Author: Ralf Elvsén
Date: 14:24:16 01/29/02
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On January 29, 2002 at 07:03:24, Sune Fischer wrote: >On January 29, 2002 at 06:10:53, Ralf Elvsén wrote: > >> >>Yes, that was what I was trying to do. If (in this case) h1 is set you >>don't have to mask after the occ^(occ-2) -thing. I think the easiest way >>maybe is. >> >>x = (occ | 0x8080808080808080) >> square >>a = (x^(x-2)) >> square > I. My endless stream of errors continue: the last line should read a = (x^(x-2)) << square >Could be, hopefully there were a few redundant operations;) > >but 0x8080808080808080 is FILE8: >-------x >-------x >-------x >-------x >-------x >-------x >-------x >-------x > >how do you know what to mask with, a small table would be needed right? II. I have a suspicion there is something I am missing. Work it out and report back here please :) Ralf > >>>Anyway, it is easier to test and debug than rotated and it may even be faster >on some machines where memory bandwith is a huge bottleneck. >> >>Yes, I think it can be just fine for move generation. But I'm not so >>sure how it fits in regarding the other things now handled by e.g. >>rotated bitboards. > >We end up with two attack boards instead of one, so to check if a square is >attacked we need to check both boards, in principle. >If the attack boards are used frequently for other things than move generation, >then at some point it will be worth reversing the reversed board to get only one >attack board. > > >>Ralf >> >>> >>>>>Ralf
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