X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fbitboard.h;h=dee73b4b3f70285016e601032cd4ed65738f65a8;hb=fce4cc1829f25fd52c5dd637ab54d867eec065fb;hp=f1d14603687fd19ae0d975799154d15ac8058a66;hpb=47be966d3028ca9b5c4d095f266663eb205c0c07;p=stockfish diff --git a/src/bitboard.h b/src/bitboard.h index f1d14603..dee73b4b 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) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2004-2023 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 @@ -21,26 +19,23 @@ #ifndef BITBOARD_H_INCLUDED #define BITBOARD_H_INCLUDED +#include +#include +#include +#include +#include #include #include "types.h" -namespace Bitbases { - -void init(); -bool probe(Square wksq, Square wpsq, Square bksq, Color us); - -} +namespace Stockfish { namespace Bitboards { void init(); -const std::string pretty(Bitboard b); - -} +std::string pretty(Bitboard b); -constexpr Bitboard AllSquares = ~Bitboard(0); -constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL; +} // namespace Stockfish::Bitboards constexpr Bitboard FileABB = 0x0101010101010101ULL; constexpr Bitboard FileBBB = FileABB << 1; @@ -60,21 +55,10 @@ constexpr Bitboard Rank6BB = Rank1BB << (8 * 5); constexpr Bitboard Rank7BB = Rank1BB << (8 * 6); constexpr Bitboard Rank8BB = Rank1BB << (8 * 7); -constexpr Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB; -constexpr Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB; -constexpr Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB; -constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB); - -constexpr Bitboard KingFlank[FILE_NB] = { - QueenSide ^ FileDBB, QueenSide, QueenSide, - CenterFiles, CenterFiles, - KingSide, KingSide, KingSide ^ FileEBB -}; - 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 +90,11 @@ extern Magic RookMagics[SQUARE_NB]; extern Magic BishopMagics[SQUARE_NB]; inline Bitboard square_bb(Square s) { - assert(s >= SQ_A1 && s <= SQ_H8); - return SquareBB[s]; + assert(is_ok(s)); + return (1ULL << 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. @@ -123,33 +108,29 @@ 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); } -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)); } @@ -176,74 +157,45 @@ constexpr Bitboard pawn_attacks_bb(Bitboard b) { : shift(b) | shift(b); } +inline Bitboard pawn_attacks_bb(Color c, Square s) { -/// pawn_double_attacks_bb() returns the squares doubly attacked by pawns of the -/// given color from the squares in the given bitboard. - -template -constexpr Bitboard pawn_double_attacks_bb(Bitboard b) { - return C == WHITE ? shift(b) & shift(b) - : shift(b) & shift(b); -} - - -/// adjacent_files_bb() returns a bitboard representing all the squares on the -/// adjacent files of the given one. - -inline Bitboard adjacent_files_bb(Square s) { - return shift(file_bb(s)) | shift(file_bb(s)); + assert(is_ok(s)); + return PawnAttacks[c][s]; } +/// 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. -/// 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. - -inline Bitboard between_bb(Square s1, Square s2) { - Bitboard b = LineBB[s1][s2] & ((AllSquares << s1) ^ (AllSquares << s2)); - return b & (b - 1); //exclude lsb -} +inline Bitboard line_bb(Square s1, Square s2) { + assert(is_ok(s1) && is_ok(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(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)); + return LineBB[s1][s2]; } -/// 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) { - 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. - -inline Bitboard pawn_attack_span(Color c, Square s) { - return forward_ranks_bb(c, s) & adjacent_files_bb(s); -} +/// 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) { -/// 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. + assert(is_ok(s1) && is_ok(s2)); -inline Bitboard passed_pawn_span(Color c, Square s) { - return forward_ranks_bb(c, s) & (adjacent_files_bb(s) | file_bb(s)); + return BetweenBB[s1][s2]; } - /// aligned() returns true if the squares s1, s2 and s3 are aligned either on a /// 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; } @@ -255,22 +207,41 @@ 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]; } -inline File edge_distance(File f) { return std::min(f, File(FILE_H - f)); } -inline Rank edge_distance(Rank r) { return std::min(r, Rank(RANK_8 - r)); } +inline int edge_distance(File f) { return std::min(f, File(FILE_H - f)); } -/// 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) 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(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) { @@ -291,9 +262,9 @@ inline int popcount(Bitboard b) { union { Bitboard bb; uint16_t u[4]; } v = { b }; return PopCnt16[v.u[0]] + PopCnt16[v.u[1]] + PopCnt16[v.u[2]] + PopCnt16[v.u[3]]; -#elif defined(_MSC_VER) || defined(__INTEL_COMPILER) +#elif defined(_MSC_VER) - return (int)_mm_popcnt_u64(b); + return int(_mm_popcnt_u64(b)); #else // Assumed gcc or compatible compiler @@ -305,7 +276,7 @@ inline int popcount(Bitboard b) { /// lsb() and msb() return the least/most significant bit in a non-zero bitboard -#if defined(__GNUC__) // GCC, Clang, ICC +#if defined(__GNUC__) // GCC, Clang, ICX inline Square lsb(Bitboard b) { assert(b); @@ -371,19 +342,23 @@ 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 -inline Square frontmost_sq(Color c, Bitboard b) { - return c == WHITE ? msb(b) : lsb(b); -} +} // namespace Stockfish #endif // #ifndef BITBOARD_H_INCLUDED