Show HN: Decomp Academy – Learn to decompile GameCube games into matching C (decomp-academy.dev)

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

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

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.

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This is cool as hell.

On the first lesson, it tells me there's a target on "the right". There isn't anything to the right, I've in clue where to look.

Dumb question about reverse engineering binaries: is there a way to only do it piecemeal? I'm eventually waiting for LLMs and harnesses to get good enough to reverse engineer BFME (old Lord of the Rings game that still has an active modding community), but it's a multi GB sized game that would have to be done in bite-sized pieces.

Basically; can you reverse engineer in bite sized pieces, and recompile/customize their behavior, without needing to do it all at once?

I recently heard that Super Mario 64 (N64) modding community reverse engineered the game enough to recreate more-or-less accurate C code that can be compiled in binaries to execute on many popular target architectures. Have you managed to get beloved games into modifiable C code? Or is it more common to invest a lot of work to document assembly language functions? I know some old assembly but no idea what is involved at a high level. Maybe you explain in your lessons?

Also, how to folks obtain binaries? Presumably unless there is a source code breach or vulnerability, source never gets exposed, is thst correct?

Seems like a cool idea, but I can't even complete the first task. The compiler service seems to be broken, since in both lessons and the playground I just get "Could not write source: No space left on device (os error 28)".

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Dumb question — can LLM be used to reverse-engineer firmware blobs or binary only drivers for Linux, to create open-source drivers, for example, for unsupported smartphones?

Is there something similar to learn ARM decompiling?

> If even 1 instruction or bit is off, that's a fail.

Does this assume having access to the exact version of the compiler use, or can it be done with a different compiler in practice?

And do you care about things like binary layout, or just instruction match? (Does that ever matter in practice?)

Love the idea! Assembly has been on my forever-list to eventually learn. I have worked through the warmup exercises, but I doubt I'll have the time to continue much past that. A few points of note:

- Not a fan of the purple theme, it screams "AI-generated". It's not a deal breaker, you can keep it if you have more important concerns, but just something to point out

- It would be nice to have a "Chapter 0" for a primer on assembly syntax. Does not have to be interactive, a few toy examples I can work out on paper would be good enough

- Maybe I just haven't seen it, but it would be nice to have a reference of all the various instructions. Your lessens explain them well enough, but I would like to have a list of all of them at a glance so I can look up instructions from earlier chapters later.

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Feasible to have light theme?

This was interesting, but actually trying to contribute to decomp.me was still really hard! I found a lot of code that seemed perfect except for instructions slightly out of order, or dead pop statements after the logical end of the function. I wasn't able to actually fix anything :(

Also, I wish there were a guide about how to start from nothing on a new GC game. That's more interesting to me than putting the finishing polish on a decomp project that already "works" functionally.

I'd enjoy having something like this but for x86/64 :)

Hi OP, I would be careful if you profit from this project in anyway. Nintendo is not a company that takes reverse engineering of their hardware or games lightly. You will probably hear from their lawyers next week :(

That's awesome! I have been playing with the idea of doing a Tales of Symphonia decomp. More than 10 years ago I started the high-res texture pack, which the community has now carried further than I ever did. But it would be totally awesome to be able to mod the game further and run it on other consoles without the godawful framerate downgrade.

Interesting exercise. Why does 1/1 matching to original asm matter, though? Maintaining same timing as original game?

The browser-first approach is a bigger deal than it sounds. Every time I've looked at reverse engineering, I got stuck somewhere between "install this ancient compiler" and "patch this SDK". Being able to just open a tab and start experimenting removes a huge amount of friction.