It's an amazing piece of work: Those 617 lines are in its own C subset, so it can compile itself into a native code ELF version.

This evolved into bellard's "tcc" compiler, which is the fastest (compile-time wise) available on linux, the only one I'm aware of that can be used as a library to run code in memory (without having to generate an .so and load that). And it's output performance, while lacking compared to -O3 gcc or clang - is not too shabby!