Author: Robert Hyatt
Date: 08:15:17 11/20/02
Go up one level in this thread
On November 20, 2002 at 11:07:32, Sune Fischer wrote: >On November 20, 2002 at 10:57:01, Robert Hyatt wrote: > >>On November 20, 2002 at 05:44:10, Sune Fischer wrote: >> >>>On November 20, 2002 at 05:37:43, Steffan Westcott wrote: >>> >>>>On November 20, 2002 at 05:05:25, Sune Fischer wrote: >>>> >>>>> I believe that "move for move" 0x88 is faster because you don't have to do >>>>> that extra bit scan to get the square >>>> >>>>Which square are you referring to? Source square? Destination square? I may be >>>>able to help you... >>> >>>With bitboards (as I'm sure you know) you need a piece of assembler using bsf, >>>then you need to clear the bit afterwards. This is not needed with 0x88. >>> >>>ie: >>> while (padvances2) { >>> to=FirstOne(padvances2); >>> *move++=(to+16)|(to<<6)|(pawn<<12); >>> Clear(to,padvances2); >>> } >>> >> >> >> >>Wrong idea however. Most of the move generations done are for captures. 0x88 >>can't keep up with bitmaps there, because bitmaps generate _only_ capture moves, >>while 0x88 walks down each rank/file/diagonal skipping empty squares. > >Yep, wasn't that what I said?? Sorry. I didn't address that to the "right person"... :) an errant "back" and I was posting at the wrong place. Yes, I believe you did say that... I was trying to respond to the same thing you were responding too, but didn't quite make it. :) > >>that is one of the strengths of bitmaps. finding a bit is quick. Clearing it >>takes one >>cycle. not very expensive. > >I think that was my point exactly. > >-S.
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