extern Bitboard RankBB[RANK_NB];
extern Bitboard AdjacentFilesBB[FILE_NB];
extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
-extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
extern Bitboard DistanceRingBB[SQUARE_NB][8];
extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB];
+
+
+/// Magic holds all magic bitboards relevant data for a single square
+struct Magic {
+ Bitboard mask;
+ Bitboard magic;
+ Bitboard* attacks;
+ unsigned shift;
+};
+
+extern Magic RookMagics[SQUARE_NB];
+extern Magic BishopMagics[SQUARE_NB];
/// Overloads of bitwise operators between a Bitboard and a Square for testing
/// attacks_bb() returns a bitboard representing all the squares attacked by a
/// piece of type Pt (bishop or rook) placed on 's'. The helper magic_index()
/// looks up the index using the 'magic bitboards' approach.
-template<PieceType Pt>
-inline unsigned magic_index(Square s, Bitboard occupied) {
-
- extern Bitboard RookMasks[SQUARE_NB];
- extern Bitboard RookMagics[SQUARE_NB];
- extern unsigned RookShifts[SQUARE_NB];
- extern Bitboard BishopMasks[SQUARE_NB];
- extern Bitboard BishopMagics[SQUARE_NB];
- extern unsigned BishopShifts[SQUARE_NB];
-
- Bitboard* const Masks = Pt == ROOK ? RookMasks : BishopMasks;
- Bitboard* const Magics = Pt == ROOK ? RookMagics : BishopMagics;
- unsigned* const Shifts = Pt == ROOK ? RookShifts : BishopShifts;
+inline unsigned magic_index(const Magic& m, Bitboard occupied) {
if (HasPext)
- return unsigned(pext(occupied, Masks[s]));
+ return unsigned(pext(occupied, m.mask));
if (Is64Bit)
- return unsigned(((occupied & Masks[s]) * Magics[s]) >> Shifts[s]);
+ return unsigned(((occupied & m.mask) * m.magic) >> m.shift);
- unsigned lo = unsigned(occupied) & unsigned(Masks[s]);
- unsigned hi = unsigned(occupied >> 32) & unsigned(Masks[s] >> 32);
- return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
+ unsigned lo = unsigned(occupied) & unsigned(m.mask);
+ unsigned hi = unsigned(occupied >> 32) & unsigned(m.mask >> 32);
+ return (lo * unsigned(m.magic) ^ hi * unsigned(m.magic >> 32)) >> m.shift;
}
template<PieceType Pt>
inline Bitboard attacks_bb(Square s, Bitboard occupied) {
- extern Bitboard* RookAttacks[SQUARE_NB];
- extern Bitboard* BishopAttacks[SQUARE_NB];
-
- return (Pt == ROOK ? RookAttacks : BishopAttacks)[s][magic_index<Pt>(s, occupied)];
+ const Magic& M = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
+ return M.attacks[magic_index(M, occupied)];
}
-inline Bitboard attacks_bb(Piece pc, Square s, Bitboard occupied) {
+inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
+
+ assert(pt != PAWN);
- switch (type_of(pc))
+ switch (pt)
{
case BISHOP: return attacks_bb<BISHOP>(s, occupied);
case ROOK : return attacks_bb<ROOK>(s, occupied);
case QUEEN : return attacks_bb<BISHOP>(s, occupied) | attacks_bb<ROOK>(s, occupied);
- default : return StepAttacksBB[pc][s];
+ default : return PseudoAttacks[pt][s];
}
}