Yes, they did a really good job. It handles the logic, but keep in mind the ROM itself is going to have operations that talk to the hardware that does things that just don’t exist in the code. The function will actually be in the hardware. Those pieces still have to be supplied of course.
They probably mean the Super Mario 64 Decompilation Project.
The goal was to turn the finished ROM back into unable code, that would do 1:1 the same thing. They finished a couple of years back.
https://github.com/n64decomp/sm64
Yes, they did a really good job. It handles the logic, but keep in mind the ROM itself is going to have operations that talk to the hardware that does things that just don’t exist in the code. The function will actually be in the hardware. Those pieces still have to be supplied of course.