A 6502 assembler written in Javascript

NOTE: This is still in pre-alpha stage. That means unstable, slow and ugly code lies ahead.

You're welcome to submit patches or features!

let Assembler = require('6502asm').Assembler;
let asm = new Assembler();

asm.assemble(`
  lda #$01
  cmp #$02
  bne notequal
  sta $22
notequal:
  jmp *
`)

// > { objectCode: [ 169, 1, 201, 2, 208, 2, 133, 34, 76, 8, 0 ],
//     symbolTable: { notequal: 8 } }

Uses Ecmascript 6 extensively so you need either Node 6+, or Babel to transpile to ES5 (especially if you need to run it on browsers).

You can install with npm:

npm install munshkr/6502asm.js

If you clone the repo, install all dependency packages with npm install.

Then execute npm test to run unit tests and verify everything works.

To use it as a library, use Assembler class, as shown in the example above.

There is also a command line program:

  Usage: 6502asm [options] <file>

  Options:

    -h, --help            output usage information
    -o, --output [file]   output object file (default: ./a.out)
    -s, --symbols [file]  output symbols table (in JSON)
    -d, --debug           print debugging info

Bug reports and pull requests are welcome on GitHub at https://github.com/munshkr/6502asm.js

Source code is released under Apache 2 license.