Re: Trapdoors

...

Interestingly enough, there seems to be no such instruction in the VAX ...

but i believe the vax has ffs (find first set) instruction, which seems to have similar uses (whatever they may be).

peter

But that's not a population count (all bits set count) instruction. In the Motorola 68020/30/40, there's BFFFO, for Bit Field Find First One, if anyone was curious about 'find first set' instructions. Might as well mention that the 386/486 have BSF and BSR, Bit Scan Forward and Reverse, but now we're just getting into run-of-the-mill bit manipulation.