Author: Robert Hyatt
Date: 08:13:27 09/27/01
Go up one level in this thread
On September 27, 2001 at 09:55:56, Tony Werten wrote: >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 yes. I only need "all pieces" rotated. I need those to let me look up sliding piece moves rather than having to iterate down ranks/files/diagonals. Sliding pieces are the _only_ place where I need them. > >>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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