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Over the past few months I've been heavily involved in the decompilation community. I've been hands-on decompiling a beloved game from my childhood (Star Fox Adventures). I started this journey with zero prior decomp experience—and to make things worse I had never really touched C nor assembly either.

Learning how to decompile was challenging. It's difficult to find any good learning resources for it and any open-source projects for this are inactive and/or contain little actual learning material.

So I put together Decomp Academy! Decomp Academy is an interactive way to learn how to decompile PowerPC assembly back into C. The site runs a live Metrowerks CodeWarrior GC/2.0 compiler, converts your C into assembly, and then checks how close your assembly matches the target. If even 1 instruction or bit is off, that's a fail. This is the gold standard for video game decompilation and this is much stricter than a normal decompile.

As of writing there are 250+ lessons on the site and the lessons start at the very basics so anyone with a little programming experience should be able to jump straight in, even if you're not a C expert. Some lessons also have real functions taken from live open source decomp projects (Star Fox Adventures, Mario Party 4, Pikmin, Metroid Prime). The idea being you learn everything you need to know to be able to jump in and contribute to a real decompilation project when done.

The site is completely free, open source and you have access to all lessons without having to sign up. All lessons are stored in markdown in the repo (src/curriculum), it's trivial to add or modify lessons. The site is very new and the lessons are rapidly changing every day with a whole C++ section on the way. The site has already been well received by the decomp community and I'm happy to share it with HN. I'm very keen on others to contribute to this project and I hope this becomes the best resource on the internet for learning the art of decompilation. Please let me know what you think!

Source: https://github.com/JackPriceBurns/decomp-academy-fe

Comments

jackpriceburns•1h ago

The backend is closed source, but it runs all on AWS Lambda/DynamoDB/APIGateway and is written in Rust. Getting the compiler running in a Lambda was an adventure of it's own

rybosome•25m ago

I’d be interested in hearing more detail on that. I’m actually surprised you were able to get the compiler, I assumed it would be expensive and proprietary.

Retr0id•1h ago

I'd love it if there was some way to contribute to ongoing game decompilation projects, with a similarly streamlined web interface - it's something I'd be willing to dedicate some brain time to every so often, but setting up the toolchain etc. feels too much like work.

By the way, I was able to "cheat" on the second lesson with

    void identity(void) { return; }

I gave up at https://decomp-academy.dev/lesson/workflow-what-matching-mea... when I was presented with a wall of LLM-flavoured text

someone2639•1h ago

That's what decomp.me is for, when I'm stuck on a function in my own projects I usually set it up on there and link it in the codebase so anyone can pick it up. Sometimes I like to browse the front page and hope I know enough to silently match somebody else's function (usually stays as a hope though...)

jackpriceburns•1h ago

saturn8601•1h ago

Damn this is next level. Congratulations on your achievements!

When Fable was around I thought i'd test it by taking an old piece of Windows software from the late 90s/2000s(ModPlug Player) and seeing how well it could convert it to being a native Mac application.

I was blown away at how it got 85% of the way there in one prompt. Things such as writing a PE extractor, recovering the complete skin, menu tree, full accelerator table, all dialogs, and then it delved into the registry value names as well. Some more prompts got it to 99%(I was happy with that and stopped)

I then took an old 1999 DOS demoscene and yet again it did wonderful magic and got me a native mac build.

I dropped everything I was doing and just started going through all these old apps that I couldn't easily enjoy since im on a Mac. It got to the point where I was losing sleep over it(was just so excited).

The fun ended when I was stopped mid-project with the Fable ban. Opus just does not compare and essentially killed all the enthusiasm after the nth failure of it to complete the task.

It made me realize that among the efforts of the RE community, and the emerging capabilities of these frontier models, in the future we could have the possibility living in a renaissance of open computing if we want any software we see on the market to be forever remixed and tailored to our uses and completely open.

I don't know how the business and legal side will deal with this. There needs to be new frameworks and ways of thinking about this stuff.

I'm just happy that hopefully no code will ever be lost to the sands of time ever again.

jackpriceburns•57m ago

AI is being used in many retro game decomp projects!

One of the reasons I went down the path of learning decomp myself was because AI had hit a wall. Matching decomp is quite a bit harder than just normal decomp as even simple things like using an if/else instead of a terney actually change the assembly. AI did an amazing job of getting to 95% matches on nearly all functions, but once it got to that tail end, it started to struggle quite a lot and would often just claim "it's impossible". So that's when I pivoted and started learning actual decomp myself so that I could prompt AI better and finish off the star fox adventures decomp!