template<PieceType>
MoveStack* generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*);
- MoveStack* generate_piece_checks_king(const Position&, Square, Bitboard, Square, MoveStack*);
template<PieceType>
MoveStack* generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*);
mlist = generate_piece_checks<QUEEN>(pos, b, dc, ksq, mlist);
// Hopefully we always have a king ;-)
- mlist = generate_piece_checks_king(pos, pos.king_square(us), dc, ksq, mlist);
+ mlist = generate_piece_checks<KING>(pos, pos.kings(us), dc, ksq, mlist);
// Castling moves that give check. Very rare but nice to have!
if ( pos.can_castle_queenside(us)
assert(pos.piece_on(ksq) == king_of_color(us));
- // Generate evasions for king
- Bitboard b1 = pos.piece_attacks<KING>(ksq) & ~pos.pieces_of_color(us);
+ // The bitboard of occupied pieces without our king
Bitboard b2 = pos.occupied_squares();
clear_bit(&b2, ksq);
+ // Find squares attacked by slider checkers, we will
+ // remove them from king evasions set so to avoid a couple
+ // of cycles in the slow king evasions legality check loop.
+ Bitboard checkers = pos.checkers();
+ Bitboard checkersAttacks = EmptyBoardBB;
+ Bitboard b = checkers & (pos.queens() | pos.bishops());
+ while (b)
+ {
+ from = pop_1st_bit(&b);
+ checkersAttacks |= bishop_attacks_bb(from, b2);
+ }
+
+ b = checkers & (pos.queens() | pos.rooks());
+ while (b)
+ {
+ from = pop_1st_bit(&b);
+ checkersAttacks |= rook_attacks_bb(from, b2);
+ }
+
+ // Generate evasions for king
+ Bitboard b1 = pos.piece_attacks<KING>(ksq) & ~pos.pieces_of_color(us) & ~checkersAttacks;
while (b1)
{
- to = pop_1st_bit(&b1);
-
- // Make sure 'to' is not attacked by the other side. This is a bit ugly,
- // because we can't use Position::square_is_attacked. Instead we use
- // the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
- // b2 (the occupied squares with the king removed) in order to test whether
- // the king will remain in check on the destination square.
- if (!( (pos.piece_attacks<KNIGHT>(to) & pos.knights(them))
- || (pos.pawn_attacks(us, to) & pos.pawns(them))
- || (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
- || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
- || (pos.piece_attacks<KING>(to) & pos.kings(them))))
-
- (*mlist++).move = make_move(ksq, to);
+ to = pop_1st_bit(&b1);
+
+ // Make sure 'to' is not attacked by the other side. This is a bit ugly,
+ // because we can't use Position::square_is_attacked. Instead we use
+ // the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
+ // b2 (the occupied squares with the king removed) in order to test whether
+ // the king will remain in check on the destination square.
+ if (!( (pos.piece_attacks<KNIGHT>(to) & pos.knights(them))
+ || (pos.pawn_attacks(us, to) & pos.pawns(them))
+ || (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
+ || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
+ || (pos.piece_attacks<KING>(to) & pos.kings(them))))
+ (*mlist++).move = make_move(ksq, to);
}
// Generate evasions for other pieces only if not double check. We use a
// simple bit twiddling hack here rather than calling count_1s in order to
// save some time (we know that pos.checkers() has at most two nonzero bits).
- Bitboard checkers = pos.checkers();
-
if (!(checkers & (checkers - 1))) // Only one bit set?
{
Square checksq = first_1(checkers);
template<Color Us, Color Them, Bitboard TRank8BB, Bitboard TRank3BB, SquareDelta TDELTA_N>
MoveStack* do_generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist)
{
- // Pawn moves which give discovered check. This is possible only if the
+ // Pawn moves which gives discovered check. This is possible only if the
// pawn is not on the same file as the enemy king, because we don't
// generate captures.
Bitboard empty = pos.empty_squares();
{
Square from = pop_1st_bit(&b);
Bitboard bb = pos.piece_attacks<Piece>(from) & pos.empty_squares();
+ if (Piece == KING)
+ bb &= ~QueenPseudoAttacks[ksq];
+
SERIALIZE_MOVES(bb);
}
+
+ if (Piece == KING)
+ return mlist;
+
// Direct checks
b = target & ~dc;
Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
return mlist;
}
- MoveStack* generate_piece_checks_king(const Position& pos, Square from, Bitboard dc,
- Square ksq, MoveStack* mlist) {
- if (bit_is_set(dc, from))
- {
- Bitboard b = pos.piece_attacks<KING>(from)
- & pos.empty_squares()
- & ~QueenPseudoAttacks[ksq];
- SERIALIZE_MOVES(b);
- }
- return mlist;
- }
-
-
template<Color Us, Rank TRANK_8, Bitboard TRank3BB, SquareDelta TDELTA_N>
MoveStack* do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned,
Bitboard blockSquares, MoveStack* mlist) {
File rookFile = (side == QUEEN_SIDE ? FILE_D : FILE_F);
Color us = pos.side_to_move();
Square ksq = pos.king_square(us);
- Bitboard occ = pos.occupied_squares(), oppKingBB = EmptyBoardBB;
+ Bitboard occ = pos.occupied_squares();
- set_bit(&oppKingBB, pos.king_square(opposite_color(us)));
clear_bit(&occ, ksq); // Remove our king from the board
Square rsq = make_square(rookFile, square_rank(ksq));
- return (rook_attacks_bb(rsq, occ) & oppKingBB);
+ return bit_is_set(rook_attacks_bb(rsq, occ), pos.king_square(opposite_color(us)));
}
}
projects / stockfish / blobdiff