Raisonance
- Developers of C compilers and other development tools for microcontrollers (such as 8051, ST7, STR7, and STR9 and smart cards. Includes a support sorum.
- http://www.raisonance.com

The Z88 Development Kit
- A C cross compiler for the Z80 CPU with libraries for mainly Z88 but also ZX Spectrum VZ200/300, NC100/200 and other Z80 based computers.
- http://www.z88dk.org

Microchip PICmicro C Compiler
- For Windows and Linux, as well as an integrated development environment and tools. Support all the PIC12, PIC14, PIC16, and PIC18. By CCS, Inc. [Commercial]
- http://www.ccsinfo.com/

Altium, Ltd.
- Makes TASKING brand IDE, compiler, debugger, embedded Internet and RTOS offerings, support wide range of DSP and 8/16/32-bit microprocessors and microcontrollers for all areas of embedded communications.
- http://www.tasking.com/

Cosmic Software
- Provides C cross development tools and services to embedded systems engineers using microcontrollers from Infineon, Motorola and STMicroelectronics. Tools include IDE, ANSI Compilers, Simulators and real-time debuggers.
- http://www.cosmic-software.com/

Chess/Checkers
- A tool-suite that includes a retargetable optimizing compiler, processor simulator, processor instruction set test-program generator. It is automatically targeted to any processor specified in the nML processor modelling language. By Target Compiler Techn
- http://www.retarget.com/products-more.html

HP InfoTech S.R.L.
- Makes CodeVisionAVR C compiler, integrated development environment (IDE), automatic program generator, ChipBlasterAVR in-system programmer, code wizard, for Atmel AVR microcontrollers. [commercial]
- http://www.hpinfotech.ro/

HI-TECH Software
- Produces ANSI C cross compilers and assemblers for a range of embbedded systems. Supported chips include the 8051, 8051XA and PIC.
- http://www.htsoft.com/

XTC-1750A
- C cross-development environment for target systems with MIL-STD-1750A architecture. It includes across compiler, cross assembler, linker/loader, source-level debugger, and target kernel.
- http://www.cleanscape.net/stdprod/xtc1750a/

Official TIGCC Site
- Mainly a C compiler for Texas Instruments TI-89, TI-92 Plus calculators; based on GCC, GNU Compiler Collection.
- http://tigcc.ticalc.org/

Keil Software, Inc.
- Vendor of C compilers and other development tools for the 8051, 251, C16x/ST10 microcontroller families. Has discussion forum, searchable tech support knowledgebase with over 1500 articles.
- http://www.keil.com/

cc65
- C compiler for 6502 based systems; direct library support (startup/initialization code) and support libraries for Commodore C64/C128, C16, C116, Plus/4, 600/700 families of computers, Apple II, Atari 8-bit systems. [Freeware]
- http://www.cc65.org/

Crossware Products
- Develop and market C cross compilers and other development tools for embedded systems based upon the 8051, 68000, CPU32, ColdFire and other chip families. Host environments include Windows NT, Windows 95 and DOS.
- http://www.crossware.com/

C Cross-Compilers
- For the Motorola 68HC11, Microchip PIC, 8051 microcontroller families. Includes both free and commercial products.
- http://ee.cleversoul.com/compilers.html