X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=058fab66b13940b2db943aef8548c46b63d1e936;hp=1fe723aec461e20a303582484349b9696ca9c552;hb=94b9c65e09b5d396bebb29b62d9979139b5fbdfa;hpb=dddaeff7d8d4a0c255310d054a53066296e71004 diff --git a/src/position.cpp b/src/position.cpp index 1fe723ae..058fab66 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 @@ -22,10 +22,13 @@ //// Includes //// +#include #include #include #include +#include #include +#include #include "bitcount.h" #include "mersenne.h" @@ -38,37 +41,99 @@ #include "ucioption.h" using std::string; +using std::cout; +using std::endl; +static inline bool isZero(char c) { return c == '0'; } + +struct PieceLetters : std::map { + + PieceLetters() { + + operator[]('K') = WK; operator[]('k') = BK; + operator[]('Q') = WQ; operator[]('q') = BQ; + operator[]('R') = WR; operator[]('r') = BR; + operator[]('B') = WB; operator[]('b') = BB; + operator[]('N') = WN; operator[]('n') = BN; + operator[]('P') = WP; operator[]('p') = BP; + operator[](' ') = PIECE_NONE; operator[]('.') = PIECE_NONE_DARK_SQ; + } + + char from_piece(Piece p) const { + + std::map::const_iterator it; + for (it = begin(); it != end(); ++it) + if (it->second == p) + return it->first; + + assert(false); + return 0; + } +}; //// //// 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; +static PieceLetters pieceLetters; -//// -//// Functions -//// /// Constructors -Position::Position(const Position& pos) { - copy(pos); +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::Position(const string& fen) { + +/// Position c'tors. Here we always create a copy of the original position +/// or the FEN string, we want the new born Position object do not depend +/// on any external data so we detach state pointer from the source one. + +Position::Position(int th) : threadID(th) {} + +Position::Position(const Position& pos, int th) { + + memcpy(this, &pos, sizeof(Position)); + detach(); // Always detach() in copy c'tor to avoid surprises + threadID = th; +} + +Position::Position(const string& fen, int th) { + from_fen(fen); + threadID = th; +} + + +/// 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 } @@ -77,132 +142,99 @@ Position::Position(const string& fen) { /// correct (this is assumed to be the responsibility of the GUI). void Position::from_fen(const string& fen) { +/* + A FEN string defines a particular position using only the ASCII character set. - static const string pieceLetters = "KQRBNPkqrbnp"; - static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP }; + A FEN string contains six fields. The separator between fields is a space. The fields are: - clear(); + 1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending + with rank 1; within each rank, the contents of each square are described from file a through file h. + Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken + from the standard English names. White pieces are designated using upper-case letters ("PNBRQK") + while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number + of blank squares), and "/" separate ranks. - // Board + 2) Active color. "w" means white moves next, "b" means black. + + 3) Castling availability. If neither side can castle, this is "-". Otherwise, this has one or more + letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle + kingside), and/or "q" (Black can castle queenside). + + 4) En passant target square in algebraic notation. If there's no en passant target square, this is "-". + If a pawn has just made a 2-square move, this is the position "behind" the pawn. This is recorded + regardless of whether there is a pawn in position to make an en passant capture. + + 5) Halfmove clock: This is the number of halfmoves since the last pawn advance or capture. This is used + to determine if a draw can be claimed under the fifty-move rule. + + 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move. +*/ + + char token; + std::istringstream ss(fen); Rank rank = RANK_8; File file = FILE_A; - size_t i = 0; - for ( ; fen[i] != ' '; i++) + + clear(); + + // 1. Piece placement field + while (ss.get(token) && token != ' ') { - if (isdigit(fen[i])) + if (isdigit(token)) { - // Skip the given number of files - file += (fen[i] - '1' + 1); + file += File(token - '0'); // Skip the given number of files continue; } - else if (fen[i] == '/') + else if (token == '/') { file = FILE_A; rank--; continue; } - size_t idx = pieceLetters.find(fen[i]); - if (idx == string::npos) - { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - Square square = make_square(file, rank); - put_piece(pieces[idx], square); + + if (pieceLetters.find(token) == pieceLetters.end()) + goto incorrect_fen; + + put_piece(pieceLetters[token], make_square(file, rank)); file++; } - // Side to move - i++; - if (fen[i] != 'w' && fen[i] != 'b') - { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - sideToMove = (fen[i] == 'w' ? WHITE : BLACK); + // 2. Active color + if (!ss.get(token) || (token != 'w' && token != 'b')) + goto incorrect_fen; - // Castling rights - i++; - if (fen[i] != ' ') + sideToMove = (token == 'w' ? WHITE : BLACK); + + if (!ss.get(token) || token != ' ') + goto incorrect_fen; + + // 3. Castling availability + while (ss.get(token) && token != ' ') { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } + if (token == '-') + continue; - 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; - } - } - 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 { - std::cout << "Error in FEN at character " << i << std::endl; - return; - } - i++; + if (!set_castling_rights(token)) + goto incorrect_fen; } - // Skip blanks - while (fen[i] == ' ') - i++; + // 4. En passant square -- ignore if no capture is possible + char col, row; + if ( (ss.get(col) && (col >= 'a' && col <= 'h')) + && (ss.get(row) && (row == '3' || row == '6'))) + { + Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row)); + Color them = opposite_color(sideToMove); - // En passant square - 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)); + if (attacks_from(fenEpSquare, them) & pieces(PAWN, sideToMove)) + st->epSquare = fenEpSquare; + } - // Various initialisation - for (Square sq = SQ_A1; sq <= SQ_H8; sq++) - castleRightsMask[sq] = ALL_CASTLES; + // 5-6. Halfmove clock and fullmove number are not parsed - castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO|WHITE_OOO); - castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO|BLACK_OOO); + // Various initialisations + castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO; + castleRightsMask[make_square(initialKFile, RANK_8)] ^= BLACK_OO | BLACK_OOO; castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO; castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO; castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO; @@ -213,60 +245,126 @@ 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); + return; + +incorrect_fen: + cout << "Error in FEN string: " << fen << endl; +} + + +/// Position::set_castling_rights() sets castling parameters castling avaiability. +/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN +/// that uses the letters of the columns on which the rooks began the game instead +/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is +/// associated with the castling right, the traditional castling tag will be replaced +/// by the file letter of the involved rook as for the Shredder-FEN. + +bool Position::set_castling_rights(char token) { + + Color c = token >= 'a' ? BLACK : WHITE; + Square sqA = (c == WHITE ? SQ_A1 : SQ_A8); + Square sqH = (c == WHITE ? SQ_H1 : SQ_H8); + Piece rook = (c == WHITE ? WR : BR); + + initialKFile = square_file(king_square(c)); + token = char(toupper(token)); + + if (token == 'K') + { + for (Square sq = sqH; sq >= sqA; sq--) + if (piece_on(sq) == rook) + { + allow_oo(c); + initialKRFile = square_file(sq); + break; + } + } + else if (token == 'Q') + { + for (Square sq = sqA; sq <= sqH; sq++) + if (piece_on(sq) == rook) + { + allow_ooo(c); + initialQRFile = square_file(sq); + break; + } + } + else if (token >= 'A' && token <= 'H') + { + File rookFile = File(token - 'A') + FILE_A; + if (rookFile < initialKFile) + { + allow_ooo(c); + initialQRFile = rookFile; + } + else + { + allow_oo(c); + initialKRFile = rookFile; + } + } + else return false; + + return true; } -/// Position::to_fen() converts the position object to a FEN string. This is -/// probably only useful for debugging. +/// Position::to_fen() returns a FEN representation of the position. In case +/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function. const string Position::to_fen() const { - static const string pieceLetters = " PNBRQK pnbrqk"; string fen; - int skip; + Square sq; + char emptyCnt = '0'; for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - skip = 0; for (File file = FILE_A; file <= FILE_H; file++) { - Square sq = make_square(file, rank); - if (!square_is_occupied(sq)) - { skip++; - continue; - } - if (skip > 0) + sq = make_square(file, rank); + + if (square_is_occupied(sq)) { - fen += (char)skip + '0'; - skip = 0; - } - fen += pieceLetters[piece_on(sq)]; + fen += emptyCnt; + fen += pieceLetters.from_piece(piece_on(sq)); + emptyCnt = '0'; + } else + emptyCnt++; } - if (skip > 0) - fen += (char)skip + '0'; - - fen += (rank > RANK_1 ? '/' : ' '); + fen += emptyCnt; + fen += '/'; + emptyCnt = '0'; } - fen += (sideToMove == WHITE ? "w " : "b "); - if (st->castleRights != NO_CASTLES) + + fen.erase(std::remove_if(fen.begin(), fen.end(), isZero), fen.end()); + fen.erase(--fen.end()); + fen += (sideToMove == WHITE ? " w " : " b "); + + if (st->castleRights != CASTLES_NONE) { - 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 - fen += '-'; + const bool Chess960 = initialKFile != FILE_E + || initialQRFile != FILE_A + || initialKRFile != FILE_H; - fen += ' '; - if (ep_square() != SQ_NONE) - fen += square_to_string(ep_square()); - else + if (can_castle_kingside(WHITE)) + fen += Chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K'; + + if (can_castle_queenside(WHITE)) + fen += Chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q'; + + if (can_castle_kingside(BLACK)) + fen += Chess960 ? file_to_char(initialKRFile) : 'k'; + + if (can_castle_queenside(BLACK)) + fen += Chess960 ? file_to_char(initialQRFile) : 'q'; + } else fen += '-'; + fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square())); return fen; } @@ -274,52 +372,42 @@ const string Position::to_fen() const { /// Position::print() prints an ASCII representation of the position to /// the standard output. If a move is given then also the san is print. -void Position::print(Move m) const { +void Position::print(Move move) const { - static const string pieceLetters = " PNBRQK PNBRQK ."; + const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n"; + static bool requestPending = false; // Check for reentrancy, as example when called from inside // MovePicker that is used also here in move_to_san() - if (RequestPending) + if (requestPending) return; - RequestPending = true; + requestPending = true; - std::cout << std::endl; - if (m != MOVE_NONE) + if (move) { - string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); - std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl; + Position p(*this, thread()); + string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : ""); + cout << "\nMove is: " << dd << move_to_san(p, move); } + for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl; + cout << dottedLine << '|'; for (File file = FILE_A; file <= FILE_H; file++) { Square sq = make_square(file, rank); + char c = (color_of_piece_on(sq) == BLACK ? '=' : ' '); Piece piece = piece_on(sq); - if (piece == EMPTY && square_color(sq) == WHITE) - piece = NO_PIECE; - char col = (color_of_piece_on(sq) == BLACK ? '=' : ' '); - std::cout << '|' << col << pieceLetters[piece] << col; + if (piece == PIECE_NONE && square_color(sq) == DARK) + piece = PIECE_NONE_DARK_SQ; + + cout << c << pieceLetters.from_piece(piece) << c << '|'; } - std::cout << '|' << std::endl; } - std::cout << "+---+---+---+---+---+---+---+---+" << std::endl - << "Fen is: " << to_fen() << std::endl - << "Key is: " << st->key << std::endl; - - RequestPending = false; -} - - -/// 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 + cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl; + requestPending = false; } @@ -327,21 +415,20 @@ void Position::copy(const Position& pos) { /// 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 = (pieces(ROOK, QUEEN, FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]) - | (pieces(BISHOP, QUEEN, 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; @@ -362,7 +449,8 @@ 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 { @@ -372,7 +460,8 @@ 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 { @@ -458,19 +547,11 @@ void Position::find_checkers() { /// 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)) @@ -482,7 +563,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(color_of_piece_on(from) == us); 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)) @@ -496,7 +577,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(to == ep_square()); assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); - assert(piece_on(to) == EMPTY); + assert(piece_on(to) == PIECE_NONE); clear_bit(&b, from); clear_bit(&b, capsq); @@ -519,166 +600,128 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } +/// 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); +} + + /// Position::move_is_check() tests whether a pseudo-legal move is a check 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(attacks_from(ksq, them), to)) // Normal check? - return true; - - if ( dcCandidates // Discovered check? - && bit_is_set(dcCandidates, from) - && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) + // 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 (move_is_promotion(m)) // Promotion with check? - { - Bitboard b = occupied_squares(); - clear_bit(&b, from); - - switch (move_promotion_piece(m)) - { - case KNIGHT: - return bit_is_set(attacks_from(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) & pieces(ROOK, QUEEN, us)) - ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, 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(attacks_from(ksq), to); - - case BISHOP: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(ksq), to)); - - case ROOK: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)); - - case QUEEN: - // Discovered checks are impossible! - assert(!bit_is_set(dcCandidates, from)); - return ( (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)) - || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(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(attacks_from(ksq), to)) // slow, try to early skip - set_bit(pCheckersBB, to); - - else if ( Piece != KING - && !Slider - && bit_is_set(Piece == PAWN ? attacks_from(ksq, opposite_color(sideToMove)) - : attacks_from(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) |= (attacks_from(ksq) & pieces(ROOK, QUEEN, side_to_move())); + Square kfrom, kto, rfrom, rto; + kfrom = from; + rfrom = to; - if (Piece != BISHOP) - (*pCheckersBB) |= (attacks_from(ksq) & pieces(BISHOP, QUEEN, 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; } @@ -688,24 +731,25 @@ 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; + Key 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, pliesFromNull; + Key pawnKey, materialKey; + int castleRights, rule50, gamePly, pliesFromNull; Square epSquare; - Value mgValue, egValue; + Score value; Value npMaterial[2]; }; @@ -715,8 +759,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = key; - gamePly++; + history[st->gamePly++] = key; // Update side to move key ^= zobSideToMove; @@ -742,16 +785,15 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { 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); - st->capture = ep ? PAWN : type_of_piece_on(to); - - if (st->capture) - do_capture_move(key, st->capture, them, to, ep); + if (capture) + do_capture_move(key, capture, them, to, ep); // Update hash key key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; @@ -774,7 +816,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { } // Prefetch TT access as soon as we know key is updated - TT.prefetch(key); + prefetch((char*)TT.first_entry(key)); // Move the piece Bitboard move_bb = make_move_bb(from, to); @@ -783,7 +825,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares board[to] = board[from]; - board[from] = EMPTY; + board[from] = PIECE_NONE; // Update piece lists, note that index[from] is not updated and // becomes stale. This works as long as index[] is accessed just @@ -801,7 +843,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { 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 ((to ^ from) == 16) { if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) { @@ -809,81 +851,85 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { 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 piece counts + pieceCount[us][promotion]++; + pieceCount[us][PAWN]--; + + // Update material key + st->materialKey ^= zobrist[us][PAWN][pieceCount[us][PAWN]]; + st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]-1]; + + // 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 incremental scores - st->mgValue += pst_delta(piece, from, to); - st->egValue += pst_delta(piece, from, to); + st->value += pst_delta(piece, from, to); - 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->mgValue -= pst(us, PAWN, to); - st->mgValue += pst(us, promotion, to); - st->egValue -= pst(us, PAWN, to); - st->egValue += pst(us, promotion, to); - - // Update material - st->npMaterial[us] += piece_value_midgame(promotion); - } + // Set capture piece + st->capturedType = capture; // Update the key with the final value st->key = key; // Update checkers bitboard, piece must be already moved - if (ep | pm) - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); - else + st->checkersBB = EmptyBoardBB; + + if (moveIsCheck) { - st->checkersBB = EmptyBoardBB; - Square ksq = king_square(them); - switch (pt) + if (ep | pm) + st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); + else { - 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; + // 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 sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -892,23 +938,31 @@ 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(Bitboard& key, PieceType capture, Color them, Square to, bool ep) { +void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) { assert(capture != KING); Square capsq = to; - if (ep) // en passant ? + // If the captured piece was a pawn, update pawn hash key, + // otherwise update non-pawn material. + if (capture == PAWN) { - capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S); + 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)); + assert(to == st->epSquare); + assert(relative_rank(opposite_color(them), to) == RANK_6); + assert(piece_on(to) == PIECE_NONE); + assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); - board[capsq] = EMPTY; + board[capsq] = PIECE_NONE; + } + st->pawnKey ^= zobrist[them][PAWN][capsq]; } + else + st->npMaterial[them] -= piece_value_midgame(capture); // Remove captured piece clear_bit(&(byColorBB[them]), capsq); @@ -919,22 +973,14 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ key ^= zobrist[them][capture][capsq]; // Update incremental scores - st->mgValue -= pst(them, capture, capsq); - st->egValue -= pst(them, capture, capsq); - - // 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 - st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]]; + st->value -= pst(them, capture, capsq); // Update piece count pieceCount[them][capture]--; + // Update material hash key + st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + // Update piece list, move the last piece at index[capsq] position // // WARNING: This is a not perfectly revresible operation. When we @@ -966,7 +1012,7 @@ void Position::do_castle_move(Move m) { Color them = opposite_color(us); // Reset capture field - st->capture = NO_PIECE_TYPE; + st->capturedType = PIECE_TYPE_NONE; // Find source squares for king and rook Square kfrom = move_from(m); @@ -1001,11 +1047,11 @@ void Position::do_castle_move(Move m) { set_bit(&(byColorBB[us]), rto); set_bit(&(byTypeBB[ROOK]), rto); 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[kfrom] = board[rfrom] = PIECE_NONE; board[kto] = king; board[rto] = rook; @@ -1017,10 +1063,8 @@ void Position::do_castle_move(Move m) { index[rto] = tmp; // Update incremental scores - st->mgValue += pst_delta(king, kfrom, kto); - st->egValue += pst_delta(king, kfrom, kto); - st->mgValue += pst_delta(rook, rfrom, rto); - st->egValue += pst_delta(rook, rfrom, 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]; @@ -1046,9 +1090,7 @@ void Position::do_castle_move(Move m) { // Finish sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -1062,7 +1104,6 @@ void Position::undo_move(Move m) { assert(is_ok()); assert(move_is_ok(m)); - gamePly--; sideToMove = opposite_color(sideToMove); if (move_is_castle(m)) @@ -1112,7 +1153,6 @@ void Position::undo_move(Move m) { pieceList[us][PAWN][index[to]] = to; } - // Put the piece back at the source square Bitboard move_bb = make_move_bb(to, from); do_move_bb(&(byColorBB[us]), move_bb); @@ -1120,35 +1160,35 @@ void Position::undo_move(Move m) { do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares board[from] = piece_of_color_and_type(us, pt); - board[to] = EMPTY; + board[to] = PIECE_NONE; // Update piece list index[from] = index[to]; pieceList[us][pt][index[from]] = from; - if (st->capture) + if (st->capturedType) { Square capsq = to; if (ep) capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - assert(st->capture != KING); + assert(st->capturedType != KING); assert(!ep || square_is_empty(capsq)); // Restore the captured piece set_bit(&(byColorBB[them]), capsq); - set_bit(&(byTypeBB[st->capture]), capsq); + set_bit(&(byTypeBB[st->capturedType]), capsq); set_bit(&(byTypeBB[0]), capsq); - board[capsq] = piece_of_color_and_type(them, st->capture); + board[capsq] = piece_of_color_and_type(them, st->capturedType); // Update piece count - pieceCount[them][st->capture]++; + pieceCount[them][st->capturedType]++; // 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; + index[capsq] = pieceCount[them][st->capturedType] - 1; + pieceList[them][st->capturedType][index[capsq]] = capsq; } // Finally point our state pointer back to the previous state @@ -1190,7 +1230,7 @@ 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: clear_bit(&(byColorBB[us]), kto); clear_bit(&(byTypeBB[KING]), kto); @@ -1198,7 +1238,7 @@ void Position::undo_castle_move(Move m) { clear_bit(&(byColorBB[us]), rto); clear_bit(&(byTypeBB[ROOK]), rto); clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares - + // Put pieces on source squares: set_bit(&(byColorBB[us]), kfrom); set_bit(&(byTypeBB[KING]), kfrom); @@ -1208,7 +1248,7 @@ void Position::undo_castle_move(Move m) { set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares // Update board - board[rto] = board[kto] = EMPTY; + board[rto] = board[kto] = PIECE_NONE; board[rfrom] = piece_of_color_and_type(us, ROOK); board[kfrom] = piece_of_color_and_type(us, KING); @@ -1240,31 +1280,27 @@ void Position::do_null_move(StateInfo& backupSt) { // a backup storage not as a new state to be used. backupSt.key = st->key; backupSt.epSquare = st->epSquare; - 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 // detect repetition draws. - history[gamePly] = st->key; + history[st->gamePly++] = st->key; // Update the necessary information if (st->epSquare != SQ_NONE) st->key ^= zobEp[st->epSquare]; st->key ^= zobSideToMove; - TT.prefetch(st->key); + prefetch((char*)TT.first_entry(st->key)); sideToMove = opposite_color(sideToMove); st->epSquare = SQ_NONE; st->rule50++; st->pliesFromNull = 0; - gamePly++; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; } @@ -1279,15 +1315,14 @@ void Position::undo_null_move() { StateInfo* backupSt = st->previous; st->key = backupSt->key; st->epSquare = backupSt->epSquare; - st->mgValue = backupSt->mgValue; - st->egValue = backupSt->egValue; + st->value = backupSt->value; st->previous = backupSt->previous; st->pliesFromNull = backupSt->pliesFromNull; // Update the necessary information sideToMove = opposite_color(sideToMove); st->rule50--; - gamePly--; + st->gamePly--; } @@ -1300,13 +1335,13 @@ void Position::undo_null_move() { int Position::see(Square to) const { assert(square_is_ok(to)); - return see(SQ_NONE, to, false); + return see(SQ_NONE, to); } int Position::see(Move m) const { assert(move_is_ok(m)); - return see(move_from(m), move_to(m), false); + return see(move_from(m), move_to(m)); } int Position::see_sign(Move m) const { @@ -1316,16 +1351,16 @@ int Position::see_sign(Move m) const { 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; + // Early return if SEE cannot be negative because captured piece value + // is not less then capturing one. Note that king moves always return + // here because king midgame value is set to 0. + if (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from)) + return 1; - return see(from, to, true); + return see(from, to); } -int Position::see(Square from, Square to, bool shortcut) const { +int Position::see(Square from, Square to) const { // Material values static const int seeValues[18] = { @@ -1337,9 +1372,7 @@ int Position::see(Square from, Square to, bool shortcut) const { }; Bitboard attackers, stmAttackers, b; - int pieceDiff = 0; - assert(!shortcut || from != SQ_NONE); assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1356,26 +1389,10 @@ int Position::see(Square from, Square to, bool shortcut) const { if (type_of_piece(piece) == KING) return seeValues[capture]; - // If captured piece is defended by enemy pawns or knights then SEE is negative - // when captured piece value does not compensate the lost of capturing one. - if (shortcut) - { - pieceDiff = seeValues[piece] - seeValues[capture]; - - if ( pieceDiff > seeValues[PAWN] - &&(attacks_from(to, us) & pieces(PAWN, them))) - return -(pieceDiff - seeValues[PAWN] / 2); - - if ( pieceDiff > seeValues[KNIGHT] - && pieces(KNIGHT, them) - &&(pieces(KNIGHT, them) & attacks_from(to))) - return -(pieceDiff - seeValues[KNIGHT] / 2); - } - // Handle en passant moves if (st->epSquare == to && type_of_piece_on(from) == PAWN) { - assert(capture == EMPTY); + assert(capture == PIECE_NONE); Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S); capture = piece_on(capQq); @@ -1442,15 +1459,6 @@ int Position::see(Square from, Square to, bool shortcut) const { for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) assert(pt < KING); - // If captured piece is defended by an enemy piece then SEE is negative - // if captured piece value does not compensate the lost of capturing one. - if (pieceDiff > seeValues[pt]) - { - assert(shortcut); - return -(pieceDiff - seeValues[pt] / 2); - } else - pieceDiff = 0; // Only first cycle - // Remove the attacker we just found from the 'attackers' bitboard, // and scan for new X-ray attacks behind the attacker. b = stmAttackers & pieces(pt); @@ -1489,19 +1497,6 @@ int Position::see(Square from, Square to, bool shortcut) 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. @@ -1510,6 +1505,7 @@ void Position::clear() { st = &startState; memset(st, 0, sizeof(StateInfo)); st->epSquare = SQ_NONE; + startPosPlyCounter = 0; memset(byColorBB, 0, sizeof(Bitboard) * 2); memset(byTypeBB, 0, sizeof(Bitboard) * 8); @@ -1517,14 +1513,16 @@ void Position::clear() { memset(index, 0, sizeof(int) * 64); for (int i = 0; i < 64; i++) - board[i] = EMPTY; + board[i] = PIECE_NONE; for (int i = 0; i < 8; i++) for (int j = 0; j < 16; j++) pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; + for (Square sq = SQ_A1; sq <= SQ_H8; sq++) + castleRightsMask[sq] = ALL_CASTLES; + sideToMove = WHITE; - gamePly = 0; initialKFile = FILE_E; initialKRFile = FILE_H; initialQRFile = FILE_A; @@ -1539,9 +1537,13 @@ void Position::clear() { void Position::reset_game_ply() { - gamePly = 0; + st->gamePly = 0; } +void Position::inc_startpos_ply_counter() { + + startPosPlyCounter++; +} /// Position::put_piece() puts a piece on the given square of the board, /// updating the board array, bitboards, and piece counts. @@ -1620,7 +1622,7 @@ Key Position::compute_pawn_key() const { for (Color c = WHITE; c <= BLACK; c++) { b = pieces(PAWN, c); - while(b) + while (b) { s = pop_1st_bit(&b); result ^= zobrist[c][PAWN][s]; @@ -1643,8 +1645,8 @@ Key Position::compute_material_key() const { for (PieceType pt = PAWN; pt <= QUEEN; pt++) { int count = piece_count(c, pt); - for (int i = 0; i <= count; i++) - result ^= zobMaterial[c][pt][i]; + for (int i = 0; i < count; i++) + result ^= zobrist[c][pt][i]; } return result; } @@ -1654,10 +1656,9 @@ 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; @@ -1665,16 +1666,15 @@ Value Position::compute_value() const { for (PieceType pt = PAWN; pt <= KING; pt++) { b = pieces(pt, c); - while(b) + 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; } @@ -1686,7 +1686,7 @@ Value Position::compute_value() const { Value Position::compute_non_pawn_material(Color c) const { - Value result = Value(0); + Value result = VALUE_ZERO; for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) { @@ -1705,6 +1705,7 @@ 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 { @@ -1718,8 +1719,8 @@ bool Position::is_draw() const { return true; // Draw by repetition? - for (int i = 2; i < Min(Min(gamePly, st->rule50), st->pliesFromNull); i += 2) - if (history[gamePly - i] == st->key) + for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2) + if (history[st->gamePly - i] == st->key) return true; return false; @@ -1732,109 +1733,89 @@ bool Position::is_draw() const { bool Position::is_mate() const { MoveStack moves[256]; - - return is_check() && (generate_evasions(*this, moves, pinned_pieces(sideToMove)) == moves); + return is_check() && (generate_moves(*this, moves) == moves); } -/// Position::has_mate_threat() tests whether a given color has a mate in one -/// from the current position. +/// Position::has_mate_threat() tests whether the side to move is under +/// a threat of being mated in one from the current position. -bool Position::has_mate_threat(Color c) { +bool Position::has_mate_threat() { + MoveStack mlist[256], *last, *cur; StateInfo st1, st2; - Color stm = side_to_move(); + bool mateFound = false; + // If we are under check it's up to evasions to do the job if (is_check()) return false; - // If the input color is not equal to the side to move, do a null move - if (c != stm) - do_null_move(st1); + // First pass the move to our opponent doing a null move + do_null_move(st1); - MoveStack mlist[120]; - bool result = false; - Bitboard dc = discovered_check_candidates(sideToMove); - Bitboard pinned = pinned_pieces(sideToMove); - - // Generate pseudo-legal non-capture and capture check moves - MoveStack* last = generate_non_capture_checks(*this, mlist, dc); + // Then generate pseudo-legal moves that give check + 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 (MoveStack* cur = mlist; cur != last; cur++) + // Loop through the moves, and see if one of them gives mate + Bitboard pinned = pinned_pieces(sideToMove); + CheckInfo ci(*this); + for (cur = mlist; cur != last && !mateFound; cur++) { Move move = cur->move; - if (!pl_move_is_legal(move, pinned)) + if ( !pl_move_is_legal(move, pinned) + || !move_is_check(move, ci)) continue; - do_move(move, st2); + do_move(move, st2, ci, true); + if (is_mate()) - result = true; + mateFound = true; undo_move(move); } - // Undo null move, if necessary - if (c != stm) - undo_null_move(); - - return result; + undo_null_move(); + return mateFound; } -/// Position::init_zobrist() is a static member function which initializes the -/// various arrays used to compute hash keys. +/// Position::init_zobrist() is a static member function which initializes at +/// startup the various arrays used to compute hash keys. void Position::init_zobrist() { - for (int i = 0; i < 2; i++) - for (int j = 0; j < 8; j++) - for (int k = 0; k < 64; k++) - zobrist[i][j][k] = Key(genrand_int64()); - - for (int i = 0; i < 64; i++) - zobEp[i] = Key(genrand_int64()); + int i,j, k; - for (int i = 0; i < 16; i++) - zobCastle[i] = genrand_int64(); + for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++) + zobrist[i][j][k] = Key(genrand_int64()); - zobSideToMove = genrand_int64(); + for (i = 0; i < 64; i++) + zobEp[i] = Key(genrand_int64()); - for (int i = 0; i < 2; i++) - for (int j = 0; j < 8; j++) - for (int k = 0; k < 16; k++) - zobMaterial[i][j][k] = (k > 0)? Key(genrand_int64()) : Key(0LL); + for (i = 0; i < 16; i++) + zobCastle[i] = Key(genrand_int64()); - for (int i = 0; i < 16; i++) - zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL); + zobSideToMove = Key(genrand_int64()); + zobExclusion = Key(genrand_int64()); } /// Position::init_piece_square_tables() initializes the piece square tables. -/// This is a two-step operation: First, the white halves of the tables are -/// copied from the MgPST[][] and EgPST[][] arrays, with a small random number -/// added to each entry if the "Randomness" UCI parameter is non-zero. -/// Second, the black halves of the tables are initialized by mirroring -/// and changing the sign of the corresponding white scores. +/// This is a two-step operation: First, the white halves of the tables are +/// copied from the MgPST[][] and EgPST[][] arrays. Second, the black halves +/// of the tables are initialized by mirroring and changing the sign of the +/// corresponding white scores. void Position::init_piece_square_tables() { - int r = get_option_value_int("Randomness"), i; for (Square s = SQ_A1; s <= SQ_H8; s++) 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], EgPST[p][s]); 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)]; } @@ -1847,6 +1828,7 @@ void Position::flipped_copy(const Position& pos) { assert(pos.is_ok()); clear(); + threadID = pos.thread(); // Board for (Square s = SQ_A1; s <= SQ_H8; s++) @@ -1866,9 +1848,6 @@ void Position::flipped_copy(const Position& pos) { initialKRFile = pos.initialKRFile; initialQRFile = pos.initialQRFile; - for (Square sq = SQ_A1; sq <= SQ_H8; sq++) - castleRightsMask[sq] = ALL_CASTLES; - castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO | WHITE_OOO); castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO | BLACK_OOO); castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO; @@ -1889,8 +1868,7 @@ 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); @@ -1917,6 +1895,7 @@ 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; @@ -2017,14 +1996,8 @@ 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)++; @@ -2048,9 +2021,9 @@ bool Position::is_ok(int* failedStep) const { 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; @@ -2059,6 +2032,25 @@ 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; }