CC65 is a C cross-compiler for 6502 and 65C02 systems.  CC65 includes
a powerful macro assembler, a debugger, an archiver, and a highly
configurable linker.  The linker supports overlays, ROMable code, and
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.  A 6502 simulator is available in the distribution
but is not currently installed by the FreeBSD port/package.

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
        - Commodore VIC20
        - CBM 600/700 family (programs run in bank 1)
        - Newer PET machines (not 2001)
        - The Apple ][
        - Atari 8bit machines
        - The Oric Atmos (beta)

The assembler and linker also support 65816 as a target.

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