Case study

Combat: an annotated Atari 2600 disassembly

A commented 6502 assembly listing reconstructs Combat, the Atari 2600 tank, biplane and jet game, aiming to explain every instruction, memory location and table. Assembled with DASM it yields an image that differs from the cartridge ROM only in the unwritten padding bytes before the startup vectors. The header maps all 27 game variations to their missile, maze and cloud options, and main-loop routines carry Atari's original names, taken from presentation notes.

Targets: Game
Category: Independent reconstruction cases
Relationship: Independent reconstruction project
Sources reviewed: 2026-11-09

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Requirements & limits

Prerequisites: DASM and the vcs.h header that the listing includes.
Testing evidence: The assembled image matches the cartridge ROM except for a few unwritten bytes before the startup vectors, which DASM sets to zero and the cartridge holds as $FF.
Scope: Some introductory VCS programming and historical comments were removed; the listing assumes basic familiarity with VCS programming.
License: No licence stated on the project page.

Cite

BibTeX

@misc{combat-atari-2600-disassembly-case,
  title = {{Combat: an annotated Atari 2600 disassembly}},
  howpublished = {\url{https://www.qotile.net/minidig/disassembly/dicombat.asm}},
  url = {https://www.qotile.net/minidig/disassembly/dicombat.asm},
  urldate = {2026-11-09},
  note = {Awesome REA entry: \url{https://awesomerea.org/resources/combat-atari-2600-disassembly-case/}}
}

Plain text

Combat: an annotated Atari 2600 disassembly. https://www.qotile.net/minidig/disassembly/dicombat.asm (accessed 2026-11-09). Awesome REA entry: https://awesomerea.org/resources/combat-atari-2600-disassembly-case/

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