X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=12260e3b9dd99fd3b67bddce75dc9498bcd81499;hp=7273ca9ad6ebbf50a1aca42734381446a8e948e5;hb=9d044cf4ee933257c65cbd8c01589dd88778a1dd;hpb=8a0dd93c56f63de467190145116ed6c5cfd54bc1 diff --git a/src/movegen.cpp b/src/movegen.cpp index 7273ca9a..12260e3b 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -35,73 +35,79 @@ namespace { - // Function - MoveStack* generate_castle_moves(const Position&, MoveStack*); + enum CastlingSide { + KING_SIDE, + QUEEN_SIDE + }; - // Template generate_pawn_captures() with specializations - template - MoveStack* do_generate_pawn_captures(const Position& pos, MoveStack* mlist); + const bool CAPTURE = true; + const bool NON_CAPTURE = false; - template - inline MoveStack* generate_pawn_captures(const Position& p, MoveStack* m) { - return do_generate_pawn_captures(p, m); - } - template<> - inline MoveStack* generate_pawn_captures(const Position& p, MoveStack* m) { - return do_generate_pawn_captures(p, m); - } + // Functions + bool castling_is_check(const Position&, CastlingSide); - // Template generate_pawn_noncaptures() with specializations - template - MoveStack* do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist); + // Helper templates + template + MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist); - template - inline MoveStack* generate_pawn_noncaptures(const Position& p, MoveStack* m) { - return do_generate_pawn_noncaptures(p, m); - } - template<> - inline MoveStack* generate_pawn_noncaptures(const Position& p, MoveStack* m) { - return do_generate_pawn_noncaptures(p, m); - } - - // Template generate_pawn_blocking_evasions() with specializations template - MoveStack* do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist); - template - inline MoveStack* generate_pawn_blocking_evasions(const Position& p, Bitboard np, Bitboard bs, MoveStack* m) { - return do_generate_pawn_blocking_evasions(p, np, bs, m); - } - template<> - inline MoveStack* generate_pawn_blocking_evasions(const Position& p, Bitboard np, Bitboard bs, MoveStack* m) { - return do_generate_pawn_blocking_evasions(p, np, bs, m); - } + MoveStack* generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*); + + template + MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist); + + template + MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist); - // Template generate_pawn_checks() with specializations template - MoveStack* do_generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*); + MoveStack* generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*); + + // Template generate_piece_checks() with specializations + template + MoveStack* generate_piece_checks(const Position&, MoveStack*, Color, Bitboard, Square); - template - inline MoveStack* generate_pawn_checks(const Position& p, Bitboard dc, Square ksq, MoveStack* m) { - return do_generate_pawn_checks(p, dc, ksq, m); - } template<> - inline MoveStack* generate_pawn_checks(const Position& p, Bitboard dc, Square ksq, MoveStack* m) { - return do_generate_pawn_checks(p, dc, ksq, m); + inline MoveStack* generate_piece_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { + + if (us == WHITE) + return generate_pawn_checks(p, dc, ksq, m); + else + return generate_pawn_checks(p, dc, ksq, m); + } - // non-pawn templates + // Template generate_piece_moves() with specializations template MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard); + template<> MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target); - template - MoveStack* generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*); - MoveStack* generate_piece_checks_king(const Position&, Square, Bitboard, Square, MoveStack*); + template + inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us) { + + assert(Piece == PAWN); + + if (Capture) + return (us == WHITE ? generate_pawn_captures(p, m) + : generate_pawn_captures(p, m)); + else + return (us == WHITE ? generate_pawn_noncaptures(p, m) + : generate_pawn_noncaptures(p, m)); + } + // Template generate_piece_blocking_evasions() with specializations template - MoveStack* generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*); + MoveStack* generate_piece_blocking_evasions(const Position&, MoveStack*, Color us, Bitboard, Bitboard); + + template<> + inline MoveStack* generate_piece_blocking_evasions(const Position& p, MoveStack* m, Color us, + Bitboard np, Bitboard bs) { + if (us == WHITE) + return generate_pawn_blocking_evasions(p, np, bs, m); + else + return generate_pawn_blocking_evasions(p, np, bs, m); + } } @@ -126,19 +132,14 @@ int generate_captures(const Position& pos, MoveStack* mlist) { mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); - - if (us == WHITE) - mlist = generate_pawn_captures(pos, mlist); - else - mlist = generate_pawn_captures(pos, mlist); - + mlist = generate_piece_moves(pos, mlist, us); mlist = generate_piece_moves(pos, mlist, us, target); return int(mlist - mlist_start); } /// generate_noncaptures() generates all pseudo-legal non-captures and -/// underpromotions. The return value is the number of moves generated. +/// underpromotions. The return value is the number of moves generated. int generate_noncaptures(const Position& pos, MoveStack* mlist) { @@ -149,24 +150,20 @@ int generate_noncaptures(const Position& pos, MoveStack* mlist) { Bitboard target = pos.empty_squares(); MoveStack* mlist_start = mlist; - if (us == WHITE) - mlist = generate_pawn_noncaptures(pos, mlist); - else - mlist = generate_pawn_noncaptures(pos, mlist); - + mlist = generate_piece_moves(pos, mlist, us); mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_castle_moves(pos, mlist); + mlist = generate_castle_moves(pos, mlist); + mlist = generate_castle_moves(pos, mlist); return int(mlist - mlist_start); } /// generate_checks() generates all pseudo-legal non-capturing, non-promoting -/// checks, except castling moves (will add this later). It returns the -/// number of generated moves. +/// checks. It returns the number of generated moves. int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { @@ -179,35 +176,24 @@ int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { assert(pos.piece_on(ksq) == king_of_color(opposite_color(us))); - dc = pos.discovered_check_candidates(us); - - // Pawn moves - if (us == WHITE) - mlist = generate_pawn_checks(pos, dc, ksq, mlist); - else - mlist = generate_pawn_checks(pos, dc, ksq, mlist); - // Pieces moves - Bitboard b = pos.knights(us); - if (b) - mlist = generate_piece_checks(pos, b, dc, ksq, mlist); - - b = pos.bishops(us); - if (b) - mlist = generate_piece_checks(pos, b, dc, ksq, mlist); - - b = pos.rooks(us); - if (b) - mlist = generate_piece_checks(pos, b, dc, ksq, mlist); - - b = pos.queens(us); - if (b) - mlist = generate_piece_checks(pos, b, dc, ksq, mlist); - - // Hopefully we always have a king ;-) - mlist = generate_piece_checks_king(pos, pos.king_square(us), dc, ksq, mlist); - - // TODO: Castling moves! + mlist = generate_piece_checks(pos, mlist, us, dc, ksq); + mlist = generate_piece_checks(pos, mlist, us, dc, ksq); + mlist = generate_piece_checks(pos, mlist, us, dc, ksq); + mlist = generate_piece_checks(pos, mlist, us, dc, ksq); + mlist = generate_piece_checks(pos, mlist, us, dc, ksq); + mlist = generate_piece_checks(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(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(pos, mlist); return int(mlist - mlist_start); } @@ -215,7 +201,7 @@ int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { /// generate_evasions() generates all check evasions when the side to move is /// in check. Unlike the other move generation functions, this one generates -/// only legal moves. It returns the number of generated moves. This +/// only legal moves. It returns the number of generated moves. This /// function is very ugly, and needs cleaning up some time later. FIXME int generate_evasions(const Position& pos, MoveStack* mlist) { @@ -231,34 +217,51 @@ int generate_evasions(const Position& pos, MoveStack* mlist) { assert(pos.piece_on(ksq) == king_of_color(us)); - // Generate evasions for king - Bitboard b1 = pos.piece_attacks(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(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(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(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(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(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); @@ -304,29 +307,12 @@ int generate_evasions(const Position& pos, MoveStack* mlist) { assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB); - // Pawn moves. Because a blocking evasion can never be a capture, we - // only generate pawn pushes. - if (us == WHITE) - mlist = generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist); - else - mlist = generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist); - // Pieces moves - b1 = pos.knights(us) & not_pinned; - if (b1) - mlist = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist); - - b1 = pos.bishops(us) & not_pinned; - if (b1) - mlist = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist); - - b1 = pos.rooks(us) & not_pinned; - if (b1) - mlist = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist); - - b1 = pos.queens(us) & not_pinned; - if (b1) - mlist = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist); + mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); + mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); + mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); + mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); + mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); } // Finally, the ugly special case of en passant captures. An en passant @@ -366,8 +352,8 @@ int generate_evasions(const Position& pos, MoveStack* mlist) { /// generate_legal_moves() computes a complete list of legal moves in the -/// current position. This function is not very fast, and should be used -/// only in situations where performance is unimportant. It wouldn't be +/// current position. This function is not very fast, and should be used +/// only in situations where performance is unimportant. It wouldn't be /// very hard to write an efficient legal move generator, but for the moment /// we don't need it. @@ -602,8 +588,10 @@ namespace { } template - MoveStack* generate_piece_blocking_evasions(const Position& pos, Bitboard b, - Bitboard blockSquares, MoveStack* mlist) { + MoveStack* generate_piece_blocking_evasions(const Position& pos, MoveStack* mlist, Color us, + Bitboard not_pinned, Bitboard blockSquares) { + + Bitboard b = pos.pieces_of_color_and_type(us, Piece) & not_pinned; while (b) { Square from = pop_1st_bit(&b); @@ -613,11 +601,10 @@ namespace { return mlist; } - template - MoveStack* do_generate_pawn_captures(const Position& pos, MoveStack* mlist) { + MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist) { Square to; Bitboard pawns = pos.pawns(Us); @@ -690,7 +677,7 @@ namespace { template - MoveStack* do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) { + MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) { Bitboard pawns = pos.pawns(Us); Bitboard enemyPieces = pos.pieces_of_color(Them); @@ -723,10 +710,10 @@ namespace { b2 = b1 & TRank8BB; while (b2) { - to = pop_1st_bit(&b2); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); + to = pop_1st_bit(&b2); + (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK); + (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP); + (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); } b2 = b1 & ~TRank8BB; while (b2) @@ -739,44 +726,47 @@ namespace { b2 = (Us == WHITE ? (b1 & TRank3BB) << 8 : (b1 & TRank3BB) >> 8) & emptySquares; while (b2) { - to = pop_1st_bit(&b2); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + to = pop_1st_bit(&b2); + (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); } return mlist; } template - MoveStack* do_generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist) + MoveStack* 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 is not on the same file as the enemy king, because we don't - // generate captures. - Bitboard empty = pos.empty_squares(); - // Find all friendly pawns not on the enemy king's file - Bitboard b1 = pos.pawns(Us) & ~file_bb(ksq), b2, b3; + Bitboard b1, b2, b3; + Bitboard empty = pos.empty_squares(); - // Discovered checks, single pawn pushes - b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & ~TRank8BB & empty; - while (b3) + if (dc != EmptyBoardBB) { - Square to = pop_1st_bit(&b3); - (*mlist++).move = make_move(to - TDELTA_N, to); - } + // 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. + b1 = pos.pawns(Us) & ~file_bb(ksq); + + // Discovered checks, single pawn pushes, no promotions + b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & empty & ~TRank8BB; + while (b3) + { + Square to = pop_1st_bit(&b3); + (*mlist++).move = make_move(to - TDELTA_N, to); + } - // Discovered checks, double pawn pushes - b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty; - while (b3) - { - Square to = pop_1st_bit(&b3); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + // Discovered checks, double pawn pushes + b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty; + while (b3) + { + Square to = pop_1st_bit(&b3); + (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + } } // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king - - b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ?? + // of the enemy king. + b1 = pos.pawns(Us) & neighboring_files_bb(ksq) & ~dc; // Direct checks, single pawn pushes b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & empty; @@ -791,7 +781,6 @@ namespace { b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty & pos.pawn_attacks(Them, ksq); - while (b3) { Square to = pop_1st_bit(&b3); @@ -801,18 +790,28 @@ namespace { } template - MoveStack* generate_piece_checks(const Position& pos, Bitboard target, Bitboard dc, - Square ksq, MoveStack* mlist) { + MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us, + Bitboard dc, Square ksq) { + + Bitboard target = pos.pieces_of_color_and_type(us, Piece); + // Discovered checks Bitboard b = target & dc; while (b) { Square from = pop_1st_bit(&b); Bitboard bb = pos.piece_attacks(from) & pos.empty_squares(); + if (Piece == KING) + bb &= ~QueenPseudoAttacks[ksq]; + SERIALIZE_MOVES(bb); } + // Direct checks b = target & ~dc; + if (Piece == KING || !b) + return mlist; + Bitboard checkSqs = pos.piece_attacks(ksq) & pos.empty_squares(); while (b) { @@ -823,22 +822,9 @@ namespace { 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(from) - & pos.empty_squares() - & ~QueenPseudoAttacks[ksq]; - SERIALIZE_MOVES(b); - } - return mlist; - } - - template - MoveStack* do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist) { + MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, + Bitboard blockSquares, MoveStack* mlist) { Square to; // Find non-pinned pawns @@ -879,70 +865,59 @@ namespace { return mlist; } - + template MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) { Color us = pos.side_to_move(); - if (pos.can_castle(us)) + if ( (Side == KING_SIDE && pos.can_castle_kingside(us)) + ||(Side == QUEEN_SIDE && pos.can_castle_queenside(us))) { Color them = opposite_color(us); Square ksq = pos.king_square(us); assert(pos.piece_on(ksq) == king_of_color(us)); - if (pos.can_castle_kingside(us)) - { - Square rsq = pos.initial_kr_square(us); - Square g1 = relative_square(us, SQ_G1); - Square f1 = relative_square(us, SQ_F1); - Square s; - bool illegal = false; + Square rsq = (Side == KING_SIDE ? pos.initial_kr_square(us) : pos.initial_qr_square(us)); + Square s1 = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); + Square s; + bool illegal = false; - assert(pos.piece_on(rsq) == rook_of_color(us)); + assert(pos.piece_on(rsq) == rook_of_color(us)); - for (s = Min(ksq, g1); s <= Max(ksq, g1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; + // It is a bit complicated to correctly handle Chess960 + for (s = Min(ksq, s1); s <= Max(ksq, s1); s++) + if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) + || pos.square_is_attacked(s, them)) + illegal = true; - for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; + for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; - if (!illegal) - (*mlist++).move = make_castle_move(ksq, rsq); - } - - if (pos.can_castle_queenside(us)) - { - Square rsq = pos.initial_qr_square(us); - Square c1 = relative_square(us, SQ_C1); - Square d1 = relative_square(us, SQ_D1); - Square s; - bool illegal = false; - - assert(pos.piece_on(rsq) == rook_of_color(us)); - - for (s = Min(ksq, c1); s <= Max(ksq, c1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; - - for (s = Min(rsq, d1); s <= Max(rsq, d1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - - if ( square_file(rsq) == FILE_B + if ( Side == QUEEN_SIDE + && square_file(rsq) == FILE_B && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them))) illegal = true; if (!illegal) (*mlist++).move = make_castle_move(ksq, rsq); - } } 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))); + } }