Author: Tony Werten
Date: 06:55:56 09/27/01
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On September 27, 2001 at 09:44:05, Robert Hyatt wrote: >On September 27, 2001 at 01:01:40, Will Singleton wrote: > >>On September 26, 2001 at 22:28:06, Robert Hyatt wrote: >> >>>The critical question then is are you copying any large structs around? Are >>>you doing a make/unmake or a copy/make approach (copy/make drains the PC >>>memory bandwidth to zero). >> >>I do copy/make, but my struct isn't that large (a few words). Could you >>elaborate on the problem with copy/make? >> >>Will > >In a much earlier version of Crafty, I did copy/make also, the idea being that >there is then no unmake at all. Using bitboards, I have 12 for the different >pieces, plus three rotated, plus two (white/black occupied) plus one for Only 3 rotated ? What's in them, all pieces ? Tony >bishops/queens and one for rooks/queens. A total of 19 (at least). Times >8 bytes. The PC has almost _no_ memory bandwidth. It is somewhere around >100mbytes/second depending on your machine, maybe as much as 2x that. The >"copy" operation fries that bandwidth + cache badly. I became over 2x faster >by going to make/unmake...
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