I once did the reverse karnaugh mapping on a set of expressions to minimize their complexity; the input set was 7 bits. Specifically, I created an instruction

I once did the reverse karnaugh mapping on a set of expressions to minimize their complexity; the input set was 7 bits. Specifically, I created an instruction mapping on a 7b opcode space such that the decode logic for the critical paths was short (eg, branch decode). It took multiple sheets of paper, a few tries, and a couple of days, but it wasn't too bad.