mirror of
https://github.com/sockspls/badfish
synced 2025-04-30 08:43:09 +00:00
c858990377
Adding a clamp function makes some of these range limitations a bit prettier and removes some #include's. STC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 28117 W: 6300 L: 6191 D: 15626 http://tests.stockfishchess.org/tests/view/5c9aa1df0ebc5925cfff8fcc Non functional change.
385 lines
11 KiB
C++
385 lines
11 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
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Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef BITBOARD_H_INCLUDED
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#define BITBOARD_H_INCLUDED
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#include <string>
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#include "types.h"
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namespace Bitbases {
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void init();
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bool probe(Square wksq, Square wpsq, Square bksq, Color us);
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}
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namespace Bitboards {
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void init();
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const std::string pretty(Bitboard b);
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}
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constexpr Bitboard AllSquares = ~Bitboard(0);
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constexpr Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
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constexpr Bitboard FileABB = 0x0101010101010101ULL;
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constexpr Bitboard FileBBB = FileABB << 1;
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constexpr Bitboard FileCBB = FileABB << 2;
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constexpr Bitboard FileDBB = FileABB << 3;
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constexpr Bitboard FileEBB = FileABB << 4;
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constexpr Bitboard FileFBB = FileABB << 5;
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constexpr Bitboard FileGBB = FileABB << 6;
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constexpr Bitboard FileHBB = FileABB << 7;
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constexpr Bitboard Rank1BB = 0xFF;
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constexpr Bitboard Rank2BB = Rank1BB << (8 * 1);
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constexpr Bitboard Rank3BB = Rank1BB << (8 * 2);
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constexpr Bitboard Rank4BB = Rank1BB << (8 * 3);
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constexpr Bitboard Rank5BB = Rank1BB << (8 * 4);
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constexpr Bitboard Rank6BB = Rank1BB << (8 * 5);
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constexpr Bitboard Rank7BB = Rank1BB << (8 * 6);
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constexpr Bitboard Rank8BB = Rank1BB << (8 * 7);
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constexpr Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
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constexpr Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
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constexpr Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
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constexpr Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
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extern uint8_t PopCnt16[1 << 16];
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extern uint8_t SquareDistance[SQUARE_NB][SQUARE_NB];
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extern Bitboard SquareBB[SQUARE_NB];
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extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
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extern Bitboard LineBB[SQUARE_NB][SQUARE_NB];
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extern Bitboard DistanceRingBB[SQUARE_NB][8];
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extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];
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extern Bitboard PawnAttacks[COLOR_NB][SQUARE_NB];
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extern Bitboard KingFlank[FILE_NB];
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/// Magic holds all magic bitboards relevant data for a single square
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struct Magic {
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Bitboard mask;
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Bitboard magic;
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Bitboard* attacks;
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unsigned shift;
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// Compute the attack's index using the 'magic bitboards' approach
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unsigned index(Bitboard occupied) const {
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if (HasPext)
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return unsigned(pext(occupied, mask));
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if (Is64Bit)
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return unsigned(((occupied & mask) * magic) >> shift);
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unsigned lo = unsigned(occupied) & unsigned(mask);
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unsigned hi = unsigned(occupied >> 32) & unsigned(mask >> 32);
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return (lo * unsigned(magic) ^ hi * unsigned(magic >> 32)) >> shift;
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}
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};
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extern Magic RookMagics[SQUARE_NB];
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extern Magic BishopMagics[SQUARE_NB];
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/// Overloads of bitwise operators between a Bitboard and a Square for testing
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/// whether a given bit is set in a bitboard, and for setting and clearing bits.
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inline Bitboard square_bb(Square s) {
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assert(s >= SQ_A1 && s <= SQ_H8);
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return SquareBB[s];
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}
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inline Bitboard operator&( Bitboard b, Square s) { return b & square_bb(s); }
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inline Bitboard operator|( Bitboard b, Square s) { return b | square_bb(s); }
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inline Bitboard operator^( Bitboard b, Square s) { return b ^ square_bb(s); }
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inline Bitboard& operator|=(Bitboard& b, Square s) { return b |= square_bb(s); }
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inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= square_bb(s); }
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constexpr bool more_than_one(Bitboard b) {
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return b & (b - 1);
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}
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inline bool opposite_colors(Square s1, Square s2) {
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return bool(DarkSquares & s1) != bool(DarkSquares & s2);
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}
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/// rank_bb() and file_bb() return a bitboard representing all the squares on
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/// the given file or rank.
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inline Bitboard rank_bb(Rank r) {
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return Rank1BB << (8 * r);
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}
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inline Bitboard rank_bb(Square s) {
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return rank_bb(rank_of(s));
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}
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inline Bitboard file_bb(File f) {
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return FileABB << f;
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}
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inline Bitboard file_bb(Square s) {
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return file_bb(file_of(s));
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}
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/// shift() moves a bitboard one step along direction D
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template<Direction D>
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constexpr Bitboard shift(Bitboard b) {
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return D == NORTH ? b << 8 : D == SOUTH ? b >> 8
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: D == EAST ? (b & ~FileHBB) << 1 : D == WEST ? (b & ~FileABB) >> 1
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: D == NORTH_EAST ? (b & ~FileHBB) << 9 : D == NORTH_WEST ? (b & ~FileABB) << 7
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: D == SOUTH_EAST ? (b & ~FileHBB) >> 7 : D == SOUTH_WEST ? (b & ~FileABB) >> 9
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: 0;
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}
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/// pawn_attacks_bb() returns the squares attacked by pawns of the given color
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/// from the squares in the given bitboard.
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template<Color C>
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constexpr Bitboard pawn_attacks_bb(Bitboard b) {
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return C == WHITE ? shift<NORTH_WEST>(b) | shift<NORTH_EAST>(b)
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: shift<SOUTH_WEST>(b) | shift<SOUTH_EAST>(b);
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}
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/// pawn_double_attacks_bb() returns the squares doubly attacked by pawns of the
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/// given color from the squares in the given bitboard.
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template<Color C>
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constexpr Bitboard pawn_double_attacks_bb(Bitboard b) {
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return C == WHITE ? shift<NORTH_WEST>(b) & shift<NORTH_EAST>(b)
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: shift<SOUTH_WEST>(b) & shift<SOUTH_EAST>(b);
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}
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/// adjacent_files_bb() returns a bitboard representing all the squares on the
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/// adjacent files of the given one.
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inline Bitboard adjacent_files_bb(File f) {
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return shift<EAST>(file_bb(f)) | shift<WEST>(file_bb(f));
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}
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/// between_bb() returns a bitboard representing all the squares between the two
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/// given ones. For instance, between_bb(SQ_C4, SQ_F7) returns a bitboard with
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/// the bits for square d5 and e6 set. If s1 and s2 are not on the same rank,
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/// file or diagonal, 0 is returned.
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inline Bitboard between_bb(Square s1, Square s2) {
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return BetweenBB[s1][s2];
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}
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/// forward_ranks_bb() returns a bitboard representing the squares on the ranks
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/// in front of the given one, from the point of view of the given color. For instance,
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/// forward_ranks_bb(BLACK, SQ_D3) will return the 16 squares on ranks 1 and 2.
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inline Bitboard forward_ranks_bb(Color c, Square s) {
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return c == WHITE ? ~Rank1BB << 8 * (rank_of(s) - RANK_1)
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: ~Rank8BB >> 8 * (RANK_8 - rank_of(s));
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}
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/// forward_file_bb() returns a bitboard representing all the squares along the
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/// line in front of the given one, from the point of view of the given color.
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inline Bitboard forward_file_bb(Color c, Square s) {
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return forward_ranks_bb(c, s) & file_bb(s);
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}
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/// pawn_attack_span() returns a bitboard representing all the squares that can
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/// be attacked by a pawn of the given color when it moves along its file,
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/// starting from the given square.
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inline Bitboard pawn_attack_span(Color c, Square s) {
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return forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s));
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}
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/// passed_pawn_span() returns a bitboard which can be used to test if a pawn of
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/// the given color and on the given square is a passed pawn.
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inline Bitboard passed_pawn_span(Color c, Square s) {
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return forward_ranks_bb(c, s) & (adjacent_files_bb(file_of(s)) | file_bb(s));
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}
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/// aligned() returns true if the squares s1, s2 and s3 are aligned either on a
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/// straight or on a diagonal line.
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inline bool aligned(Square s1, Square s2, Square s3) {
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return LineBB[s1][s2] & s3;
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}
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/// distance() functions return the distance between x and y, defined as the
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/// number of steps for a king in x to reach y. Works with squares, ranks, files.
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template<typename T> inline int distance(T x, T y) { return std::abs(x - y); }
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template<> inline int distance<Square>(Square x, Square y) { return SquareDistance[x][y]; }
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template<typename T1, typename T2> inline int distance(T2 x, T2 y);
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template<> inline int distance<File>(Square x, Square y) { return distance(file_of(x), file_of(y)); }
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template<> inline int distance<Rank>(Square x, Square y) { return distance(rank_of(x), rank_of(y)); }
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template<class T> constexpr const T& clamp(const T& v, const T& lo, const T& hi) {
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return v < lo ? lo : v > hi ? hi : v;
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}
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/// attacks_bb() returns a bitboard representing all the squares attacked by a
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/// piece of type Pt (bishop or rook) placed on 's'.
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template<PieceType Pt>
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inline Bitboard attacks_bb(Square s, Bitboard occupied) {
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const Magic& m = Pt == ROOK ? RookMagics[s] : BishopMagics[s];
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return m.attacks[m.index(occupied)];
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}
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inline Bitboard attacks_bb(PieceType pt, Square s, Bitboard occupied) {
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assert(pt != PAWN);
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switch (pt)
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{
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case BISHOP: return attacks_bb<BISHOP>(s, occupied);
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case ROOK : return attacks_bb< ROOK>(s, occupied);
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case QUEEN : return attacks_bb<BISHOP>(s, occupied) | attacks_bb<ROOK>(s, occupied);
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default : return PseudoAttacks[pt][s];
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}
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}
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/// popcount() counts the number of non-zero bits in a bitboard
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inline int popcount(Bitboard b) {
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#ifndef USE_POPCNT
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union { Bitboard bb; uint16_t u[4]; } v = { b };
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return PopCnt16[v.u[0]] + PopCnt16[v.u[1]] + PopCnt16[v.u[2]] + PopCnt16[v.u[3]];
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#elif defined(_MSC_VER) || defined(__INTEL_COMPILER)
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return (int)_mm_popcnt_u64(b);
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#else // Assumed gcc or compatible compiler
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return __builtin_popcountll(b);
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#endif
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}
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/// lsb() and msb() return the least/most significant bit in a non-zero bitboard
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#if defined(__GNUC__) // GCC, Clang, ICC
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inline Square lsb(Bitboard b) {
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assert(b);
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return Square(__builtin_ctzll(b));
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}
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inline Square msb(Bitboard b) {
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assert(b);
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return Square(63 ^ __builtin_clzll(b));
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}
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#elif defined(_MSC_VER) // MSVC
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#ifdef _WIN64 // MSVC, WIN64
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inline Square lsb(Bitboard b) {
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assert(b);
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unsigned long idx;
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_BitScanForward64(&idx, b);
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return (Square) idx;
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}
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inline Square msb(Bitboard b) {
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assert(b);
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unsigned long idx;
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_BitScanReverse64(&idx, b);
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return (Square) idx;
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}
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#else // MSVC, WIN32
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inline Square lsb(Bitboard b) {
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assert(b);
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unsigned long idx;
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if (b & 0xffffffff) {
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_BitScanForward(&idx, int32_t(b));
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return Square(idx);
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} else {
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_BitScanForward(&idx, int32_t(b >> 32));
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return Square(idx + 32);
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}
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}
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inline Square msb(Bitboard b) {
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assert(b);
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unsigned long idx;
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if (b >> 32) {
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_BitScanReverse(&idx, int32_t(b >> 32));
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return Square(idx + 32);
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} else {
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_BitScanReverse(&idx, int32_t(b));
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return Square(idx);
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}
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}
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#endif
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#else // Compiler is neither GCC nor MSVC compatible
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#error "Compiler not supported."
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#endif
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/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard
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inline Square pop_lsb(Bitboard* b) {
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const Square s = lsb(*b);
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*b &= *b - 1;
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return s;
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}
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/// frontmost_sq() and backmost_sq() return the square corresponding to the
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/// most/least advanced bit relative to the given color.
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inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
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inline Square backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(b); }
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#endif // #ifndef BITBOARD_H_INCLUDED
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