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...)

I was thinking of something similar as well, perhaps a section of this site after you've completed the course where we show functions from popular decomp projects that aren't 100% matched, and you can match it. Doing so will magic up a PR or something.. It's a great idea!

As for cheating, the community calls this a fake match. I don't check that the code you submit conforms to what I expect, I only check if the assembly matches. You can do interesting things where you do a series of bit shifts and bit masks, and you can replicate an equality operator `a == b` or a low clamp `x < 0 ? 0 : x`. I'm not sure if I'll lock this down or not, for people who have accounts, I can see their submissions so I think I'll play it by ear and see what happens. If it looks like people are constantly fake matching, I can look at tweaking the lessons or locking it down more

The purple theme seems fine and appropriate to me, given the GameCube’s color scheme - and some of the site feels almost Slippi-esque so there’s a bit of that angle too.

Is "the layout scream AI generated" the new Bootstrap ? I.e what people use to quickly convey their ideas (bad or good)

Ironically, for myself at least, the least it looks AI, the more I've spent time prompting for it to not look AI.

Most decomp projects (that I know of) are Ship of Theseus style projects where the minimum unit is a function, give or take alignment requirements and quirks of the compiler. On the MIPS side, tools like Splat and SPIM can help identify function and even source file boundaries, generate inline ASM C files[0], and write linker scripts to build a matching binary. You can then go through and replace the ASM functions one at a time until you just have C left.

0 - for example: https://github.com/Xeeynamo/sotn-decomp/blob/master/src/boss...

Yes, quite easily. It requires some setup, but the basic idea is that you create a DLL and a simple loader program which injects it into your target process. You can then use a hooking library like MinHook to replace individual functions with your own implementations. If the target application is in C++, you can additionally do vtable hooking and replace functions even easier (though it will always be a combination of the two techniques).

Have you tried? I've haven't tried anything huge but I've had LLMs decompile SNES ROMs for me.

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!

Makes one wonder, why should anyone embark on learning this intricate and time-consuming art of reverse engineering when LLMs are on their way to automate it in seconds...

Mario 64 was byte for byte decompiled to C. It was helped by using the Debug symbols accidentally(?) compiled into the final version of the game.

Otherwise they reference rips of the original game.

Most games will have been written in a higher level language first (like C or C++) and then compiled into assembly. With matching decomp, we write C, compile it to assembly, and see how much it matches the retail assembly. Using this we can write C that we theorise is almost identical to how it would have been written originally. There are things lost during the compilation process (like comments, function names, etc) these we have to name manually and it's a long process to do! But yes, the goal is to have C at the end and once you have C you can recompile using a different compiler and target any architecture you like

Having a baseline "this builds XYZ exactly as it shipped" is just the strongest possible guarantee that it's a fully accurate decomp with no surprises or bugs. Obviously you can have an interesting, useful decomp that works either way but it's much harder to prove that it's perfectly faithful.

Being absolutely sure that your code behaves the same as the original game, so that you have a strong baseline to go from.

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.

I'm not aware of anything that's similar to this for ARM.. but in the future there is certainly room to add this. For now I'm focusing on getting the current set of lessons up to scratch as a lot of them need improvement. Then I think I want to add C++ as a language and allow you to change which version of MWCC you can run

Yes, exact version of the original compiler is required.

Generally bit-for-bit equivalence to the original executable is expected. However I think for some cases where the original executable included debug info (eg. PS2 ELFs) then the unused-at-runtime sections need not match.

That is already happening for old games, and while they usually run on simpler CPUs than modern ones, I don't see why this couldn't be possible for binary Linux drivers.

The toolchain would also be easier to match, unless they were using some proprietary compiler you can't get your hands on.

Just lookup how they match the toolchain, and find an agent harness to do decompilation.

I wonder if doing this kind of stuff with more recent software will cause more legal problems though. I am not really sure of the legal status of the resulting code.

Most likely, this (reverse engineering) is one of the numerous things these LLM companies target. You can also assume all of the internet has been slurped up in to any frontier model. That doesn't mean what you want will be a one shot prompt though...

As I'm working in this area, I can say that the biggest problem isn't binary only drivers but spotty mainline support of core features (provided that we're talking about Android phones, not iPhones or old Windows mobile stuff)

Are you on mobile? You'll need to switch to the code/review tab to see. I think mobile support is a bit funky, I'll look at fixing that as soon as I can!

Just deploying a fix for this right now! Didn't expect this to be so popular haha

Quite safe in practice, even Nintendo games have had no issues. GTA 3 / Vice City decompilers did get sued though, but IIRC mainly because they did not comply with DMCA requests at all.

The risk is low assuming you respect a potential take down notice that comes in.