X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=ade1c5d23327470838bb566ebb665e0a0096578b;hp=3ae7f50ddae6a99e0c5bb6dbbbefd1ea00e3d84a;hb=b638f6b0354ea124dc80e5e38189474d34141e2d;hpb=9847adf19f2017e30cd1580acaac151824e3161e diff --git a/src/position.cpp b/src/position.cpp index 3ae7f50d..ade1c5d2 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2009 Marco Costalba + Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -34,6 +34,7 @@ #include "position.h" #include "psqtab.h" #include "san.h" +#include "tt.h" #include "ucioption.h" using std::string; @@ -43,34 +44,69 @@ using std::string; //// Variables //// -int Position::castleRightsMask[64]; - Key Position::zobrist[2][8][64]; Key Position::zobEp[64]; Key Position::zobCastle[16]; Key Position::zobMaterial[2][8][16]; Key Position::zobSideToMove; +Key Position::zobExclusion; -Value Position::MgPieceSquareTable[16][64]; -Value Position::EgPieceSquareTable[16][64]; +Score Position::PieceSquareTable[16][64]; static bool RequestPending = false; -//// -//// Functions -//// /// Constructors +CheckInfo::CheckInfo(const Position& pos) { + + Color us = pos.side_to_move(); + Color them = opposite_color(us); + + ksq = pos.king_square(them); + dcCandidates = pos.discovered_check_candidates(us); + + checkSq[PAWN] = pos.attacks_from(ksq, them); + checkSq[KNIGHT] = pos.attacks_from(ksq); + checkSq[BISHOP] = pos.attacks_from(ksq); + checkSq[ROOK] = pos.attacks_from(ksq); + checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK]; + checkSq[KING] = EmptyBoardBB; +} + + +/// Position c'tors. Here we always create a slower but safer copy of +/// the original position or the FEN string, we want the new born Position +/// object do not depend on any external data. Instead if we know what we +/// are doing and we need speed we can create a position with default +/// c'tor Position() and then use just fast_copy(). + +Position::Position() {} + Position::Position(const Position& pos) { - copy(pos); + + memcpy(this, &pos, sizeof(Position)); + detach(); // Always detach() in copy c'tor to avoid surprises } Position::Position(const string& fen) { + from_fen(fen); } +/// Position::detach() copies the content of the current state and castling +/// masks inside the position itself. This is needed when the st pointee could +/// become stale, as example because the caller is about to going out of scope. + +void Position::detach() { + + startState = *st; + st = &startState; + st->previous = NULL; // as a safe guard +} + + /// Position::from_fen() initializes the position object with the given FEN /// string. This function is not very robust - make sure that input FENs are /// correct (this is assumed to be the responsibility of the GUI). @@ -129,72 +165,77 @@ void Position::from_fen(const string& fen) { } i++; - while(strchr("KQkqabcdefghABCDEFGH-", fen[i])) { - if (fen[i] == '-') - { - i++; - break; - } - else if(fen[i] == 'K') allow_oo(WHITE); - else if(fen[i] == 'Q') allow_ooo(WHITE); - else if(fen[i] == 'k') allow_oo(BLACK); - else if(fen[i] == 'q') allow_ooo(BLACK); - else if(fen[i] >= 'A' && fen[i] <= 'H') { - File rookFile, kingFile = FILE_NONE; - for(Square square = SQ_B1; square <= SQ_G1; square++) - if(piece_on(square) == WK) - kingFile = square_file(square); - if(kingFile == FILE_NONE) { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - initialKFile = kingFile; - rookFile = File(fen[i] - 'A') + FILE_A; - if(rookFile < initialKFile) { - allow_ooo(WHITE); - initialQRFile = rookFile; - } - else { - allow_oo(WHITE); - initialKRFile = rookFile; + while (strchr("KQkqabcdefghABCDEFGH-", fen[i])) { + if (fen[i] == '-') + { + i++; + break; } - } - else if(fen[i] >= 'a' && fen[i] <= 'h') { - File rookFile, kingFile = FILE_NONE; - for(Square square = SQ_B8; square <= SQ_G8; square++) - if(piece_on(square) == BK) - kingFile = square_file(square); - if(kingFile == FILE_NONE) { - std::cout << "Error in FEN at character " << i << std::endl; - return; + else if (fen[i] == 'K') allow_oo(WHITE); + else if (fen[i] == 'Q') allow_ooo(WHITE); + else if (fen[i] == 'k') allow_oo(BLACK); + else if (fen[i] == 'q') allow_ooo(BLACK); + else if (fen[i] >= 'A' && fen[i] <= 'H') { + File rookFile, kingFile = FILE_NONE; + for (Square square = SQ_B1; square <= SQ_G1; square++) + if (piece_on(square) == WK) + kingFile = square_file(square); + if (kingFile == FILE_NONE) { + std::cout << "Error in FEN at character " << i << std::endl; + return; + } + initialKFile = kingFile; + rookFile = File(fen[i] - 'A') + FILE_A; + if (rookFile < initialKFile) { + allow_ooo(WHITE); + initialQRFile = rookFile; + } + else { + allow_oo(WHITE); + initialKRFile = rookFile; + } } - initialKFile = kingFile; - rookFile = File(fen[i] - 'a') + FILE_A; - if(rookFile < initialKFile) { - allow_ooo(BLACK); - initialQRFile = rookFile; + else if (fen[i] >= 'a' && fen[i] <= 'h') { + File rookFile, kingFile = FILE_NONE; + for (Square square = SQ_B8; square <= SQ_G8; square++) + if (piece_on(square) == BK) + kingFile = square_file(square); + if (kingFile == FILE_NONE) { + std::cout << "Error in FEN at character " << i << std::endl; + return; + } + initialKFile = kingFile; + rookFile = File(fen[i] - 'a') + FILE_A; + if (rookFile < initialKFile) { + allow_ooo(BLACK); + initialQRFile = rookFile; + } + else { + allow_oo(BLACK); + initialKRFile = rookFile; + } } else { - allow_oo(BLACK); - initialKRFile = rookFile; + std::cout << "Error in FEN at character " << i << std::endl; + return; } - } - else { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - i++; + i++; } // Skip blanks while (fen[i] == ' ') i++; - // En passant square + // En passant square -- ignore if no capture is possible if ( i <= fen.length() - 2 && (fen[i] >= 'a' && fen[i] <= 'h') && (fen[i+1] == '3' || fen[i+1] == '6')) - st->epSquare = square_from_string(fen.substr(i, 2)); + { + Square fenEpSquare = square_from_string(fen.substr(i, 2)); + Color them = opposite_color(sideToMove); + if (attacks_from(fenEpSquare, them) & this->pieces(PAWN, sideToMove)) + st->epSquare = square_from_string(fen.substr(i, 2)); + } // Various initialisation for (Square sq = SQ_A1; sq <= SQ_H8; sq++) @@ -212,8 +253,7 @@ void Position::from_fen(const string& fen) { st->key = compute_key(); st->pawnKey = compute_pawn_key(); st->materialKey = compute_material_key(); - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); } @@ -253,10 +293,24 @@ const string Position::to_fen() const { fen += (sideToMove == WHITE ? "w " : "b "); if (st->castleRights != NO_CASTLES) { - if (can_castle_kingside(WHITE)) fen += 'K'; - if (can_castle_queenside(WHITE)) fen += 'Q'; - if (can_castle_kingside(BLACK)) fen += 'k'; - if (can_castle_queenside(BLACK)) fen += 'q'; + if (initialKFile == FILE_E && initialQRFile == FILE_A && initialKRFile == FILE_H) + { + if (can_castle_kingside(WHITE)) fen += 'K'; + if (can_castle_queenside(WHITE)) fen += 'Q'; + if (can_castle_kingside(BLACK)) fen += 'k'; + if (can_castle_queenside(BLACK)) fen += 'q'; + } + else + { + if (can_castle_kingside(WHITE)) + fen += char(toupper(file_to_char(initialKRFile))); + if (can_castle_queenside(WHITE)) + fen += char(toupper(file_to_char(initialQRFile))); + if (can_castle_kingside(BLACK)) + fen += file_to_char(initialKRFile); + if (can_castle_queenside(BLACK)) + fen += file_to_char(initialQRFile); + } } else fen += '-'; @@ -287,8 +341,9 @@ void Position::print(Move m) const { std::cout << std::endl; if (m != MOVE_NONE) { + Position p(*this); string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); - std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl; + std::cout << "Move is: " << col << move_to_san(p, m) << std::endl; } for (Rank rank = RANK_8; rank >= RANK_1; rank--) { @@ -313,34 +368,24 @@ void Position::print(Move m) const { } -/// Position::copy() creates a copy of the input position. - -void Position::copy(const Position& pos) { - - memcpy(this, &pos, sizeof(Position)); - saveState(); // detach and copy state info -} - - /// Position:hidden_checkers<>() 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 pieces of the given color /// candidate for a discovery check against the enemy king. -/// Note that checkersBB bitboard must be already updated. +/// Bitboard checkersBB must be already updated when looking for pinners. template Bitboard Position::hidden_checkers(Color c) const { - Bitboard pinners, result = EmptyBoardBB; + Bitboard result = EmptyBoardBB; + Bitboard pinners = pieces_of_color(FindPinned ? opposite_color(c) : c); // Pinned pieces protect our king, dicovery checks attack // the enemy king. Square ksq = king_square(FindPinned ? c : opposite_color(c)); - // Pinners are sliders, not checkers, that give check when - // candidate pinned is removed. - pinners = (rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]) - | (bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]); + // Pinners are sliders, not checkers, that give check when candidate pinned is removed + pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]); if (FindPinned && pinners) pinners &= ~st->checkersBB; @@ -361,7 +406,8 @@ Bitboard Position::hidden_checkers(Color c) const { /// Position:pinned_pieces() returns a bitboard of all pinned (against the -/// king) pieces for the given color. +/// king) pieces for the given color. Note that checkersBB bitboard must +/// be already updated. Bitboard Position::pinned_pieces(Color c) const { @@ -371,43 +417,43 @@ Bitboard Position::pinned_pieces(Color c) const { /// Position:discovered_check_candidates() returns a bitboard containing all /// pieces for the given side which are candidates for giving a discovered -/// check. +/// check. Contrary to pinned_pieces() here there is no need of checkersBB +/// to be already updated. Bitboard Position::discovered_check_candidates(Color c) const { return hidden_checkers(c); } -/// Position::attacks_to() computes a bitboard containing all pieces which +/// Position::attackers_to() computes a bitboard containing all pieces which /// attacks a given square. -Bitboard Position::attacks_to(Square s) const { +Bitboard Position::attackers_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 (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) + | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(s) & pieces(KNIGHT)) + | (attacks_from(s) & pieces(ROOK, QUEEN)) + | (attacks_from(s) & pieces(BISHOP, QUEEN)) + | (attacks_from(s) & pieces(KING)); } -/// Position::piece_attacks_square() tests whether the piece on square f -/// attacks square t. +/// Position::attacks_from() computes a bitboard of all attacks +/// of a given piece put in a given square. -bool Position::piece_attacks_square(Piece p, Square f, Square t) const { +Bitboard Position::attacks_from(Piece p, Square s) const { - assert(square_is_ok(f)); - assert(square_is_ok(t)); + assert(square_is_ok(s)); switch (p) { - 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); + case WP: return attacks_from(s, WHITE); + case BP: return attacks_from(s, BLACK); + case WN: case BN: return attacks_from(s); + case WB: case BB: return attacks_from(s); + case WR: case BR: return attacks_from(s); + case WQ: case BQ: return attacks_from(s); + case WK: case BK: return attacks_from(s); default: break; } return false; @@ -426,7 +472,7 @@ bool Position::move_attacks_square(Move m, Square s) const { assert(square_is_occupied(f)); - if (piece_attacks_square(piece_on(f), t, s)) + if (bit_is_set(attacks_from(piece_on(f), t), s)) return true; // Move the piece and scan for X-ray attacks behind it @@ -434,43 +480,35 @@ bool Position::move_attacks_square(Move m, Square s) const { Color us = color_of_piece_on(f); clear_bit(&occ, f); set_bit(&occ, t); - Bitboard xray = ( (rook_attacks_bb(s, occ) & rooks_and_queens()) - |(bishop_attacks_bb(s, occ) & bishops_and_queens())) & pieces_of_color(us); + Bitboard xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) + |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))) & pieces_of_color(us); // If we have attacks we need to verify that are caused by our move // and are not already existent ones. - return xray && (xray ^ (xray & piece_attacks(s))); + return xray && (xray ^ (xray & attacks_from(s))); } /// Position::find_checkers() computes the checkersBB bitboard, which /// contains a nonzero bit for each checking piece (0, 1 or 2). It -/// currently works by calling Position::attacks_to, which is probably +/// currently works by calling Position::attackers_to, which is probably /// inefficient. Consider rewriting this function to use the last move /// played, like in non-bitboard versions of Glaurung. void Position::find_checkers() { Color us = side_to_move(); - st->checkersBB = attacks_to(king_square(us), opposite_color(us)); + st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us)); } /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal -bool Position::pl_move_is_legal(Move m) const { - - // If we're in check, all pseudo-legal moves are legal, because our - // check evasion generator only generates true legal moves. - return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move())); -} - bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(is_ok()); assert(move_is_ok(m)); assert(pinned == pinned_pieces(side_to_move())); - assert(!is_check()); // Castling moves are checked for legality during move generation. if (move_is_castle(m)) @@ -478,12 +516,11 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Color us = side_to_move(); Square from = move_from(m); - Square ksq = king_square(us); assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == piece_of_color_and_type(us, KING)); + assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING)); - // En passant captures are a tricky special case. Because they are + // 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)) @@ -492,6 +529,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Square to = move_to(m); Square capsq = make_square(square_file(to), square_rank(from)); Bitboard b = occupied_squares(); + Square ksq = king_square(us); assert(to == ep_square()); assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); @@ -502,20 +540,46 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { 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)); + return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them)) + && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, 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), opposite_color(us))); + if (type_of_piece_on(from) == KING) + return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us))); // 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. return ( !pinned || !bit_is_set(pinned, from) - || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); + || (direction_between_squares(from, king_square(us)) == direction_between_squares(move_to(m), king_square(us)))); +} + + +/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion + +bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const +{ + assert(is_check()); + + Color us = side_to_move(); + Square from = move_from(m); + Square to = move_to(m); + + // King moves and en-passant captures are verified in pl_move_is_legal() + if (type_of_piece_on(from) == KING || move_is_ep(m)) + return pl_move_is_legal(m, pinned); + + Bitboard target = checkers(); + Square checksq = pop_1st_bit(&target); + + if (target) // double check ? + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + target = squares_between(checksq, king_square(us)) | checkers(); + return bit_is_set(target, to) && pl_move_is_legal(m, pinned); } @@ -523,161 +587,98 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { bool Position::move_is_check(Move m) const { - Bitboard dc = discovered_check_candidates(side_to_move()); - return move_is_check(m, dc); + return move_is_check(m, CheckInfo(*this)); } -bool Position::move_is_check(Move m, Bitboard dcCandidates) const { +bool Position::move_is_check(Move m, const CheckInfo& ci) const { assert(is_ok()); assert(move_is_ok(m)); - assert(dcCandidates == discovered_check_candidates(side_to_move())); + assert(ci.dcCandidates == discovered_check_candidates(side_to_move())); + assert(color_of_piece_on(move_from(m)) == side_to_move()); + assert(piece_on(ci.ksq) == piece_of_color_and_type(opposite_color(side_to_move()), KING)); - Color us = side_to_move(); - Color them = opposite_color(us); Square from = move_from(m); Square to = move_to(m); - Square ksq = king_square(them); + PieceType pt = type_of_piece_on(from); - assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == piece_of_color_and_type(them, KING)); + // Direct check ? + if (bit_is_set(ci.checkSq[pt], to)) + return true; - // Proceed according to the type of the moving piece - switch (type_of_piece_on(from)) + // Discovery check ? + if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) { - case PAWN: - - if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check? + // For pawn and king moves we need to verify also direction + if ( (pt != PAWN && pt != KING) + ||(direction_between_squares(from, ci.ksq) != direction_between_squares(to, ci.ksq))) return true; + } - if ( dcCandidates // Discovered check? - && bit_is_set(dcCandidates, from) - && (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 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)); - } + // Can we skip the ugly special cases ? + if (!move_is_special(m)) return false; - // Test discovered check and normal check according to piece type - case KNIGHT: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || bit_is_set(piece_attacks(ksq), to); - - case BISHOP: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks(ksq), to)); - - case ROOK: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_straight(ksq, to) && bit_is_set(piece_attacks(ksq), to)); - - case QUEEN: - // Discovered checks are impossible! - assert(!bit_is_set(dcCandidates, from)); - return ( (direction_is_straight(ksq, to) && bit_is_set(piece_attacks(ksq), to)) - || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks(ksq), to))); - - case KING: - // Discovered check? - if ( bit_is_set(dcCandidates, from) - && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) - return true; + Color us = side_to_move(); + Bitboard b = occupied_squares(); - // Castling with check? - if (move_is_castle(m)) - { - Square kfrom, kto, rfrom, rto; - Bitboard b = occupied_squares(); - kfrom = from; - rfrom = to; + // Promotion with check ? + if (move_is_promotion(m)) + { + clear_bit(&b, from); - 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); + switch (move_promotion_piece(m)) + { + case KNIGHT: + return bit_is_set(attacks_from(to), ci.ksq); + case BISHOP: + return bit_is_set(bishop_attacks_bb(to, b), ci.ksq); + case ROOK: + return bit_is_set(rook_attacks_bb(to, b), ci.ksq); + case QUEEN: + return bit_is_set(queen_attacks_bb(to, b), ci.ksq); + default: + assert(false); } - return false; - - default: // NO_PIECE_TYPE - break; } - assert(false); - return false; -} - - -/// Position::update_checkers() udpates chekers info given the move. It is called -/// in do_move() and is faster then find_checkers(). - -template -inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, - Square to, Bitboard dcCandidates) { - - const bool Bishop = (Piece == QUEEN || Piece == BISHOP); - const bool Rook = (Piece == QUEEN || Piece == ROOK); - const bool Slider = Bishop || Rook; - - // Direct checks - if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) - || (Rook && bit_is_set(RookPseudoAttacks[ksq], to))) - && bit_is_set(piece_attacks(ksq), to)) // slow, try to early skip - set_bit(pCheckersBB, to); - else if ( Piece != KING - && !Slider - && bit_is_set(piece_attacks(ksq), to)) - set_bit(pCheckersBB, to); + // 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. + if (move_is_ep(m)) + { + Square capsq = make_square(square_file(to), square_rank(from)); + clear_bit(&b, from); + clear_bit(&b, capsq); + set_bit(&b, to); + return (rook_attacks_bb(ci.ksq, b) & pieces(ROOK, QUEEN, us)) + ||(bishop_attacks_bb(ci.ksq, b) & pieces(BISHOP, QUEEN, us)); + } - // Discovery checks - if (Piece != QUEEN && bit_is_set(dcCandidates, from)) + // Castling with check ? + if (move_is_castle(m)) { - if (Piece != ROOK) - (*pCheckersBB) |= (piece_attacks(ksq) & rooks_and_queens(side_to_move())); + Square kfrom, kto, rfrom, rto; + kfrom = from; + rfrom = to; - if (Piece != BISHOP) - (*pCheckersBB) |= (piece_attacks(ksq) & bishops_and_queens(side_to_move())); + 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), ci.ksq); } + + return false; } @@ -687,143 +688,206 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square void Position::do_move(Move m, StateInfo& newSt) { - do_move(m, newSt, discovered_check_candidates(side_to_move())); + CheckInfo ci(*this); + do_move(m, newSt, ci, move_is_check(m, ci)); } -void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { +void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) { assert(is_ok()); assert(move_is_ok(m)); + Bitboard key = st->key; + // Copy some fields of old state to our new StateInfo object except the // ones which are recalculated from scratch anyway, then switch our state // pointer to point to the new, ready to be updated, state. struct ReducedStateInfo { - Key key, pawnKey, materialKey; - int castleRights, rule50; + Key pawnKey, materialKey; + int castleRights, rule50, pliesFromNull; Square epSquare; - Value mgValue, egValue; + Score value; Value npMaterial[2]; }; memcpy(&newSt, st, sizeof(ReducedStateInfo)); - newSt.capture = NO_PIECE_TYPE; newSt.previous = st; st = &newSt; // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = st->key; + history[gamePly] = key; + gamePly++; + + // Update side to move + key ^= zobSideToMove; // Increment the 50 moves rule draw counter. Resetting it to zero in the // case of non-reversible moves is taken care of later. st->rule50++; + st->pliesFromNull++; if (move_is_castle(m)) + { + st->key = key; do_castle_move(m); - else if (move_promotion(m)) - do_promotion_move(m); - else if (move_is_ep(m)) - do_ep_move(m); - else + return; + } + + Color us = side_to_move(); + Color them = opposite_color(us); + Square from = move_from(m); + Square to = move_to(m); + bool ep = move_is_ep(m); + bool pm = move_is_promotion(m); + + Piece piece = piece_on(from); + PieceType pt = type_of_piece(piece); + PieceType capture = ep ? PAWN : type_of_piece_on(to); + + assert(color_of_piece_on(from) == us); + assert(color_of_piece_on(to) == them || square_is_empty(to)); + assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN)); + assert(!pm || relative_rank(us, to) == RANK_8); + + if (capture) + do_capture_move(key, capture, them, to, ep); + + // Update hash key + key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; + + // Reset en passant square + if (st->epSquare != SQ_NONE) { - Color us = side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Square to = move_to(m); + key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; + } - assert(color_of_piece_on(from) == us); - assert(color_of_piece_on(to) == them || piece_on(to) == EMPTY); + // Update castle rights, try to shortcut a common case + int cm = castleRightsMask[from] & castleRightsMask[to]; + if (cm != ALL_CASTLES && ((cm & st->castleRights) != st->castleRights)) + { + key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[from]; + st->castleRights &= castleRightsMask[to]; + key ^= zobCastle[st->castleRights]; + } - PieceType piece = type_of_piece_on(from); + // Prefetch TT access as soon as we know key is updated + TT.prefetch(key); - st->capture = type_of_piece_on(to); + // Move the piece + Bitboard move_bb = make_move_bb(from, to); + do_move_bb(&(byColorBB[us]), move_bb); + do_move_bb(&(byTypeBB[pt]), move_bb); + do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares - if (st->capture) - do_capture_move(st->capture, them, to); + board[to] = board[from]; + board[from] = EMPTY; - // Move the piece - Bitboard move_bb = make_move_bb(from, to); - do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[piece]), move_bb); - do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares + // Update piece lists, note that index[from] is not updated and + // becomes stale. This works as long as index[] is accessed just + // by known occupied squares. + index[to] = index[from]; + pieceList[us][pt][index[to]] = to; - board[to] = board[from]; - board[from] = EMPTY; + // If the moving piece was a pawn do some special extra work + if (pt == PAWN) + { + // Reset rule 50 draw counter + st->rule50 = 0; - // Update hash key - st->key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to]; + // Update pawn hash key + st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - // Update incremental scores - st->mgValue -= pst(us, piece, from); - st->mgValue += pst(us, piece, to); - st->egValue -= pst(us, piece, from); - st->egValue += pst(us, piece, to); + // Set en passant square, only if moved pawn can be captured + if ((to ^ from) == 16) + { + if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) + { + st->epSquare = Square((int(from) + int(to)) / 2); + key ^= zobEp[st->epSquare]; + } + } + } - // If the moving piece was a king, update the king square - if (piece == KING) - kingSquare[us] = to; + // Update incremental scores + st->value += pst_delta(piece, from, to); - // Reset en passant square - if (st->epSquare != SQ_NONE) - { - st->key ^= zobEp[st->epSquare]; - st->epSquare = SQ_NONE; - } + // Set capture piece + st->capture = capture; - // If the moving piece was a pawn do some special extra work - if (piece == PAWN) - { - // Reset rule 50 draw counter - st->rule50 = 0; - - // Update pawn hash key - st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - - // Set en passant square, only if moved pawn can be captured - if (abs(int(to) - int(from)) == 16) - { - if ( (us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK))) - || (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE)))) - { - st->epSquare = Square((int(from) + int(to)) / 2); - st->key ^= zobEp[st->epSquare]; - } - } - } + if (pm) // promotion ? + { + PieceType promotion = move_promotion_piece(m); + + assert(promotion >= KNIGHT && promotion <= QUEEN); + + // Insert promoted piece instead of pawn + clear_bit(&(byTypeBB[PAWN]), to); + set_bit(&(byTypeBB[promotion]), to); + board[to] = piece_of_color_and_type(us, promotion); + + // Update material key + st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; + st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; + + // Update piece counts + pieceCount[us][PAWN]--; + pieceCount[us][promotion]++; + + // Update piece lists, move the last pawn at index[to] position + // and shrink the list. Add a new promotion piece to the list. + Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]]; + index[lastPawnSquare] = index[to]; + pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare; + pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; + index[to] = pieceCount[us][promotion] - 1; + pieceList[us][promotion][index[to]] = to; + + // Partially revert hash keys update + key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; + st->pawnKey ^= zobrist[us][PAWN][to]; + + // Partially revert and update incremental scores + st->value -= pst(us, PAWN, to); + st->value += pst(us, promotion, to); + + // Update material + st->npMaterial[us] += piece_value_midgame(promotion); + } - // Update piece lists - pieceList[us][piece][index[from]] = to; - index[to] = index[from]; + // Update the key with the final value + st->key = key; - // Update castle rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[from]; - st->castleRights &= castleRightsMask[to]; - st->key ^= zobCastle[st->castleRights]; + // Update checkers bitboard, piece must be already moved + st->checkersBB = EmptyBoardBB; - // Update checkers bitboard, piece must be already moved - st->checkersBB = EmptyBoardBB; - Square ksq = king_square(them); - switch (piece) - { - case PAWN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - case KNIGHT: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - case BISHOP: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - case ROOK: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - case QUEEN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - case KING: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; - default: assert(false); break; - } + if (moveIsCheck) + { + if (ep | pm) + st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); + else + { + // Direct checks + if (bit_is_set(ci.checkSq[pt], to)) + st->checkersBB = SetMaskBB[to]; + + // Discovery checks + if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) + { + if (pt != ROOK) + st->checkersBB |= (attacks_from(ci.ksq) & pieces(ROOK, QUEEN, us)); + + if (pt != BISHOP) + st->checkersBB |= (attacks_from(ci.ksq) & pieces(BISHOP, QUEEN, us)); + } + } } // Finish - st->key ^= zobSideToMove; sideToMove = opposite_color(sideToMove); - gamePly++; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -832,28 +896,40 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { /// Position::do_capture_move() is a private method used to update captured /// piece info. It is called from the main Position::do_move function. -void Position::do_capture_move(PieceType capture, Color them, Square to) { +void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Square to, bool ep) { assert(capture != KING); + Square capsq = to; + + if (ep) // en passant ? + { + capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S); + + assert(to == st->epSquare); + assert(relative_rank(opposite_color(them), to) == RANK_6); + assert(piece_on(to) == EMPTY); + assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); + + board[capsq] = EMPTY; + } + // Remove captured piece - clear_bit(&(byColorBB[them]), to); - clear_bit(&(byTypeBB[capture]), to); - clear_bit(&(byTypeBB[0]), to); + clear_bit(&(byColorBB[them]), capsq); + clear_bit(&(byTypeBB[capture]), capsq); + clear_bit(&(byTypeBB[0]), capsq); // Update hash key - st->key ^= zobrist[them][capture][to]; - - // If the captured piece was a pawn, update pawn hash key - if (capture == PAWN) - st->pawnKey ^= zobrist[them][PAWN][to]; + key ^= zobrist[them][capture][capsq]; // Update incremental scores - st->mgValue -= pst(them, capture, to); - st->egValue -= pst(them, capture, to); + st->value -= pst(them, capture, capsq); - // Update material - if (capture != PAWN) + // If the captured piece was a pawn, update pawn hash key, + // otherwise update non-pawn material. + if (capture == PAWN) + st->pawnKey ^= zobrist[them][PAWN][capsq]; + else st->npMaterial[them] -= piece_value_midgame(capture); // Update material hash key @@ -862,9 +938,17 @@ void Position::do_capture_move(PieceType capture, Color them, Square to) { // Update piece count pieceCount[them][capture]--; - // Update piece list - pieceList[them][capture][index[to]] = pieceList[them][capture][pieceCount[them][capture]]; - index[pieceList[them][capture][index[to]]] = index[to]; + // Update piece list, move the last piece at index[capsq] position + // + // WARNING: This is a not perfectly revresible operation. When we + // will reinsert the captured piece in undo_move() we will put it + // at the end of the list and not in its original place, it means + // index[] and pieceList[] are not guaranteed to be invariant to a + // do_move() + undo_move() sequence. + Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]]; + index[lastPieceSquare] = index[capsq]; + pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare; + pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; // Reset rule 50 counter st->rule50 = 0; @@ -878,13 +962,15 @@ void Position::do_capture_move(PieceType capture, Color them, Square to) { void Position::do_castle_move(Move m) { - assert(is_ok()); assert(move_is_ok(m)); assert(move_is_castle(m)); Color us = side_to_move(); Color them = opposite_color(us); + // Reset capture field + st->capture = NO_PIECE_TYPE; + // Find source squares for king and rook Square kfrom = move_from(m); Square rfrom = move_to(m); // HACK: See comment at beginning of function @@ -903,7 +989,7 @@ void Position::do_castle_move(Move m) { rto = relative_square(us, SQ_D1); } - // Remove pieces from source squares + // Remove pieces from source squares: clear_bit(&(byColorBB[us]), kfrom); clear_bit(&(byTypeBB[KING]), kfrom); clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares @@ -911,7 +997,7 @@ void Position::do_castle_move(Move m) { clear_bit(&(byTypeBB[ROOK]), rfrom); clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares - // Put pieces on destination squares + // Put pieces on destination squares: set_bit(&(byColorBB[us]), kto); set_bit(&(byTypeBB[KING]), kto); set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares @@ -920,29 +1006,22 @@ void Position::do_castle_move(Move m) { set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares // Update board array + Piece king = piece_of_color_and_type(us, KING); + Piece rook = piece_of_color_and_type(us, ROOK); board[kfrom] = board[rfrom] = EMPTY; - board[kto] = piece_of_color_and_type(us, KING); - board[rto] = piece_of_color_and_type(us, ROOK); - - // Update king square - kingSquare[us] = kto; + board[kto] = king; + board[rto] = rook; // Update piece lists pieceList[us][KING][index[kfrom]] = kto; pieceList[us][ROOK][index[rfrom]] = rto; - int tmp = index[rfrom]; + int tmp = index[rfrom]; // In Chess960 could be rto == kfrom index[kto] = index[kfrom]; index[rto] = tmp; // Update incremental scores - st->mgValue -= pst(us, KING, kfrom); - st->mgValue += pst(us, KING, kto); - st->egValue -= pst(us, KING, kfrom); - st->egValue += pst(us, KING, kto); - st->mgValue -= pst(us, ROOK, rfrom); - st->mgValue += pst(us, ROOK, rto); - st->egValue -= pst(us, ROOK, rfrom); - st->egValue += pst(us, ROOK, rto); + st->value += pst_delta(king, kfrom, kto); + st->value += pst_delta(rook, rfrom, rto); // Update hash key st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; @@ -964,243 +1043,111 @@ void Position::do_castle_move(Move m) { st->rule50 = 0; // Update checkers BB - st->checkersBB = attacks_to(king_square(them), us); -} - - -/// Position::do_promotion_move() is a private method used to make a promotion -/// move. It is called from the main Position::do_move function. - -void Position::do_promotion_move(Move m) { + st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); - Color us, them; - Square from, to; - PieceType promotion; + // Finish + sideToMove = opposite_color(sideToMove); + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); - assert(move_is_ok(m)); - assert(move_promotion(m)); - - us = side_to_move(); - them = opposite_color(us); - from = move_from(m); - to = move_to(m); - - assert(relative_rank(us, to) == RANK_8); - assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); - assert(color_of_piece_on(to) == them || square_is_empty(to)); - - st->capture = type_of_piece_on(to); - - if (st->capture) - do_capture_move(st->capture, them, to); - - // Remove pawn - clear_bit(&(byColorBB[us]), from); - clear_bit(&(byTypeBB[PAWN]), from); - clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares - board[from] = EMPTY; - - // Insert promoted piece - promotion = move_promotion(m); - assert(promotion >= KNIGHT && promotion <= QUEEN); - set_bit(&(byColorBB[us]), to); - set_bit(&(byTypeBB[promotion]), to); - set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares - board[to] = piece_of_color_and_type(us, promotion); - - // Update hash key - st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to]; - - // Update pawn hash key - st->pawnKey ^= zobrist[us][PAWN][from]; +} - // Update material key - st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; - st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; - // Update piece counts - pieceCount[us][PAWN]--; - pieceCount[us][promotion]++; +/// Position::undo_move() unmakes a move. When it returns, the position should +/// be restored to exactly the same state as before the move was made. - // Update piece lists - pieceList[us][PAWN][index[from]] = pieceList[us][PAWN][pieceCount[us][PAWN]]; - index[pieceList[us][PAWN][index[from]]] = index[from]; - pieceList[us][promotion][pieceCount[us][promotion] - 1] = to; - index[to] = pieceCount[us][promotion] - 1; +void Position::undo_move(Move m) { - // Update incremental scores - st->mgValue -= pst(us, PAWN, from); - st->mgValue += pst(us, promotion, to); - st->egValue -= pst(us, PAWN, from); - st->egValue += pst(us, promotion, to); + assert(is_ok()); + assert(move_is_ok(m)); - // Update material - st->npMaterial[us] += piece_value_midgame(promotion); + gamePly--; + sideToMove = opposite_color(sideToMove); - // Clear the en passant square - if (st->epSquare != SQ_NONE) + if (move_is_castle(m)) { - st->key ^= zobEp[st->epSquare]; - st->epSquare = SQ_NONE; + undo_castle_move(m); + return; } - // Update castle rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[to]; - st->key ^= zobCastle[st->castleRights]; - - // Reset rule 50 counter - st->rule50 = 0; - - // Update checkers BB - st->checkersBB = attacks_to(king_square(them), us); -} + Color us = side_to_move(); + Color them = opposite_color(us); + Square from = move_from(m); + Square to = move_to(m); + bool ep = move_is_ep(m); + bool pm = move_is_promotion(m); + PieceType pt = type_of_piece_on(to); -/// Position::do_ep_move() is a private method used to make an en passant -/// capture. It is called from the main Position::do_move function. + assert(square_is_empty(from)); + assert(color_of_piece_on(to) == us); + assert(!pm || relative_rank(us, to) == RANK_8); + assert(!ep || to == st->previous->epSquare); + assert(!ep || relative_rank(us, to) == RANK_6); + assert(!ep || piece_on(to) == piece_of_color_and_type(us, PAWN)); -void Position::do_ep_move(Move m) { + if (pm) // promotion ? + { + PieceType promotion = move_promotion_piece(m); + pt = PAWN; + + assert(promotion >= KNIGHT && promotion <= QUEEN); + assert(piece_on(to) == piece_of_color_and_type(us, promotion)); + + // Replace promoted piece with a pawn + clear_bit(&(byTypeBB[promotion]), to); + set_bit(&(byTypeBB[PAWN]), to); + + // Update piece counts + pieceCount[us][promotion]--; + pieceCount[us][PAWN]++; + + // Update piece list replacing promotion piece with a pawn + Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]]; + index[lastPromotionSquare] = index[to]; + pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare; + pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE; + index[to] = pieceCount[us][PAWN] - 1; + pieceList[us][PAWN][index[to]] = to; + } - Color us, them; - Square from, to, capsq; - assert(is_ok()); - assert(move_is_ok(m)); - assert(move_is_ep(m)); - - us = side_to_move(); - them = opposite_color(us); - from = move_from(m); - to = move_to(m); - capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - - assert(to == st->epSquare); - assert(relative_rank(us, to) == RANK_6); - assert(piece_on(to) == EMPTY); - assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); - assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); - - // Remove captured pawn - clear_bit(&(byColorBB[them]), capsq); - clear_bit(&(byTypeBB[PAWN]), capsq); - clear_bit(&(byTypeBB[0]), capsq); // HACK: byTypeBB[0] == occupied squares - board[capsq] = EMPTY; - - // Move capturing pawn - Bitboard move_bb = make_move_bb(from, to); + // Put the piece back at the source square + Bitboard move_bb = make_move_bb(to, from); do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[PAWN]), move_bb); + do_move_bb(&(byTypeBB[pt]), move_bb); do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares - board[to] = board[from]; - board[from] = EMPTY; - // Update material hash key - st->materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]]; - - // Update piece count - pieceCount[them][PAWN]--; + board[from] = piece_of_color_and_type(us, pt); + board[to] = EMPTY; // Update piece list - pieceList[us][PAWN][index[from]] = to; - index[to] = index[from]; - pieceList[them][PAWN][index[capsq]] = pieceList[them][PAWN][pieceCount[them][PAWN]]; - index[pieceList[them][PAWN][index[capsq]]] = index[capsq]; - - // Update hash key - st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - st->key ^= zobrist[them][PAWN][capsq]; - st->key ^= zobEp[st->epSquare]; - - // Update pawn hash key - st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - st->pawnKey ^= zobrist[them][PAWN][capsq]; - - // Update incremental scores - st->mgValue -= pst(them, PAWN, capsq); - st->mgValue -= pst(us, PAWN, from); - st->mgValue += pst(us, PAWN, to); - st->egValue -= pst(them, PAWN, capsq); - st->egValue -= pst(us, PAWN, from); - st->egValue += pst(us, PAWN, to); - - // Reset en passant square - st->epSquare = SQ_NONE; - - // Reset rule 50 counter - st->rule50 = 0; + index[from] = index[to]; + pieceList[us][pt][index[from]] = from; - // Update checkers BB - st->checkersBB = attacks_to(king_square(them), us); -} + if (st->capture) + { + Square capsq = to; + if (ep) + capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); -/// Position::undo_move() unmakes a move. When it returns, the position should -/// be restored to exactly the same state as before the move was made. + assert(st->capture != KING); + assert(!ep || square_is_empty(capsq)); -void Position::undo_move(Move m) { + // Restore the captured piece + set_bit(&(byColorBB[them]), capsq); + set_bit(&(byTypeBB[st->capture]), capsq); + set_bit(&(byTypeBB[0]), capsq); - assert(is_ok()); - assert(move_is_ok(m)); + board[capsq] = piece_of_color_and_type(them, st->capture); - gamePly--; - sideToMove = opposite_color(sideToMove); + // Update piece count + pieceCount[them][st->capture]++; - if (move_is_castle(m)) - undo_castle_move(m); - else if (move_promotion(m)) - undo_promotion_move(m); - else if (move_is_ep(m)) - undo_ep_move(m); - else - { - Color us, them; - Square from, to; - PieceType piece; - - us = side_to_move(); - them = opposite_color(us); - from = move_from(m); - to = move_to(m); - - assert(piece_on(from) == EMPTY); - assert(color_of_piece_on(to) == us); - - // Put the piece back at the source square - Bitboard move_bb = make_move_bb(to, from); - piece = type_of_piece_on(to); - do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[piece]), move_bb); - do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares - board[from] = piece_of_color_and_type(us, piece); - - // If the moving piece was a king, update the king square - if (piece == KING) - kingSquare[us] = from; - - // Update piece list - pieceList[us][piece][index[to]] = from; - index[from] = index[to]; - - if (st->capture) - { - assert(st->capture != KING); - - // Restore the captured piece - set_bit(&(byColorBB[them]), to); - set_bit(&(byTypeBB[st->capture]), to); - set_bit(&(byTypeBB[0]), to); - board[to] = piece_of_color_and_type(them, st->capture); - - // Update piece list - pieceList[them][st->capture][pieceCount[them][st->capture]] = to; - index[to] = pieceCount[them][st->capture]; - - // Update piece count - pieceCount[them][st->capture]++; - } else - board[to] = EMPTY; + // Update piece list, add a new captured piece in capsq square + index[capsq] = pieceCount[them][st->capture] - 1; + pieceList[them][st->capture][index[capsq]] = capsq; } // Finally point our state pointer back to the previous state @@ -1243,7 +1190,7 @@ void Position::undo_castle_move(Move m) { assert(piece_on(kto) == piece_of_color_and_type(us, KING)); assert(piece_on(rto) == piece_of_color_and_type(us, ROOK)); - // Remove pieces from destination squares + // Remove pieces from destination squares: clear_bit(&(byColorBB[us]), kto); clear_bit(&(byTypeBB[KING]), kto); clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares @@ -1251,7 +1198,7 @@ void Position::undo_castle_move(Move m) { clear_bit(&(byTypeBB[ROOK]), rto); clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares - // Put pieces on source squares + // Put pieces on source squares: set_bit(&(byColorBB[us]), kfrom); set_bit(&(byTypeBB[KING]), kfrom); set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares @@ -1264,133 +1211,17 @@ void Position::undo_castle_move(Move m) { board[rfrom] = piece_of_color_and_type(us, ROOK); board[kfrom] = piece_of_color_and_type(us, KING); - // Update king square - kingSquare[us] = kfrom; - // Update piece lists pieceList[us][KING][index[kto]] = kfrom; pieceList[us][ROOK][index[rto]] = rfrom; - int tmp = index[rto]; // Necessary because we may have rto == kfrom in FRC. + int tmp = index[rto]; // In Chess960 could be rto == kfrom index[kfrom] = index[kto]; index[rfrom] = tmp; -} - - -/// Position::undo_promotion_move() is a private method used to unmake a -/// promotion move. It is called from the main Position::do_move -/// function. - -void Position::undo_promotion_move(Move m) { - Color us, them; - Square from, to; - PieceType promotion; - - assert(move_is_ok(m)); - assert(move_promotion(m)); - - // When we have arrived here, some work has already been done by - // Position::undo_move. In particular, the side to move has been switched, - // so the code below is correct. - us = side_to_move(); - them = opposite_color(us); - from = move_from(m); - to = move_to(m); - - assert(relative_rank(us, to) == RANK_8); - assert(piece_on(from) == EMPTY); - - // Remove promoted piece - promotion = move_promotion(m); - assert(piece_on(to)==piece_of_color_and_type(us, promotion)); - assert(promotion >= KNIGHT && promotion <= QUEEN); - clear_bit(&(byColorBB[us]), to); - clear_bit(&(byTypeBB[promotion]), to); - clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares - - // Insert pawn at source square - set_bit(&(byColorBB[us]), from); - set_bit(&(byTypeBB[PAWN]), from); - set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares - board[from] = piece_of_color_and_type(us, PAWN); - - // Update piece list - pieceList[us][PAWN][pieceCount[us][PAWN]] = from; - index[from] = pieceCount[us][PAWN]; - pieceList[us][promotion][index[to]] = - pieceList[us][promotion][pieceCount[us][promotion] - 1]; - index[pieceList[us][promotion][index[to]]] = index[to]; - - // Update piece counts - pieceCount[us][promotion]--; - pieceCount[us][PAWN]++; - - if (st->capture) - { - assert(st->capture != KING); - - // Insert captured piece: - set_bit(&(byColorBB[them]), to); - set_bit(&(byTypeBB[st->capture]), to); - set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares - board[to] = piece_of_color_and_type(them, st->capture); - - // Update piece list - pieceList[them][st->capture][pieceCount[them][st->capture]] = to; - index[to] = pieceCount[them][st->capture]; - - // Update piece count - pieceCount[them][st->capture]++; - } else - board[to] = EMPTY; -} - - -/// Position::undo_ep_move() is a private method used to unmake an en passant -/// capture. It is called from the main Position::undo_move function. - -void Position::undo_ep_move(Move m) { - - assert(move_is_ok(m)); - assert(move_is_ep(m)); - - // When we have arrived here, some work has already been done by - // Position::undo_move. In particular, the side to move has been switched, - // so the code below is correct. - Color us = side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Square to = move_to(m); - Square capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - - assert(to == st->previous->epSquare); - assert(relative_rank(us, to) == RANK_6); - assert(piece_on(to) == piece_of_color_and_type(us, PAWN)); - assert(piece_on(from) == EMPTY); - assert(piece_on(capsq) == EMPTY); - - // Restore captured pawn - set_bit(&(byColorBB[them]), capsq); - set_bit(&(byTypeBB[PAWN]), capsq); - set_bit(&(byTypeBB[0]), capsq); - board[capsq] = piece_of_color_and_type(them, PAWN); - - // Move capturing pawn back to source square - Bitboard move_bb = make_move_bb(to, from); - do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[PAWN]), move_bb); - do_move_bb(&(byTypeBB[0]), move_bb); - board[to] = EMPTY; - board[from] = piece_of_color_and_type(us, PAWN); - - // Update piece list - pieceList[us][PAWN][index[to]] = from; - index[from] = index[to]; - pieceList[them][PAWN][pieceCount[them][PAWN]] = capsq; - index[capsq] = pieceCount[them][PAWN]; + // Finally point our state pointer back to the previous state + st = st->previous; - // Update piece count - pieceCount[them][PAWN]++; + assert(is_ok()); } @@ -1406,11 +1237,11 @@ void Position::do_null_move(StateInfo& backupSt) { // StateInfo object. // Note that differently from normal case here backupSt is actually used as // a backup storage not as a new state to be used. + backupSt.key = st->key; backupSt.epSquare = st->epSquare; - backupSt.key = st->key; - backupSt.mgValue = st->mgValue; - backupSt.egValue = st->egValue; + backupSt.value = st->value; backupSt.previous = st->previous; + backupSt.pliesFromNull = st->pliesFromNull; st->previous = &backupSt; // Save the current key to the history[] array, in order to be able to @@ -1418,19 +1249,18 @@ void Position::do_null_move(StateInfo& backupSt) { history[gamePly] = st->key; // Update the necessary information - sideToMove = opposite_color(sideToMove); if (st->epSquare != SQ_NONE) st->key ^= zobEp[st->epSquare]; + st->key ^= zobSideToMove; + TT.prefetch(st->key); + + sideToMove = opposite_color(sideToMove); st->epSquare = SQ_NONE; st->rule50++; + st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; gamePly++; - st->key ^= zobSideToMove; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; - - assert(is_ok()); } @@ -1442,18 +1272,17 @@ void Position::undo_null_move() { assert(!is_check()); // Restore information from the our backup StateInfo object - st->epSquare = st->previous->epSquare; - st->key = st->previous->key; - st->mgValue = st->previous->mgValue; - st->egValue = st->previous->egValue; - st->previous = st->previous->previous; + StateInfo* backupSt = st->previous; + st->key = backupSt->key; + st->epSquare = backupSt->epSquare; + st->value = backupSt->value; + st->previous = backupSt->previous; + st->pliesFromNull = backupSt->pliesFromNull; // Update the necessary information sideToMove = opposite_color(sideToMove); st->rule50--; gamePly--; - - assert(is_ok()); } @@ -1475,6 +1304,22 @@ int Position::see(Move m) const { return see(move_from(m), move_to(m)); } +int Position::see_sign(Move m) const { + + assert(move_is_ok(m)); + + Square from = move_from(m); + Square to = move_to(m); + + // Early return if SEE cannot be negative because capturing piece value + // is not bigger then captured one. + if ( midgame_value_of_piece_on(from) <= midgame_value_of_piece_on(to) + && type_of_piece_on(from) != KING) + return 1; + + return see(from, to); +} + int Position::see(Square from, Square to) const { // Material values @@ -1486,7 +1331,7 @@ int Position::see(Square from, Square to) const { 0, 0 }; - Bitboard attackers, stmAttackers, occ, b; + Bitboard attackers, stmAttackers, b; assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1498,10 +1343,11 @@ int Position::see(Square from, Square to) const { // Initialize pieces Piece piece = piece_on(from); Piece capture = piece_on(to); + Bitboard occ = occupied_squares(); - // Find all attackers to the destination square, with the moving piece - // removed, but possibly an X-ray attacker added behind it. - occ = occupied_squares(); + // King cannot be recaptured + if (type_of_piece(piece) == KING) + return seeValues[capture]; // Handle en passant moves if (st->epSquare == to && type_of_piece_on(from) == PAWN) @@ -1518,13 +1364,15 @@ int Position::see(Square from, Square to) const { while (true) { + // Find all attackers to the destination square, with the moving piece + // removed, but possibly an X-ray attacker added behind it. clear_bit(&occ, from); - attackers = (rook_attacks_bb(to, occ) & rooks_and_queens()) - | (bishop_attacks_bb(to, occ) & bishops_and_queens()) - | (piece_attacks(to) & knights()) - | (piece_attacks(to) & kings()) - | (pawn_attacks(WHITE, to) & pawns(BLACK)) - | (pawn_attacks(BLACK, to) & pawns(WHITE)); + attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)) + | (attacks_from(to) & pieces(KNIGHT)) + | (attacks_from(to) & pieces(KING)) + | (attacks_from(to, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(to, BLACK) & pieces(PAWN, WHITE)); if (from != SQ_NONE) break; @@ -1535,11 +1383,12 @@ int Position::see(Square from, Square to) const { // Locate the least valuable attacker to the destination square // and use it to initialize from square. + stmAttackers = attackers & pieces_of_color(us); PieceType pt; - for (pt = PAWN; !(attackers & pieces_of_color_and_type(us, pt)); pt++) + for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) assert(pt < KING); - from = first_1(attackers & pieces_of_color_and_type(us, pt)); + from = first_1(stmAttackers & pieces(pt)); piece = piece_on(from); } @@ -1567,15 +1416,15 @@ int Position::see(Square from, Square to) const { // Locate the least valuable attacker for the side to move. The loop // below looks like it is potentially infinite, but it isn't. We know // that the side to move still has at least one attacker left. - for (pt = PAWN; !(stmAttackers & pieces_of_type(pt)); pt++) + for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) assert(pt < KING); // Remove the attacker we just found from the 'attackers' bitboard, // and scan for new X-ray attacks behind the attacker. - b = stmAttackers & pieces_of_type(pt); + b = stmAttackers & pieces(pt); occ ^= (b & (~b + 1)); - attackers |= (rook_attacks_bb(to, occ) & rooks_and_queens()) - | (bishop_attacks_bb(to, occ) & bishops_and_queens()); + attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)); attackers &= occ; @@ -1608,19 +1457,6 @@ int Position::see(Square from, Square to) const { } -/// Position::saveState() copies the content of the current state -/// inside startState and makes st point to it. This is needed -/// when the st pointee could become stale, as example because -/// the caller is about to going out of scope. - -void Position::saveState() { - - startState = *st; - st = &startState; - st->previous = NULL; // as a safe guard -} - - /// Position::clear() erases the position object to a pristine state, with an /// empty board, white to move, and no castling rights. @@ -1630,19 +1466,17 @@ void Position::clear() { memset(st, 0, sizeof(StateInfo)); st->epSquare = SQ_NONE; - memset(index, 0, sizeof(int) * 64); - memset(byColorBB, 0, sizeof(Bitboard) * 2); + memset(byColorBB, 0, sizeof(Bitboard) * 2); + memset(byTypeBB, 0, sizeof(Bitboard) * 8); + memset(pieceCount, 0, sizeof(int) * 2 * 8); + memset(index, 0, sizeof(int) * 64); for (int i = 0; i < 64; i++) board[i] = EMPTY; - for (int i = 0; i < 7; i++) - { - byTypeBB[i] = EmptyBoardBB; - pieceCount[0][i] = pieceCount[1][i] = 0; - for (int j = 0; j < 8; j++) + for (int i = 0; i < 8; i++) + for (int j = 0; j < 16; j++) pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; - } sideToMove = WHITE; gamePly = 0; @@ -1681,9 +1515,6 @@ void Position::put_piece(Piece p, Square s) { set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares. pieceCount[c][pt]++; - - if (pt == KING) - kingSquare[c] = s; } @@ -1743,8 +1574,8 @@ Key Position::compute_pawn_key() const { for (Color c = WHITE; c <= BLACK; c++) { - b = pawns(c); - while(b) + b = pieces(PAWN, c); + while (b) { s = pop_1st_bit(&b); result ^= zobrist[c][PAWN][s]; @@ -1778,27 +1609,25 @@ Key Position::compute_material_key() const { /// game and the endgame. These functions are used to initialize the incremental /// scores when a new position is set up, and to verify that the scores are correctly /// updated by do_move and undo_move when the program is running in debug mode. -template -Value Position::compute_value() const { +Score Position::compute_value() const { - Value result = Value(0); + Score result = make_score(0, 0); Bitboard b; Square s; for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) { - b = pieces_of_color_and_type(c, pt); - while(b) + b = pieces(pt, c); + while (b) { s = pop_1st_bit(&b); assert(piece_on(s) == piece_of_color_and_type(c, pt)); - result += pst(c, pt, s); + result += pst(c, pt, s); } } - const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame); - result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2; + result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2); return result; } @@ -1814,7 +1643,7 @@ Value Position::compute_non_pawn_material(Color c) const { for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) { - Bitboard b = pieces_of_color_and_type(c, pt); + Bitboard b = pieces(pt, c); while (b) { assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt)); @@ -1829,11 +1658,12 @@ Value Position::compute_non_pawn_material(Color c) const { /// Position::is_draw() tests whether the position is drawn by material, /// repetition, or the 50 moves rule. It does not detect stalemates, this /// must be done by the search. +// FIXME: Currently we are not handling 50 move rule correctly when in check bool Position::is_draw() const { // Draw by material? - if ( !pawns() + if ( !pieces(PAWN) && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMidgame)) return true; @@ -1842,7 +1672,7 @@ bool Position::is_draw() const { return true; // Draw by repetition? - for (int i = 2; i < Min(gamePly, st->rule50); i += 2) + for (int i = 4; i <= Min(Min(gamePly, st->rule50), st->pliesFromNull); i += 2) if (history[gamePly - i] == st->key) return true; @@ -1856,8 +1686,7 @@ bool Position::is_draw() const { bool Position::is_mate() const { MoveStack moves[256]; - - return is_check() && !generate_evasions(*this, moves, pinned_pieces(sideToMove)); + return is_check() && (generate_moves(*this, moves, false) == moves); } @@ -1877,20 +1706,17 @@ bool Position::has_mate_threat(Color c) { do_null_move(st1); MoveStack mlist[120]; - int count; bool result = false; - Bitboard dc = discovered_check_candidates(sideToMove); Bitboard pinned = pinned_pieces(sideToMove); // Generate pseudo-legal non-capture and capture check moves - count = generate_non_capture_checks(*this, mlist, dc); - count += generate_captures(*this, mlist + count); + MoveStack* last = generate_non_capture_checks(*this, mlist); + last = generate_captures(*this, last); // Loop through the moves, and see if one of them is mate - for (int i = 0; i < count; i++) + for (MoveStack* cur = mlist; cur != last; cur++) { - Move move = mlist[i].move; - + Move move = cur->move; if (!pl_move_is_legal(move, pinned)) continue; @@ -1934,6 +1760,8 @@ void Position::init_zobrist() { for (int i = 0; i < 16; i++) zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL); + + zobExclusion = genrand_int64(); } @@ -1951,16 +1779,12 @@ void Position::init_piece_square_tables() { for (Piece p = WP; p <= WK; p++) { i = (r == 0)? 0 : (genrand_int32() % (r*2) - r); - MgPieceSquareTable[p][s] = Value(MgPST[p][s] + i); - EgPieceSquareTable[p][s] = Value(EgPST[p][s] + i); + PieceSquareTable[p][s] = make_score(MgPST[p][s] + i, EgPST[p][s] + i); } for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = BP; p <= BK; p++) - { - MgPieceSquareTable[p][s] = -MgPieceSquareTable[p-8][flip_square(s)]; - EgPieceSquareTable[p][s] = -EgPieceSquareTable[p-8][flip_square(s)]; - } + PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)]; } @@ -2015,8 +1839,7 @@ void Position::flipped_copy(const Position& pos) { st->materialKey = compute_material_key(); // Incremental scores - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); // Material st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); @@ -2043,6 +1866,7 @@ bool Position::is_ok(int* failedStep) const { static const bool debugNonPawnMaterial = false; static const bool debugPieceCounts = false; static const bool debugPieceList = false; + static const bool debugCastleSquares = false; if (failedStep) *failedStep = 1; @@ -2087,7 +1911,7 @@ bool Position::is_ok(int* failedStep) const { Color us = side_to_move(); Color them = opposite_color(us); Square ksq = king_square(them); - if (square_is_attacked(ksq, us)) + if (attackers_to(ksq) & pieces_of_color(us)) return false; } @@ -2112,7 +1936,7 @@ bool Position::is_ok(int* failedStep) const { // Separate piece type bitboards must have empty intersections for (PieceType p1 = PAWN; p1 <= KING; p1++) for (PieceType p2 = PAWN; p2 <= KING; p2++) - if (p1 != p2 && (pieces_of_type(p1) & pieces_of_type(p2))) + if (p1 != p2 && (pieces(p1) & pieces(p2))) return false; } @@ -2143,14 +1967,8 @@ bool Position::is_ok(int* failedStep) const { // Incremental eval OK? if (failedStep) (*failedStep)++; - if (debugIncrementalEval) - { - if (st->mgValue != compute_value()) - return false; - - if (st->egValue != compute_value()) - return false; - } + if (debugIncrementalEval && st->value != compute_value()) + return false; // Non-pawn material OK? if (failedStep) (*failedStep)++; @@ -2168,15 +1986,15 @@ bool Position::is_ok(int* failedStep) const { 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))) + if (pieceCount[c][pt] != count_1s(pieces(pt, c))) return false; if (failedStep) (*failedStep)++; if (debugPieceList) { - for(Color c = WHITE; c <= BLACK; c++) - for(PieceType pt = PAWN; pt <= KING; pt++) - for(int i = 0; i < pieceCount[c][pt]; i++) + for (Color c = WHITE; c <= BLACK; c++) + for (PieceType pt = PAWN; pt <= KING; pt++) + for (int i = 0; i < pieceCount[c][pt]; i++) { if (piece_on(piece_list(c, pt, i)) != piece_of_color_and_type(c, pt)) return false; @@ -2185,6 +2003,25 @@ bool Position::is_ok(int* failedStep) const { return false; } } + + if (failedStep) (*failedStep)++; + if (debugCastleSquares) { + for (Color c = WHITE; c <= BLACK; c++) { + if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != piece_of_color_and_type(c, ROOK)) + return false; + if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != piece_of_color_and_type(c, ROOK)) + return false; + } + if (castleRightsMask[initial_kr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OO)) + return false; + if (castleRightsMask[initial_qr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OOO)) + return false; + if (castleRightsMask[initial_kr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OO)) + return false; + if (castleRightsMask[initial_qr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OOO)) + return false; + } + if (failedStep) *failedStep = 0; return true; }