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 \labelwidthstring 00.00.0000
8790 -fdollars-in-identifiers
8791 \begin_inset LatexCommand \index{-\/-fdollars-in-identifiers}
8797 Permit '$' as an identifier character
8799 \added_space_bottom bigskip \labelwidthstring 00.00.0000
8811 a SDCC compiler option but if you want
8815 warnings you can use a separate tool dedicated to syntax checking like
8817 \begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
8822 \begin_inset LatexCommand \index{lint (syntax checking tool)}
8827 \begin_inset LatexCommand \url{http://www.splint.org}
8832 To make your source files parseable by splint you will have to include
8838 \begin_inset LatexCommand \index{splint (syntax checking tool)}
8842 in your source file and add brackets around extended keywords (like
8845 \begin_inset Quotes sld
8858 \begin_inset Quotes srd
8866 \begin_inset Quotes sld
8869 __interrupt\SpecialChar ~
8871 \begin_inset Quotes srd
8879 Splint has an excellent on line manual at
8880 \begin_inset LatexCommand \url{http://www.splint.org/manual/}
8884 and it's capabilities go beyond pure syntax checking.
8885 You'll need to tell splint the location of SDCC's include files so a typical
8886 command line could look like this:
8890 splint\SpecialChar ~
8892 /usr/local/share/sdcc/include/mcs51/\SpecialChar ~
8897 Intermediate Dump Options
8898 \begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
8903 \begin_inset LatexCommand \index{Options intermediate dump}
8908 \begin_inset LatexCommand \index{Intermediate dump options}
8915 The following options are provided for the purpose of retargetting and debugging
8917 They provide a means to dump the intermediate code (iCode
8918 \begin_inset LatexCommand \index{iCode}
8922 ) generated by the compiler in human readable form at various stages of
8923 the compilation process.
8924 More on iCodes see chapter
8925 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
8930 \begin_inset Quotes srd
8933 The anatomy of the compiler
8934 \begin_inset Quotes srd
8939 \labelwidthstring 00.00.0000
8954 \begin_inset LatexCommand \index{-\/-dumpraw}
8960 This option will cause the compiler to dump the intermediate code into
8963 <source filename>.dumpraw
8965 just after the intermediate code has been generated for a function, i.e.
8966 before any optimizations are done.
8968 \begin_inset LatexCommand \index{Basic blocks}
8972 at this stage ordered in the depth first number, so they may not be in
8973 sequence of execution.
8975 \labelwidthstring 00.00.0000
8990 \begin_inset LatexCommand \index{-\/-dumpgcse}
8996 Will create a dump of iCode's, after global subexpression elimination
8997 \begin_inset LatexCommand \index{Global subexpression elimination}
9003 <source filename>.dumpgcse.
9005 \labelwidthstring 00.00.0000
9020 \begin_inset LatexCommand \index{-\/-dumpdeadcode}
9026 Will create a dump of iCode's, after deadcode elimination
9027 \begin_inset LatexCommand \index{Dead-code elimination}
9033 <source filename>.dumpdeadcode.
9035 \labelwidthstring 00.00.0000
9050 \begin_inset LatexCommand \index{-\/-dumploop}
9059 Will create a dump of iCode's, after loop optimizations
9060 \begin_inset LatexCommand \index{Loop optimization}
9066 <source filename>.dumploop.
9068 \labelwidthstring 00.00.0000
9083 \begin_inset LatexCommand \index{-\/-dumprange}
9092 Will create a dump of iCode's, after live range analysis
9093 \begin_inset LatexCommand \index{Live range analysis}
9099 <source filename>.dumprange.
9101 \labelwidthstring 00.00.0000
9116 \begin_inset LatexCommand \index{-\/-dumlrange}
9122 Will dump the life ranges
9123 \begin_inset LatexCommand \index{Live range analysis}
9129 \labelwidthstring 00.00.0000
9144 \begin_inset LatexCommand \index{-\/-dumpregassign}
9153 Will create a dump of iCode's, after register assignment
9154 \begin_inset LatexCommand \index{Register assignment}
9160 <source filename>.dumprassgn.
9162 \labelwidthstring 00.00.0000
9177 \begin_inset LatexCommand \index{-\/-dumplrange}
9183 Will create a dump of the live ranges of iTemp's
9185 \added_space_bottom bigskip \labelwidthstring 00.00.0000
9200 \begin_inset LatexCommand \index{-\/-dumpall}
9211 Will cause all the above mentioned dumps to be created.
9214 Redirecting output on Windows Shells
9216 \added_space_bottom bigskip
9217 By default SDCC writes it's error messages to
9218 \begin_inset Quotes sld
9222 \begin_inset Quotes srd
9226 To force all messages to
9227 \begin_inset Quotes sld
9231 \begin_inset Quotes srd
9255 \begin_inset LatexCommand \index{-\/-use-stdout}
9260 Additionally, if you happen to have visual studio installed in your windows
9261 machine, you can use it to compile your sources using a custom build and
9277 \begin_inset LatexCommand \index{-\/-vc}
9282 Something like this should work:
9326 -model-large -c $(InputPath)
9329 Environment variables
9330 \begin_inset LatexCommand \index{Environment variables}
9337 SDCC recognizes the following environment variables:
9339 \labelwidthstring 00.00.0000
9344 \begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
9350 SDCC installs a signal handler
9351 \begin_inset LatexCommand \index{signal handler}
9355 to be able to delete temporary files after an user break (^C) or an exception.
9356 If this environment variable is set, SDCC won't install the signal handler
9357 in order to be able to debug SDCC.
9359 \labelwidthstring 00.00.0000
9366 \begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
9372 Path, where temporary files will be created.
9373 The order of the variables is the search order.
9374 In a standard *nix environment these variables are not set, and there's
9375 no need to set them.
9376 On Windows it's recommended to set one of them.
9378 \labelwidthstring 00.00.0000
9383 \begin_inset LatexCommand \index{SDCC\_HOME}
9390 \begin_inset LatexCommand \ref{sub:Install-paths}
9396 \begin_inset Quotes sld
9400 \begin_inset Quotes srd
9405 \labelwidthstring 00.00.0000
9410 \begin_inset LatexCommand \index{SDCC\_INCLUDE}
9417 \begin_inset LatexCommand \ref{sub:Search-Paths}
9423 \begin_inset Quotes sld
9427 \begin_inset Quotes srd
9432 \labelwidthstring 00.00.0000
9437 \begin_inset LatexCommand \index{SDCC\_LIB}
9444 \begin_inset LatexCommand \ref{sub:Search-Paths}
9450 \begin_inset Quotes sld
9454 \begin_inset Quotes srd
9459 \added_space_bottom bigskip
9460 There are some more environment variables recognized by SDCC, but these
9461 are solely used for debugging purposes.
9462 They can change or disappear very quickly, and will never be documented.
9465 Storage Class Language Extensions
9468 MCS51/DS390 Storage Class
9469 \begin_inset LatexCommand \index{Storage class}
9476 In addition to the ANSI storage classes SDCC allows the following MCS51
9477 specific storage classes:
9478 \layout Subsubsection
9481 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
9486 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
9491 \begin_inset LatexCommand \index{near (storage class)}
9496 \begin_inset LatexCommand \index{\_\_near (storage class)}
9507 storage class for the Small Memory model (
9515 or the more ANSI-C compliant forms
9523 can be used synonymously).
9524 Variables declared with this storage class will be allocated in the directly
9525 addressable portion of the internal RAM of a 8051, e.g.:
9530 __data unsigned char test_data;
9533 Writing 0x01 to this variable generates the assembly code:
9538 75*00 01\SpecialChar ~
9544 \layout Subsubsection
9547 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9552 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
9557 \begin_inset LatexCommand \index{far (storage class)}
9562 \begin_inset LatexCommand \index{\_\_far (storage class)}
9569 Variables declared with this storage class will be placed in the external
9575 storage class for the Large Memory model, e.g.:
9580 __xdata unsigned char test_xdata;
9583 Writing 0x01 to this variable generates the assembly code:
9588 90s00r00\SpecialChar ~
9617 \layout Subsubsection
9620 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
9625 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
9632 Variables declared with this storage class will be allocated into the indirectly
9633 addressable portion of the internal ram of a 8051, e.g.:
9638 __idata unsigned char test_idata;
9641 Writing 0x01 to this variable generates the assembly code:
9670 Please note, the first 128 byte of idata physically access the same RAM
9672 The original 8051 had 128 byte idata memory, nowadays most devices have
9673 256 byte idata memory.
9675 \begin_inset LatexCommand \index{stack}
9679 is located in idata memory.
9680 \layout Subsubsection
9683 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
9688 \begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
9695 Paged xdata access is just as straightforward as using the other addressing
9697 It is typically located at the start of xdata and has a maximum size of
9699 The following example writes 0x01 to the pdata variable.
9700 Please note, pdata access physically accesses xdata memory.
9701 The high byte of the address is determined by port P2
9702 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
9706 (or in case of some 8051 variants by a separate Special Function Register,
9708 \begin_inset LatexCommand \ref{sub:MCS51-variants}
9717 storage class for the Medium Memory model, e.g.:
9722 __pdata unsigned char test_pdata;
9725 Writing 0x01 to this variable generates the assembly code:
9769 \begin_inset LatexCommand \index{-\/-xstack}
9773 option is used the pdata memory area is followed by the xstack memory area
9774 and the sum of their sizes is limited to 256 bytes.
9775 \layout Subsubsection
9778 \begin_inset LatexCommand \index{code}
9783 \begin_inset LatexCommand \index{\_\_code}
9790 'Variables' declared with this storage class will be placed in the code
9796 __code unsigned char test_code;
9799 Read access to this variable generates the assembly code:
9804 90s00r6F\SpecialChar ~
9807 mov dptr,#_test_code
9836 indexed arrays of characters in code memory can be accessed efficiently:
9841 __code char test_array[] = {'c','h','e','a','p'};
9844 Read access to this array using an 8-bit unsigned index generates the assembly
9861 90s00r41\SpecialChar ~
9864 mov dptr,#_test_array
9879 \layout Subsubsection
9882 \begin_inset LatexCommand \index{bit}
9887 \begin_inset LatexCommand \index{\_\_bit}
9894 This is a data-type and a storage class specifier.
9895 When a variable is declared as a bit, it is allocated into the bit addressable
9896 memory of 8051, e.g.:
9904 Writing 1 to this variable generates the assembly code:
9920 The bit addressable memory consists of 128 bits which are located from 0x20
9921 to 0x2f in data memory.
9924 Apart from this 8051 specific storage class most architectures support ANSI-C
9926 \begin_inset LatexCommand \index{bitfields}
9936 Not really meant as examples, but nevertheless showing what bitfields are
9937 about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
9941 In accordance with ISO/IEC 9899 bits and bitfields without an explicit
9942 signed modifier are implemented as unsigned.
9943 \layout Subsubsection
9946 \begin_inset LatexCommand \index{sfr}
9951 \begin_inset LatexCommand \index{\_\_sfr}
9956 \begin_inset LatexCommand \index{sfr16}
9961 \begin_inset LatexCommand \index{\_\_sfr16}
9966 \begin_inset LatexCommand \index{sfr32}
9971 \begin_inset LatexCommand \index{\_\_sfr32}
9976 \begin_inset LatexCommand \index{\_\_sbit}
9981 \begin_inset LatexCommand \index{sbit}
9988 Like the bit keyword,
9990 sfr / sfr16 / sfr32 / sbit
9992 signify both a data-type and storage class, they are used to describe the
10013 variables of a 8051, eg:
10019 \begin_inset LatexCommand \index{at}
10024 \begin_inset LatexCommand \index{\_\_at}
10028 (0x80) P0;\SpecialChar ~
10029 /* special function register P0 at location 0x80 */
10033 /* 16 bit special function register combination for timer 0
10037 with the high byte at location 0x8C and the low byte at location 0x8A */
10039 __sfr16 __at (0x8C8A) TMR0;
10044 \begin_inset LatexCommand \index{at}
10049 \begin_inset LatexCommand \index{\_\_at}
10053 (0xd7) CY;\SpecialChar ~
10055 \begin_inset LatexCommand \index{Flags}
10060 \begin_inset LatexCommand \index{Carry flag}
10067 Special function registers which are located on an address dividable by
10068 8 are bit-addressable, an
10072 addresses a specific bit within these sfr.
10074 16 Bit and 32 bit special function register combinations which require a
10075 certain access order are better not declared using
10084 Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
10085 this is not guaranteed.
10090 Please note, if you use a header file which was written for another compiler
10091 then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
10097 Specifically the syntax
10100 sfr P0 = 0x80;\SpecialChar ~
10107 by SDCC to an assignment of 0x80 to a variable called P0
10110 \begin_inset Marginal
10124 Nevertheless it is possible to write header files
10125 \begin_inset LatexCommand \index{Header files}
10130 \begin_inset LatexCommand \index{Include files}
10134 which can be shared among different compilers (see section
10135 \begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}
10141 \layout Subsubsection
10144 \begin_inset LatexCommand \index{Pointer}
10148 to MCS51/DS390 specific memory spaces
10151 SDCC allows (via language extensions) pointers to explicitly point to any
10152 of the memory spaces
10153 \begin_inset LatexCommand \index{Memory model}
10158 In addition to the explicit pointers, the compiler uses (by default) generic
10159 pointers which can be used to point to any of the memory spaces.
10163 Pointer declaration examples:
10168 /* pointer physically in internal ram pointing to object in external ram
10171 __xdata unsigned char * __data p;
10175 /* pointer physically in external ram pointing to object in internal ram
10178 __data unsigned char * __xdata p;
10182 /* pointer physically in code rom pointing to data in xdata space */
10184 __xdata unsigned char * __code p;
10188 /* pointer physically in code space pointing to data in code space */
10190 __code unsigned char * __code p;
10194 /* generic pointer physically located in xdata space */
10196 unsigned char * __xdata p;
10200 /* generic pointer physically located in default memory space */
10206 /* the following is a function pointer
10207 \begin_inset LatexCommand \index{function pointer}
10211 physically located in data space */
10213 char (* __data fp)(void);
10216 Well you get the idea.
10221 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
10234 The highest order byte of the
10238 pointers contains the data space information.
10239 Assembler support routines are called whenever data is stored or retrieved
10245 These are useful for developing reusable library
10246 \begin_inset LatexCommand \index{Libraries}
10251 Explicitly specifying the pointer
10252 \begin_inset LatexCommand \index{pointer}
10256 type will generate the most efficient code.
10257 \layout Subsubsection
10259 Notes on MCS51 memory
10260 \begin_inset LatexCommand \index{MCS51 memory}
10267 The 8051 family of microcontrollers have a minimum of 128 bytes of internal
10268 RAM memory which is structured as follows:
10272 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
10275 - Bytes 20-2F - 16 bytes to hold 128 bit
10276 \begin_inset LatexCommand \index{bit}
10282 - Bytes 30-7F - 80 bytes for general purpose use.
10287 Additionally some members of the MCS51 family may have up to 128 bytes of
10288 additional, indirectly addressable, internal RAM memory (
10293 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
10298 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
10303 Furthermore, some chips may have some built in external memory (
10308 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10313 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10317 ) which should not be confused with the internal, directly addressable RAM
10323 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
10328 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
10333 Sometimes this built in
10337 memory has to be activated before using it (you can probably find this
10338 information on the datasheet of the microcontroller your are using, see
10340 \begin_inset LatexCommand \ref{sub:Startup-Code}
10348 Normally SDCC will only use the first bank
10349 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
10353 of registers (register bank 0), but it is possible to specify that other
10354 banks of registers (keyword
10361 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
10366 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
10372 ) should be used in interrupt
10373 \begin_inset LatexCommand \index{interrupt}
10378 \begin_inset LatexCommand \index{\_\_interrupt}
10383 By default, the compiler will place the stack after the last byte of allocated
10384 memory for variables.
10385 For example, if the first 2 banks of registers are used, and only four
10390 variables, it will position the base of the internal stack at address 20
10392 This implies that as the stack
10393 \begin_inset LatexCommand \index{stack}
10397 grows, it will use up the remaining register banks, and the 16 bytes used
10398 by the 128 bit variables, and 80 bytes for general purpose use.
10399 If any bit variables are used, the data variables will be placed in unused
10400 register banks and after the byte holding the last bit variable.
10401 For example, if register banks 0 and 1 are used, and there are 9 bit variables
10406 variables will be placed starting from address 0x10 to 0x20 and continue
10419 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
10423 to specify the start address of the
10438 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
10442 to specify the size of the total internal RAM (
10456 By default the 8051 linker will place the stack after the last byte of (i)data
10469 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
10473 allows you to specify the start of the stack, i.e.
10474 you could start it after any data in the general purpose area.
10475 If your microcontroller has additional indirectly addressable internal
10480 ) you can place the stack on it.
10481 You may also need to use -
10492 \begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
10496 to set the start address of the external RAM (
10511 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
10515 to specify its size.
10516 Same goes for the code memory, using -
10527 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
10542 \begin_inset LatexCommand \index{-\/-code-size <Value>}
10547 If in doubt, don't specify any options and see if the resulting memory
10548 layout is appropriate, then you can adjust it.
10550 \added_space_bottom bigskip
10551 The linker generates two files with memory allocation information.
10552 The first, with extension .map
10553 \begin_inset LatexCommand \index{<file>.map}
10557 shows all the variables and segments.
10558 The second with extension .mem
10559 \begin_inset LatexCommand \index{<file>.mem}
10563 shows the final memory layout.
10564 The linker will complain either if memory segments overlap, there is not
10565 enough memory, or there is not enough space for stack.
10566 If you get any linking warnings and/or errors related to stack or segments
10567 allocation, take a look at either the .map or .mem files to find out what
10569 The .mem file may even suggest a solution to the problem.
10572 Z80/Z180 Storage Class
10573 \begin_inset LatexCommand \index{Z80!Storage class}
10577 Language Extensions
10578 \layout Subsubsection
10581 \begin_inset LatexCommand \index{sfr}
10586 \begin_inset LatexCommand \index{\_\_sfr}
10590 (in/out to 8-bit addresses)
10594 \begin_inset LatexCommand \index{Z80}
10598 family has separate address spaces for memory and
10608 \begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
10613 \begin_inset LatexCommand \index{Z80!I/O memory}
10618 \begin_inset LatexCommand \index{Z180!I/O memory}
10622 is accessed with special instructions, e.g.:
10627 sfr at 0x78 IoPort;\SpecialChar ~
10629 /* define a var in I/O space at 78h called IoPort */
10633 Writing 0x01 to this variable generates the assembly code:
10638 3E 01\SpecialChar ~
10646 D3 78\SpecialChar ~
10653 \layout Subsubsection
10656 \begin_inset LatexCommand \index{sfr}
10661 \begin_inset LatexCommand \index{\_\_sfr}
10665 (in/out to 16-bit addresses)
10672 is used to support 16 bit addresses in I/O memory e.g.:
10678 \begin_inset LatexCommand \index{at}
10683 \begin_inset LatexCommand \index{\_\_at}
10690 Writing 0x01 to this variable generates the assembly code:
10695 01 23 01\SpecialChar ~
10700 3E 01\SpecialChar ~
10708 ED 79\SpecialChar ~
10715 \layout Subsubsection
10718 \begin_inset LatexCommand \index{sfr}
10723 \begin_inset LatexCommand \index{\_\_sfr}
10727 (in0/out0 to 8 bit addresses on Z180
10728 \begin_inset LatexCommand \index{Z180}
10733 \begin_inset LatexCommand \index{HD64180 (see Z180)}
10739 \added_space_bottom bigskip
10740 The compiler option -
10751 \begin_inset LatexCommand \index{Z180!Options!-\/-portmode}
10755 =180 (80) and a compiler #pragma\SpecialChar ~
10757 \begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}
10761 z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
10771 If you include the file z180.h this will be set automatically.
10775 \begin_inset LatexCommand \index{HC08!Storage class}
10779 Language Extensions
10780 \layout Subsubsection
10783 \begin_inset LatexCommand \index{data (hc08 storage class)}
10788 \begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
10795 The data storage class declares a variable that resides in the first 256
10796 bytes of memory (the direct page).
10798 \begin_inset LatexCommand \index{HC08}
10802 is most efficient at accessing variables (especially pointers) stored here.
10803 \layout Subsubsection
10806 \begin_inset LatexCommand \index{xdata (hc08 storage class)}
10811 \begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
10817 \added_space_bottom bigskip
10818 The xdata storage class declares a variable that can reside anywhere in
10820 This is the default if no storage class is specified.
10824 Absolute Addressing
10825 \begin_inset LatexCommand \index{Absolute addressing}
10832 Data items can be assigned an absolute address with the
10835 \begin_inset LatexCommand \index{at}
10840 \begin_inset LatexCommand \index{\_\_at}
10846 keyword, in addition to a storage class, e.g.:
10852 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10857 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
10862 \begin_inset LatexCommand \index{at}
10867 \begin_inset LatexCommand \index{\_\_at}
10871 0x7ffe unsigned int chksum;
10874 or, better conforming to ISO/IEC 9899 C:
10879 __xdata __at (0x7ffe) unsigned int chksum;
10882 In the above example the variable chksum will be located at 0x7ffe and 0x7fff
10883 of the external ram.
10888 reserve any space for variables declared in this way
10889 \begin_inset Marginal
10900 (they are implemented with an equate in the assembler).
10901 Thus it is left to the programmer to make sure there are no overlaps with
10902 other variables that are declared without the absolute address.
10903 The assembler listing file (.lst
10904 \begin_inset LatexCommand \index{<file>.lst}
10908 ) and the linker output files (.rst
10909 \begin_inset LatexCommand \index{<file>.rst}
10914 \begin_inset LatexCommand \index{<file>.map}
10918 ) are good places to look for such overlaps.
10919 Variables with an absolute address are
10922 \begin_inset Marginal
10936 \begin_inset LatexCommand \index{Variable initialization}
10943 In case of memory mapped I/O devices the keyword
10947 has to be used to tell the compiler that accesses might not be removed:
10953 \begin_inset LatexCommand \index{volatile}
10958 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
10963 \begin_inset LatexCommand \index{at}
10967 (0x8000) unsigned char PORTA_8255;
10970 For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
10975 \begin_inset LatexCommand \index{Aligned array}
10982 starts at a block (256 byte) boundary
10983 \begin_inset LatexCommand \index{block boundary}
10988 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
10994 Absolute addresses can be specified for variables in all storage classes,
11001 \begin_inset LatexCommand \index{bit}
11006 \begin_inset LatexCommand \index{at}
11013 The above example will allocate the variable at offset 0x02 in the bit-addressab
11015 There is no real advantage to assigning absolute addresses to variables
11016 in this manner, unless you want strict control over all the variables allocated.
11017 One possible use would be to write hardware portable code.
11018 For example, if you have a routine that uses one or more of the microcontroller
11019 I/O pins, and such pins are different for two different hardwares, you
11020 can declare the I/O pins in your routine using:
11026 \begin_inset LatexCommand \index{volatile}
11030 __bit MOSI;\SpecialChar ~
11034 /* master out, slave in */
11036 extern volatile __bit MISO;\SpecialChar ~
11040 /* master in, slave out */
11042 extern volatile __bit MCLK;\SpecialChar ~
11050 /* Input and Output of a byte on a 3-wire serial bus.
11055 If needed adapt polarity of clock, polarity of data and bit order
11060 unsigned char spi_io(unsigned char out_byte)
11084 MOSI = out_byte & 0x80;
11114 /* _asm nop _endasm; */\SpecialChar ~
11122 /* for slow peripherals */
11173 Then, someplace in the code for the first hardware you would use
11179 \begin_inset LatexCommand \index{at}
11184 \begin_inset LatexCommand \index{\_\_at}
11188 (0x80) MOSI;\SpecialChar ~
11192 /* I/O port 0, bit 0 */
11194 __bit __at (0x81) MISO;\SpecialChar ~
11198 /* I/O port 0, bit 1 */
11200 __bit __at (0x82) MCLK;\SpecialChar ~
11204 /* I/O port 0, bit 2 */
11207 Similarly, for the second hardware you would use
11212 __bit __at (0x83) MOSI;\SpecialChar ~
11216 /* I/O port 0, bit 3 */
11218 __bit __at (0x91) MISO;\SpecialChar ~
11222 /* I/O port 1, bit 1 */
11225 \begin_inset LatexCommand \index{bit}
11229 __at (0x92) MCLK;\SpecialChar ~
11233 /* I/O port 1, bit 2 */
11235 \added_space_bottom bigskip
11236 and you can use the same hardware dependent routine without changes, as
11237 for example in a library.
11238 This is somehow similar to sbit, but only one absolute address has to be
11239 specified in the whole project.
11243 \begin_inset LatexCommand \index{Parameters}
11248 \begin_inset LatexCommand \index{function parameter}
11253 \begin_inset LatexCommand \index{local variables}
11258 \begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
11265 Automatic (local) variables and parameters to functions can either be placed
11266 on the stack or in data-space.
11267 The default action of the compiler is to place these variables in the internal
11268 RAM (for small model) or external RAM (for large model).
11269 This in fact makes them similar to
11272 \begin_inset LatexCommand \index{static}
11278 so by default functions are non-reentrant
11279 \begin_inset LatexCommand \index{reentrant}
11288 They can be placed on the stack
11289 \begin_inset LatexCommand \index{stack}
11306 \begin_inset LatexCommand \index{-\/-stack-auto}
11314 #pragma\SpecialChar ~
11318 \begin_inset LatexCommand \index{\#pragma stackauto}
11325 \begin_inset LatexCommand \index{reentrant}
11331 keyword in the function declaration, e.g.:
11336 unsigned char foo(char i) __reentrant
11350 Since stack space on 8051 is limited, the
11368 option should be used sparingly.
11369 Note that the reentrant keyword just means that the parameters & local
11370 variables will be allocated to the stack, it
11374 mean that the function is register bank
11375 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
11384 \begin_inset LatexCommand \index{local variables}
11388 can be assigned storage classes and absolute
11389 \begin_inset LatexCommand \index{Absolute addressing}
11398 unsigned char foo()
11406 __xdata unsigned char i;
11419 \begin_inset LatexCommand \index{at}
11423 (0x31) unsigned char j;
11435 In the above example the variable
11439 will be allocated in the external ram,
11443 in bit addressable space and
11462 or when a function is declared as
11466 this should only be done for static variables.
11470 \begin_inset LatexCommand \index{function parameter}
11474 however are not allowed any storage class
11475 \begin_inset LatexCommand \index{Storage class}
11479 , (storage classes for parameters will be ignored), their allocation is
11480 governed by the memory model in use, and the reentrancy options.
11483 It is however allowed to use bit parameters in reentrant functions and also
11484 non-static local bit variables are supported.
11485 Efficient use is limited to 8 semi-bitregisters in bit space.
11486 They are pushed and popped to stack
11487 \begin_inset LatexCommand \index{stack}
11491 as a single byte just like the normal registers.
11495 \begin_inset LatexCommand \label{sub:Overlaying}
11500 \begin_inset LatexCommand \index{Overlaying}
11508 \begin_inset LatexCommand \index{reentrant}
11512 functions SDCC will try to reduce internal ram space usage by overlaying
11513 parameters and local variables of a function (if possible).
11514 Parameters and local variables
11515 \begin_inset LatexCommand \index{local variables}
11519 of a function will be allocated to an overlayable segment if the function
11522 no other function calls and the function is non-reentrant and the memory
11524 \begin_inset LatexCommand \index{Memory model}
11531 If an explicit storage class
11532 \begin_inset LatexCommand \index{Storage class}
11536 is specified for a local variable, it will NOT be overlayed.
11539 Note that the compiler (not the linkage editor) makes the decision for overlayin
11541 Functions that are called from an interrupt service routine
11542 \begin_inset Marginal
11552 should be preceded by a #pragma\SpecialChar ~
11554 \begin_inset LatexCommand \index{\#pragma nooverlay}
11558 if they are not reentrant.
11561 Also note that the compiler does not do any processing of inline assembler
11562 code, so the compiler might incorrectly assign local variables and parameters
11563 of a function into the overlay segment if the inline assembler code calls
11564 other c-functions that might use the overlay.
11565 In that case the #pragma\SpecialChar ~
11566 nooverlay should be used.
11569 Parameters and local variables of functions that contain 16 or 32 bit multiplica
11571 \begin_inset LatexCommand \index{Multiplication}
11576 \begin_inset LatexCommand \index{Division}
11580 will NOT be overlayed since these are implemented using external functions,
11589 \begin_inset LatexCommand \index{\#pragma nooverlay}
11595 void set_error(unsigned char errcd)
11611 void some_isr () __interrupt
11612 \begin_inset LatexCommand \index{interrupt}
11641 \added_space_bottom bigskip
11642 In the above example the parameter
11650 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
11652 not present, this could cause unpredictable runtime behavior when called
11653 from an interrupt service routine.
11654 The #pragma\SpecialChar ~
11655 nooverlay ensures that the parameters and local variables for
11656 the function are NOT overlayed.
11659 Interrupt Service Routines
11660 \begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
11667 General Information
11682 outines to be coded in C, with some extended keywords.
11687 void timer_isr (void) __interrupt (1) __using (1)
11701 The optional number following the
11704 \begin_inset LatexCommand \index{interrupt}
11709 \begin_inset LatexCommand \index{\_\_interrupt}
11715 keyword is the interrupt number this routine will service.
11716 When present, the compiler will insert a call to this routine in the interrupt
11718 \begin_inset LatexCommand \index{interrupt vector table}
11722 for the interrupt number specified.
11723 If you have multiple source files in your project, interrupt service routines
11724 can be present in any of them, but a prototype of the isr MUST be present
11725 or included in the file that contains the function
11730 The optional (8051 specific) keyword
11733 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
11738 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
11744 can be used to tell the compiler to use the specified register bank when
11745 generating code for this function.
11748 Interrupt service routines open the door for some very interesting bugs:
11749 \layout Subsubsection
11752 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}
11756 Common interrupt pitfall: variable not declared
11761 If an interrupt service routine changes variables which are accessed by
11762 other functions these variables have to be declared
11767 \begin_inset LatexCommand \index{volatile}
11773 \begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}
11778 \layout Subsubsection
11781 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}
11785 Common interrupt pitfall:
11790 If the access to these variables is not
11793 \begin_inset LatexCommand \index{atomic}
11800 the processor needs more than one instruction for the access and could
11801 be interrupted while accessing the variable) the interrupt must be disabled
11802 during the access to avoid inconsistent data.
11805 Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs and
11806 should be protected by disabling interrupts.
11807 You're not automatically on the safe side if you use 8 bit variables though.
11808 We need an example here: f.e.
11809 on the 8051 the harmless looking
11810 \begin_inset Quotes srd
11815 flags\SpecialChar ~
11820 \begin_inset Quotes sld
11829 \begin_inset Quotes srd
11834 flags\SpecialChar ~
11839 \begin_inset Quotes sld
11842 from within an interrupt routine might get lost if the interrupt occurs
11845 \begin_inset Quotes sld
11850 counter\SpecialChar ~
11855 \begin_inset Quotes srd
11858 is not atomic on the 8051 even if
11862 is located in data memory.
11864 Bugs like these are hard to reproduce and can cause a lot of trouble.
11866 \layout Subsubsection
11869 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}
11873 Common interrupt pitfall:
11878 The return address and the registers used in the interrupt service routine
11879 are saved on the stack
11880 \begin_inset LatexCommand \index{stack}
11884 so there must be sufficient stack space.
11885 If there isn't variables or registers (or even the return address itself)
11892 \begin_inset LatexCommand \index{stack overflow}
11896 is most likely to happen if the interrupt occurs during the
11897 \begin_inset Quotes sld
11901 \begin_inset Quotes srd
11904 subroutine when the stack is already in use for f.e.
11905 many return addresses.
11906 \layout Subsubsection
11909 \begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}
11913 Common interrupt pitfall:
11915 use of non-reentrant functions
11918 A special note here, int (16 bit) and long (32 bit) integer division
11919 \begin_inset LatexCommand \index{Division}
11924 \begin_inset LatexCommand \index{Multiplication}
11929 \begin_inset LatexCommand \index{Modulus}
11934 \begin_inset LatexCommand \index{Floating point support}
11938 operations are implemented using external support routines.
11939 If an interrupt service routine needs to do any of these operations then
11940 the support routines (as mentioned in a following section) will have to
11941 be recompiled using the
11954 \begin_inset LatexCommand \index{-\/-stack-auto}
11960 option and the source file will need to be compiled using the
11975 \begin_inset LatexCommand \index{-\/-int-long-reent}
11982 Note, the type promotion
11983 \begin_inset LatexCommand \index{type promotion}
11987 required by ANSI C can cause 16 bit routines to be used
11988 \begin_inset Marginal
11999 without the programmer being aware of it.
12003 (unsigned char)(tail-1)
12005 within the if clause in section
12006 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
12012 \added_space_bottom bigskip
12013 Calling other functions from an interrupt service routine is not recommended,
12014 avoid it if possible.
12015 Note that when some function is called from an interrupt service routine
12016 it should be preceded by a #pragma\SpecialChar ~
12018 \begin_inset LatexCommand \index{\#pragma nooverlay}
12022 if it is not reentrant.
12023 Furthermore nonreentrant functions should not be called from the main program
12024 while the interrupt service routine might be active.
12025 They also must not be called from low priority interrupt service routines
12026 while a high priority interrupt service routine might be active.
12027 You could use semaphores or make the function
12031 if all parameters are passed in registers.
12034 \begin_inset LatexCommand \ref{sub:Overlaying}
12039 about Overlaying and section
12040 \begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
12045 about Functions using private register banks.
12048 MCS51/DS390 Interrupt Service Routines
12052 \begin_inset LatexCommand \index{interrupt}
12056 numbers and the corresponding address & descriptions for the Standard 8051/8052
12058 SDCC will automatically adjust the
12059 \begin_inset LatexCommand \index{interrupt vector table}
12063 to the maximum interrupt number specified.
12069 \begin_inset Tabular
12070 <lyxtabular version="3" rows="9" columns="3">
12072 <column alignment="center" valignment="top" leftline="true" width="0in">
12073 <column alignment="left" valignment="top" leftline="true" width="0in">
12074 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
12075 <row topline="true" bottomline="true">
12076 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12084 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12092 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12101 <row topline="true">
12102 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12110 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12118 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12127 <row topline="true">
12128 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12136 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12144 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12153 <row topline="true">
12154 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12162 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12170 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12179 <row topline="true">
12180 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12188 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12196 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12205 <row topline="true">
12206 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12214 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12222 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12231 <row topline="true">
12232 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12240 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12248 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12257 <row topline="true">
12258 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12266 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12273 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12282 <row topline="true" bottomline="true">
12283 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12291 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12298 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12316 If the interrupt service routine is defined without
12319 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12324 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12330 a register bank or with register bank 0 (
12334 0), the compiler will save the registers used by itself on the stack upon
12335 entry and restore them at exit, however if such an interrupt service routine
12336 calls another function then the entire register bank will be saved on the
12338 This scheme may be advantageous for small interrupt service routines which
12339 have low register usage.
12341 \added_space_bottom bigskip
12342 If the interrupt service routine is defined to be using a specific register
12347 & psw are saved and restored, if such an interrupt service routine calls
12348 another function (using another register bank) then the entire register
12349 bank of the called function will be saved on the stack
12350 \begin_inset LatexCommand \index{stack}
12355 This scheme is recommended for larger interrupt service routines.
12359 \begin_inset LatexCommand \index{HC08}
12363 Interrupt Service Routines
12365 \added_space_bottom bigskip
12366 Since the number of interrupts
12367 \begin_inset LatexCommand \index{HC08!interrupt}
12371 available is chip specific and the interrupt vector table always ends at
12372 the last byte of memory, the interrupt numbers corresponds to the interrupt
12373 vectors in reverse order of address.
12374 For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
12375 2 will use the interrupt vector at 0xfffa, and so on.
12376 However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
12377 this way; instead see section
12378 \begin_inset LatexCommand \ref{sub:Startup-Code}
12382 for details on customizing startup.
12385 Z80 Interrupt Service Routines
12389 \begin_inset LatexCommand \index{Z80}
12393 uses several different methods for determining the correct interrupt
12394 \begin_inset LatexCommand \index{Z80!interrupt}
12398 vector depending on the hardware implementation.
12399 Therefore, SDCC ignores the optional interrupt number and does not attempt
12400 to generate an interrupt vector table.
12403 By default, SDCC generates code for a maskable interrupt, which uses a RETI
12404 instruction to return from the interrupt.
12405 To write an interrupt handler for the non-maskable interrupt, which needs
12406 a RETN instruction instead, add the
12415 void nmi_isr (void) critical interrupt
12428 \added_space_bottom bigskip
12429 However if you need to create a non-interruptable interrupt service routine
12430 you would also require the
12435 To distinguish between this and an nmi_isr you must provide an interrupt
12439 Enabling and Disabling Interrupts
12442 Critical Functions and Critical Statements
12445 A special keyword may be associated with a block or a function declaring
12451 SDCC will generate code to disable all interrupts
12452 \begin_inset LatexCommand \index{interrupt}
12456 upon entry to a critical function and restore the interrupt enable to the
12457 previous state before returning.
12458 Nesting critical functions will need one additional byte on the stack
12459 \begin_inset LatexCommand \index{stack}
12468 int foo () __critical
12469 \begin_inset LatexCommand \index{critical}
12474 \begin_inset LatexCommand \index{\_\_critical}
12499 The critical attribute maybe used with other attributes like
12509 may also be used to disable interrupts more locally:
12517 More than one statement could have been included in the block.
12520 Enabling and Disabling Interrupts directly
12524 \begin_inset LatexCommand \index{interrupt}
12528 can also be disabled and enabled directly (8051):
12533 EA = 0;\SpecialChar ~
12596 EA = 1;\SpecialChar ~
12663 On other architectures which have seperate opcodes for enabling and disabling
12664 interrupts you might want to make use of defines with inline assembly
12665 \begin_inset LatexCommand \index{Assembler routines}
12670 \begin_inset LatexCommand \index{HC08!interrupt}
12680 \begin_inset LatexCommand \index{\_asm}
12689 \begin_inset LatexCommand \index{\_endasm}
12698 #define SEI _asm\SpecialChar ~
12710 Note: it is sometimes sufficient to disable only a specific interrupt source
12712 a timer or serial interrupt by manipulating an
12715 \begin_inset LatexCommand \index{interrupt mask}
12725 Usually the time during which interrupts are disabled should be kept as
12727 This minimizes both
12732 \begin_inset LatexCommand \index{interrupt latency}
12736 (the time between the occurrence of the interrupt and the execution of
12737 the first code in the interrupt routine) and
12742 \begin_inset LatexCommand \index{interrupt jitter}
12746 (the difference between the shortest and the longest interrupt latency).
12747 These really are something different, f.e.
12748 a serial interrupt has to be served before its buffer overruns so it cares
12749 for the maximum interrupt latency, whereas it does not care about jitter.
12750 On a loudspeaker driven via a digital to analog converter which is fed
12751 by an interrupt a latency of a few milliseconds might be tolerable, whereas
12752 a much smaller jitter will be very audible.
12755 You can reenable interrupts within an interrupt routine and on some architecture
12756 s you can make use of two (or more) levels of
12758 interrupt priorities
12761 \begin_inset LatexCommand \index{interrupt priority}
12766 On some architectures which don't support interrupt priorities these can
12767 be implemented by manipulating the interrupt mask and reenabling interrupts
12768 within the interrupt routine.
12769 Check there is sufficient space on the stack
12770 \begin_inset LatexCommand \index{stack}
12774 and don't add complexity unless you have to.
12779 \begin_inset LatexCommand \index{semaphore}
12783 locking (mcs51/ds390)
12786 Some architectures (mcs51/ds390) have an atomic
12787 \begin_inset LatexCommand \index{atomic}
12800 These type of instructions are typically used in preemptive multitasking
12801 systems, where a routine f.e.
12802 claims the use of a data structure ('acquires a lock
12803 \begin_inset LatexCommand \index{lock}
12807 on it'), makes some modifications and then releases the lock when the data
12808 structure is consistent again.
12809 The instruction may also be used if interrupt and non-interrupt code have
12810 to compete for a resource.
12811 With the atomic bit test and clear instruction interrupts
12812 \begin_inset LatexCommand \index{interrupt}
12816 don't have to be disabled for the locking operation.
12820 SDCC generates this instruction if the source follows this pattern:
12826 \begin_inset LatexCommand \index{volatile}
12830 bit resource_is_free;
12834 if (resource_is_free)
12844 resource_is_free=0;
12857 resource_is_free=1;
12864 Note, mcs51 and ds390 support only an atomic
12865 \begin_inset LatexCommand \index{atomic}
12873 instruction (as opposed to atomic bit test and
12878 Functions using private register banks
12879 \begin_inset LatexCommand \label{sub:Functions-using-private-banks}
12886 Some architectures have support for quickly changing register sets.
12887 SDCC supports this feature with the
12890 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
12895 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
12901 attribute (which tells the compiler to use a register bank
12902 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
12906 other than the default bank zero).
12907 It should only be applied to
12910 \begin_inset LatexCommand \index{interrupt}
12916 functions (see footnote below).
12917 This will in most circumstances make the generated ISR code more efficient
12918 since it will not have to save registers on the stack.
12925 attribute will have no effect on the generated code for a
12929 function (but may occasionally be useful anyway
12935 possible exception: if a function is called ONLY from 'interrupt' functions
12936 using a particular bank, it can be declared with the same 'using' attribute
12937 as the calling 'interrupt' functions.
12938 For instance, if you have several ISRs using bank one, and all of them
12939 call memcpy(), it might make sense to create a specialized version of memcpy()
12940 'using 1', since this would prevent the ISR from having to save bank zero
12941 to the stack on entry and switch to bank zero before calling the function
12948 (pending: Note, nowadays the
12952 attribute has an effect on
12956 the generated code for a
12971 function using a non-zero bank will assume that it can trash that register
12972 bank, and will not save it.
12973 Since high-priority interrupts
12974 \begin_inset LatexCommand \index{interrupts}
12979 \begin_inset LatexCommand \index{interrupt priority}
12983 can interrupt low-priority ones on the 8051 and friends, this means that
12984 if a high-priority ISR
12988 a particular bank occurs while processing a low-priority ISR
12992 the same bank, terrible and bad things can happen.
12993 To prevent this, no single register bank should be
12997 by both a high priority and a low priority ISR.
12998 This is probably most easily done by having all high priority ISRs use
12999 one bank and all low priority ISRs use another.
13000 If you have an ISR which can change priority at runtime, you're on your
13001 own: I suggest using the default bank zero and taking the small performance
13004 \added_space_bottom bigskip
13005 It is most efficient if your ISR calls no other functions.
13006 If your ISR must call other functions, it is most efficient if those functions
13007 use the same bank as the ISR (see note 1 below); the next best is if the
13008 called functions use bank zero.
13009 It is very inefficient to call a function using a different, non-zero bank
13015 \begin_inset LatexCommand \label{sub:Startup-Code}
13020 \begin_inset LatexCommand \index{Startup code}
13027 MCS51/DS390 Startup Code
13030 The compiler inserts a call to the C routine
13032 _sdcc_external_startup()
13033 \begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
13042 at the start of the CODE area.
13043 This routine is in the runtime library
13044 \begin_inset LatexCommand \index{Runtime library}
13049 By default this routine returns 0, if this routine returns a non-zero value,
13050 the static & global variable initialization will be skipped and the function
13051 main will be invoked.
13052 Otherwise static & global variables will be initialized before the function
13056 _sdcc_external_startup()
13058 routine to your program to override the default if you need to setup hardware
13059 or perform some other critical operation prior to static & global variable
13061 \begin_inset LatexCommand \index{Variable initialization}
13066 On some mcs51 variants xdata
13067 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
13071 memory has to be explicitly enabled before it can be accessed or if the
13073 \begin_inset LatexCommand \index{watchdog}
13077 needs to be disabled, this is the place to do it.
13078 The startup code clears all internal data memory, 256 bytes by default,
13079 but from 0 to n-1 if
13092 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
13099 (recommended for Chipcon CC1010).
13101 \added_space_bottom bigskip
13102 See also the compiler options
13121 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
13140 \begin_inset LatexCommand \index{-\/-main-return}
13145 \begin_inset LatexCommand \ref{sub:MCS51-variants}
13149 about MCS51-variants.
13154 \added_space_bottom bigskip
13156 \begin_inset LatexCommand \index{HC08}
13160 startup code follows the same scheme as the MCS51 startup code.
13165 \added_space_bottom bigskip
13167 \begin_inset LatexCommand \index{Z80}
13171 the startup code is inserted by linking with crt0.o which is generated from
13172 sdcc/device/lib/z80/crt0.s.
13173 If you need a different startup code you can use the compiler option
13194 \begin_inset LatexCommand \index{-\/-no-std-crt0}
13198 and provide your own crt0.o.
13202 Inline Assembler Code
13203 \begin_inset LatexCommand \index{Assembler routines}
13210 A Step by Step Introduction
13211 \begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}
13218 Starting from a small snippet of c-code this example shows for the MCS51
13219 how to use inline assembly, access variables, a function parameter and
13220 an array in xdata memory.
13221 The example uses an MCS51 here but is easily adapted for other architectures.
13222 This is a buffer routine which should be optimized:
13228 unsigned char __far
13229 \begin_inset LatexCommand \index{far (storage class)}
13234 \begin_inset LatexCommand \index{\_\_far (storage class)}
13239 \begin_inset LatexCommand \index{at}
13244 \begin_inset LatexCommand \index{\_\_at}
13248 (0x7f00) buf[0x100];
13249 \begin_inset LatexCommand \index{Aligned array}
13255 unsigned char head, tail;\SpecialChar ~
13273 \begin_inset LatexCommand \index{interrupt}
13325 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
13337 void to_buffer( unsigned char c )
13345 if( head != (unsigned char)(tail-1) )\SpecialChar ~
13351 \begin_inset LatexCommand \index{promotion to signed int}
13356 \begin_inset LatexCommand \index{type promotion}
13361 \begin_inset Marginal
13382 buf[ head++ ] = c;\SpecialChar ~
13398 /* access to a 256 byte aligned array */
13403 If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
13404 then a corresponding buffer.asm file is generated.
13405 We define a new function
13409 in file buffer.c in which we cut and paste the generated code, removing
13410 unwanted comments and some ':'.
13412 \begin_inset Quotes sld
13416 \begin_inset Quotes srd
13420 \begin_inset Quotes sld
13424 \begin_inset Quotes srd
13427 to the beginning and the end of the function body:
13433 /* With a cut and paste from the .asm file, we have something to start with.
13438 The function is not yet OK! (registers aren't saved) */
13440 void to_buffer_asm( unsigned char c )
13449 \begin_inset LatexCommand \index{\_asm}
13454 \begin_inset LatexCommand \index{\_\_asm}
13468 ;buffer.c if( head != (unsigned char)(tail-1) ) \SpecialChar ~
13474 \begin_inset LatexCommand \index{promotion to signed int}
13479 \begin_inset LatexCommand \index{type promotion}
13531 ;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
13532 \begin_inset LatexCommand \index{Aligned array}
13597 \begin_inset LatexCommand \index{\_endasm}
13602 \begin_inset LatexCommand \index{\_\_endasm}
13611 The new file buffer.c should compile with only one warning about the unreferenced
13612 function argument 'c'.
13613 Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
13614 (1) and finally have:
13620 unsigned char __far __at(0x7f00) buf[0x100];
13622 unsigned char head, tail;
13624 #define USE_ASSEMBLY (1)
13632 void to_buffer( unsigned char c )
13640 if( head != (unsigned char)(tail-1) )
13660 void to_buffer( unsigned char c )
13668 c; // to avoid warning: unreferenced function argument
13675 \begin_inset LatexCommand \index{\_asm}
13680 \begin_inset LatexCommand \index{\_\_asm}
13694 ; save used registers here.
13705 ; If we were still using r2,r3 we would have to push them here.
13708 ; if( head != (unsigned char)(tail-1) )
13751 ; we could do an ANL a,#0x0f here to use a smaller buffer (see below)
13775 ; buf[ head++ ] = c;
13786 a,dpl \SpecialChar ~
13793 ; dpl holds lower byte of function argument
13804 dpl,_head \SpecialChar ~
13807 ; buf is 0x100 byte aligned so head can be used directly
13849 ; we could do an ANL _head,#0x0f here to use a smaller buffer (see above)
13861 ; restore used registers here
13868 \begin_inset LatexCommand \index{\_endasm}
13873 \begin_inset LatexCommand \index{\_\_endasm}
13884 The inline assembler code can contain any valid code understood by the assembler
13885 , this includes any assembler directives and comment lines.
13886 The assembler does not like some characters like ':' or ''' in comments.
13887 You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
13888 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
13893 \begin_inset LatexCommand \index{Assembler documentation}
13898 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
13906 The compiler does not do any validation of the code within the
13909 \begin_inset LatexCommand \index{\_asm}
13914 \begin_inset LatexCommand \index{\_\_asm}
13922 \begin_inset LatexCommand \index{\_endasm}
13927 \begin_inset LatexCommand \index{\_\_endasm}
13936 Specifically it will not know which registers are used and thus register
13938 \begin_inset LatexCommand \index{push/pop}
13942 has to be done manually.
13946 It is recommended that each assembly instruction (including labels) be placed
13947 in a separate line (as the example shows).
13961 \begin_inset LatexCommand \index{-\/-peep-asm}
13967 command line option is used, the inline assembler code will be passed through
13968 the peephole optimizer
13969 \begin_inset LatexCommand \index{Peephole optimizer}
13974 There are only a few (if any) cases where this option makes sense, it might
13975 cause some unexpected changes in the inline assembler code.
13976 Please go through the peephole optimizer rules defined in file
13980 before using this option.
13984 \begin_inset LatexCommand \label{sub:Naked-Functions}
13989 \begin_inset LatexCommand \index{Naked functions}
13996 A special keyword may be associated with a function declaring it as
13999 \begin_inset LatexCommand \index{\_naked}
14004 \begin_inset LatexCommand \index{\_\_naked}
14015 function modifier attribute prevents the compiler from generating prologue
14016 \begin_inset LatexCommand \index{function prologue}
14021 \begin_inset LatexCommand \index{function epilogue}
14025 code for that function.
14026 This means that the user is entirely responsible for such things as saving
14027 any registers that may need to be preserved, selecting the proper register
14028 bank, generating the
14032 instruction at the end, etc.
14033 Practically, this means that the contents of the function must be written
14034 in inline assembler.
14035 This is particularly useful for interrupt functions, which can have a large
14036 (and often unnecessary) prologue/epilogue.
14037 For example, compare the code generated by these two functions:
14043 \begin_inset LatexCommand \index{volatile}
14047 data unsigned char counter;
14051 void simpleInterrupt(void) __interrupt
14052 \begin_inset LatexCommand \index{interrupt}
14057 \begin_inset LatexCommand \index{\_\_interrupt}
14075 void nakedInterrupt(void) __interrupt (2) __naked
14084 \begin_inset LatexCommand \index{\_asm}
14089 \begin_inset LatexCommand \index{\_\_asm}
14106 _counter ; does not change flags, no need to save psw
14118 ; MUST explicitly include ret or reti in _naked function.
14125 \begin_inset LatexCommand \index{\_endasm}
14130 \begin_inset LatexCommand \index{\_\_endasm}
14139 For an 8051 target, the generated simpleInterrupt looks like:
14148 example, recent versions of SDCC generate
14154 code for simpleInterrupt() and nakedInterrupt()!
14294 whereas nakedInterrupt looks like:
14309 _counter ; does not change flags, no need to save psw
14327 ; MUST explicitly include ret or reti in _naked function
14330 The related directive #pragma exclude
14331 \begin_inset LatexCommand \index{\#pragma exclude}
14335 allows a more fine grained control over pushing & popping
14336 \begin_inset LatexCommand \index{push/pop}
14343 While there is nothing preventing you from writing C code inside a
14347 function, there are many ways to shoot yourself in the foot doing this,
14348 and it is recommended that you stick to inline assembler.
14351 Use of Labels within Inline Assembler
14354 SDCC allows the use of in-line assembler with a few restrictions regarding
14356 In older versions of the compiler all labels defined within inline assembler
14365 where nnnn is a number less than 100 (which implies a limit of utmost 100
14366 inline assembler labels
14380 \begin_inset LatexCommand \index{\_asm}
14385 \begin_inset LatexCommand \index{\_\_asm}
14415 \begin_inset LatexCommand \index{\_endasm}
14420 \begin_inset LatexCommand \index{\_\_endasm}
14427 Inline assembler code cannot reference any C-Labels, however it can reference
14429 \begin_inset LatexCommand \index{Labels}
14433 defined by the inline assembler, e.g.:
14458 ; some assembler code
14478 /* some more c code */
14480 clabel:\SpecialChar ~
14482 /* inline assembler cannot reference this label */
14494 $0003: ;label (can be referenced by inline assembler only)
14501 \begin_inset LatexCommand \index{\_endasm}
14506 \begin_inset LatexCommand \index{\_\_endasm}
14516 /* some more c code */
14521 In other words inline assembly code can access labels defined in inline
14522 assembly within the scope of the function.
14523 The same goes the other way, i.e.
14524 labels defines in inline assembly can not be accessed by C statements.
14527 Interfacing with Assembler Code
14528 \begin_inset LatexCommand \index{Assembler routines}
14535 Global Registers used for Parameter Passing
14536 \begin_inset LatexCommand \index{Parameter passing}
14543 The compiler always uses the global registers
14546 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14551 \begin_inset LatexCommand \index{DPTR}
14556 \begin_inset LatexCommand \index{B (mcs51, ds390 register)}
14565 \begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}
14571 to pass the first parameter to a routine.
14572 The second parameter onwards is either allocated on the stack (for reentrant
14583 -stack-auto is used) or in data / xdata memory (depending on the memory
14588 Assembler Routine (non-reentrant)
14591 In the following example
14592 \begin_inset LatexCommand \index{reentrant}
14597 \begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
14601 the function c_func calls an assembler routine asm_func, which takes two
14603 \begin_inset LatexCommand \index{function parameter}
14612 extern int asm_func(unsigned char, unsigned char);
14616 int c_func (unsigned char i, unsigned char j)
14624 return asm_func(i,j);
14638 return c_func(10,9);
14643 The corresponding assembler function is:
14648 .globl _asm_func_PARM_2
14749 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
14766 Note here that the return values
14767 \begin_inset LatexCommand \index{return value}
14771 are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
14773 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
14774 b' & 'acc' for four byte values.
14777 The parameter naming convention is _<function_name>_PARM_<n>, where n is
14778 the parameter number starting from 1, and counting from the left.
14779 The first parameter is passed in
14780 \begin_inset Quotes eld
14784 \begin_inset Quotes erd
14787 for a one byte parameter,
14788 \begin_inset Quotes eld
14792 \begin_inset Quotes erd
14796 \begin_inset Quotes eld
14800 \begin_inset Quotes erd
14803 for three bytes and
14804 \begin_inset Quotes eld
14808 \begin_inset Quotes erd
14811 for a four bytes parameter.
14812 The variable name for the second parameter will be _<function_name>_PARM_2.
14816 Assemble the assembler routine with the following command:
14823 asx8051 -losg asmfunc.asm
14830 Then compile and link the assembler routine to the C source file with the
14838 sdcc cfunc.c asmfunc.rel
14841 Assembler Routine (reentrant)
14845 \begin_inset LatexCommand \index{reentrant}
14850 \begin_inset LatexCommand \index{Assembler routines (reentrant)}
14854 the second parameter
14855 \begin_inset LatexCommand \index{function parameter}
14859 onwards will be passed on the stack, the parameters are pushed from right
14861 after the call the leftmost parameter will be on the top of the stack.
14862 Here is an example:
14867 extern int asm_func(unsigned char, unsigned char);
14871 int c_func (unsigned char i, unsigned char j) reentrant
14879 return asm_func(i,j);
14893 return c_func(10,9);
14898 The corresponding assembler routine is:
14997 \added_space_bottom bigskip
14998 The compiling and linking procedure remains the same, however note the extra
14999 entry & exit linkage required for the assembler code, _bp is the stack
15000 frame pointer and is used to compute the offset into the stack for parameters
15001 and local variables.
15005 \begin_inset LatexCommand \index{int (16 bit)}
15010 \begin_inset LatexCommand \index{long (32 bit)}
15017 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
15018 multiplication and modulus operations are implemented by support routines.
15019 These support routines are all developed in ANSI-C to facilitate porting
15020 to other MCUs, although some model specific assembler optimizations are
15022 The following files contain the described routines, all of them can be
15023 found in <installdir>/share/sdcc/lib.
15029 \begin_inset Tabular
15030 <lyxtabular version="3" rows="11" columns="2">
15032 <column alignment="left" valignment="top" leftline="true" width="0">
15033 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
15034 <row topline="true" bottomline="true">
15035 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15045 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15056 <row topline="true">
15057 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15065 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15070 16 bit multiplication
15074 <row topline="true">
15075 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15083 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15088 signed 16 bit division (calls _divuint)
15092 <row topline="true">
15093 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15101 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15106 unsigned 16 bit division
15110 <row topline="true">
15111 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15119 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15124 signed 16 bit modulus (calls _moduint)
15128 <row topline="true">
15129 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15137 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15142 unsigned 16 bit modulus
15146 <row topline="true">
15147 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15155 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15160 32 bit multiplication
15164 <row topline="true">
15165 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15173 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15178 signed 32 division (calls _divulong)
15182 <row topline="true">
15183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15191 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15196 unsigned 32 division
15200 <row topline="true">
15201 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15209 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15214 signed 32 bit modulus (calls _modulong)
15218 <row topline="true" bottomline="true">
15219 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15227 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15232 unsigned 32 bit modulus
15245 Since they are compiled as
15250 \begin_inset LatexCommand \index{reentrant}
15255 \begin_inset LatexCommand \index{interrupt}
15259 service routines should not do any of the above operations.
15260 If this is unavoidable then the above routines will need to be compiled
15274 \begin_inset LatexCommand \index{-\/-stack-auto}
15280 option, after which the source program will have to be compiled with
15293 \begin_inset LatexCommand \index{-\/-int-long-reent}
15300 Notice that you don't have to call these routines directly.
15301 The compiler will use them automatically every time an integer operation
15305 Floating Point Support
15306 \begin_inset LatexCommand \index{Floating point support}
15313 SDCC supports IEEE (single precision 4 bytes) floating point numbers.
15314 The floating point support routines are derived from gcc's floatlib.c and
15315 consist of the following routines:
15323 \begin_inset Tabular
15324 <lyxtabular version="3" rows="17" columns="2">
15326 <column alignment="left" valignment="top" leftline="true" width="0">
15327 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
15328 <row topline="true" bottomline="true">
15329 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15346 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15355 <row topline="true">
15356 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15373 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15387 add floating point numbers
15391 <row topline="true">
15392 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15409 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15423 subtract floating point numbers
15427 <row topline="true">
15428 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15445 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15459 divide floating point numbers
15463 <row topline="true">
15464 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15481 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15495 multiply floating point numbers
15499 <row topline="true">
15500 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15517 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15531 convert floating point to unsigned char
15535 <row topline="true">
15536 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15553 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15567 convert floating point to signed char
15571 <row topline="true">
15572 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15589 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15603 convert floating point to unsigned int
15607 <row topline="true">
15608 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15625 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15639 convert floating point to signed int
15643 <row topline="true">
15644 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15670 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15684 convert floating point to unsigned long
15688 <row topline="true">
15689 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15706 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15720 convert floating point to signed long
15724 <row topline="true">
15725 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15742 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15756 convert unsigned char to floating point
15760 <row topline="true">
15761 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15778 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15792 convert char to floating point number
15796 <row topline="true">
15797 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15814 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15828 convert unsigned int to floating point
15832 <row topline="true">
15833 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15850 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15864 convert int to floating point numbers
15868 <row topline="true">
15869 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15886 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15900 convert unsigned long to floating point number
15904 <row topline="true" bottomline="true">
15905 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15922 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15936 convert long to floating point number
15948 \added_space_bottom bigskip
15949 These support routines are developed in ANSI-C so there is room for space
15950 and speed improvement
15956 These floating point routines (
15960 sinf(), cosf(), ...) for the mcs51 are implemented in assembler.
15965 Note if all these routines are used simultaneously the data space might
15967 For serious floating point usage the large model might be needed.
15968 Also notice that you don't have to call this routines directly.
15969 The compiler will use them automatically every time a floating point operation
15974 \begin_inset LatexCommand \index{Libraries}
15983 <pending: this is messy and incomplete - a little more information is in
15984 sdcc/doc/libdoc.txt
15989 Compiler support routines (_gptrget, _mulint etc.)
15992 Stdclib functions (puts, printf, strcat etc.)
15993 \layout Subsubsection
15999 \begin_inset LatexCommand \index{<stdio.h>}
16003 As usual on embedded systems you have to provide your own
16006 \begin_inset LatexCommand \index{getchar()}
16015 \begin_inset LatexCommand \index{putchar()}
16022 SDCC does not know whether the system connects to a serial line with or
16023 without handshake, LCD, keyboard or other device.
16037 You'll find examples for serial routines f.e.
16038 in sdcc/device/lib.
16044 \begin_inset LatexCommand \index{printf()}
16054 does not support float (except on ds390).
16055 To enable this recompile it with the option
16068 \begin_inset LatexCommand \index{USE\_FLOATS}
16074 on the command line.
16088 \begin_inset LatexCommand \index{-\/-model-large}
16094 for the mcs51 port, since this uses a lot of memory.
16097 If you're short on memory you might want to use
16100 \begin_inset LatexCommand \index{printf\_small()}
16115 For the mcs51 there additionally are assembly versions
16118 \begin_inset LatexCommand \index{printf\_tiny() (mcs51)}
16124 (subset of printf using less than 270 bytes) and
16127 \begin_inset LatexCommand \index{printf\_fast() (mcs51)}
16136 \begin_inset LatexCommand \index{printf\_fast\_f() (mcs51)}
16142 (floating-point aware version of printf_fast) which should fit the requirements
16143 of many embedded systems (printf_fast() can be customized by unsetting
16148 support long variables and field widths).
16149 \layout Subsubsection
16152 \begin_inset LatexCommand \index{malloc.h}
16159 As of SDCC 2.6.2 you no longer need to call an initialization routine before
16160 using dynamic memory allocation
16161 \begin_inset LatexCommand \index{dynamic memory allocation (malloc)}
16166 \begin_inset LatexCommand \index{heap (malloc)}
16170 space of 1024 bytes is provided for malloc to allocate memory from.
16171 If you need a different heap size you need to recompile _heap.c with the
16172 required size defined in HEAP_SIZE.
16173 It is recommended to make a copy of this file into your project directory
16174 and compile it there with:
16179 sdcc -c _heap.c -D HEAD_SIZE=2048
16183 And then link it with:
16188 sdcc main.rel _heap.rel
16193 Math functions (sinf, powf, sqrtf etc.)
16194 \layout Subsubsection
16199 See definitions in file <math.h>.
16206 \begin_inset LatexCommand \index{Libraries}
16210 included in SDCC should have a license at least as liberal as the GNU Lesser
16211 General Public License
16212 \begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
16223 license statements for the libraries are missing.
16224 sdcc/device/lib/ser_ir.c
16228 come with a GPL (as opposed to LGPL) License - this will not be liberal
16229 enough for many embedded programmers.
16232 If you have ported some library or want to share experience about some code
16234 falls into any of these categories Busses (I
16235 \begin_inset Formula $^{\textrm{2}}$
16238 C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
16239 cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
16240 Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list
16241 \begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}
16246 would certainly like to hear about it.
16248 \added_space_bottom bigskip
16249 Programmers coding for embedded systems are not especially famous for being
16250 enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
16251 e these references are very valuable.
16252 Let's help to create a climate where information is shared.
16258 MCS51 Memory Models
16259 \begin_inset LatexCommand \index{Memory model}
16264 \begin_inset LatexCommand \index{MCS51 memory model}
16269 \layout Subsubsection
16271 Small, Medium and Large
16274 SDCC allows three memory models for MCS51 code,
16283 Modules compiled with different memory models should
16287 be combined together or the results would be unpredictable.
16288 The library routines supplied with the compiler are compiled as small,
16290 The compiled library modules are contained in separate directories as small,
16291 medium and large so that you can link to the appropriate set.
16294 When the medium or large model is used all variables declared without a
16295 storage class will be allocated into the external ram, this includes all
16296 parameters and local variables (for non-reentrant
16297 \begin_inset LatexCommand \index{reentrant}
16302 When the small model is used variables without storage class are allocated
16303 in the internal ram.
16306 Judicious usage of the processor specific storage classes
16307 \begin_inset LatexCommand \index{Storage class}
16311 and the 'reentrant' function type will yield much more efficient code,
16312 than using the large model.
16313 Several optimizations are disabled when the program is compiled using the
16314 large model, it is therefore recommended that the small model be used unless
16315 absolutely required.
16316 \layout Subsubsection
16319 \begin_inset LatexCommand \label{sub:External-Stack}
16324 \begin_inset LatexCommand \index{stack}
16329 \begin_inset LatexCommand \index{External stack (mcs51)}
16336 The external stack (-
16347 \begin_inset LatexCommand \index{-\/-xstack}
16351 ) is located in pdata
16352 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
16356 memory (usually at the start of the external ram segment) and uses all
16357 unused space in pdata (max.
16369 -xstack option is used to compile the program, the parameters and local
16371 \begin_inset LatexCommand \index{local variables}
16375 of all reentrant functions are allocated in this area.
16376 This option is provided for programs with large stack space requirements.
16377 When used with the -
16388 \begin_inset LatexCommand \index{-\/-stack-auto}
16392 option, all parameters and local variables are allocated on the external
16393 stack (note: support libraries will need to be recompiled with the same
16395 There is a predefined target in the library makefile).
16398 The compiler outputs the higher order address byte of the external ram segment
16400 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
16405 \begin_inset LatexCommand \ref{sub:MCS51-variants}
16409 ), therefore when using the External Stack option, this port
16413 be used by the application program.
16417 \begin_inset LatexCommand \index{Memory model}
16422 \begin_inset LatexCommand \index{DS390 memory model}
16429 The only model supported is Flat 24
16430 \begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}
16435 This generates code for the 24 bit contiguous addressing mode of the Dallas
16437 In this mode, up to four meg of external RAM or code space can be directly
16439 See the data sheets at www.dalsemi.com for further information on this part.
16443 Note that the compiler does not generate any code to place the processor
16444 into 24 bitmode (although
16448 in the ds390 libraries will do that for you).
16454 \begin_inset LatexCommand \index{Tinibios (DS390)}
16458 , the boot loader or similar code must ensure that the processor is in 24
16459 bit contiguous addressing mode before calling the SDCC startup code.
16477 option, variables will by default be placed into the XDATA segment.
16482 Segments may be placed anywhere in the 4 meg address space using the usual
16494 Note that if any segments are located above 64K, the -r flag must be passed
16495 to the linker to generate the proper segment relocations, and the Intel
16496 HEX output format must be used.
16497 The -r flag can be passed to the linker by using the option
16501 on the SDCC command line.
16502 However, currently the linker can not handle code segments > 64k.
16506 \begin_inset LatexCommand \label{sec:Pragmas}
16511 \begin_inset LatexCommand \index{Pragmas}
16518 SDCC supports the following #pragma directives:
16526 \begin_inset LatexCommand \index{\#pragma save}
16530 - this will save most current options to the save/restore stack.
16531 See #pragma\SpecialChar ~
16540 \begin_inset LatexCommand \index{\#pragma restore}
16544 - will restore saved options from the last save.
16545 saves & restores can be nested.
16546 SDCC uses a save/restore stack: save pushes current options to the stack,
16547 restore pulls current options from the stack.
16548 See #pragma\SpecialChar ~
16559 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16564 \begin_inset LatexCommand \index{function prologue}
16568 function1[,function2[,function3...]] - The compiler by default uses a caller
16569 saves convention for register saving across function calls, however this
16570 can cause unnecessary register pushing & popping
16571 \begin_inset LatexCommand \index{push/pop}
16575 when calling small functions from larger functions.
16576 This option can be used to switch off the register saving convention for
16577 the function names specified.
16578 The compiler will not save registers when calling these functions, extra
16579 code need to be manually inserted at the entry & exit for these functions
16580 to save & restore the registers used by these functions, this can SUBSTANTIALLY
16581 reduce code & improve run time performance of the generated code.
16582 In the future the compiler (with inter procedural analysis) may be able
16583 to determine the appropriate scheme to use for each function call.
16594 -callee-saves command line option is used, the function names specified
16595 in #pragma\SpecialChar ~
16597 \begin_inset LatexCommand \index{\#pragma callee\_saves}
16601 is appended to the list of functions specified in the command line.
16609 \begin_inset LatexCommand \index{\#pragma exclude}
16613 none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables the generation
16614 of pairs of push/pop
16615 \begin_inset LatexCommand \index{push/pop}
16624 \begin_inset LatexCommand \index{interrupt}
16637 The directive should be placed immediately before the ISR function definition
16638 and it affects ALL ISR functions following it.
16639 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
16640 exclude\SpecialChar ~
16642 \begin_inset LatexCommand \index{\#pragma exclude}
16647 See also the related keyword _naked
16648 \begin_inset LatexCommand \index{\_naked}
16653 \begin_inset LatexCommand \index{\_\_naked}
16665 \begin_inset LatexCommand \index{\#pragma less\_pedantic}
16669 - the compiler will not warn you anymore for obvious mistakes, you'r on
16678 \begin_inset LatexCommand \index{\#pragma disable\_warning}
16682 - the compiler will not warn you anymore about warning number <nnnn>.
16690 \begin_inset LatexCommand \index{\#pragma nogcse}
16694 - will stop global common subexpression elimination.
16702 \begin_inset LatexCommand \index{\#pragma noinduction}
16706 - will stop loop induction optimizations.
16714 \begin_inset LatexCommand \index{\#pragma noinvariant}
16718 - will not do loop invariant optimizations.
16719 For more details see Loop Invariants in section
16720 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
16732 \begin_inset LatexCommand \index{\#pragma noiv}
16736 - Do not generate interrupt
16737 \begin_inset LatexCommand \index{interrupt}
16742 \begin_inset LatexCommand \index{interrupt vector table}
16746 entries for all ISR functions defined after the pragma.
16747 This is useful in cases where the interrupt vector table must be defined
16748 manually, or when there is a secondary, manually defined interrupt vector
16750 for the autovector feature of the Cypress EZ-USB FX2).
16751 More elegantly this can be achieved by obmitting the optional interrupt
16752 number after the interrupt keyword, see section
16753 \begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}
16766 \begin_inset LatexCommand \index{\#pragma nojtbound}
16770 - will not generate code for boundary value checking, when switch statements
16771 are turned into jump-tables (dangerous).
16772 For more details see section
16773 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
16785 \begin_inset LatexCommand \index{\#pragma noloopreverse}
16789 - Will not do loop reversal optimization
16797 \begin_inset LatexCommand \index{\#pragma nooverlay}
16801 - the compiler will not overlay the parameters and local variables of a
16810 \begin_inset LatexCommand \index{\#pragma stackauto}
16825 \begin_inset LatexCommand \index{-\/-stack-auto}
16830 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
16834 Parameters and Local Variables.
16842 \begin_inset LatexCommand \index{\#pragma opt\_code\_speed}
16846 - The compiler will optimize code generation towards fast code, possibly
16847 at the expense of code size.
16848 Currently this has little effect.
16856 \begin_inset LatexCommand \index{\#pragma opt\_code\_size}
16860 - The compiler will optimize code generation towards compact code, possibly
16861 at the expense of code speed.
16862 Currently this has little effect.
16870 \begin_inset LatexCommand \index{\#pragma opt\_code\_balanced}
16874 - The compiler will attempt to generate code that is both compact and fast,
16875 as long as meeting one goal is not a detriment to the other (this is the
16885 \begin_inset LatexCommand \index{\#pragma std\_sdcc89}
16889 - Generally follow the C89 standard, but allow SDCC features that conflict
16890 with the standard (default).
16898 \begin_inset LatexCommand \index{\#pragma std\_c89}
16902 - Follow the C89 standard and disable SDCC features that conflict with the
16911 \begin_inset LatexCommand \index{\#pragma std\_sdcc99}
16915 - Generally follow the C99 standard, but allow SDCC features that conflict
16916 with the standard (incomplete support).
16924 \begin_inset LatexCommand \index{\#pragma std\_c99}
16928 - Follow the C99 standard and disable SDCC features that conflict with the
16929 standard (incomplete support).
16937 \begin_inset LatexCommand \index{\#pragma codeseg}
16941 - Use this name (max.
16942 8 characters) for the code segment.
16961 \begin_inset LatexCommand \index{\#pragma constseg}
16965 - Use this name (max.
16966 8 characters) for the const segment.
16980 The preprocessor SDCPP
16981 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
16985 supports the following #pragma directives:
16990 pedantic_parse_number
16993 \begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}
16997 (+ | -) - Pedantic parse numbers so that situations like 0xfe-LO_B(3) are
16998 parsed properly and the macro LO_B(3) gets expanded.
17000 Below is an example on how to use this pragma.
17003 Note: this functionality is not in conformance with standard!
17008 #pragma pedantic_parse_number +
17009 \begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}
17017 #define LO_B(x) ((x) & 0xff)
17021 unsigned char foo(void)
17028 unsigned char c=0xfe-LO_B(3);
17047 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
17051 (+ | -) - switch _asm _endasm block preprocessing on / off.
17053 You use this prama to define multilines of assembly code.
17054 This will prevent the preprocessor from changing the formating required
17056 Below is an example on how to use this pragma.
17061 #pragma preproc_asm -
17062 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
17068 #define MYDELAY _asm
17073 nop ;my assembly comment...
17087 #pragma preproc_asm +
17122 \begin_inset LatexCommand \index{\#pragma sdcc\_hash}
17126 (+ | -) - Allow "naked" hash in macro definition, for example:
17130 #define DIR_LO(x) #(x & 0xff)
17135 Below is an example on how to use this pragma.
17140 #pragma preproc_asm +
17142 #pragma sdcc_hash +
17143 \begin_inset LatexCommand \index{\#pragma sdcc\_hash}
17158 mov R6_B3, #(x & 0xff)
17165 mov R7_B3, #((x >> 8) & 0xff)
17189 The pragma's are intended to be used to turn-on or off certain optimizations
17190 which might cause the compiler to generate extra stack / data space to
17191 store compiler generated temporary variables.
17192 This usually happens in large functions.
17193 Pragma directives should be used as shown in the following example, they
17194 are used to control options & optimizations for a given function; pragmas
17195 should be placed before and/or after a function, placing pragma's inside
17196 a function body could have unpredictable results.
17202 \begin_inset LatexCommand \index{\#pragma save}
17213 /* save the current settings */
17216 \begin_inset LatexCommand \index{\#pragma nogcse}
17225 /* turnoff global subexpression elimination */
17227 #pragma noinduction
17228 \begin_inset LatexCommand \index{\#pragma noinduction}
17232 /* turn off induction optimizations */
17255 \begin_inset LatexCommand \index{\#pragma restore}
17259 /* turn the optimizations back on */
17262 The compiler will generate a warning message when extra space is allocated.
17263 It is strongly recommended that the save and restore pragma's be used when
17264 changing options for a function.
17273 Defines Created by the Compiler
17276 The compiler creates the following #defines
17277 \begin_inset LatexCommand \index{\#defines}
17282 \begin_inset LatexCommand \index{Defines created by the compiler}
17292 \begin_inset Tabular
17293 <lyxtabular version="3" rows="11" columns="2">
17295 <column alignment="left" valignment="top" leftline="true" width="3in">
17296 <column alignment="left" valignment="top" leftline="true" rightline="true" width="3in">
17297 <row topline="true" bottomline="true">
17298 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17308 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17319 <row topline="true">
17320 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17326 \begin_inset LatexCommand \index{SDCC}
17333 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17339 Since version 2.5.6 the version number as an int (ex.
17344 <row topline="true">
17345 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17351 \begin_inset LatexCommand \index{SDCC\_mcs51}
17356 \begin_inset LatexCommand \index{SDCC\_ds390}
17361 \begin_inset LatexCommand \index{SDCC\_z80}
17368 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17373 depending on the model used (e.g.: -mds390)
17377 <row topline="true">
17378 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17384 \begin_inset LatexCommand \index{\_\_mcs51}
17389 \begin_inset LatexCommand \index{\_\_ds390}
17394 \begin_inset LatexCommand \index{\_\_hc08}
17399 \begin_inset LatexCommand \index{\_\_z80}
17406 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17411 depending on the model used (e.g.
17416 <row topline="true">
17417 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17423 \begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
17430 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17453 <row topline="true">
17454 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17460 \begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
17467 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17490 <row topline="true">
17491 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17497 \begin_inset LatexCommand \index{SDCC\_MODEL\_MEDIUM}
17504 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17527 <row topline="true">
17528 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17534 \begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
17541 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17564 <row topline="true">
17565 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17571 \begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
17578 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17601 <row topline="true">
17602 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17608 \begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
17615 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17628 <row topline="true" bottomline="true">
17629 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17635 \begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
17642 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17662 Notes on supported Processors
17666 \begin_inset LatexCommand \label{sub:MCS51-variants}
17671 \begin_inset LatexCommand \index{MCS51 variants}
17678 MCS51 processors are available from many vendors and come in many different
17680 While they might differ considerably in respect to Special Function Registers
17681 the core MCS51 is usually not modified or is kept compatible.
17685 pdata access by SFR
17688 With the upcome of devices with internal xdata and flash memory devices
17690 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
17694 as dedicated I/O port is becoming more popular.
17695 Switching the high byte for pdata
17696 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
17700 access which was formerly done by port P2 is then achieved by a Special
17702 \begin_inset LatexCommand \index{sfr}
17707 In well-established MCS51 tradition the address of this
17711 is where the chip designers decided to put it.
17712 Needless to say that they didn't agree on a common name either.
17713 So that the startup code can correctly initialize xdata variables, you
17714 should define an sfr with the name _XPAGE
17717 \begin_inset LatexCommand \index{\_XPAGE (mcs51)}
17723 at the appropriate location if the default, port P2, is not used for this.
17729 __sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family */
17734 __sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17739 __sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips */
17742 For more exotic implementations further customizations may be needed.
17744 \begin_inset LatexCommand \ref{sub:Startup-Code}
17748 for other possibilities.
17751 Other Features available by SFR
17753 \added_space_bottom bigskip
17754 Some MCS51 variants offer features like Double DPTR
17755 \begin_inset LatexCommand \index{DPTR}
17759 , multiple DPTR, decrementing DPTR, 16x16 Multiply.
17760 These are currently not used for the MCS51 port.
17761 If you absolutely need them you can fall back to inline assembly or submit
17767 \added_space_bottom bigskip
17769 \begin_inset LatexCommand \index{DS80C400}
17774 \begin_inset LatexCommand \index{DS400}
17778 microcontroller has a rich set of peripherals.
17779 In its built-in ROM library it includes functions to access some of the
17780 features, among them is a TCP stack with IP4 and IP6 support.
17781 Library headers (currently in beta status) and other files are provided
17785 \begin_inset LatexCommand \url{ftp://ftp.dalsemi.com/pub/tini/ds80c400/c_libraries/sdcc/index.html}
17793 The Z80 and gbz80 port
17796 SDCC can target both the Zilog Z80
17797 \begin_inset LatexCommand \index{Z80}
17801 and the Nintendo Gameboy's Z80-like gbz80
17802 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
17807 The Z80 port is passed through the same
17810 \begin_inset LatexCommand \index{Regression test}
17817 \begin_inset LatexCommand \ref{sec:Quality-control}
17821 ) as the MCS51 and DS390 ports, so floating point support, support for long
17822 variables and bitfield support is fine.
17823 See mailing lists and forums about interrupt routines.
17825 \added_space_bottom bigskip
17826 As always, the code is the authoritative reference - see z80/ralloc.c and
17829 \begin_inset LatexCommand \index{Z80!stack}
17833 frame is similar to that generated by the IAR Z80 compiler.
17834 IX is used as the base pointer, HL and IY are used as a temporary registers,
17835 and BC and DE are available for holding variables.
17837 \begin_inset LatexCommand \index{Z80!return value}
17841 for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
17843 The gbz80 port use the same set of registers for the return values, but
17844 in a different order of significance: E (one byte), DE (two bytes), or
17851 The port to the Freescale/Motorola HC08
17852 \begin_inset LatexCommand \index{HC08}
17856 family has been added in October 2003, and is still undergoing some basic
17858 The code generator is complete, but the register allocation is still quite
17860 Some of the SDCC's standard C library functions have embedded non-HC08
17861 inline assembly and so are not yet usable.
17863 \added_space_bottom bigskip
17864 The HC08 port passes the regression test suite (see section
17865 \begin_inset LatexCommand \ref{sec:Quality-control}
17876 \begin_inset LatexCommand \index{PIC14}
17880 port still requires a major effort from the development community.
17881 However it can work for simple code.
17882 It passes its (smaller set of) regression tests
17883 \begin_inset LatexCommand \index{Regression test (PIC14)}
17889 sdcc/src/regression
17894 C code and 14bit PIC code page
17895 \begin_inset LatexCommand \index{code page (pic14)}
17900 \begin_inset LatexCommand \index{RAM bank (pic14)}
17907 The linker organizes allocation for the code page and RAM banks.
17908 It does not have intimate knowledge of the code flow.
17909 It will put all the code section of a single asm file into a single code
17911 In order to make use of multiple code pages, separate asm files must be
17913 The compiler treats all functions of a single C file as being in the same
17914 code page unless it is non static.
17918 To get the best follow these guide lines:
17921 Make local functions static, as non static functions require code page selection
17925 For devices that have multiple code pages it is more efficient to use the
17926 same number of files as pages, i.e.
17927 for the 16F877 use 4 separate files and i.e.
17928 for the 16F874 use 2 separate files.
17929 This way the linker can put the code for each file into different code
17930 pages and there's less page selection overhead.
17933 And as for any 8 bit micro (especially for PIC 14 as they have a very simple
17934 instruction set), use 'unsigned char' whereever possible instead of 'int'.
17937 Creating a device include file
17940 For generating a device include file
17941 \begin_inset LatexCommand \index{PIC14!Header files}
17945 use the support perl script inc2h.pl kept in directory support/script.
17951 For the interrupt function, use the keyword '__interrupt'
17952 \begin_inset LatexCommand \index{PIC14!interrupt}
17956 with level number of 0 (PIC14 only has 1 interrupt so this number is only
17957 there to avoid a syntax error - it ought to be fixed).
17963 void Intr(void) __interrupt 0
17969 T0IF = 0; /* Clear timer interrupt */
17974 Linking and assembling
17977 For assembling you can use either GPUTILS'
17978 \begin_inset LatexCommand \index{gputils (pic tools)}
17982 gpasm.exe or MPLAB's mpasmwin.exe.
17983 GPUTILS is available from
17984 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
17989 For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
17990 If you use MPLAB and an interrupt function then the linker script file
17991 vectors section will need to be enlarged to link with mplink.
18014 sdcc -S -V -mpic14 -p16F877 $<
18028 $(PRJ).hex: $(OBJS)
18038 gplink -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS) libsdcc.lib
18060 sdcc -S -V -mpic14 -p16F877 $<
18070 mpasmwin /q /o $*.asm
18074 $(PRJ).hex: $(OBJS)
18084 mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS) libsdcc.lib
18087 Please note that indentations within a
18091 have to be done with a tabulator character.
18094 Command-line options
18097 Besides the switches common to all SDCC backends, the PIC14 port accepts
18098 the following options (for an updated list see sdcc -
18110 \labelwidthstring 00.00.0000
18123 \begin_inset LatexCommand \index{PIC14!Options!-\/-debug-extra}
18127 emit debug info in assembly output
18129 \labelwidthstring 00.00.0000
18142 \begin_inset LatexCommand \index{PIC14!Options!-\/-no-pcode-opt}
18146 disable (slightly faulty) optimization on pCode
18148 \labelwidthstring 00.00.0000
18161 \begin_inset LatexCommand \index{PIC14!Options!-\/-stack-loc}
18165 sets the lowest address of the argument passing stack (defaults to a suitably
18166 large shared databank to reduce BANKSEL overhead)
18168 \labelwidthstring 00.00.0000
18181 \begin_inset LatexCommand \index{PIC14!Options!-\/-stack-size}
18185 sets the size if the argument passing stack (default: 16, minimum: 4)
18189 \layout Subsubsection
18191 error: missing definition for symbol
18192 \begin_inset Quotes sld
18196 \begin_inset Quotes srd
18202 The PIC14 port uses library routines to provide more complex operations
18203 like multiplication, division/modulus and (generic) pointer dereferencing.
18204 In order to add these routines to your project, you must link with PIC14's
18210 For single source file projects this is done automatically, more complex
18215 to the linker's arguments.
18216 Make sure you also add an include path for the library (using the -I switch
18218 \layout Subsubsection
18220 Processor mismatch in file
18221 \begin_inset Quotes sld
18225 \begin_inset Quotes srd
18231 This warning can usually be ignored due to the very good compatibility amongst
18233 \begin_inset LatexCommand \index{PIC14}
18240 You might also consider recompiling the library for your specific device
18241 by changing the ARCH=p16f877 (default target) entry in
18243 device/lib/pic/Makefile.in
18247 device/lib/pic/Makefile
18249 to reflect your device.
18250 This might even improve performance for smaller devices as unneccesary
18251 BANKSELs migth be removed.
18255 \layout Subsubsection
18260 Currently, data can only be initialized if it resides in the source file
18266 Data in other source files will silently
18274 \begin_inset Marginal
18289 \begin_inset LatexCommand \index{PIC16}
18297 \begin_inset LatexCommand \index{PIC16}
18301 port is the portion of SDCC that is responsible to produce code for the
18303 \begin_inset LatexCommand \index{Microchip}
18307 (TM) microcontrollers with 16 bit core.
18308 Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
18309 Currently supported devices are:
18313 \begin_inset Tabular
18314 <lyxtabular version="3" rows="4" columns="6">
18316 <column alignment="center" valignment="top" leftline="true" width="0">
18317 <column alignment="center" valignment="top" leftline="true" width="0">
18318 <column alignment="center" valignment="top" leftline="true" width="0">
18319 <column alignment="center" valignment="top" leftline="true" width="0">
18320 <column alignment="center" valignment="top" leftline="true" width="0">
18321 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18322 <row topline="true">
18323 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18331 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18339 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18347 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18355 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18363 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18372 <row topline="true">
18373 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18381 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18389 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18397 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18405 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18413 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18422 <row topline="true">
18423 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18431 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18439 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18447 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18455 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18463 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18472 <row topline="true" bottomline="true">
18473 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18481 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18489 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18497 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18504 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18511 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18529 PIC16 port supports the standard command line arguments as supposed, with
18530 the exception of certain cases that will be mentioned in the following
18533 \labelwidthstring 00.00.0000
18546 \begin_inset LatexCommand \index{PIC16!Options!-\/-callee-saves}
18562 \labelwidthstring 00.00.0000
18575 \begin_inset LatexCommand \index{PIC16!Options!-\/-all-callee-saves}
18579 All function arguments are passed on stack by default.
18582 There is no need to specify this in the command line.
18584 \labelwidthstring 00.00.0000
18596 -fommit-frame-pointer
18597 \begin_inset LatexCommand \index{PIC16!Options!-\/-fommit-frame-pointer}
18601 Frame pointer will be omitted when the function uses no local variables.
18604 Port Specific Options
18605 \begin_inset LatexCommand \index{Options PIC16}
18612 The port specific options appear after the global options in the sdcc --help
18614 \layout Subsubsection
18619 General options enable certain port features and optimizations.
18621 \labelwidthstring 00.00.0000
18633 -pstack-model=[model] Used in conjuction with the command above.
18634 Defines the stack model to be used, valid stack models are :
18637 \labelwidthstring 00.00.0000
18643 Selects small stack model.
18644 8 bit stack and frame pointers.
18645 Supports 256 bytes stack size.
18647 \labelwidthstring 00.00.0000
18653 Selects large stack model.
18654 16 bit stack and frame pointers.
18655 Supports 65536 bytes stack size.
18658 \labelwidthstring 00.00.0000
18670 -preplace-udata-with=[kword] Replaces the default udata keyword for allocating
18671 unitialized data variables with [kword].
18672 Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
18674 \labelwidthstring 00.00.0000
18686 -ivt-loc <nnnn> positions the Interrupt Vector Table at location <nnnn>.
18687 Useful for bootloaders.
18689 \labelwidthstring 00.00.0000
18701 -asm= sets the full path and name of an external assembler to call.
18703 \labelwidthstring 00.00.0000
18715 -link= sets the full path and name of an external linker to call.
18717 \labelwidthstring 00.00.0000
18730 \begin_inset LatexCommand \index{PIC16!MPLAB}
18734 compatibility option.
18735 Currently only suppresses special gpasm directives.
18736 \layout Subsubsection
18738 Optimization Options
18740 \labelwidthstring 00.00.0000
18752 -optimize-goto Try to use (conditional) BRA instead of GOTO
18754 \labelwidthstring 00.00.0000
18766 -optimize-cmp Try to optimize some compares.
18768 \labelwidthstring 00.00.0000
18780 -optimize-df Analyze the dataflow of the generated code and improve it.
18782 \labelwidthstring 00.00.0000
18794 -obanksel=nn Set optimization level for inserting BANKSELs.
18799 \labelwidthstring 00.00.0000
18803 \labelwidthstring 00.00.0000
18805 1 checks previous used register and if it is the same then does not emit
18806 BANKSEL, accounts only for labels.
18808 \labelwidthstring 00.00.0000
18810 2 tries to check the location of (even different) symbols and removes BANKSELs
18811 if they are in the same bank.
18816 Important: There might be problems if the linker script has data sections
18817 across bank borders!
18819 \layout Subsubsection
18823 \labelwidthstring 00.00.0000
18835 -nodefaultlibs do not link default libraries when linking
18837 \labelwidthstring 00.00.0000
18849 -no-crt Don't link the default run-time modules
18851 \labelwidthstring 00.00.0000
18863 -use-crt= Use a custom run-time module instead of the defaults.
18864 \layout Subsubsection
18869 Debugging options enable extra debugging information in the output files.
18871 \labelwidthstring 00.00.0000
18883 -debug-xtra Similar to -
18894 \begin_inset LatexCommand \index{-\/-debug}
18898 , but dumps more information.
18900 \labelwidthstring 00.00.0000
18912 -debug-ralloc Force register allocator to dump <source>.d file with debugging
18914 <source> is the name of the file compiled.
18916 \labelwidthstring 00.00.0000
18928 -pcode-verbose Enable pcode debugging information in translation.
18930 \labelwidthstring 00.00.0000
18942 -denable-peeps Force the usage of peepholes.
18945 \labelwidthstring 00.00.0000
18957 -gstack Trace push/pops for stack pointer overflow
18959 \labelwidthstring 00.00.0000
18971 -call-tree dump call tree in .calltree file
18974 Enviromental Variables
18977 There is a number of enviromental variables that can be used when running
18978 SDCC to enable certain optimizations or force a specific program behaviour.
18979 these variables are primarily for debugging purposes so they can be enabled/dis
18983 Currently there is only two such variables available:
18985 \labelwidthstring 00.00.0000
18987 OPTIMIZE_BITFIELD_POINTER_GET when this variable exists reading of structure
18988 bitfields is optimized by directly loading FSR0 with the address of the
18989 bitfield structure.
18990 Normally SDCC will cast the bitfield structure to a bitfield pointer and
18992 This step saves data ram and code space for functions that perform heavy
18995 80 bytes of code space are saved when compiling malloc.c with this option).
18998 \labelwidthstring 00.00.0000
19000 NO_REG_OPT do not perform pCode registers optimization.
19001 This should be used for debugging purposes.
19002 In some where bugs in the pcode optimizer are found, users can benefit
19003 from temporarily disabling the optimizer until the bug is fixed.
19006 Preprocessor Macros
19010 \begin_inset LatexCommand \index{PIC16}
19014 port defines the following preprocessor macros while translating a source.
19018 \begin_inset Tabular
19019 <lyxtabular version="3" rows="6" columns="2">
19021 <column alignment="center" valignment="top" leftline="true" width="0">
19022 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19023 <row topline="true" bottomline="true">
19024 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19032 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19041 <row topline="true">
19042 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19050 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19055 Port identification
19059 <row topline="true">
19060 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19078 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19083 Port identification (same as above)
19087 <row topline="true">
19088 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19096 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19101 MCU Identification.
19106 is the microcontrol identification number, i.e.
19111 <row topline="true">
19112 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19130 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19135 MCU Identification (same as above)
19139 <row topline="true" bottomline="true">
19140 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19148 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19153 nnn = SMALL or LARGE respectively according to the stack model used
19164 In addition the following macros are defined when calling assembler:
19168 \begin_inset Tabular
19169 <lyxtabular version="3" rows="4" columns="2">
19171 <column alignment="center" valignment="top" leftline="true" width="0">
19172 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19173 <row topline="true" bottomline="true">
19174 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19182 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19191 <row topline="true">
19192 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19200 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19205 MCU Identification.
19210 is the microcontrol identification number, i.e.
19215 <row topline="true">
19216 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19224 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19229 nnn = SMALL or LARGE respectively according to the memory model used for
19234 <row topline="true" bottomline="true">
19235 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19243 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19248 nnn = SMALL or LARGE respectively according to the stack model used
19263 \begin_inset LatexCommand \index{PIC16}
19267 port uses the following directories for searching header files and libraries.
19271 \begin_inset Tabular
19272 <lyxtabular version="3" rows="3" columns="4">
19274 <column alignment="center" valignment="top" leftline="true" width="0">
19275 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19276 <column alignment="center" valignment="top" width="0">
19277 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19278 <row topline="true" bottomline="true">
19279 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19287 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19295 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19303 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19312 <row topline="true">
19313 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19318 PREFIX/sdcc/include/pic16
19321 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19326 PIC16 specific headers
19329 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19337 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19346 <row topline="true" bottomline="true">
19347 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19352 PREFIX/sdcc/lib/pic16
19355 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19360 PIC16 specific libraries
19363 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19371 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19388 \begin_inset LatexCommand \label{sub:PIC16_Pragmas}
19396 \begin_inset LatexCommand \index{PIC16}
19400 port currently supports the following pragmas:
19402 \labelwidthstring 00.00.0000
19405 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}
19410 \begin_inset LatexCommand \index{PIC16!stack}
19414 forces the code generator to initialize the stack & frame pointers at a
19416 This is an adhoc solution for cases where no STACK directive is available
19417 in the linker script or gplink is not instructed to create a stack section.
19419 The stack pragma should be used only once in a project.
19420 Multiple pragmas may result in indeterminate behaviour of the program.
19426 The old format (ie.
19427 #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
19428 cross page boundaries (or even exceed the available data RAM) and crash
19430 Make sure that stack does not cross page boundaries when using the SMALL
19436 The format is as follows:
19439 #pragma stack bottom_address [stack_size]
19446 is the lower bound of the stack section.
19447 The stack pointer initially will point at address (bottom_address+stack_size-1).
19455 /* initializes stack of 100 bytes at RAM address 0x200 */
19458 #pragma stack 0x200 100
19461 If the stack_size field is omitted then a stack is created with the default
19463 This size might be enough for most programs, but its not enough for operations
19464 with deep function nesting or excessive stack usage.
19466 \labelwidthstring 00.00.0000
19469 \begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}
19473 place a function symbol at static FLASH address
19481 /* place function test_func at 0x4000 */
19484 #pragma code test_func 0x4000
19488 \labelwidthstring 00.00.0000
19490 library instructs the linker to use a library module.
19495 #pragma library module_name
19502 can be any library or object file (including its path).
19503 Note that there are four reserved keywords which have special meaning.
19508 \begin_inset Tabular
19509 <lyxtabular version="3" rows="6" columns="3">
19511 <column alignment="center" valignment="top" leftline="true" width="0">
19512 <column alignment="block" valignment="top" leftline="true" width="20page%">
19513 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
19514 <row topline="true" bottomline="true">
19515 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19523 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19531 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19540 <row topline="true">
19541 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19551 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19556 ignore all library pragmas
19559 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19570 <row topline="true">
19571 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19581 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19589 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19602 <row topline="true">
19603 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19613 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19618 link the Math libarary
19621 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19634 <row topline="true">
19635 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19645 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19650 link the I/O library
19653 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19666 <row topline="true" bottomline="true">
19667 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19677 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19682 link the debug library
19685 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19704 * is the device number, i.e.
19705 452 for PIC18F452 MCU.
19708 This feature allows for linking with specific libraries withoug having to
19709 explicit name them in the command line.
19714 keyword will reject all modules specified by the library pragma.
19716 \labelwidthstring 00.00.0000
19718 udata pragma udata instructs the compiler to emit code so that linker will
19719 place a variable at a specific memory bank
19727 /* places variable foo at bank2 */
19730 #pragma udata bank2 foo
19736 In order for this pragma to work extra SECTION directives should be added
19737 in the .lkr script.
19738 In the following example a sample .lkr file is shown:
19743 // Sample linker script for the PIC18F452 processor
19749 CODEPAGE NAME=vectors START=0x0 END=0x29 PROTECTED
19752 CODEPAGE NAME=page START=0x2A END=0x7FFF
19755 CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
19758 CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
19761 CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
19764 CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED
19767 ACCESSBANK NAME=accessram START=0x0 END=0x7F
19772 DATABANK NAME=gpr0 START=0x80 END=0xFF
19775 DATABANK NAME=gpr1 START=0x100 END=0x1FF
19778 DATABANK NAME=gpr2 START=0x200 END=0x2FF
19781 DATABANK NAME=gpr3 START=0x300 END=0x3FF
19784 DATABANK NAME=gpr4 START=0x400 END=0x4FF
19787 DATABANK NAME=gpr5 START=0x500 END=0x5FF
19790 ACCESSBANK NAME=accesssfr START=0xF80 END=0xFFF PROTECTED
19795 SECTION NAME=CONFIG ROM=config
19800 SECTION NAME=bank0 RAM=gpr0 # these SECTION directives
19803 SECTION NAME=bank1 RAM=gpr1 # should be added to link
19806 SECTION NAME=bank2 RAM=gpr2 # section name 'bank?' with
19809 SECTION NAME=bank3 RAM=gpr3 # a specific DATABANK name
19812 SECTION NAME=bank4 RAM=gpr4
19815 SECTION NAME=bank5 RAM=gpr5
19818 The linker will recognise the section name set in the pragma statement and
19819 will position the variable at the memory bank set with the RAM field at
19820 the SECTION line in the linker script file.
19824 \begin_inset LatexCommand \label{sub:PIC16_Header-Files}
19831 There is one main header file
19832 \begin_inset LatexCommand \index{PIC16!Header files}
19836 that can be included to the source files using the pic16
19837 \begin_inset LatexCommand \index{PIC16}
19847 This header file contains the definitions for the processor special registers,
19848 so it is necessary if the source accesses them.
19849 It can be included by adding the following line in the beginning of the
19853 #include <pic18fregs.h>
19856 The specific microcontroller is selected within the pic18fregs.h automatically,
19857 so the same source can be used with a variety of devices.
19864 \begin_inset LatexCommand \index{PIC16!Libraries}
19869 \begin_inset LatexCommand \index{PIC16}
19873 port depends on are the microcontroller device libraries which contain
19874 the symbol definitions for the microcontroller special function registers.
19875 These libraries have the format pic18fxxxx.lib, where
19879 is the microcontroller identification number.
19880 The specific library is selected automatically by the compiler at link
19881 stage according to the selected device.
19884 Libraries are created with gplib which is part of the gputils package
19885 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
19890 \layout Subsubsection*
19892 Building the libraries
19895 Before using SDCC/pic16 there are some libraries that need to be compiled.
19896 This process is not done automatically by SDCC since not all users use
19897 SDCC for pic16 projects.
19898 So each user should compile the libraries separately.
19901 The steps to compile the pic16 libraries under Linux are:
19904 cd device/lib/pic16
19919 su -c 'make install' # install the libraries, you need the root password
19922 If you need to install the headers too, do:
19928 su -c 'make install' # install the headers, you need the root password
19931 There exist a special target to build the I/O libraries.
19932 This target is not automatically build because it will build the I/O library
19938 This way building will take quite a lot of time.
19939 Users are advised to edit the
19941 device/lib/pic16/pics.build
19943 file and then execute:
19952 The following memory models are supported by the PIC16 port:
19961 Memory model affects the default size of pointers within the source.
19962 The sizes are shown in the next table:
19966 \begin_inset Tabular
19967 <lyxtabular version="3" rows="3" columns="3">
19969 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19970 <column alignment="center" valignment="top" leftline="true" width="0">
19971 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19972 <row topline="true" bottomline="true">
19973 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19978 Pointer sizes according to memory model
19981 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19989 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19998 <row topline="true" bottomline="true">
19999 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20007 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20015 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20024 <row topline="true" bottomline="true">
20025 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20033 <cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
20041 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20057 It is advisable that all sources within a project are compiled with the
20059 If one wants to override the default memory model, this can be done by
20060 declaring a pointer as
20069 Far selects large memory model's pointers, while near selects small memory
20073 The standard device libraries (see
20074 \begin_inset LatexCommand \ref{sub:PIC16_Header-Files}
20078 ) contain no reference to pointers, so they can be used with both memory
20086 \begin_inset LatexCommand \index{PIC16!stack}
20090 implementation for the PIC16 port uses two indirect registers, FSR1 and
20093 \labelwidthstring 00.00.0000
20095 FSR1 is assigned as stack pointer
20097 \labelwidthstring 00.00.0000
20099 FSR2 is assigned as frame pointer
20102 The following stack models are supported by the PIC16 port
20123 model means that only the FSRxL byte is used to access stack and frame,
20130 uses both FSRxL and FSRxH registers.
20131 The following table shows the stack/frame pointers sizes according to stack
20132 model and the maximum space they can address:
20136 \begin_inset Tabular
20137 <lyxtabular version="3" rows="3" columns="3">
20139 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20140 <column alignment="center" valignment="top" leftline="true" width="0">
20141 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20142 <row topline="true" bottomline="true">
20143 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20148 Stack & Frame pointer sizes according to stack model
20151 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20159 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20168 <row topline="true">
20169 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20177 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20185 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20194 <row topline="true" bottomline="true">
20195 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20203 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20211 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20231 stack model is currently not working properly throughout the code generator.
20232 So its use is not advised.
20233 Also there are some other points that need special care:
20238 Do not create stack sections with size more than one physical bank (that
20242 Stack sections should no cross physical bank limits (i.e.
20243 #pragma stack 0x50 0x100)
20246 These limitations are caused by the fact that only FSRxL is modified when
20247 using SMALL stack model, so no more than 256 bytes of stack can be used.
20248 This problem will disappear after LARGE model is fully implemented.
20254 In addition to the standard SDCC function keywords, PIC16
20255 \begin_inset LatexCommand \index{PIC16}
20259 port makes available two more:
20261 \labelwidthstring 00.00.0000
20264 \begin_inset LatexCommand \index{PIC16!wparam}
20268 Use the WREG to pass one byte of the first function argument.
20269 This improves speed but you may not use this for functions with arguments
20270 that are called via function pointers, otherwise the first byte of the
20271 first parameter will get lost.
20275 void func_wparam(int a) wparam
20281 /* WREG hold the lower part of a */
20284 /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
20293 \labelwidthstring 00.00.0000
20296 \begin_inset LatexCommand \index{PIC16!shadowregs}
20300 When entering/exiting an ISR, it is possible to take advantage of the PIC18F
20301 hardware shadow registers which hold the values of WREG, STATUS and BSR
20303 This can be done by adding the keyword
20311 keyword in the function's header.
20314 void isr_shadow(void) shadowregs interrupt 1
20330 instructs the code generator not to store/restore WREG, STATUS, BSR when
20331 entering/exiting the ISR.
20334 Function return values
20337 Return values from functions are placed to the appropriate registers following
20338 a modified Microchip policy optimized for SDCC.
20339 The following table shows these registers:
20343 \begin_inset Tabular
20344 <lyxtabular version="3" rows="6" columns="2">
20346 <column alignment="center" valignment="top" leftline="true" width="0">
20347 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20348 <row topline="true" bottomline="true">
20349 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20357 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20362 destination register
20366 <row topline="true">
20367 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20375 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20384 <row topline="true">
20385 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20393 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20402 <row topline="true">
20403 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20411 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20420 <row topline="true">
20421 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20429 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20434 FSR0L:PRODH:PRODL:WREG
20438 <row topline="true" bottomline="true">
20439 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20447 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20452 on stack, FSR0 points to the beginning
20467 \begin_inset LatexCommand \index{PIC16!interrupt}
20471 service routine (ISR) is declared using the
20478 void isr(void) interrupt
20496 is the interrupt number, which for PIC18F devices can be:
20500 \begin_inset Tabular
20501 <lyxtabular version="3" rows="4" columns="3">
20503 <column alignment="center" valignment="top" leftline="true" width="0">
20504 <column alignment="center" valignment="top" leftline="true" width="0">
20505 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20506 <row topline="true" bottomline="true">
20507 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20517 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20525 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20530 Interrupt Vector Address
20534 <row topline="true">
20535 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20543 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20551 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20560 <row topline="true">
20561 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20578 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20592 HIGH priority interrupts
20595 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20604 <row topline="true" bottomline="true">
20605 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20613 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20618 LOW priority interrupts
20621 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20637 When generating assembly code for ISR the code generator places a
20643 Interrupt Vector Address
20645 which points at the genetated ISR.
20646 This single GOTO instruction is part of an automatically generated
20648 interrupt entry point
20651 The actuall ISR code is placed as normally would in the code space.
20652 Upon interrupt request, the GOTO instruction is executed which jumps to
20654 When declaring interrupt functions as _naked this GOTO instruction is
20659 The whole interrupt functions is therefore placed at the Interrupt Vector
20660 Address of the specific interrupt.
20661 This is not a problem for the LOW priority interrupts, but it is a problem
20662 for the RESET and the HIGH priority interrupts because code may be written
20663 at the next interrupt´s vector address and cause undeterminate program
20664 behaviour if that interrupt is raised.
20670 This is not a problem when
20673 this is a HIGH interrupt ISR and LOW interrupts are
20680 when the ISR is small enough not to reach the next interrupt´s vector address.
20690 is possible to be omitted.
20691 This way a function is generated similar to an ISR, but it is not assigned
20695 When entering an interrupt, currently the PIC16
20696 \begin_inset LatexCommand \index{PIC16}
20700 port automatically saves the following registers:
20712 PROD (PRODL and PRODH)
20715 FSR0 (FSR0L and FSR0H)
20718 These registers are restored upon return from the interrupt routine.
20724 NOTE that when the _naked attribute is specified for an interrupt routine,
20725 then NO registers are stored or restored.
20734 Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
20735 There are 3 types of generic pointers currently implemented data, code
20736 and eeprom pointers.
20737 They are differentiated by the value of the 7th and 6th bits of the upper
20742 \begin_inset Tabular
20743 <lyxtabular version="3" rows="5" columns="5">
20745 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20746 <column alignment="center" valignment="top" width="0">
20747 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
20748 <column alignment="center" valignment="top" width="0">
20749 <column alignment="left" valignment="top" rightline="true" width="0">
20750 <row topline="true" bottomline="true">
20751 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20759 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20767 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20775 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20780 rest of the pointer
20783 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20792 <row topline="true" bottomline="true">
20793 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20801 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20809 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20817 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20826 uuuuuu uuuuxxxx xxxxxxxx
20829 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20834 a 12-bit data pointer in data RAM memory
20838 <row bottomline="true">
20839 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20847 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20855 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20863 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20872 uxxxxx xxxxxxxx xxxxxxxx
20875 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20880 a 21-bit code pointer in FLASH memory
20884 <row bottomline="true">
20885 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20893 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20901 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20909 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20918 uuuuuu uuuuuuxx xxxxxxxx
20921 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20926 a 10-bit eeprom pointer in EEPROM memory
20930 <row bottomline="true">
20931 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20939 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
20947 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20955 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20964 xxxxxx xxxxxxxx xxxxxxxx
20967 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
20972 unimplemented pointer type
20983 Generic pointer are read and written with a set of library functions which
20984 read/write 1, 2, 3, 4 bytes.
20988 \layout Subsubsection
20990 Standard I/O Streams
20997 the type FILE is defined as:
21000 typedef char * FILE;
21003 This type is the stream type implemented I/O in the PIC18F devices.
21004 Also the standard input and output streams are declared in stdio.h:
21007 extern FILE * stdin;
21010 extern FILE * stdout;
21013 The FILE type is actually a generic pointer which defines one more type
21014 of generic pointers, the
21019 This new type has the format:
21023 \begin_inset Tabular
21024 <lyxtabular version="3" rows="2" columns="7">
21026 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21027 <column alignment="center" valignment="top" width="0">
21028 <column alignment="center" valignment="top" leftline="true" width="0">
21029 <column alignment="center" valignment="top" leftline="true" width="0">
21030 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21031 <column alignment="center" valignment="top" width="0">
21032 <column alignment="left" valignment="top" rightline="true" width="0">
21033 <row topline="true" bottomline="true">
21034 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21042 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21050 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21058 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21066 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21074 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21079 rest of the pointer
21082 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21091 <row topline="true" bottomline="true">
21092 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21100 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21108 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21116 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21124 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21132 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21144 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21149 upper byte high nubble is 0x2n, the rest are zeroes
21160 Currently implemented there are 3 types of streams defined:
21164 \begin_inset Tabular
21165 <lyxtabular version="3" rows="4" columns="4">
21167 <column alignment="center" valignment="top" leftline="true" width="0">
21168 <column alignment="center" valignment="top" leftline="true" width="0">
21169 <column alignment="center" valignment="top" leftline="true" width="0">
21170 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21171 <row topline="true" bottomline="true">
21172 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21180 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21188 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21196 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21205 <row topline="true">
21206 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21214 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21224 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21232 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21237 Writes/Reads characters via the USART peripheral
21241 <row topline="true">
21242 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21250 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21260 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21268 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21273 Writes/Reads characters via the MSSP peripheral
21277 <row topline="true" bottomline="true">
21278 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21286 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21296 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21304 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21309 Writes/Reads characters via used defined functions
21320 The stream identifiers are declared as macros in the stdio.h header.
21323 In the libc library there exist the functions that are used to write to
21324 each of the above streams.
21327 \labelwidthstring 00.00.0000
21339 _stream_usart_putchar writes a character at the USART stream
21341 \labelwidthstring 00.00.0000
21353 _stream_mssp_putchar writes a character at the MSSP stream
21355 \labelwidthstring 00.00.0000
21357 putchar dummy function.
21358 This writes a character to a user specified manner.
21361 In order to increase performance
21365 is declared in stdio.h as having its parameter in WREG (it has the wparam
21367 In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
21368 in a user-friendly way.
21373 is the name of the variable that holds the character to print.
21374 An example follows:
21377 #include <pic18fregs.h>
21389 PORTA = c; /* dump character c to PORTA */
21402 stdout = STREAM_USER; /* this is not necessary, since stdout points
21405 * by default to STREAM_USER */
21408 printf (¨This is a printf test
21416 \layout Subsubsection
21421 PIC16 contains an implementation of the printf-family of functions.
21422 There exist the following functions:
21425 extern unsigned int sprintf(char *buf, char *fmt, ...);
21428 extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
21433 extern unsigned int printf(char *fmt, ...);
21436 extern unsigned int vprintf(char *fmt, va_lista ap);
21441 extern unsigned int fprintf(FILE *fp, char *fmt, ...);
21444 extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
21447 For sprintf and vsprintf
21451 should normally be a data pointer where the resulting string will be placed.
21452 No range checking is done so the user should allocate the necessery buffer.
21453 For fprintf and vfprintf
21457 should be a stream pointer (i.e.
21458 stdout, STREAM_MSSP, etc...).
21459 \layout Subsubsection
21464 The PIC18F family of microcontrollers supports a number of interrupt sources.
21465 A list of these interrupts is shown in the following table:
21469 \begin_inset Tabular
21470 <lyxtabular version="3" rows="11" columns="4">
21472 <column alignment="left" valignment="top" leftline="true" width="0">
21473 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21474 <column alignment="left" valignment="top" leftline="true" width="0">
21475 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
21476 <row topline="true" bottomline="true">
21477 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21485 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21493 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21501 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21510 <row topline="true">
21511 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21519 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21524 PORTB change interrupt
21527 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21535 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21540 EEPROM/FLASH write complete interrupt
21544 <row topline="true">
21545 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21553 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21558 INT0 external interrupt
21561 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21569 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21574 Bus collision interrupt
21578 <row topline="true">
21579 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21587 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21592 INT1 external interrupt
21595 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21603 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21608 Low voltage detect interrupt
21612 <row topline="true">
21613 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21621 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21626 INT2 external interrupt
21629 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21637 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21642 Parallel slave port interrupt
21646 <row topline="true">
21647 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21655 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21660 CCP1 module interrupt
21663 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21671 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21676 AD convertion complete interrupt
21680 <row topline="true">
21681 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21689 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21694 CCP2 module interrupt
21697 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21705 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21710 USART receive interrupt
21714 <row topline="true">
21715 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21723 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21728 TMR0 overflow interrupt
21731 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21739 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21744 USART transmit interrupt
21748 <row topline="true">
21749 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21757 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21762 TMR1 overflow interrupt
21765 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21773 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21778 SSP receive/transmit interrupt
21782 <row topline="true">
21783 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21791 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21796 TMR2 matches PR2 interrupt
21799 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21806 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21814 <row topline="true" bottomline="true">
21815 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21823 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21828 TMR3 overflow interrupt
21831 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21838 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21853 The prototypes for these names are defined in the header file
21860 In order to simplify signal handling, a number of macros is provided:
21862 \labelwidthstring 00.00.0000
21864 DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
21865 high priority interrupts.
21870 is the function name to use.
21872 \labelwidthstring 00.00.0000
21874 DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
21875 low priority interrupt.
21880 is the function name to use.
21882 \labelwidthstring 00.00.0000
21884 DEF_HANDLER(sig,handler) define a handler for signal
21888 \labelwidthstring 00.00.0000
21890 END_DEF end the declaration of the dispatch table.
21893 Additionally there are two more macros to simplify the declaration of the
21896 \labelwidthstring 00.00.0000
21900 SIGHANDLER(handler)
21902 this declares the function prototype for the
21908 \labelwidthstring 00.00.0000
21910 SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
21913 An example of using the macros above is shown below:
21916 #include <pic18fregs.h>
21919 #include <signal.h>
21923 DEF_INTHIGH(high_int)
21926 DEF_HANDLER(SIG_TMR0, _tmr0_handler)
21929 DEF_HANDLER(SIG_BCOL, _bcol_handler)
21936 SIGHANDLER(_tmr0_handler)
21942 /* action to be taken when timer 0 overflows */
21949 SIGHANDLERNAKED(_bcol_handler)
21958 /* action to be taken when bus collision occurs */
21974 Special care should be taken when using the above scheme:
21977 do not place a colon (;) at the end of the DEF_* and END_DEF macros.
21980 when declaring SIGHANDLERNAKED handler never forget to use
21984 for proper returning.
21990 Here you can find some general tips for compiling programs with SDCC/pic16.
21991 \layout Subsubsection
21997 \begin_inset LatexCommand \index{PIC16!stack}
22001 size (that is 64 bytes) probably is enough for many programs.
22002 One must take care that when there are many levels of function nesting,
22003 or there is excessive usage of stack, its size should be extended.
22004 An example of such a case is the printf/sprintf family of functions.
22005 If you encounter problems like not being able to print integers, then you
22006 need to set the stack size around the maximum (256 for small stack model).
22007 The following diagram shows what happens when calling printf to print an
22011 printf () --> ltoa () --> ultoa () --> divschar ()
22014 It is should be understood that stack is easily consumed when calling complicate
22016 Using command line arguments like -
22026 -fommit-frame-pointer might reduce stack usage by not creating unnecessery
22028 Other ways to reduce stack usage may exist.
22034 The PIC16 Port currently does not pass SDCC's regression test
22035 \begin_inset LatexCommand \index{Regression test (PIC16)}
22040 \begin_inset LatexCommand \ref{sec:Quality-control}
22044 ) and thus the nightly regression tests for the PIC16 target are currently
22045 disabled for all hosts except for
22050 This means you can see the result of the PIC16 regression tests f.e.
22051 by checking the log files in
22052 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/regression_test_results/amd64-unknown-linux2.3/}
22056 (pick the most up to date file there, scroll down, lend a hand).
22062 There are several approaches to debugging your code.
22063 This chapter is meant to show your options and to give detail on some of
22068 When writing your code:
22071 write your code with debugging in mind (avoid duplicating code, put conceptually
22072 similar variables into structs, use structured code, have strategic points
22073 within your code where all variables are consistent, ...)
22076 run a syntax-checking tool like splint
22077 \begin_inset LatexCommand \index{splint (syntax checking tool)}
22082 \begin_inset LatexCommand \index{lint (syntax checking tool)}
22097 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
22104 for the high level code use a C-compiler (like f.e.
22105 GCC) to compile run and debug the code on your host.
22117 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
22121 ) on howto handle syntax extensions like __xdata, __at(), ...
22125 use another C-compiler to compile code for your target.
22126 Always an option but not recommended:) And not very likely to help you.
22127 If you seriously consider walking this path you should at least occasionally
22128 check portability of your code.
22129 Most commercial compiler vendors will offer an evaluation version so you
22130 can test compile your code or snippets of your code.
22133 Debugging on a simulator:
22136 there is a separate section about SDCDB (section
22137 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
22144 or (8051 specific) use a freeware/commercial simulator which interfaces
22146 \begin_inset LatexCommand \index{AOMF, AOMF51}
22151 \begin_inset LatexCommand \ref{OMF file}
22155 ) optionally generated by SDCC.
22158 Debugging On-target:
22161 use a MCU port pin to serially output debug data to the RS232 port of your
22163 You'll probably want some level shifting device typically involving a MAX232
22165 If the hardware serial port of the MCU is not available search for 'Software
22166 UART' in your favourite search machine.
22169 use an on-target monitor.
22170 In this context a monitor is a small program which usually accepts commands
22171 via a serial line and allows to set program counter, to single step through
22172 a program and read/write memory locations.
22173 For the 8051 good examples of monitors are paulmon and cmon51 (see section
22175 \begin_inset LatexCommand \ref{sec:Related-open-source-tools}
22182 toggle MCU port pins at strategic points within your code and use an oscilloscop
22186 digital oscilloscope
22189 \begin_inset LatexCommand \index{Oscilloscope}
22193 with deep trace memory is really helpful especially if you have to debug
22194 a realtime application.
22195 If you need to monitor more pins than your oscilloscope provides you can
22196 sometimes get away with a small R-2R network.
22197 On a single channel oscilloscope you could f.e.
22198 monitor 2 push-pull driven pins by connecting one via a 10\SpecialChar ~
22200 \begin_inset Formula $\Omega$
22203 resistor and the other one by a 5\SpecialChar ~
22205 \begin_inset Formula $\Omega$
22208 resistor to the oscilloscope probe (check output drive capability of the
22209 pins you want to monitor).
22210 If you need to monitor many more pins a
22230 \begin_inset LatexCommand \index{ICE (in circuit emulator)}
22235 Usually very expensive.
22236 And very nice to have too.
22237 And usually locks you (for years...) to the devices the ICE can emulate.
22241 use a remote debugger.
22242 In most 8-bit systems the symbol information is not available on the target,
22243 and a complete debugger is too bulky for the target system.
22244 Therefore usually a debugger on the host system connects to an on-target
22245 debugging stub which accepts only primitive commands.
22248 Terms to enter into your favourite search engine could be 'remote debugging',
22249 'gdb stub' or 'inferior debugger'.
22253 use an on target hardware debugger.
22254 Some of the more modern MCUs include hardware support for setting break
22255 points and monitoring/changing variables by using dedicated hardware pins.
22256 This facility doesn't require additional code to run on the target and
22261 doesn't affect runtime behaviour until a breakpoint is hit.
22262 For the mcs51 most hardware debuggers use the AOMF
22263 \begin_inset LatexCommand \index{AOMF, AOMF51}
22268 \begin_inset LatexCommand \ref{OMF file}
22279 if you are not familiar with any of the following terms you're likely to
22280 run into problems rather sooner than later:
22297 As an embedded programmer you
22301 to know them so why not look them up
22305 you have problems?)
22308 tell someone else about your problem (actually this is a surprisingly effective
22309 means to hunt down the bug even if the listener is not familiar with your
22311 As 'failure to communicate' is probably one of the job-induced deformations
22312 of an embedded programmer this is highly encouraged.
22315 Debugging with SDCDB
22316 \begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
22321 \begin_inset LatexCommand \index{SDCDB (debugger)}
22328 SDCC is distributed with a source level debugger
22329 \begin_inset LatexCommand \index{Debugger}
22334 The debugger uses a command line interface, the command repertoire of the
22335 debugger has been kept as close to gdb
22336 \begin_inset LatexCommand \index{gdb}
22340 (the GNU debugger) as possible.
22341 The configuration and build process is part of the standard compiler installati
22342 on, which also builds and installs the debugger in the target directory
22343 specified during configuration.
22344 The debugger allows you debug BOTH at the C source and at the ASM source
22348 Compiling for Debugging
22362 \begin_inset LatexCommand \index{-\/-debug}
22366 option must be specified for all files for which debug information is to
22368 The compiler generates a .adb file for each of these files.
22369 The linker creates the .cdb
22370 \begin_inset LatexCommand \index{<file>.cdb}
22375 \begin_inset LatexCommand \index{<file>.adb}
22379 files and the address information.
22380 This .cdb is used by the debugger.
22383 How the Debugger Works
22396 -debug option is specified the compiler generates extra symbol information
22397 some of which are put into the assembler source and some are put into the
22399 Then the linker creates the .cdb file from the individual .adb files with
22400 the address information for the symbols.
22401 The debugger reads the symbolic information generated by the compiler &
22402 the address information generated by the linker.
22403 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
22404 execution is controlled by the debugger.
22405 When a command is issued for the debugger, it translates it into appropriate
22406 commands for the simulator.
22407 (Currently SDCDM only connects to the simulator but
22412 \begin_inset LatexCommand \url{http://ec2drv.sf.net/}
22416 is an effort to connect directly to the hardware.)
22419 Starting the Debugger SDCDB
22422 The debugger can be started using the following command line.
22423 (Assume the file you are debugging has the file name foo).
22437 The debugger will look for the following files.
22440 foo.c - the source file.
22443 foo.cdb - the debugger symbol information file.
22446 foo.ihx - the Intel hex format
22447 \begin_inset LatexCommand \index{Intel hex format}
22454 SDCDB Command Line Options
22467 -directory=<source file directory> this option can used to specify the directory
22469 The debugger will look into the directory list specified for source, cdb
22471 The items in the directory list must be separated by ':', e.g.
22472 if the source files can be in the directories /home/src1 and /home/src2,
22483 -directory option should be -
22493 -directory=/home/src1:/home/src2.
22494 Note there can be no spaces in the option.
22498 -cd <directory> - change to the <directory>.
22501 -fullname - used by GUI front ends.
22504 -cpu <cpu-type> - this argument is passed to the simulator please see the
22505 simulator docs for details.
22508 -X <Clock frequency > this options is passed to the simulator please see
22509 the simulator docs for details.
22512 -s <serial port file> passed to simulator see the simulator docs for details.
22515 -S <serial in,out> passed to simulator see the simulator docs for details.
22518 -k <port number> passed to simulator see the simulator docs for details.
22521 SDCDB Debugger Commands
22524 As mentioned earlier the command interface for the debugger has been deliberatel
22525 y kept as close the GNU debugger gdb, as possible.
22526 This will help the integration with existing graphical user interfaces
22527 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
22528 If you use a graphical user interface for the debugger you can skip this
22530 \layout Subsubsection*
22532 break [line | file:line | function | file:function]
22535 Set breakpoint at specified line or function:
22544 sdcdb>break foo.c:100
22546 sdcdb>break funcfoo
22548 sdcdb>break foo.c:funcfoo
22549 \layout Subsubsection*
22551 clear [line | file:line | function | file:function ]
22554 Clear breakpoint at specified line or function:
22563 sdcdb>clear foo.c:100
22565 sdcdb>clear funcfoo
22567 sdcdb>clear foo.c:funcfoo
22568 \layout Subsubsection*
22573 Continue program being debugged, after breakpoint.
22574 \layout Subsubsection*
22579 Execute till the end of the current function.
22580 \layout Subsubsection*
22585 Delete breakpoint number 'n'.
22586 If used without any option clear ALL user defined break points.
22587 \layout Subsubsection*
22589 info [break | stack | frame | registers ]
22592 info break - list all breakpoints
22595 info stack - show the function call stack.
22598 info frame - show information about the current execution frame.
22601 info registers - show content of all registers.
22602 \layout Subsubsection*
22607 Step program until it reaches a different source line.
22608 Note: pressing <return> repeats the last command.
22609 \layout Subsubsection*
22614 Step program, proceeding through subroutine calls.
22615 \layout Subsubsection*
22620 Start debugged program.
22621 \layout Subsubsection*
22626 Print type information of the variable.
22627 \layout Subsubsection*
22632 print value of variable.
22633 \layout Subsubsection*
22638 load the given file name.
22639 Note this is an alternate method of loading file for debugging.
22640 \layout Subsubsection*
22645 print information about current frame.
22646 \layout Subsubsection*
22651 Toggle between C source & assembly source.
22652 \layout Subsubsection*
22654 ! simulator command
22657 Send the string following '!' to the simulator, the simulator response is
22659 Note the debugger does not interpret the command being sent to the simulator,
22660 so if a command like 'go' is sent the debugger can loose its execution
22661 context and may display incorrect values.
22662 \layout Subsubsection*
22669 My name is Bobby Brown"
22672 Interfacing SDCDB with DDD
22675 The screenshot was converted from png to eps with:
22676 \begin_inset Quotes sld
22679 bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
22680 \begin_inset Quotes srd
22683 which produces a pretty compact eps file which is free from compression
22687 The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
22688 as this broke the build system on Sourceforge (pdf-file was broken.
22689 pdflatex does not accept eps files).
22707 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
22713 shows a screenshot of a debugging session with DDD
22714 \begin_inset LatexCommand \index{DDD (debugger)}
22718 (Unix only) on a simulated 8032.
22719 The debugging session might not run as smoothly as the screenshot suggests.
22720 The debugger allows setting of breakpoints, displaying and changing variables,
22721 single stepping through C and assembler code.
22724 The source was compiled with
22747 -debug ddd_example.c
22760 and DDD was invoked with
22767 ddd -debugger 'sdcdb -cpu 8032 ddd_example'
22770 Interfacing SDCDB with XEmacs
22771 \begin_inset LatexCommand \index{XEmacs}
22776 \begin_inset LatexCommand \index{Emacs}
22783 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
22784 sdcdb.el and sdcdbsrc.el.
22785 These two files can be found in the $(prefix)/bin directory after the installat
22787 These files need to be loaded into XEmacs for the interface to work.
22788 This can be done at XEmacs startup time by inserting the following into
22789 your '.xemacs' file (which can be found in your HOME directory):
22795 (load-file sdcdbsrc.el)
22801 .xemacs is a lisp file so the () around the command is REQUIRED.
22802 The files can also be loaded dynamically while XEmacs is running, set the
22803 environment variable 'EMACSLOADPATH' to the installation bin directory
22804 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
22805 To start the interface enter the following command:
22819 You will prompted to enter the file name to be debugged.
22824 The command line options that are passed to the simulator directly are bound
22825 to default values in the file sdcdbsrc.el.
22826 The variables are listed below, these values maybe changed as required.
22829 sdcdbsrc-cpu-type '51
22832 sdcdbsrc-frequency '11059200
22835 sdcdbsrc-serial nil
22838 The following is a list of key mapping for the debugger interface.
22849 ;;key\SpecialChar ~
22863 binding\SpecialChar ~
22887 ;;---\SpecialChar ~
22901 -------\SpecialChar ~
22943 sdcdb-next-from-src\SpecialChar ~
22971 sdcdb-back-from-src\SpecialChar ~
22999 sdcdb-cont-from-src\SpecialChar ~
23009 SDCDB continue command
23027 sdcdb-step-from-src\SpecialChar ~
23055 sdcdb-whatis-c-sexp\SpecialChar ~
23065 SDCDB ptypecommand for data at
23132 sdcdbsrc-delete\SpecialChar ~
23146 SDCDB Delete all breakpoints if no arg
23195 given or delete arg (C-u arg x)
23213 sdcdbsrc-frame\SpecialChar ~
23228 SDCDB Display current frame if no arg,
23277 given or display frame arg
23344 sdcdbsrc-goto-sdcdb\SpecialChar ~
23354 Goto the SDCDB output buffer
23372 sdcdb-print-c-sexp\SpecialChar ~
23383 SDCDB print command for data at
23450 sdcdbsrc-goto-sdcdb\SpecialChar ~
23460 Goto the SDCDB output buffer
23478 sdcdbsrc-mode\SpecialChar ~
23494 Toggles Sdcdbsrc mode (turns it off)
23509 sdcdb-finish-from-src\SpecialChar ~
23517 SDCDB finish command
23532 sdcdb-break\SpecialChar ~
23550 Set break for line with point
23565 sdcdbsrc-mode\SpecialChar ~
23581 Toggle Sdcdbsrc mode
23596 sdcdbsrc-srcmode\SpecialChar ~
23619 Here are a few guidelines that will help the compiler generate more efficient
23620 code, some of the tips are specific to this compiler others are generally
23621 good programming practice.
23624 Use the smallest data type to represent your data-value.
23625 If it is known in advance that the value is going to be less than 256 then
23626 use an 'unsigned char' instead of a 'short' or 'int'.
23627 Please note, that ANSI C requires both signed and unsigned chars to be
23628 promoted to 'signed int'
23629 \begin_inset LatexCommand \index{promotion to signed int}
23634 \begin_inset Marginal
23645 before doing any operation.
23647 \begin_inset LatexCommand \index{type promotion}
23652 \begin_inset LatexCommand \label{type promotion}
23656 can be omitted, if the result is the same.
23657 The effect of the promotion rules together with the sign-extension is often
23664 unsigned char uc = 0xfe;
23666 if (uc * uc < 0) /* this is true! */
23685 (int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
23695 (unsigned char) -12 / (signed char) -3 = ...
23698 No, the result is not 4:
23703 (int) (unsigned char) -12 / (int) (signed char) -3 =
23705 (int) (unsigned char) 0xf4 / (int) (signed char) 0xfd =
23707 (int) 0x00f4 / (int) 0xfffd =
23709 (int) 0x00f4 / (int) 0xfffd =
23711 (int) 244 / (int) -3 =
23713 (int) -81 = (int) 0xffaf;
23716 Don't complain, that gcc gives you a different result.
23717 gcc uses 32 bit ints, while SDCC uses 16 bit ints.
23718 Therefore the results are different.
23721 \begin_inset Quotes sld
23725 \begin_inset Quotes srd
23733 If well-defined overflow characteristics are important and negative values
23734 are not, or if you want to steer clear of sign-extension problems when
23735 manipulating bits or bytes, use one of the corresponding unsigned types.
23736 (Beware when mixing signed and unsigned values in expressions, though.)
23738 Although character types (especially unsigned char) can be used as "tiny"
23739 integers, doing so is sometimes more trouble than it's worth, due to unpredicta
23740 ble sign extension and increased code size.
23744 Use unsigned when it is known in advance that the value is not going to
23746 This helps especially if you are doing division or multiplication, bit-shifting
23747 or are using an array index.
23750 NEVER jump into a LOOP.
23753 Declare the variables to be local
23754 \begin_inset LatexCommand \index{local variables}
23758 whenever possible, especially loop control variables (induction).
23761 Have a look at the assembly listing to get a
23762 \begin_inset Quotes sld
23766 \begin_inset Quotes srd
23769 for the code generation.
23772 Porting code from or to other compilers
23773 \begin_inset LatexCommand \label{sec:Porting-code-to-other-compilers}
23780 check whether endianness of the compilers differs and adapt where needed.
23783 check the device specific header files
23784 \begin_inset LatexCommand \index{Header files}
23789 \begin_inset LatexCommand \index{Include files}
23793 for compiler specific syntax.
23794 Eventually include the file <compiler.h
23795 \begin_inset LatexCommand \index{compiler.h (include file)}
23800 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}
23804 to allow using common header files.
23807 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}
23814 check whether the startup code contains the correct initialization (watchdog,
23818 check whether the sizes of short, int, long match.
23821 check if some 16 or 32 bit hardware registers require a specific addressing
23822 order (least significant or most significant byte first) and adapt if needed
23831 relate to time and not to lower/upper memory location here, so this is
23836 the same as endianness).
23839 check whether the keyword
23843 is used where needed.
23844 The compilers might differ in their optimization characteristics (as different
23845 versions of the same compiler might also use more clever optimizations
23846 this is good idea anyway).
23848 \begin_inset LatexCommand \ref{sub:Common-interrupt-pitfall-volatile}
23855 check that the compilers are not told to supress warnings.
23858 check and convert compiler specific extensions (interrupts, memory areas,
23862 check for differences in type promotion.
23863 Especially check for math operations on
23872 For the sake of C99 compatibility SDCC will probably promote these to
23876 more often than other compilers.
23877 Eventually insert explicit casts to
23886 Also check that the ~\SpecialChar ~
23888 \begin_inset LatexCommand \index{\~\/ Operator}
23895 \begin_inset LatexCommand \index{bit}
23901 variables, use the !\SpecialChar ~
23904 \begin_inset LatexCommand \ref{type promotion}
23909 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23916 check the assembly code generated for interrupt routines (f.e.
23917 for calls to possibly non-reentrant library functions).
23920 check whether timing loops result in proper timing (or preferably consider
23921 a rewrite of the code with timer based delays instead).
23924 check for differences in printf parameters (some compilers push (va_arg
23925 \begin_inset LatexCommand \index{vararg, va\_arg}
23929 ) char variables as
23933 others push them as
23939 \begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
23946 check the resulting memory map
23947 \begin_inset LatexCommand \index{Memory map}
23952 Usage of different memory spaces: code, stack, data (for mcs51/ds390 additional
23953 ly idata, pdata, xdata).
23954 Eventually check if unexpected library functions are included.
23958 \begin_inset LatexCommand \index{Tools}
23962 included in the distribution
23966 \begin_inset Tabular
23967 <lyxtabular version="3" rows="12" columns="3">
23969 <column alignment="left" valignment="top" leftline="true" width="0pt">
23970 <column alignment="left" valignment="top" leftline="true" width="0pt">
23971 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
23972 <row topline="true" bottomline="true">
23973 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23983 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
23993 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24004 <row topline="true">
24005 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24013 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24018 Simulator for various architectures
24021 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24030 <row topline="true">
24031 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24039 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24045 \begin_inset LatexCommand \index{Header files}
24050 \begin_inset LatexCommand \index{Include files}
24057 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24062 sdcc/support/scripts
24066 <row topline="true">
24067 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24075 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24080 header file conversion
24083 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24088 sdcc/support/scripts
24092 <row topline="true">
24093 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24101 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24109 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24127 <row topline="true">
24128 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24136 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24144 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24162 <row topline="true">
24163 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24171 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24179 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24197 <row topline="true">
24198 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24206 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24214 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24232 <row topline="true">
24233 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24241 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24249 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24267 <row topline="true">
24268 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24276 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24284 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24302 <row topline="true">
24303 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24311 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24319 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24337 <row topline="true" bottomline="true">
24338 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24346 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24352 \begin_inset LatexCommand \index{packihx (tool)}
24359 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24387 \begin_inset LatexCommand \index{Documentation}
24391 included in the distribution
24395 \begin_inset Tabular
24396 <lyxtabular version="3" rows="10" columns="2">
24398 <column alignment="block" valignment="top" leftline="true" width="40col%">
24399 <column alignment="block" valignment="top" leftline="true" rightline="true" width="60col%">
24400 <row topline="true" bottomline="true" endhead="true">
24401 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24411 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24418 Filename / Where to get
24422 <row topline="true">
24423 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24428 SDCC Compiler User Guide
24431 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24436 You're reading it right now
24448 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}
24456 <row topline="true">
24457 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24465 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24482 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/ChangeLog}
24490 <row topline="true">
24491 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24497 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
24502 \begin_inset LatexCommand \index{Assembler documentation}
24509 \begin_inset LatexCommand \index{aslink}
24514 \begin_inset LatexCommand \index{Linker documentation}
24521 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24526 sdcc/as/doc/asxhtm.html
24538 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
24546 <row topline="true">
24547 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24552 SDCC regression test
24553 \begin_inset LatexCommand \index{Regression test}
24560 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24565 sdcc/doc/test_suite_spec.pdf
24577 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}
24585 <row topline="true">
24586 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24594 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24611 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/doc/}
24619 <row topline="true">
24620 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24625 Notes on debugging with SDCDB
24626 \begin_inset LatexCommand \index{SDCDB (debugger)}
24633 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24638 sdcc/debugger/README
24650 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/debugger/README}
24658 <row topline="true">
24659 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24664 Software simulator for microcontrollers
24667 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24702 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/sim/ucsim/doc/index.html}
24710 <row topline="true">
24711 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24716 Temporary notes on the pic16
24717 \begin_inset LatexCommand \index{PIC16}
24724 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24729 sdcc/src/pic16/NOTES
24741 \begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/src/pic16/NOTES}
24749 <row topline="true" bottomline="true">
24750 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24755 SDCC internal documentation (debugging file format)
24758 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24793 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/cdbfileformat.pdf}
24810 Related open source tools
24811 \begin_inset LatexCommand \label{sec:Related-open-source-tools}
24816 \begin_inset LatexCommand \index{Related tools}
24824 \begin_inset Tabular
24825 <lyxtabular version="3" rows="14" columns="3">
24827 <column alignment="left" valignment="top" leftline="true" width="0pt">
24828 <column alignment="block" valignment="top" leftline="true" width="30line%">
24829 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
24830 <row topline="true" bottomline="true">
24831 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24841 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24851 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24862 <row topline="true">
24863 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24869 \begin_inset LatexCommand \index{gpsim (pic simulator)}
24876 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24884 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24890 \begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
24898 <row topline="true">
24899 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24905 \begin_inset LatexCommand \index{gputils (pic tools)}
24912 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24920 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24926 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
24934 <row topline="true">
24935 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24943 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24951 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24957 \begin_inset LatexCommand \url{http://freshmeat.net/projects/flp5/}
24965 <row topline="true">
24966 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24974 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
24979 Tools for Silicon Laboratories JTAG debug adapter, partly based on SDCDB
24983 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
24989 \begin_inset LatexCommand \url{http://sourceforge.net/projects/ec2drv}
24997 <row topline="true">
24998 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25004 \begin_inset LatexCommand \index{indent (source formatting tool)}
25011 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25016 Formats C source - Master of the white spaces
25019 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25025 \begin_inset LatexCommand \url{http://directory.fsf.org/GNU/indent.html}
25033 <row topline="true">
25034 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25040 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
25047 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25052 Object file conversion, checksumming, ...
25055 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25061 \begin_inset LatexCommand \url{http://sourceforge.net/projects/srecord}
25069 <row topline="true">
25070 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25076 \begin_inset LatexCommand \index{objdump (tool)}
25083 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25088 Object file conversion, ...
25091 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25096 Part of binutils (should be there anyway)
25100 <row topline="true">
25101 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25109 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25114 8051 monitor (hex up-/download, single step, disassemble)
25117 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25123 \begin_inset LatexCommand \url{http://sourceforge.net/projects/cmon51}
25131 <row topline="true">
25132 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25138 \begin_inset LatexCommand \index{doxygen (source documentation tool)}
25145 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25150 Source code documentation system
25153 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25159 \begin_inset LatexCommand \url{http://www.doxygen.org}
25167 <row topline="true">
25168 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25176 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25181 IDE (has anyone tried integrating SDCC & SDCDB? Unix only)
25184 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25190 \begin_inset LatexCommand \url{http://www.kdevelop.org}
25198 <row topline="true">
25199 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25207 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25212 8051 monitor (hex up-/download, single step, disassemble)
25215 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25221 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/paulmon2.html}
25229 <row topline="true">
25230 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25236 \begin_inset LatexCommand \index{splint (syntax checking tool)}
25243 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25248 Statically checks c sources (see
25249 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
25256 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25262 \begin_inset LatexCommand \url{http://www.splint.org}
25270 <row topline="true" bottomline="true">
25271 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25277 \begin_inset LatexCommand \index{DDD (debugger)}
25284 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25289 Debugger, serves nicely as GUI to SDCDB
25290 \begin_inset LatexCommand \index{SDCDB (debugger)}
25297 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25303 \begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
25320 Related documentation / recommended reading
25324 \begin_inset Tabular
25325 <lyxtabular version="3" rows="7" columns="3">
25327 <column alignment="left" valignment="top" leftline="true" width="0pt">
25328 <column alignment="left" valignment="top" leftline="true" width="0">
25329 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
25330 <row topline="true" bottomline="true">
25331 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25341 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25351 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25362 <row topline="true">
25363 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25380 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25386 \begin_inset LatexCommand \index{C Reference card}
25393 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25399 \begin_inset LatexCommand \url{http://refcards.com/refcards/c/index.html}
25407 <row topline="true">
25408 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25416 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25422 \begin_inset LatexCommand \index{C FAQ}
25429 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25435 \begin_inset LatexCommand \url{http://www.c-faq.com}
25443 <row topline="true">
25444 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25452 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25458 \begin_inset Quotes sld
25462 \begin_inset Quotes srd
25468 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25476 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
25484 <row topline="true">
25485 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25493 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25499 \begin_inset Quotes sld
25502 Extensions for Embedded C
25503 \begin_inset Quotes srd
25509 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25517 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1021.pdf}
25525 <row topline="true">
25526 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25533 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25538 Latest datasheet of target CPU
25541 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25550 <row topline="true" bottomline="true">
25551 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25558 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25563 Revision history of datasheet
25566 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25584 Application notes specifically for SDCC
25587 SDCC makes no claims about the completeness of this list and about up-to-datenes
25588 s or correctness of the application notes
25589 \begin_inset LatexCommand \index{Application notes}
25599 \begin_inset Tabular
25600 <lyxtabular version="3" rows="7" columns="3">
25602 <column alignment="block" valignment="top" leftline="true" width="17col%">
25603 <column alignment="block" valignment="top" leftline="true" width="27col%">
25604 <column alignment="block" valignment="top" leftline="true" rightline="true" width="57col%">
25605 <row topline="true" bottomline="true">
25606 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25617 <cell alignment="left" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
25628 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25640 <row topline="true">
25641 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25651 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25658 Using the SDCC Compiler for the DS80C400
25659 \begin_inset LatexCommand \index{DS80C400}
25666 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25674 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3346.pdf}
25682 <row topline="true">
25683 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25693 <cell multicolumn="1" alignment="left" valignment="top" topline="true" leftline="true" usebox="none" width="30line%">
25700 Using the Free SDCC C Compiler to Develop Firmware for the DS89C420/430/440/450
25701 \begin_inset LatexCommand \index{DS89C4x0}
25705 Family of Microcontrollers
25708 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25716 \begin_inset LatexCommand \url{http://pdfserv.maxim-ic.com/en/an/AN3477.pdf}
25724 <row topline="true">
25725 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25732 Silicon Laboratories / Cygnal
25735 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25742 Integrating SDCC 8051 Tools Into The Silicon Labs IDE
25743 \begin_inset LatexCommand \index{IDE}
25750 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25758 \begin_inset LatexCommand \url{http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/en/an198.pdf}
25766 <row topline="true">
25767 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25774 Ramtron / Goal Semiconductor
25777 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25784 Interfacing SDCC to Syn and Textpad
25787 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25795 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25803 <row topline="true">
25804 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25811 Ramtron / Goal Semiconductor
25814 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25821 Installing and Configuring SDCC and Crimson Editor
25824 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25832 \begin_inset LatexCommand \url{http://www.ramtron.com/doc/Products/Microcontroller/Support_Tools.asp}
25840 <row topline="true" bottomline="true">
25841 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25851 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
25858 MSC12xx Programming with SDCC
25861 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
25869 \begin_inset LatexCommand \url{http://focus.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sbaa109&fileType=pdf}
25887 Some questions answered, some pointers given - it might be time to in turn
25895 can you solve your project with the selected microcontroller? Would you
25896 find out early or rather late that your target is too small/slow/whatever?
25897 Can you switch to a slightly better device if it doesn't fit?
25900 should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
25901 and/or another programming language be more adequate? Would an operating
25902 system on the target device help?
25905 if you solved the problem, will the marketing department be happy?
25908 if the marketing department is happy, will customers be happy?
25911 if you're the project manager, marketing department and maybe even the customer
25912 in one person, have you tried to see the project from the outside?
25915 is the project done if you think it is done? Or is just that other interface/pro
25916 tocol/feature/configuration/option missing? How about website, manual(s),
25917 internationali(z|s)ation, packaging, labels, 2nd source for components,
25918 electromagnetic compatability/interference, documentation for production,
25919 production test software, update mechanism, patent issues?
25922 is your project adequately positioned in that magic triangle: fame, fortune,
25926 Maybe not all answers to these questions are known and some answers may
25931 , nevertheless knowing these questions may help you to avoid burnout
25937 burnout is bad for electronic devices, programmers and motorcycle tyres
25941 Chances are you didn't want to hear some of them...
25945 \begin_inset LatexCommand \index{Support}
25952 SDCC has grown to be a large project.
25953 The compiler alone (without the preprocessor, assembler and linker) is
25954 well over 150,000 lines of code (blank stripped).
25955 The open source nature of this project is a key to its continued growth
25957 You gain the benefit and support of many active software developers and
25959 Is SDCC perfect? No, that's why we need your help.
25960 The developers take pride in fixing reported bugs.
25961 You can help by reporting the bugs and helping other SDCC users.
25962 There are lots of ways to contribute, and we encourage you to take part
25963 in making SDCC a great software package.
25967 The SDCC project is hosted on the SDCC sourceforge site at
25968 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
25973 You'll find the complete set of mailing lists
25974 \begin_inset LatexCommand \index{Mailing list(s)}
25978 , forums, bug reporting system, patch submission
25979 \begin_inset LatexCommand \index{Patch submission}
25984 \begin_inset LatexCommand \index{download}
25988 area and Subversion code repository
25989 \begin_inset LatexCommand \index{Subversion code repository}
25997 \begin_inset LatexCommand \index{Bug reporting}
26002 \begin_inset LatexCommand \index{Reporting bugs}
26009 The recommended way of reporting bugs is using the infrastructure of the
26011 You can follow the status of bug reports there and have an overview about
26015 Bug reports are automatically forwarded to the developer mailing list and
26016 will be fixed ASAP.
26017 When reporting a bug, it is very useful to include a small test program
26018 (the smaller the better) which reproduces the problem.
26019 If you can isolate the problem by looking at the generated assembly code,
26020 this can be very helpful.
26021 Compiling your program with the -
26032 \begin_inset LatexCommand \index{-\/-dumpall}
26036 option can sometimes be useful in locating optimization problems.
26037 When reporting a bug please make sure you:
26040 Attach the code you are compiling with SDCC.
26044 Specify the exact command you use to run SDCC, or attach your Makefile.
26048 Specify the SDCC version (type "
26054 "), your platform, and operating system.
26058 Provide an exact copy of any error message or incorrect output.
26062 Put something meaningful in the subject of your message.
26065 Please attempt to include these 5 important parts, as applicable, in all
26066 requests for support or when reporting any problems or bugs with SDCC.
26067 Though this will make your message lengthy, it will greatly improve your
26068 chance that SDCC users and developers will be able to help you.
26069 Some SDCC developers are frustrated by bug reports without code provided
26070 that they can use to reproduce and ultimately fix the problem, so please
26071 be sure to provide sample code if you are reporting a bug!
26074 Please have a short check that you are using a recent version of SDCC and
26075 the bug is not yet known.
26076 This is the link for reporting bugs:
26077 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
26082 With SDCC on average having more than 200 downloads
26083 \begin_inset LatexCommand \index{download}
26087 on sourceforge per day
26093 220 daily downloads on average Jan-Sept 2006 and about 150 daily downloads
26094 between 2002 and 2005.
26095 This does not include other methods of distribution.
26098 there must be some users.
26099 So it's not exactly easy to find a new bug.
26100 If you find one we need it:
26102 reporting bugs is good
26107 Requesting Features
26108 \begin_inset LatexCommand \label{sub:Requesting-Features}
26113 \begin_inset LatexCommand \index{Feature request}
26118 \begin_inset LatexCommand \index{Requesting features}
26125 Like bug reports feature requests are forwarded to the developer mailing
26127 This is the link for requesting features:
26128 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
26138 Like bug reports contributed patches are forwarded to the developer mailing
26140 This is the link for submitting patches
26141 \begin_inset LatexCommand \index{Patch submission}
26146 \begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}
26153 You need to specify some parameters to the
26157 command for the patches to be useful.
26158 If you modified more than one file a patch created f.e.
26163 \begin_inset Quotes sld
26166 diff -Naur unmodified_directory modified_directory >my_changes.patch
26167 \begin_inset Quotes srd
26173 will be fine, otherwise
26177 \begin_inset Quotes sld
26180 diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
26181 \begin_inset Quotes srd
26194 These links should take you directly to the
26195 \begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
26205 Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
26206 automated messages (mid 2003)
26210 \begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
26215 \begin_inset LatexCommand \index{Mailing list(s)}
26219 and forums are archived and searchable so if you are lucky someone already
26220 had a similar problem.
26221 While mails to the lists themselves are delivered promptly their web front
26222 end on sourceforge sometimes shows a severe time lag (up to several weeks),
26223 if you're seriously using SDCC please consider subscribing to the lists.
26229 You can follow the status of the Subversion version
26230 \begin_inset LatexCommand \index{version}
26234 of SDCC by watching the Changelog
26235 \begin_inset LatexCommand \index{Changelog}
26239 in the Subversion repository
26242 \begin_inset LatexCommand \htmlurl{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}
26249 Subversion Source Code Repository
26258 or the filenames of the snapshot versions of SDCC include date and its
26260 \begin_inset LatexCommand \index{Subversion code repository}
26265 Subversion allows to download the source of recent or previous versions
26267 \begin_inset LatexCommand \url{http://sourceforge.net/svn/?group_id=599}
26271 (by number or by date).
26272 An on-line source code browser and detailled instructions are also available
26274 SDCC versions starting from 1999 up to now are available (currently the
26275 versions prior to the conversion from cvs
26276 \begin_inset LatexCommand \index{cvs|see{Subversion}}
26280 to Subversion (April 2006) are either by accessible by Subversion or by
26285 \begin_inset LatexCommand \index{Release policy}
26292 Historically there often were long delays between official releases and
26293 the sourceforge download area tends to get not updated at all.
26294 Excuses in the past might have referred to problems with live range analysis,
26295 but as this was fixed a while ago, the current problem is that another
26296 excuse has to be found.
26297 Kidding aside, we have to get better there! On the other hand there are
26298 daily snapshots available at
26299 \begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
26303 , and you can always build the very last version (hopefully with many bugs
26304 fixed, and features added) from the source code available at
26305 \begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
26311 \begin_inset LatexCommand \index{wiki}
26316 \begin_inset LatexCommand \index{Release wiki}
26321 \begin_inset LatexCommand \url{http://sdcc.sf.net/release_wiki/}
26325 also holds some information about past and future releases.
26329 \begin_inset LatexCommand \index{Examples}
26336 You'll find some small examples in the directory
26338 sdcc/device/examples/.
26341 More examples and libraries are available at
26343 The SDCC Open Knowledge Resource
26344 \begin_inset LatexCommand \url{http://sdccokr.dl9sec.de/}
26351 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}
26358 I did insert a reference to Paul's web site here although it seems rather
26359 dedicated to a specific 8032 board (I think it's okay because it f.e.
26360 shows LCD/Harddisc interface and has a free 8051 monitor.
26361 Independent 8032 board vendors face hard competition of heavily subsidized
26362 development boards anyway).
26365 Maybe we should include some links to real world applications.
26366 Preferably pointer to pointers (one for each architecture) so this stays
26371 \begin_inset LatexCommand \label{sec:Quality-control}
26376 \begin_inset LatexCommand \index{Quality control}
26383 The compiler is passed through nightly compile and build checks.
26389 \begin_inset LatexCommand \index{Regression test}
26393 check that SDCC itself compiles flawlessly on several host platforms (i386,
26394 Opteron, 64 bit Alpha, ppc64, MacOS X on PPC, Solaris on Sparc) and checks
26395 the quality of the code generated by SDCC by running the code for several
26396 target platforms through simulators.
26397 The regression test suite comprises more than 100 files which expand to
26398 more than 500 test cases which include more than 4500 tests.
26399 The results of these tests are published daily on SDCC's snapshot page
26400 (click on the red or green symbols on the right side of
26401 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
26408 There is a separate document
26411 \begin_inset LatexCommand \index{Test suite}
26418 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/test_suite_spec.pdf}
26422 about the regression test suite.
26425 You'll find the test code in the directory
26427 sdcc/support/regression
26430 You can run these tests manually by running
26434 in this directory (or f.e.
26439 \begin_inset Quotes sld
26443 \begin_inset Quotes srd
26449 if you don't want to run the complete tests).
26450 The test code might also be interesting if you want to look for examples
26451 \begin_inset LatexCommand \index{Examples}
26455 checking corner cases of SDCC or if you plan to submit patches
26456 \begin_inset LatexCommand \index{Patch submission}
26463 The 14bit pic port uses a different set of regression tests
26464 \begin_inset LatexCommand \index{Regression test (PIC14)}
26468 , you'll find them in the directory
26470 sdcc/src/regression
26475 Use of SDCC in Education
26488 the phrase "use in education" might evoke the association "
26492 fit for use in education".
26493 This connotation is not intended but nevertheless risked as the licensing
26494 of SDCC makes it difficult to offer educational discounts
26498 If your rationales are to:
26501 give students a chance to understand the
26505 steps of code generation
26508 have a curriculum that can be extended for years.
26509 Then you could use an fpga board as target and your curriculum will seamlessly
26510 extend from logic synthesis (
26511 \begin_inset LatexCommand \url[http://www.opencores.org]{opencores.org}
26516 \begin_inset LatexCommand \url[Oregano]{http://www.oregano.at/ip/ip01.htm}
26520 ), over assembly programming, to C to FPGA compilers (
26521 \begin_inset LatexCommand \url[FPGAC]{http://sf.net/projects/fpgac}
26528 be able to insert excursions about skills like using a revision control
26529 system, submitting/applying patches, using a type-setting (as opposed to
26530 word-processing) engine LyX/LaTeX, using
26531 \begin_inset LatexCommand \url[SourceForge]{http://www.sf.net}
26536 \begin_inset LatexCommand \url[netiquette]{http://en.wikipedia.org/wiki/Netiquette}
26540 , understanding BSD/LGPL/GPL/Proprietary licensing, growth models of Open
26541 Source Software, CPU simulation, compiler regression tests
26542 \begin_inset LatexCommand \index{Regression test}
26549 And if there should be a shortage of ideas then you can always point students
26550 to the ever-growing feature request list
26551 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
26558 not tie students to a specific host platform and instead allow them to use
26563 choice (among them Alpha, i386, i386_64, MacOs, Mips, Sparc, Windows and
26565 \begin_inset LatexCommand \url[OLPC]{http://www.laptop.org}
26572 not encourage students to use illegal copies of educational software
26575 be immune to licensing/availability/price changes of the chosen tool chain
26578 be able to change to a new target platform without having to adopt a new
26582 have complete control over and insight into the tool chain
26585 make your students aware about the pros and cons of open source software
26589 give back to the public as you are probably at least partially publically
26593 give students a chance to publically prove their skills and to possibly
26594 see a world wide impact
26597 then SDCC is probably among the first choices.
26598 Well, probably SDCC might be the only choice.
26601 SDCC Technical Data
26605 \begin_inset LatexCommand \index{Optimizations}
26612 SDCC performs a host of standard optimizations in addition to some MCU specific
26617 Sub-expression Elimination
26618 \begin_inset LatexCommand \index{Subexpression elimination}
26625 The compiler does local and
26651 will be translated to
26663 Some subexpressions are not as obvious as the above example, e.g.:
26673 In this case the address arithmetic a->b[i] will be computed only once;
26674 the equivalent code in C would be.
26686 The compiler will try to keep these temporary variables in registers.
26689 Dead-Code Elimination
26690 \begin_inset LatexCommand \index{Dead-code elimination}
26711 i = 1; \SpecialChar ~
26720 global = 1;\SpecialChar ~
26733 global = 3;\SpecialChar ~
26758 \begin_inset LatexCommand \index{Copy propagation}
26814 Note: the dead stores created by this copy propagation will be eliminated
26815 by dead-code elimination.
26819 \begin_inset LatexCommand \index{Loop optimization}
26824 \begin_inset LatexCommand \label{sub:Loop-Optimizations}
26831 Two types of loop optimizations are done by SDCC
26839 of loop induction variables.
26840 In addition to the strength reduction the optimizer marks the induction
26841 variables and the register allocator tries to keep the induction variables
26842 in registers for the duration of the loop.
26843 Because of this preference of the register allocator
26844 \begin_inset LatexCommand \index{Register allocation}
26848 , loop induction optimization causes an increase in register pressure, which
26849 may cause unwanted spilling of other temporary variables into the stack
26850 \begin_inset LatexCommand \index{stack}
26855 The compiler will generate a warning message when it is forced to allocate
26856 extra space either on the stack or data space.
26857 If this extra space allocation is undesirable then induction optimization
26858 can be eliminated either for the entire source file (with -
26868 -noinduction option) or for a given function only using #pragma\SpecialChar ~
26870 \begin_inset LatexCommand \index{\#pragma noinduction}
26883 for (i = 0 ; i < 100 ; i ++)
26899 for (i = 0; i < 100; i++)
26908 As mentioned previously some loop invariants are not as apparent, all static
26909 address computations are also moved out of the loop.
26914 \begin_inset LatexCommand \index{Strength reduction}
26918 , this optimization substitutes an expression by a cheaper expression:
26923 for (i=0;i < 100; i++)
26941 for (i=0;i< 100;i++) {
26947 ar[itemp1] = itemp2;
26964 The more expensive multiplication
26965 \begin_inset LatexCommand \index{Multiplication}
26969 is changed to a less expensive addition.
26973 \begin_inset LatexCommand \index{Loop reversing}
26980 This optimization is done to reduce the overhead of checking loop boundaries
26981 for every iteration.
26982 Some simple loops can be reversed and implemented using a
26983 \begin_inset Quotes eld
26986 decrement and jump if not zero
26987 \begin_inset Quotes erd
26991 SDCC checks for the following criterion to determine if a loop is reversible
26992 (note: more sophisticated compilers use data-dependency analysis to make
26993 this determination, SDCC uses a more simple minded analysis).
26996 The 'for' loop is of the form
27002 for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
27012 The <for body> does not contain
27013 \begin_inset Quotes eld
27017 \begin_inset Quotes erd
27021 \begin_inset Quotes erd
27027 All goto's are contained within the loop.
27030 No function calls within the loop.
27033 The loop control variable <sym> is not assigned any value within the loop
27036 The loop control variable does NOT participate in any arithmetic operation
27040 There are NO switch statements in the loop.
27043 Algebraic Simplifications
27046 SDCC does numerous algebraic simplifications, the following is a small sub-set
27047 of these optimizations.
27052 i = j + 0;\SpecialChar ~
27056 /* changed to: */\SpecialChar ~
27062 i /= 2;\SpecialChar ~
27069 /* changed to: */\SpecialChar ~
27075 i = j - j;\SpecialChar ~
27079 /* changed to: */\SpecialChar ~
27085 i = j / 1;\SpecialChar ~
27089 /* changed to: */\SpecialChar ~
27096 Note the subexpressions
27097 \begin_inset LatexCommand \index{Subexpression}
27101 given above are generally introduced by macro expansions or as a result
27102 of copy/constant propagation.
27105 'switch' Statements
27106 \begin_inset LatexCommand \label{sub:'switch'-Statements}
27111 \begin_inset LatexCommand \index{switch statement}
27118 SDCC can optimize switch statements to jump tables
27119 \begin_inset LatexCommand \index{jump tables}
27124 It makes the decision based on an estimate of the generated code size.
27125 SDCC is quite liberal in the requirements for jump table generation:
27128 The labels need not be in order, and the starting number need not be one
27129 or zero, the case labels are in numerical sequence or not too many case
27130 labels are missing.
27136 switch(i) {\SpecialChar ~
27167 case 4: ...\SpecialChar ~
27199 case 5: ...\SpecialChar ~
27231 case 3: ...\SpecialChar ~
27262 case 6: ...\SpecialChar ~
27294 case 7: ...\SpecialChar ~
27326 case 8: ...\SpecialChar ~
27358 case 9: ...\SpecialChar ~
27390 case 10: ...\SpecialChar ~
27421 case 11: ...\SpecialChar ~
27488 Both the above switch statements will be implemented using a jump-table.
27489 The example to the right side is slightly more efficient as the check for
27490 the lower boundary of the jump-table is not needed.
27494 The number of case labels is not larger than supported by the target architectur
27498 If the case labels are not in numerical sequence ('gaps' between cases)
27499 SDCC checks whether a jump table with additionally inserted dummy cases
27500 is still attractive.
27504 If the starting number is not zero and a check for the lower boundary of
27505 the jump-table can thus be eliminated SDCC might insert dummy cases 0,
27510 Switch statements which have large gaps in the numeric sequence or those
27511 that have too many case labels can be split into more than one switch statement
27512 for efficient code generation, e.g.:
27592 If the above switch statement is broken down into two switch statements
27682 then both the switch statements will be implemented using jump-tables whereas
27683 the unmodified switch statement will not be.
27686 There might be reasons which SDCC cannot know about to either favour or
27687 not favour jump tables.
27688 If the target system has to be as quick for the last switch case as for
27689 the first (pro jump table), or if the switch argument is known to be zero
27690 in the majority of the cases (contra jump table).
27693 The pragma nojtbound
27694 \begin_inset LatexCommand \index{\#pragma nojtbound}
27698 can be used to turn off checking the
27711 It has no effect if a default label is supplied.
27712 Use of this pragma is dangerous: if the switch
27713 \begin_inset LatexCommand \index{switch statement}
27717 argument is not matched by a case statement the processor will happily
27721 Bit-shifting Operations
27722 \begin_inset LatexCommand \index{Bit shifting}
27729 Bit shifting is one of the most frequently used operation in embedded programmin
27731 SDCC tries to implement bit-shift operations in the most efficient way
27747 generates the following code:
27764 In general SDCC will never setup a loop if the shift count is known.
27807 \begin_inset LatexCommand \index{Bit rotation}
27814 A special case of the bit-shift operation is bit rotation
27815 \begin_inset LatexCommand \index{rotating bits}
27819 , SDCC recognizes the following expression to be a left bit-rotation:
27829 char i;\SpecialChar ~
27840 /* unsigned is needed for rotation */
27845 i = ((i << 1) | (i >> 7));
27854 will generate the following code:
27873 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
27874 ns of this case will also be recognized as bit-rotation, i.e.:
27879 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
27882 Nibble and Byte Swapping
27885 Other special cases of the bit-shift operations are nibble or byte swapping
27886 \begin_inset LatexCommand \index{swapping nibbles/bytes}
27890 , SDCC recognizes the following expressions:
27913 i = ((i << 4) | (i >> 4));
27919 j = ((j << 8) | (j >> 8));
27922 and generates a swap instruction for the nibble swapping
27923 \begin_inset LatexCommand \index{Nibble swapping}
27927 or move instructions for the byte swapping
27928 \begin_inset LatexCommand \index{Byte swapping}
27934 \begin_inset Quotes sld
27938 \begin_inset Quotes srd
27941 example can be used to convert from little to big-endian or vice versa.
27942 If you want to change the endianness of a
27946 integer you have to cast to
27953 Note that SDCC stores numbers in little-endian
27959 Usually 8-bit processors don't care much about endianness.
27960 This is not the case for the standard 8051 which only has an instruction
27966 \begin_inset LatexCommand \index{DPTR}
27974 so little-endian is the more efficient byte order.
27978 \begin_inset LatexCommand \index{little-endian}
27983 \begin_inset LatexCommand \index{Endianness}
27988 lowest order first).
27992 \begin_inset LatexCommand \index{Highest Order Bit}
27997 \begin_inset LatexCommand \index{Any Order Bit}
28004 It is frequently required to obtain the highest order bit of an integral
28005 type (long, int, short or char types).
28006 Also obtaining any other order bit is not uncommon.
28007 SDCC recognizes the following expressions to yield the highest order bit
28008 and generates optimized code for it, e.g.:
28021 unsigned char hob1, aob1;
28025 bit hob2, hob3, aob2, aob3;
28034 hob1 = (gint >> 15) & 1;
28038 hob2 = (gint >> 15) & 1;
28042 hob3 = gint & 0x8000;
28046 aob1 = (gint >> 9) & 1;
28050 aob2 = (gint >> 8) & 1;
28054 aob3 = gint & 0x0800;
28064 will generate the following code:
28097 000A E5*01\SpecialChar ~
28124 000C 23\SpecialChar ~
28155 000D 54 01\SpecialChar ~
28182 000F F5*02\SpecialChar ~
28237 0011 E5*01\SpecialChar ~
28264 0013 33\SpecialChar ~
28294 0014 92*00\SpecialChar ~
28349 0016 E5*01\SpecialChar ~
28376 0018 33\SpecialChar ~
28406 0019 92*01\SpecialChar ~
28461 001B E5*01\SpecialChar ~
28488 001D 03\SpecialChar ~
28519 001E 54 01\SpecialChar ~
28546 0020 F5*03\SpecialChar ~
28601 0022 E5*01\SpecialChar ~
28628 0024 13\SpecialChar ~
28658 0025 92*02\SpecialChar ~
28713 0027 E5*01\SpecialChar ~
28740 0029 A2 E3\SpecialChar ~
28767 002B 92*03\SpecialChar ~
28795 Other variations of these cases however will
28800 They are standard C expressions, so I heartily recommend these be the only
28801 way to get the highest order bit, (it is portable).
28802 Of course it will be recognized even if it is embedded in other expressions,
28808 xyz = gint + ((gint >> 15) & 1);
28811 will still be recognized.
28815 \begin_inset LatexCommand \index{Higher Order Byte}
28819 / Higher Order Word
28820 \begin_inset LatexCommand \index{Higher Order Word}
28827 It is also frequently required to obtain a higher order byte or word of
28828 a larger integral type (long, int or short types).
28829 SDCC recognizes the following expressions to yield the higher order byte
28830 or word and generates optimized code for it, e.g.:
28837 unsigned long int glong;
28845 unsigned char hob1, hob2;
28849 unsigned int how1, how2;
28858 hob1 = (gint >> 8) & 0xFF;
28862 hob2 = glong >> 24;
28866 how1 = (glong >> 16) & 0xFFFF;
28880 will generate the following code:
28913 0037 85*01*06\SpecialChar ~
28935 _foo_hob1_1_1,(_gint + 1)
28965 003A 85*05*07\SpecialChar ~
28987 _foo_hob2_1_1,(_glong + 3)
29017 003D 85*04*08\SpecialChar ~
29039 _foo_how1_1_1,(_glong + 2)
29041 0040 85*05*09\SpecialChar ~
29063 (_foo_how1_1_1 + 1),(_glong + 3)
29065 0043 85*03*0A\SpecialChar ~
29087 _foo_how2_1_1,(_glong + 1)
29089 0046 85*04*0B\SpecialChar ~
29111 (_foo_how2_1_1 + 1),(_glong + 2)
29114 Again, variations of these cases may
29119 They are standard C expressions, so I heartily recommend these be the only
29120 way to get the higher order byte/word, (it is portable).
29121 Of course it will be recognized even if it is embedded in other expressions,
29127 xyz = gint + ((gint >> 8) & 0xFF);
29130 will still be recognized.
29134 \begin_inset LatexCommand \label{sub:Peephole-Optimizer}
29139 \begin_inset LatexCommand \index{Peephole optimizer}
29146 The compiler uses a rule based, pattern matching and re-writing mechanism
29147 for peep-hole optimization.
29152 a peep-hole optimizer by Christopher W.
29153 Fraser (cwfraser\SpecialChar ~
29156 A default set of rules are compiled into the compiler, additional rules
29157 may be added with the
29170 \begin_inset LatexCommand \index{-\/-peep-file}
29177 The rule language is best illustrated with examples.
29201 The above rule will change the following assembly
29202 \begin_inset LatexCommand \index{Assembler routines}
29224 Note: All occurrences of a
29228 (pattern variable) must denote the same string.
29229 With the above rule, the assembly sequence:
29239 will remain unmodified.
29243 Other special case optimizations may be added by the user (via
29259 some variants of the 8051 MCU
29260 \begin_inset LatexCommand \index{MCS51 variants}
29273 The following two rules will change all
29292 replace { lcall %1 } by { acall %1 }
29294 replace { ljmp %1 } by { ajmp %1 }
29299 inline-assembler code
29301 is also passed through the peep hole optimizer, thus the peephole optimizer
29302 can also be used as an assembly level macro expander.
29303 The rules themselves are MCU dependent whereas the rule language infra-structur
29304 e is MCU independent.
29305 Peephole optimization rules for other MCU can be easily programmed using
29310 The syntax for a rule is as follows:
29315 rule := replace [ restart ] '{' <assembly sequence> '
29353 <assembly sequence> '
29371 '}' [if <functionName> ] '
29376 <assembly sequence> := assembly instruction (each instruction including
29377 labels must be on a separate line).
29381 The optimizer will apply to the rules one by one from the top in the sequence
29382 of their appearance, it will terminate when all rules are exhausted.
29383 If the 'restart' option is specified, then the optimizer will start matching
29384 the rules again from the top, this option for a rule is expensive (performance)
29385 , it is intended to be used in situations where a transformation will trigger
29386 the same rule again.
29387 An example of this (not a good one, it has side effects) is the following
29410 Note that the replace pattern cannot be a blank, but can be a comment line.
29411 Without the 'restart' option only the innermost 'pop' 'push' pair would
29412 be eliminated, i.e.:
29442 the restart option the rule will be applied again to the resulting code
29443 and then all the pop-push pairs will be eliminated to yield:
29453 A conditional function can be attached to a rule.
29454 Attaching rules are somewhat more involved, let me illustrate this with
29481 The optimizer does a look-up of a function name table defined in function
29486 in the source file SDCCpeeph.c, with the name
29491 If it finds a corresponding entry the function is called.
29492 Note there can be no parameters specified for these functions, in this
29497 is crucial, since the function
29501 expects to find the label in that particular variable (the hash table containin
29502 g the variable bindings is passed as a parameter).
29503 If you want to code more such functions, take a close look at the function
29504 labelInRange and the calling mechanism in source file SDCCpeeph.c.
29505 Currently implemented are
29507 labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
29508 24bitMode, portIsDS390, 24bitModeAndPortDS390
29517 I know this whole thing is a little kludgey, but maybe some day we will
29518 have some better means.
29519 If you are looking at this file, you will see the default rules that are
29520 compiled into the compiler, you can add your own rules in the default set
29521 there if you get tired of specifying the -
29535 \begin_inset LatexCommand \index{ANSI-compliance}
29540 \begin_inset LatexCommand \label{sub:ANSI-Compliance}
29547 The latest publically available version of the standard
29549 ISO/IEC 9899 - Programming languages - C
29551 should be available at:
29552 \begin_inset LatexCommand \url{http://www.open-std.org/jtc1/sc22/wg14/www/standards.html#9899}
29561 Deviations from the compliance:
29564 functions are not reentrant
29565 \begin_inset LatexCommand \index{reentrant}
29569 unless explicitly declared as such or the
29582 \begin_inset LatexCommand \index{-\/-stack-auto}
29588 command line option is specified.
29592 \begin_inset LatexCommand \index{struct}
29597 \begin_inset LatexCommand \index{union}
29601 cannot be assigned values directly, cannot be passed as function parameters
29602 or assigned to each other and cannot be a return value
29603 \begin_inset LatexCommand \index{return value}
29607 from a function, e.g.:
29633 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
29652 s parms) /* invalid in SDCC although allowed in ANSI */
29673 return rets; /* is invalid in SDCC although allowed in ANSI */
29679 initialization of structure arrays must be fully braced.
29685 struct s { char x } a[] = {1, 2};\SpecialChar ~
29690 /* invalid in SDCC */
29692 struct s { char x } a[] = {{1}, {2}}; /* OK */
29697 \begin_inset LatexCommand \index{long long (not supported)}
29702 \begin_inset LatexCommand \index{int (64 bit) (not supported)}
29710 \begin_inset LatexCommand \index{double (not supported)}
29714 ' precision floating point
29715 \begin_inset LatexCommand \index{Floating point support}
29723 \begin_inset LatexCommand \index{K\&R style}
29727 function declarations are NOT allowed.
29733 foo(i,j) /* this old style of function declarations */
29735 int i,j; /* are valid in ANSI but not valid in SDCC */
29750 Most enhancements in C99 are not supported, f.e.:
29758 \begin_inset LatexCommand \index{inline (not supported)}
29764 int increment (int a) { return a+1; } /* is invalid in SDCC although allowed
29770 can be used as a work around */
29778 i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
29782 Certain words that are valid identifiers in the standard may be reserved
29783 words in SDCC unless the
29796 \begin_inset LatexCommand \index{-\/-std-c89}
29811 \begin_inset LatexCommand \index{-\/-std-c99}
29817 command line options are used.
29818 These may include (depending on the selected processor): 'at', 'banked',
29819 'bit', 'code', 'critical', 'data', 'eeprom', 'far', 'flash', 'idata', 'interrup
29820 t', 'near', 'nonbanked', 'pdata', 'reentrant', 'sbit', 'sfr', 'shadowregs',
29821 'sram', 'using', 'wparam', 'xdata', '_overlay', '_asm', '_endasm', and
29823 Compliant equivalents of these keywords are always available in a form
29824 that begin with two underscores
29825 \begin_inset LatexCommand \index{\_\_ (prefix for extended keywords)}
29830 '__data' instead of 'data'.
29833 Cyclomatic Complexity
29834 \begin_inset LatexCommand \index{Cyclomatic complexity}
29841 Cyclomatic complexity of a function is defined as the number of independent
29842 paths the program can take during execution of the function.
29843 This is an important number since it defines the number test cases you
29844 have to generate to validate the function.
29845 The accepted industry standard for complexity number is 10, if the cyclomatic
29846 complexity reported by SDCC exceeds 10 you should think about simplification
29847 of the function logic.
29848 Note that the complexity level is not related to the number of lines of
29849 code in a function.
29850 Large functions can have low complexity, and small functions can have large
29856 SDCC uses the following formula to compute the complexity:
29861 complexity = (number of edges in control flow graph) - (number of nodes
29862 in control flow graph) + 2;
29866 Having said that the industry standard is 10, you should be aware that in
29867 some cases it be may unavoidable to have a complexity level of less than
29869 For example if you have switch statement with more than 10 case labels,
29870 each case label adds one to the complexity level.
29871 The complexity level is by no means an absolute measure of the algorithmic
29872 complexity of the function, it does however provide a good starting point
29873 for which functions you might look at for further optimization.
29876 Retargetting for other Processors
29879 The issues for retargetting the compiler are far too numerous to be covered
29881 What follows is a brief description of each of the seven phases of the
29882 compiler and its MCU dependency.
29885 Parsing the source and building the annotated parse tree.
29886 This phase is largely MCU independent (except for the language extensions).
29887 Syntax & semantic checks are also done in this phase, along with some initial
29888 optimizations like back patching labels and the pattern matching optimizations
29889 like bit-rotation etc.
29892 The second phase involves generating an intermediate code which can be easy
29893 manipulated during the later phases.
29894 This phase is entirely MCU independent.
29895 The intermediate code generation assumes the target machine has unlimited
29896 number of registers, and designates them with the name iTemp.
29897 The compiler can be made to dump a human readable form of the code generated
29911 This phase does the bulk of the standard optimizations and is also MCU independe
29913 This phase can be broken down into several sub-phases:
29917 Break down intermediate code (iCode) into basic blocks.
29919 Do control flow & data flow analysis on the basic blocks.
29921 Do local common subexpression elimination, then global subexpression elimination
29923 Dead code elimination
29927 If loop optimizations caused any changes then do 'global subexpression eliminati
29928 on' and 'dead code elimination' again.
29931 This phase determines the live-ranges; by live range I mean those iTemp
29932 variables defined by the compiler that still survive after all the optimization
29934 Live range analysis
29935 \begin_inset LatexCommand \index{Live range analysis}
29939 is essential for register allocation, since these computation determines
29940 which of these iTemps will be assigned to registers, and for how long.
29943 Phase five is register allocation.
29944 There are two parts to this process.
29948 The first part I call 'register packing' (for lack of a better term).
29949 In this case several MCU specific expression folding is done to reduce
29954 The second part is more MCU independent and deals with allocating registers
29955 to the remaining live ranges.
29956 A lot of MCU specific code does creep into this phase because of the limited
29957 number of index registers available in the 8051.
29960 The Code generation phase is (unhappily), entirely MCU dependent and very
29961 little (if any at all) of this code can be reused for other MCU.
29962 However the scheme for allocating a homogenized assembler operand for each
29963 iCode operand may be reused.
29966 As mentioned in the optimization section the peep-hole optimizer is rule
29967 based system, which can reprogrammed for other MCUs.
29970 More information is available in a wiki
29971 \begin_inset LatexCommand \index{wiki}
29976 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/release_wiki/index.php?page=SDCC+internals+and+porting}
29980 ) and in the thread
29981 \begin_inset LatexCommand \url{http://sf.net/mailarchive/message.php?msg_id=13954144}
29989 \begin_inset LatexCommand \index{Compiler internals}
29996 The anatomy of the compiler
29997 \begin_inset LatexCommand \label{sub:The-anatomy-of}
30006 This is an excerpt from an article published in Circuit Cellar Magazine
30012 It's a little outdated (the compiler is much more efficient now and user/develo
30013 per friendly), but pretty well exposes the guts of it all.
30019 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
30020 It is fairly easy to retarget for other 8-bit MCU.
30021 Here we take a look at some of the internals of the compiler.
30026 \begin_inset LatexCommand \index{Parsing}
30033 Parsing the input source file and creating an AST (Annotated Syntax Tree
30034 \begin_inset LatexCommand \index{Annotated syntax tree}
30039 This phase also involves propagating types (annotating each node of the
30040 parse tree with type information) and semantic analysis.
30041 There are some MCU specific parsing rules.
30042 For example the storage classes, the extended storage classes are MCU specific
30043 while there may be a xdata storage class for 8051 there is no such storage
30044 class for z80 or Atmel AVR.
30045 SDCC allows MCU specific storage class extensions, i.e.
30046 xdata will be treated as a storage class specifier when parsing 8051 C
30047 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
30052 \begin_inset LatexCommand \index{iCode}
30059 Intermediate code generation.
30060 In this phase the AST is broken down into three-operand form (iCode).
30061 These three operand forms are represented as doubly linked lists.
30062 ICode is the term given to the intermediate form generated by the compiler.
30063 ICode example section shows some examples of iCode generated for some simple
30064 C source functions.
30068 \begin_inset LatexCommand \index{Optimizations}
30075 Bulk of the target independent optimizations is performed in this phase.
30076 The optimizations include constant propagation, common sub-expression eliminati
30077 on, loop invariant code movement, strength reduction of loop induction variables
30078 and dead-code elimination.
30081 Live range analysis
30082 \begin_inset LatexCommand \index{Live range analysis}
30089 During intermediate code generation phase, the compiler assumes the target
30090 machine has infinite number of registers and generates a lot of temporary
30092 The live range computation determines the lifetime of each of these compiler-ge
30093 nerated temporaries.
30094 A picture speaks a thousand words.
30095 ICode example sections show the live range annotations for each of the
30097 It is important to note here, each iCode is assigned a number in the order
30098 of its execution in the function.
30099 The live ranges are computed in terms of these numbers.
30100 The from number is the number of the iCode which first defines the operand
30101 and the to number signifies the iCode which uses this operand last.
30104 Register Allocation
30105 \begin_inset LatexCommand \index{Register allocation}
30112 The register allocation determines the type and number of registers needed
30114 In most MCUs only a few registers can be used for indirect addressing.
30115 In case of 8051 for example the registers R0 & R1 can be used to indirectly
30116 address the internal ram and DPTR to indirectly address the external ram.
30117 The compiler will try to allocate the appropriate register to pointer variables
30119 ICode example section shows the operands annotated with the registers assigned
30121 The compiler will try to keep operands in registers as much as possible;
30122 there are several schemes the compiler uses to do achieve this.
30123 When the compiler runs out of registers the compiler will check to see
30124 if there are any live operands which is not used or defined in the current
30125 basic block being processed, if there are any found then it will push that
30126 operand and use the registers in this block, the operand will then be popped
30127 at the end of the basic block.
30131 There are other MCU specific considerations in this phase.
30132 Some MCUs have an accumulator; very short-lived operands could be assigned
30133 to the accumulator instead of a general-purpose register.
30139 Figure II gives a table of iCode
30140 \begin_inset LatexCommand \index{iCode}
30144 operations supported by the compiler.
30145 The code generation involves translating these operations into corresponding
30146 assembly code for the processor.
30147 This sounds overly simple but that is the essence of code generation.
30148 Some of the iCode operations are generated on a MCU specific manner for
30149 example, the z80 port does not use registers to pass parameters so the
30150 SEND and RECV iCode operations will not be generated, and it also does
30151 not support JUMPTABLES.
30160 \begin_inset Tabular
30161 <lyxtabular version="3" rows="39" columns="4">
30162 <features islongtable="true" headBottomDL="true">
30163 <column alignment="block" valignment="top" leftline="true" width="13col%">
30164 <column alignment="left" valignment="top" leftline="true" width="13col%">
30165 <column alignment="block" valignment="top" leftline="true" width="22col%">
30166 <column alignment="block" valignment="top" leftline="true" rightline="true" width="40col%">
30167 <row topline="true" bottomline="true" endhead="true">
30168 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30178 \begin_inset LatexCommand \index{iCode}
30185 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30195 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30205 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30216 <row topline="true">
30217 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30227 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30234 IC_LEFT() IC_RESULT()
30237 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30247 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30254 IC_RESULT = ! IC_LEFT;
30258 <row topline="true">
30259 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30269 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30276 IC_LEFT() IC_RESULT()
30279 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30286 Bitwise complement of
30289 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30296 IC_RESULT = ~IC_LEFT;
30300 <row topline="true">
30301 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30311 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30318 IC_LEFT() IC_RESULT()
30321 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30328 Rotate right with carry
30331 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30338 IC_RESULT = (IC_LEFT << 1) | (IC_LEFT >> (sizeof(IC_LEFT)*8-1));
30342 <row topline="true">
30343 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30353 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30360 IC_LEFT() IC_RESULT()
30363 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30370 Rotate left with carry
30373 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30380 IC_RESULT = (IC_LEFT << (sizeof(LC_LEFT)*8-1) ) | (IC_LEFT >> 1);
30384 <row topline="true">
30385 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30395 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30402 IC_LEFT() IC_RESULT()
30405 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30412 Get the highest order bit of IC_LEFT
30415 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30422 IC_RESULT = (IC_LEFT >> (sizeof(IC_LEFT)*8 -1));
30426 <row topline="true">
30427 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30437 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30444 IC_LEFT() IC_RESULT()
30447 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30457 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30464 IC_RESULT = - IC_LEFT;
30468 <row topline="true">
30469 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30479 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30489 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30496 Push the operand into stack
30499 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30510 <row topline="true">
30511 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30521 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30531 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30538 Pop the operand from the stack
30541 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30552 <row topline="true">
30553 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30563 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30570 IC_LEFT() IC_RESULT()
30573 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30580 Call the function represented by IC_LEFT
30583 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30590 IC_RESULT = IC_LEFT();
30594 <row topline="true">
30595 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30605 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30612 IC_LEFT() IC_RESULT()
30615 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30622 Call via function pointer
30625 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30632 IC_RESULT = (*IC_LEFT)();
30636 <row topline="true">
30637 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30647 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30657 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30664 Return the value in operand IC_LEFT
30667 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30678 <row topline="true">
30679 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30689 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30699 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30709 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30720 <row topline="true">
30721 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30731 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30741 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30751 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30762 <row topline="true">
30763 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30773 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30780 IC_LEFT() IC_RIGHT() IC_RESULT()
30783 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30793 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30800 IC_RESULT = IC_LEFT + IC_RIGHT
30804 <row topline="true">
30805 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30815 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30822 IC_LEFT() IC_RIGHT() IC_RESULT()
30825 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30835 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30842 IC_RESULT = IC_LEFT - IC_RIGHT
30846 <row topline="true">
30847 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30857 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30864 IC_LEFT() IC_RIGHT() IC_RESULT()
30867 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30877 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30884 IC_RESULT = IC_LEFT * IC_RIGHT;
30888 <row topline="true">
30889 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30899 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30906 IC_LEFT() IC_RIGHT() IC_RESULT()
30909 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30919 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30926 IC_RESULT = IC_LEFT / IC_RIGHT;
30930 <row topline="true">
30931 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30941 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30948 IC_LEFT() IC_RIGHT() IC_RESULT()
30951 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30961 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
30968 IC_RESULT = IC_LEFT % IC_RIGHT;
30972 <row topline="true">
30973 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30983 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
30990 IC_LEFT() IC_RIGHT() IC_RESULT()
30993 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31003 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31010 IC_RESULT = IC_LEFT < IC_RIGHT;
31014 <row topline="true">
31015 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31025 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31032 IC_LEFT() IC_RIGHT() IC_RESULT()
31035 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31045 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31052 IC_RESULT = IC_LEFT > IC_RIGHT;
31056 <row topline="true">
31057 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31067 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31074 IC_LEFT() IC_RIGHT() IC_RESULT()
31077 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31087 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31094 IC_RESULT = IC_LEFT == IC_RIGHT;
31098 <row topline="true">
31099 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31109 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31116 IC_LEFT() IC_RIGHT() IC_RESULT()
31119 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31126 Logical and operation
31129 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31136 IC_RESULT = IC_LEFT && IC_RIGHT;
31140 <row topline="true">
31141 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31151 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31158 IC_LEFT() IC_RIGHT() IC_RESULT()
31161 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31168 Logical or operation
31171 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31178 IC_RESULT = IC_LEFT || IC_RIGHT;
31182 <row topline="true">
31183 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31193 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31200 IC_LEFT() IC_RIGHT() IC_RESULT()
31203 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31213 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31220 IC_RESULT = IC_LEFT ^ IC_RIGHT;
31224 <row topline="true">
31225 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31235 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31242 IC_LEFT() IC_RIGHT() IC_RESULT()
31245 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31255 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31262 IC_RESULT = IC_LEFT | IC_RIGHT;
31266 <row topline="true">
31267 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31277 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31284 IC_LEFT() IC_RIGHT() IC_RESULT()
31287 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31297 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31304 IC_RESULT = IC_LEFT & IC_RIGHT;
31308 <row topline="true">
31309 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31319 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31326 IC_LEFT() IC_RIGHT() IC_RESULT()
31329 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31339 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31346 IC_RESULT = IC_LEFT << IC_RIGHT
31350 <row topline="true">
31351 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31361 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31368 IC_LEFT() IC_RIGHT() IC_RESULT()
31371 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31381 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31388 IC_RESULT = IC_LEFT >> IC_RIGHT
31392 <row topline="true">
31393 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31405 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31412 IC_LEFT() IC_RESULT()
31415 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31425 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31432 IC_RESULT = (*IC_LEFT);
31436 <row topline="true">
31437 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31447 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31454 IC_RIGHT() IC_RESULT()
31457 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31467 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31474 (*IC_RESULT) = IC_RIGHT;
31478 <row topline="true">
31479 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31489 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31496 IC_RIGHT() IC_RESULT()
31499 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31509 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31516 IC_RESULT = IC_RIGHT;
31520 <row topline="true">
31521 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31531 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31538 IC_COND IC_TRUE IC_LABEL
31541 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31549 If true label is present then jump to true label if condition is true else
31550 jump to false label if condition is false
31553 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31560 if (IC_COND) goto IC_TRUE;
31566 If (!IC_COND) goto IC_FALSE;
31570 <row topline="true">
31571 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31581 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31588 IC_LEFT() IC_RESULT()
31591 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31601 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31608 IC_RESULT = &IC_LEFT();
31612 <row topline="true">
31613 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31623 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31630 IC_JTCOND IC_JTLABELS
31633 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31640 Jump to list of labels depending on the value of JTCOND
31643 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31654 <row topline="true">
31655 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31665 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31672 IC_RIGHT() IC_LEFT() IC_RESULT()
31675 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31685 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31692 IC_RESULT = (typeof IC_LEFT) IC_RIGHT;
31696 <row topline="true">
31697 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31707 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31717 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31724 This is used for passing parameters in registers;
31726 move IC_LEFT to the next available parameter register.
31729 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31740 <row topline="true">
31741 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31751 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31761 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31768 This is used for receiving parameters passed in registers;
31770 Move the values in the next parameter register to IC_RESULT
31773 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31784 <row topline="true" bottomline="true">
31785 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31793 (some more have been added)
31796 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31803 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
31810 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
31836 In the original article Figure II was announced to be downloadable on
31841 ftp://ftp.circuitcellar.com/pub/Circuit_Cellar/2000/121/dutta.ZIP
31845 \begin_inset LatexCommand \index{iCode}
31852 This section shows some details of iCode.
31853 The example C code does not do anything useful; it is used as an example
31854 to illustrate the intermediate code generated by the compiler.
31866 /* This function does nothing useful.
31873 for the purpose of explaining iCode */
31876 short function (data int *x)
31884 short i=10; \SpecialChar ~
31886 /* dead initialization eliminated */
31891 short sum=10; /* dead initialization eliminated */
31904 while (*x) *x++ = *p++;
31918 /* compiler detects i,j to be induction variables */
31922 for (i = 0, j = 10 ; i < 10 ; i++, j
31948 mul += i * 3; \SpecialChar ~
31950 /* this multiplication remains */
31956 gint += j * 3;\SpecialChar ~
31958 /* this multiplication changed to addition */
31972 In addition to the operands each iCode contains information about the filename
31973 and line it corresponds to in the source file.
31974 The first field in the listing should be interpreted as follows:
31979 Filename(linenumber: iCode Execution sequence number : ICode hash table
31980 key : loop depth of the iCode).
31985 Then follows the human readable form of the ICode operation.
31986 Each operand of this triplet form can be of three basic types a) compiler
31987 generated temporary b) user defined variable c) a constant value.
31988 Note that local variables and parameters are replaced by compiler generated
31991 \begin_inset LatexCommand \index{Live range analysis}
31995 are computed only for temporaries (i.e.
31996 live ranges are not computed for global variables).
31998 \begin_inset LatexCommand \index{Register allocation}
32002 are allocated for temporaries only.
32003 Operands are formatted in the following manner:
32008 Operand Name [lr live-from : live-to ] { type information } [ registers
32014 As mentioned earlier the live ranges are computed in terms of the execution
32015 sequence number of the iCodes, for example
32017 the iTemp0 is live from (i.e.
32018 first defined in iCode with execution sequence number 3, and is last used
32019 in the iCode with sequence number 5).
32020 For induction variables such as iTemp21 the live range computation extends
32021 the lifetime from the start to the end of the loop.
32023 The register allocator used the live range information to allocate registers,
32024 the same registers may be used for different temporaries if their live
32025 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
32026 iTemp17 since their live ranges do not overlap.
32027 In addition the allocator also takes into consideration the type and usage
32028 of a temporary, for example itemp6 is a pointer to near space and is used
32029 as to fetch data from (i.e.
32030 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
32031 Some short lived temporaries are allocated to special registers which have
32032 meaning to the code generator e.g.
32033 iTemp13 is allocated to a pseudo register CC which tells the back end that
32034 the temporary is used only for a conditional jump the code generation makes
32035 use of this information to optimize a compare and jump ICode.
32037 There are several loop optimizations
32038 \begin_inset LatexCommand \index{Loop optimization}
32042 performed by the compiler.
32043 It can detect induction variables iTemp21(i) and iTemp23(j).
32044 Also note the compiler does selective strength reduction
32045 \begin_inset LatexCommand \index{Strength reduction}
32050 the multiplication of an induction variable in line 18 (gint = j * 3) is
32051 changed to addition, a new temporary iTemp17 is allocated and assigned
32052 a initial value, a constant 3 is then added for each iteration of the loop.
32053 The compiler does not change the multiplication
32054 \begin_inset LatexCommand \index{Multiplication}
32058 in line 17 however since the processor does support an 8 * 8 bit multiplication.
32060 Note the dead code elimination
32061 \begin_inset LatexCommand \index{Dead-code elimination}
32065 optimization eliminated the dead assignments in line 7 & 8 to I and sum
32073 Sample.c (5:1:0:0) _entry($9) :
32078 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
32083 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
32088 Sample.c(11:4:53:0) preHeaderLbl0($11) :
32093 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
32099 Sample.c(11:6:5:1) _whilecontinue_0($1) :
32104 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
32110 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
32115 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
32121 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
32127 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
32133 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
32139 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
32140 * int}[r0] + 0x2 {short}
32145 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
32150 Sample.c(11:17:21:0)_whilebreak_0($3) :
32155 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
32160 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
32165 Sample.c(15:20:54:0)preHeaderLbl1($13) :
32170 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
32175 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
32180 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
32185 Sample.c(15:24:26:1)_forcond_0($4) :
32190 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
32196 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
32201 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
32202 + ITemp21 [lr21:38]{short}[r4]
32207 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
32213 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
32214 + iTemp15 [lr29:30]{short}[r1]
32219 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
32225 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
32231 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
32237 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
32243 Sample.c(19:38:47:1) goto _forcond_0($4)
32248 Sample.c(19:39:48:0)_forbreak_0($7) :
32253 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
32254 + ITemp11 [lr19:40]{short}[r3]
32259 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
32264 Sample.c(20:42:51:0)_return($8) :
32269 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
32275 Finally the code generated for this function:
32316 ; ----------------------------------------------
32321 ; function function
32326 ; ----------------------------------------------
32336 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
32348 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
32360 ;_whilecontinue_0($1) :
32370 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
32375 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
32434 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
32453 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
32500 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
32540 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
32566 ; iTemp6 [lr5:16]{_near * int}[r0] =
32571 ; iTemp6 [lr5:16]{_near * int}[r0] +
32588 ; goto _whilecontinue_0($1)
32600 ; _whilebreak_0($3) :
32610 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
32622 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
32634 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
32646 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
32665 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
32694 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
32699 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
32744 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
32749 ; iTemp21 [lr21:38]{short}[r4]
32775 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
32808 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
32813 ; iTemp15 [lr29:30]{short}[r1]
32832 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
32879 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
32926 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
32938 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
32952 cjne r5,#0xff,00104$
32964 ; goto _forcond_0($4)
32976 ; _forbreak_0($7) :
32986 ; ret iTemp24 [lr40:41]{short}
33029 A few words about basic block successors, predecessors and dominators
33032 Successors are basic blocks
33033 \begin_inset LatexCommand \index{Basic blocks}
33037 that might execute after this basic block.
33039 Predecessors are basic blocks that might execute before reaching this basic
33042 Dominators are basic blocks that WILL execute before reaching this basic
33076 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
33079 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
33082 c) domVect of [BB4] = BB1 ...
33083 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
33091 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
33101 Thanks to all the other volunteer developers who have helped with coding,
33102 testing, web-page creation, distribution sets, etc.
33103 You know who you are :-)
33111 Also thanks to Sourceforge
33112 \begin_inset LatexCommand \url{http://www.sf.net}
33116 which has hosted the project since 1999 and donates significant download
33117 bandwidth and probably more than
33125 CPU cycles per day.
33133 more than 10^13 is an estimate: on my Athlon 2800+ it takes about (0.5+6.5+20)
33134 minutes for (configure+make+regression test), and there is (i386, amd64,
33135 alpha, ppc64, (mingw32), sparc, macosx).
33142 This document was initially written by Sandeep Dutta
33145 All product names mentioned herein may be trademarks
33146 \begin_inset LatexCommand \index{Trademarks}
33150 of their respective companies.
33157 To avoid confusion, the installation and building options for SDCC itself
33158 (chapter 2) are not part of the index.
33162 \begin_inset LatexCommand \printindex{}