X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.h;h=b29f3e24fa1d5d29e230cde88c0105b0d8e6365f;hp=8d748eeed8615628ddd4b044df9c34aef4fcaeff;hb=0e89d6e7546d26a19a108d047b489d9ba6f7970c;hpb=cff9a8672c1da7d36bc54d168d10ea2b1ce5c728 diff --git a/src/bitboard.h b/src/bitboard.h index 8d748eee..b29f3e24 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -1,8 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file) Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -25,19 +23,21 @@ #include "types.h" +namespace Stockfish { + namespace Bitbases { void init(); bool probe(Square wksq, Square wpsq, Square bksq, Color us); -} +} // namespace Stockfish::Bitbases namespace Bitboards { void init(); -const std::string pretty(Bitboard b); +std::string pretty(Bitboard b); -} +} // namespace Stockfish::Bitboards constexpr Bitboard AllSquares = ~Bitboard(0); constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; @@ -75,6 +75,7 @@ extern uint8_t PopCnt16[1 << 16]; extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB]; extern Bitboard SquareBB[SQUARE_NB]; +extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB]; extern Bitboard LineBB[SQUARE_NB][SQUARE_NB]; extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB]; @@ -106,10 +107,11 @@ extern Magic RookMagics[SQUARE_NB]; extern Magic BishopMagics[SQUARE_NB]; inline Bitboard square_bb(Square s) { - assert(s >= SQ_A1 && s <= SQ_H8); + assert(is_ok(s)); return SquareBB[s]; } + /// 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. @@ -123,38 +125,39 @@ inline Bitboard operator&(Square s, Bitboard b) { return b & s; } inline Bitboard operator|(Square s, Bitboard b) { return b | s; } inline Bitboard operator^(Square s, Bitboard b) { return b ^ s; } -inline Bitboard operator|(Square s, Square s2) { return square_bb(s) | square_bb(s2); } +inline Bitboard operator|(Square s1, Square s2) { return square_bb(s1) | s2; } constexpr bool more_than_one(Bitboard b) { return b & (b - 1); } -inline bool opposite_colors(Square s1, Square s2) { - return bool(DarkSquares & s1) != bool(DarkSquares & s2); + +constexpr bool opposite_colors(Square s1, Square s2) { + return (s1 + rank_of(s1) + s2 + rank_of(s2)) & 1; } /// rank_bb() and file_bb() return a bitboard representing all the squares on /// the given file or rank. -inline Bitboard rank_bb(Rank r) { +constexpr Bitboard rank_bb(Rank r) { return Rank1BB << (8 * r); } -inline Bitboard rank_bb(Square s) { +constexpr Bitboard rank_bb(Square s) { return rank_bb(rank_of(s)); } -inline Bitboard file_bb(File f) { +constexpr Bitboard file_bb(File f) { return FileABB << f; } -inline Bitboard file_bb(Square s) { +constexpr Bitboard file_bb(Square s) { return file_bb(file_of(s)); } -/// shift() moves a bitboard one step along direction D +/// shift() moves a bitboard one or two steps as specified by the direction D template constexpr Bitboard shift(Bitboard b) { @@ -176,6 +179,12 @@ constexpr Bitboard pawn_attacks_bb(Bitboard b) { : shift(b) | shift(b); } +inline Bitboard pawn_attacks_bb(Color c, Square s) { + + assert(is_ok(s)); + return PawnAttacks[c][s]; +} + /// pawn_double_attacks_bb() returns the squares doubly attacked by pawns of the /// given color from the squares in the given bitboard. @@ -188,45 +197,65 @@ constexpr Bitboard pawn_double_attacks_bb(Bitboard b) { /// adjacent_files_bb() returns a bitboard representing all the squares on the -/// adjacent files of the given one. +/// adjacent files of a given square. -inline Bitboard adjacent_files_bb(Square s) { +constexpr Bitboard adjacent_files_bb(Square s) { return shift(file_bb(s)) | shift(file_bb(s)); } -/// between_bb() returns squares that are linearly between the given squares -/// If the given squares are not on a same file/rank/diagonal, return 0. +/// line_bb() returns a bitboard representing an entire line (from board edge +/// to board edge) that intersects the two given squares. If the given squares +/// are not on a same file/rank/diagonal, the function returns 0. For instance, +/// line_bb(SQ_C4, SQ_F7) will return a bitboard with the A2-G8 diagonal. + +inline Bitboard line_bb(Square s1, Square s2) { + + assert(is_ok(s1) && is_ok(s2)); + + return LineBB[s1][s2]; +} + + +/// between_bb(s1, s2) returns a bitboard representing the squares in the semi-open +/// segment between the squares s1 and s2 (excluding s1 but including s2). If the +/// given squares are not on a same file/rank/diagonal, it returns s2. For instance, +/// between_bb(SQ_C4, SQ_F7) will return a bitboard with squares D5, E6 and F7, but +/// between_bb(SQ_E6, SQ_F8) will return a bitboard with the square F8. This trick +/// allows to generate non-king evasion moves faster: the defending piece must either +/// interpose itself to cover the check or capture the checking piece. inline Bitboard between_bb(Square s1, Square s2) { - return LineBB[s1][s2] & ( (AllSquares << (s1 + (s1 < s2))) - ^(AllSquares << (s2 + !(s1 < s2)))); + + assert(is_ok(s1) && is_ok(s2)); + + return BetweenBB[s1][s2]; } -/// forward_ranks_bb() returns a bitboard representing the squares on the ranks -/// in front of the given one, from the point of view of the given color. For instance, +/// forward_ranks_bb() returns a bitboard representing the squares on the ranks in +/// front of the given one, from the point of view of the given color. For instance, /// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2. -inline Bitboard forward_ranks_bb(Color c, Square s) { - return c == WHITE ? ~Rank1BB << 8 * (rank_of(s) - RANK_1) - : ~Rank8BB >> 8 * (RANK_8 - rank_of(s)); +constexpr Bitboard forward_ranks_bb(Color c, Square s) { + return c == WHITE ? ~Rank1BB << 8 * relative_rank(WHITE, s) + : ~Rank8BB >> 8 * relative_rank(BLACK, s); } /// forward_file_bb() returns a bitboard representing all the squares along the /// line in front of the given one, from the point of view of the given color. -inline Bitboard forward_file_bb(Color c, Square s) { +constexpr Bitboard forward_file_bb(Color c, Square s) { return forward_ranks_bb(c, s) & file_bb(s); } /// pawn_attack_span() returns a bitboard representing all the squares that can -/// be attacked by a pawn of the given color when it moves along its file, -/// starting from the given square. +/// be attacked by a pawn of the given color when it moves along its file, starting +/// from the given square. -inline Bitboard pawn_attack_span(Color c, Square s) { +constexpr Bitboard pawn_attack_span(Color c, Square s) { return forward_ranks_bb(c, s) & adjacent_files_bb(s); } @@ -234,8 +263,8 @@ inline Bitboard pawn_attack_span(Color c, Square s) { /// passed_pawn_span() returns a bitboard which can be used to test if a pawn of /// the given color and on the given square is a passed pawn. -inline Bitboard passed_pawn_span(Color c, Square s) { - return forward_ranks_bb(c, s) & (adjacent_files_bb(s) | file_bb(s)); +constexpr Bitboard passed_pawn_span(Color c, Square s) { + return pawn_attack_span(c, s) | forward_file_bb(c, s); } @@ -243,7 +272,7 @@ inline Bitboard passed_pawn_span(Color c, Square s) { /// straight or on a diagonal line. inline bool aligned(Square s1, Square s2, Square s3) { - return LineBB[s1][s2] & s3; + return line_bb(s1, s2) & s3; } @@ -255,23 +284,43 @@ template<> inline int distance(Square x, Square y) { return std::abs(file_ template<> inline int distance(Square x, Square y) { return std::abs(rank_of(x) - rank_of(y)); } template<> inline int distance(Square x, Square y) { return SquareDistance[x][y]; } -template constexpr const T& clamp(const T& v, const T& lo, const T& hi) { - return v < lo ? lo : v > hi ? hi : v; +inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } +inline int edge_distance(Rank r) { return std::min(r, Rank(RANK_8 - r)); } + + +/// attacks_bb(Square) returns the pseudo attacks of the give piece type +/// assuming an empty board. + +template +inline Bitboard attacks_bb(Square s) { + + assert((Pt != PAWN) && (is_ok(s))); + + return PseudoAttacks[Pt][s]; } -/// attacks_bb() returns a bitboard representing all the squares attacked by a -/// piece of type Pt (bishop or rook) placed on 's'. + +/// attacks_bb(Square, Bitboard) returns the attacks by the given piece +/// assuming the board is occupied according to the passed Bitboard. +/// Sliding piece attacks do not continue passed an occupied square. template inline Bitboard attacks_bb(Square s, Bitboard occupied) { - const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s]; - return m.attacks[m.index(occupied)]; + assert((Pt != PAWN) && (is_ok(s))); + + switch (Pt) + { + case BISHOP: return BishopMagics[s].attacks[BishopMagics[s].index(occupied)]; + case ROOK : return RookMagics[s].attacks[ RookMagics[s].index(occupied)]; + case QUEEN : return attacks_bb(s, occupied) | attacks_bb(s, occupied); + default : return PseudoAttacks[Pt][s]; + } } inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) { - assert(pt != PAWN); + assert((pt != PAWN) && (is_ok(s))); switch (pt) { @@ -372,19 +421,31 @@ inline Square msb(Bitboard b) { #endif +/// least_significant_square_bb() returns the bitboard of the least significant +/// square of a non-zero bitboard. It is equivalent to square_bb(lsb(bb)). + +inline Bitboard least_significant_square_bb(Bitboard b) { + assert(b); + return b & -b; +} /// pop_lsb() finds and clears the least significant bit in a non-zero bitboard -inline Square pop_lsb(Bitboard* b) { - const Square s = lsb(*b); - *b &= *b - 1; +inline Square pop_lsb(Bitboard& b) { + assert(b); + const Square s = lsb(b); + b &= b - 1; return s; } -/// frontmost_sq() returns the most advanced square for the given color +/// frontmost_sq() returns the most advanced square for the given color, +/// requires a non-zero bitboard. inline Square frontmost_sq(Color c, Bitboard b) { + assert(b); return c == WHITE ? msb(b) : lsb(b); } +} // namespace Stockfish + #endif // #ifndef BITBOARD_H_INCLUDED