This report documents the implementation of a high performance Prolog system achieved by remicroprogramming a host general purpose computer. New microcode was added to a VAX 8600 computer to implement the Berkeley Programmed Logic Machine (PLM), a Prolog-specific architecture closely related to the Warren Abstract Machine. The mapping of the abstract resources of the PLM to the 8600 is described. Performance comparisons between this system and three other Prolog implementations are included. On average, this system performs three times better than compiled and twenty times better than interpreted systems available on the same hardware. In addition, this execution model provides 75% of the performance of the special purpose PLM coprocessor, after results are normalized to the cycle time of each machine.