How does it actually recompile, does it use an existing tool? I can’t imagine the agent combs through every routine and hand translates the assembly.

Yes, it uses two already existing tools for the heavy lifting. Remill lifts the x86 machine code to LLVM IR, and LLVM then compiles that IR to ARM64. And no, nobody translates the assembly by hand luckily, not me nor the agent. All of these 150k functions go through this automatic chain I explained before.

What I wrote with Claude is basically everything else: custom LLVM passes, a hand-written runtime that replaces the Windows calls, a Direct3D 11 to Metal layer and the shader translation! Plus fixing the crashes one by one by iterating and playing. All details are in the Pipeline section of the README if you're interested: https://github.com/adrbn/bo2-mac#pipeline

> Remill lifts each function to LLVM IR, a chain of our own passes rewrites that IR, and the result is linked with a Win32 runtime written by hand, whose Direct3D 11 is drawn by Metal. There is no Wine and no JIT: the game runs as native code, in one process. About 150,000 functions are translated across the three executables. Only the short sequences that the copy protection hides run in a small x86 interpreter, and so does any code the translation missed, so a hole is built to cost speed rather than crash the game.