Note that you just need to write an LLVM backend for this, not a full fledged Rust compiler. LLVM IR is somewhere between C and assembly so it should be about a

Note that you just need to write an LLVM backend for this, not a full fledged Rust compiler. LLVM IR is somewhere between C and assembly so it should be about as hard as writing a C compiler. Rust works fine without an OS. Some of the nice-to-have-stuff (inline assembly) aren't stable yet (I have been meaning to push for this with an rfc), but they'll get there.