Author: Russell Reagan
Date: 10:18:12 05/25/02
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On May 25, 2002 at 13:01:10, Gian-Carlo Pascutto wrote: >On May 25, 2002 at 12:58:58, Russell Reagan wrote: > >>I realize that you have to calculate the occupation of the rank/file/diagonal, >>but calculating the occupation of the rank/file/diagonal involves ray tracing > >No > >You can do this with some shifting/anding > >-- >GCP I suppose it depends on how much "some shifting/anding" is, because you can calculate attacks and mobility using "some adding/testing" (a.k.a ray tracing). It seems to me like doing a little shifting and anding isn't clearly superior to doing some adding and if testing. So, am I missing something? Perhaps it is a slight bit faster and the couple of cpu cycles you save will eventually add up, but even with 64-bit computing, this doesn't seem like it would give you this giant boost that people talk about. Especially on a 32-bit machine, that shifting and anding that you talk about is twice as expensive since it has to do it twice for each 32-bit segment. So while it sounds nice when you hear someone describe bitboards, is it really that much better? I still don't get it. Russell
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