> I would be interested in looking at the data sheet for this chip. I > didn't see which chip it was. The thing that has me curious is the > negative shift counts. Can a right shift of a negative count (of > some type (rotate?)) substitute for a left shift when the shift is > greater than 16?
This chip (m16c/m32c) does not have separate left/right shift opcodes. All shifts take signed counts; positive shifts one way, negative shifts the other way. Shifts are defined for counts in the range -16..16. Outside that range, they're undefined. Experimentation has shown that above that, counts wrap (i.e. counts are 0, 1, ..., 15, 16, 1, 2, ...).
