SourceGen Disassembly Projects

This is a collection of 6502 software disassembly projects. The machine-language code and embedded graphics have been converted to readable form with 6502bench SourceGen, a disassembler for code written in 6502, 65C02, and 65816 assembly language. Unlike most disassemblers, it allows you to develop the disassembly interactively, in an assembler-neutral format, and can generate working assembler code for multiple cross-assemblers (currently 64tass, ACME, cc65, Merlin 32).

Most of the listings here are fully-commented disassemblies, not just code dumps. In a few cases, e.g. Applesoft and Super Mario Bros., the project was created by "porting" an existing widely-available listing, and additional commentary has not been introduced.

The best way to peruse the listings is in SourceGen, since that gives you access to cross-reference data for code and variables, quick navigation, and other handy features. Because not everyone has a Windows PC, I've used SourceGen's "export to HTML" feature to generate listings that can be viewed on any device. These use generic assembler directives and are not expected to assemble directly. See the notes for some additional commentary.

Graphical data is converted to GIF images for the HTML listings. Bitmap images are generated at original size, and scaled up by your web browser. Most browsers (e.g. Chrome and Safari) will do a nice pixel-art upscale, but some will do a "fuzzy" upscale that makes everything look blurry. Images tend to be tiny, so if you want to see them at a reasonable size (and can't view them inside SourceGen) it's probably best to download them and open them in an image viewer.

If you're contemplating disassembling something, I wrote down some general thoughts on the subject.

Apple II projects:

• System and peripheral card ROMs (1977+)
• GS/OS Components (1988-1993)
• SSI's RDOS (1986)

• ABM (1980)
• AppleVision (1977)
• Bill Budge's 3-D Graphics System and Game Tool (1980)
• Bomber (1978)
• Caverns of Freitag (1982)
• Deathmaze 5000 (1980)
• Elite (1984)
• Epoch (1981)
• Micro-Painter (1980)
• Phantoms Five (1980)
• Sabotage (1981)
• Scott Adams Adventures (1980)
• Space Eggs (1981)
• Starship Commander (1981)
• Stellar 7 (1983)

• Bonus: AppleWin debugger cheat sheet

Atari 2600 (VCS) projects:

• Adventure (1979)

Nintendo Entertainment System (NES) projects:

• Super Mario Bros. (1985)

Coin-op video arcade projects:

• Asteroids (1979)
• Battlezone (1980)
• Centipede (1981)
• Missile Command (1980)

• Bonus: Working with the MAME debugger

Other Disassemblies

Links to non-SourceGen disassemblies, as well as source code for classic titles published by the original authors.

• Apple II projects
• Video Arcade projects

There's a long list of BBC Micro game projects in this forum post, and this list has links to projects for games on a variety of platforms.

A nifty video about resolving a mystery in the C64 port of Silicon Warrior using Retro Debugger and SourceGen is here.

Some miscellaneous stuff is collected here.

Copyrights & Licensing

The legal status of the contents of this site is mixed. For all that follows please note that I Am Not A Lawyer.

• The original binaries are copyright by the original authors. Most of the software was written 30 or 40 years ago, but (depending on circumstances and where you live) copyright protection can last for much longer. All of the project pages and disassembly listings note the declared copyright holder.
• Visualizations generated from bitmap and wireframe data are likely covered by the original copyright.
• SourceGen project files do not contain any part of the source material, just labels, comments, visualization parameters, etc. These are copyright by the person who created the project.
• The HTML disassemblies contain both the original material and the labels, comments, etc. This means the material is copyright by both sets of authors.

Rules regarding abandonware and "fair use" doctrines may be relevant.

Unless otherwise noted, all SourceGen project files (.dis65, .sym65) hosted on this site are distributed under terms of the Creative Commons Attribution 4.0 license. This allows you to share and modify the projects, for any purpose, requiring only that you attribute the source. New source code, such as visualization generators and odd bits used to assist disassembly, use the same Apache 2.0 license that SourceGen does.

All visualizer output and screen shots are also distributed under terms of the Creative Commons Attribution 4.0 license, though as noted earlier the authors of the original work likely have a claim as well.

Finally: it is not my intent to deprive the original authors of any of their rights, or to profit from their work. This site is intended as a homage to the amazing things they built.