
10995 For example, if you have a routine that uses one or more of the microcontroller
10996 I/O pins, and such pins are different for two different hardwares, you
10997 can declare the I/O pins in your routine using:
11003 \begin_inset LatexCommand \index{volatile}
11007 __bit MOSI;\SpecialChar ~
11011 /* master out, slave in */
11013 extern volatile __bit MISO;\SpecialChar ~
11017 /* master in, slave out */
11019 extern volatile __bit MCLK;\SpecialChar ~
11027 /* Input and Output of a byte on a 3-wire serial bus.
11032 If needed adapt polarity of clock, polarity of data and bit order
11037 unsigned char spi_io(unsigned char out_byte)
11061 MOSI = out_byte & 0x80;
11091 /* _asm nop _endasm; */\SpecialChar ~
11099 /* for slow peripherals */
11150 Then, someplace in the code for the first hardware you would use
11156 \begin_inset LatexCommand \index{at}
11161 \begin_inset LatexCommand \index{\_\_at}
11165 (0x80) MOSI;\SpecialChar ~
11169 /* I/O port 0, bit 0 */
11171 __bit __at (0x81) MISO;\SpecialChar ~
11175 /* I/O port 0, bit 1 */
11177 __bit __at (0x82) MCLK;\SpecialChar ~
11181 /* I/O port 0, bit 2 */
11184 Similarly, for the second hardware you would use
11189 __bit __at (0x83) MOSI;\SpecialChar ~
11193 /* I/O port 0, bit 3 */
11195 __bit __at (0x91) MISO;\SpecialChar ~
11199 /* I/O port 1, bit 1 */
11202 \begin_inset LatexCommand \index{bit}
11206 __at (0x92) MCLK;\SpecialChar ~
11210 /* I/O port 1, bit 2 */
11212 \added_space_bottom bigskip
11213 and you can use the same hardware dependent routine without changes, as
11214 for example in a library.
11215 This is somehow similar to sbit, but only one absolute address has to be
11216 specified in the whole project.
11220 \begin_inset LatexCommand \index{Parameters}
11225 \begin_inset LatexCommand \index{function parameter}
11230 \begin_inset LatexCommand \index{local variables}
11235 \begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
11242 Automatic (local) variables and parameters to functions can either be placed
11243 on the stack or in data-space.
11244 The default action of the compiler is to place these variables in the internal
11245 RAM (for small model) or external RAM (for large model).
11246 This in fact makes them similar to
11249 \begin_inset LatexCommand \index{static}
11255 so by default functions are non-reentrant
11256 \begin_inset LatexCommand \index{reentrant}
11265 They can be placed on the stack
11266 \begin_inset LatexCommand \index{stack}
11283 \begin_inset LatexCommand \index{-\/-stack-auto}
11291 #pragma\SpecialChar ~
11295 \begin_inset LatexCommand \index{\#pragma stackauto}
11302 \begin_inset LatexCommand \index{reentrant}
11308 keyword in the function declaration, e.g.:
11313 unsigned char foo(char i) __reentrant
11327 Since stack space on 8051 is limited, the
11345 option should be used sparingly.
11346 Note that the reentrant keyword just means that the parameters & local
11347 variables will be allocated to the stack, it
11351 mean that the function is register bank
11352 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
11361 \begin_inset LatexCommand \index{local variables}
11365 can be assigned storage classes and absolute
11366 \begin_inset LatexCommand \index{Absolute addressing}
11375 unsigned char foo()
11383 __xdata unsigned char i;
11396 \begin_inset LatexCommand \index{at}
11400 (0x31) unsigned char j;
11412 In the above example the variable
11416 will be allocated in the external ram,
11420 in bit addressable space and
11439 or when a function is declared as
11443 this should only be done for static variables.
11447 \begin_inset LatexCommand \index{function parameter}
11451 however are not allowed any storage class
11452 \begin_inset LatexCommand \index{Storage class}
11456 , (storage classes for parameters will be ignored), their allocation is
11457 governed by the memory model in use, and the reentrancy options.
11460 It is however allowed to use bit parameters in reentrant functions and also
11461 non-static local bit variables are supported.
11462 Efficient use is limited to 8 semi-bitregisters in bit space.
11463 They are pushed and popped to stack
11464 \begin_inset LatexCommand \index{stack}
11468 as a single byte just like the normal registers.
11472 \begin_inset LatexCommand \label{sub:Overlaying}
11477 \begin_inset LatexCommand \index{Overlaying}
11485 \begin_inset LatexCommand \index{reentrant}
11489 functions SDCC will try to reduce internal ram space usage by overlaying
11490 parameters and local variables of a function (if possible).
11491 Parameters and local variables
11492 \begin_inset LatexCommand \index{local variables}
11496 of a function will be allocated to an overlayable segment if the function
11499 no other function calls and the function is non-reentrant and the memory
11501 \begin_inset LatexCommand \index{Memory model}
11508 If an explicit storage class
11509 \begin_inset LatexCommand \index{Storage class}
11513 is specified for a local variable, it will NOT be overlayed.
11516 Note that the compiler (not the linkage editor) makes the decision for overlayin
11518 Functions that are called from an interrupt service routine
11519 \begin_inset Marginal
11529 should be preceded by a #pragma\SpecialChar ~
11531 \begin_inset LatexCommand \index{\#pragma nooverlay}
11535 if they are not reentrant.
11538 Also note that the compiler does not do any processing of inline assembler
11539 code, so the compiler might incorrectly assign local variables and parameters
11540 of a function into the overlay segment if the inline assembler code calls
11541 other c-functions that might use the overlay.
11542 In that case the #pragma\SpecialChar ~
11543 nooverlay should be used.
11546 Parameters and local variables of functions that contain 16 or 32 bit multiplica
11548 \begin_inset LatexCommand \index{Multiplication}
11553 \begin_inset LatexCommand \index{Division}
11557 will NOT be overlayed since these are implemented using external functions,
11566 \begin_inset LatexCommand \index{\#pragma nooverlay}
11572 void set_error(unsigned char errcd)
11588 void some_isr () __interrupt
11589 \begin_inset LatexCommand \index{interrupt}
11618 \added_space_bottom bigskip
11619 In the above example the parameter
11627 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
11629 not present, this could cause unpredictable runtime behavior when called
11630 from an interrupt service routine.
11631 The #pragma\SpecialChar ~
11632 nooverlay ensures that the parameters and local variables for
11633 the function are NOT overlayed.
11636 Interrupt Service Routines
11637 \begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
11644 General Information
11659 outines to be coded in C, with some extended keywords.
11664 void timer_isr (void) __interrupt (1) __using (1)
11678 The optional number following the
11681 \begin_inset LatexCommand \index{interrupt}
11686 \begin_inset LatexCommand \index{\_\_interrupt}
11692 keyword is the interrupt number this routine will service.
11693 When present, the compiler will insert a call to this routine in the interrupt
11695 \begin_inset LatexCommand \index{interrupt vector table}
11699 for the interrupt number specified.
11700 If you have multiple source files in your project, interrupt service routines
11701 can be present in any of them, but a prototype of the isr MUST be present
11702 or included in the file that contains the function
11707 The optional (8051 specific) keyword
11710 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
11715 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
11721 can be used to tell the compiler to use the specified register bank when
11722 generating code for this function.
11725 Interrupt service routines open the door for some very interesting bugs:
11726 \layout Subsubsection
11729 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}
11733 Common interrupt pitfall: variable not declared
11738 If an interrupt service routine changes variables which are accessed by
11739 other functions these variables have to be declared
11744 \begin_inset LatexCommand \index{volatile}
11750 \begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}
11755 \layout Subsubsection
11758 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}
11762 Common interrupt pitfall:
11767 If the access to these variables is not
11770 \begin_inset LatexCommand \index{atomic}
11777 the processor needs more than one instruction for the access and could
11778 be interrupted while accessing the variable) the interrupt must be disabled
11779 during the access to avoid inconsistent data.
11782 Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs and
11783 should be protected by disabling interrupts.
11784 You're not automatically on the safe side if you use 8 bit variables though.
11785 We need an example here: f.e.
11786 on the 8051 the harmless looking
11787 \begin_inset Quotes srd
11792 flags\SpecialChar ~
11797 \begin_inset Quotes sld
11806 \begin_inset Quotes srd
11811 flags\SpecialChar ~
11816 \begin_inset Quotes sld
11819 from within an interrupt routine might get lost if the interrupt occurs
11822 \begin_inset Quotes sld
11827 counter\SpecialChar ~
11832 \begin_inset Quotes srd
11835 is not atomic on the 8051 even if
11839 is located in data memory.
11841 Bugs like these are hard to reproduce and can cause a lot of trouble.
11843 \layout Subsubsection
11846 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}
11850 Common interrupt pitfall:
11855 The return address and the registers used in the interrupt service routine
11856 are saved on the stack
11857 \begin_inset LatexCommand \index{stack}
11861 so there must be sufficient stack space.
11862 If there isn't variables or registers (or even the return address itself)
11869 \begin_inset LatexCommand \index{stack overflow}
11873 is most likely to happen if the interrupt occurs during the
11874 \begin_inset Quotes sld
11878 \begin_inset Quotes srd
11881 subroutine when the stack is already in use for f.e.
11882 many return addresses.
11883 \layout Subsubsection
11886 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}
11890 Common interrupt pitfall:
11892 use of non-reentrant functions
11895 A special note here, int (16 bit) and long (32 bit) integer division
11896 \begin_inset LatexCommand \index{Division}
11901 \begin_inset LatexCommand \index{Multiplication}
11906 \begin_inset LatexCommand \index{Modulus}
11911 \begin_inset LatexCommand \index{Floating point support}
11915 operations are implemented using external support routines.
11916 If an interrupt service routine needs to do any of these operations then
11917 the support routines (as mentioned in a following section) will have to
11918 be recompiled using the
11931 \begin_inset LatexCommand \index{-\/-stack-auto}
11937 option and the source file will need to be compiled using the
11952 \begin_inset LatexCommand \index{-\/-int-long-reent}
11959 Note, the type promotion
11960 \begin_inset LatexCommand \index{type promotion}
11964 required by ANSI C can cause 16 bit routines to be used
11965 \begin_inset Marginal
11976 without the programmer being aware of it.
11980 (unsigned char)(tail-1)
11982 within the if clause in section
11983 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
11989 \added_space_bottom bigskip
11990 Calling other functions from an interrupt service routine is not recommended,
11991 avoid it if possible.
11992 Note that when some function is called from an interrupt service routine
11993 it should be preceded by a #pragma\SpecialChar ~
11995 \begin_inset LatexCommand \index{\#pragma nooverlay}
11999 if it is not reentrant.
12000 Furthermore nonreentrant functions should not be called from the main program
12001 while the interrupt service routine might be active.
12002 They also must not be called from low priority interrupt service routines
12003 while a high priority interrupt service routine might be active.
12004 You could use semaphores or make the function
12008 if all parameters are passed in registers.
12011 \begin_inset LatexCommand \ref{sub:Overlaying}
12016 about Overlaying and section
12017 \begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
12022 about Functions using private register banks.
12025 MCS51/DS390 Interrupt Service Routines
12029 \begin_inset LatexCommand \index{interrupt}
12033 numbers and the corresponding address & descriptions for the Standard 8051/8052
12035 SDCC will automatically adjust the
12036 \begin_inset LatexCommand \index{interrupt vector table}
12040 to the maximum interrupt number specified.
12046 \begin_inset Tabular
12047 <lyxtabular version="3" rows="9" columns="3">
12049 <column alignment="center" valignment="top" leftline="true" width="0in">
12050 <column alignment="left" valignment="top" leftline="true" width="0in">
12051 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
12052 <row topline="true" bottomline="true">
12053 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12061 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12069 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12078 <row topline="true">
12079 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12087 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12095 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12104 <row topline="true">
12105 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12113 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12121 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12130 <row topline="true">
12131 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12139 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12147 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12156 <row topline="true">
12157 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12165 <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">
12183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12191 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12199 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12208 <row topline="true">
12209 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12217 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12225 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12234 <row topline="true">
12235 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12243 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12250 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12259 <row topline="true" bottomline="true">
12260 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12268 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12275 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12293 If the interrupt service routine is defined without
12296 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12301 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12307 a register bank or with register bank 0 (
12311 0), the compiler will save the registers used by itself on the stack upon
12312 entry and restore them at exit, however if such an interrupt service routine
12313 calls another function then the entire register bank will be saved on the
12315 This scheme may be advantageous for small interrupt service routines which
12316 have low register usage.
12318 \added_space_bottom bigskip
12319 If the interrupt service routine is defined to be using a specific register
12324 & psw are saved and restored, if such an interrupt service routine calls
12325 another function (using another register bank) then the entire register
12326 bank of the called function will be saved on the stack
12327 \begin_inset LatexCommand \index{stack}
12332 This scheme is recommended for larger interrupt service routines.
12336 \begin_inset LatexCommand \index{HC08}
12340 Interrupt Service Routines
12342 \added_space_bottom bigskip
12343 Since the number of interrupts
12344 \begin_inset LatexCommand \index{HC08!interrupt}
12348 available is chip specific and the interrupt vector table always ends at
12349 the last byte of memory, the interrupt numbers corresponds to the interrupt
12350 vectors in reverse order of address.
12351 For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
12352 2 will use the interrupt vector at 0xfffa, and so on.
12353 However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
12354 this way; instead see section
12355 \begin_inset LatexCommand \ref{sub:Startup-Code}
12359 for details on customizing startup.
12362 Z80 Interrupt Service Routines
12366 \begin_inset LatexCommand \index{Z80}
12370 uses several different methods for determining the correct interrupt
12371 \begin_inset LatexCommand \index{Z80!interrupt}
12375 vector depending on the hardware implementation.
12376 Therefore, SDCC ignores the optional interrupt number and does not attempt
12377 to generate an interrupt vector table.
12380 By default, SDCC generates code for a maskable interrupt, which uses a RETI
12381 instruction to return from the interrupt.
12382 To write an interrupt handler for the non-maskable interrupt, which needs
12383 a RETN instruction instead, add the
12392 void nmi_isr (void) critical interrupt
12405 \added_space_bottom bigskip
12406 However if you need to create a non-interruptable interrupt service routine
12407 you would also require the
12412 To distinguish between this and an nmi_isr you must provide an interrupt
12416 Enabling and Disabling Interrupts
12419 Critical Functions and Critical Statements
12422 A special keyword may be associated with a block or a function declaring
12428 SDCC will generate code to disable all interrupts
12429 \begin_inset LatexCommand \index{interrupt}
12433 upon entry to a critical function and restore the interrupt enable to the
12434 previous state before returning.
12435 Nesting critical functions will need one additional byte on the stack
12436 \begin_inset LatexCommand \index{stack}
12445 int foo () __critical
12446 \begin_inset LatexCommand \index{critical}
12451 \begin_inset LatexCommand \index{\_\_critical}
12476 The critical attribute maybe used with other attributes like
12486 may also be used to disable interrupts more locally:
12494 More than one statement could have been included in the block.
12497 Enabling and Disabling Interrupts directly
12501 \begin_inset LatexCommand \index{interrupt}
12505 can also be disabled and enabled directly (8051):
12510 EA = 0;\SpecialChar ~
12573 EA = 1;\SpecialChar ~
12640 On other architectures which have seperate opcodes for enabling and disabling
12641 interrupts you might want to make use of defines with inline assembly
12642 \begin_inset LatexCommand \index{Assembler routines}
12647 \begin_inset LatexCommand \index{HC08!interrupt}
12657 \begin_inset LatexCommand \index{\_asm}
12666 \begin_inset LatexCommand \index{\_endasm}
12675 #define SEI _asm\SpecialChar ~
12687 Note: it is sometimes sufficient to disable only a specific interrupt source
12689 a timer or serial interrupt by manipulating an
12692 \begin_inset LatexCommand \index{interrupt mask}
12702 Usually the time during which interrupts are disabled should be kept as
12704 This minimizes both
12709 \begin_inset LatexCommand \index{interrupt latency}
12713 (the time between the occurrence of the interrupt and the execution of
12714 the first code in the interrupt routine) and
12719 \begin_inset LatexCommand \index{interrupt jitter}
12723 (the difference between the shortest and the longest interrupt latency).
12724 These really are something different, f.e.
12725 a serial interrupt has to be served before its buffer overruns so it cares
12726 for the maximum interrupt latency, whereas it does not care about jitter.
12727 On a loudspeaker driven via a digital to analog converter which is fed
12728 by an interrupt a latency of a few milliseconds might be tolerable, whereas
12729 a much smaller jitter will be very audible.
12732 You can reenable interrupts within an interrupt routine and on some architecture
12733 s you can make use of two (or more) levels of
12735 interrupt priorities
12738 \begin_inset LatexCommand \index{interrupt priority}
12743 On some architectures which don't support interrupt priorities these can
12744 be implemented by manipulating the interrupt mask and reenabling interrupts
12745 within the interrupt routine.
12746 Check there is sufficient space on the stack
12747 \begin_inset LatexCommand \index{stack}
12751 and don't add complexity unless you have to.
12756 \begin_inset LatexCommand \index{semaphore}
12760 locking (mcs51/ds390)
12763 Some architectures (mcs51/ds390) have an atomic
12764 \begin_inset LatexCommand \index{atomic}
12777 These type of instructions are typically used in preemptive multitasking
12778 systems, where a routine f.e.
12779 claims the use of a data structure ('acquires a lock
12780 \begin_inset LatexCommand \index{lock}
12784 on it'), makes some modifications and then releases the lock when the data
12785 structure is consistent again.
12786 The instruction may also be used if interrupt and non-interrupt code have
12787 to compete for a resource.
12788 With the atomic bit test and clear instruction interrupts
12789 \begin_inset LatexCommand \index{interrupt}
12793 don't have to be disabled for the locking operation.
12797 SDCC generates this instruction if the source follows this pattern:
12803 \begin_inset LatexCommand \index{volatile}
12807 bit resource_is_free;
12811 if (resource_is_free)
12821 resource_is_free=0;
12834 resource_is_free=1;
12841 Note, mcs51 and ds390 support only an atomic
12842 \begin_inset LatexCommand \index{atomic}
12850 instruction (as opposed to atomic bit test and
12855 Functions using private register banks
12856 \begin_inset LatexCommand \label{sub:Functions-using-private-banks}
12863 Some architectures have support for quickly changing register sets.
12864 SDCC supports this feature with the
12867 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12872 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12878 attribute (which tells the compiler to use a register bank
12879 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
12883 other than the default bank zero).
12884 It should only be applied to
12887 \begin_inset LatexCommand \index{interrupt}
12893 functions (see footnote below).
12894 This will in most circumstances make the generated ISR code more efficient
12895 since it will not have to save registers on the stack.
12902 attribute will have no effect on the generated code for a
12906 function (but may occasionally be useful anyway
12912 possible exception: if a function is called ONLY from 'interrupt' functions
12913 using a particular bank, it can be declared with the same 'using' attribute
12914 as the calling 'interrupt' functions.
12915 For instance, if you have several ISRs using bank one, and all of them
12916 call memcpy(), it might make sense to create a specialized version of memcpy()
12917 'using 1', since this would prevent the ISR from having to save bank zero
12918 to the stack on entry and switch to bank zero before calling the function
12925 (pending: Note, nowadays the
12929 attribute has an effect on
12933 the generated code for a
12948 function using a non-zero bank will assume that it can trash that register
12949 bank, and will not save it.
12950 Since high-priority interrupts
12951 \begin_inset LatexCommand \index{interrupts}
12956 \begin_inset LatexCommand \index{interrupt priority}
12960 can interrupt low-priority ones on the 8051 and friends, this means that
12961 if a high-priority ISR
12965 a particular bank occurs while processing a low-priority ISR
12969 the same bank, terrible and bad things can happen.
12970 To prevent this, no single register bank should be
12974 by both a high priority and a low priority ISR.
12975 This is probably most easily done by having all high priority ISRs use
12976 one bank and all low priority ISRs use another.
12977 If you have an ISR which can change priority at runtime, you're on your
12978 own: I suggest using the default bank zero and taking the small performance
12981 \added_space_bottom bigskip
12982 It is most efficient if your ISR calls no other functions.
12983 If your ISR must call other functions, it is most efficient if those functions
12984 use the same bank as the ISR (see note 1 below); the next best is if the
12985 called functions use bank zero.
12986 It is very inefficient to call a function using a different, non-zero bank
12992 \begin_inset LatexCommand \label{sub:Startup-Code}
12997 \begin_inset LatexCommand \index{Startup code}
13004 MCS51/DS390 Startup Code
13007 The compiler inserts a call to the C routine
13009 _sdcc_external_startup()
13010 \begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
13019 at the start of the CODE area.
13020 This routine is in the runtime library
13021 \begin_inset LatexCommand \index{Runtime library}
13026 By default this routine returns 0, if this routine returns a non-zero value,
13027 the static & global variable initialization will be skipped and the function
13028 main will be invoked.
13029 Otherwise static & global variables will be initialized before the function
13033 _sdcc_external_startup()
13035 routine to your program to override the default if you need to setup hardware
13036 or perform some other critical operation prior to static & global variable
13038 \begin_inset LatexCommand \index{Variable initialization}
13043 On some mcs51 variants xdata
13044 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
13048 memory has to be explicitly enabled before it can be accessed or if the
13050 \begin_inset LatexCommand \index{watchdog}
13054 needs to be disabled, this is the place to do it.
13055 The startup code clears all internal data memory, 256 bytes by default,
13056 but from 0 to n-1 if
13069 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
13076 (recommended for Chipcon CC1010).
13078 \added_space_bottom bigskip
13079 See also the compiler options
13098 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
13117 \begin_inset LatexCommand \index{-\/-main-return}
13122 \begin_inset LatexCommand \ref{sub:MCS51-variants}
13126 about MCS51-variants.
13131 \added_space_bottom bigskip
13133 \begin_inset LatexCommand \index{HC08}
13137 startup code follows the same scheme as the MCS51 startup code.
13142 \added_space_bottom bigskip
13144 \begin_inset LatexCommand \index{Z80}
13148 the startup code is inserted by linking with crt0.o which is generated from
13149 sdcc/device/lib/z80/crt0.s.
13150 If you need a different startup code you can use the compiler option
13171 \begin_inset LatexCommand \index{-\/-no-std-crt0}
13175 and provide your own crt0.o.
13179 Inline Assembler Code
13180 \begin_inset LatexCommand \index{Assembler routines}
13187 A Step by Step Introduction
13188 \begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}
13195 Starting from a small snippet of c-code this example shows for the MCS51
13196 how to use inline assembly, access variables, a function parameter and
13197 an array in xdata memory.
13198 The example uses an MCS51 here but is easily adapted for other architectures.
13199 This is a buffer routine which should be optimized:
13205 unsigned char __far
13206 \begin_inset LatexCommand \index{far (storage class)}
13211 \begin_inset LatexCommand \index{\_\_far (storage class)}
13216 \begin_inset LatexCommand \index{at}
13221 \begin_inset LatexCommand \index{\_\_at}
13225 (0x7f00) buf[0x100];
13226 \begin_inset LatexCommand \index{Aligned array}
13232 unsigned char head, tail;\SpecialChar ~
13250 \begin_inset LatexCommand \index{interrupt}
13302 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
13314 void to_buffer( unsigned char c )
13322 if( head != (unsigned char)(tail-1) )\SpecialChar ~
13328 \begin_inset LatexCommand \index{promotion to signed int}
13333 \begin_inset LatexCommand \index{type promotion}
13338 \begin_inset Marginal
13359 buf[ head++ ] = c;\SpecialChar ~
13375 /* access to a 256 byte aligned array */
13380 If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
13381 then a corresponding buffer.asm file is generated.
13382 We define a new function
13386 in file buffer.c in which we cut and paste the generated code, removing
13387 unwanted comments and some ':'.
13389 \begin_inset Quotes sld
13393 \begin_inset Quotes srd
13397 \begin_inset Quotes sld
13401 \begin_inset Quotes srd
13404 to the beginning and the end of the function body:
13410 /* With a cut and paste from the .asm file, we have something to start with.
13415 The function is not yet OK! (registers aren't saved) */
13417 void to_buffer_asm( unsigned char c )
13426 \begin_inset LatexCommand \index{\_asm}
13431 \begin_inset LatexCommand \index{\_\_asm}
13445 ;buffer.c if( head != (unsigned char)(tail-1) ) \SpecialChar ~
13451 \begin_inset LatexCommand \index{promotion to signed int}
13456 \begin_inset LatexCommand \index{type promotion}
13508 ;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
13509 \begin_inset LatexCommand \index{Aligned array}
13574 \begin_inset LatexCommand \index{\_endasm}
13579 \begin_inset LatexCommand \index{\_\_endasm}
13588 The new file buffer.c should compile with only one warning about the unreferenced
13589 function argument 'c'.
13590 Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
13591 (1) and finally have:
13597 unsigned char __far __at(0x7f00) buf[0x100];
13599 unsigned char head, tail;
13601 #define USE_ASSEMBLY (1)
13609 void to_buffer( unsigned char c )
13617 if( head != (unsigned char)(tail-1) )
13637 void to_buffer( unsigned char c )
13645 c; // to avoid warning: unreferenced function argument
13652 \begin_inset LatexCommand \index{\_asm}
13657 \begin_inset LatexCommand \index{\_\_asm}
13671 ; save used registers here.
13682 ; If we were still using r2,r3 we would have to push them here.
13685 ; if( head != (unsigned char)(tail-1) )
13728 ; we could do an ANL a,#0x0f here to use a smaller buffer (see below)
13752 ; buf[ head++ ] = c;
13763 a,dpl \SpecialChar ~
13770 ; dpl holds lower byte of function argument
13781 dpl,_head \SpecialChar ~
13784 ; buf is 0x100 byte aligned so head can be used directly
13826 ; we could do an ANL _head,#0x0f here to use a smaller buffer (see above)
13838 ; restore used registers here
13845 \begin_inset LatexCommand \index{\_endasm}
13850 \begin_inset LatexCommand \index{\_\_endasm}
13861 The inline assembler code can contain any valid code understood by the assembler
13862 , this includes any assembler directives and comment lines.
13863 The assembler does not like some characters like ':' or ''' in comments.
13864 You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
13865 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
13870 \begin_inset LatexCommand \index{Assembler documentation}
13875 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
13883 The compiler does not do any validation of the code within the
13886 \begin_inset LatexCommand \index{\_asm}
13891 \begin_inset LatexCommand \index{\_\_asm}
13899 \begin_inset LatexCommand \index{\_endasm}
13904 \begin_inset LatexCommand \index{\_\_endasm}
13913 Specifically it will not know which registers are used and thus register
13915 \begin_inset LatexCommand \index{push/pop}
13919 has to be done manually.
13923 It is recommended that each assembly instruction (including labels) be placed
13924 in a separate line (as the example shows).
13938 \begin_inset LatexCommand \index{-\/-peep-asm}
13944 command line option is used, the inline assembler code will be passed through
13945 the peephole optimizer
13946 \begin_inset LatexCommand \index{Peephole optimizer}
13951 There are only a few (if any) cases where this option makes sense, it might
13952 cause some unexpected changes in the inline assembler code.
13953 Please go through the peephole optimizer rules defined in file
13957 before using this option.
13961 \begin_inset LatexCommand \label{sub:Naked-Functions}
13966 \begin_inset LatexCommand \index{Naked functions}
13973 A special keyword may be associated with a function declaring it as
13976 \begin_inset LatexCommand \index{\_naked}
13981 \begin_inset LatexCommand \index{\_\_naked}
13992 function modifier attribute prevents the compiler from generating prologue
13993 \begin_inset LatexCommand \index{function prologue}
13998 \begin_inset LatexCommand \index{function epilogue}
14002 code for that function.
14003 This means that the user is entirely responsible for such things as saving
14004 any registers that may need to be preserved, selecting the proper register
14005 bank, generating the
14009 instruction at the end, etc.
14010 Practically, this means that the contents of the function must be written
14011 in inline assembler.
14012 This is particularly useful for interrupt functions, which can have a large
14013 (and often unnecessary) prologue/epilogue.
14014 For example, compare the code generated by these two functions:
14020 \begin_inset LatexCommand \index{volatile}
14024 data unsigned char counter;
14028 void simpleInterrupt(void) __interrupt
14029 \begin_inset LatexCommand \index{interrupt}
14034 \begin_inset LatexCommand \index{\_\_interrupt}
14052 void nakedInterrupt(void) __interrupt (2) __naked
14061 \begin_inset LatexCommand \index{\_asm}
14066 \begin_inset LatexCommand \index{\_\_asm}
14083 _counter ; does not change flags, no need to save psw
14095 ; MUST explicitly include ret or reti in _naked function.
14102 \begin_inset LatexCommand \index{\_endasm}
14107 \begin_inset LatexCommand \index{\_\_endasm}
14116 For an 8051 target, the generated simpleInterrupt looks like:
14125 example, recent versions of SDCC generate
14131 code for simpleInterrupt() and nakedInterrupt()!
14271 whereas nakedInterrupt looks like:
14286 _counter ; does not change flags, no need to save psw
14304 ; MUST explicitly include ret or reti in _naked function
14307 The related directive #pragma exclude
14308 \begin_inset LatexCommand \index{\#pragma exclude}
14312 allows a more fine grained control over pushing & popping
14313 \begin_inset LatexCommand \index{push/pop}
14320 While there is nothing preventing you from writing C code inside a
14324 function, there are many ways to shoot yourself in the foot doing this,
14325 and it is recommended that you stick to inline assembler.
14328 Use of Labels within Inline Assembler
14331 SDCC allows the use of in-line assembler with a few restrictions regarding
14333 In older versions of the compiler all labels defined within inline assembler
14342 where nnnn is a number less than 100 (which implies a limit of utmost 100
14343 inline assembler labels
14357 \begin_inset LatexCommand \index{\_asm}
14362 \begin_inset LatexCommand \index{\_\_asm}
14392 \begin_inset LatexCommand \index{\_endasm}
14397 \begin_inset LatexCommand \index{\_\_endasm}
14404 Inline assembler code cannot reference any C-Labels, however it can reference
14406 \begin_inset LatexCommand \index{Labels}
14410 defined by the inline assembler, e.g.:
14435 ; some assembler code
14455 /* some more c code */
14457 clabel:\SpecialChar ~
14459 /* inline assembler cannot reference this label */
14471 $0003: ;label (can be referenced by inline assembler only)
14478 \begin_inset LatexCommand \index{\_endasm}
14483 \begin_inset LatexCommand \index{\_\_endasm}
14493 /* some more c code */
14498 In other words inline assembly code can access labels defined in inline
14499 assembly within the scope of the function.
14500 The same goes the other way, i.e.
14501 labels defines in inline assembly can not be accessed by C statements.
14504 Interfacing with Assembler Code
14505 \begin_inset LatexCommand \index{Assembler routines}
14512 Global Registers used for Parameter Passing
14513 \begin_inset LatexCommand \index{Parameter passing}
14520 The compiler always uses the global registers
14523 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14528 \begin_inset LatexCommand \index{DPTR}
14533 \begin_inset LatexCommand \index{B (mcs51, ds390 register)}
14542 \begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}
14548 to pass the first parameter to a routine.
14549 The second parameter onwards is either allocated on the stack (for reentrant
14560 -stack-auto is used) or in data / xdata memory (depending on the memory
14565 Assembler Routine (non-reentrant)
14568 In the following example
14569 \begin_inset LatexCommand \index{reentrant}
14574 \begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
14578 the function c_func calls an assembler routine asm_func, which takes two
14580 \begin_inset LatexCommand \index{function parameter}
14589 extern int asm_func(unsigned char, unsigned char);
14593 int c_func (unsigned char i, unsigned char j)
14601 return asm_func(i,j);
14615 return c_func(10,9);
14620 The corresponding assembler function is:
14625 .globl _asm_func_PARM_2
14726 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14743 Note here that the return values
14744 \begin_inset LatexCommand \index{return value}
14748 are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
14750 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
14751 b' & 'acc' for four byte values.
14754 The parameter naming convention is _<function_name>_PARM_<n>, where n is
14755 the parameter number starting from 1, and counting from the left.
14756 The first parameter is passed in
14757 \begin_inset Quotes eld
14761 \begin_inset Quotes erd
14764 for a one byte parameter,
14765 \begin_inset Quotes eld
14769 \begin_inset Quotes erd
14773 \begin_inset Quotes eld
14777 \begin_inset Quotes erd
14780 for three bytes and
14781 \begin_inset Quotes eld
14785 \begin_inset Quotes erd
14788 for a four bytes parameter.
14789 The variable name for the second parameter will be _<function_name>_PARM_2.
14793 Assemble the assembler routine with the following command:
14800 asx8051 -losg asmfunc.asm
14807 Then compile and link the assembler routine to the C source file with the
14815 sdcc cfunc.c asmfunc.rel
14818 Assembler Routine (reentrant)
14822 \begin_inset LatexCommand \index{reentrant}
14827 \begin_inset LatexCommand \index{Assembler routines (reentrant)}
14831 the second parameter
14832 \begin_inset LatexCommand \index{function parameter}
14836 onwards will be passed on the stack, the parameters are pushed from right
14838 after the call the leftmost parameter will be on the top of the stack.
14839 Here is an example:
14844 extern int asm_func(unsigned char, unsigned char);
14848 int c_func (unsigned char i, unsigned char j) reentrant
14856 return asm_func(i,j);
14870 return c_func(10,9);
14875 The corresponding assembler routine is:
14974 \added_space_bottom bigskip
14975 The compiling and linking procedure remains the same, however note the extra
14976 entry & exit linkage required for the assembler code, _bp is the stack
14977 frame pointer and is used to compute the offset into the stack for parameters
14978 and local variables.
14982 \begin_inset LatexCommand \index{int (16 bit)}
14987 \begin_inset LatexCommand \index{long (32 bit)}
14994 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
14995 multiplication and modulus operations are implemented by support routines.
14996 These support routines are all developed in ANSI-C to facilitate porting
14997 to other MCUs, although some model specific assembler optimizations are
14999 The following files contain the described routines, all of them can be
15000 found in <installdir>/share/sdcc/lib.
15006 \begin_inset Tabular
15007 <lyxtabular version="3" rows="11" columns="2">
15009 <column alignment="left" valignment="top" leftline="true" width="0">
15010 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
15011 <row topline="true" bottomline="true">
15012 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15022 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15033 <row topline="true">
15034 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15042 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15047 16 bit multiplication
15051 <row topline="true">
15052 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15060 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15065 signed 16 bit division (calls _divuint)
15069 <row topline="true">
15070 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15078 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15083 unsigned 16 bit division
15087 <row topline="true">
15088 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15096 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15101 signed 16 bit modulus (calls _moduint)
15105 <row topline="true">
15106 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15114 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15119 unsigned 16 bit modulus
15123 <row topline="true">
15124 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15132 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15137 32 bit multiplication
15141 <row topline="true">
15142 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15150 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15155 signed 32 division (calls _divulong)
15159 <row topline="true">
15160 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15168 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15173 unsigned 32 division
15177 <row topline="true">
15178 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15186 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15191 signed 32 bit modulus (calls _modulong)
15195 <row topline="true" bottomline="true">
15196 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15204 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15209 unsigned 32 bit modulus
15222 Since they are compiled as
15227 \begin_inset LatexCommand \index{reentrant}
15232 \begin_inset LatexCommand \index{interrupt}
15236 service routines should not do any of the above operations.
15237 If this is unavoidable then the above routines will need to be compiled
15251 \begin_inset LatexCommand \index{-\/-stack-auto}
15257 option, after which the source program will have to be compiled with
15270 \begin_inset LatexCommand \index{-\/-int-long-reent}
15277 Notice that you don't have to call these routines directly.
15278 The compiler will use them automatically every time an integer operation
15282 Floating Point Support
15283 \begin_inset LatexCommand \index{Floating point support}
15290 SDCC supports IEEE (single precision 4 bytes) floating point numbers.
15291 The floating point support routines are derived from gcc's floatlib.c and
15292 consist of the following routines:
15300 \begin_inset Tabular
15301 <lyxtabular version="3" rows="17" columns="2">
15303 <column alignment="left" valignment="top" leftline="true" width="0">
15304 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
15305 <row topline="true" bottomline="true">
15306 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15323 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15332 <row topline="true">
15333 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15350 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15364 add floating point numbers
15368 <row topline="true">
15369 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15386 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15400 subtract floating point numbers
15404 <row topline="true">
15405 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15422 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15436 divide floating point numbers
15440 <row topline="true">
15441 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15458 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15472 multiply floating point numbers
15476 <row topline="true">
15477 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15494 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15508 convert floating point to unsigned char
15512 <row topline="true">
15513 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15530 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15544 convert floating point to signed char
15548 <row topline="true">
15549 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15566 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15580 convert floating point to unsigned int
15584 <row topline="true">
15585 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15602 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15616 convert floating point to signed int
15620 <row topline="true">
15621 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15647 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15661 convert floating point to unsigned long
15665 <row topline="true">
15666 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15683 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15697 convert floating point to signed long
15701 <row topline="true">
15702 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15719 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15733 convert unsigned char to floating point
15737 <row topline="true">
15738 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15755 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15769 convert char to floating point number
15773 <row topline="true">
15774 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15791 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15805 convert unsigned int to floating point
15809 <row topline="true">
15810 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15827 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15841 convert int to floating point numbers
15845 <row topline="true">
15846 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15863 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15877 convert unsigned long to floating point number
15881 <row topline="true" bottomline="true">
15882 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15899 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15913 convert long to floating point number
15925 \added_space_bottom bigskip
15926 These support routines are developed in ANSI-C so there is room for space
15927 and speed improvement
15933 These floating point routines (
15937 sinf(), cosf(), ...) for the mcs51 are implemented in assembler.
15942 Note if all these routines are used simultaneously the data space might
15944 For serious floating point usage the large model might be needed.
15945 Also notice that you don't have to call this routines directly.
15946 The compiler will use them automatically every time a floating point operation
15951 \begin_inset LatexCommand \index{Libraries}
15960 <pending: this is messy and incomplete - a little more information is in
15961 sdcc/doc/libdoc.txt
15966 Compiler support routines (_gptrget, _mulint etc.)
15969 Stdclib functions (puts, printf, strcat etc.)
15970 \layout Subsubsection
15976 \begin_inset LatexCommand \index{<stdio.h>}
15980 As usual on embedded systems you have to provide your own
15983 \begin_inset LatexCommand \index{getchar()}
15992 \begin_inset LatexCommand \index{putchar()}
15999 SDCC does not know whether the system connects to a serial line with or
16000 without handshake, LCD, keyboard or other device.
16014 You'll find examples for serial routines f.e.
16015 in sdcc/device/lib.
16021 \begin_inset LatexCommand \index{printf()}
16031 does not support float (except on ds390).
16032 To enable this recompile it with the option
16045 \begin_inset LatexCommand \index{USE\_FLOATS}
16051 on the command line.
16065 \begin_inset LatexCommand \index{-\/-model-large}
16071 for the mcs51 port, since this uses a lot of memory.
16074 If you're short on memory you might want to use
16077 \begin_inset LatexCommand \index{printf\_small()}
16092 For the mcs51 there additionally are assembly versions
16095 \begin_inset LatexCommand \index{printf\_tiny() (mcs51)}
16101 (subset of printf using less than 270 bytes) and
16104 \begin_inset LatexCommand \index{printf\_fast() (mcs51)}
16113 \begin_inset LatexCommand \index{printf\_fast\_f() (mcs51)}
16119 (floating-point aware version of printf_fast) which should fit the requirements
16120 of many embedded systems (printf_fast() can be customized by unsetting
16125 support long variables and field widths).
16126 \layout Subsubsection
16129 \begin_inset LatexCommand \index{malloc.h}
16136 As of SDCC 2.6.2 you no longer need to call an initialization routine before
16137 using dynamic memory allocation
16138 \begin_inset LatexCommand \index{dynamic memory allocation (malloc)}
16143 \begin_inset LatexCommand \index{heap (malloc)}
16147 space of 1024 bytes is provided for malloc to allocate memory from.
16148 If you need a different heap size you need to recompile _heap.c with the
16149 required size defined in HEAP_SIZE.
16150 It is recommended to make a copy of this file into your project directory
16151 and compile it there with:
16156 sdcc -c _heap.c -D HEAD_SIZE=2048
16160 And then link it with:
16165 sdcc main.rel _heap.rel
16170 Math functions (sinf, powf, sqrtf etc.)
16171 \layout Subsubsection
16176 See definitions in file <math.h>.
16183 \begin_inset LatexCommand \index{Libraries}
16187 included in SDCC should have a license at least as liberal as the GNU Lesser
16188 General Public License
16189 \begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
16200 license statements for the libraries are missing.
16201 sdcc/device/lib/ser_ir.c
16205 come with a GPL (as opposed to LGPL) License - this will not be liberal
16206 enough for many embedded programmers.
16209 If you have ported some library or want to share experience about some code
16211 falls into any of these categories Busses (I
16212 \begin_inset Formula $^{\textrm{2}}$
16215 C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
16216 cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
16217 Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list
16218 \begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}
16223 would certainly like to hear about it.
16225 \added_space_bottom bigskip
16226 Programmers coding for embedded systems are not especially famous for being
16227 enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
16228 e these references are very valuable.
16229 Let's help to create a climate where information is shared.
16235 MCS51 Memory Models
16236 \begin_inset LatexCommand \index{Memory model}
16241 \begin_inset LatexCommand \index{MCS51 memory model}
16246 \layout Subsubsection
16248 Small, Medium and Large
16251 SDCC allows three memory models for MCS51 code,
16260 Modules compiled with different memory models should
16264 be combined together or the results would be unpredictable.
16265 The library routines supplied with the compiler are compiled as small,
16267 The compiled library modules are contained in separate directories as small,
16268 medium and large so that you can link to the appropriate set.
16271 When the medium or large model is used all variables declared without a
16272 storage class will be allocated into the external ram, this includes all
16273 parameters and local variables (for non-reentrant
16274 \begin_inset LatexCommand \index{reentrant}
16279 When the small model is used variables without storage class are allocated
16280 in the internal ram.
16283 Judicious usage of the processor specific storage classes
16284 \begin_inset LatexCommand \index{Storage class}
16288 and the 'reentrant' function type will yield much more efficient code,
16289 than using the large model.
16290 Several optimizations are disabled when the program is compiled using the
16291 large model, it is therefore recommended that the small model be used unless
16292 absolutely required.
16293 \layout Subsubsection
16296 \begin_inset LatexCommand \label{sub:External-Stack}
16301 \begin_inset LatexCommand \index{stack}
16306 \begin_inset LatexCommand \index{External stack (mcs51)}
16313 The external stack (-
16324 \begin_inset LatexCommand \index{-\/-xstack}
16328 ) is located in pdata
16329 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
16333 memory (usually at the start of the external ram segment) and uses all
16334 unused space in pdata (max.
16346 -xstack option is used to compile the program, the parameters and local
16348 \begin_inset LatexCommand \index{local variables}
16352 of all reentrant functions are allocated in this area.
16353 This option is provided for programs with large stack space requirements.
16354 When used with the -
16365 \begin_inset LatexCommand \index{-\/-stack-auto}
16369 option, all parameters and local variables are allocated on the external
16370 stack (note: support libraries will need to be recompiled with the same
16372 There is a predefined target in the library makefile).
16375 The compiler outputs the higher order address byte of the external ram segment
16377 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
16382 \begin_inset LatexCommand \ref{sub:MCS51-variants}
16386 ), therefore when using the External Stack option, this port
16390 be used by the application program.
16394 \begin_inset LatexCommand \index{Memory model}
16399 \begin_inset LatexCommand \index{DS390 memory model}
16406 The only model supported is Flat 24
16407 \begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}
16412 This generates code for the 24 bit contiguous addressing mode of the Dallas
16414 In this mode, up to four meg of external RAM or code space can be directly
16416 See the data sheets at www.dalsemi.com for further information on this part.
16420 Note that the compiler does not generate any code to place the processor
16421 into 24 bitmode (although
16425 in the ds390 libraries will do that for you).
16431 \begin_inset LatexCommand \index{Tinibios (DS390)}
16435 , the boot loader or similar code must ensure that the processor is in 24
16436 bit contiguous addressing mode before calling the SDCC startup code.
16454 option, variables will by default be placed into the XDATA segment.
16459 Segments may be placed anywhere in the 4 meg address space using the usual
16471 Note that if any segments are located above 64K, the -r flag must be passed
16472 to the linker to generate the proper segment relocations, and the Intel
16473 HEX output format must be used.
16474 The -r flag can be passed to the linker by using the option
16478 on the SDCC command line.
16479 However, currently the linker can not handle code segments > 64k.
16483 \begin_inset LatexCommand \label{sec:Pragmas}
16488 \begin_inset LatexCommand \index{Pragmas}
16495 SDCC supports the following #pragma directives:
16503 \begin_inset LatexCommand \index{\#pragma save}
16507 - this will save most current options to the save/restore stack.
16508 See #pragma\SpecialChar ~
16517 \begin_inset LatexCommand \index{\#pragma restore}
16521 - will restore saved options from the last save.
16522 saves & restores can be nested.
16523 SDCC uses a save/restore stack: save pushes current options to the stack,
16524 restore pulls current options from the stack.
16525 See #pragma\SpecialChar ~
16536 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16541 \begin_inset LatexCommand \index{function prologue}
16545 function1[,function2[,function3...]] - The compiler by default uses a caller
16546 saves convention for register saving across function calls, however this
16547 can cause unnecessary register pushing & popping
16548 \begin_inset LatexCommand \index{push/pop}
16552 when calling small functions from larger functions.
16553 This option can be used to switch off the register saving convention for
16554 the function names specified.
16555 The compiler will not save registers when calling these functions, extra
16556 code need to be manually inserted at the entry & exit for these functions
16557 to save & restore the registers used by these functions, this can SUBSTANTIALLY
16558 reduce code & improve run time performance of the generated code.
16559 In the future the compiler (with inter procedural analysis) may be able
16560 to determine the appropriate scheme to use for each function call.
16571 -callee-saves command line option is used, the function names specified
16572 in #pragma\SpecialChar ~
16574 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16578 is appended to the list of functions specified in the command line.
16586 \begin_inset LatexCommand \index{\#pragma exclude}
16590 none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables the generation
16591 of pairs of push/pop
16592 \begin_inset LatexCommand \index{push/pop}
16601 \begin_inset LatexCommand \index{interrupt}
16614 The directive should be placed immediately before the ISR function definition
16615 and it affects ALL ISR functions following it.
16616 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
16617 exclude\SpecialChar ~
16619 \begin_inset LatexCommand \index{\#pragma exclude}
16624 See also the related keyword _naked
16625 \begin_inset LatexCommand \index{\_naked}
16630 \begin_inset LatexCommand \index{\_\_naked}
16642 \begin_inset LatexCommand \index{\#pragma less\_pedantic}
16646 - the compiler will not warn you anymore for obvious mistakes, you'r on
16655 \begin_inset LatexCommand \index{\#pragma disable\_warning}
16659 - the compiler will not warn you anymore about warning number <nnnn>.
16667 \begin_inset LatexCommand \index{\#pragma nogcse}
16671 - will stop global common subexpression elimination.
16679 \begin_inset LatexCommand \index{\#pragma noinduction}
16683 - will stop loop induction optimizations.
16691 \begin_inset LatexCommand \index{\#pragma noinvariant}
16695 - will not do loop invariant optimizations.
16696 For more details see Loop Invariants in section
16697 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
16709 \begin_inset LatexCommand \index{\#pragma noiv}
16713 - Do not generate interrupt
16714 \begin_inset LatexCommand \index{interrupt}
16719 \begin_inset LatexCommand \index{interrupt vector table}
16723 entries for all ISR functions defined after the pragma.
16724 This is useful in cases where the interrupt vector table must be defined
16725 manually, or when there is a secondary, manually defined interrupt vector
16727 for the autovector feature of the Cypress EZ-USB FX2).
16728 More elegantly this can be achieved by obmitting the optional interrupt
16729 number after the interrupt keyword, see section
16730 \begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}
16743 \begin_inset LatexCommand \index{\#pragma nojtbound}
16747 - will not generate code for boundary value checking, when switch statements
16748 are turned into jump-tables (dangerous).
16749 For more details see section
16750 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
16762 \begin_inset LatexCommand \index{\#pragma noloopreverse}
16766 - Will not do loop reversal optimization
16774 \begin_inset LatexCommand \index{\#pragma nooverlay}
16778 - the compiler will not overlay the parameters and local variables of a
16787 \begin_inset LatexCommand \index{\#pragma stackauto}
16802 \begin_inset LatexCommand \index{-\/-stack-auto}
16807 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
16811 Parameters and Local Variables.
16819 \begin_inset LatexCommand \index{\#pragma opt\_code\_speed}
16823 - The compiler will optimize code generation towards fast code, possibly
16824 at the expense of code size.
16825 Currently this has little effect.
16833 \begin_inset LatexCommand \index{\#pragma opt\_code\_size}
16837 - The compiler will optimize code generation towards compact code, possibly
16838 at the expense of code speed.
16839 Currently this has little effect.
16847 \begin_inset LatexCommand \index{\#pragma opt\_code\_balanced}
16851 - The compiler will attempt to generate code that is both compact and fast,
16852 as long as meeting one goal is not a detriment to the other (this is the
16862 \begin_inset LatexCommand \index{\#pragma std\_sdcc89}
16866 - Generally follow the C89 standard, but allow SDCC features that conflict
16867 with the standard (default).
16875 \begin_inset LatexCommand \index{\#pragma std\_c89}
16879 - Follow the C89 standard and disable SDCC features that conflict with the
16888 \begin_inset LatexCommand \index{\#pragma std\_sdcc99}
16892 - Generally follow the C99 standard, but allow SDCC features that conflict
16893 with the standard (incomplete support).
16901 \begin_inset LatexCommand \index{\#pragma std\_c99}
16905 - Follow the C99 standard and disable SDCC features that conflict with the
16906 standard (incomplete support).
16914 \begin_inset LatexCommand \index{\#pragma codeseg}
16918 - Use this name (max.
16919 8 characters) for the code segment.
16938 \begin_inset LatexCommand \index{\#pragma constseg}
16942 - Use this name (max.
16943 8 characters) for the const segment.
16957 The preprocessor SDCPP
16958 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
16962 supports the following #pragma directives:
16967 pedantic_parse_number
16970 \begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}
16974 (+ | -) - Pedantic parse numbers so that situations like 0xfe-LO_B(3) are
16975 parsed properly and the macro LO_B(3) gets expanded.
16977 Below is an example on how to use this pragma.
16980 Note: this functionality is not in conformance with standard!
16985 #pragma pedantic_parse_number +
16986 \begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}
16994 #define LO_B(x) ((x) & 0xff)
16998 unsigned char foo(void)
17005 unsigned char c=0xfe-LO_B(3);
17024 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
17028 (+ | -) - switch _asm _endasm block preprocessing on / off.
17030 You use this prama to define multilines of assembly code.
17031 This will prevent the preprocessor from changing the formating required
17033 Below is an example on how to use this pragma.
17038 #pragma preproc_asm -
17039 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
17045 #define MYDELAY _asm
17050 nop ;my assembly comment...
17064 #pragma preproc_asm +
17099 \begin_inset LatexCommand \index{\#pragma sdcc\_hash}
17103 (+ | -) - Allow "naked" hash in macro definition, for example:
17107 #define DIR_LO(x) #(x & 0xff)
17112 Below is an example on how to use this pragma.
17117 #pragma preproc_asm +
17119 #pragma sdcc_hash +
17120 \begin_inset LatexCommand \index{\#pragma sdcc\_hash}
17135 mov R6_B3, #(x & 0xff)
17142 mov R7_B3, #((x >> 8) & 0xff)
17166 The pragma's are intended to be used to turn-on or off certain optimizations
17167 which might cause the compiler to generate extra stack / data space to
17168 store compiler generated temporary variables.
17169 This usually happens in large functions.
17170 Pragma directives should be used as shown in the following example, they
17171 are used to control options & optimizations for a given function; pragmas
17172 should be placed before and/or after a function, placing pragma's inside
17173 a function body could have unpredictable results.
17179 \begin_inset LatexCommand \index{\#pragma save}
17190 /* save the current settings */
17193 \begin_inset LatexCommand \index{\#pragma nogcse}
17202 /* turnoff global subexpression elimination */
17204 #pragma noinduction
17205 \begin_inset LatexCommand \index{\#pragma noinduction}
17209 /* turn off induction optimizations */
17232 \begin_inset LatexCommand \index{\#pragma restore}
17236 /* turn the optimizations back on */
17239 The compiler will generate a warning message when extra space is allocated.
17240 It is strongly recommended that the save and restore pragma's be used when
17241 changing options for a function.
17250 Defines Created by the Compiler
17253 The compiler creates the following #defines
17254 \begin_inset LatexCommand \index{\#defines}
17259 \begin_inset LatexCommand \index{Defines created by the compiler}
17269 \begin_inset Tabular
17270 <lyxtabular version="3" rows="11" columns="2">
17272 <column alignment="left" valignment="top" leftline="true" width="3in">
17273 <column alignment="left" valignment="top" leftline="true" rightline="true" width="3in">
17274 <row topline="true" bottomline="true">
17275 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17285 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17296 <row topline="true">
17297 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17303 \begin_inset LatexCommand \index{SDCC}
17310 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17316 Since version 2.5.6 the version number as an int (ex.
17321 <row topline="true">
17322 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17328 \begin_inset LatexCommand \index{SDCC\_mcs51}
17333 \begin_inset LatexCommand \index{SDCC\_ds390}
17338 \begin_inset LatexCommand \index{SDCC\_z80}
17345 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17350 depending on the model used (e.g.: -mds390)
17354 <row topline="true">
17355 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17361 \begin_inset LatexCommand \index{\_\_mcs51}
17366 \begin_inset LatexCommand \index{\_\_ds390}
17371 \begin_inset LatexCommand \index{\_\_hc08}
17376 \begin_inset LatexCommand \index{\_\_z80}
17383 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17388 depending on the model used (e.g.
17393 <row topline="true">
17394 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17400 \begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
17407 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17430 <row topline="true">
17431 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17437 \begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
17444 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17467 <row topline="true">
17468 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17474 \begin_inset LatexCommand \index{SDCC\_MODEL\_MEDIUM}
17481 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17504 <row topline="true">
17505 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17511 \begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
17518 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17541 <row topline="true">
17542 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17548 \begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
17555 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17578 <row topline="true">
17579 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17585 \begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
17592 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17605 <row topline="true" bottomline="true">
17606 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17612 \begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
17619 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17639 Notes on supported Processors
17643 \begin_inset LatexCommand \label{sub:MCS51-variants}
17648 \begin_inset LatexCommand \index{MCS51 variants}
17655 MCS51 processors are available from many vendors and come in many different
17657 While they might differ considerably in respect to Special Function Registers
17658 the core MCS51 is usually not modified or is kept compatible.
17662 pdata access by SFR
17665 With the upcome of devices with internal xdata and flash memory devices
17667 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
17671 as dedicated I/O port is becoming more popular.
17672 Switching the high byte for pdata
17673 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
17677 access which was formerly done by port P2 is then achieved by a Special
17679 \begin_inset LatexCommand \index{sfr}
17684 In well-established MCS51 tradition the address of this
17688 is where the chip designers decided to put it.
17689 Needless to say that they didn't agree on a common name either.
17690 So that the startup code can correctly initialize xdata variables, you
17691 should define an sfr with the name _XPAGE
17694 \begin_inset LatexCommand \index{\_XPAGE (mcs51)}
17700 at the appropriate location if the default, port P2, is not used for this.
17706 __sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family */
17711 __sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17716 __sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17719 For more exotic implementations further customizations may be needed.
17721 \begin_inset LatexCommand \ref{sub:Startup-Code}
17725 for other possibilities.
17728 Other Features available by SFR
17730 \added_space_bottom bigskip
17731 Some MCS51 variants offer features like Double DPTR
17732 \begin_inset LatexCommand \index{DPTR}
17736 , multiple DPTR, decrementing DPTR, 16x16 Multiply.
17737 These are currently not used for the MCS51 port.
17738 If you absolutely need them you can fall back to inline assembly or submit
17744 \added_space_bottom bigskip
17746 \begin_inset LatexCommand \index{DS80C400}
17751 \begin_inset LatexCommand \index{DS400}
17755 microcontroller has a rich set of peripherals.
17756 In its built-in ROM library it includes functions to access some of the
17757 features, among them is a TCP stack with IP4 and IP6 support.
17758 Library headers (currently in beta status) and other files are provided
17762 \begin_inset LatexCommand \url{ftp://ftp.dalsemi.com/pub/tini/ds80c400/c_libraries/sdcc/index.html}
17770 The Z80 and gbz80 port
17773 SDCC can target both the Zilog Z80
17774 \begin_inset LatexCommand \index{Z80}
17778 and the Nintendo Gameboy's Z80-like gbz80
17779 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
17784 The Z80 port is passed through the same
17787 \begin_inset LatexCommand \index{Regression test}
17794 \begin_inset LatexCommand \ref{sec:Quality-control}
17798 ) as the MCS51 and DS390 ports, so floating point support, support for long
17799 variables and bitfield support is fine.
17800 See mailing lists and forums about interrupt routines.
17802 \added_space_bottom bigskip
17803 As always, the code is the authoritative reference - see z80/ralloc.c and
17806 \begin_inset LatexCommand \index{Z80!stack}
17810 frame is similar to that generated by the IAR Z80 compiler.
17811 IX is used as the base pointer, HL and IY are used as a temporary registers,
17812 and BC and DE are available for holding variables.
17814 \begin_inset LatexCommand \index{Z80!return value}
17818 for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
17820 The gbz80 port use the same set of registers for the return values, but
17821 in a different order of significance: E (one byte), DE (two bytes), or
17828 The port to the Freescale/Motorola HC08
17829 \begin_inset LatexCommand \index{HC08}
17833 family has been added in October 2003, and is still undergoing some basic
17835 The code generator is complete, but the register allocation is still quite
17837 Some of the SDCC's standard C library functions have embedded non-HC08
17838 inline assembly and so are not yet usable.
17840 \added_space_bottom bigskip
17841 The HC08 port passes the regression test suite (see section
17842 \begin_inset LatexCommand \ref{sec:Quality-control}
17853 \begin_inset LatexCommand \index{PIC14}
17857 port still requires a major effort from the development community.
17858 However it can work for simple code.
17859 It passes its (smaller set of) regression tests
17860 \begin_inset LatexCommand \index{Regression test (PIC14)}
17866 sdcc/src/regression
17871 C code and 14bit PIC code page
17872 \begin_inset LatexCommand \index{code page (pic14)}
17877 \begin_inset LatexCommand \index{RAM bank (pic14)}
17884 The linker organizes allocation for the code page and RAM banks.
17885 It does not have intimate knowledge of the code flow.
17886 It will put all the code section of a single asm file into a single code
17888 In order to make use of multiple code pages, separate asm files must be
17890 The compiler treats all functions of a single C file as being in the same
17891 code page unless it is non static.
17895 To get the best follow these guide lines:
17898 Make local functions static, as non static functions require code page selection
17902 For devices that have multiple code pages it is more efficient to use the
17903 same number of files as pages, i.e.
17904 for the 16F877 use 4 separate files and i.e.
17905 for the 16F874 use 2 separate files.
17906 This way the linker can put the code for each file into different code
17907 pages and there's less page selection overhead.
17910 And as for any 8 bit micro (especially for PIC 14 as they have a very simple
17911 instruction set), use 'unsigned char' whereever possible instead of 'int'.
17914 Creating a device include file
17917 For generating a device include file
17918 \begin_inset LatexCommand \index{PIC14!Header files}
17922 use the support perl script inc2h.pl kept in directory support/script.
17928 For the interrupt function, use the keyword '__interrupt'
17929 \begin_inset LatexCommand \index{PIC14!interrupt}
17933 with level number of 0 (PIC14 only has 1 interrupt so this number is only
17934 there to avoid a syntax error - it ought to be fixed).
17940 void Intr(void) __interrupt 0
17946 T0IF = 0; /* Clear timer interrupt */
17951 Linking and assembling
17954 For assembling you can use either GPUTILS'
17955 \begin_inset LatexCommand \index{gputils (pic tools)}
17959 gpasm.exe or MPLAB's mpasmwin.exe.
17960 GPUTILS is available from
17961 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
17966 For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
17967 If you use MPLAB and an interrupt function then the linker script file
17968 vectors section will need to be enlarged to link with mplink.
17991 sdcc -S -V -mpic14 -p16F877 $<
18005 $(PRJ).hex: $(OBJS)
18015 gplink -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS) libsdcc.lib
18037 sdcc -S -V -mpic14 -p16F877 $<
18047 mpasmwin /q /o $*.asm
18051 $(PRJ).hex: $(OBJS)
18061 mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS) libsdcc.lib
18064 Please note that indentations within a
18068 have to be done with a tabulator character.
18071 Command-line options
18074 Besides the switches common to all SDCC backends, the PIC14 port accepts
18075 the following options (for an updated list see sdcc -
18087 \labelwidthstring 00.00.0000
18100 \begin_inset LatexCommand \index{PIC14!Options!-\/-debug-extra}
18104 emit debug info in assembly output
18106 \labelwidthstring 00.00.0000
18119 \begin_inset LatexCommand \index{PIC14!Options!-\/-no-pcode-opt}
18123 disable (slightly faulty) optimization on pCode
18125 \labelwidthstring 00.00.0000
18138 \begin_inset LatexCommand \index{PIC14!Options!-\/-stack-loc}
18142 sets the lowest address of the argument passing stack (defaults to a suitably
18143 large shared databank to reduce BANKSEL overhead)
18145 \labelwidthstring 00.00.0000
18158 \begin_inset LatexCommand \index{PIC14!Options!-\/-stack-size}
18162 sets the size if the argument passing stack (default: 16, minimum: 4)
18166 \layout Subsubsection
18168 error: missing definition for symbol
18169 \begin_inset Quotes sld
18173 \begin_inset Quotes srd
18179 The PIC14 port uses library routines to provide more complex operations
18180 like multiplication, division/modulus and (generic) pointer dereferencing.
18181 In order to add these routines to your project, you must link with PIC14's
18187 For single source file projects this is done automatically, more complex
18192 to the linker's arguments.
18193 Make sure you also add an include path for the library (using the -I switch
18195 \layout Subsubsection
18197 Processor mismatch in file
18198 \begin_inset Quotes sld
18202 \begin_inset Quotes srd
18208 This warning can usually be ignored due to the very good compatibility amongst
18210 \begin_inset LatexCommand \index{PIC14}
18217 You might also consider recompiling the library for your specific device
18218 by changing the ARCH=p16f877 (default target) entry in
18220 device/lib/pic/Makefile.in
18224 device/lib/pic/Makefile
18226 to reflect your device.
18227 This might even improve performance for smaller devices as unneccesary
18228 BANKSELs migth be removed.
18232 \layout Subsubsection
18237 Currently, data can only be initialized if it resides in the source file
18243 Data in other source files will silently
18251 \begin_inset Marginal
18266 \begin_inset LatexCommand \index{PIC16}
18274 \begin_inset LatexCommand \index{PIC16}
18278 port is the portion of SDCC that is responsible to produce code for the
18280 \begin_inset LatexCommand \index{Microchip}
18284 (TM) microcontrollers with 16 bit core.
18285 Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
18286 Currently supported devices are:
18290 \begin_inset Tabular
18291 <lyxtabular version="3" rows="4" columns="6">
18293 <column alignment="center" valignment="top" leftline="true" width="0">
18294 <column alignment="center" valignment="top" leftline="true" width="0">
18295 <column alignment="center" valignment="top" leftline="true" width="0">
18296 <column alignment="center" valignment="top" leftline="true" width="0">
18297 <column alignment="center" valignment="top" leftline="true" width="0">
18298 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18299 <row topline="true">
18300 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18308 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18316 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18324 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18332 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18340 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18349 <row topline="true">
18350 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18358 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18366 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18374 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18382 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18390 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18399 <row topline="true">
18400 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18408 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18416 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18424 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18432 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18440 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18449 <row topline="true" bottomline="true">
18450 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18458 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18466 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18474 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18481 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18488 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18506 PIC16 port supports the standard command line arguments as supposed, with
18507 the exception of certain cases that will be mentioned in the following
18510 \labelwidthstring 00.00.0000
18523 \begin_inset LatexCommand \index{PIC16!Options!-\/-callee-saves}
18539 \labelwidthstring 00.00.0000
18552 \begin_inset LatexCommand \index{PIC16!Options!-\/-all-callee-saves}
18556 All function arguments are passed on stack by default.
18559 There is no need to specify this in the command line.
18561 \labelwidthstring 00.00.0000
18573 -fommit-frame-pointer
18574 \begin_inset LatexCommand \index{PIC16!Options!-\/-fommit-frame-pointer}
18578 Frame pointer will be omitted when the function uses no local variables.
18581 Port Specific Options
18582 \begin_inset LatexCommand \index{Options PIC16}
18589 The port specific options appear after the global options in the sdcc --help
18591 \layout Subsubsection
18596 General options enable certain port features and optimizations.
18598 \labelwidthstring 00.00.0000
18610 -pstack-model=[model] Used in conjuction with the command above.
18611 Defines the stack model to be used, valid stack models are :
18614 \labelwidthstring 00.00.0000
18620 Selects small stack model.
18621 8 bit stack and frame pointers.
18622 Supports 256 bytes stack size.
18624 \labelwidthstring 00.00.0000
18630 Selects large stack model.
18631 16 bit stack and frame pointers.
18632 Supports 65536 bytes stack size.
18635 \labelwidthstring 00.00.0000
18647 -preplace-udata-with=[kword] Replaces the default udata keyword for allocating
18648 unitialized data variables with [kword].
18649 Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
18651 \labelwidthstring 00.00.0000
18663 -ivt-loc <nnnn> positions the Interrupt Vector Table at location <nnnn>.
18664 Useful for bootloaders.
18666 \labelwidthstring 00.00.0000
18678 -asm= sets the full path and name of an external assembler to call.
18680 \labelwidthstring 00.00.0000
18692 -link= sets the full path and name of an external linker to call.
18694 \labelwidthstring 00.00.0000
18707 \begin_inset LatexCommand \index{PIC16!MPLAB}
18711 compatibility option.
18712 Currently only suppresses special gpasm directives.
18713 \layout Subsubsection
18715 Optimization Options
18717 \labelwidthstring 00.00.0000
18729 -optimize-goto Try to use (conditional) BRA instead of GOTO
18731 \labelwidthstring 00.00.0000
18743 -optimize-cmp Try to optimize some compares.
18745 \labelwidthstring 00.00.0000
18757 -optimize-df Analyze the dataflow of the generated code and improve it.
18759 \labelwidthstring 00.00.0000
18771 -obanksel=nn Set optimization level for inserting BANKSELs.
18776 \labelwidthstring 00.00.0000
18780 \labelwidthstring 00.00.0000
18782 1 checks previous used register and if it is the same then does not emit
18783 BANKSEL, accounts only for labels.
18785 \labelwidthstring 00.00.0000
18787 2 tries to check the location of (even different) symbols and removes BANKSELs
18788 if they are in the same bank.
18793 Important: There might be problems if the linker script has data sections
18794 across bank borders!
18796 \layout Subsubsection
18800 \labelwidthstring 00.00.0000
18812 -nodefaultlibs do not link default libraries when linking
18814 \labelwidthstring 00.00.0000
18826 -no-crt Don't link the default run-time modules
18828 \labelwidthstring 00.00.0000
18840 -use-crt= Use a custom run-time module instead of the defaults.
18841 \layout Subsubsection
18846 Debugging options enable extra debugging information in the output files.
18848 \labelwidthstring 00.00.0000
18860 -debug-xtra Similar to -
18871 \begin_inset LatexCommand \index{-\/-debug}
18875 , but dumps more information.
18877 \labelwidthstring 00.00.0000
18889 -debug-ralloc Force register allocator to dump <source>.d file with debugging
18891 <source> is the name of the file compiled.
18893 \labelwidthstring 00.00.0000
18905 -pcode-verbose Enable pcode debugging information in translation.
18907 \labelwidthstring 00.00.0000
18919 -denable-peeps Force the usage of peepholes.
18922 \labelwidthstring 00.00.0000
18934 -gstack Trace push/pops for stack pointer overflow
18936 \labelwidthstring 00.00.0000
18948 -call-tree dump call tree in .calltree file
18951 Enviromental Variables
18954 There is a number of enviromental variables that can be used when running
18955 SDCC to enable certain optimizations or force a specific program behaviour.
18956 these variables are primarily for debugging purposes so they can be enabled/dis
18960 Currently there is only two such variables available:
18962 \labelwidthstring 00.00.0000
18964 OPTIMIZE_BITFIELD_POINTER_GET when this variable exists reading of structure
18965 bitfields is optimized by directly loading FSR0 with the address of the
18966 bitfield structure.
18967 Normally SDCC will cast the bitfield structure to a bitfield pointer and
18969 This step saves data ram and code space for functions that perform heavy
18972 80 bytes of code space are saved when compiling malloc.c with this option).
18975 \labelwidthstring 00.00.0000
18977 NO_REG_OPT do not perform pCode registers optimization.
18978 This should be used for debugging purposes.
18979 In some where bugs in the pcode optimizer are found, users can benefit
18980 from temporarily disabling the optimizer until the bug is fixed.
18983 Preprocessor Macros
18987 \begin_inset LatexCommand \index{PIC16}
18991 port defines the following preprocessor macros while translating a source.
18995 \begin_inset Tabular
18996 <lyxtabular version="3" rows="6" columns="2">
18998 <column alignment="center" valignment="top" leftline="true" width="0">
18999 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19000 <row topline="true" bottomline="true">
19001 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19009 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19018 <row topline="true">
19019 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19027 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19032 Port identification
19036 <row topline="true">
19037 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19055 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19060 Port identification (same as above)
19064 <row topline="true">
19065 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19073 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19078 MCU Identification.
19083 is the microcontrol identification number, i.e.
19088 <row topline="true">
19089 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19107 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19112 MCU Identification (same as above)
19116 <row topline="true" bottomline="true">
19117 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19125 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19130 nnn = SMALL or LARGE respectively according to the stack model used
19141 In addition the following macros are defined when calling assembler:
19145 \begin_inset Tabular
19146 <lyxtabular version="3" rows="4" columns="2">
19148 <column alignment="center" valignment="top" leftline="true" width="0">
19149 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19150 <row topline="true" bottomline="true">
19151 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19159 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19168 <row topline="true">
19169 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19177 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19182 MCU Identification.
19187 is the microcontrol identification number, i.e.
19192 <row topline="true">
19193 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19201 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19206 nnn = SMALL or LARGE respectively according to the memory model used for
19211 <row topline="true" bottomline="true">
19212 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19220 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19225 nnn = SMALL or LARGE respectively according to the stack model used
19240 \begin_inset LatexCommand \index{PIC16}
19244 port uses the following directories for searching header files and libraries.
19248 \begin_inset Tabular
19249 <lyxtabular version="3" rows="3" columns="4">
19251 <column alignment="center" valignment="top" leftline="true" width="0">
19252 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19253 <column alignment="center" valignment="top" width="0">
19254 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19255 <row topline="true" bottomline="true">
19256 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19264 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19272 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19280 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19289 <row topline="true">
19290 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19295 PREFIX/sdcc/include/pic16
19298 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19303 PIC16 specific headers
19306 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19314 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19323 <row topline="true" bottomline="true">
19324 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19329 PREFIX/sdcc/lib/pic16
19332 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19337 PIC16 specific libraries
19340 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19348 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19365 \begin_inset LatexCommand \label{sub:PIC16_Pragmas}
19373 \begin_inset LatexCommand \index{PIC16}
19377 port currently supports the following pragmas:
19379 \labelwidthstring 00.00.0000
19382 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}
19387 \begin_inset LatexCommand \index{PIC16!stack}
19391 forces the code generator to initialize the stack & frame pointers at a
19393 This is an adhoc solution for cases where no STACK directive is available
19394 in the linker script or gplink is not instructed to create a stack section.
19396 The stack pragma should be used only once in a project.
19397 Multiple pragmas may result in indeterminate behaviour of the program.
19403 The old format (ie.
19404 #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
19405 cross page boundaries (or even exceed the available data RAM) and crash
19407 Make sure that stack does not cross page boundaries when using the SMALL
19413 The format is as follows:
19416 #pragma stack bottom_address [stack_size]
19423 is the lower bound of the stack section.
19424 The stack pointer initially will point at address (bottom_address+stack_size-1).
19432 /* initializes stack of 100 bytes at RAM address 0x200 */
19435 #pragma stack 0x200 100
19438 If the stack_size field is omitted then a stack is created with the default
19440 This size might be enough for most programs, but its not enough for operations
19441 with deep function nesting or excessive stack usage.
19443 \labelwidthstring 00.00.0000
19446 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}
19450 place a function symbol at static FLASH address
19458 /* place function test_func at 0x4000 */
19461 #pragma code test_func 0x4000
19465 \labelwidthstring 00.00.0000
19467 library instructs the linker to use a library module.
19472 #pragma library module_name
19479 can be any library or object file (including its path).
19480 Note that there are four reserved keywords which have special meaning.
19485 \begin_inset Tabular
19486 <lyxtabular version="3" rows="6" columns="3">
19488 <column alignment="center" valignment="top" leftline="true" width="0">
19489 <column alignment="block" valignment="top" leftline="true" width="20page%">
19490 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
19491 <row topline="true" bottomline="true">
19492 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19500 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19508 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19517 <row topline="true">
19518 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19528 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19533 ignore all library pragmas
19536 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19547 <row topline="true">
19548 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19558 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19566 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19579 <row topline="true">
19580 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19595 link the Math libarary
19598 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19611 <row topline="true">
19612 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19622 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19627 link the I/O library
19630 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19643 <row topline="true" bottomline="true">
19644 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19654 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19659 link the debug library
19662 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19681 * is the device number, i.e.
19682 452 for PIC18F452 MCU.
19685 This feature allows for linking with specific libraries withoug having to
19686 explicit name them in the command line.
19691 keyword will reject all modules specified by the library pragma.
19693 \labelwidthstring 00.00.0000
19695 udata pragma udata instructs the compiler to emit code so that linker will
19696 place a variable at a specific memory bank
19704 /* places variable foo at bank2 */
19707 #pragma udata bank2 foo
19713 In order for this pragma to work extra SECTION directives should be added
19714 in the .lkr script.
19715 In the following example a sample .lkr file is shown:
19720 // Sample linker script for the PIC18F452 processor
19726 CODEPAGE NAME=vectors START=0x0 END=0x29 PROTECTED
19729 CODEPAGE NAME=page START=0x2A END=0x7FFF
19732 CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
19735 CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
19738 CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
19741 CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED
19744 ACCESSBANK NAME=accessram START=0x0 END=0x7F
19749 DATABANK NAME=gpr0 START=0x80 END=0xFF
19752 DATABANK NAME=gpr1 START=0x100 END=0x1FF
19755 DATABANK NAME=gpr2 START=0x200 END=0x2FF
19758 DATABANK NAME=gpr3 START=0x300 END=0x3FF
19761 DATABANK NAME=gpr4 START=0x400 END=0x4FF
19764 DATABANK NAME=gpr5 START=0x500 END=0x5FF
19767 ACCESSBANK NAME=accesssfr START=0xF80 END=0xFFF PROTECTED
19772 SECTION NAME=CONFIG ROM=config
19777 SECTION NAME=bank0 RAM=gpr0 # these SECTION directives
19780 SECTION NAME=bank1 RAM=gpr1 # should be added to link
19783 SECTION NAME=bank2 RAM=gpr2 # section name 'bank?' with
19786 SECTION NAME=bank3 RAM=gpr3 # a specific DATABANK name
19789 SECTION NAME=bank4 RAM=gpr4
19792 SECTION NAME=bank5 RAM=gpr5
19795 The linker will recognise the section name set in the pragma statement and
19796 will position the variable at the memory bank set with the RAM field at
19797 the SECTION line in the linker script file.
19801 \begin_inset LatexCommand \label{sub:PIC16_Header-Files}
19808 There is one main header file
19809 \begin_inset LatexCommand \index{PIC16!Header files}
19813 that can be included to the source files using the pic16
19814 \begin_inset LatexCommand \index{PIC16}
19824 This header file contains the definitions for the processor special registers,
19825 so it is necessary if the source accesses them.
19826 It can be included by adding the following line in the beginning of the
19830 #include <pic18fregs.h>
19833 The specific microcontroller is selected within the pic18fregs.h automatically,
19834 so the same source can be used with a variety of devices.
19841 \begin_inset LatexCommand \index{PIC16!Libraries}
19846 \begin_inset LatexCommand \index{PIC16}
19850 port depends on are the microcontroller device libraries which contain
19851 the symbol definitions for the microcontroller special function registers.
19852 These libraries have the format pic18fxxxx.lib, where
19856 is the microcontroller identification number.
19857 The specific library is selected automatically by the compiler at link
19858 stage according to the selected device.
19861 Libraries are created with gplib which is part of the gputils package
19862 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
19867 \layout Subsubsection*
19869 Building the libraries
19872 Before using SDCC/pic16 there are some libraries that need to be compiled.
19873 This process is not done automatically by SDCC since not all users use
19874 SDCC for pic16 projects.
19875 So each user should compile the libraries separately.
19878 The steps to compile the pic16 libraries under Linux are:
19881 cd device/lib/pic16
19896 su -c 'make install' # install the libraries, you need the root password
19899 If you need to install the headers too, do:
19905 su -c 'make install' # install the headers, you need the root password
19908 There exist a special target to build the I/O libraries.
19909 This target is not automatically build because it will build the I/O library
19915 This way building will take quite a lot of time.
19916 Users are advised to edit the
19918 device/lib/pic16/pics.build
19920 file and then execute:
19929 The following memory models are supported by the PIC16 port:
19938 Memory model affects the default size of pointers within the source.
19939 The sizes are shown in the next table:
19943 \begin_inset Tabular
19944 <lyxtabular version="3" rows="3" columns="3">
19946 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19947 <column alignment="center" valignment="top" leftline="true" width="0">
19948 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19949 <row topline="true" bottomline="true">
19950 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19955 Pointer sizes according to memory model
19958 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19966 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19975 <row topline="true" bottomline="true">
19976 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19984 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19992 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20001 <row topline="true" bottomline="true">
20002 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20010 <cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
20018 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20034 It is advisable that all sources within a project are compiled with the
20036 If one wants to override the default memory model, this can be done by
20037 declaring a pointer as
20046 Far selects large memory model's pointers, while near selects small memory
20050 The standard device libraries (see
20051 \begin_inset LatexCommand \ref{sub:PIC16_Header-Files}
20055 ) contain no reference to pointers, so they can be used with both memory
20063 \begin_inset LatexCommand \index{PIC16!stack}
20067 implementation for the PIC16 port uses two indirect registers, FSR1 and
20070 \labelwidthstring 00.00.0000
20072 FSR1 is assigned as stack pointer
20074 \labelwidthstring 00.00.0000
20076 FSR2 is assigned as frame pointer
20079 The following stack models are supported by the PIC16 port
20100 model means that only the FSRxL byte is used to access stack and frame,
20107 uses both FSRxL and FSRxH registers.
20108 The following table shows the stack/frame pointers sizes according to stack
20109 model and the maximum space they can address:
20113 \begin_inset Tabular
20114 <lyxtabular version="3" rows="3" columns="3">
20116 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20117 <column alignment="center" valignment="top" leftline="true" width="0">
20118 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20119 <row topline="true" bottomline="true">
20120 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20125 Stack & Frame pointer sizes according to stack model
20128 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20136 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20145 <row topline="true">
20146 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20154 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20162 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20171 <row topline="true" bottomline="true">
20172 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20180 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20188 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20208 stack model is currently not working properly throughout the code generator.
20209 So its use is not advised.
20210 Also there are some other points that need special care:
20215 Do not create stack sections with size more than one physical bank (that
20219 Stack sections should no cross physical bank limits (i.e.
20220 #pragma stack 0x50 0x100)
20223 These limitations are caused by the fact that only FSRxL is modified when
20224 using SMALL stack model, so no more than 256 bytes of stack can be used.
20225 This problem will disappear after LARGE model is fully implemented.
20231 In addition to the standard SDCC function keywords, PIC16
20232 \begin_inset LatexCommand \index{PIC16}
20236 port makes available two more:
20238 \labelwidthstring 00.00.0000
20241 \begin_inset LatexCommand \index{PIC16!wparam}
20245 Use the WREG to pass one byte of the first function argument.
20246 This improves speed but you may not use this for functions with arguments
20247 that are called via function pointers, otherwise the first byte of the
20248 first parameter will get lost.
20252 void func_wparam(int a) wparam
20258 /* WREG hold the lower part of a */
20261 /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
20270 \labelwidthstring 00.00.0000
20273 \begin_inset LatexCommand \index{PIC16!shadowregs}
20277 When entering/exiting an ISR, it is possible to take advantage of the PIC18F
20278 hardware shadow registers which hold the values of WREG, STATUS and BSR
20280 This can be done by adding the keyword
20288 keyword in the function's header.
20291 void isr_shadow(void) shadowregs interrupt 1
20307 instructs the code generator not to store/restore WREG, STATUS, BSR when
20308 entering/exiting the ISR.
20311 Function return values
20314 Return values from functions are placed to the appropriate registers following
20315 a modified Microchip policy optimized for SDCC.
20316 The following table shows these registers:
20320 \begin_inset Tabular
20321 <lyxtabular version="3" rows="6" columns="2">
20323 <column alignment="center" valignment="top" leftline="true" width="0">
20324 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20325 <row topline="true" bottomline="true">
20326 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20334 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20339 destination register
20343 <row topline="true">
20344 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20352 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20361 <row topline="true">
20362 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20370 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20379 <row topline="true">
20380 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20388 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20397 <row topline="true">
20398 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20406 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20411 FSR0L:PRODH:PRODL:WREG
20415 <row topline="true" bottomline="true">
20416 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20424 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20429 on stack, FSR0 points to the beginning
20444 \begin_inset LatexCommand \index{PIC16!interrupt}
20448 service routine (ISR) is declared using the
20455 void isr(void) interrupt
20473 is the interrupt number, which for PIC18F devices can be:
20477 \begin_inset Tabular
20478 <lyxtabular version="3" rows="4" columns="3">
20480 <column alignment="center" valignment="top" leftline="true" width="0">
20481 <column alignment="center" valignment="top" leftline="true" width="0">
20482 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20483 <row topline="true" bottomline="true">
20484 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20494 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20502 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20507 Interrupt Vector Address
20511 <row topline="true">
20512 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20520 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20528 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20537 <row topline="true">
20538 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20555 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20569 HIGH priority interrupts
20572 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20581 <row topline="true" bottomline="true">
20582 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20595 LOW priority interrupts
20598 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20614 When generating assembly code for ISR the code generator places a
20620 Interrupt Vector Address
20622 which points at the genetated ISR.
20623 This single GOTO instruction is part of an automatically generated
20625 interrupt entry point
20628 The actuall ISR code is placed as normally would in the code space.
20629 Upon interrupt request, the GOTO instruction is executed which jumps to
20631 When declaring interrupt functions as _naked this GOTO instruction is
20636 The whole interrupt functions is therefore placed at the Interrupt Vector
20637 Address of the specific interrupt.
20638 This is not a problem for the LOW priority interrupts, but it is a problem
20639 for the RESET and the HIGH priority interrupts because code may be written
20640 at the next interrupt´s vector address and cause undeterminate program
20641 behaviour if that interrupt is raised.
20647 This is not a problem when
20650 this is a HIGH interrupt ISR and LOW interrupts are
20657 when the ISR is small enough not to reach the next interrupt´s vector address.
20667 is possible to be omitted.
20668 This way a function is generated similar to an ISR, but it is not assigned
20672 When entering an interrupt, currently the PIC16
20673 \begin_inset LatexCommand \index{PIC16}
20677 port automatically saves the following registers:
20689 PROD (PRODL and PRODH)
20692 FSR0 (FSR0L and FSR0H)
20695 These registers are restored upon return from the interrupt routine.
20701 NOTE that when the _naked attribute is specified for an interrupt routine,
20702 then NO registers are stored or restored.
20711 Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
20712 There are 3 types of generic pointers currently implemented data, code
20713 and eeprom pointers.
20714 They are differentiated by the value of the 7th and 6th bits of the upper
20719 \begin_inset Tabular
20720 <lyxtabular version="3" rows="5" columns="5">
20722 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20723 <column alignment="center" valignment="top" width="0">
20724 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20725 <column alignment="center" valignment="top" width="0">
20726 <column alignment="left" valignment="top" rightline="true" width="0">
20727 <row topline="true" bottomline="true">
20728 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20736 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20744 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20752 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20757 rest of the pointer
20760 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20769 <row topline="true" bottomline="true">
20770 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20778 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20786 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20794 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20803 uuuuuu uuuuxxxx xxxxxxxx
20806 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20811 a 12-bit data pointer in data RAM memory
20815 <row bottomline="true">
20816 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20824 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20832 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20840 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20849 uxxxxx xxxxxxxx xxxxxxxx
20852 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20857 a 21-bit code pointer in FLASH memory
20861 <row bottomline="true">
20862 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20870 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20878 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20886 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20895 uuuuuu uuuuuuxx xxxxxxxx
20898 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20903 a 10-bit eeprom pointer in EEPROM memory
20907 <row bottomline="true">
20908 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20916 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20924 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20932 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20941 xxxxxx xxxxxxxx xxxxxxxx
20944 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20949 unimplemented pointer type
20960 Generic pointer are read and written with a set of library functions which
20961 read/write 1, 2, 3, 4 bytes.
20965 \layout Subsubsection
20967 Standard I/O Streams
20974 the type FILE is defined as:
20977 typedef char * FILE;
20980 This type is the stream type implemented I/O in the PIC18F devices.
20981 Also the standard input and output streams are declared in stdio.h:
20984 extern FILE * stdin;
20987 extern FILE * stdout;
20990 The FILE type is actually a generic pointer which defines one more type
20991 of generic pointers, the
20996 This new type has the format:
21000 \begin_inset Tabular
21001 <lyxtabular version="3" rows="2" columns="7">
21003 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21004 <column alignment="center" valignment="top" width="0">
21005 <column alignment="center" valignment="top" leftline="true" width="0">
21006 <column alignment="center" valignment="top" leftline="true" width="0">
21007 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21008 <column alignment="center" valignment="top" width="0">
21009 <column alignment="left" valignment="top" rightline="true" width="0">
21010 <row topline="true" bottomline="true">
21011 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21019 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21027 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21035 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21043 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21051 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21056 rest of the pointer
21059 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21068 <row topline="true" bottomline="true">
21069 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21077 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21085 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21093 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21101 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21109 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21121 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21126 upper byte high nubble is 0x2n, the rest are zeroes
21137 Currently implemented there are 3 types of streams defined:
21141 \begin_inset Tabular
21142 <lyxtabular version="3" rows="4" columns="4">
21144 <column alignment="center" valignment="top" leftline="true" width="0">
21145 <column alignment="center" valignment="top" leftline="true" width="0">
21146 <column alignment="center" valignment="top" leftline="true" width="0">
21147 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21148 <row topline="true" bottomline="true">
21149 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21157 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21165 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21173 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21182 <row topline="true">
21183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21191 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21201 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21209 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21214 Writes/Reads characters via the USART peripheral
21218 <row topline="true">
21219 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21227 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21237 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21245 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21250 Writes/Reads characters via the MSSP peripheral
21254 <row topline="true" bottomline="true">
21255 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21263 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21273 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21281 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21286 Writes/Reads characters via used defined functions
21297 The stream identifiers are declared as macros in the stdio.h header.
21300 In the libc library there exist the functions that are used to write to
21301 each of the above streams.
21304 \labelwidthstring 00.00.0000
21316 _stream_usart_putchar writes a character at the USART stream
21318 \labelwidthstring 00.00.0000
21330 _stream_mssp_putchar writes a character at the MSSP stream
21332 \labelwidthstring 00.00.0000
21334 putchar dummy function.
21335 This writes a character to a user specified manner.
21338 In order to increase performance
21342 is declared in stdio.h as having its parameter in WREG (it has the wparam
21344 In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
21345 in a user-friendly way.
21350 is the name of the variable that holds the character to print.
21351 An example follows:
21354 #include <pic18fregs.h>
21366 PORTA = c; /* dump character c to PORTA */
21379 stdout = STREAM_USER; /* this is not necessary, since stdout points
21382 * by default to STREAM_USER */
21385 printf (¨This is a printf test
21393 \layout Subsubsection
21398 PIC16 contains an implementation of the printf-family of functions.
21399 There exist the following functions:
21402 extern unsigned int sprintf(char *buf, char *fmt, ...);
21405 extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
21410 extern unsigned int printf(char *fmt, ...);
21413 extern unsigned int vprintf(char *fmt, va_lista ap);
21418 extern unsigned int fprintf(FILE *fp, char *fmt, ...);
21421 extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
21424 For sprintf and vsprintf
21428 should normally be a data pointer where the resulting string will be placed.
21429 No range checking is done so the user should allocate the necessery buffer.
21430 For fprintf and vfprintf
21434 should be a stream pointer (i.e.
21435 stdout, STREAM_MSSP, etc...).
21436 \layout Subsubsection
21441 The PIC18F family of microcontrollers supports a number of interrupt sources.
21442 A list of these interrupts is shown in the following table:
21446 \begin_inset Tabular
21447 <lyxtabular version="3" rows="11" columns="4">
21449 <column alignment="left" valignment="top" leftline="true" width="0">
21450 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21451 <column alignment="left" valignment="top" leftline="true" width="0">
21452 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21453 <row topline="true" bottomline="true">
21454 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21462 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21470 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21478 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21487 <row topline="true">
21488 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21496 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21501 PORTB change interrupt
21504 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21512 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21517 EEPROM/FLASH write complete interrupt
21521 <row topline="true">
21522 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21530 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21535 INT0 external interrupt
21538 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21546 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21551 Bus collision interrupt
21555 <row topline="true">
21556 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21564 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21569 INT1 external interrupt
21572 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21580 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21585 Low voltage detect interrupt
21589 <row topline="true">
21590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21598 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21603 INT2 external interrupt
21606 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21614 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21619 Parallel slave port interrupt
21623 <row topline="true">
21624 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21632 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21637 CCP1 module interrupt
21640 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21648 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21653 AD convertion complete interrupt
21657 <row topline="true">
21658 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21666 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21671 CCP2 module interrupt
21674 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21682 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21687 USART receive interrupt
21691 <row topline="true">
21692 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21700 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21705 TMR0 overflow interrupt
21708 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21716 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21721 USART transmit interrupt
21725 <row topline="true">
21726 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21734 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21739 TMR1 overflow interrupt
21742 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21750 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21755 SSP receive/transmit interrupt
21759 <row topline="true">
21760 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21768 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21773 TMR2 matches PR2 interrupt
21776 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21783 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21791 <row topline="true" bottomline="true">
21792 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21800 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21805 TMR3 overflow interrupt
21808 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21815 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21830 The prototypes for these names are defined in the header file
21837 In order to simplify signal handling, a number of macros is provided:
21839 \labelwidthstring 00.00.0000
21841 DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
21842 high priority interrupts.
21847 is the function name to use.
21849 \labelwidthstring 00.00.0000
21851 DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
21852 low priority interrupt.
21857 is the function name to use.
21859 \labelwidthstring 00.00.0000
21861 DEF_HANDLER(sig,handler) define a handler for signal
21865 \labelwidthstring 00.00.0000
21867 END_DEF end the declaration of the dispatch table.
21870 Additionally there are two more macros to simplify the declaration of the
21873 \labelwidthstring 00.00.0000
21877 SIGHANDLER(handler)
21879 this declares the function prototype for the
21885 \labelwidthstring 00.00.0000
21887 SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
21890 An example of using the macros above is shown below:
21893 #include <pic18fregs.h>
21896 #include <signal.h>
21900 DEF_INTHIGH(high_int)
21903 DEF_HANDLER(SIG_TMR0, _tmr0_handler)
21906 DEF_HANDLER(SIG_BCOL, _bcol_handler)
21913 SIGHANDLER(_tmr0_handler)
21919 /* action to be taken when timer 0 overflows */
21926 SIGHANDLERNAKED(_bcol_handler)
21935 /* action to be taken when bus collision occurs */
21951 Special care should be taken when using the above scheme:
21954 do not place a colon (;) at the end of the DEF_* and END_DEF macros.
21957 when declaring SIGHANDLERNAKED handler never forget to use
21961 for proper returning.
21967 Here you can find some general tips for compiling programs with SDCC/pic16.
21968 \layout Subsubsection
21974 \begin_inset LatexCommand \index{PIC16!stack}
21978 size (that is 64 bytes) probably is enough for many programs.
21979 One must take care that when there are many levels of function nesting,
21980 or there is excessive usage of stack, its size should be extended.
21981 An example of such a case is the printf/sprintf family of functions.
21982 If you encounter problems like not being able to print integers, then you
21983 need to set the stack size around the maximum (256 for small stack model).
21984 The following diagram shows what happens when calling printf to print an
21988 printf () --> ltoa () --> ultoa () --> divschar ()
21991 It is should be understood that stack is easily consumed when calling complicate
21993 Using command line arguments like -
22003 -fommit-frame-pointer might reduce stack usage by not creating unnecessery
22005 Other ways to reduce stack usage may exist.
22011 The PIC16 Port currently does not pass SDCC's regression test
22012 \begin_inset LatexCommand \index{Regression test (PIC16)}
22017 \begin_inset LatexCommand \ref{sec:Quality-control}
22021 ) and thus the nightly regression tests for the PIC16 target are currently
22022 disabled for all hosts except for
22027 This means you can see the result of the PIC16 regression tests f.e.
22028 by checking the log files in
22029 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/regression_test_results/amd64-unknown-linux2.3/}
22033 (pick the most up to date file there, scroll down, lend a hand).
22039 There are several approaches to debugging your code.
22040 This chapter is meant to show your options and to give detail on some of
22045 When writing your code:
22048 write your code with debugging in mind (avoid duplicating code, put conceptually
22049 similar variables into structs, use structured code, have strategic points
22050 within your code where all variables are consistent, ...)
22053 run a syntax-checking tool like splint
22054 \begin_inset LatexCommand \index{splint (syntax checking tool)}
22059 \begin_inset LatexCommand \index{lint (syntax checking tool)}
22074 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
22081 for the high level code use a C-compiler (like f.e.
22082 GCC) to compile run and debug the code on your host.
22094 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
22098 ) on howto handle syntax extensions like __xdata, __at(), ...
22102 use another C-compiler to compile code for your target.
22103 Always an option but not recommended:) And not very likely to help you.
22104 If you seriously consider walking this path you should at least occasionally
22105 check portability of your code.
22106 Most commercial compiler vendors will offer an evaluation version so you
22107 can test compile your code or snippets of your code.
22110 Debugging on a simulator:
22113 there is a separate section about SDCDB (section
22114 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
22121 or (8051 specific) use a freeware/commercial simulator which interfaces
22123 \begin_inset LatexCommand \index{AOMF, AOMF51}
22128 \begin_inset LatexCommand \ref{OMF file}
22132 ) optionally generated by SDCC.
22135 Debugging On-target:
22138 use a MCU port pin to serially output debug data to the RS232 port of your
22140 You'll probably want some level shifting device typically involving a MAX232
22142 If the hardware serial port of the MCU is not available search for 'Software
22143 UART' in your favourite search machine.
22146 use an on-target monitor.
22147 In this context a monitor is a small program which usually accepts commands
22148 via a serial line and allows to set program counter, to single step through
22149 a program and read/write memory locations.
22150 For the 8051 good examples of monitors are paulmon and cmon51 (see section
22152 \begin_inset LatexCommand \ref{sec:Related-open-source-tools}
22159 toggle MCU port pins at strategic points within your code and use an oscilloscop
22163 digital oscilloscope
22166 \begin_inset LatexCommand \index{Oscilloscope}
22170 with deep trace memory is really helpful especially if you have to debug
22171 a realtime application.
22172 If you need to monitor more pins than your oscilloscope provides you can
22173 sometimes get away with a small R-2R network.
22174 On a single channel oscilloscope you could f.e.
22175 monitor 2 push-pull driven pins by connecting one via a 10\SpecialChar ~
22177 \begin_inset Formula $\Omega$
22180 resistor and the other one by a 5\SpecialChar ~
22182 \begin_inset Formula $\Omega$
22185 resistor to the oscilloscope probe (check output drive capability of the
22186 pins you want to monitor).
22187 If you need to monitor many more pins a
22207 \begin_inset LatexCommand \index{ICE (in circuit emulator)}
22212 Usually very expensive.
22213 And very nice to have too.
22214 And usually locks you (for years...) to the devices the ICE can emulate.
22218 use a remote debugger.
22219 In most 8-bit systems the symbol information is not available on the target,
22220 and a complete debugger is too bulky for the target system.
22221 Therefore usually a debugger on the host system connects to an on-target
22222 debugging stub which accepts only primitive commands.
22225 Terms to enter into your favourite search engine could be 'remote debugging',
22226 'gdb stub' or 'inferior debugger'.
22230 use an on target hardware debugger.
22231 Some of the more modern MCUs include hardware support for setting break
22232 points and monitoring/changing variables by using dedicated hardware pins.
22233 This facility doesn't require additional code to run on the target and
22238 doesn't affect runtime behaviour until a breakpoint is hit.
22239 For the mcs51 most hardware debuggers use the AOMF
22240 \begin_inset LatexCommand \index{AOMF, AOMF51}
22245 \begin_inset LatexCommand \ref{OMF file}
22256 if you are not familiar with any of the following terms you're likely to
22257 run into problems rather sooner than later:
22274 As an embedded programmer you
22278 to know them so why not look them up
22282 you have problems?)
22285 tell someone else about your problem (actually this is a surprisingly effective
22286 means to hunt down the bug even if the listener is not familiar with your
22288 As 'failure to communicate' is probably one of the job-induced deformations
22289 of an embedded programmer this is highly encouraged.
22292 Debugging with SDCDB
22293 \begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
22298 \begin_inset LatexCommand \index{SDCDB (debugger)}
22305 SDCC is distributed with a source level debugger
22306 \begin_inset LatexCommand \index{Debugger}
22311 The debugger uses a command line interface, the command repertoire of the
22312 debugger has been kept as close to gdb
22313 \begin_inset LatexCommand \index{gdb}
22317 (the GNU debugger) as possible.
22318 The configuration and build process is part of the standard compiler installati
22319 on, which also builds and installs the debugger in the target directory
22320 specified during configuration.
22321 The debugger allows you debug BOTH at the C source and at the ASM source
22325 Compiling for Debugging
22339 \begin_inset LatexCommand \index{-\/-debug}
22343 option must be specified for all files for which debug information is to
22345 The compiler generates a .adb file for each of these files.
22346 The linker creates the .cdb
22347 \begin_inset LatexCommand \index{<file>.cdb}
22352 \begin_inset LatexCommand \index{<file>.adb}
22356 files and the address information.
22357 This .cdb is used by the debugger.
22360 How the Debugger Works
22373 -debug option is specified the compiler generates extra symbol information
22374 some of which are put into the assembler source and some are put into the
22376 Then the linker creates the .cdb file from the individual .adb files with
22377 the address information for the symbols.
22378 The debugger reads the symbolic information generated by the compiler &
22379 the address information generated by the linker.
22380 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
22381 execution is controlled by the debugger.
22382 When a command is issued for the debugger, it translates it into appropriate
22383 commands for the simulator.
22384 (Currently SDCDM only connects to the simulator but
22389 \begin_inset LatexCommand \url{http://ec2drv.sf.net/}
22393 is an effort to connect directly to the hardware.)
22396 Starting the Debugger SDCDB
22399 The debugger can be started using the following command line.
22400 (Assume the file you are debugging has the file name foo).
22414 The debugger will look for the following files.
22417 foo.c - the source file.
22420 foo.cdb - the debugger symbol information file.
22423 foo.ihx - the Intel hex format
22424 \begin_inset LatexCommand \index{Intel hex format}
22431 SDCDB Command Line Options
22444 -directory=<source file directory> this option can used to specify the directory
22446 The debugger will look into the directory list specified for source, cdb
22448 The items in the directory list must be separated by ':', e.g.
22449 if the source files can be in the directories /home/src1 and /home/src2,
22460 -directory option should be -
22470 -directory=/home/src1:/home/src2.
22471 Note there can be no spaces in the option.
22475 -cd <directory> - change to the <directory>.
22478 -fullname - used by GUI front ends.
22481 -cpu <cpu-type> - this argument is passed to the simulator please see the
22482 simulator docs for details.
22485 -X <Clock frequency > this options is passed to the simulator please see
22486 the simulator docs for details.
22489 -s <serial port file> passed to simulator see the simulator docs for details.
22492 -S <serial in,out> passed to simulator see the simulator docs for details.
22495 -k <port number> passed to simulator see the simulator docs for details.
22498 SDCDB Debugger Commands
22501 As mentioned earlier the command interface for the debugger has been deliberatel
22502 y kept as close the GNU debugger gdb, as possible.
22503 This will help the integration with existing graphical user interfaces
22504 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
22505 If you use a graphical user interface for the debugger you can skip this
22507 \layout Subsubsection*
22509 break [line | file:line | function | file:function]
22512 Set breakpoint at specified line or function:
22521 sdcdb>break foo.c:100
22523 sdcdb>break funcfoo
22525 sdcdb>break foo.c:funcfoo
22526 \layout Subsubsection*
22528 clear [line | file:line | function | file:function ]
22531 Clear breakpoint at specified line or function:
22540 sdcdb>clear foo.c:100
22542 sdcdb>clear funcfoo
22544 sdcdb>clear foo.c:funcfoo
22545 \layout Subsubsection*
22550 Continue program being debugged, after breakpoint.
22551 \layout Subsubsection*
22556 Execute till the end of the current function.
22557 \layout Subsubsection*
22562 Delete breakpoint number 'n'.
22563 If used without any option clear ALL user defined break points.
22564 \layout Subsubsection*
22566 info [break | stack | frame | registers ]
22569 info break - list all breakpoints
22572 info stack - show the function call stack.
22575 info frame - show information about the current execution frame.
22578 info registers - show content of all registers.
22579 \layout Subsubsection*
22584 Step program until it reaches a different source line.
22585 Note: pressing <return> repeats the last command.
22586 \layout Subsubsection*
22591 Step program, proceeding through subroutine calls.
22592 \layout Subsubsection*
22597 Start debugged program.
22598 \layout Subsubsection*
22603 Print type information of the variable.
22604 \layout Subsubsection*
22609 print value of variable.
22610 \layout Subsubsection*
22615 load the given file name.
22616 Note this is an alternate method of loading file for debugging.
22617 \layout Subsubsection*
22622 print information about current frame.
22623 \layout Subsubsection*
22628 Toggle between C source & assembly source.
22629 \layout Subsubsection*
22631 ! simulator command
22634 Send the string following '!' to the simulator, the simulator response is
22636 Note the debugger does not interpret the command being sent to the simulator,
22637 so if a command like 'go' is sent the debugger can loose its execution
22638 context and may display incorrect values.
22639 \layout Subsubsection*
22646 My name is Bobby Brown"
22649 Interfacing SDCDB with DDD
22652 The screenshot was converted from png to eps with:
22653 \begin_inset Quotes sld
22656 bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
22657 \begin_inset Quotes srd
22660 which produces a pretty compact eps file which is free from compression
22664 The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
22665 as this broke the build system on Sourceforge (pdf-file was broken.
22666 pdflatex does not accept eps files).
22684 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
22690 shows a screenshot of a debugging session with DDD
22691 \begin_inset LatexCommand \index{DDD (debugger)}
22695 (Unix only) on a simulated 8032.
22696 The debugging session might not run as smoothly as the screenshot suggests.
22697 The debugger allows setting of breakpoints, displaying and changing variables,
22698 single stepping through C and assembler code.
22701 The source was compiled with
22724 -debug ddd_example.c
22737 and DDD was invoked with
22744 ddd -debugger 'sdcdb -cpu 8032 ddd_example'
22747 Interfacing SDCDB with XEmacs
22748 \begin_inset LatexCommand \index{XEmacs}
22753 \begin_inset LatexCommand \index{Emacs}
22760 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
22761 sdcdb.el and sdcdbsrc.el.
22762 These two files can be found in the $(prefix)/bin directory after the installat
22764 These files need to be loaded into XEmacs for the interface to work.
22765 This can be done at XEmacs startup time by inserting the following into
22766 your '.xemacs' file (which can be found in your HOME directory):
22772 (load-file sdcdbsrc.el)
22778 .xemacs is a lisp file so the () around the command is REQUIRED.
22779 The files can also be loaded dynamically while XEmacs is running, set the
22780 environment variable 'EMACSLOADPATH' to the installation bin directory
22781 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
22782 To start the interface enter the following command:
22796 You will prompted to enter the file name to be debugged.
22801 The command line options that are passed to the simulator directly are bound
22802 to default values in the file sdcdbsrc.el.
22803 The variables are listed below, these values maybe changed as required.
22806 sdcdbsrc-cpu-type '51
22809 sdcdbsrc-frequency '11059200
22812 sdcdbsrc-serial nil
22815 The following is a list of key mapping for the debugger interface.
22826 ;;key\SpecialChar ~
22840 binding\SpecialChar ~
22864 ;;---\SpecialChar ~
22878 -------\SpecialChar ~
22920 sdcdb-next-from-src\SpecialChar ~
22948 sdcdb-back-from-src\SpecialChar ~
22976 sdcdb-cont-from-src\SpecialChar ~
22986 SDCDB continue command
23004 sdcdb-step-from-src\SpecialChar ~
23032 sdcdb-whatis-c-sexp\SpecialChar ~
23042 SDCDB ptypecommand for data at
23109 sdcdbsrc-delete\SpecialChar ~
23123 SDCDB Delete all breakpoints if no arg
23172 given or delete arg (C-u arg x)
23190 sdcdbsrc-frame\SpecialChar ~
23205 SDCDB Display current frame if no arg,
23254 given or display frame arg
23321 sdcdbsrc-goto-sdcdb\SpecialChar ~
23331 Goto the SDCDB output buffer
23349 sdcdb-print-c-sexp\SpecialChar ~
23360 SDCDB print command for data at
23427 sdcdbsrc-goto-sdcdb\SpecialChar ~
23437 Goto the SDCDB output buffer
23455 sdcdbsrc-mode\SpecialChar ~
23471 Toggles Sdcdbsrc mode (turns it off)
23486 sdcdb-finish-from-src\SpecialChar ~
23494 SDCDB finish command
23509 sdcdb-break\SpecialChar ~
23527 Set break for line with point
23542 sdcdbsrc-mode\SpecialChar ~
23558 Toggle Sdcdbsrc mode
23573 sdcdbsrc-srcmode\SpecialChar ~
23596 Here are a few guidelines that will help the compiler generate more efficient
23597 code, some of the tips are specific to this compiler others are generally
23598 good programming practice.
23601 Use the smallest data type to represent your data-value.
23602 If it is known in advance that the value is going to be less than 256 then
23603 use an 'unsigned char' instead of a 'short' or 'int'.
23604 Please note, that ANSI C requires both signed and unsigned chars to be
23605 promoted to 'signed int'
23606 \begin_inset LatexCommand \index{promotion to signed int}
23611 \begin_inset Marginal
23622 before doing any operation.
23624 \begin_inset LatexCommand \index{type promotion}
23629 \begin_inset LatexCommand \label{type promotion}
23633 can be omitted, if the result is the same.
23634 The effect of the promotion rules together with the sign-extension is often
23641 unsigned char uc = 0xfe;
23643 if (uc * uc < 0) /* this is true! */
23662 (int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
23672 (unsigned char) -12 / (signed char) -3 = ...
23675 No, the result is not 4:
23680 (int) (unsigned char) -12 / (int) (signed char) -3 =
23682 (int) (unsigned char) 0xf4 / (int) (signed char) 0xfd =
23684 (int) 0x00f4 / (int) 0xfffd =
23686 (int) 0x00f4 / (int) 0xfffd =
23688 (int) 244 / (int) -3 =
23690 (int) -81 = (int) 0xffaf;
23693 Don't complain, that gcc gives you a different result.
23694 gcc uses 32 bit ints, while SDCC uses 16 bit ints.
23695 Therefore the results are different.
23698 \begin_inset Quotes sld
23702 \begin_inset Quotes srd
23710 If well-defined overflow characteristics are important and negative values
23711 are not, or if you want to steer clear of sign-extension problems when
23712 manipulating bits or bytes, use one of the corresponding unsigned types.
23713 (Beware when mixing signed and unsigned values in expressions, though.)
23715 Although character types (especially unsigned char) can be used as "tiny"
23716 integers, doing so is sometimes more trouble than it's worth, due to unpredicta
23717 ble sign extension and increased code size.
23721 Use unsigned when it is known in advance that the value is not going to
23723 This helps especially if you are doing division or multiplication, bit-shifting
23724 or are using an array index.
23727 NEVER jump into a LOOP.
23730 Declare the variables to be local
23731 \begin_inset LatexCommand \index{local variables}
23735 whenever possible, especially loop control variables (induction).
23738 Have a look at the assembly listing to get a
23739 \begin_inset Quotes sld
23743 \begin_inset Quotes srd
23746 for the code generation.
23749 Porting code from or to other compilers
23750 \begin_inset LatexCommand \label{sec:Porting-code-to-other-compilers}
23757 check whether endianness of the compilers differs and adapt where needed.
23760 check the device specific header files
23761 \begin_inset LatexCommand \index{Header files}
23766 \begin_inset LatexCommand \index{Include files}
23770 for compiler specific syntax.
23771 Eventually include the file <compiler.h
23772 \begin_inset LatexCommand \index{compiler.h (include file)}
23777 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}
23781 to allow using common header files.
23784 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}
23791 check whether the startup code contains the correct initialization (watchdog,
23795 check whether the sizes of short, int, long match.
23798 check if some 16 or 32 bit hardware registers require a specific addressing
23799 order (least significant or most significant byte first) and adapt if needed
23808 relate to time and not to lower/upper memory location here, so this is
23813 the same as endianness).
23816 check whether the keyword
23820 is used where needed.
23821 The compilers might differ in their optimization characteristics (as different
23822 versions of the same compiler might also use more clever optimizations
23823 this is good idea anyway).
23825 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
23832 check that the compilers are not told to supress warnings.
23835 check and convert compiler specific extensions (interrupts, memory areas,
23839 check for differences in type promotion.
23840 Especially check for math operations on
23849 For the sake of C99 compatibility SDCC will probably promote these to
23853 more often than other compilers.
23854 Eventually insert explicit casts to
23863 Also check that the ~\SpecialChar ~
23865 \begin_inset LatexCommand \index{\~\/ Operator}
23872 \begin_inset LatexCommand \index{bit}
23878 variables, use the !\SpecialChar ~
23881 \begin_inset LatexCommand \ref{type promotion}
23886 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23893 check the assembly code generated for interrupt routines (f.e.
23894 for calls to possibly non-reentrant library functions).
23897 check whether timing loops result in proper timing (or preferably consider
23898 a rewrite of the code with timer based delays instead).
23901 check for differences in printf parameters (some compilers push (va_arg
23902 \begin_inset LatexCommand \index{vararg, va\_arg}
23906 ) char variables as
23910 others push them as
23916 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23923 check the resulting memory map
23924 \begin_inset LatexCommand \index{Memory map}
23929 Usage of different memory spaces: code, stack, data (for mcs51/ds390 additional
23930 ly idata, pdata, xdata).
23931 Eventually check if unexpected library functions are included.
23935 \begin_inset LatexCommand \index{Tools}
23939 included in the distribution
23943 \begin_inset Tabular
23944 <lyxtabular version="3" rows="12" columns="3">
23946 <column alignment="left" valignment="top" leftline="true" width="0pt">
23947 <column alignment="left" valignment="top" leftline="true" width="0pt">
23948 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
23949 <row topline="true" bottomline="true">
23950 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23960 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23970 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
23981 <row topline="true">
23982 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23990 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23995 Simulator for various architectures
23998 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24007 <row topline="true">
24008 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24016 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24022 \begin_inset LatexCommand \index{Header files}
24027 \begin_inset LatexCommand \index{Include files}
24034 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24039 sdcc/support/scripts
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">
24057 header file conversion
24060 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24065 sdcc/support/scripts
24069 <row topline="true">
24070 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24078 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24086 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24104 <row topline="true">
24105 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24113 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24121 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24139 <row topline="true">
24140 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24148 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24156 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24174 <row topline="true">
24175 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24191 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24209 <row topline="true">
24210 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24218 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24226 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24244 <row topline="true">
24245 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24253 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24261 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24279 <row topline="true">
24280 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24288 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24296 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24314 <row topline="true" bottomline="true">
24315 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24323 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24329 \begin_inset LatexCommand \index{packihx (tool)}
24336 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24364 \begin_inset LatexCommand \index{Documentation}
24368 included in the distribution
24372 \begin_inset Tabular
24373 <lyxtabular version="3" rows="10" columns="2">
24375 <column alignment="block" valignment="top" leftline="true" width="40col%">
24376 <column alignment="block" valignment="top" leftline="true" rightline="true" width="60col%">
24377 <row topline="true" bottomline="true" endhead="true">
24378 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24388 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24395 Filename / Where to get
24399 <row topline="true">
24400 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24405 SDCC Compiler User Guide
24408 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24413 You're reading it right now
24425 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}
24433 <row topline="true">
24434 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24442 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24459 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/ChangeLog}
24467 <row topline="true">
24468 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24474 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
24479 \begin_inset LatexCommand \index{Assembler documentation}
24486 \begin_inset LatexCommand \index{aslink}
24491 \begin_inset LatexCommand \index{Linker documentation}
24498 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24503 sdcc/as/doc/asxhtm.html
24515 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
24523 <row topline="true">
24524 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24529 SDCC regression test
24530 \begin_inset LatexCommand \index{Regression test}
24537 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24542 sdcc/doc/test_suite_spec.pdf
24554 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}
24562 <row topline="true">
24563 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24571 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24588 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/doc/}
24596 <row topline="true">
24597 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24602 Notes on debugging with SDCDB
24603 \begin_inset LatexCommand \index{SDCDB (debugger)}
24610 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24615 sdcc/debugger/README
24627 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/debugger/README}
24635 <row topline="true">
24636 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24641 Software simulator for microcontrollers
24644 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24679 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/sim/ucsim/doc/index.html}
24687 <row topline="true">
24688 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24693 Temporary notes on the pic16
24694 \begin_inset LatexCommand \index{PIC16}
24701 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24706 sdcc/src/pic16/NOTES
24718 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/src/pic16/NOTES}
24726 <row topline="true" bottomline="true">
24727 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24732 SDCC internal documentation (debugging file format)
24735 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24770 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/cdbfileformat.pdf}
24787 Related open source tools
24788 \begin_inset LatexCommand \label{sec:Related-open-source-tools}
24793 \begin_inset LatexCommand \index{Related tools}
24801 \begin_inset Tabular
24802 <lyxtabular version="3" rows="14" columns="3">
24804 <column alignment="left" valignment="top" leftline="true" width="0pt">
24805 <column alignment="block" valignment="top" leftline="true" width="30line%">
24806 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
24807 <row topline="true" bottomline="true">
24808 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24818 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24828 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24839 <row topline="true">
24840 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24846 \begin_inset LatexCommand \index{gpsim (pic simulator)}
24853 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24861 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24867 \begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
24875 <row topline="true">
24876 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24882 \begin_inset LatexCommand \index{gputils (pic tools)}
24889 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24897 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24903 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
24911 <row topline="true">
24912 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24920 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24928 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24934 \begin_inset LatexCommand \url{http://freshmeat.net/projects/flp5/}
24942 <row topline="true">
24943 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24951 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24956 Tools for Silicon Laboratories JTAG debug adapter, partly based on SDCDB
24960 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24966 \begin_inset LatexCommand \url{http://sourceforge.net/projects/ec2drv}
24974 <row topline="true">
24975 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24981 \begin_inset LatexCommand \index{indent (source formatting tool)}
24988 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24993 Formats C source - Master of the white spaces
24996 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25002 \begin_inset LatexCommand \url{http://directory.fsf.org/GNU/indent.html}
25010 <row topline="true">
25011 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25017 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
25024 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25029 Object file conversion, checksumming, ...
25032 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25038 \begin_inset LatexCommand \url{http://sourceforge.net/projects/srecord}
25046 <row topline="true">
25047 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25053 \begin_inset LatexCommand \index{objdump (tool)}
25060 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25065 Object file conversion, ...
25068 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25073 Part of binutils (should be there anyway)
25077 <row topline="true">
25078 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25086 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25091 8051 monitor (hex up-/download, single step, disassemble)
25094 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25100 \begin_inset LatexCommand \url{http://sourceforge.net/projects/cmon51}
25108 <row topline="true">
25109 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25115 \begin_inset LatexCommand \index{doxygen (source documentation tool)}
25122 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25127 Source code documentation system
25130 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25136 \begin_inset LatexCommand \url{http://www.doxygen.org}
25144 <row topline="true">
25145 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25153 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25158 IDE (has anyone tried integrating SDCC & SDCDB? Unix only)
25161 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25167 \begin_inset LatexCommand \url{http://www.kdevelop.org}
25175 <row topline="true">
25176 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25184 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25189 8051 monitor (hex up-/download, single step, disassemble)
25192 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25198 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/paulmon2.html}
25206 <row topline="true">
25207 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25213 \begin_inset LatexCommand \index{splint (syntax checking tool)}
25220 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25225 Statically checks c sources (see
25226 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
25233 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25239 \begin_inset LatexCommand \url{http://www.splint.org}
25247 <row topline="true" bottomline="true">
25248 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25254 \begin_inset LatexCommand \index{DDD (debugger)}
25261 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25266 Debugger, serves nicely as GUI to SDCDB
25267 \begin_inset LatexCommand \index{SDCDB (debugger)}
25274 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25280 \begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
25297 Related documentation / recommended reading
25301 \begin_inset Tabular
25302 <lyxtabular version="3" rows="7" columns="3">
25304 <column alignment="left" valignment="top" leftline="true" width="0pt">
25305 <column alignment="left" valignment="top" leftline="true" width="0">
25306 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
25307 <row topline="true" bottomline="true">
25308 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25318 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25328 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25339 <row topline="true">
25340 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25357 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25363 \begin_inset LatexCommand \index{C Reference card}
25370 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25376 \begin_inset LatexCommand \url{http://refcards.com/refcards/c/index.html}
25384 <row topline="true">
25385 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25393 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25399 \begin_inset LatexCommand \index{C FAQ}
25406 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25412 \begin_inset LatexCommand \url{http://www.c-faq.com}
25420 <row topline="true">
25421 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25429 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25435 \begin_inset Quotes sld
25439 \begin_inset Quotes srd
25445 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25453 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
25461 <row topline="true">
25462 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25470 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25476 \begin_inset Quotes sld
25479 Extensions for Embedded C
25480 \begin_inset Quotes srd
25486 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25494 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1021.pdf}
25502 <row topline="true">
25503 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25510 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25515 Latest datasheet of target CPU
25518 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25527 <row topline="true" bottomline="true">
25528 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25535 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25540 Revision history of datasheet
25543 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25561 Application notes specifically for SDCC
25564 SDCC makes no claims about the completeness of this list and about up-to-datenes
25565 s or correctness of the application notes
25566 \begin_inset LatexCommand \index{Application notes}
25576 \begin_inset Tabular
25577 <lyxtabular version="3" rows="7" columns="3">
25579 <column alignment="block" valignment="top" leftline="true" width="17col%">
25580 <column alignment="block" valignment="top" leftline="true" width="27col%">
25581 <column alignment="block" valignment="top" leftline="true" rightline="true" width="57col%">
25582 <row topline="true" bottomline="true">
25583 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25594 <cell alignment="left" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
25605 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25617 <row topline="true">
25618 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25628 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25635 Using the SDCC Compiler for the DS80C400
25636 \begin_inset LatexCommand \index{DS80C400}
25643 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25651 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3346.pdf}
25659 <row topline="true">
25660 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25670 <cell multicolumn="1" alignment="left" valignment="top" topline="true" leftline="true" usebox="none" width="30line%">
25677 Using the Free SDCC C Compiler to Develop Firmware for the DS89C420/430/440/450
25678 \begin_inset LatexCommand \index{DS89C4x0}
25682 Family of Microcontrollers
25685 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25693 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3477.pdf}
25701 <row topline="true">
25702 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25709 Silicon Laboratories / Cygnal
25712 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25719 Integrating SDCC 8051 Tools Into The Silicon Labs IDE
25720 \begin_inset LatexCommand \index{IDE}
25727 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25735 \begin_inset LatexCommand \url{http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/en/an198.pdf}
25743 <row topline="true">
25744 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25751 Ramtron / Goal Semiconductor
25754 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25761 Interfacing SDCC to Syn and Textpad
25764 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25772 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25780 <row topline="true">
25781 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25788 Ramtron / Goal Semiconductor
25791 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25798 Installing and Configuring SDCC and Crimson Editor
25801 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25809 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25817 <row topline="true" bottomline="true">
25818 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25828 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25835 MSC12xx Programming with SDCC
25838 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25846 \begin_inset LatexCommand \url{http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sbaa109&fileType=pdf}
25864 Some questions answered, some pointers given - it might be time to in turn
25872 can you solve your project with the selected microcontroller? Would you
25873 find out early or rather late that your target is too small/slow/whatever?
25874 Can you switch to a slightly better device if it doesn't fit?
25877 should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
25878 and/or another programming language be more adequate? Would an operating
25879 system on the target device help?
25882 if you solved the problem, will the marketing department be happy?
25885 if the marketing department is happy, will customers be happy?
25888 if you're the project manager, marketing department and maybe even the customer
25889 in one person, have you tried to see the project from the outside?
25892 is the project done if you think it is done? Or is just that other interface/pro
25893 tocol/feature/configuration/option missing? How about website, manual(s),
25894 internationali(z|s)ation, packaging, labels, 2nd source for components,
25895 electromagnetic compatability/interference, documentation for production,
25896 production test software, update mechanism, patent issues?
25899 is your project adequately positioned in that magic triangle: fame, fortune,
25903 Maybe not all answers to these questions are known and some answers may
25908 , nevertheless knowing these questions may help you to avoid burnout
25914 burnout is bad for electronic devices, programmers and motorcycle tyres
25918 Chances are you didn't want to hear some of them...
25922 \begin_inset LatexCommand \index{Support}
25929 SDCC has grown to be a large project.
25930 The compiler alone (without the preprocessor, assembler and linker) is
25931 well over 150,000 lines of code (blank stripped).
25932 The open source nature of this project is a key to its continued growth
25934 You gain the benefit and support of many active software developers and
25936 Is SDCC perfect? No, that's why we need your help.
25937 The developers take pride in fixing reported bugs.
25938 You can help by reporting the bugs and helping other SDCC users.
25939 There are lots of ways to contribute, and we encourage you to take part
25940 in making SDCC a great software package.
25944 The SDCC project is hosted on the SDCC sourceforge site at
25945 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
25950 You'll find the complete set of mailing lists
25951 \begin_inset LatexCommand \index{Mailing list(s)}
25955 , forums, bug reporting system, patch submission
25956 \begin_inset LatexCommand \index{Patch submission}
25961 \begin_inset LatexCommand \index{download}
25965 area and Subversion code repository
25966 \begin_inset LatexCommand \index{Subversion code repository}
25974 \begin_inset LatexCommand \index{Bug reporting}
25979 \begin_inset LatexCommand \index{Reporting bugs}
25986 The recommended way of reporting bugs is using the infrastructure of the
25988 You can follow the status of bug reports there and have an overview about
25992 Bug reports are automatically forwarded to the developer mailing list and
25993 will be fixed ASAP.
25994 When reporting a bug, it is very useful to include a small test program
25995 (the smaller the better) which reproduces the problem.
25996 If you can isolate the problem by looking at the generated assembly code,
25997 this can be very helpful.
25998 Compiling your program with the -
26009 \begin_inset LatexCommand \index{-\/-dumpall}
26013 option can sometimes be useful in locating optimization problems.
26014 When reporting a bug please make sure you:
26017 Attach the code you are compiling with SDCC.
26021 Specify the exact command you use to run SDCC, or attach your Makefile.
26025 Specify the SDCC version (type "
26031 "), your platform, and operating system.
26035 Provide an exact copy of any error message or incorrect output.
26039 Put something meaningful in the subject of your message.
26042 Please attempt to include these 5 important parts, as applicable, in all
26043 requests for support or when reporting any problems or bugs with SDCC.
26044 Though this will make your message lengthy, it will greatly improve your
26045 chance that SDCC users and developers will be able to help you.
26046 Some SDCC developers are frustrated by bug reports without code provided
26047 that they can use to reproduce and ultimately fix the problem, so please
26048 be sure to provide sample code if you are reporting a bug!
26051 Please have a short check that you are using a recent version of SDCC and
26052 the bug is not yet known.
26053 This is the link for reporting bugs:
26054 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
26059 With SDCC on average having more than 200 downloads
26060 \begin_inset LatexCommand \index{download}
26064 on sourceforge per day
26070 220 daily downloads on average Jan-Sept 2006 and about 150 daily downloads
26071 between 2002 and 2005.
26072 This does not include other methods of distribution.
26075 there must be some users.
26076 So it's not exactly easy to find a new bug.
26077 If you find one we need it:
26079 reporting bugs is good
26084 Requesting Features
26085 \begin_inset LatexCommand \label{sub:Requesting-Features}
26090 \begin_inset LatexCommand \index{Feature request}
26095 \begin_inset LatexCommand \index{Requesting features}
26102 Like bug reports feature requests are forwarded to the developer mailing
26104 This is the link for requesting features:
26105 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
26115 Like bug reports contributed patches are forwarded to the developer mailing
26117 This is the link for submitting patches
26118 \begin_inset LatexCommand \index{Patch submission}
26123 \begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}
26130 You need to specify some parameters to the
26134 command for the patches to be useful.
26135 If you modified more than one file a patch created f.e.
26140 \begin_inset Quotes sld
26143 diff -Naur unmodified_directory modified_directory >my_changes.patch
26144 \begin_inset Quotes srd
26150 will be fine, otherwise
26154 \begin_inset Quotes sld
26157 diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
26158 \begin_inset Quotes srd
26171 These links should take you directly to the
26172 \begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
26182 Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
26183 automated messages (mid 2003)
26187 \begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
26192 \begin_inset LatexCommand \index{Mailing list(s)}
26196 and forums are archived and searchable so if you are lucky someone already
26197 had a similar problem.
26198 While mails to the lists themselves are delivered promptly their web front
26199 end on sourceforge sometimes shows a severe time lag (up to several weeks),
26200 if you're seriously using SDCC please consider subscribing to the lists.
26206 You can follow the status of the Subversion version
26207 \begin_inset LatexCommand \index{version}
26211 of SDCC by watching the Changelog
26212 \begin_inset LatexCommand \index{Changelog}
26216 in the Subversion repository
26219 \begin_inset LatexCommand \htmlurl{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}
26226 Subversion Source Code Repository
26235 or the filenames of the snapshot versions of SDCC include date and its
26237 \begin_inset LatexCommand \index{Subversion code repository}
26242 Subversion allows to download the source of recent or previous versions
26244 \begin_inset LatexCommand \url{http://sourceforge.net/svn/?group_id=599}
26248 (by number or by date).
26249 An on-line source code browser and detailled instructions are also available
26251 SDCC versions starting from 1999 up to now are available (currently the
26252 versions prior to the conversion from cvs
26253 \begin_inset LatexCommand \index{cvs|see{Subversion}}
26257 to Subversion (April 2006) are either by accessible by Subversion or by
26262 \begin_inset LatexCommand \index{Release policy}
26269 Historically there often were long delays between official releases and
26270 the sourceforge download area tends to get not updated at all.
26271 Excuses in the past might have referred to problems with live range analysis,
26272 but as this was fixed a while ago, the current problem is that another
26273 excuse has to be found.
26274 Kidding aside, we have to get better there! On the other hand there are
26275 daily snapshots available at
26276 \begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
26280 , and you can always build the very last version (hopefully with many bugs
26281 fixed, and features added) from the source code available at
26282 \begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
26288 \begin_inset LatexCommand \index{wiki}
26293 \begin_inset LatexCommand \index{Release wiki}
26298 \begin_inset LatexCommand \url{http://sdcc.sf.net/release_wiki/}
26302 also holds some information about past and future releases.
26306 \begin_inset LatexCommand \index{Examples}
26313 You'll find some small examples in the directory
26315 sdcc/device/examples/.
26318 More examples and libraries are available at
26320 The SDCC Open Knowledge Resource
26321 \begin_inset LatexCommand \url{http://sdccokr.dl9sec.de/}
26328 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}
26335 I did insert a reference to Paul's web site here although it seems rather
26336 dedicated to a specific 8032 board (I think it's okay because it f.e.
26337 shows LCD/Harddisc interface and has a free 8051 monitor.
26338 Independent 8032 board vendors face hard competition of heavily subsidized
26339 development boards anyway).
26342 Maybe we should include some links to real world applications.
26343 Preferably pointer to pointers (one for each architecture) so this stays
26348 \begin_inset LatexCommand \label{sec:Quality-control}
26353 \begin_inset LatexCommand \index{Quality control}
26360 The compiler is passed through nightly compile and build checks.
26366 \begin_inset LatexCommand \index{Regression test}
26370 check that SDCC itself compiles flawlessly on several host platforms (i386,
26371 Opteron, 64 bit Alpha, ppc64, MacOS X on PPC, Solaris on Sparc) and checks
26372 the quality of the code generated by SDCC by running the code for several
26373 target platforms through simulators.
26374 The regression test suite comprises more than 100 files which expand to
26375 more than 500 test cases which include more than 4500 tests.
26376 The results of these tests are published daily on SDCC's snapshot page
26377 (click on the red or green symbols on the right side of
26378 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
26385 There is a separate document
26388 \begin_inset LatexCommand \index{Test suite}
26395 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}
26399 about the regression test suite.
26402 You'll find the test code in the directory
26404 sdcc/support/regression
26407 You can run these tests manually by running
26411 in this directory (or f.e.
26416 \begin_inset Quotes sld
26420 \begin_inset Quotes srd
26426 if you don't want to run the complete tests).
26427 The test code might also be interesting if you want to look for examples
26428 \begin_inset LatexCommand \index{Examples}
26432 checking corner cases of SDCC or if you plan to submit patches
26433 \begin_inset LatexCommand \index{Patch submission}
26440 The 14bit pic port uses a different set of regression tests
26441 \begin_inset LatexCommand \index{Regression test (PIC14)}
26445 , you'll find them in the directory
26447 sdcc/src/regression
26452 Use of SDCC in Education
26465 the phrase "use in education" might evoke the association "
26469 fit for use in education".
26470 This connotation is not intended but nevertheless risked as the licensing
26471 of SDCC makes it difficult to offer educational discounts
26475 If your rationales are to:
26478 give students a chance to understand the
26482 steps of code generation
26485 have a curriculum that can be extended for years.
26486 Then you could use an fpga board as target and your curriculum will seamlessly
26487 extend from logic synthesis (
26488 \begin_inset LatexCommand \url[http://www.opencores.org]{opencores.org}
26493 \begin_inset LatexCommand \url[Oregano]{http://www.oregano.at/ip/ip01.htm}
26497 ), over assembly programming, to C to FPGA compilers (
26498 \begin_inset LatexCommand \url[FPGAC]{http://sf.net/projects/fpgac}
26505 be able to insert excursions about skills like using a revision control
26506 system, submitting/applying patches, using a type-setting (as opposed to
26507 word-processing) engine LyX/LaTeX, using
26508 \begin_inset LatexCommand \url[SourceForge]{http://www.sf.net}
26513 \begin_inset LatexCommand \url[netiquette]{http://en.wikipedia.org/wiki/Netiquette}
26517 , understanding BSD/LGPL/GPL/Proprietary licensing, growth models of Open
26518 Source Software, CPU simulation, compiler regression tests
26519 \begin_inset LatexCommand \index{Regression test}
26526 And if there should be a shortage of ideas then you can always point students
26527 to the ever-growing feature request list
26528 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
26535 not tie students to a specific host platform and instead allow them to use
26540 choice (among them Alpha, i386, i386_64, MacOs, Mips, Sparc, Windows and
26542 \begin_inset LatexCommand \url[OLPC]{http://www.laptop.org}
26549 not encourage students to use illegal copies of educational software
26552 be immune to licensing/availability/price changes of the chosen tool chain
26555 be able to change to a new target platform without having to adopt a new
26559 have complete control over and insight into the tool chain
26562 make your students aware about the pros and cons of open source software
26566 give back to the public as you are probably at least partially publically
26570 give students a chance to publically prove their skills and to possibly
26571 see a world wide impact
26574 then SDCC is probably among the first choices.
26575 Well, probably SDCC might be the only choice.
26578 SDCC Technical Data
26582 \begin_inset LatexCommand \index{Optimizations}
26589 SDCC performs a host of standard optimizations in addition to some MCU specific
26594 Sub-expression Elimination
26595 \begin_inset LatexCommand \index{Subexpression elimination}
26602 The compiler does local and
26628 will be translated to
26640 Some subexpressions are not as obvious as the above example, e.g.:
26650 In this case the address arithmetic a->b[i] will be computed only once;
26651 the equivalent code in C would be.
26663 The compiler will try to keep these temporary variables in registers.
26666 Dead-Code Elimination
26667 \begin_inset LatexCommand \index{Dead-code elimination}
26688 i = 1; \SpecialChar ~
26697 global = 1;\SpecialChar ~
26710 global = 3;\SpecialChar ~
26735 \begin_inset LatexCommand \index{Copy propagation}
26791 Note: the dead stores created by this copy propagation will be eliminated
26792 by dead-code elimination.
26796 \begin_inset LatexCommand \index{Loop optimization}
26801 \begin_inset LatexCommand \label{sub:Loop-Optimizations}
26808 Two types of loop optimizations are done by SDCC
26816 of loop induction variables.
26817 In addition to the strength reduction the optimizer marks the induction
26818 variables and the register allocator tries to keep the induction variables
26819 in registers for the duration of the loop.
26820 Because of this preference of the register allocator
26821 \begin_inset LatexCommand \index{Register allocation}
26825 , loop induction optimization causes an increase in register pressure, which
26826 may cause unwanted spilling of other temporary variables into the stack
26827 \begin_inset LatexCommand \index{stack}
26832 The compiler will generate a warning message when it is forced to allocate
26833 extra space either on the stack or data space.
26834 If this extra space allocation is undesirable then induction optimization
26835 can be eliminated either for the entire source file (with -
26845 -noinduction option) or for a given function only using #pragma\SpecialChar ~
26847 \begin_inset LatexCommand \index{\#pragma noinduction}
26860 for (i = 0 ; i < 100 ; i ++)
26876 for (i = 0; i < 100; i++)
26885 As mentioned previously some loop invariants are not as apparent, all static
26886 address computations are also moved out of the loop.
26891 \begin_inset LatexCommand \index{Strength reduction}
26895 , this optimization substitutes an expression by a cheaper expression:
26900 for (i=0;i < 100; i++)
26918 for (i=0;i< 100;i++) {
26924 ar[itemp1] = itemp2;
26941 The more expensive multiplication
26942 \begin_inset LatexCommand \index{Multiplication}
26946 is changed to a less expensive addition.
26950 \begin_inset LatexCommand \index{Loop reversing}
26957 This optimization is done to reduce the overhead of checking loop boundaries
26958 for every iteration.
26959 Some simple loops can be reversed and implemented using a
26960 \begin_inset Quotes eld
26963 decrement and jump if not zero
26964 \begin_inset Quotes erd
26968 SDCC checks for the following criterion to determine if a loop is reversible
26969 (note: more sophisticated compilers use data-dependency analysis to make
26970 this determination, SDCC uses a more simple minded analysis).
26973 The 'for' loop is of the form
26979 for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
26989 The <for body> does not contain
26990 \begin_inset Quotes eld
26994 \begin_inset Quotes erd
26998 \begin_inset Quotes erd
27004 All goto's are contained within the loop.
27007 No function calls within the loop.
27010 The loop control variable <sym> is not assigned any value within the loop
27013 The loop control variable does NOT participate in any arithmetic operation
27017 There are NO switch statements in the loop.
27020 Algebraic Simplifications
27023 SDCC does numerous algebraic simplifications, the following is a small sub-set
27024 of these optimizations.
27029 i = j + 0;\SpecialChar ~
27033 /* changed to: */\SpecialChar ~
27039 i /= 2;\SpecialChar ~
27046 /* changed to: */\SpecialChar ~
27052 i = j - j;\SpecialChar ~
27056 /* changed to: */\SpecialChar ~
27062 i = j / 1;\SpecialChar ~
27066 /* changed to: */\SpecialChar ~
27073 Note the subexpressions
27074 \begin_inset LatexCommand \index{Subexpression}
27078 given above are generally introduced by macro expansions or as a result
27079 of copy/constant propagation.
27082 'switch' Statements
27083 \begin_inset LatexCommand \label{sub:'switch'-Statements}
27088 \begin_inset LatexCommand \index{switch statement}
27095 SDCC can optimize switch statements to jump tables
27096 \begin_inset LatexCommand \index{jump tables}
27101 It makes the decision based on an estimate of the generated code size.
27102 SDCC is quite liberal in the requirements for jump table generation:
27105 The labels need not be in order, and the starting number need not be one
27106 or zero, the case labels are in numerical sequence or not too many case
27107 labels are missing.
27113 switch(i) {\SpecialChar ~
27144 case 4: ...\SpecialChar ~
27176 case 5: ...\SpecialChar ~
27208 case 3: ...\SpecialChar ~
27239 case 6: ...\SpecialChar ~
27271 case 7: ...\SpecialChar ~
27303 case 8: ...\SpecialChar ~
27335 case 9: ...\SpecialChar ~
27367 case 10: ...\SpecialChar ~
27398 case 11: ...\SpecialChar ~
27465 Both the above switch statements will be implemented using a jump-table.
27466 The example to the right side is slightly more efficient as the check for
27467 the lower boundary of the jump-table is not needed.
27471 The number of case labels is not larger than supported by the target architectur
27475 If the case labels are not in numerical sequence ('gaps' between cases)
27476 SDCC checks whether a jump table with additionally inserted dummy cases
27477 is still attractive.
27481 If the starting number is not zero and a check for the lower boundary of
27482 the jump-table can thus be eliminated SDCC might insert dummy cases 0,
27487 Switch statements which have large gaps in the numeric sequence or those
27488 that have too many case labels can be split into more than one switch statement
27489 for efficient code generation, e.g.:
27569 If the above switch statement is broken down into two switch statements
27659 then both the switch statements will be implemented using jump-tables whereas
27660 the unmodified switch statement will not be.
27663 There might be reasons which SDCC cannot know about to either favour or
27664 not favour jump tables.
27665 If the target system has to be as quick for the last switch case as for
27666 the first (pro jump table), or if the switch argument is known to be zero
27667 in the majority of the cases (contra jump table).
27670 The pragma nojtbound
27671 \begin_inset LatexCommand \index{\#pragma nojtbound}
27675 can be used to turn off checking the
27688 It has no effect if a default label is supplied.
27689 Use of this pragma is dangerous: if the switch
27690 \begin_inset LatexCommand \index{switch statement}
27694 argument is not matched by a case statement the processor will happily
27698 Bit-shifting Operations
27699 \begin_inset LatexCommand \index{Bit shifting}
27706 Bit shifting is one of the most frequently used operation in embedded programmin
27708 SDCC tries to implement bit-shift operations in the most efficient way
27724 generates the following code:
27741 In general SDCC will never setup a loop if the shift count is known.
27784 \begin_inset LatexCommand \index{Bit rotation}
27791 A special case of the bit-shift operation is bit rotation
27792 \begin_inset LatexCommand \index{rotating bits}
27796 , SDCC recognizes the following expression to be a left bit-rotation:
27806 char i;\SpecialChar ~
27817 /* unsigned is needed for rotation */
27822 i = ((i << 1) | (i >> 7));
27831 will generate the following code:
27850 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
27851 ns of this case will also be recognized as bit-rotation, i.e.:
27856 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
27859 Nibble and Byte Swapping
27862 Other special cases of the bit-shift operations are nibble or byte swapping
27863 \begin_inset LatexCommand \index{swapping nibbles/bytes}
27867 , SDCC recognizes the following expressions:
27890 i = ((i << 4) | (i >> 4));
27896 j = ((j << 8) | (j >> 8));
27899 and generates a swap instruction for the nibble swapping
27900 \begin_inset LatexCommand \index{Nibble swapping}
27904 or move instructions for the byte swapping
27905 \begin_inset LatexCommand \index{Byte swapping}
27911 \begin_inset Quotes sld
27915 \begin_inset Quotes srd
27918 example can be used to convert from little to big-endian or vice versa.
27919 If you want to change the endianness of a
27923 integer you have to cast to
27930 Note that SDCC stores numbers in little-endian
27936 Usually 8-bit processors don't care much about endianness.
27937 This is not the case for the standard 8051 which only has an instruction
27943 \begin_inset LatexCommand \index{DPTR}
27951 so little-endian is the more efficient byte order.
27955 \begin_inset LatexCommand \index{little-endian}
27960 \begin_inset LatexCommand \index{Endianness}
27965 lowest order first).
27969 \begin_inset LatexCommand \index{Highest Order Bit}
27974 \begin_inset LatexCommand \index{Any Order Bit}
27981 It is frequently required to obtain the highest order bit of an integral
27982 type (long, int, short or char types).
27983 Also obtaining any other order bit is not uncommon.
27984 SDCC recognizes the following expressions to yield the highest order bit
27985 and generates optimized code for it, e.g.:
27998 unsigned char hob1, aob1;
28002 bit hob2, hob3, aob2, aob3;
28011 hob1 = (gint >> 15) & 1;
28015 hob2 = (gint >> 15) & 1;
28019 hob3 = gint & 0x8000;
28023 aob1 = (gint >> 9) & 1;
28027 aob2 = (gint >> 8) & 1;
28031 aob3 = gint & 0x0800;
28041 will generate the following code:
28074 000A E5*01\SpecialChar ~
28101 000C 23\SpecialChar ~
28132 000D 54 01\SpecialChar ~
28159 000F F5*02\SpecialChar ~
28214 0011 E5*01\SpecialChar ~
28241 0013 33\SpecialChar ~
28271 0014 92*00\SpecialChar ~
28326 0016 E5*01\SpecialChar ~
28353 0018 33\SpecialChar ~
28383 0019 92*01\SpecialChar ~
28438 001B E5*01\SpecialChar ~
28465 001D 03\SpecialChar ~
28496 001E 54 01\SpecialChar ~
28523 0020 F5*03\SpecialChar ~
28578 0022 E5*01\SpecialChar ~
28605 0024 13\SpecialChar ~
28635 0025 92*02\SpecialChar ~
28690 0027 E5*01\SpecialChar ~
28717 0029 A2 E3\SpecialChar ~
28744 002B 92*03\SpecialChar ~
28772 Other variations of these cases however will
28777 They are standard C expressions, so I heartily recommend these be the only
28778 way to get the highest order bit, (it is portable).
28779 Of course it will be recognized even if it is embedded in other expressions,
28785 xyz = gint + ((gint >> 15) & 1);
28788 will still be recognized.
28792 \begin_inset LatexCommand \index{Higher Order Byte}
28796 / Higher Order Word
28797 \begin_inset LatexCommand \index{Higher Order Word}
28804 It is also frequently required to obtain a higher order byte or word of
28805 a larger integral type (long, int or short types).
28806 SDCC recognizes the following expressions to yield the higher order byte
28807 or word and generates optimized code for it, e.g.:
28814 unsigned long int glong;
28822 unsigned char hob1, hob2;
28826 unsigned int how1, how2;
28835 hob1 = (gint >> 8) & 0xFF;
28839 hob2 = glong >> 24;
28843 how1 = (glong >> 16) & 0xFFFF;
28857 will generate the following code:
28890 0037 85*01*06\SpecialChar ~
28912 _foo_hob1_1_1,(_gint + 1)
28942 003A 85*05*07\SpecialChar ~
28964 _foo_hob2_1_1,(_glong + 3)
28994 003D 85*04*08\SpecialChar ~
29016 _foo_how1_1_1,(_glong + 2)
29018 0040 85*05*09\SpecialChar ~
29040 (_foo_how1_1_1 + 1),(_glong + 3)
29042 0043 85*03*0A\SpecialChar ~
29064 _foo_how2_1_1,(_glong + 1)
29066 0046 85*04*0B\SpecialChar ~
29088 (_foo_how2_1_1 + 1),(_glong + 2)
29091 Again, variations of these cases may
29096 They are standard C expressions, so I heartily recommend these be the only
29097 way to get the higher order byte/word, (it is portable).
29098 Of course it will be recognized even if it is embedded in other expressions,
29104 xyz = gint + ((gint >> 8) & 0xFF);
29107 will still be recognized.
29111 \begin_inset LatexCommand \label{sub:Peephole-Optimizer}
29116 \begin_inset LatexCommand \index{Peephole optimizer}
29123 The compiler uses a rule based, pattern matching and re-writing mechanism
29124 for peep-hole optimization.
29129 a peep-hole optimizer by Christopher W.
29130 Fraser (cwfraser\SpecialChar ~
29133 A default set of rules are compiled into the compiler, additional rules
29134 may be added with the
29147 \begin_inset LatexCommand \index{-\/-peep-file}
29154 The rule language is best illustrated with examples.
29178 The above rule will change the following assembly
29179 \begin_inset LatexCommand \index{Assembler routines}
29201 Note: All occurrences of a
29205 (pattern variable) must denote the same string.
29206 With the above rule, the assembly sequence:
29216 will remain unmodified.
29220 Other special case optimizations may be added by the user (via
29236 some variants of the 8051 MCU
29237 \begin_inset LatexCommand \index{MCS51 variants}
29250 The following two rules will change all
29269 replace { lcall %1 } by { acall %1 }
29271 replace { ljmp %1 } by { ajmp %1 }
29276 inline-assembler code
29278 is also passed through the peep hole optimizer, thus the peephole optimizer
29279 can also be used as an assembly level macro expander.
29280 The rules themselves are MCU dependent whereas the rule language infra-structur
29281 e is MCU independent.
29282 Peephole optimization rules for other MCU can be easily programmed using
29287 The syntax for a rule is as follows:
29292 rule := replace [ restart ] '{' <assembly sequence> '
29330 <assembly sequence> '
29348 '}' [if <functionName> ] '
29353 <assembly sequence> := assembly instruction (each instruction including
29354 labels must be on a separate line).
29358 The optimizer will apply to the rules one by one from the top in the sequence
29359 of their appearance, it will terminate when all rules are exhausted.
29360 If the 'restart' option is specified, then the optimizer will start matching
29361 the rules again from the top, this option for a rule is expensive (performance)
29362 , it is intended to be used in situations where a transformation will trigger
29363 the same rule again.
29364 An example of this (not a good one, it has side effects) is the following
29387 Note that the replace pattern cannot be a blank, but can be a comment line.
29388 Without the 'restart' option only the innermost 'pop' 'push' pair would
29389 be eliminated, i.e.:
29419 the restart option the rule will be applied again to the resulting code
29420 and then all the pop-push pairs will be eliminated to yield:
29430 A conditional function can be attached to a rule.
29431 Attaching rules are somewhat more involved, let me illustrate this with
29458 The optimizer does a look-up of a function name table defined in function
29463 in the source file SDCCpeeph.c, with the name
29468 If it finds a corresponding entry the function is called.
29469 Note there can be no parameters specified for these functions, in this
29474 is crucial, since the function
29478 expects to find the label in that particular variable (the hash table containin
29479 g the variable bindings is passed as a parameter).
29480 If you want to code more such functions, take a close look at the function
29481 labelInRange and the calling mechanism in source file SDCCpeeph.c.
29482 Currently implemented are
29484 labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
29485 24bitMode, portIsDS390, 24bitModeAndPortDS390
29494 I know this whole thing is a little kludgey, but maybe some day we will
29495 have some better means.
29496 If you are looking at this file, you will see the default rules that are
29497 compiled into the compiler, you can add your own rules in the default set
29498 there if you get tired of specifying the -
29512 \begin_inset LatexCommand \index{ANSI-compliance}
29517 \begin_inset LatexCommand \label{sub:ANSI-Compliance}
29524 The latest publically available version of the standard
29526 ISO/IEC 9899 - Programming languages - C
29528 should be available at:
29529 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
29538 Deviations from the compliance:
29541 functions are not reentrant
29542 \begin_inset LatexCommand \index{reentrant}
29546 unless explicitly declared as such or the
29559 \begin_inset LatexCommand \index{-\/-stack-auto}
29565 command line option is specified.
29569 \begin_inset LatexCommand \index{struct}
29574 \begin_inset LatexCommand \index{union}
29578 cannot be assigned values directly, cannot be passed as function parameters
29579 or assigned to each other and cannot be a return value
29580 \begin_inset LatexCommand \index{return value}
29584 from a function, e.g.:
29610 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
29629 s parms) /* invalid in SDCC although allowed in ANSI */
29650 return rets; /* is invalid in SDCC although allowed in ANSI */
29656 initialization of structure arrays must be fully braced.
29662 struct s { char x } a[] = {1, 2};\SpecialChar ~
29667 /* invalid in SDCC */
29669 struct s { char x } a[] = {{1}, {2}}; /* OK */
29674 \begin_inset LatexCommand \index{long long (not supported)}
29679 \begin_inset LatexCommand \index{int (64 bit) (not supported)}
29687 \begin_inset LatexCommand \index{double (not supported)}
29691 ' precision floating point
29692 \begin_inset LatexCommand \index{Floating point support}
29700 \begin_inset LatexCommand \index{K\&R style}
29704 function declarations are NOT allowed.
29710 foo(i,j) /* this old style of function declarations */
29712 int i,j; /* are valid in ANSI but not valid in SDCC */
29727 Most enhancements in C99 are not supported, f.e.:
29735 \begin_inset LatexCommand \index{inline (not supported)}
29741 int increment (int a) { return a+1; } /* is invalid in SDCC although allowed
29747 can be used as a work around */
29755 i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
29759 Certain words that are valid identifiers in the standard may be reserved
29760 words in SDCC unless the
29773 \begin_inset LatexCommand \index{-\/-std-c89}
29788 \begin_inset LatexCommand \index{-\/-std-c99}
29794 command line options are used.
29795 These may include (depending on the selected processor): 'at', 'banked',
29796 'bit', 'code', 'critical', 'data', 'eeprom', 'far', 'flash', 'idata', 'interrup
29797 t', 'near', 'nonbanked', 'pdata', 'reentrant', 'sbit', 'sfr', 'shadowregs',
29798 'sram', 'using', 'wparam', 'xdata', '_overlay', '_asm', '_endasm', and
29800 Compliant equivalents of these keywords are always available in a form
29801 that begin with two underscores
29802 \begin_inset LatexCommand \index{\_\_ (prefix for extended keywords)}
29807 '__data' instead of 'data'.
29810 Cyclomatic Complexity
29811 \begin_inset LatexCommand \index{Cyclomatic complexity}
29818 Cyclomatic complexity of a function is defined as the number of independent
29819 paths the program can take during execution of the function.
29820 This is an important number since it defines the number test cases you
29821 have to generate to validate the function.
29822 The accepted industry standard for complexity number is 10, if the cyclomatic
29823 complexity reported by SDCC exceeds 10 you should think about simplification
29824 of the function logic.
29825 Note that the complexity level is not related to the number of lines of
29826 code in a function.
29827 Large functions can have low complexity, and small functions can have large
29833 SDCC uses the following formula to compute the complexity:
29838 complexity = (number of edges in control flow graph) - (number of nodes
29839 in control flow graph) + 2;
29843 Having said that the industry standard is 10, you should be aware that in
29844 some cases it be may unavoidable to have a complexity level of less than
29846 For example if you have switch statement with more than 10 case labels,
29847 each case label adds one to the complexity level.
29848 The complexity level is by no means an absolute measure of the algorithmic
29849 complexity of the function, it does however provide a good starting point
29850 for which functions you might look at for further optimization.
29853 Retargetting for other Processors
29856 The issues for retargetting the compiler are far too numerous to be covered
29858 What follows is a brief description of each of the seven phases of the
29859 compiler and its MCU dependency.
29862 Parsing the source and building the annotated parse tree.
29863 This phase is largely MCU independent (except for the language extensions).
29864 Syntax & semantic checks are also done in this phase, along with some initial
29865 optimizations like back patching labels and the pattern matching optimizations
29866 like bit-rotation etc.
29869 The second phase involves generating an intermediate code which can be easy
29870 manipulated during the later phases.
29871 This phase is entirely MCU independent.
29872 The intermediate code generation assumes the target machine has unlimited
29873 number of registers, and designates them with the name iTemp.
29874 The compiler can be made to dump a human readable form of the code generated
29888 This phase does the bulk of the standard optimizations and is also MCU independe
29890 This phase can be broken down into several sub-phases:
29894 Break down intermediate code (iCode) into basic blocks.
29896 Do control flow & data flow analysis on the basic blocks.
29898 Do local common subexpression elimination, then global subexpression elimination
29900 Dead code elimination
29904 If loop optimizations caused any changes then do 'global subexpression eliminati
29905 on' and 'dead code elimination' again.
29908 This phase determines the live-ranges; by live range I mean those iTemp
29909 variables defined by the compiler that still survive after all the optimization
29911 Live range analysis
29912 \begin_inset LatexCommand \index{Live range analysis}
29916 is essential for register allocation, since these computation determines
29917 which of these iTemps will be assigned to registers, and for how long.
29920 Phase five is register allocation.
29921 There are two parts to this process.
29925 The first part I call 'register packing' (for lack of a better term).
29926 In this case several MCU specific expression folding is done to reduce
29931 The second part is more MCU independent and deals with allocating registers
29932 to the remaining live ranges.
29933 A lot of MCU specific code does creep into this phase because of the limited
29934 number of index registers available in the 8051.
29937 The Code generation phase is (unhappily), entirely MCU dependent and very
29938 little (if any at all) of this code can be reused for other MCU.
29939 However the scheme for allocating a homogenized assembler operand for each
29940 iCode operand may be reused.
29943 As mentioned in the optimization section the peep-hole optimizer is rule
29944 based system, which can reprogrammed for other MCUs.
29947 More information is available in a wiki
29948 \begin_inset LatexCommand \index{wiki}
29953 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/release_wiki/index.php?page=SDCC+internals+and+porting}
29957 ) and in the thread
29958 \begin_inset LatexCommand \url{http://sf.net/mailarchive/message.php?msg_id=13954144}
29966 \begin_inset LatexCommand \index{Compiler internals}
29973 The anatomy of the compiler
29974 \begin_inset LatexCommand \label{sub:The-anatomy-of}
29983 This is an excerpt from an article published in Circuit Cellar Magazine
29989 It's a little outdated (the compiler is much more efficient now and user/develo
29990 per friendly), but pretty well exposes the guts of it all.
29996 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
29997 It is fairly easy to retarget for other 8-bit MCU.
29998 Here we take a look at some of the internals of the compiler.
30003 \begin_inset LatexCommand \index{Parsing}
30010 Parsing the input source file and creating an AST (Annotated Syntax Tree
30011 \begin_inset LatexCommand \index{Annotated syntax tree}
30016 This phase also involves propagating types (annotating each node of the
30017 parse tree with type information) and semantic analysis.
30018 There are some MCU specific parsing rules.
30019 For example the storage classes, the extended storage classes are MCU specific
30020 while there may be a xdata storage class for 8051 there is no such storage
30021 class for z80 or Atmel AVR.
30022 SDCC allows MCU specific storage class extensions, i.e.
30023 xdata will be treated as a storage class specifier when parsing 8051 C
30024 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
30029 \begin_inset LatexCommand \index{iCode}
30036 Intermediate code generation.
30037 In this phase the AST is broken down into three-operand form (iCode).
30038 These three operand forms are represented as doubly linked lists.
30039 ICode is the term given to the intermediate form generated by the compiler.
30040 ICode example section shows some examples of iCode generated for some simple
30041 C source functions.
30045 \begin_inset LatexCommand \index{Optimizations}
30052 Bulk of the target independent optimizations is performed in this phase.
30053 The optimizations include constant propagation, common sub-expression eliminati
30054 on, loop invariant code movement, strength reduction of loop induction variables
30055 and dead-code elimination.
30058 Live range analysis
30059 \begin_inset LatexCommand \index{Live range analysis}
30066 During intermediate code generation phase, the compiler assumes the target
30067 machine has infinite number of registers and generates a lot of temporary
30069 The live range computation determines the lifetime of each of these compiler-ge
30070 nerated temporaries.
30071 A picture speaks a thousand words.
30072 ICode example sections show the live range annotations for each of the
30074 It is important to note here, each iCode is assigned a number in the order
30075 of its execution in the function.
30076 The live ranges are computed in terms of these numbers.
30077 The from number is the number of the iCode which first defines the operand
30078 and the to number signifies the iCode which uses this operand last.
30081 Register Allocation
30082 \begin_inset LatexCommand \index{Register allocation}
30089 The register allocation determines the type and number of registers needed
30091 In most MCUs only a few registers can be used for indirect addressing.
30092 In case of 8051 for example the registers R0 & R1 can be used to indirectly
30093 address the internal ram and DPTR to indirectly address the external ram.
30094 The compiler will try to allocate the appropriate register to pointer variables
30096 ICode example section shows the operands annotated with the registers assigned
30098 The compiler will try to keep operands in registers as much as possible;
30099 there are several schemes the compiler uses to do achieve this.
30100 When the compiler runs out of registers the compiler will check to see
30101 if there are any live operands which is not used or defined in the current
30102 basic block being processed, if there are any found then it will push that
30103 operand and use the registers in this block, the operand will then be popped
30104 at the end of the basic block.
30108 There are other MCU specific considerations in this phase.
30109 Some MCUs have an accumulator; very short-lived operands could be assigned
30110 to the accumulator instead of a general-purpose register.
30116 Figure II gives a table of iCode
30117 \begin_inset LatexCommand \index{iCode}
30121 operations supported by the compiler.
30122 The code generation involves translating these operations into corresponding
30123 assembly code for the processor.
30124 This sounds overly simple but that is the essence of code generation.
30125 Some of the iCode operations are generated on a MCU specific manner for
30126 example, the z80 port does not use registers to pass parameters so the
30127 SEND and RECV iCode operations will not be generated, and it also does
30128 not support JUMPTABLES.
30137 \begin_inset Tabular
30138 <lyxtabular version="3" rows="39" columns="4">
30139 <features islongtable="true" headBottomDL="true">
30140 <column alignment="block" valignment="top" leftline="true" width="13col%">
30141 <column alignment="left" valignment="top" leftline="true" width="13col%">
30142 <column alignment="block" valignment="top" leftline="true" width="22col%">
30143 <column alignment="block" valignment="top" leftline="true" rightline="true" width="40col%">
30144 <row topline="true" bottomline="true" endhead="true">
30145 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30155 \begin_inset LatexCommand \index{iCode}
30162 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30172 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30182 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30193 <row topline="true">
30194 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30204 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30211 IC_LEFT() IC_RESULT()
30214 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30224 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30231 IC_RESULT = ! IC_LEFT;
30235 <row topline="true">
30236 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30246 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30253 IC_LEFT() IC_RESULT()
30256 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30263 Bitwise complement of
30266 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30273 IC_RESULT = ~IC_LEFT;
30277 <row topline="true">
30278 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30288 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30295 IC_LEFT() IC_RESULT()
30298 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30305 Rotate right with carry
30308 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30315 IC_RESULT = (IC_LEFT << 1) | (IC_LEFT >> (sizeof(IC_LEFT)*8-1));
30319 <row topline="true">
30320 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30330 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30337 IC_LEFT() IC_RESULT()
30340 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30347 Rotate left with carry
30350 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30357 IC_RESULT = (IC_LEFT << (sizeof(LC_LEFT)*8-1) ) | (IC_LEFT >> 1);
30361 <row topline="true">
30362 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30372 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30379 IC_LEFT() IC_RESULT()
30382 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30389 Get the highest order bit of IC_LEFT
30392 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30399 IC_RESULT = (IC_LEFT >> (sizeof(IC_LEFT)*8 -1));
30403 <row topline="true">
30404 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30414 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30421 IC_LEFT() IC_RESULT()
30424 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30434 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30441 IC_RESULT = - IC_LEFT;
30445 <row topline="true">
30446 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30456 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30466 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30473 Push the operand into stack
30476 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30487 <row topline="true">
30488 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30498 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30508 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30515 Pop the operand from the stack
30518 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30529 <row topline="true">
30530 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30540 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30547 IC_LEFT() IC_RESULT()
30550 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30557 Call the function represented by IC_LEFT
30560 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30567 IC_RESULT = IC_LEFT();
30571 <row topline="true">
30572 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30582 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30589 IC_LEFT() IC_RESULT()
30592 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30599 Call via function pointer
30602 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30609 IC_RESULT = (*IC_LEFT)();
30613 <row topline="true">
30614 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30624 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30634 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30641 Return the value in operand IC_LEFT
30644 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30655 <row topline="true">
30656 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30666 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30676 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30686 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30697 <row topline="true">
30698 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30708 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30718 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30728 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30739 <row topline="true">
30740 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30750 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30757 IC_LEFT() IC_RIGHT() IC_RESULT()
30760 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30770 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30777 IC_RESULT = IC_LEFT + IC_RIGHT
30781 <row topline="true">
30782 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30792 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30799 IC_LEFT() IC_RIGHT() IC_RESULT()
30802 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30812 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30819 IC_RESULT = IC_LEFT - IC_RIGHT
30823 <row topline="true">
30824 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30834 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30841 IC_LEFT() IC_RIGHT() IC_RESULT()
30844 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30854 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30861 IC_RESULT = IC_LEFT * IC_RIGHT;
30865 <row topline="true">
30866 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30876 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30883 IC_LEFT() IC_RIGHT() IC_RESULT()
30886 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30896 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30903 IC_RESULT = IC_LEFT / IC_RIGHT;
30907 <row topline="true">
30908 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30918 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30925 IC_LEFT() IC_RIGHT() IC_RESULT()
30928 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30938 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30945 IC_RESULT = IC_LEFT % IC_RIGHT;
30949 <row topline="true">
30950 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30960 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30967 IC_LEFT() IC_RIGHT() IC_RESULT()
30970 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30980 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30987 IC_RESULT = IC_LEFT < IC_RIGHT;
30991 <row topline="true">
30992 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31002 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31009 IC_LEFT() IC_RIGHT() IC_RESULT()
31012 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31022 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31029 IC_RESULT = IC_LEFT > IC_RIGHT;
31033 <row topline="true">
31034 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31044 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31051 IC_LEFT() IC_RIGHT() IC_RESULT()
31054 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31064 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31071 IC_RESULT = IC_LEFT == IC_RIGHT;
31075 <row topline="true">
31076 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31086 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31093 IC_LEFT() IC_RIGHT() IC_RESULT()
31096 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31103 Logical and operation
31106 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31113 IC_RESULT = IC_LEFT && IC_RIGHT;
31117 <row topline="true">
31118 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31128 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31135 IC_LEFT() IC_RIGHT() IC_RESULT()
31138 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31145 Logical or operation
31148 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31155 IC_RESULT = IC_LEFT || IC_RIGHT;
31159 <row topline="true">
31160 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31170 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31177 IC_LEFT() IC_RIGHT() IC_RESULT()
31180 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31190 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31197 IC_RESULT = IC_LEFT ^ IC_RIGHT;
31201 <row topline="true">
31202 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31212 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31219 IC_LEFT() IC_RIGHT() IC_RESULT()
31222 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31232 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31239 IC_RESULT = IC_LEFT | IC_RIGHT;
31243 <row topline="true">
31244 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31254 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31261 IC_LEFT() IC_RIGHT() IC_RESULT()
31264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31274 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31281 IC_RESULT = IC_LEFT & IC_RIGHT;
31285 <row topline="true">
31286 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31296 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31303 IC_LEFT() IC_RIGHT() IC_RESULT()
31306 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31316 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31323 IC_RESULT = IC_LEFT << IC_RIGHT
31327 <row topline="true">
31328 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31338 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31345 IC_LEFT() IC_RIGHT() IC_RESULT()
31348 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31358 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31365 IC_RESULT = IC_LEFT >> IC_RIGHT
31369 <row topline="true">
31370 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31382 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31389 IC_LEFT() IC_RESULT()
31392 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31402 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31409 IC_RESULT = (*IC_LEFT);
31413 <row topline="true">
31414 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31424 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31431 IC_RIGHT() IC_RESULT()
31434 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31444 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31451 (*IC_RESULT) = IC_RIGHT;
31455 <row topline="true">
31456 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31466 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31473 IC_RIGHT() IC_RESULT()
31476 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31486 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31493 IC_RESULT = IC_RIGHT;
31497 <row topline="true">
31498 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31508 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31515 IC_COND IC_TRUE IC_LABEL
31518 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31526 If true label is present then jump to true label if condition is true else
31527 jump to false label if condition is false
31530 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31537 if (IC_COND) goto IC_TRUE;
31543 If (!IC_COND) goto IC_FALSE;
31547 <row topline="true">
31548 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31558 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31565 IC_LEFT() IC_RESULT()
31568 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31578 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31585 IC_RESULT = &IC_LEFT();
31589 <row topline="true">
31590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31600 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31607 IC_JTCOND IC_JTLABELS
31610 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31617 Jump to list of labels depending on the value of JTCOND
31620 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31631 <row topline="true">
31632 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31642 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31649 IC_RIGHT() IC_LEFT() IC_RESULT()
31652 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31662 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31669 IC_RESULT = (typeof IC_LEFT) IC_RIGHT;
31673 <row topline="true">
31674 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31684 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31694 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31701 This is used for passing parameters in registers;
31703 move IC_LEFT to the next available parameter register.
31706 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31717 <row topline="true">
31718 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31728 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31738 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31745 This is used for receiving parameters passed in registers;
31747 Move the values in the next parameter register to IC_RESULT
31750 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31761 <row topline="true" bottomline="true">
31762 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31770 (some more have been added)
31773 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31780 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31787 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31813 In the original article Figure II was announced to be downloadable on
31818 ftp://ftp.circuitcellar.com/pub/Circuit_Cellar/2000/121/dutta.ZIP
31822 \begin_inset LatexCommand \index{iCode}
31829 This section shows some details of iCode.
31830 The example C code does not do anything useful; it is used as an example
31831 to illustrate the intermediate code generated by the compiler.
31843 /* This function does nothing useful.
31850 for the purpose of explaining iCode */
31853 short function (data int *x)
31861 short i=10; \SpecialChar ~
31863 /* dead initialization eliminated */
31868 short sum=10; /* dead initialization eliminated */
31881 while (*x) *x++ = *p++;
31895 /* compiler detects i,j to be induction variables */
31899 for (i = 0, j = 10 ; i < 10 ; i++, j
31925 mul += i * 3; \SpecialChar ~
31927 /* this multiplication remains */
31933 gint += j * 3;\SpecialChar ~
31935 /* this multiplication changed to addition */
31949 In addition to the operands each iCode contains information about the filename
31950 and line it corresponds to in the source file.
31951 The first field in the listing should be interpreted as follows:
31956 Filename(linenumber: iCode Execution sequence number : ICode hash table
31957 key : loop depth of the iCode).
31962 Then follows the human readable form of the ICode operation.
31963 Each operand of this triplet form can be of three basic types a) compiler
31964 generated temporary b) user defined variable c) a constant value.
31965 Note that local variables and parameters are replaced by compiler generated
31968 \begin_inset LatexCommand \index{Live range analysis}
31972 are computed only for temporaries (i.e.
31973 live ranges are not computed for global variables).
31975 \begin_inset LatexCommand \index{Register allocation}
31979 are allocated for temporaries only.
31980 Operands are formatted in the following manner:
31985 Operand Name [lr live-from : live-to ] { type information } [ registers
31991 As mentioned earlier the live ranges are computed in terms of the execution
31992 sequence number of the iCodes, for example
31994 the iTemp0 is live from (i.e.
31995 first defined in iCode with execution sequence number 3, and is last used
31996 in the iCode with sequence number 5).
31997 For induction variables such as iTemp21 the live range computation extends
31998 the lifetime from the start to the end of the loop.
32000 The register allocator used the live range information to allocate registers,
32001 the same registers may be used for different temporaries if their live
32002 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
32003 iTemp17 since their live ranges do not overlap.
32004 In addition the allocator also takes into consideration the type and usage
32005 of a temporary, for example itemp6 is a pointer to near space and is used
32006 as to fetch data from (i.e.
32007 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
32008 Some short lived temporaries are allocated to special registers which have
32009 meaning to the code generator e.g.
32010 iTemp13 is allocated to a pseudo register CC which tells the back end that
32011 the temporary is used only for a conditional jump the code generation makes
32012 use of this information to optimize a compare and jump ICode.
32014 There are several loop optimizations
32015 \begin_inset LatexCommand \index{Loop optimization}
32019 performed by the compiler.
32020 It can detect induction variables iTemp21(i) and iTemp23(j).
32021 Also note the compiler does selective strength reduction
32022 \begin_inset LatexCommand \index{Strength reduction}
32027 the multiplication of an induction variable in line 18 (gint = j * 3) is
32028 changed to addition, a new temporary iTemp17 is allocated and assigned
32029 a initial value, a constant 3 is then added for each iteration of the loop.
32030 The compiler does not change the multiplication
32031 \begin_inset LatexCommand \index{Multiplication}
32035 in line 17 however since the processor does support an 8 * 8 bit multiplication.
32037 Note the dead code elimination
32038 \begin_inset LatexCommand \index{Dead-code elimination}
32042 optimization eliminated the dead assignments in line 7 & 8 to I and sum
32050 Sample.c (5:1:0:0) _entry($9) :
32055 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
32060 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
32065 Sample.c(11:4:53:0) preHeaderLbl0($11) :
32070 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
32076 Sample.c(11:6:5:1) _whilecontinue_0($1) :
32081 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
32087 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
32092 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
32098 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
32104 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
32110 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
32116 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
32117 * int}[r0] + 0x2 {short}
32122 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
32127 Sample.c(11:17:21:0)_whilebreak_0($3) :
32132 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
32137 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
32142 Sample.c(15:20:54:0)preHeaderLbl1($13) :
32147 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
32152 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
32157 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
32162 Sample.c(15:24:26:1)_forcond_0($4) :
32167 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
32173 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
32178 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
32179 + ITemp21 [lr21:38]{short}[r4]
32184 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
32190 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
32191 + iTemp15 [lr29:30]{short}[r1]
32196 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
32202 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
32208 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
32214 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
32220 Sample.c(19:38:47:1) goto _forcond_0($4)
32225 Sample.c(19:39:48:0)_forbreak_0($7) :
32230 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
32231 + ITemp11 [lr19:40]{short}[r3]
32236 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
32241 Sample.c(20:42:51:0)_return($8) :
32246 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
32252 Finally the code generated for this function:
32293 ; ----------------------------------------------
32298 ; function function
32303 ; ----------------------------------------------
32313 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
32325 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
32337 ;_whilecontinue_0($1) :
32347 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
32352 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
32411 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
32430 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
32477 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
32517 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
32543 ; iTemp6 [lr5:16]{_near * int}[r0] =
32548 ; iTemp6 [lr5:16]{_near * int}[r0] +
32565 ; goto _whilecontinue_0($1)
32577 ; _whilebreak_0($3) :
32587 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
32599 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
32611 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
32623 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
32642 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
32671 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
32676 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
32721 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
32726 ; iTemp21 [lr21:38]{short}[r4]
32752 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
32785 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
32790 ; iTemp15 [lr29:30]{short}[r1]
32809 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
32856 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
32903 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
32915 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
32929 cjne r5,#0xff,00104$
32941 ; goto _forcond_0($4)
32953 ; _forbreak_0($7) :
32963 ; ret iTemp24 [lr40:41]{short}
33006 A few words about basic block successors, predecessors and dominators
33009 Successors are basic blocks
33010 \begin_inset LatexCommand \index{Basic blocks}
33014 that might execute after this basic block.
33016 Predecessors are basic blocks that might execute before reaching this basic
33019 Dominators are basic blocks that WILL execute before reaching this basic
33053 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
33056 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
33059 c) domVect of [BB4] = BB1 ...
33060 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
33068 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
33078 Thanks to all the other volunteer developers who have helped with coding,
33079 testing, web-page creation, distribution sets, etc.
33080 You know who you are :-)
33088 Also thanks to Sourceforge
33089 \begin_inset LatexCommand \url{http://www.sf.net}
33093 which has hosted the project since 1999 and donates significant download
33094 bandwidth and probably more than
33102 CPU cycles per day.
33110 more than 10^13 is an estimate: on my Athlon 2800+ it takes about (0.5+6.5+20)
33111 minutes for (configure+make+regression test), and there is (i386, amd64,
33112 alpha, ppc64, (mingw32), sparc, macosx).
33119 This document was initially written by Sandeep Dutta
33122 All product names mentioned herein may be trademarks
33123 \begin_inset LatexCommand \index{Trademarks}
33127 of their respective companies.
33134 To avoid confusion, the installation and building options for SDCC itself
33135 (chapter 2) are not part of the index.
33139 \begin_inset LatexCommand \printindex{}