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) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, 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
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];
}
inline Bitboard& operator|=(Bitboard& b, Square s) { return b |= square_bb(s); }
inline Bitboard& operator^=(Bitboard& b, Square s) { return b ^= square_bb(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, Bitboard b) { return b ^ s; }
+
+inline Bitboard operator|(Square s, Square s2) { return square_bb(s) | 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;
}
}
-/// shift() moves a bitboard one step along direction D
+/// shift() moves a bitboard one or two steps as specified by the direction D
template<Direction D>
constexpr Bitboard shift(Bitboard b) {
: shift<SOUTH_WEST>(b) | shift<SOUTH_EAST>(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.
return shift<EAST>(file_bb(s)) | shift<WEST>(file_bb(s));
}
+/// line_bb(Square, Square) returns a Bitboard representing an entire line
+/// (from board edge to board edge) that intersects the given squares.
+/// If the given squares are not on a same file/rank/diagonal, return 0.
+/// Ex. line_bb(SQ_C4, SQ_F7) returns 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() returns squares that are linearly between the given squares
+/// between_bb() returns a Bitboard representing squares that are linearly
+/// between the given squares (excluding the given squares).
/// If the given squares are not on a same file/rank/diagonal, return 0.
+/// Ex. between_bb(SQ_C4, SQ_F7) returns a bitboard with squares D5 and E6.
inline Bitboard between_bb(Square s1, Square s2) {
- return LineBB[s1][s2] & ( (AllSquares << (s1 + (s1 < s2)))
- ^(AllSquares << (s2 + !(s1 < s2))));
+ Bitboard b = line_bb(s1, s2) & ((AllSquares << s1) ^ (AllSquares << s2));
+ return b & (b - 1); //exclude lsb
}
/// 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 c == WHITE ? ~Rank1BB << 8 * relative_rank(WHITE, s)
+ : ~Rank8BB >> 8 * relative_rank(BLACK, 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;
}
template<> inline int distance<Rank>(Square x, Square y) { return std::abs(rank_of(x) - rank_of(y)); }
template<> inline int distance<Square>(Square x, Square y) { return SquareDistance[x][y]; }
-template<class T> 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)); }
+
+/// Return the target square bitboard if we do not step off the board, empty otherwise
+
+inline Bitboard safe_destination(Square s, int step)
+{
+ Square to = Square(s + step);
+ return is_ok(to) && distance(s, to) <= 2 ? square_bb(to) : Bitboard(0);
}
-/// 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<PieceType Pt>
+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<PieceType Pt>
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<BISHOP>(s, occupied) | attacks_bb<ROOK>(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)
{
/// 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;
}
-/// 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); }
+/// 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);
+}
#endif // #ifndef BITBOARD_H_INCLUDED
projects / stockfish / blobdiff