Author: Gerd Isenberg
Date: 13:04:13 02/26/06
Go up one level in this thread
Applying the old trick - not using the outer squares of the masked occupied ray
- makes perfect 6-bit range hashing possible. Most often there are only 32
occupied states per ray - only if the source is an outer square, there are 64
states on a eight square ray:
BitBoard preCalulatedAttacks[64][4][64];
struct SMagicMask {
BitBoard mask;
BitBoard magic;
};
// sq ::= 0..63 square index of a sliding piece
// dir ::= 0..3 kind of ray (two diagonals, horicontal, vertical)
occIdx64 = (occupiedBB & mm[sq][dir].mask) * mm[sq][dir].magic) >> 58;
attacks = preCalulatedAttacks[sq][dir][occIdx64];
Generated mm-values below in a separate longer post...
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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