23 Sep
2022
23 Sep
'22
11:28 a.m.
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