/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
+ 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
#ifndef BITBOARD_H_INCLUDED
#define BITBOARD_H_INCLUDED
+#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <cstdint>
+#include <cstdlib>
#include <string>
#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;
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];
inline Bitboard square_bb(Square s) {
assert(is_ok(s));
- return SquareBB[s];
+ return (1ULL << s);
}
}
-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.
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.
-
-template<Color C>
-constexpr Bitboard pawn_double_attacks_bb(Bitboard b) {
- return C == WHITE ? shift<NORTH_WEST>(b) & shift<NORTH_EAST>(b)
- : shift<SOUTH_WEST>(b) & shift<SOUTH_EAST>(b);
-}
-
-
-/// adjacent_files_bb() returns a bitboard representing all the squares on the
-/// adjacent files of a given square.
-
-constexpr Bitboard adjacent_files_bb(Square s) {
- return shift<EAST>(file_bb(s)) | shift<WEST>(file_bb(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,
inline Bitboard line_bb(Square s1, Square s2) {
assert(is_ok(s1) && is_ok(s2));
+
return LineBB[s1][s2];
}
-/// between_bb() returns a bitboard representing squares that are linearly
-/// between the two given squares (excluding the given squares). If the given
-/// squares are not on a same file/rank/diagonal, we return 0. For instance,
-/// between_bb(SQ_C4, SQ_F7) will return a bitboard with squares D5 and E6.
+/// 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) {
- Bitboard b = line_bb(s1, s2) & ((AllSquares << s1) ^ (AllSquares << s2));
- return b & (b - 1); //exclude lsb
-}
+ 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.
-
-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.
-
-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.
-
-constexpr Bitboard pawn_attack_span(Color c, Square s) {
- return forward_ranks_bb(c, s) & adjacent_files_bb(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.
-
-constexpr Bitboard passed_pawn_span(Color c, Square s) {
- return pawn_attack_span(c, s) | forward_file_bb(c, 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.
template<> inline int distance<Square>(Square x, Square y) { return SquareDistance[x][y]; }
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.
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
/// 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);
#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)).
-/// pop_lsb() finds and clears the least significant bit in a non-zero bitboard
-
-inline Square pop_lsb(Bitboard* b) {
- assert(*b);
- const Square s = lsb(*b);
- *b &= *b - 1;
- return s;
+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
-/// frontmost_sq() returns the most advanced square for the given color,
-/// requires a non-zero bitboard.
-inline Square frontmost_sq(Color c, Bitboard b) {
+inline Square pop_lsb(Bitboard& b) {
assert(b);
- return c == WHITE ? msb(b) : lsb(b);
+ const Square s = lsb(b);
+ b &= b - 1;
+ return s;
}
+} // namespace Stockfish
+
#endif // #ifndef BITBOARD_H_INCLUDED
projects / stockfish / blobdiff