X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=1cb64934e95c2ace279d78a5d31f9a5e5c9a4f77;hp=982befa35dacf71960f2d1bea539c7eccd2eb297;hb=c40d4e0133d003f6caec8fd3bb0bab21f9298721;hpb=431c3ac485386cc10413fc8a3c7d338dcc71602d diff --git a/src/position.cpp b/src/position.cpp index 982befa3..1cb64934 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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 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 @@ -38,16 +38,17 @@ static const string PieceToChar(" PNBRQK pnbrqk"); CACHE_LINE_ALIGNMENT -Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; Value PieceValue[PHASE_NB][PIECE_NB] = { { VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg }, { VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } }; +static Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; + namespace Zobrist { Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; Key enpassant[FILE_NB]; - Key castling[CASTLING_FLAG_NB]; + Key castling[CASTLING_RIGHT_NB]; Key side; Key exclusion; } @@ -263,7 +264,7 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { else continue; - set_castling_flag(c, rsq); + set_castling_right(c, rsq); } // 4. En passant square. Ignore if no pawn capture is possible @@ -297,30 +298,30 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { } -/// Position::set_castling_flag() is a helper function used to set castling -/// flags given the corresponding color and the rook starting square. +/// Position::set_castling_right() is a helper function used to set castling +/// rights given the corresponding color and the rook starting square. -void Position::set_castling_flag(Color c, Square rfrom) { +void Position::set_castling_right(Color c, Square rfrom) { Square kfrom = king_square(c); CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE; - CastlingFlag cf = make_castling_flag(c, cs); + CastlingRight cr = (c | cs); - st->castlingFlags |= cf; - castlingFlagsMask[kfrom] |= cf; - castlingFlagsMask[rfrom] |= cf; - castlingRookSquare[c][cs] = rfrom; + st->castlingRights |= cr; + castlingRightsMask[kfrom] |= cr; + castlingRightsMask[rfrom] |= cr; + castlingRookSquare[cr] = rfrom; Square kto = relative_square(c, cs == KING_SIDE ? SQ_G1 : SQ_C1); Square rto = relative_square(c, cs == KING_SIDE ? SQ_F1 : SQ_D1); for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); ++s) if (s != kfrom && s != rfrom) - castlingPath[c][cs] |= s; + castlingPath[cr] |= s; for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); ++s) if (s != kfrom && s != rfrom) - castlingPath[c][cs] |= s; + castlingPath[cr] |= s; } @@ -353,21 +354,21 @@ const string Position::fen() const { ss << (sideToMove == WHITE ? " w " : " b "); if (can_castle(WHITE_OO)) - ss << (chess960 ? file_to_char(file_of(castling_rook_square(WHITE, KING_SIDE)), false) : 'K'); + ss << (chess960 ? to_char(file_of(castling_rook_square(WHITE | KING_SIDE)), false) : 'K'); if (can_castle(WHITE_OOO)) - ss << (chess960 ? file_to_char(file_of(castling_rook_square(WHITE, QUEEN_SIDE)), false) : 'Q'); + ss << (chess960 ? to_char(file_of(castling_rook_square(WHITE | QUEEN_SIDE)), false) : 'Q'); if (can_castle(BLACK_OO)) - ss << (chess960 ? file_to_char(file_of(castling_rook_square(BLACK, KING_SIDE)), true) : 'k'); + ss << (chess960 ? to_char(file_of(castling_rook_square(BLACK | KING_SIDE)), true) : 'k'); if (can_castle(BLACK_OOO)) - ss << (chess960 ? file_to_char(file_of(castling_rook_square(BLACK, QUEEN_SIDE)), true) : 'q'); + ss << (chess960 ? to_char(file_of(castling_rook_square(BLACK | QUEEN_SIDE)), true) : 'q'); if (!can_castle(WHITE) && !can_castle(BLACK)) ss << '-'; - ss << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ") + ss << (ep_square() == SQ_NONE ? " - " : " " + to_string(ep_square()) + " ") << st->rule50 << " " << 1 + (gamePly - int(sideToMove == BLACK)) / 2; return ss.str(); @@ -401,7 +402,7 @@ const string Position::pretty(Move move) const { << std::setfill('0') << std::setw(16) << st->key << "\nCheckers: "; for (Bitboard b = checkers(); b; ) - ss << square_to_string(pop_lsb(&b)) << " "; + ss << to_string(pop_lsb(&b)) << " "; ss << "\nLegal moves: "; for (MoveList it(*this); *it; ++it) @@ -411,11 +412,14 @@ const string Position::pretty(Move move) const { } -/// Position:hidden_checkers() returns a bitboard of all pinned / discovered check -/// pieces, according to the call parameters. Pinned pieces protect our king and -/// discovered check pieces attack the enemy king. +/// Position::check_blockers() returns a bitboard of all the pieces with color +/// 'c' that are blocking check on the king with color 'kingColor'. A piece +/// blocks a check if removing that piece from the board would result in a +/// position where the king is in check. A check blocking piece can be either a +/// pinned or a discovered check piece, according if its color 'c' is the same +/// or the opposite of 'kingColor'. -Bitboard Position::hidden_checkers(Color c, Color kingColor) const { +Bitboard Position::check_blockers(Color c, Color kingColor) const { Bitboard b, pinners, result = 0; Square ksq = king_square(kingColor); @@ -527,71 +531,27 @@ bool Position::pseudo_legal(const Move m) const { // Handle the special case of a pawn move if (type_of(pc) == PAWN) { - // Move direction must be compatible with pawn color - int direction = to - from; - if ((us == WHITE) != (direction > 0)) - return false; - // We have already handled promotion moves, so destination // cannot be on the 8th/1st rank. - if (rank_of(to) == RANK_8 || rank_of(to) == RANK_1) + if (rank_of(to) == relative_rank(us, RANK_8)) return false; - // Proceed according to the square delta between the origin and - // destination squares. - switch (direction) - { - case DELTA_NW: - case DELTA_NE: - case DELTA_SW: - case DELTA_SE: - // Capture. The destination square must be occupied by an enemy - // piece (en passant captures was handled earlier). - if (piece_on(to) == NO_PIECE || color_of(piece_on(to)) != ~us) - return false; - - // From and to files must be one file apart, avoids a7h5 - if (abs(file_of(from) - file_of(to)) != 1) - return false; - break; + if ( !(attacks_from(from, us) & pieces(~us) & to) // Not a capture - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!empty(to)) - return false; - break; - - case DELTA_NN: - // Double white pawn push. The destination square must be on the fourth - // rank, and both the destination square and the square between the - // source and destination squares must be empty. - if ( rank_of(to) != RANK_4 - || !empty(to) - || !empty(from + DELTA_N)) - return false; - break; - - case DELTA_SS: - // Double black pawn push. The destination square must be on the fifth - // rank, and both the destination square and the square between the - // source and destination squares must be empty. - if ( rank_of(to) != RANK_5 - || !empty(to) - || !empty(from + DELTA_S)) - return false; - break; + && !((from + pawn_push(us) == to) && empty(to)) // Not a single push - default: + && !( (from + 2 * pawn_push(us) == to) // Not a double push + && (rank_of(from) == relative_rank(us, RANK_2)) + && empty(to) + && empty(to - pawn_push(us)))) return false; - } } else if (!(attacks_from(pc, from) & to)) return false; // Evasions generator already takes care to avoid some kind of illegal moves - // and pl_move_is_legal() relies on this. We therefore have to take care that - // the same kind of moves are filtered out here. + // and legal() relies on this. We therefore have to take care that the same + // kind of moves are filtered out here. if (checkers()) { if (type_of(pc) != KING) @@ -614,7 +574,7 @@ bool Position::pseudo_legal(const Move m) const { } -/// Position::move_gives_check() tests whether a pseudo-legal move gives a check +/// Position::gives_check() tests whether a pseudo-legal move gives a check bool Position::gives_check(Move m, const CheckInfo& ci) const { @@ -633,20 +593,16 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { // Is there a discovered check? if ( unlikely(ci.dcCandidates) && (ci.dcCandidates & from) - && !aligned(from, to, king_square(~sideToMove))) + && !aligned(from, to, ci.ksq)) return true; - // Can we skip the ugly special cases? - if (type_of(m) == NORMAL) - return false; - - Color us = sideToMove; - Square ksq = king_square(~us); - switch (type_of(m)) { + case NORMAL: + return false; + case PROMOTION: - return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & ksq; + return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & ci.ksq; // En passant capture with check? We have already handled the case // of direct checks and ordinary discovered check, so the only case we @@ -657,18 +613,18 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { Square capsq = file_of(to) | rank_of(from); Bitboard b = (pieces() ^ from ^ capsq) | to; - return (attacks_bb< ROOK>(ksq, b) & pieces(us, QUEEN, ROOK)) - | (attacks_bb(ksq, b) & pieces(us, QUEEN, BISHOP)); + return (attacks_bb< ROOK>(ci.ksq, b) & pieces(sideToMove, QUEEN, ROOK)) + | (attacks_bb(ci.ksq, b) & pieces(sideToMove, QUEEN, BISHOP)); } case CASTLING: { Square kfrom = from; Square rfrom = to; // Castling is encoded as 'King captures the rook' - Square kto = relative_square(us, rfrom > kfrom ? SQ_G1 : SQ_C1); - Square rto = relative_square(us, rfrom > kfrom ? SQ_F1 : SQ_D1); + Square kto = relative_square(sideToMove, rfrom > kfrom ? SQ_G1 : SQ_C1); + Square rto = relative_square(sideToMove, rfrom > kfrom ? SQ_F1 : SQ_D1); - return (PseudoAttacks[ROOK][rto] & ksq) - && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & ksq); + return (PseudoAttacks[ROOK][rto] & ci.ksq) + && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & ci.ksq); } default: assert(false); @@ -791,12 +747,12 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->epSquare = SQ_NONE; } - // Update castling flags if needed - if (st->castlingFlags && (castlingFlagsMask[from] | castlingFlagsMask[to])) + // Update castling rights if needed + if (st->castlingRights && (castlingRightsMask[from] | castlingRightsMask[to])) { - int cf = castlingFlagsMask[from] | castlingFlagsMask[to]; - k ^= Zobrist::castling[st->castlingFlags & cf]; - st->castlingFlags &= ~cf; + int cr = castlingRightsMask[from] | castlingRightsMask[to]; + k ^= Zobrist::castling[st->castlingRights & cr]; + st->castlingRights &= ~cr; } // Prefetch TT access as soon as we know the new hash key @@ -1011,12 +967,9 @@ void Position::undo_null_move() { /// Position::see() is a static exchange evaluator: It tries to estimate the -/// material gain or loss resulting from a move. Parameter 'asymmThreshold' takes -/// tempi into account. If the side who initiated the capturing sequence does the -/// last capture, he loses a tempo and if the result is below 'asymmThreshold' -/// the capturing sequence is considered bad. +/// material gain or loss resulting from a move. -int Position::see_sign(Move m) const { +Value Position::see_sign(Move m) const { assert(is_ok(m)); @@ -1024,16 +977,17 @@ int Position::see_sign(Move m) const { // is not less then capturing one. Note that king moves always return // here because king midgame value is set to 0. if (PieceValue[MG][moved_piece(m)] <= PieceValue[MG][piece_on(to_sq(m))]) - return 1; + return VALUE_KNOWN_WIN; return see(m); } -int Position::see(Move m, int asymmThreshold) const { +Value Position::see(Move m) const { Square from, to; Bitboard occupied, attackers, stmAttackers; - int swapList[32], slIndex = 1; + Value swapList[32]; + int slIndex = 1; PieceType captured; Color stm; @@ -1049,7 +1003,7 @@ int Position::see(Move m, int asymmThreshold) const { // handled correctly. Simply return 0 that is always the correct value // unless in the rare case the rook ends up under attack. if (type_of(m) == CASTLING) - return 0; + return VALUE_ZERO; if (type_of(m) == ENPASSANT) { @@ -1080,30 +1034,24 @@ int Position::see(Move m, int asymmThreshold) const { // Add the new entry to the swap list swapList[slIndex] = -swapList[slIndex - 1] + PieceValue[MG][captured]; - ++slIndex; // Locate and remove the next least valuable attacker captured = min_attacker(byTypeBB, to, stmAttackers, occupied, attackers); - stm = ~stm; - stmAttackers = attackers & pieces(stm); // Stop before processing a king capture - if (captured == KING && stmAttackers) + if (captured == KING) { - swapList[slIndex++] = QueenValueMg * 16; + if (stmAttackers == attackers) + ++slIndex; + break; } - } while (stmAttackers); + stm = ~stm; + stmAttackers = attackers & pieces(stm); + ++slIndex; - // If we are doing asymmetric SEE evaluation and the same side does the first - // and the last capture, it loses a tempo and gain must be at least worth - // 'asymmThreshold', otherwise we replace the score with a very low value, - // before negamaxing. - if (asymmThreshold) - for (int i = 0; i < slIndex; i += 2) - if (swapList[i] < asymmThreshold) - swapList[i] = - QueenValueMg * 16; + } while (stmAttackers); // Having built the swap list, we negamax through it to find the best // achievable score from the point of view of the side to move. @@ -1136,7 +1084,7 @@ void Position::clear() { Key Position::compute_key() const { - Key k = Zobrist::castling[st->castlingFlags]; + Key k = Zobrist::castling[st->castlingRights]; for (Bitboard b = pieces(); b; ) { @@ -1185,7 +1133,7 @@ Key Position::compute_material_key() const { Key k = 0; for (Color c = WHITE; c <= BLACK; ++c) - for (PieceType pt = PAWN; pt <= QUEEN; ++pt) + for (PieceType pt = PAWN; pt <= KING; ++pt) for (int cnt = 0; cnt < pieceCount[c][pt]; ++cnt) k ^= Zobrist::psq[c][pt][cnt]; @@ -1401,14 +1349,12 @@ bool Position::pos_is_ok(int* failedStep) const { for (Color c = WHITE; c <= BLACK; ++c) for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1)) { - CastlingFlag cf = make_castling_flag(c, s); - - if (!can_castle(cf)) + if (!can_castle(c | s)) continue; - if ( (castlingFlagsMask[king_square(c)] & cf) != cf - || piece_on(castlingRookSquare[c][s]) != make_piece(c, ROOK) - || castlingFlagsMask[castlingRookSquare[c][s]] != cf) + if ( (castlingRightsMask[king_square(c)] & (c | s)) != (c | s) + || piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK) + || castlingRightsMask[castlingRookSquare[c | s]] != (c | s)) return false; }