/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#if !defined(BITBOARD_H_INCLUDED)
#define BITBOARD_H_INCLUDED
#include "types.h"
CACHE_LINE_ALIGNMENT
extern Bitboard RMasks[64];
extern Bitboard RMagics[64];
extern Bitboard* RAttacks[64];
extern unsigned RShifts[64];
extern Bitboard BMasks[64];
extern Bitboard BMagics[64];
extern Bitboard* BAttacks[64];
extern unsigned BShifts[64];
extern Bitboard SquareBB[64];
extern Bitboard FileBB[8];
extern Bitboard RankBB[8];
extern Bitboard AdjacentFilesBB[8];
extern Bitboard ThisAndAdjacentFilesBB[8];
extern Bitboard InFrontBB[2][8];
extern Bitboard StepAttacksBB[16][64];
extern Bitboard BetweenBB[64][64];
extern Bitboard SquaresInFrontMask[2][64];
extern Bitboard PassedPawnMask[2][64];
extern Bitboard AttackSpanMask[2][64];
extern Bitboard PseudoAttacks[6][64];
/// 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.
inline Bitboard operator&(Bitboard b, Square s) {
return b & SquareBB[s];
}
inline Bitboard& operator|=(Bitboard& b, Square s) {
return b |= SquareBB[s];
}
inline Bitboard& operator^=(Bitboard& b, Square s) {
return b ^= SquareBB[s];
}
inline Bitboard operator|(Bitboard b, Square s) {
return b | SquareBB[s];
}
inline Bitboard operator^(Bitboard b, Square s) {
return b ^ SquareBB[s];
}
/// 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.
inline Bitboard rank_bb(Rank r) {
return RankBB[r];
}
inline Bitboard rank_bb(Square s) {
return RankBB[rank_of(s)];
}
inline Bitboard file_bb(File f) {
return FileBB[f];
}
inline Bitboard file_bb(Square s) {
return FileBB[file_of(s)];
}
/// adjacent_files_bb takes a file as input and returns a bitboard representing
/// all squares on the adjacent files.
inline Bitboard adjacent_files_bb(File f) {
return AdjacentFilesBB[f];
}
/// this_and_adjacent_files_bb takes a file as input and returns a bitboard
/// representing all squares on the given and adjacent files.
inline Bitboard this_and_adjacent_files_bb(File f) {
return ThisAndAdjacentFilesBB[f];
}
/// in_front_bb() takes a color and a rank or square as input, and returns a
/// bitboard representing all the squares on all ranks in front of the rank
/// (or square), from the given color's point of view. For instance,
/// in_front_bb(WHITE, RANK_5) will give all squares on ranks 6, 7 and 8, while
/// in_front_bb(BLACK, SQ_D3) will give all squares on ranks 1 and 2.
inline Bitboard in_front_bb(Color c, Rank r) {
return InFrontBB[c][r];
}
inline Bitboard in_front_bb(Color c, Square s) {
return InFrontBB[c][rank_of(s)];
}
/// Functions for computing sliding attack bitboards. Function attacks_bb() takes
/// a square and a bitboard of occupied squares as input, and returns a bitboard
/// representing all squares attacked by Pt (bishop or rook) on the given square.
template
FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
Bitboard* const Masks = Pt == ROOK ? RMasks : BMasks;
Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
if (Is64Bit)
return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);
unsigned lo = unsigned(occ) & unsigned(Masks[s]);
unsigned hi = unsigned(occ >> 32) & unsigned(Masks[s] >> 32);
return (lo * unsigned(Magics[s]) ^ hi * unsigned(Magics[s] >> 32)) >> Shifts[s];
}
template
inline Bitboard attacks_bb(Square s, Bitboard occ) {
Bitboard** const Attacks = Pt == ROOK ? RAttacks : BAttacks;
return Attacks[s][magic_index(s, occ)];
}
/// squares_between returns a bitboard representing all squares between
/// two squares. For instance, squares_between(SQ_C4, SQ_F7) returns a
/// bitboard with the bits for square d5 and e6 set. If s1 and s2 are not
/// on the same line, file or diagonal, EmptyBoardBB is returned.
inline Bitboard squares_between(Square s1, Square s2) {
return BetweenBB[s1][s2];
}
/// squares_in_front_of takes a color and a square as input, and returns a
/// bitboard representing all squares along the line in front of the square,
/// from the point of view of the given color. Definition of the table is:
/// SquaresInFrontOf[c][s] = in_front_bb(c, s) & file_bb(s)
inline Bitboard squares_in_front_of(Color c, Square s) {
return SquaresInFrontMask[c][s];
}
/// passed_pawn_mask takes a color and a square as input, and returns a
/// bitboard mask which can be used to test if a pawn of the given color on
/// the given square is a passed pawn. Definition of the table is:
/// PassedPawnMask[c][s] = in_front_bb(c, s) & this_and_adjacent_files_bb(s)
inline Bitboard passed_pawn_mask(Color c, Square s) {
return PassedPawnMask[c][s];
}
/// attack_span_mask takes a color and a square as input, and returns a bitboard
/// representing all squares that can be attacked by a pawn of the given color
/// when it moves along its file starting from the given square. Definition is:
/// AttackSpanMask[c][s] = in_front_bb(c, s) & adjacent_files_bb(s);
inline Bitboard attack_span_mask(Color c, Square s) {
return AttackSpanMask[c][s];
}
/// squares_aligned returns true if the squares s1, s2 and s3 are aligned
/// either on a straight or on a diagonal line.
inline bool squares_aligned(Square s1, Square s2, Square s3) {
return (BetweenBB[s1][s2] | BetweenBB[s1][s3] | BetweenBB[s2][s3])
& ( SquareBB[s1] | SquareBB[s2] | SquareBB[s3]);
}
/// same_color_squares() returns a bitboard representing all squares with
/// the same color of the given square.
inline Bitboard same_color_squares(Square s) {
return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL
: ~0xAA55AA55AA55AA55ULL;
}
/// first_1() finds the least significant nonzero bit in a nonzero bitboard.
/// pop_1st_bit() finds and clears the least significant nonzero bit in a
/// nonzero bitboard.
#if defined(USE_BSFQ)
#if defined(_MSC_VER) && !defined(__INTEL_COMPILER)
FORCE_INLINE Square first_1(Bitboard b) {
unsigned long index;
_BitScanForward64(&index, b);
return (Square) index;
}
#else
FORCE_INLINE Square first_1(Bitboard b) { // Assembly code by Heinz van Saanen
Bitboard dummy;
__asm__("bsfq %1, %0": "=r"(dummy): "rm"(b) );
return (Square) dummy;
}
#endif
FORCE_INLINE Square pop_1st_bit(Bitboard* b) {
const Square s = first_1(*b);
*b &= ~(1ULL<