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];
}
+
/// 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.
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);
}
+/// Counts the occupation of the bitboard depending on the occupation of SQ_A1
+/// as in `b & (1ULL << SQ_A1) ? more_than_two(b) : more_than_one(b)`
+
+constexpr bool conditional_more_than_two(Bitboard b) {
+ return b & (b - 1) & (b - 2);
+}
+
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));
}
: 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.
/// adjacent_files_bb() returns a bitboard representing all the squares on the
-/// adjacent files of the given one.
+/// adjacent files of a given square.
-inline Bitboard adjacent_files_bb(Square s) {
+constexpr Bitboard adjacent_files_bb(Square s) {
return shift<EAST>(file_bb(s)) | shift<WEST>(file_bb(s));
}
-/// 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.
+/// 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.
+
+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.
inline Bitboard between_bb(Square s1, Square s2) {
- Bitboard b = LineBB[s1][s2] & ((AllSquares << s1) ^ (AllSquares << s2));
+ Bitboard b = line_bb(s1, s2) & ((AllSquares << s1) ^ (AllSquares << s2));
return b & (b - 1); //exclude lsb
}
/// 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));
+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.
-inline Bitboard forward_file_bb(Color c, Square s) {
+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.
+/// 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) {
+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.
-inline Bitboard passed_pawn_span(Color c, Square s) {
- return forward_ranks_bb(c, s) & (adjacent_files_bb(s) | file_bb(s));
+constexpr Bitboard passed_pawn_span(Color c, Square s) {
+ return pawn_attack_span(c, s) | forward_file_bb(c, 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]; }
+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() returns a bitboard representing all the squares attacked by a
-/// piece of type Pt (bishop or rook) placed on 's'.
+
+/// safe_destination() returns the bitboard of target square for the given step
+/// from the given square. If the step is off the board, returns empty bitboard.
+
+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(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
+/// 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);
}
projects / stockfish / blobdiff