They are going through and mechanically translating functions 1:1 from the original binary, so there aren't exactly any concerns with "clean-room reverse engineering" here.

You can still achieve that without having access to the original source code, so the implementation would be considered clean from copyright claims as long as it doesn't contain any copyrighted assets (which are necessary to achieve a perfect clone), but those can be injected during compilation from the original ROM that the end-user must acquire themselves.

In which country is this interpretation of copyright law valid ?

Soon: Freedows 12. "Your Honor, I just looked at the compiled code, so it must be considered clean from copyright claims!".

Copyright laws mostly covers the assets (images, texts, etc) and the actual implementation. If you happen to make your own implementation that leads to the same output when compiled, that would be considered fair use in most situations. As long as you didn't copy from the original source code as long as you're not distributing the assets or the compiled version, the copyright holder can't stop you from distributing your own work.

ReactOS and Wine exists and are reimplementations of copyrighted code.

> If you happen to make your own implementation that leads to the same output when compiled, that would be considered fair use in most situations as long as you didn't copy from the original source code as long as you're not distributing the assets or the compiled version.

Good luck trying to prove to any judge in the world that you came up with an implementation that happens to be exactly the same as the original game code, down to the same checksum, by pure chance.

What is this, "the ChatGPT defense"? Do you really think that code has intrinsically less right to copyright than art, or what?

>ReactOS and Wine exists and are reimplementations of copyrighted code.

Clean room reimplementations that don't even dare to look at the copyrighted code.

Copyright, specifically code will only let you protect the IMPLEMENTATION, the code the copyright owner specifically made, not the IDEA of the code.

> Good luck trying to prove to any judge in the world that you came up with an implementation that happens to be exactly the same as the original game code, down to the same checksum, by pure chance.

Not impossible if you reverse engineer the software and look how the binary code is behaving, emulators does this all the time.

A reimplementation of code that leads to the same binary output isn't covered by the copyright, as long as you don't share copyrighted assets or the actual binaries. What people do with the alternative source code is their business, you can't hold responsible that person for others' action.

> Not impossible if you reverse engineer the software and look how the binary code is behaving, emulators does this all the time.

We are not talking about a program that "produces the same binary output" when executed. We are talking about a program that _is exactly the same_ as the original one, bit-by-bit.

It is ridiculously impossible to "independently" discover a program that is _exactly the same machine code_ as the original program by just looking at the inputs and outputs of the original program. (Barring trivial programs, of course.)

This is not reverse engineering. This is just dissasembling and decompiling.

But they're not distributing the compiled output, only their own implementation of the source code which leads to that. If they happen to make their own source code which leads to the same assembly opcodes in the compiler, is that really copyright infringement?

"But Your Honor, I'm not distributing copies of the copyrighted program, just another program which happens to generate the copyrighted program bit-by-bit! All my original creation, even though I was literally looking at the copyrighted program while developing it..."

Do you think that I can just gzip gplprogram.c and then redistribute gplprogram.c.gz under the "Do What The Fuck You Want To Public License"?

Technically you would be distributing your own implementation, not the original source code. Copyright does allow you to do that. They just applied the concept of reproducible build on top.

Allow me to introduce you to ReactOS.

https://reactos.org/

And Nintendo is well-known to be hyper litigious fucks that will try to destroy their fans in court, even when they are within the legal bounds of copyright.