# cc65/cc65

cc65 - a freeware C compiler for 6502 based systems

Repository: https://github.com/cc65/cc65
Canonical: https://ross.abutalabs.com/products/cc65
Homepage: https://cc65.github.io
Language: C
License: Zlib
License Family: permissive
Last push: 2026-08-20T15:54:30+00:00

## Health v2 (maintenance only)
Score: 67/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 98, release rhythm 8, longevity 100
- inputs: {"age_days": 4913, "days_push": 13, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2687, forks 505 (observed 2026-08-28T04:07:10.810134+00:00)

## What it is
cc65 is a complete cross-development suite for 65(C)02-based systems, including a C compiler, macro assembler, linker, archiver, and simulator. It provides C runtime library support for many classic 8-bit machines such as the Commodore 64, Apple II, Atari 8-bit computers, and the NES.

## Use cases
- compile C programs for the Commodore 64
- write NES games in C
- cross-compile for Apple II
- develop Atari 2600 homebrew software
- assemble 6502 assembly code
- build software for retro 8-bit computers
- target the Commander X16 with C

## When to choose
- you need a C compiler targeting 6502-based retro hardware
- you want a full toolchain (assembler, linker, archiver) for 8-bit development
- you need runtime library support for classic machines like C64, Apple II, or NES

## When to avoid
- you target modern CPUs like x86 or ARM
- you need a hosted compiler running on 6502 hardware itself
- you require modern C standards compliance beyond what a small 8-bit compiler offers

## Facets
- artifact type: cli-tool
- maturity: active
- function: compiler, interpreter, developer-tools
- domain: compilers, embedded-systems
- platform: windows, cli, cross-platform
- tags: 6502, c-compiler, cross-compiler, retrocomputing, assembler, linker, commodore, atari, nes, 8-bit, retro-computing, game-development, linux, macos

## Member repositories
- cc65/cc65 (main) score 67

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:10.810134+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:17:45.610356+00:00, confidence not recorded.
  - readme: https://github.com/cc65/cc65 (fetched 2026-08-28T04:07:10.810134+00:00, sha b9fea13cd80a)
  - homepage: https://cc65.github.io (fetched 2026-08-29T09:59:47.247696+00:00, sha c85b49461dbb)
- Data as of 2026-08-30T08:39:29.467469+00:00.