X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=701a1c0f9b08615b051893f2e5d2c3ab91e199f5;hp=6de3f08c89e69b6baf72cc502343e85cfc2e363e;hb=d155cd88d1ca914c8a9d398c0164b5a92a5b9629;hpb=3b857d1625c87ae3b87ea9e960b2c8d2d3284b9a diff --git a/src/position.cpp b/src/position.cpp index 6de3f08c..701a1c0f 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -1,13 +1,14 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008 Marco Costalba - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - Glaurung is distributed in the hope that it will be useful, + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. @@ -48,13 +49,6 @@ Key Position::zobSideToMove; Value Position::MgPieceSquareTable[16][64]; Value Position::EgPieceSquareTable[16][64]; -const Piece_attacks_fn piece_attacks_fn[] = - { 0, 0, - &Position::knight_attacks, - &Position::bishop_attacks, - &Position::rook_attacks, - &Position::queen_attacks, - &Position::king_attacks }; //// //// Functions @@ -298,77 +292,70 @@ void Position::print() const { /// Position::copy() creates a copy of the input position. void Position::copy(const Position &pos) { + memcpy(this, &pos, sizeof(Position)); } /// Position:pinned_pieces() returns a bitboard of all pinned (against the /// king) pieces for the given color. - Bitboard Position::pinned_pieces(Color c) const { - Bitboard b1, b2, pinned, pinners, sliders; - Square ksq = king_square(c), s; - Color them = opposite_color(c); - - pinned = EmptyBoardBB; - b1 = occupied_squares(); - - sliders = rooks_and_queens(them) & ~checkers(); - if(sliders & RookPseudoAttacks[ksq]) { - b2 = rook_attacks(ksq) & pieces_of_color(c); - pinners = rook_attacks_bb(ksq, b1 ^ b2) & sliders; - while(pinners) { - s = pop_1st_bit(&pinners); - pinned |= (squares_between(s, ksq) & b2); - } - } - sliders = bishops_and_queens(them) & ~checkers(); - if(sliders & BishopPseudoAttacks[ksq]) { - b2 = bishop_attacks(ksq) & pieces_of_color(c); - pinners = bishop_attacks_bb(ksq, b1 ^ b2) & sliders; - while(pinners) { - s = pop_1st_bit(&pinners); - pinned |= (squares_between(s, ksq) & b2); - } - } - - return pinned; + Square ksq = king_square(c); + return hidden_checks(c, ksq) | hidden_checks(c, ksq); } + /// Position:discovered_check_candidates() returns a bitboard containing all /// pieces for the given side which are candidates for giving a discovered /// check. The code is almost the same as the function for finding pinned /// pieces. Bitboard Position::discovered_check_candidates(Color c) const { - Bitboard b1, b2, dc, checkers, sliders; - Square ksq = king_square(opposite_color(c)), s; - - dc = EmptyBoardBB; - b1 = occupied_squares(); - - sliders = rooks_and_queens(c); - if(sliders & RookPseudoAttacks[ksq]) { - b2 = rook_attacks(ksq) & pieces_of_color(c); - checkers = rook_attacks_bb(ksq, b1 ^ b2) & sliders; - while(checkers) { - s = pop_1st_bit(&checkers); - dc |= (squares_between(s, ksq) & b2); - } - } - sliders = bishops_and_queens(c); - if(sliders & BishopPseudoAttacks[ksq]) { - b2 = bishop_attacks(ksq) & pieces_of_color(c); - checkers = bishop_attacks_bb(ksq, b1 ^ b2) & sliders; - while(checkers) { - s = pop_1st_bit(&checkers); - dc |= (squares_between(s, ksq) & b2); - } - } + Square ksq = king_square(opposite_color(c)); + return hidden_checks(c, ksq) | hidden_checks(c, ksq); +} + + +/// Position:hidden_checks<>() returns a bitboard of all pinned (against the +/// king) pieces for the given color and for the given pinner type. Or, when +/// template parameter FindPinned is false, the pinned pieces of opposite color +/// that are, indeed, the pieces candidate for a discovery check. +template +Bitboard Position::hidden_checks(Color c, Square ksq) const { + + Square s; + Bitboard sliders, result = EmptyBoardBB; + + if (Piece == ROOK) // Resolved at compile time + sliders = rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]; + else + sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]; + + if (sliders && (!FindPinned || (sliders & ~checkersBB))) + { + // King blockers are candidate pinned pieces + Bitboard candidate_pinned = piece_attacks(ksq) & pieces_of_color(c); - return dc; + // Pinners are sliders, not checkers, that give check when + // candidate pinned are removed. + Bitboard pinners = (FindPinned ? sliders & ~checkersBB : sliders); + + if (Piece == ROOK) + pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); + 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) + { + s = pop_1st_bit(&pinners); + result |= (squares_between(s, ksq) & candidate_pinned); + } + } + return result; } @@ -376,12 +363,12 @@ Bitboard Position::discovered_check_candidates(Color c) const { /// given square. bool Position::square_is_attacked(Square s, Color c) const { - return - (pawn_attacks(opposite_color(c), s) & pawns(c)) || - (knight_attacks(s) & knights(c)) || - (king_attacks(s) & kings(c)) || - (rook_attacks(s) & rooks_and_queens(c)) || - (bishop_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)); } @@ -391,16 +378,17 @@ bool Position::square_is_attacked(Square s, Color c) const { /// attackers for one side. Bitboard Position::attacks_to(Square s) const { - return - (black_pawn_attacks(s) & pawns(WHITE)) | - (white_pawn_attacks(s) & pawns(BLACK)) | - (knight_attacks(s) & pieces_of_type(KNIGHT)) | - (rook_attacks(s) & rooks_and_queens()) | - (bishop_attacks(s) & bishops_and_queens()) | - (king_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); } @@ -409,20 +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 white_pawn_attacks_square(f, t); - case BP: return black_pawn_attacks_square(f, t); - case WN: case BN: return knight_attacks_square(f, t); - case WB: case BB: return bishop_attacks_square(f, t); - case WR: case BR: return rook_attacks_square(f, t); - case WQ: case BQ: return queen_attacks_square(f, t); - case WK: case BK: return king_attacks_square(f, t); - default: return false; + 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; } + 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; } @@ -434,23 +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; @@ -460,14 +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); @@ -476,33 +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; } @@ -515,138 +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 knight_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(knight_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(bishop_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(rook_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(queen_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); - } + // Discovered check? + if ( bit_is_set(dcCandidates, from) + && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) + return true; - 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); - } + // 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; } @@ -656,40 +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 white_pawn_attacks_square(t, s); - case BP: return black_pawn_attacks_square(t, s); - case WN: case BN: return knight_attacks_square(t, s); - case WB: case BB: return bishop_attacks_square(t, s); - case WR: case BR: return rook_attacks_square(t, s); - case WQ: case BQ: return queen_attacks_square(t, s); - case WK: case BK: return king_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 @@ -854,9 +836,9 @@ void Position::do_move(Move m, UndoInfo &u, Bitboard dcCandidates) { } if(piece == PAWN) { if(abs(int(to) - int(from)) == 16) { - if((us == WHITE && (white_pawn_attacks(from + DELTA_N) & + if((us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK))) || - (us == BLACK && (black_pawn_attacks(from + DELTA_S) & + (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE)))) { epSquare = Square((int(from) + int(to)) / 2); key ^= zobEp[epSquare]; @@ -889,45 +871,45 @@ void Position::do_move(Move m, UndoInfo &u, Bitboard dcCandidates) { set_bit(&checkersBB, to); if(bit_is_set(dcCandidates, from)) checkersBB |= - ((rook_attacks(ksq) & rooks_and_queens(us)) | - (bishop_attacks(ksq) & bishops_and_queens(us))); + ((piece_attacks(ksq) & rooks_and_queens(us)) | + (piece_attacks(ksq) & bishops_and_queens(us))); break; case KNIGHT: - if(bit_is_set(knight_attacks(ksq), to)) + if(bit_is_set(piece_attacks(ksq), to)) set_bit(&checkersBB, to); if(bit_is_set(dcCandidates, from)) checkersBB |= - ((rook_attacks(ksq) & rooks_and_queens(us)) | - (bishop_attacks(ksq) & bishops_and_queens(us))); + ((piece_attacks(ksq) & rooks_and_queens(us)) | + (piece_attacks(ksq) & bishops_and_queens(us))); break; case BISHOP: - if(bit_is_set(bishop_attacks(ksq), to)) + if(bit_is_set(piece_attacks(ksq), to)) set_bit(&checkersBB, to); if(bit_is_set(dcCandidates, from)) checkersBB |= - (rook_attacks(ksq) & rooks_and_queens(us)); + (piece_attacks(ksq) & rooks_and_queens(us)); break; case ROOK: - if(bit_is_set(rook_attacks(ksq), to)) + if(bit_is_set(piece_attacks(ksq), to)) set_bit(&checkersBB, to); if(bit_is_set(dcCandidates, from)) checkersBB |= - (bishop_attacks(ksq) & bishops_and_queens(us)); + (piece_attacks(ksq) & bishops_and_queens(us)); break; case QUEEN: - if(bit_is_set(queen_attacks(ksq), to)) + if(bit_is_set(piece_attacks(ksq), to)) set_bit(&checkersBB, to); break; case KING: if(bit_is_set(dcCandidates, from)) checkersBB |= - ((rook_attacks(ksq) & rooks_and_queens(us)) | - (bishop_attacks(ksq) & bishops_and_queens(us))); + ((piece_attacks(ksq) & rooks_and_queens(us)) | + (piece_attacks(ksq) & bishops_and_queens(us))); break; default: @@ -1637,10 +1619,10 @@ int Position::see(Square from, Square to) const { attackers = (rook_attacks_bb(to, occ) & rooks_and_queens()) | (bishop_attacks_bb(to, occ) & bishops_and_queens()) | - (knight_attacks(to) & knights()) | - (king_attacks(to) & kings()) | - (white_pawn_attacks(to) & pawns(BLACK)) | - (black_pawn_attacks(to) & pawns(WHITE)); + (piece_attacks(to) & knights()) | + (piece_attacks(to) & kings()) | + (pawn_attacks(WHITE, to) & pawns(BLACK)) | + (pawn_attacks(BLACK, to) & pawns(WHITE)); attackers &= occ; // If the opponent has no attackers, we are finished: @@ -2116,7 +2098,7 @@ void Position::flipped_copy(const Position &pos) { /// Position::is_ok() performs some consitency checks for the position object. /// This is meant to be helpful when debugging. -bool Position::is_ok() const { +bool Position::is_ok(int* failedStep) const { // What features of the position should be verified? static const bool debugBitboards = false; @@ -2131,23 +2113,30 @@ bool Position::is_ok() const { static const bool debugPieceCounts = false; static const bool debugPieceList = false; + if (failedStep) *failedStep = 1; + // Side to move OK? if(!color_is_ok(side_to_move())) return false; // Are the king squares in the position correct? + if (failedStep) (*failedStep)++; if(piece_on(king_square(WHITE)) != WK) return false; + + if (failedStep) (*failedStep)++; if(piece_on(king_square(BLACK)) != BK) return false; // Castle files OK? + if (failedStep) (*failedStep)++; if(!file_is_ok(initialKRFile)) return false; if(!file_is_ok(initialQRFile)) return false; // Do both sides have exactly one king? + if (failedStep) (*failedStep)++; if(debugKingCount) { int kingCount[2] = {0, 0}; for(Square s = SQ_A1; s <= SQ_H8; s++) @@ -2158,6 +2147,7 @@ bool Position::is_ok() const { } // Can the side to move capture the opponent's king? + if (failedStep) (*failedStep)++; if(debugKingCapture) { Color us = side_to_move(); Color them = opposite_color(us); @@ -2167,10 +2157,12 @@ bool Position::is_ok() const { } // Is there more than 2 checkers? + if (failedStep) (*failedStep)++; if(debugCheckerCount && count_1s(checkersBB) > 2) return false; // Bitboards OK? + if (failedStep) (*failedStep)++; if(debugBitboards) { // The intersection of the white and black pieces must be empty: if((pieces_of_color(WHITE) & pieces_of_color(BLACK)) @@ -2191,6 +2183,7 @@ bool Position::is_ok() const { } // En passant square OK? + if (failedStep) (*failedStep)++; if(ep_square() != SQ_NONE) { // The en passant square must be on rank 6, from the point of view of the // side to move. @@ -2199,18 +2192,22 @@ bool Position::is_ok() const { } // Hash key OK? + if (failedStep) (*failedStep)++; if(debugKey && key != compute_key()) return false; // Pawn hash key OK? + if (failedStep) (*failedStep)++; if(debugPawnKey && pawnKey != compute_pawn_key()) return false; // Material hash key OK? + if (failedStep) (*failedStep)++; if(debugMaterialKey && materialKey != compute_material_key()) return false; // Incremental eval OK? + if (failedStep) (*failedStep)++; if(debugIncrementalEval) { if(mgValue != compute_mg_value()) return false; @@ -2219,6 +2216,7 @@ bool Position::is_ok() const { } // Non-pawn material OK? + if (failedStep) (*failedStep)++; if(debugNonPawnMaterial) { if(npMaterial[WHITE] != compute_non_pawn_material(WHITE)) return false; @@ -2227,12 +2225,14 @@ bool Position::is_ok() const { } // Piece counts OK? + if (failedStep) (*failedStep)++; if(debugPieceCounts) for(Color c = WHITE; c <= BLACK; c++) for(PieceType pt = PAWN; pt <= KING; pt++) if(pieceCount[c][pt] != count_1s(pieces_of_color_and_type(c, pt))) return false; + if (failedStep) (*failedStep)++; if(debugPieceList) { for(Color c = WHITE; c <= BLACK; c++) for(PieceType pt = PAWN; pt <= KING; pt++) @@ -2244,6 +2244,6 @@ bool Position::is_ok() const { return false; } } - + if (failedStep) *failedStep = 0; return true; }