What this is ​

xenolith is a static recompiler for Xbox 360 executables. It reads a XEX container, decodes the 64-bit PowerPC inside it, works out where the functions are, and writes C.

It is Linux only, and deliberately so. There is no Windows support and none planned.

Static, not emulated ​

An emulator decodes an instruction every time it runs one. A static recompiler decodes each instruction once, ahead of time, and writes out code that does the same thing. The result is a program rather than an interpreter, so the cost of decoding is paid at build time and never again.

The price is that everything has to be worked out without running anything. An emulator always knows where it is; a recompiler has to find every function, every basic block, and every branch target by reading the bytes. Where a branch goes through a register, it has to reconstruct the table the program would have read.

That is most of what this project is.

No per title configuration ​

The comparable tool for this job requires a hand written file per game. That file names every function boundary the tool could not find, the addresses of the eight register save and restore helpers, the addresses of setjmp and longjmp, and byte patterns to skip. A companion tool produces a second file listing every jump table, which for one title runs to 852 entries across 30,250 lines.

xenolith accepts none of that. There is no configuration file, no title database, and no place to write an address by hand. Everything is recovered from the image, or reported as unrecovered.

This is a constraint rather than a convenience. A tool that can be told the answer will be told the answer, and then nobody finds out that it could not work it out. Removing the option is what makes the coverage figure mean something.

What it will not do ​

• It will not run your game. The runtime interface is a declaration. Nothing maps guest memory, services an import, or creates a thread.
• It will not guess. An instruction the decoder does not recognize is reported as unknown. A function holding an instruction the semantic model cannot express is not emitted at all, because code that is right except in one place compiles and runs and is wrong, and nothing downstream can tell.
• It will not decrypt a title for you. No key material ships with it. See Key material.

The shape of the pipeline ​

Four crates, each usable on its own:

The xenolith binary exposes them as four subcommands. Each stage is checked against something produced independently before the next one is built on it, which is the subject of How it is checked.