Atom

Atom is a single-pass Z80 assembler written in Z80. It runs on CP/M 2.2 and as a desktop command through a Z80 emulator. Both use the same assembler core.

On the desktop, Node.js 20 or later is required:

npm install --global atom-z80
atom main.asm

This writes build/main.bin. Other output formats include Intel HEX, CP/M COM, listings and Debug80 D8 maps.

For CP/M, copy ATOM.COM to your disk and run ATOM HELLO to assemble HELLO.ASM. The download site also has a disk image that runs in Triptych.

Guides

• Using Atom: a first program, output files and CP/M usage
• The language: labels, expressions and directives
• The Node API: assembly from JavaScript

Building

From a source checkout:

npm install
npm run build
npm test

npm run verify:build rebuilds and compares the checked-in native images. npm pack creates an installable Node package.

The release scripts prepare the CP/M downloads, Triptych disk and Pages site. npm run release:check checks the build and tests before a version tag triggers the GitHub release workflow. npm publish runs the same checks before publishing the desktop package.

Atom's human-authored work is licensed under GPL-3.0-only. The authorship and LLM transparency policy describes tool use and the treatment of generated material.