# River Raid: an annotated Atari VCS disassembly of river generation and the kernel

> Activision's 1982 Atari VCS game River Raid is disassembled into labeled and commented 6502 assembly (version 0.9). Notes explain how random river sections of 16 blocks ending in a bridge are generated, how one fuel tank, enemy or house is placed per block, how a two-line kernel repeated twelve times draws each 32-line block with hardware-only collision checks, and how the score lives directly in the display pointers; switches add screensaver code and a training mode.

- 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/RiverRaid.asm>
- Primary source: <https://web.archive.org/web/20260223204810/https://www.qotile.net/minidig/disassembly/RiverRaid.asm>
- Catalog page: <https://awesomerea.org/resources/river-raid-atari-vcs-disassembly-case/>
- Record JSON: <https://awesomerea.org/resources/river-raid-atari-vcs-disassembly-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/river-raid-atari-vcs-disassembly-case/index.md)

## Requirements & limits

- **Prerequisites:** Assembling needs a 6502 assembler and the vcs.h Atari VCS header that the listing includes.
- **Limits:** Version 0.9 of the analysis, last updated in August 2001.
- **License:** No licence stated on the project page.

## Primary sources

1. <https://web.archive.org/web/20260223204810/https://www.qotile.net/minidig/disassembly/RiverRaid.asm>

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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.