On 9/23/22 11:14, Randy Dawson via cctalk wrote: > On the top secret number cruching.... > > The Cray had an instruction called 'population count' > > asked for by the NSA. > > The number of bits on in a word, not sure what this was used for.
The CDC 6600 had a dedicated functional unit for this instruction. Wasted a lot of time trying to think up practical uses for it--totting up disk block allocation bitmaps was perhaps the most useful. --Chuck
