SDCC - Small Device C Compiler

What is SDCC?

SDCC is a retargettable, optimizing ANSI - C compiler suite that targets the Intel MCS51 based microprocessors (8031, 8032, 8051, 8052, etc.), Maxim (formerly Dallas) DS80C390 variants, Freescale (formerly Motorola) HC08 based (hc08, s08) and Zilog Z80 based MCUs (z80, z180, gbz80, Rabbit 2000/3000, Rabbit 3000A). Work is in progress on supporting the Microchip PIC16 and PIC18 targets. It can be retargeted for other microprocessors.

SDCC suite is a collection of several components derived from different sources with different FOSS licenses. SDCC compiler suite include:

  • sdas and sdld, a retargettable assembler and linker, based on ASXXXX, written by Alan Baldwin; (GPL).
  • sdcpp preprocessor, based on GCC cpp; (GPL).
  • ucsim simulators, originally written by Daniel Drotos; (GPL).
  • sdcdb source level debugger, originally written by Sandeep Dutta; (GPL).
  • sdbinutils library archive utilities, including sdar, sdranlib and sdnm, derived from GNU Binutils; (GPL)
  • SDCC run-time libraries; (GPL+LE). Pic device libraries and header files are derived from Microchip header (.inc) and linker script (.lkr) files. Microchip requires that "The header files should state that they are only to be used with authentic Microchip devices" which makes them incompatible with the GPL.
  • gcc-test regression tests, derived from gcc-testsuite; (no license explicitely specified, but since it is a part of GCC is probably GPL licensed)
  • packihx; (public domain)
  • makebin; (zlib/libpng License)
  • sdcc C compiler, originally written by Sandeep Dutta; (GPL). Some of the features include:
    • extensive MCU specific language extensions, allowing effective use of the underlying hardware.
    • a host of standard optimizations such as global sub expression elimination, loop optimizations (loop invariant, strength reduction of induction variables and loop reversing), constant folding and propagation, copy propagation, dead code elimination and jump tables for 'switch' statements.
    • MCU specific optimizations, including a global register allocator.
    • adaptable MCU specific backend that should be well suited for other 8 bit MCUs
    • independent rule based peep hole optimizer.
    • a full range of data types: char (8 bits, 1 byte), short (16 bits, 2 bytes), int (16 bits, 2 bytes), long (32 bit, 4 bytes), float (4 byte IEEE) and _Bool/bool;
      basic (no integer constants) support for long long (64 bit, 8 bytes) data types for the z80, z180, r2k, r3ka, gbz80, hc08 and s08 targets.
    • the ability to add inline assembler code anywhere in a function.
    • the ability to report on the complexity of a function to help decide what should be re-written in assembler.
    • a good selection of automated regression tests.

SDCC was written by Sandeep Dutta and released under a GPL license. Since its initial release there have been numerous bug fixes and improvements. As of December 1999, the code was moved to SourceForge where all the "users turned developers" can access the same source tree. SDCC is constantly being updated with all the users' and developers' input.


July 9th, 2012: Small Device C Compiler 3.2.0 released.

A new release of SDCC, the portable optimizing compiler for 8051, DS390, Z80, Z180, Rabbit 2000, HC08 and PIC microprocessors is now available ( Sources, documentation and binaries compiled for x86 Linux, x86 MS Windows and PPC Mac OS X are available.

SDCC 3.2.0 Feature List:

  • Named address spaces with optimal placement of bank selection calls.
  • _Noreturn.
  • --std-c11 command line option for ISO C11.
  • ucsim support for the LR35902 (gameboy CPU).
  • The gbz80 port is alive again, there were many bug fixes and the generated code is much better now.
  • Pic 14 enhanced core libraries are included in sdcc builds by default
  • Added pic 14 enhanced core devices: 16f1503, 16f1508, 16f1509, 16f1516, 16f1517, 16f1518, 16f1519, 16f1526, 16f1527, 16f1946, 16f1947
  • PIC14/PIC16: Implemented __critical; PIC14 __critical function cannot have arguments for now, though
  • inclusion of some tests from the gcc test suite into the sdcc regression test suite led to many bugs being found and fixed.
  • Many macros with previously non-standard-compliant names have been renamed (SDCC_REVISION to __SDCC_REVISION, etc).
  • setjmp() / longjmp() for the z180 and r2k ports.
  • Added sdar archive managing utility. sdar and sdranlib are derived from GNU binutils package
  • Added support for pic 14 core devices: 16f720, 16f721, 16f882, 16f883, 16f884, 16f747, 16f946
  • sdcpp synchronized with GNU cpp 4.6.3
  • Added support for pic 18f1230/18f1330 device family
  • Implemented #pragma config for pic16 target
  • sdcc now works on Debian GNU/Hurd.
  • New register allocator for the hc08 port, resulting in better code being generated.
  • New s08 port.
  • New r3ka port.
  • Many small improvements in the z80, hc08 and r2k code generation, reducing code size.
  • Shift, multiplication, division and returning of long long are now supported (modulo for long long is still missing, integer literals of type long long are broken).

Numerous feature requests and bug fixes are included as well.

You can download the release from:

What Platforms are Supported?

Linux - x86, Microsoft Windows - x86 and Mac OS X are the primary, so called "officially supported" platforms.

SDCC compiles natively on Linux and Mac OS X using gcc. Windows release and snapshot builds are made by cross compiling to mingw32 on a Linux host.

Windows 9x/NT/2000/XP/Vista/7 users are recommended to use Cygwin ( or may try the unsupported Microsoft Visual C++ build scripts.

Downloading SDCC

See the Sourceforge download page for the last released version including source and binary packages for Linux - x86, Microsoft Windows - x86 and Mac OS X - ppc and i386.

Major Linux distributions take care of SDCC installation packages themselves and you will find SDCC in their repositories. Unfortunately SDCC packages included in Linux disributions are often outdated. In this case users are encouraged to compile the latest official SDCC release or a recent snapshot build by themselves or download the pre-compiled binaries from Sourceforge download page.

SDCC is known to compile from the source code also on the following platforms:

  • Microsoft Windows - x86_64
  • Linux - x86_64
  • Linux - Alpha
  • Linux - IBM Power5
  • NetBSD - i386
  • NetBSD - Sparc64
  • FreeBSD - i386
  • SUN Solaris - i386
  • SUN Solaris - Sparc
  • Rasbian (Debian for Raspberry Pi) - ARMv6

SDCC is always under active development. Please consider downloading one of the snapshot builds if you have run across a bug, or if the above release is more than two months old.

The latest development source code can be accessed using Subversion. The following will fetch the latest sources:

svn co sdcc

... will create the sdcc directory in your current directory and place all downloaded code there. You can browse the Subversion repository here.

SourceForge has further documentation on accessing the Subversion repository here.

Before reporting a bug, please check your SDCC version and build date using the -v option, and be sure to include the full version string in your bug report. For example:

sdcc/bin > sdcc -v
SDCC : mcs51/gbz80/z80/avr/ds390/pic14/TININative/xa51 2.3.8 (Feb 10 2004) (UNIX)

Support for SDCC

SDCC and the included support packages come with fair amounts of documentation and examples. When they aren't enough, you can find help in the places listed below. Here is a short check list of tips to greatly improve your chances of obtaining a helpful response.

  1. Attach the code you are compiling with SDCC. It should compile "out of the box". Snippets must compile and must include any required header files, etc. Incomplete information will hamper your chance of a timely response.
  2. Specify the exact command you use to run SDCC, or attach your Makefile.
  3. Specify the SDCC version (type "sdcc -v"), your platform and operating system.
  4. Provide an exact copy of any error message or incorrect output.

Please attempt to include these 4 important parts, as applicable, in all requests for support or when reporting any problems or bugs with SDCC. Though this will make your message lengthy, it will greatly improve your chance that SDCC users and developers will be able to help you. Some SDCC developers are frustrated by bug reports without code provided that they can use to reproduce and ultimately fix the problem, so please be sure to provide sample code if you are reporting a bug!

  • Web Page - you are (X) here.
  • Mailing list: [use "BUG REPORTING" below if you believe you have found a bug.]
    • Send to the developer list <> - for development work on SDCC
    • Send to the user list <> - [preferred] all developers and all users.
    • Subscribe to the user list
  • Bug Reporting - if you have a problem using SDCC, we need to hear about it. Please attach code to reproduce the problem, and be sure to provide your email address so a developer can contact you if they need more information to investigate and fix the bug.
  • Website/Documentation Issues - Please report erroneous, missing or outdated information
  • SDCC Message Forum - an account on Sourceforge is needed if you're going to post and reply. Short easy online fill-in the blanks.
  • Open Knowledge Web Site - Run by Thorsten Godau <>

Who is SDCC?

  • Sandeep Dutta <> - original author (SDCC's version of Torvalds)
  • Jean Loius-VERN <> - substantial improvement in the back-end code generation.
  • Daniel Drotos <> - Freeware simulator for 8051.
  • Kevin Vigor <> - numerous enhancements and bug fixes to the Dallas ds390 tree.
  • Johan Knol <> - testing and patching ds390 tree, bug stompper extrodanaire
  • Scott Dattalo <> - sdcc for Microchip PIC controller target
  • Karl Bongers <> - mcs51 support, winbin builds, and an occasional bug.
  • Bernhard Held <> - snpshot builds and general housekeeping
  • Frieder Ferlemann <> - contributions to the documentation and last stages of code generation
  • Jesus Calvino-Fraga <> - math functions, AOMF51, linker improvements
  • Borut Ražem <> - WIN32 MSC, cygwin and mingw ports, NSIS installer, preprocessor and front end improvements, bug fixing, snapshot builds on Distibuted Compile Farm, ...
  • Vangelis Rokas <> - PIC16 taget development for Microchip PIC18F microcontrollers
  • Erik Petrich <> - Bug fixes and improvements for the front end, 8051, z80 and hc08
  • Dave Helton <> - website design
  • Paul Stoffregen <> - mcs51 optimizations and website maintenance.
  • Michael Hope <> - initial Z80 target, additional coding and bug fixes.
  • Maarten Brock <> - several bug fixes and improvements, esp. for mcs51 target
  • Raphael Neider <> - bug fixes and optimizations for PIC16, completion of the PIC14 target
  • Philipp Klaus Krause <> - z80 and gbz80 bug fixes and optimizations, z180 target
  • Leland Morrison <> - Rabbit 2000 support: the target code generator, sdasrab assembler and ucsim support
  • Molnár Károly <> - adding pic devices, developing and maintaining pic device files generation scripts

SDCC has had help from a number of external sources, including:

  • Alan Baldwin <> - Initial version of ASXXXX  and  ASLINK.
  • John Hartman <> - Porting ASXXXX and ASLINK for 8051.
  • Dmitry S. Obukhov <> - malloc and serial I/O routines.
  • Pascal Felber - Some of the Z80 related files are borrowed from the Gameboy Development Kit (GBDK).
  • The GCC development team - for GNU C preprocessor, the basis of sdcpp preprocessor and gcc test suite, partially included into the SDCC regression test suite
  • The GNU Binutils development team - for GNU Binutils, the basis of sdbinutils
  • Boost Community - for Boost C++ libraries used in sdcc compiler
  • Timo Bingmann - for STX B+ Tree C++ Template Classes used in sdcc compiler
  • Malini Dutta <> - Sandeep's wife, for her patience and support.

Past news

July 6th, 2012: SDCC 3.2.0 RC4 released.

SDCC 3.2.0 Release Candidate 4 source, doc and binary packages for x86 Linux, 32 bit Windows and universal Mac OS X are available in corresponding folders at:

June 29th, 2012: SDCC 3.2.0 RC3 released.

SDCC 3.2.0 Release Candidate 3 source, doc and binary packages for x86 Linux, 32 bit Windows and universal Mac OS X are available in corresponding folders at:

June 24th, 2012: SDCC 3.2.0 RC2 released.

SDCC 3.2.0 Release Candidate 2 source, doc and binary packages for x86 Linux, 32 bit Windows and universal Mac OS X are available in corresponding folders at:

June 16th, 2012: SDCC 3.2.0 RC1 released.

SDCC 3.2.0 Release Candidate 1 source, doc and binary packages for x86 Linux, 32 bit Windows and universal Mac OS X are available in corresponding folders at:

Previous News

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Last updated:
October 19, 2012 08:34:58.