X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=701a1c0f9b08615b051893f2e5d2c3ab91e199f5;hp=111f5cead6808b623c6641d38c77066b86eb9869;hb=d155cd88d1ca914c8a9d398c0164b5a92a5b9629;hpb=2aebf8eb559a2a8129e6246b75f282fe5d1bc45a diff --git a/src/position.cpp b/src/position.cpp index 111f5cea..701a1c0f 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -292,6 +292,7 @@ void Position::print() const { /// Position::copy() creates a copy of the input position. void Position::copy(const Position &pos) { + memcpy(this, &pos, sizeof(Position)); } @@ -346,7 +347,6 @@ Bitboard Position::hidden_checks(Color c, Square ksq) const { else pinners &= bishop_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); - // Finally for each pinner find the corresponding pinned piece (if same color of king) // or discovery checker (if opposite color) among the candidates. while (pinners) @@ -363,12 +363,12 @@ Bitboard Position::hidden_checks(Color c, Square ksq) const { /// given square. bool Position::square_is_attacked(Square s, Color c) const { - return - (pawn_attacks(opposite_color(c), s) & pawns(c)) || - (piece_attacks(s) & knights(c)) || - (piece_attacks(s) & kings(c)) || - (piece_attacks(s) & rooks_and_queens(c)) || - (piece_attacks(s) & bishops_and_queens(c)); + + return (pawn_attacks(opposite_color(c), s) & pawns(c)) + || (piece_attacks(s) & knights(c)) + || (piece_attacks(s) & kings(c)) + || (piece_attacks(s) & rooks_and_queens(c)) + || (piece_attacks(s) & bishops_and_queens(c)); } @@ -378,16 +378,17 @@ bool Position::square_is_attacked(Square s, Color c) const { /// attackers for one side. Bitboard Position::attacks_to(Square s) const { - return - (pawn_attacks(BLACK, s) & pawns(WHITE)) | - (pawn_attacks(WHITE, s) & pawns(BLACK)) | - (piece_attacks(s) & pieces_of_type(KNIGHT)) | - (piece_attacks(s) & rooks_and_queens()) | - (piece_attacks(s) & bishops_and_queens()) | - (piece_attacks(s) & pieces_of_type(KING)); + + return (pawn_attacks(BLACK, s) & pawns(WHITE)) + | (pawn_attacks(WHITE, s) & pawns(BLACK)) + | (piece_attacks(s) & pieces_of_type(KNIGHT)) + | (piece_attacks(s) & rooks_and_queens()) + | (piece_attacks(s) & bishops_and_queens()) + | (piece_attacks(s) & pieces_of_type(KING)); } Bitboard Position::attacks_to(Square s, Color c) const { + return attacks_to(s) & pieces_of_color(c); } @@ -396,20 +397,49 @@ Bitboard Position::attacks_to(Square s, Color c) const { /// attacks square t. bool Position::piece_attacks_square(Square f, Square t) const { + assert(square_is_ok(f)); assert(square_is_ok(t)); - switch(piece_on(f)) { - case WP: return pawn_attacks_square(WHITE, f, t); - case BP: return pawn_attacks_square(BLACK, f, t); + switch (piece_on(f)) + { + case WP: return pawn_attacks_square(WHITE, f, t); + case BP: return pawn_attacks_square(BLACK, f, t); case WN: case BN: return piece_attacks_square(f, t); case WB: case BB: return piece_attacks_square(f, t); case WR: case BR: return piece_attacks_square(f, t); case WQ: case BQ: return piece_attacks_square(f, t); case WK: case BK: return piece_attacks_square(f, t); - default: return false; + default: return false; } + return false; +} + +/// Position::move_attacks_square() tests whether a move from the current +/// position attacks a given square. Only attacks by the moving piece are +/// considered; the function does not handle X-ray attacks. + +bool Position::move_attacks_square(Move m, Square s) const { + + assert(move_is_ok(m)); + assert(square_is_ok(s)); + + Square f = move_from(m), t = move_to(m); + + assert(square_is_occupied(f)); + + switch (piece_on(f)) + { + case WP: return pawn_attacks_square(WHITE, t, s); + case BP: return pawn_attacks_square(BLACK, t, s); + case WN: case BN: return piece_attacks_square(t, s); + case WB: case BB: return piece_attacks_square(t, s); + case WR: case BR: return piece_attacks_square(t, s); + case WQ: case BQ: return piece_attacks_square(t, s); + case WK: case BK: return piece_attacks_square(t, s); + default: assert(false); + } return false; } @@ -421,23 +451,24 @@ bool Position::piece_attacks_square(Square f, Square t) const { /// played, like in non-bitboard versions of Glaurung. void Position::find_checkers() { - checkersBB = attacks_to(king_square(side_to_move()), - opposite_color(side_to_move())); + + checkersBB = attacks_to(king_square(side_to_move()),opposite_color(side_to_move())); } /// Position::move_is_legal() tests whether a pseudo-legal move is legal. /// There are two versions of this function: One which takes only a /// move as input, and one which takes a move and a bitboard of pinned -/// pieces. The latter function is faster, and should always be preferred +/// pieces. The latter function is faster, and should always be preferred /// when a pinned piece bitboard has already been computed. bool Position::move_is_legal(Move m) const { + return move_is_legal(m, pinned_pieces(side_to_move())); } - bool Position::move_is_legal(Move m, Bitboard pinned) const { + Color us, them; Square ksq, from; @@ -447,14 +478,15 @@ bool Position::move_is_legal(Move m, Bitboard pinned) const { // If we're in check, all pseudo-legal moves are legal, because our // check evasion generator only generates true legal moves. - if(is_check()) return true; + if (is_check()) + return true; // Castling moves are checked for legality during move generation. - if(move_is_castle(m)) return true; + if (move_is_castle(m)) + return true; us = side_to_move(); them = opposite_color(us); - from = move_from(m); ksq = king_square(us); @@ -463,33 +495,36 @@ bool Position::move_is_legal(Move m, Bitboard pinned) const { // En passant captures are a tricky special case. Because they are // rather uncommon, we do it simply by testing whether the king is attacked - // after the move is made: - if(move_is_ep(m)) { - Square to = move_to(m); - Square capsq = make_square(square_file(to), square_rank(from)); - Bitboard b = occupied_squares(); - - assert(to == ep_square()); - assert(piece_on(from) == pawn_of_color(us)); - assert(piece_on(capsq) == pawn_of_color(them)); - assert(piece_on(to) == EMPTY); - - clear_bit(&b, from); clear_bit(&b, capsq); set_bit(&b, to); - return - (!(rook_attacks_bb(ksq, b) & rooks_and_queens(them)) && - !(bishop_attacks_bb(ksq, b) & bishops_and_queens(them))); + // after the move is made + if (move_is_ep(m)) + { + Square to = move_to(m); + Square capsq = make_square(square_file(to), square_rank(from)); + Bitboard b = occupied_squares(); + + assert(to == ep_square()); + assert(piece_on(from) == pawn_of_color(us)); + assert(piece_on(capsq) == pawn_of_color(them)); + assert(piece_on(to) == EMPTY); + + clear_bit(&b, from); + clear_bit(&b, capsq); + set_bit(&b, to); + + return !(rook_attacks_bb(ksq, b) & rooks_and_queens(them)) + && !(bishop_attacks_bb(ksq, b) & bishops_and_queens(them)); } // If the moving piece is a king, check whether the destination // square is attacked by the opponent. - if(from == ksq) return !(square_is_attacked(move_to(m), them)); + if (from == ksq) + return !(square_is_attacked(move_to(m), them)); // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. - if(!bit_is_set(pinned, from)) return true; - if(direction_between_squares(from, ksq) == - direction_between_squares(move_to(m), ksq)) - return true; + if ( !bit_is_set(pinned, from) + || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))) + return true; return false; } @@ -502,138 +537,126 @@ bool Position::move_is_legal(Move m, Bitboard pinned) const { /// when a discovered check candidates bitboard has already been computed. bool Position::move_is_check(Move m) const { + Bitboard dc = discovered_check_candidates(side_to_move()); return move_is_check(m, dc); } - bool Position::move_is_check(Move m, Bitboard dcCandidates) const { + Color us, them; Square ksq, from, to; assert(is_ok()); assert(move_is_ok(m)); - assert(dcCandidates == - discovered_check_candidates(side_to_move())); + assert(dcCandidates == discovered_check_candidates(side_to_move())); us = side_to_move(); them = opposite_color(us); - from = move_from(m); to = move_to(m); ksq = king_square(them); + assert(color_of_piece_on(from) == us); assert(piece_on(ksq) == king_of_color(them)); - // Proceed according to the type of the moving piece: - switch(type_of_piece_on(from)) { + // Proceed according to the type of the moving piece + switch (type_of_piece_on(from)) + { case PAWN: - // Normal check? - if(bit_is_set(pawn_attacks(them, ksq), to)) - return true; - // Discovered check? - else if(bit_is_set(dcCandidates, from) && - direction_between_squares(from, ksq) != - direction_between_squares(to, ksq)) - return true; - // Promotion with check? - else if(move_promotion(m)) { - Bitboard b = occupied_squares(); - clear_bit(&b, from); + + if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check? + return true; + + if ( bit_is_set(dcCandidates, from) // Discovered check? + && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) + return true; + + if (move_promotion(m)) // Promotion with check? + { + Bitboard b = occupied_squares(); + clear_bit(&b, from); - switch(move_promotion(m)) { - case KNIGHT: - return piece_attacks_square(to, ksq); - case BISHOP: - return bit_is_set(bishop_attacks_bb(to, b), ksq); - case ROOK: - return bit_is_set(rook_attacks_bb(to, b), ksq); - case QUEEN: - return bit_is_set(queen_attacks_bb(to, b), ksq); - default: - assert(false); + switch (move_promotion(m)) + { + case KNIGHT: + return bit_is_set(piece_attacks(to), ksq); + case BISHOP: + return bit_is_set(bishop_attacks_bb(to, b), ksq); + case ROOK: + return bit_is_set(rook_attacks_bb(to, b), ksq); + case QUEEN: + return bit_is_set(queen_attacks_bb(to, b), ksq); + default: + assert(false); + } } - } - // En passant capture with check? We have already handled the case - // of direct checks and ordinary discovered check, the only case we - // need to handle is the unusual case of a discovered check through the - // captured pawn. - else if(move_is_ep(m)) { - Square capsq = make_square(square_file(to), square_rank(from)); - Bitboard b = occupied_squares(); - - clear_bit(&b, from); clear_bit(&b, capsq); set_bit(&b, to); - return - ((rook_attacks_bb(ksq, b) & rooks_and_queens(us)) || - (bishop_attacks_bb(ksq, b) & bishops_and_queens(us))); - } - return false; + // En passant capture with check? We have already handled the case + // of direct checks and ordinary discovered check, the only case we + // need to handle is the unusual case of a discovered check through the + // captured pawn. + else if (move_is_ep(m)) + { + Square capsq = make_square(square_file(to), square_rank(from)); + Bitboard b = occupied_squares(); + clear_bit(&b, from); + clear_bit(&b, capsq); + set_bit(&b, to); + return (rook_attacks_bb(ksq, b) & rooks_and_queens(us)) + ||(bishop_attacks_bb(ksq, b) & bishops_and_queens(us)); + } + return false; - case KNIGHT: - // Discovered check? - if(bit_is_set(dcCandidates, from)) - return true; - // Normal check? - else - return bit_is_set(piece_attacks(ksq), to); + case KNIGHT: + return bit_is_set(dcCandidates, from) // Discovered check? + || bit_is_set(piece_attacks(ksq), to); // Normal check? case BISHOP: - // Discovered check? - if(bit_is_set(dcCandidates, from)) - return true; - // Normal check? - else - return bit_is_set(piece_attacks(ksq), to); + return bit_is_set(dcCandidates, from) // Discovered check? + || bit_is_set(piece_attacks(ksq), to); // Normal check? case ROOK: - // Discovered check? - if(bit_is_set(dcCandidates, from)) - return true; - // Normal check? - else - return bit_is_set(piece_attacks(ksq), to); + return bit_is_set(dcCandidates, from) // Discovered check? + || bit_is_set(piece_attacks(ksq), to); // Normal check? case QUEEN: - // Discovered checks are impossible! - assert(!bit_is_set(dcCandidates, from)); - // Normal check? - return bit_is_set(piece_attacks(ksq), to); + // Discovered checks are impossible! + assert(!bit_is_set(dcCandidates, from)); + return bit_is_set(piece_attacks(ksq), to); // Normal check? case KING: - // Discovered check? - if(bit_is_set(dcCandidates, from) && - direction_between_squares(from, ksq) != - direction_between_squares(to, ksq)) - return true; - // Castling with check? - if(move_is_castle(m)) { - Square kfrom, kto, rfrom, rto; - Bitboard b = occupied_squares(); - - kfrom = from; - rfrom = to; - if(rfrom > kfrom) { - kto = relative_square(us, SQ_G1); - rto = relative_square(us, SQ_F1); - } - else { - kto = relative_square(us, SQ_C1); - rto = relative_square(us, SQ_D1); - } - - clear_bit(&b, kfrom); clear_bit(&b, rfrom); - set_bit(&b, rto); set_bit(&b, kto); + // Discovered check? + if ( bit_is_set(dcCandidates, from) + && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) + return true; - return bit_is_set(rook_attacks_bb(rto, b), ksq); - } + // Castling with check? + if (move_is_castle(m)) + { + Square kfrom, kto, rfrom, rto; + Bitboard b = occupied_squares(); + kfrom = from; + rfrom = to; - return false; + if (rfrom > kfrom) + { + kto = relative_square(us, SQ_G1); + rto = relative_square(us, SQ_F1); + } else { + kto = relative_square(us, SQ_C1); + rto = relative_square(us, SQ_D1); + } + clear_bit(&b, kfrom); + clear_bit(&b, rfrom); + set_bit(&b, rto); + set_bit(&b, kto); + return bit_is_set(rook_attacks_bb(rto, b), ksq); + } + return false; default: - assert(false); - return false; + assert(false); } - assert(false); return false; } @@ -643,40 +666,12 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { /// position is a capture. bool Position::move_is_capture(Move m) const { - return - color_of_piece_on(move_to(m)) == opposite_color(side_to_move()) - || move_is_ep(m); -} - - -/// Position::move_attacks_square() tests whether a move from the current -/// position attacks a given square. Only attacks by the moving piece are -/// considered; the function does not handle X-ray attacks. - -bool Position::move_attacks_square(Move m, Square s) const { - assert(move_is_ok(m)); - assert(square_is_ok(s)); - Square f = move_from(m), t = move_to(m); - - assert(square_is_occupied(f)); - - switch(piece_on(f)) { - case WP: return pawn_attacks_square(WHITE, t, s); - case BP: return pawn_attacks_square(BLACK, t, s); - case WN: case BN: return piece_attacks_square(t, s); - case WB: case BB: return piece_attacks_square(t, s); - case WR: case BR: return piece_attacks_square(t, s); - case WQ: case BQ: return piece_attacks_square(t, s); - case WK: case BK: return piece_attacks_square(t, s); - default: assert(false); - } - - return false; + return color_of_piece_on(move_to(m)) == opposite_color(side_to_move()) + || move_is_ep(m); } - /// Position::backup() is called when making a move. All information /// necessary to restore the position when the move is later unmade /// is saved to an UndoInfo object. The function Position::restore