The cc65 is a cross-compiler package for old ( and new ) 6502 -based computer architectures. It includes a compiler for the C programming language, a macro assembler, linker, archiver and some other tools. The compiler package also allows for the development of programs for the C64, C128, Apple II and Atari home computers. Through a good program library it has performed with the cc65 very easy to develop programs for the graphical user interface GEOS ( C64/128 versions).

The compiler supports nearly all the C programming language. The most important missing piece of the language are floating-point numbers, so calculations are possible only with integers. The functions of the standard C library are supported, as far as they are useful to implement on the target systems.

Cross-system programming interfaces


  • Conio - Direct input and output via keyboard and screen
  • Dio - Direct disk access at block level


  • Em - Supports various kinds of memory extensions in a unified way
  • Joystick - a relative input device
  • Mouse - absolute input device
  • Serial - Supports input and output via RS -232 and similar interfaces.
  • Tgi - uniform interface for a variety of graphics modes

Examples of projects

  • Contiki ( Internet Program Suite)
  • Zoo Mania ( Game )
  • IP65 ( protocol stack )
  • Vm02 (Java VM)
  • Easy Flash ( Tool)