Author: Gerd Isenberg
Date: 16:07:51 12/23/02
Go up one level in this thread
On December 23, 2002 at 16:13:21, Bas Hamstra wrote:
>Gerd,
>
>Those fill routines are really neat. I have a few tiny enhancements and am
>working on more. How about this:
>
>// determine where white pawns can go safely, with a floodfill up:
>WSafePath = FFillUp(WPawns, ~(AllPawns|BDominated) );
>
>// now we can calc "pawn-defendable" more accurately:
>WDefendable = ((WPawnAttacksRight >> 16) & WSafePath) << 7 |
> ((WPawnAttacksLeft >> 16) & WSafePath) << 9 ;
>
>// to be used in backward pawns:
>WBackWard = ((~AllPawns & BDominated) >> 8) & WPawns & ~WDefendable;
>
>Best regards,
>Bas.
Hi Bas,
Wow, absolutely great!!!
Pawn-defendable is really more accurate.
I guess FFillUp(g, p) is Steffan's FillUpOccluded and WPawns are therefore
member of WSafePath.
BitBoard FFillUp(BitBoard g, BitBoard p)
{
g |= p & (g << 8);
p &= (p << 8);
g |= p & (g << 16);
p &= (p << 16);
return g | (p & (g << 32));
}
What do you think about (2.rank) pawns thay may push safely one step foreward,
but became backward afterwards?
Regards,
Gerd
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