CC65 is a C cross-compiler for 6502 systems.  CC65 includes a
powerful macro assembler, a debugger, an archiver, and a highly
configurable linker.  The linker supports overlays, ROMable code,
split output, among other features.  The compiler supports a large
subset of ISO C (as per the ISO 9899 specification) and can compile
the uIP TCP stack.

It is easy to write code for standalone 6502 boards (target none).  In
addition, particular support for the following targets is included:

        - C64 and C128
        - the GEOS operating system for the C64 and C128
        - Commodore C16, C116, Plus/4
        - CBM 600/700 family (programs run in bank 1)
        - Newer PET machines (not 2001)
        - The Apple ][
        - Atari 8bit machines

The assembler and linker also support 65816 as a target.

WWW: http://www.cc65.org/