Package atasm

6502 cross-assembler

http://atari.miribilist.com/atasm/

ATasm is a 6502 command-line cross-assembler that is compatible with the
original Mac/65 macroassembler released by OSS software. Code
development can now be performed using "modern" editors and compiles
with lightning speed.

General Commands
Command Description
atasm assembler targeted for the 6502 CPU with Atari-specific features