Atari Assembler Editor

Atari Assembler Editor (sometimes written as Atari Assembler/Editor) is a ROM cartridge-based development system released by Atari, Inc. in 1981. It is used to edit, assemble, and debug 6502 programs for Atari 8-bit computers without the need for additional tools. It was programmed by Kathleen O'Brien of Shepardson Microsystems, the company which wrote Atari BASIC, and Assembler Editor shares many design concepts with that language implementation.

Assembly times are slow, making the cartridge challenging to use for larger programs. In the manual, Atari recommended the Assembler Editor as a tool for writing subroutines to speed up Atari BASIC,^[1] which would be much smaller than full applications. The Atari Macro Assembler was offered as an alternative with better performance and more features, such as macros, but it is disk-based, copy-protected, and does not include an editor or debugger. Despite the suggestion, commercial software was written using the Assembler Editor, such as the games Eastern Front (1941),^[2] Caverns of Mars,^[3] Galahad and the Holy Grail,^[4] and Kid Grid.^[5]

The source code to the original Assembler Editor was licensed to Optimized Systems Software who shipped EASMD based on it.