On 6/17/07, Ron Johnson <ron.l.johnson@xxxxxxx> wrote:
On 06/16/07 17:05, Alexander Staubo wrote: > On 6/16/07, Ron Johnson <ron.l.johnson@xxxxxxx> wrote: >> > Hardware acceleration for quickly counting the number of >> > set/unset/matching bits? >> >> x86 doesn't already do that? > > I don't think so. The fastest way, I believe, is to use precomputed > lookup tables. Same for finding the least/most significant set/unset > bit, and other operations useful for dealing with bit vectors. A couple of new AMD Barcelona opcodes might help do that: http://www.anandtech.com/showdoc.aspx?i=2939&p=6
Very cool. Thanks for the pointer. Alexander.
