5/1/2026 at 1:23:27 AM
First of all, super cool. I have a soft spot for SimTower as well. :)> I didn’t want to do a function-by-function port. First, APIs may be copyrightable - and copying a binary that closely might implicate copyright more than an approach closer to clean-room design. But it was clear that I needed some level of feedback from the ground-truth binary in order to provide a hill for the LLM to climb on the reimplementation.
Interesting, but isn't this what, say, the Ocarina of Time reverse engineer port does[1]? I imagine the fact that this hasn't been served a takedown notice from Nintendo is a proof that it's defensible? Or at least that there's precedent, ha.
Anyway, this is really cool. I genuinely think the only thing that's missing for me to waste an afternoon here is the sound effects!
by johnfn
5/1/2026 at 8:53:37 AM
It is not proof. It is a clear derived work infringing on the copyright of Nintendo.by charcircuit
5/1/2026 at 9:55:13 AM
Depends of the country, a lot of countries have exceptions for interoperability (at least the whole EU) and since these projects are mainly used to make ports to other systems, it may be covered.by realusername
5/1/2026 at 1:21:25 PM
This is an absolutely ridiculous interpretation. There is no interoperability here at all, you are literally just copying the work in question.It is like claiming that compiling Samba to run in $NEW_PLATFORM suddenly strips Samba of the GPLv3.
by AshamedCaptain
5/1/2026 at 2:09:24 PM
You absolutely aren't copying the work, recompilation projects are intensive work and a re-imagining of what the source code could look like. Compilation is still a one way process.And then for the legal part, that's why it's called an exception.
by realusername
5/1/2026 at 2:56:56 PM
There is little to no creative work whatsoever if you end up with exactly the same game; and often they end up with exactly the same binary as well. Source translations are derivative works almost by definition. It doesn't matter what magic you use to generate it.And again, where is the interoperability here? Interoperability exception would apply if there was whitebox cryptography, Nintendo logo-style things or anything else where the only method for the work to run would be to violate copyright of _exactly that_. Under no circumstances you can simply copy & distribute the entire work (or derivates) while claiming "interoperability exception!". It makes utterly no sense.
by AshamedCaptain
5/1/2026 at 3:00:37 PM
I disagree, the creative work is in figuring out what the game does, and the resulting recompilation is completely different from the original source code.And then for the interoperability, these decompilation projects are primarily made to target other systems, not the original platform. That's the textbook definition of interoperability.
Let's be real, N64 and the PS1/PS2 (where most of these projects are based) are crumbling old platforms at this point and these projects are sometimes the best way to run games when they exist.
by realusername
5/1/2026 at 3:07:18 PM
Decompilation produces a derivative work. This is not up for debate, or disagreement.The exception for interoperability only applies to _the minimum required_ for interoperability. You can use this exception to distribute e.g. game authorization code even if copyright would not allow you to do it.
You _cannot_ use this as an excuse to pirate the entire program, much less to create your own derivative work and distribute it!
This is just wishful thinking that comes up every so often in these threads (now it is the 5th time I see this parroted here). And then, when Nintendo inevitably shuts everything down, cue the crying. This ignorance is simply setting these projects for failure.
by AshamedCaptain
5/1/2026 at 3:28:49 PM
Your interpretation, I have mine. As far as I know, none of these recompilation projects ended up in any EU court yet so your interpretation is as valid as mine.And Nintendo can pound sand, sorry. The only realistic ways to play those aging games is on an emulator or recompilation projects nowadays.
Nintendo also didn't strike these projects, maybe they are afraid of making a precedent.
by realusername
5/1/2026 at 3:37:28 PM
So, wishful thinking it is.There is a bazillion of jurisprudence about decompilation in the EU . Just search for your favorite case. I'm based in the EU (France). But FYI, despite what you may think, in practice the US is more lax about this than the EU is.
In the EU, for example, decompilation even if you don't distribute may very well be illegal (because it would be an unauthorized temporary copy of the program); the US courts are way more lax when it comes to these temporary never-distributed copies (which are almost always fair use, a concept that doesn't exist per-se in the EU). This is a big problem in the EU for security research (which obviously does not fall into interoperability).
Emulation would be acceptable, which is yet another reason the interoperability clause does not apply (since you _already_ have a way to interoperate that doesn't require distributing copyrighted software, and the EU interoperability clause very explicitly says that then it does _not_ apply).
by AshamedCaptain
5/1/2026 at 6:16:45 PM
Derivative works aren't some unknowable arcane legal term. They're a pretty fundamental aspect of copyright law. The canonical examples of derivative works are things like adaptation of a book to a film, translation of a book, or a sequel.And given these examples, it's very clear that recompilation to play on modern hardware is quite similar in spirit to translating a book into a different language, which makes it a derivative work. The other alternative is that there is insufficient creativity in the recompilation effort to merit independent copyright at all, in which case it's just plain copying of the original work. In either case, it's infringement.
by jcranmer
5/1/2026 at 11:16:11 AM
> APIs may be copyrightableDidn't Google v. Oracle disprove this?
by MrDOS
5/1/2026 at 12:30:52 PM
Not quite. Google v Oracle ducked the question of API copyrightability (that was one of the main complaints of Thomas's dissent), instead saying that Google's use of the APIs were very definitely fair use in a sufficiently general manner that any clean room implementation of API for compatibility is very definitely fair use.by jcranmer