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
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) | square_bb(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) {
/// adjacent_files_bb() returns a bitboard representing all the squares on the
/// adjacent files of the given one.
-inline Bitboard adjacent_files_bb(File f) {
- return shift<EAST>(file_bb(f)) | shift<WEST>(file_bb(f));
+inline Bitboard adjacent_files_bb(Square s) {
+ return shift<EAST>(file_bb(s)) | shift<WEST>(file_bb(s));
}
/// If the given squares are not on a same file/rank/diagonal, return 0.
inline Bitboard between_bb(Square s1, Square s2) {
- return LineBB[s1][s2] & ( (AllSquares << (s1 + (s1 < s2)))
- ^(AllSquares << (s2 + !(s1 < s2))));
+ Bitboard b = LineBB[s1][s2] & ((AllSquares << s1) ^ (AllSquares << s2));
+ return b & (b - 1); //exclude lsb
}
/// starting from the given square.
inline Bitboard pawn_attack_span(Color c, Square s) {
- return forward_ranks_bb(c, s) & adjacent_files_bb(file_of(s));
+ return forward_ranks_bb(c, s) & adjacent_files_bb(s);
}
/// 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(file_of(s)) | file_bb(s));
+ return forward_ranks_bb(c, s) & (adjacent_files_bb(s) | file_bb(s));
}
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 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)); }
/// attacks_bb() returns a bitboard representing all the squares attacked by a
/// piece of type Pt (bishop or rook) placed on 's'.
/// 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() and backmost_sq() return the most/least advanced square in
-/// the given bitboard relative to the given color.
-
-inline Square frontmost_sq(Color c, Bitboard b) { return c == WHITE ? msb(b) : lsb(b); }
-inline Square backmost_sq(Color c, Bitboard b) { return c == WHITE ? lsb(b) : msb(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