EVASION
};
- // Functions
- bool castling_is_check(const Position&, CastlingSide);
-
// Helper templates
template<CastlingSide Side>
MoveStack* generate_castle_moves(const Position&, MoveStack*);
: generate_pawn_moves<BLACK, Type>(p, m));
}
- // Template generate_piece_checks with specializations
+ // Templates for non-capture checks generation
+
+ template<PieceType Piece>
+ MoveStack* generate_discovered_checks(const Position& pos, Square from, MoveStack* mlist);
+
template<PieceType>
- MoveStack* generate_piece_checks(const Position&, MoveStack*, Color, Bitboard, Square);
+ MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square);
template<>
- inline MoveStack* generate_
piece_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
+ inline MoveStack* generate_
direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
return (us == WHITE ? generate_pawn_moves<WHITE, CHECK>(p, m, dc, ksq)
: generate_pawn_moves<BLACK, CHECK>(p, m, dc, ksq));
assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
- // Pieces moves
- mlist = generate_piece_checks<PAWN>(pos, mlist, us, dc, ksq);
- mlist = generate_piece_checks<KNIGHT>(pos, mlist, us, dc, ksq);
- mlist = generate_piece_checks<BISHOP>(pos, mlist, us, dc, ksq);
- mlist = generate_piece_checks<ROOK>(pos, mlist, us, dc, ksq);
- mlist = generate_piece_checks<QUEEN>(pos, mlist, us, dc, ksq);
- mlist = generate_piece_checks<KING>(pos, mlist, us, dc, ksq);
-
- // Castling moves that give check. Very rare but nice to have!
- if ( pos.can_castle_queenside(us)
- && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_D)
- && castling_is_check(pos, QUEEN_SIDE))
- mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist);
-
- if ( pos.can_castle_kingside(us)
- && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_F)
- && castling_is_check(pos, KING_SIDE))
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
+ // Discovered non-capture checks
+ Bitboard b = dc;
+ while (b)
+ {
+ Square from = pop_1st_bit(&b);
+ switch (pos.type_of_piece_on(from))
+ {
+ case PAWN: /* Will be generated togheter with pawns direct checks */ break;
+ case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, from, mlist); break;
+ case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, from, mlist); break;
+ case ROOK: mlist = generate_discovered_checks<ROOK>(pos, from, mlist); break;
+ case KING: mlist = generate_discovered_checks<KING>(pos, from, mlist); break;
+ default: assert(false); break;
+ }
+ }
- return mlist;
+ // Direct non-capture checks
+ mlist = generate_direct_checks<PAWN>(pos, mlist, us, dc, ksq);
+ mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, dc, ksq);
+ mlist = generate_direct_checks<BISHOP>(pos, mlist, us, dc, ksq);
+ mlist = generate_direct_checks<ROOK>(pos, mlist, us, dc, ksq);
+ return generate_direct_checks<QUEEN>(pos, mlist, us, dc, ksq);
}
// 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).
- if (!(checkers & (checkers - 1))) // Only one bit set?
- {
- Square checksq = first_1(checkers);
+ if (checkers & (checkers - 1)) // Two bits set?
+ return mlist;
- assert(pos.color_of_piece_on(checksq) == them);
+ Square checksq = first_1(checkers);
+ Bitboard target = squares_between(checksq, ksq);
- // Generate captures of the checking piece
+ assert(pos.color_of_piece_on(checksq) == them);
- // Pawn captures
- b1 = pos.attacks_from<PAWN>(checksq, them) & pos.pieces(PAWN, us) & ~pinned;
- while (b1)
+ // Pawn captures
+ b1 = pos.attacks_from<PAWN>(checksq, them) & pos.pieces(PAWN, us) & ~pinned;
+ while (b1)
+ {
+ from = pop_1st_bit(&b1);
+ if (relative_rank(us, checksq) == RANK_8)
{
- from = pop_1st_bit(&b1);
- if (relative_rank(us, checksq) == RANK_8)
- {
- (*mlist++).move = make_promotion_move(from, checksq, QUEEN);
- (*mlist++).move = make_promotion_move(from, checksq, ROOK);
- (*mlist++).move = make_promotion_move(from, checksq, BISHOP);
- (*mlist++).move = make_promotion_move(from, checksq, KNIGHT);
- } else
- (*mlist++).move = make_move(from, checksq);
- }
+ (*mlist++).move = make_promotion_move(from, checksq, QUEEN);
+ (*mlist++).move = make_promotion_move(from, checksq, ROOK);
+ (*mlist++).move = make_promotion_move(from, checksq, BISHOP);
+ (*mlist++).move = make_promotion_move(from, checksq, KNIGHT);
+ } else
+ (*mlist++).move = make_move(from, checksq);
+ }
- // Pieces captures
- b1 = ( (pos.attacks_from<KNIGHT>(checksq) & pos.pieces(KNIGHT, us))
- | (pos.attacks_from<BISHOP>(checksq) & pos.pieces(BISHOP, QUEEN, us))
- | (pos.attacks_from<ROOK>(checksq) & pos.pieces(ROOK, QUEEN, us)) ) & ~pinned;
+ // Pawn blocking evasions (possible only if the checking piece is a slider)
+ if (sliderAttacks)
+ mlist = generate_piece_evasions<PAWN>(pos, mlist, us, target, pinned);
+
+ // Add the checking piece to the target squares
+ target |= checkers;
+
+ // Captures and blocking evasions for the other pieces
+ mlist = generate_piece_evasions<KNIGHT>(pos, mlist, us, target, pinned);
+ mlist = generate_piece_evasions<BISHOP>(pos, mlist, us, target, pinned);
+ mlist = generate_piece_evasions<ROOK>(pos, mlist, us, target, pinned);
+ mlist = generate_piece_evasions<QUEEN>(pos, mlist, us, target, pinned);
+
+ // Finally, the special case of en passant captures. An en passant
+ // capture can only be a check evasion if the check is not a discovered
+ // check. If pos.ep_square() is set, the last move made must have been
+ // a double pawn push. If, furthermore, the checking piece is a pawn,
+ // an en passant check evasion may be possible.
+ if (pos.ep_square() != SQ_NONE && (checkers & pos.pieces(PAWN, them)))
+ {
+ to = pos.ep_square();
+ b1 = pos.attacks_from<PAWN>(to, them) & pos.pieces(PAWN, us);
+
+ // The checking pawn cannot be a discovered (bishop) check candidate
+ // otherwise we were in check also before last double push move.
+ assert(!bit_is_set(pos.discovered_check_candidates(them), checksq));
+ assert(count_1s(b1) == 1 || count_1s(b1) == 2);
+ b1 &= ~pinned;
while (b1)
{
from = pop_1st_bit(&b1);
- (*mlist++).move = make_move(from, checksq);
- }
-
- // Blocking check evasions are possible only if the checking piece is a slider
- if (sliderAttacks)
- {
- Bitboard blockSquares = squares_between(checksq, ksq);
-
- assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
-
- if (blockSquares)
- {
- mlist = generate_piece_evasions<PAWN>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_evasions<KNIGHT>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_evasions<BISHOP>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_evasions<ROOK>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_evasions<QUEEN>(pos, mlist, us, blockSquares, pinned);
- }
- }
-
- // Finally, the special case of en passant captures. An en passant
- // capture can only be a check evasion if the check is not a discovered
- // check. If pos.ep_square() is set, the last move made must have been
- // a double pawn push. If, furthermore, the checking piece is a pawn,
- // an en passant check evasion may be possible.
- if (pos.ep_square() != SQ_NONE && (checkers & pos.pieces(PAWN, them)))
- {
- to = pos.ep_square();
- b1 = pos.attacks_from<PAWN>(to, them) & pos.pieces(PAWN, us);
-
- // The checking pawn cannot be a discovered (bishop) check candidate
- // otherwise we were in check also before last double push move.
- assert(!bit_is_set(pos.discovered_check_candidates(them), checksq));
- assert(count_1s(b1) == 1 || count_1s(b1) == 2);
-
- b1 &= ~pinned;
- while (b1)
- {
- from = pop_1st_bit(&b1);
- // Move is always legal because checking pawn is not a discovered
- // check candidate and our capturing pawn has been already tested
- // against pinned pieces.
- (*mlist++).move = make_ep_move(from, to);
- }
+ // Move is always legal because checking pawn is not a discovered
+ // check candidate and our capturing pawn has been already tested
+ // against pinned pieces.
+ (*mlist++).move = make_ep_move(from, to);
}
}
return mlist;
// Single pawn pushes
b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
b2 = (Type == CHECK ? (b1 & pos.attacks_from<PAWN>(ksq, Them)) | dcPawns1 :
- (Type == EVASION ? b1 & blockSquares : b1));
+ (Type == EVASION ? b1 & blockSquares : b1));
SERIALIZE_MOVES_D(b2, -TDELTA_N);
// Double pawn pushes
b1 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & emptySquares;
b2 = (Type == CHECK ? (b1 & pos.attacks_from<PAWN>(ksq, Them)) | dcPawns2 :
- (Type == EVASION ? b1 & blockSquares : b1));
+ (Type == EVASION ? b1 & blockSquares : b1));
SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
}
else if (pos.ep_square() != SQ_NONE) // En passant captures
}
template<PieceType Piece>
- MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us,
+ MoveStack* generate_discovered_checks(const Position& pos, Square from, MoveStack* mlist) {
+
+ assert(Piece != QUEEN);
+
+ Bitboard b = pos.attacks_from<Piece>(from) & pos.empty_squares();
+ if (Piece == KING)
+ {
+ Square ksq = pos.king_square(opposite_color(pos.side_to_move()));
+ b &= ~QueenPseudoAttacks[ksq];
+ }
+ SERIALIZE_MOVES(b);
+ return mlist;
+ }
+
+ template<PieceType Piece>
+ MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
+ assert(Piece != KING);
- Bitboard target = pos.pieces(Piece, us);
+ Square from;
+ Bitboard checkSqs;
+ const Square* ptr = pos.piece_list_begin(us, Piece);
- // Discovered non-capture checks
- Bitboard b = target & dc;
+ if ((from = *ptr++) == SQ_NONE)
+ return mlist;
- assert(Piece != QUEEN || !b);
+ checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
- while (b)
+ do
{
- Square from = pop_1st_bit(&b);
- Bitboard bb = pos.attacks_from<Piece>(from) & pos.empty_squares();
- if (Piece == KING)
- bb &= ~QueenPseudoAttacks[ksq];
+ if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
+ || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
+ || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+ continue;
+ if (dc && bit_is_set(dc, from))
+ continue;
+
+ Bitboard bb = pos.attacks_from<Piece>(from) & checkSqs;
SERIALIZE_MOVES(bb);
- }
- // Direct non-capture checks
- b = target & ~dc;
- Bitboard checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
- if (Piece != KING && checkSqs)
- {
- while (b)
- {
- Square from = pop_1st_bit(&b);
- if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
-
- Bitboard bb = pos.attacks_from<Piece>(from) & checkSqs;
- SERIALIZE_MOVES(bb);
- }
- }
+ } while ((from = *ptr++) != SQ_NONE);
+
return mlist;
}
}
return mlist;
}
-
- bool castling_is_check(const Position& pos, CastlingSide side) {
-
- // After castling opponent king is attacked by the castled rook?
- 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();
-
- clear_bit(&occ, ksq); // Remove our king from the board
- Square rsq = make_square(rookFile, square_rank(ksq));
- return bit_is_set(rook_attacks_bb(rsq, occ), pos.king_square(opposite_color(us)));
- }
}
projects / stockfish / blobdiff