[silentbicycle]

There's a de-facto standard bytecode and virtual machine design for byte-compiled Prolog, known as the Warren Abstract Machine. There are links concerning it and derived designs here: http://news.ycombinator.com/item?id=1649138

Also, wamcc (http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.45.1...) compiles Prolog to C.