extern Bitboard AttackSpanMask[COLOR_NB][SQUARE_NB];
extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
+const Bitboard BlackSquares = 0xAA55AA55AA55AA55ULL;
/// Overloads of bitwise operators between a Bitboard and a Square for testing
/// whether a given bit is set in a bitboard, and for setting and clearing bits.
}
+/// shift_bb() moves bitboard one step along direction Delta. Mainly for pawns.
+
+template<Square Delta>
+inline Bitboard shift_bb(Bitboard b) {
+
+ return Delta == DELTA_N ? b << 8 : Delta == DELTA_S ? b >> 8
+ : Delta == DELTA_NE ? (b & ~FileHBB) << 9 : Delta == DELTA_SE ? (b & ~FileHBB) >> 7
+ : Delta == DELTA_NW ? (b & ~FileABB) << 7 : Delta == DELTA_SW ? (b & ~FileABB) >> 9
+ : 0;
+}
+
+
/// rank_bb() and file_bb() take a file or a square as input and return
/// a bitboard representing all squares on the given file or rank.
/// the same color of the given square.
inline Bitboard same_color_squares(Square s) {
- return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL
- : ~0xAA55AA55AA55AA55ULL;
+ return BlackSquares & s ? BlackSquares : ~BlackSquares;
}