# Cosmic Ark: a commented Atari 2600 disassembly with PAL conversion

> Cosmic Ark for the Atari 2600 (Imagic, 1982) is reconstructed as an analyzed, labeled and commented 6502 assembly listing with NTSC and PAL builds. The PAL conversion rescales nearly all game speeds through the game's fractional addition so both versions play at the same pace, and optional switches enable size optimizations. The notes point out the leftover code for a non-cooperative two-player mode and the game's heavy use of status flags.

- Type: Case study
- Targets: Game
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-09
- Added to the catalog: 2026-11-10
- Original resource: <https://www.qotile.net/minidig/disassembly/CosmicArk.asm>
- Primary source: <https://web.archive.org/web/20260221014224/https://www.qotile.net/minidig/disassembly/CosmicArk.asm>
- Catalog page: <https://awesomerea.org/resources/cosmic-ark-atari-2600-disassembly-case/>
- Record JSON: <https://awesomerea.org/resources/cosmic-ark-atari-2600-disassembly-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/cosmic-ark-atari-2600-disassembly-case/index.md)

## Requirements & limits

- **Prerequisites:** A 6502 assembler and the vcs.h header that the listing includes; the listing itself defines TIMINT = $285, which older versions of vcs.h lack.
- **Limits:** Version 0.9. The author states that PAL meteor speeds do not match NTSC exactly and that some status flags may be misidentified.
- **License:** No licence stated on the project page.

## Primary sources

1. <https://web.archive.org/web/20260221014224/https://www.qotile.net/minidig/disassembly/CosmicArk.asm>
2. <https://www.qotile.net/minidig/>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.