I'm experimenting with a P-code compiler to Z80 for CP/M for the past week. I've only implemented 35 instructions out of +/- 150. It compiles a Pascal program approximating Pi (spigot algorithm of Rabinovitz and Wagon) running at the same speed as the same program compiled with Turbo Pascal 3. 60s for 100 digits. With Euclidian division routines (16/16 and 16/8).

When I replace those routines by a naïve division routine by successive substractions it computes Pi in 50s for 100 digits ! The quotient never exceeding 18 must be the explanation of this 20% boost.