I hope that the CC0 license doesn't make any problems. It might though since decompilation does not remove the copyright of Capcom. Maybe just hope that they just don't care anymore
I'm so emotionally torn about all the awesome decompilation work done.
Too bad all the cool decompilation is happening for games on early 3D centric consoles. I say this a Quake fanatic. Low res textures combined with that blurry bilinear style filtering is a look that's not easy to love. It's just a generational thing I guess.
I'm pretty curmudgeony on 3D games. The gamecube and friends were the 2nd generation of 3D first game systems and most games that sold well were not simply am existing genre game but with 3D objects that will poke your eyes out.
Doesn't mean I liked them, or that they wouldn't have been better as a 2D game. But IMHO the graphics stopped distracting from fun games... OTOH, I played plenty of games on the Atari 2600 were the player character wasn't much more than a chonky pixel :p
From a preservation perspective, this is one of the least useful decomps ever, given how committed Capcom is to making sure RE4 is ported absolutely everywhere (kidding!)
Made using the leaked debug build and its symbols, which shows how meaningful the work the game preservation community that acquires and distributes these things is.
OTOH this is pretty off-putting:
> Where the compiler needed a particular source shape to reproduce a register choice or a schedule and no natural spelling was found, the construct is marked with a // COMPILER-DIFF: comment (644 of them: dead tests, empty asm("") launders and anchors, register T x asm("rN") pins, padding statements).
To me the value of a decomp isn't reproducing the original bytes per se (we already have the original bytes after all) - it's about reconstructing the understanding of the original game as represented by human-readable source code; getting byte-for-byte is just an indication that you've gotten it right. Needing to add a bunch of slop to force the compiler to match the original output is actually just an indication that you've gotten it wrong - and it's a demonstration of the danger of Goodhart's law, especially as it applies to AI.
You might find it interesting that I am working on AI-driven decomp of a PS1 game not by matching bytes but by having agents produce C code and test code. Agents submit a C proposal to the harness, the harness compiles their C proposal for the original function, then the test suite provided by the implementer runs against the original machine code and the compiled C code version. The line and branch coverage of both must be 100% and given identical inputs and starting RAM, the function return value and RAM state and RAM/MMIO read write sequence must be identical. This is done with a small MIPS simulator which can run all the tests extremely fast.
The reason I’m finding this is much faster than a traditional decomp is that while it’d be nice for the bytes to match, finding the perfect blend of compiler version, compiler args, permitting variables etc to try and find the perfect register assignments, etc is all very time consuming. My ultimate goal is not a byte for byte match, that’s just one way to ensure correctness. I’ve found agents are much faster and effective at reading the original assembly and understanding what’s going on then writing semantically equivalent C.
That's a great approach, I think byte matching is just popular because it's extremely easy to test in the end: are the bytes the same? While your approach requires putting far more trust into the tests.
Correct, this is just hacks for stuff you didn't manage to match exactly. Either that or your build environment isn't the same. Sadly, there are things which aren't really possible to reproduce in a byte-identical manner, things like exact file layout or variable declaration order, compilation order and that kinda stuff. And they might cause small but equivalent changes like different inlining/optimisation decisions, so it's really tricky to get it byte-exact.
Certainly, it's better if you don't have these. But if I was working on something like this, I think you release when you have something that covers most of the territory, and then refine it over time.
Maybe someone else comes and helps out here and there.
Despite all "hate" against AI in the (retro)-gaming scene I'm genuinely excited to see these kind of projects (not sure if this one involved any kind of AI) and emulation.
From a technical perspective emulation is absolutely amazing, it requires deep technical knowledge, an excellent understanding of the source system and the optimisations are on another level.
I browsed through a few random files in that repo. There are high-quality code comments everywhere I looked. AI is the perfect tool to do this sort of thing. Can you imagine a human sitting down and documenting a million lines of someone else's decompiled code?
Boggles my mind that there is hate for AI in retro-gaming. It's all about making existing things work. If it works and plays well, who cares if Claude did it in an afternoon or some human who spent a year of his life. In fact, I'd rather have Claude do it. Humans will get bored, get involved in community drama, disappear, etc. Unfortunate for the humans who are seeing their life's contribution to the scene made obsolete by a few kilowatt-hours in a datacenter, but good for the rest of us.
I really think the hate is just masked jealousy, now project managers, tpms and line managers can submit rather substantial code. That wasn’t possible before and it took away some value from devs (I say this as a dev of more than 25 years). I watch PM fix issues now instead of waiting for a dev. I understand the anger but these tools are not going away
Too bad all the cool decompilation is happening for games on early 3D centric consoles. I say this a Quake fanatic. Low res textures combined with that blurry bilinear style filtering is a look that's not easy to love. It's just a generational thing I guess.
Doesn't mean I liked them, or that they wouldn't have been better as a 2D game. But IMHO the graphics stopped distracting from fun games... OTOH, I played plenty of games on the Atari 2600 were the player character wasn't much more than a chonky pixel :p
Made using the leaked debug build and its symbols, which shows how meaningful the work the game preservation community that acquires and distributes these things is.
OTOH this is pretty off-putting:
> Where the compiler needed a particular source shape to reproduce a register choice or a schedule and no natural spelling was found, the construct is marked with a // COMPILER-DIFF: comment (644 of them: dead tests, empty asm("") launders and anchors, register T x asm("rN") pins, padding statements).
To me the value of a decomp isn't reproducing the original bytes per se (we already have the original bytes after all) - it's about reconstructing the understanding of the original game as represented by human-readable source code; getting byte-for-byte is just an indication that you've gotten it right. Needing to add a bunch of slop to force the compiler to match the original output is actually just an indication that you've gotten it wrong - and it's a demonstration of the danger of Goodhart's law, especially as it applies to AI.
The reason I’m finding this is much faster than a traditional decomp is that while it’d be nice for the bytes to match, finding the perfect blend of compiler version, compiler args, permitting variables etc to try and find the perfect register assignments, etc is all very time consuming. My ultimate goal is not a byte for byte match, that’s just one way to ensure correctness. I’ve found agents are much faster and effective at reading the original assembly and understanding what’s going on then writing semantically equivalent C.
Maybe someone else comes and helps out here and there.
From a technical perspective emulation is absolutely amazing, it requires deep technical knowledge, an excellent understanding of the source system and the optimisations are on another level.
Boggles my mind that there is hate for AI in retro-gaming. It's all about making existing things work. If it works and plays well, who cares if Claude did it in an afternoon or some human who spent a year of his life. In fact, I'd rather have Claude do it. Humans will get bored, get involved in community drama, disappear, etc. Unfortunate for the humans who are seeing their life's contribution to the scene made obsolete by a few kilowatt-hours in a datacenter, but good for the rest of us.