X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=c17c5c5757e550680ee9929e144dcbf5bf3f2216;hp=21839d6abaf32e52e48d027e4a9b626864496fc3;hb=190f88e5324ffd048c5234e78b41748432dc7579;hpb=68e711aac603388d38490521cf336b535aa10c91 diff --git a/src/position.cpp b/src/position.cpp index 21839d6a..c17c5c57 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 Marco Costalba + Copyright (C) 2008-2009 Marco Costalba Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -27,6 +27,7 @@ #include #include +#include "bitcount.h" #include "mersenne.h" #include "movegen.h" #include "movepick.h" @@ -35,13 +36,13 @@ #include "san.h" #include "ucioption.h" +using std::string; + //// //// Variables //// -extern SearchStack EmptySearchStack; - int Position::castleRightsMask[64]; Key Position::zobrist[2][8][64]; @@ -65,7 +66,7 @@ Position::Position(const Position& pos) { copy(pos); } -Position::Position(const std::string& fen) { +Position::Position(const string& fen) { from_fen(fen); } @@ -74,9 +75,9 @@ Position::Position(const std::string& 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). -void Position::from_fen(const std::string& fen) { +void Position::from_fen(const string& fen) { - static const std::string pieceLetters = "KQRBNPkqrbnp"; + static const string pieceLetters = "KQRBNPkqrbnp"; static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP }; clear(); @@ -100,7 +101,7 @@ void Position::from_fen(const std::string& fen) { continue; } size_t idx = pieceLetters.find(fen[i]); - if (idx == std::string::npos) + if (idx == string::npos) { std::cout << "Error in FEN at character " << i << std::endl; return; @@ -190,7 +191,7 @@ void Position::from_fen(const std::string& fen) { i++; // En passant square - if ( i < fen.length() - 2 + 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)); @@ -213,18 +214,18 @@ void Position::from_fen(const std::string& fen) { st->materialKey = compute_material_key(); st->mgValue = compute_value(); st->egValue = compute_value(); - npMaterial[WHITE] = compute_non_pawn_material(WHITE); - npMaterial[BLACK] = compute_non_pawn_material(BLACK); + st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); + st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); } /// Position::to_fen() converts the position object to a FEN string. This is /// probably only useful for debugging. -const std::string Position::to_fen() const { +const string Position::to_fen() const { - static const std::string pieceLetters = " PNBRQK pnbrqk"; - std::string fen; + static const string pieceLetters = " PNBRQK pnbrqk"; + string fen; int skip; for (Rank rank = RANK_8; rank >= RANK_1; rank--) @@ -274,7 +275,7 @@ const std::string Position::to_fen() const { void Position::print(Move m) const { - static const std::string pieceLetters = " PNBRQK PNBRQK ."; + static const string pieceLetters = " PNBRQK PNBRQK ."; // Check for reentrancy, as example when called from inside // MovePicker that is used also here in move_to_san() @@ -286,7 +287,7 @@ void Position::print(Move m) const { std::cout << std::endl; if (m != MOVE_NONE) { - std::string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); + string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl; } for (Rank rank = RANK_8; rank >= RANK_1; rank--) @@ -314,9 +315,10 @@ void Position::print(Move m) const { /// Position::copy() creates a copy of the input position. -void Position::copy(const Position &pos) { +void Position::copy(const Position& pos) { memcpy(this, &pos, sizeof(Position)); + saveState(); // detach and copy state info } @@ -358,10 +360,26 @@ Bitboard Position::hidden_checkers(Color c) const { } +/// Position:pinned_pieces() returns a bitboard of all pinned (against the +/// king) pieces for the given color. + +Bitboard Position::pinned_pieces(Color c) const { + + return hidden_checkers(c); +} + + +/// Position:discovered_check_candidates() returns a bitboard containing all +/// pieces for the given side which are candidates for giving a discovered +/// check. + +Bitboard Position::discovered_check_candidates(Color c) const { + + return hidden_checkers(c); +} + /// Position::attacks_to() computes a bitboard containing all pieces which -/// attacks a given square. There are two versions of this function: One -/// which finds attackers of both colors, and one which only finds the -/// attackers for one side. +/// attacks a given square. Bitboard Position::attacks_to(Square s) const { @@ -442,7 +460,9 @@ void Position::find_checkers() { bool Position::pl_move_is_legal(Move m) const { - return pl_move_is_legal(m, pinned_pieces(side_to_move())); + // 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 { @@ -450,18 +470,13 @@ 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())); - - // 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; + assert(!is_check()); // Castling moves are checked for legality during move generation. if (move_is_castle(m)) return true; Color us = side_to_move(); - Color them = opposite_color(us); Square from = move_from(m); Square ksq = king_square(us); @@ -473,6 +488,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // after the move is made if (move_is_ep(m)) { + Color them = opposite_color(us); Square to = move_to(m); Square capsq = make_square(square_file(to), square_rank(from)); Bitboard b = occupied_squares(); @@ -493,11 +509,12 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // 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)); + return !(square_is_attacked(move_to(m), 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 ( !bit_is_set(pinned, from) + return ( !pinned + || !bit_is_set(pinned, from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } @@ -533,7 +550,8 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check? return true; - if ( bit_is_set(dcCandidates, from) // Discovered check? + if ( dcCandidates // Discovered check? + && bit_is_set(dcCandidates, from) && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) return true; @@ -572,22 +590,24 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { } return false; + // Test discovered check and normal check according to piece type case KNIGHT: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + return (dcCandidates && bit_is_set(dcCandidates, from)) + || bit_is_set(piece_attacks(ksq), to); case BISHOP: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + return (dcCandidates && bit_is_set(dcCandidates, from)) + || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks(ksq), to)); case ROOK: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + 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 bit_is_set(piece_attacks(ksq), to); // Normal check? + 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? @@ -627,20 +647,6 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { } -/// Position::move_is_capture() tests whether a move from the current -/// position is a capture. Move must not be MOVE_NONE. - -bool Position::move_is_capture(Move m) const { - - assert(m != MOVE_NONE); - - return ( !square_is_empty(move_to(m)) - && (color_of_piece_on(move_to(m)) != color_of_piece_on(move_from(m))) - ) - || move_is_ep(m); -} - - /// Position::update_checkers() udpates chekers info given the move. It is called /// in do_move() and is faster then find_checkers(). @@ -648,9 +654,22 @@ template inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates) { - if (Piece != KING && bit_is_set(piece_attacks(ksq), to)) + 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); + + // Discovery checks if (Piece != QUEEN && bit_is_set(dcCandidates, from)) { if (Piece != ROOK) @@ -684,6 +703,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { int castleRights, rule50; Square epSquare; Value mgValue, egValue; + Value npMaterial[2]; }; memcpy(&newSt, st, sizeof(ReducedStateInfo)); @@ -720,15 +740,14 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->capture = type_of_piece_on(to); if (st->capture) - do_capture_move(m, st->capture, them, to); + do_capture_move(st->capture, them, to); // Move the piece - clear_bit(&(byColorBB[us]), from); - clear_bit(&(byTypeBB[piece]), from); - clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares - set_bit(&(byColorBB[us]), to); - set_bit(&(byTypeBB[piece]), to); - set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares + 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 + board[to] = board[from]; board[from] = EMPTY; @@ -777,11 +796,14 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { pieceList[us][piece][index[from]] = to; index[to] = index[from]; - // Update castle rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[from]; - st->castleRights &= castleRightsMask[to]; - st->key ^= zobCastle[st->castleRights]; + // Update castle rights, try to shortcut a common case + if ((castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES) + { + 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; @@ -813,13 +835,14 @@ 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(Move m, PieceType capture, Color them, Square to) { +void Position::do_capture_move(PieceType capture, Color them, Square to) { assert(capture != KING); // Remove captured piece clear_bit(&(byColorBB[them]), to); clear_bit(&(byTypeBB[capture]), to); + clear_bit(&(byTypeBB[0]), to); // Update hash key st->key ^= zobrist[them][capture][to]; @@ -832,11 +855,9 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to) st->mgValue -= pst(them, capture, to); st->egValue -= pst(them, capture, to); - assert(!move_promotion(m) || capture != PAWN); - // Update material if (capture != PAWN) - npMaterial[them] -= piece_value_midgame(capture); + st->npMaterial[them] -= piece_value_midgame(capture); // Update material hash key st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]]; @@ -975,7 +996,7 @@ void Position::do_promotion_move(Move m) { st->capture = type_of_piece_on(to); if (st->capture) - do_capture_move(m, st->capture, them, to); + do_capture_move(st->capture, them, to); // Remove pawn clear_bit(&(byColorBB[us]), from); @@ -1018,7 +1039,7 @@ void Position::do_promotion_move(Move m) { st->egValue += pst(us, promotion, to); // Update material - npMaterial[us] += piece_value_midgame(promotion); + st->npMaterial[us] += piece_value_midgame(promotion); // Clear the en passant square if (st->epSquare != SQ_NONE) @@ -1064,21 +1085,17 @@ void Position::do_ep_move(Move m) { assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); - // Remove captured piece + // 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; - // Remove moving piece from source square - clear_bit(&(byColorBB[us]), from); - clear_bit(&(byTypeBB[PAWN]), from); - clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares - - // Put moving piece on destination square - set_bit(&(byColorBB[us]), to); - set_bit(&(byTypeBB[PAWN]), to); - set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares + // Move capturing pawn + Bitboard move_bb = make_move_bb(from, to); + do_move_bb(&(byColorBB[us]), move_bb); + do_move_bb(&(byTypeBB[PAWN]), move_bb); + do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares board[to] = board[from]; board[from] = EMPTY; @@ -1154,17 +1171,13 @@ void Position::undo_move(Move m) { 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); - set_bit(&(byColorBB[us]), from); - set_bit(&(byTypeBB[piece]), from); - set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares + 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); - // Clear the destination square - clear_bit(&(byColorBB[us]), to); - clear_bit(&(byTypeBB[piece]), to); - clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares - // If the moving piece was a king, update the king square if (piece == KING) kingSquare[us] = from; @@ -1177,16 +1190,12 @@ void Position::undo_move(Move m) { { assert(st->capture != KING); - // Replace the captured piece + // 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 material - if (st->capture != PAWN) - npMaterial[them] += piece_value_midgame(st->capture); - // Update piece list pieceList[them][st->capture][pieceCount[them][st->capture]] = to; index[to] = pieceCount[them][st->capture]; @@ -1197,7 +1206,7 @@ void Position::undo_move(Move m) { board[to] = EMPTY; } - // Finally point out state pointer back to the previous state + // Finally point our state pointer back to the previous state st = st->previous; assert(is_ok()); @@ -1308,9 +1317,6 @@ void Position::undo_promotion_move(Move m) { set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares board[from] = piece_of_color_and_type(us, PAWN); - // Update material - npMaterial[us] -= piece_value_midgame(promotion); - // Update piece list pieceList[us][PAWN][pieceCount[us][PAWN]] = from; index[from] = pieceCount[us][PAWN]; @@ -1332,11 +1338,6 @@ void Position::undo_promotion_move(Move m) { set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares board[to] = piece_of_color_and_type(them, st->capture); - // Update material. Because the move is a promotion move, we know - // that the captured piece cannot be a pawn. - assert(st->capture != PAWN); - npMaterial[them] += piece_value_midgame(st->capture); - // Update piece list pieceList[them][st->capture][pieceCount[them][st->capture]] = to; index[to] = pieceCount[them][st->capture]; @@ -1371,31 +1372,27 @@ void Position::undo_ep_move(Move m) { assert(piece_on(from) == EMPTY); assert(piece_on(capsq) == EMPTY); - // Replace captured piece + // 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); - // Remove moving piece from destination square - clear_bit(&(byColorBB[us]), to); - clear_bit(&(byTypeBB[PAWN]), to); - clear_bit(&(byTypeBB[0]), to); + // 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; - - // Replace moving piece at source square - set_bit(&(byColorBB[us]), from); - set_bit(&(byTypeBB[PAWN]), from); - set_bit(&(byTypeBB[0]), from); board[from] = piece_of_color_and_type(us, PAWN); - // Update piece list: + // 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]; - // Update piece count: + // Update piece count pieceCount[them][PAWN]++; } @@ -1403,18 +1400,21 @@ void Position::undo_ep_move(Move m) { /// Position::do_null_move makes() a "null move": It switches the side to move /// and updates the hash key without executing any move on the board. -void Position::do_null_move(StateInfo& newSt) { +void Position::do_null_move(StateInfo& backupSt) { assert(is_ok()); assert(!is_check()); // Back up the information necessary to undo the null move to the supplied - // StateInfo object. In the case of a null move, the only thing we need to - // remember is the last move made and the en passant square. - newSt.lastMove = st->lastMove; - newSt.epSquare = st->epSquare; - newSt.previous = st->previous; - st->previous = &newSt; + // 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.epSquare = st->epSquare; + backupSt.key = st->key; + backupSt.mgValue = st->mgValue; + backupSt.egValue = st->egValue; + backupSt.previous = st->previous; + st->previous = &backupSt; // Save the current key to the history[] array, in order to be able to // detect repetition draws. @@ -1444,22 +1444,17 @@ void Position::undo_null_move() { assert(is_ok()); assert(!is_check()); - // Restore information from the our StateInfo object - st->lastMove = st->previous->lastMove; + // 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; - if (st->epSquare != SQ_NONE) - st->key ^= zobEp[st->epSquare]; - // Update the necessary information sideToMove = opposite_color(sideToMove); st->rule50--; gamePly--; - st->key ^= zobSideToMove; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; assert(is_ok()); } @@ -1494,7 +1489,7 @@ int Position::see(Square from, Square to) const { 0, 0 }; - Bitboard attackers, occ, b; + Bitboard attackers, stmAttackers, occ, b; assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1518,7 +1513,6 @@ int Position::see(Square from, Square to) const { Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S); capture = piece_on(capQq); - assert(type_of_piece_on(capQq) == PAWN); // Remove the captured pawn @@ -1553,7 +1547,8 @@ int Position::see(Square from, Square to) const { } // If the opponent has no attackers we are finished - if ((attackers & pieces_of_color(them)) == EmptyBoardBB) + stmAttackers = attackers & pieces_of_color(them); + if (!stmAttackers) return seeValues[capture]; attackers &= occ; // Remove the moving piece @@ -1575,13 +1570,13 @@ 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; !(attackers & pieces_of_color_and_type(c, pt)); pt++) + for (pt = PAWN; !(stmAttackers & pieces_of_type(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 = attackers & pieces_of_color_and_type(c, pt); - occ ^= (b & -b); + b = stmAttackers & pieces_of_type(pt); + occ ^= (b & (~b + 1)); attackers |= (rook_attacks_bb(to, occ) & rooks_and_queens()) | (bishop_attacks_bb(to, occ) & bishops_and_queens()); @@ -1596,15 +1591,16 @@ int Position::see(Square from, Square to) const { // before beginning the next iteration lastCapturingPieceValue = seeValues[pt]; c = opposite_color(c); + stmAttackers = attackers & pieces_of_color(c); // Stop after a king capture - if (pt == KING && (attackers & pieces_of_color(c))) + if (pt == KING && stmAttackers) { assert(n < 32); - swapList[n++] = 100; + swapList[n++] = QueenValueMidgame*10; break; } - } while (attackers & pieces_of_color(c)); + } 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 @@ -1615,15 +1611,16 @@ int Position::see(Square from, Square to) const { } -/// Position::setStartState() copies the content of the argument +/// 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::setStartState(const StateInfo& s) { +void Position::saveState() { - startState = s; + startState = *st; st = &startState; + st->previous = NULL; // as a safe guard } @@ -1817,15 +1814,14 @@ Value Position::compute_value() const { Value Position::compute_non_pawn_material(Color c) const { Value result = Value(0); - Square s; for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) { Bitboard b = pieces_of_color_and_type(c, pt); - while(b) + while (b) { - s = pop_1st_bit(&b); - assert(piece_on(s) == piece_of_color_and_type(c, pt)); + assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt)); + pop_1st_bit(&b); result += piece_value_midgame(pt); } } @@ -1833,21 +1829,6 @@ Value Position::compute_non_pawn_material(Color c) const { } -/// Position::is_mate() returns true or false depending on whether the -/// side to move is checkmated. Note that this function is currently very -/// slow, and shouldn't be used frequently inside the search. - -bool Position::is_mate() const { - - if (is_check()) - { - MovePicker mp = MovePicker(*this, false, MOVE_NONE, EmptySearchStack, Depth(0)); - return mp.get_next_move() == MOVE_NONE; - } - return false; -} - - /// 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. @@ -1872,21 +1853,25 @@ bool Position::is_draw() const { } +/// Position::is_mate() returns true or false depending on whether the +/// side to move is checkmated. + +bool Position::is_mate() const { + + MoveStack moves[256]; + + return is_check() && !generate_evasions(*this, moves, pinned_pieces(sideToMove)); +} + + /// Position::has_mate_threat() tests whether a given color has a mate in one -/// from the current position. This function is quite slow, but it doesn't -/// matter, because it is currently only called from PV nodes, which are rare. +/// from the current position. bool Position::has_mate_threat(Color c) { StateInfo st1, st2; Color stm = side_to_move(); - // The following lines are useless and silly, but prevents gcc from - // emitting a stupid warning stating that u1.lastMove and u1.epSquare might - // be used uninitialized. - st1.lastMove = st->lastMove; - st1.epSquare = st->epSquare; - if (is_check()) return false; @@ -1897,18 +1882,26 @@ bool Position::has_mate_threat(Color c) { MoveStack mlist[120]; int count; bool result = false; + Bitboard dc = discovered_check_candidates(sideToMove); + Bitboard pinned = pinned_pieces(sideToMove); - // Generate legal moves - count = generate_legal_moves(*this, mlist); + // Generate pseudo-legal non-capture and capture check moves + count = generate_non_capture_checks(*this, mlist, dc); + count += generate_captures(*this, mlist + count); // Loop through the moves, and see if one of them is mate for (int i = 0; i < count; i++) { - do_move(mlist[i].move, st2); + Move move = mlist[i].move; + + if (!pl_move_is_legal(move, pinned)) + continue; + + do_move(move, st2); if (is_mate()) result = true; - undo_move(mlist[i].move); + undo_move(move); } // Undo null move, if necessary @@ -1978,7 +1971,7 @@ void Position::init_piece_square_tables() { /// the white and black sides reversed. This is only useful for debugging, /// especially for finding evaluation symmetry bugs. -void Position::flipped_copy(const Position &pos) { +void Position::flipped_copy(const Position& pos) { assert(pos.is_ok()); @@ -2029,8 +2022,8 @@ void Position::flipped_copy(const Position &pos) { st->egValue = compute_value(); // Material - npMaterial[WHITE] = compute_non_pawn_material(WHITE); - npMaterial[BLACK] = compute_non_pawn_material(BLACK); + st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); + st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); assert(is_ok()); } @@ -2166,10 +2159,10 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) (*failedStep)++; if (debugNonPawnMaterial) { - if (npMaterial[WHITE] != compute_non_pawn_material(WHITE)) + if (st->npMaterial[WHITE] != compute_non_pawn_material(WHITE)) return false; - if (npMaterial[BLACK] != compute_non_pawn_material(BLACK)) + if (st->npMaterial[BLACK] != compute_non_pawn_material(BLACK)) return false; }