Bitboard InFrontBB[2][8];
Bitboard StepAttacksBB[16][64];
Bitboard BetweenBB[64][64];
+Bitboard DistanceRingsBB[64][8];
Bitboard ForwardBB[2][64];
Bitboard PassedPawnMask[2][64];
Bitboard AttackSpanMask[2][64];
for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
SquareDistance[s1][s2] = std::max(file_distance(s1, s2), rank_distance(s1, s2));
+ for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
+ for (int d = 1; d < 8; d++)
+ for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
+ if (SquareDistance[s1][s2] == d)
+ DistanceRingsBB[s1][d - 1] |= s2;
+
for (int i = 0; i < 64; i++)
if (!Is64Bit) // Matt Taylor's folding trick for 32 bit systems
{
extern Bitboard InFrontBB[2][8];
extern Bitboard StepAttacksBB[16][64];
extern Bitboard BetweenBB[64][64];
+extern Bitboard DistanceRingsBB[64][8];
extern Bitboard ForwardBB[2][64];
extern Bitboard PassedPawnMask[2][64];
extern Bitboard AttackSpanMask[2][64];
kingSquares[Us] = ksq;
castleRights[Us] = pos.can_castle(Us);
+ minKPdistance[Us] = 0;
+
+ Bitboard pawns = pos.pieces(Us, PAWN);
+ if (pawns)
+ while (!(DistanceRingsBB[ksq][minKPdistance[Us]++] & pawns)) {}
if (relative_rank(Us, ksq) > RANK_4)
return kingSafety[Us] = SCORE_ZERO;