X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=1a8c7e00d6a0bc24af2e44c395a70fb9eb6c1d4b;hp=57d6dc09bce917c7d9014f1d31340b6ed6134dd8;hb=d3608c4e79a29110f4c4a369d7207c6dd8e01f34;hpb=0439a79566d03065317b2025b9b479b9ae9f2d65 diff --git a/src/position.cpp b/src/position.cpp index 57d6dc09..1a8c7e00 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) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2013 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 @@ -19,12 +19,14 @@ #include #include +#include #include #include #include #include "bitcount.h" #include "movegen.h" +#include "notation.h" #include "position.h" #include "psqtab.h" #include "rkiss.h" @@ -35,43 +37,105 @@ using std::string; using std::cout; using std::endl; -Key Position::zobrist[2][8][64]; -Key Position::zobEp[8]; -Key Position::zobCastle[16]; -Key Position::zobSideToMove; -Key Position::zobExclusion; - -Score Position::pieceSquareTable[16][64]; - -// Material values arrays, indexed by Piece -const Value PieceValueMidgame[17] = { - VALUE_ZERO, - PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, - RookValueMidgame, QueenValueMidgame, - VALUE_ZERO, VALUE_ZERO, VALUE_ZERO, - PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, - RookValueMidgame, QueenValueMidgame -}; - -const Value PieceValueEndgame[17] = { - VALUE_ZERO, - PawnValueEndgame, KnightValueEndgame, BishopValueEndgame, - RookValueEndgame, QueenValueEndgame, - VALUE_ZERO, VALUE_ZERO, VALUE_ZERO, - PawnValueEndgame, KnightValueEndgame, BishopValueEndgame, - RookValueEndgame, QueenValueEndgame -}; +static const string PieceToChar(" PNBRQK pnbrqk"); + +CACHE_LINE_ALIGNMENT + +Score pieceSquareTable[PIECE_NB][SQUARE_NB]; +Value PieceValue[PHASE_NB][PIECE_NB] = { +{ VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg }, +{ VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } }; + +namespace Zobrist { + +Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; +Key enpassant[FILE_NB]; +Key castle[CASTLE_RIGHT_NB]; +Key side; +Key exclusion; + +/// init() initializes at startup the various arrays used to compute hash keys +/// and the piece square tables. The latter is a two-step operation: First, the +/// white halves of the tables are copied from PSQT[] tables. Second, the black +/// halves of the tables are initialized by flipping and changing the sign of +/// the white scores. + +void init() { + + RKISS rk; + + for (Color c = WHITE; c <= BLACK; c++) + for (PieceType pt = PAWN; pt <= KING; pt++) + for (Square s = SQ_A1; s <= SQ_H8; s++) + psq[c][pt][s] = rk.rand(); + + for (File f = FILE_A; f <= FILE_H; f++) + enpassant[f] = rk.rand(); + + for (int cr = CASTLES_NONE; cr <= ALL_CASTLES; cr++) + { + Bitboard b = cr; + while (b) + { + Key k = castle[1ULL << pop_lsb(&b)]; + castle[cr] ^= k ? k : rk.rand(); + } + } + + side = rk.rand(); + exclusion = rk.rand(); + + for (PieceType pt = PAWN; pt <= KING; pt++) + { + PieceValue[MG][make_piece(BLACK, pt)] = PieceValue[MG][pt]; + PieceValue[EG][make_piece(BLACK, pt)] = PieceValue[EG][pt]; + + Score v = make_score(PieceValue[MG][pt], PieceValue[EG][pt]); + + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + pieceSquareTable[make_piece(WHITE, pt)][ s] = (v + PSQT[pt][s]); + pieceSquareTable[make_piece(BLACK, pt)][~s] = -(v + PSQT[pt][s]); + } + } +} + +} // namespace Zobrist namespace { - // Bonus for having the side to move (modified by Joona Kiiski) - const Score Tempo = make_score(48, 22); +/// next_attacker() is an helper function used by see() to locate the least +/// valuable attacker for the side to move, remove the attacker we just found +/// from the 'occupied' bitboard and scan for new X-ray attacks behind it. + +template FORCE_INLINE +PieceType next_attacker(const Bitboard* bb, const Square& to, const Bitboard& stmAttackers, + Bitboard& occupied, Bitboard& attackers) { + + if (stmAttackers & bb[Pt]) + { + Bitboard b = stmAttackers & bb[Pt]; + occupied ^= b & ~(b - 1); + + if (Pt == PAWN || Pt == BISHOP || Pt == QUEEN) + attackers |= attacks_bb(to, occupied) & (bb[BISHOP] | bb[QUEEN]); + + if (Pt == ROOK || Pt == QUEEN) + attackers |= attacks_bb(to, occupied) & (bb[ROOK] | bb[QUEEN]); + + return (PieceType)Pt; + } + return next_attacker(bb, to, stmAttackers, occupied, attackers); +} - // To convert a Piece to and from a FEN char - const string PieceToChar(" PNBRQK pnbrqk ."); +template<> FORCE_INLINE +PieceType next_attacker(const Bitboard*, const Square&, const Bitboard&, Bitboard&, Bitboard&) { + return KING; // No need to update bitboards, it is the last cycle } +} // namespace + /// CheckInfo c'tor @@ -92,33 +156,28 @@ CheckInfo::CheckInfo(const Position& pos) { } -/// 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::operator=() creates a copy of 'pos'. We want the new born Position +/// object do not depend on any external data so we detach state pointer from +/// the source one. -void Position::copy(const Position& pos, int th) { +Position& Position::operator=(const Position& pos) { memcpy(this, &pos, sizeof(Position)); startState = *st; st = &startState; - threadID = th; nodes = 0; assert(pos_is_ok()); -} - -Position::Position(const string& fen, bool isChess960, int th) { - from_fen(fen, isChess960); - threadID = th; + return *this; } -/// Position::from_fen() initializes the position object with the given FEN -/// string. This function is not very robust - make sure that input FENs are -/// correct (this is assumed to be the responsibility of the GUI). +/// Position::set() initializes the position object with the given FEN string. +/// This function is not very robust - make sure that input FENs are correct, +/// this is assumed to be the responsibility of the GUI. -void Position::from_fen(const string& fenStr, bool isChess960) { +void Position::set(const string& fenStr, bool isChess960, Thread* th) { /* A FEN string defines a particular position using only the ASCII character set. @@ -156,19 +215,19 @@ void Position::from_fen(const string& fenStr, bool isChess960) { char col, row, token; size_t p; Square sq = SQ_A8; - std::istringstream fen(fenStr); + std::istringstream ss(fenStr); clear(); - fen >> std::noskipws; + ss >> std::noskipws; // 1. Piece placement - while ((fen >> token) && !isspace(token)) + while ((ss >> token) && !isspace(token)) { if (isdigit(token)) sq += Square(token - '0'); // Advance the given number of files else if (token == '/') - sq = make_square(FILE_A, rank_of(sq) - Rank(2)); + sq -= Square(16); else if ((p = PieceToChar.find(token)) != string::npos) { @@ -178,16 +237,16 @@ void Position::from_fen(const string& fenStr, bool isChess960) { } // 2. Active color - fen >> token; + ss >> token; sideToMove = (token == 'w' ? WHITE : BLACK); - fen >> token; + ss >> token; // 3. Castling availability. 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 castling tag is // replaced by the file letter of the involved rook, as for the Shredder-FEN. - while ((fen >> token) && !isspace(token)) + while ((ss >> token) && !isspace(token)) { Square rsq; Color c = islower(token) ? BLACK : WHITE; @@ -201,7 +260,7 @@ void Position::from_fen(const string& fenStr, bool isChess960) { for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; rsq++) {} else if (token >= 'A' && token <= 'H') - rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + rsq = File(token - 'A') | relative_rank(c, RANK_1); else continue; @@ -210,21 +269,21 @@ void Position::from_fen(const string& fenStr, bool isChess960) { } // 4. En passant square. Ignore if no pawn capture is possible - if ( ((fen >> col) && (col >= 'a' && col <= 'h')) - && ((fen >> row) && (row == '3' || row == '6'))) + if ( ((ss >> col) && (col >= 'a' && col <= 'h')) + && ((ss >> row) && (row == '3' || row == '6'))) { - st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); + st->epSquare = File(col - 'a') | Rank(row - '1'); - if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove))) + if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN))) st->epSquare = SQ_NONE; } // 5-6. Halfmove clock and fullmove number - fen >> std::skipws >> st->rule50 >> startPosPly; + ss >> std::skipws >> st->rule50 >> gamePly; // Convert from fullmove starting from 1 to ply starting from 0, // handle also common incorrect FEN with fullmove = 0. - startPosPly = std::max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK); + gamePly = std::max(2 * (gamePly - 1), 0) + int(sideToMove == BLACK); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -234,6 +293,7 @@ void Position::from_fen(const string& fenStr, bool isChess960) { st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); chess960 = isChess960; + thisThread = th; assert(pos_is_ok()); } @@ -245,117 +305,113 @@ void Position::from_fen(const string& fenStr, bool isChess960) { void Position::set_castle_right(Color c, Square rfrom) { Square kfrom = king_square(c); - bool kingSide = kfrom < rfrom; - int cr = (kingSide ? WHITE_OO : WHITE_OOO) << c; + CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE; + CastleRight cr = make_castle_right(c, cs); st->castleRights |= cr; castleRightsMask[kfrom] |= cr; castleRightsMask[rfrom] |= cr; - castleRookSquare[cr] = rfrom; + castleRookSquare[c][cs] = rfrom; - Square kto = relative_square(c, kingSide ? SQ_G1 : SQ_C1); - Square rto = relative_square(c, kingSide ? SQ_F1 : SQ_D1); + 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) - castlePath[cr] |= s; + castlePath[c][cs] |= s; for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++) if (s != kfrom && s != rfrom) - castlePath[cr] |= s; + castlePath[c][cs] |= s; } -/// Position::to_fen() returns a FEN representation of the position. In case +/// Position::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 { +const string Position::fen() const { - std::ostringstream fen; - Square sq; - int emptyCnt; + std::ostringstream ss; for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - emptyCnt = 0; - for (File file = FILE_A; file <= FILE_H; file++) { - sq = make_square(file, rank); + Square sq = file | rank; - if (square_empty(sq)) - emptyCnt++; - else + if (is_empty(sq)) { - if (emptyCnt > 0) - { - fen << emptyCnt; - emptyCnt = 0; - } - fen << PieceToChar[piece_on(sq)]; + int emptyCnt = 1; + + for ( ; file < FILE_H && is_empty(sq++); file++) + emptyCnt++; + + ss << emptyCnt; } + else + ss << PieceToChar[piece_on(sq)]; } - if (emptyCnt > 0) - fen << emptyCnt; - if (rank > RANK_1) - fen << '/'; + ss << '/'; } - fen << (sideToMove == WHITE ? " w " : " b "); + ss << (sideToMove == WHITE ? " w " : " b "); if (can_castle(WHITE_OO)) - fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K'); + ss << (chess960 ? file_to_char(file_of(castle_rook_square(WHITE, KING_SIDE)), false) : 'K'); if (can_castle(WHITE_OOO)) - fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q'); + ss << (chess960 ? file_to_char(file_of(castle_rook_square(WHITE, QUEEN_SIDE)), false) : 'Q'); if (can_castle(BLACK_OO)) - fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k'); + ss << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK, KING_SIDE)), true) : 'k'); if (can_castle(BLACK_OOO)) - fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q'); + ss << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK, QUEEN_SIDE)), true) : 'q'); if (st->castleRights == CASTLES_NONE) - fen << '-'; + ss << '-'; - fen << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ") - << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2; + ss << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ") + << st->rule50 << " " << 1 + (gamePly - int(sideToMove == BLACK)) / 2; - return fen.str(); + return ss.str(); } -/// Position::print() prints an ASCII representation of the position to -/// the standard output. If a move is given then also the san is printed. +/// Position::pretty() returns an ASCII representation of the position to be +/// printed to the standard output together with the move's san notation. -void Position::print(Move move) const { +const string Position::pretty(Move move) const { - const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n"; + const string dottedLine = "\n+---+---+---+---+---+---+---+---+"; + const string twoRows = dottedLine + "\n| | . | | . | | . | | . |" + + dottedLine + "\n| . | | . | | . | | . | |"; + + string brd = twoRows + twoRows + twoRows + twoRows + dottedLine; + + std::ostringstream ss; if (move) - { - Position p(*this, this_thread()); - cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move); - } + ss << "\nMove: " << (sideToMove == BLACK ? ".." : "") + << move_to_san(*const_cast(this), move); - for (Rank rank = RANK_8; rank >= RANK_1; rank--) - { - cout << dottedLine << '|'; - for (File file = FILE_A; file <= FILE_H; file++) - { - Square sq = make_square(file, rank); - Piece piece = piece_on(sq); - char c = (color_of(piece) == BLACK ? '=' : ' '); + for (Square sq = SQ_A1; sq <= SQ_H8; sq++) + if (piece_on(sq) != NO_PIECE) + brd[513 - 68*rank_of(sq) + 4*file_of(sq)] = PieceToChar[piece_on(sq)]; - if (piece == NO_PIECE && !opposite_colors(sq, SQ_A1)) - piece++; // Index the dot + ss << brd << "\nFen: " << fen() << "\nKey: " << std::hex << std::uppercase + << std::setfill('0') << std::setw(16) << st->key << "\nCheckers: "; - cout << c << PieceToChar[piece] << c << '|'; - } - } - cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl; + for (Bitboard b = checkers(); b; ) + ss << square_to_string(pop_lsb(&b)) << " "; + + ss << "\nLegal moves: "; + for (MoveList it(*this); *it; ++it) + ss << move_to_san(*const_cast(this), *it) << " "; + + return ss.str(); } @@ -377,9 +433,9 @@ Bitboard Position::hidden_checkers() const { while (pinners) { - b = squares_between(ksq, pop_1st_bit(&pinners)) & pieces(); + b = between_bb(ksq, pop_lsb(&pinners)) & pieces(); - if (b && single_bit(b) && (b & pieces(sideToMove))) + if (b && !more_than_one(b) && (b & pieces(sideToMove))) result |= b; } return result; @@ -395,8 +451,8 @@ template Bitboard Position::hidden_checkers() const; Bitboard Position::attackers_to(Square s, Bitboard occ) const { - return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) - | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) + return (attacks_from(s, BLACK) & pieces(WHITE, PAWN)) + | (attacks_from(s, WHITE) & pieces(BLACK, PAWN)) | (attacks_from(s) & pieces(KNIGHT)) | (attacks_bb(s, occ) & pieces(ROOK, QUEEN)) | (attacks_bb(s, occ) & pieces(BISHOP, QUEEN)) @@ -421,37 +477,6 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { } -/// Position::move_attacks_square() tests whether a move from the current -/// position attacks a given square. - -bool Position::move_attacks_square(Move m, Square s) const { - - assert(is_ok(m)); - assert(is_ok(s)); - - Bitboard occ, xray; - Square from = from_sq(m); - Square to = to_sq(m); - Piece piece = piece_moved(m); - - assert(!square_empty(from)); - - // Update occupancy as if the piece is moving - occ = pieces() ^ from ^ to; - - // The piece moved in 'to' attacks the square 's' ? - if (attacks_from(piece, to, occ) & s) - return true; - - // Scan for possible X-ray attackers behind the moved piece - xray = (attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece))) - |(attacks_bb(s, occ) & pieces(BISHOP, QUEEN, color_of(piece))); - - // Verify attackers are triggered by our move and not already existing - return xray && (xray ^ (xray & attacks_from(s))); -} - - /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { @@ -468,7 +493,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // En passant captures are a tricky special case. Because they are rather // uncommon, we do it simply by testing whether the king is attacked after // the move is made. - if (is_enpassant(m)) + if (type_of(m) == ENPASSANT) { Color them = ~us; Square to = to_sq(m); @@ -481,15 +506,15 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(piece_on(capsq) == make_piece(them, PAWN)); assert(piece_on(to) == NO_PIECE); - return !(attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them)) - && !(attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); + return !(attacks_bb< ROOK>(ksq, b) & pieces(them, QUEEN, ROOK)) + && !(attacks_bb(ksq, b) & pieces(them, QUEEN, BISHOP)); } // If the moving piece is a king, check whether the destination // square is attacked by the opponent. Castling moves are checked // for legality during move generation. if (type_of(piece_on(from)) == KING) - return is_castle(m) || !(attackers_to(to_sq(m)) & pieces(~us)); + return type_of(m) == CASTLE || !(attackers_to(to_sq(m)) & pieces(~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. @@ -499,20 +524,6 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } -/// Position::move_is_legal() takes a random move and tests whether the move -/// is legal. This version is not very fast and should be used only in non -/// time-critical paths. - -bool Position::move_is_legal(const Move m) const { - - for (MoveList ml(*this); !ml.end(); ++ml) - if (ml.move() == m) - return true; - - return false; -} - - /// Position::is_pseudo_legal() takes a random move and tests whether the move /// is pseudo legal. It is used to validate moves from TT that can be corrupted /// due to SMP concurrent access or hash position key aliasing. @@ -520,14 +531,13 @@ bool Position::move_is_legal(const Move m) const { bool Position::is_pseudo_legal(const Move m) const { Color us = sideToMove; - Color them = ~sideToMove; Square from = from_sq(m); Square to = to_sq(m); Piece pc = piece_moved(m); // Use a slower but simpler function for uncommon cases - if (is_special(m)) - return move_is_legal(m); + if (type_of(m) != NORMAL) + return MoveList(*this).contains(m); // Is not a promotion, so promotion piece must be empty if (promotion_type(m) - 2 != NO_PIECE_TYPE) @@ -539,7 +549,7 @@ bool Position::is_pseudo_legal(const Move m) const { return false; // The destination square cannot be occupied by a friendly piece - if (color_of(piece_on(to)) == us) + if (piece_on(to) != NO_PIECE && color_of(piece_on(to)) == us) return false; // Handle the special case of a pawn move @@ -565,7 +575,7 @@ bool Position::is_pseudo_legal(const Move m) const { case DELTA_SE: // Capture. The destination square must be occupied by an enemy // piece (en passant captures was handled earlier). - if (color_of(piece_on(to)) != them) + 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 @@ -576,7 +586,7 @@ bool Position::is_pseudo_legal(const Move m) const { case DELTA_N: case DELTA_S: // Pawn push. The destination square must be empty. - if (!square_empty(to)) + if (!is_empty(to)) return false; break; @@ -584,9 +594,9 @@ bool Position::is_pseudo_legal(const Move m) const { // 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 - || !square_empty(to) - || !square_empty(from + DELTA_N)) + if ( rank_of(to) != RANK_4 + || !is_empty(to) + || !is_empty(from + DELTA_N)) return false; break; @@ -594,9 +604,9 @@ bool Position::is_pseudo_legal(const Move m) const { // 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 - || !square_empty(to) - || !square_empty(from + DELTA_S)) + if ( rank_of(to) != RANK_5 + || !is_empty(to) + || !is_empty(from + DELTA_S)) return false; break; @@ -610,18 +620,16 @@ bool Position::is_pseudo_legal(const Move m) const { // Evasions generator already takes care to avoid some kind of illegal moves // and pl_move_is_legal() relies on this. So we have to take care that the // same kind of moves are filtered out here. - if (in_check()) + if (checkers()) { if (type_of(pc) != KING) { - Bitboard b = checkers(); - Square checksq = pop_1st_bit(&b); - - if (b) // double check ? In this case a king move is required + // Double check? In this case a king move is required + if (more_than_one(checkers())) return false; // Our move must be a blocking evasion or a capture of the checking piece - if (!((squares_between(checksq, king_square(us)) | checkers()) & to)) + if (!((between_bb(lsb(checkers()), king_square(us)) | checkers()) & to)) return false; } // In case of king moves under check we have to remove king so to catch @@ -654,37 +662,36 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { if (ci.dcCandidates && (ci.dcCandidates & from)) { // For pawn and king moves we need to verify also direction - if ( (pt != PAWN && pt != KING) + if ( (pt != PAWN && pt != KING) || !squares_aligned(from, to, king_square(~sideToMove))) return true; } // Can we skip the ugly special cases ? - if (!is_special(m)) + if (type_of(m) == NORMAL) return false; Color us = sideToMove; Square ksq = king_square(~us); - // Promotion with check ? - if (is_promotion(m)) + switch (type_of(m)) + { + case PROMOTION: return attacks_from(Piece(promotion_type(m)), to, pieces() ^ from) & ksq; // 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 (is_enpassant(m)) + case ENPASSANT: { - Square capsq = make_square(file_of(to), rank_of(from)); + Square capsq = file_of(to) | rank_of(from); Bitboard b = (pieces() ^ from ^ capsq) | to; - return (attacks_bb< ROOK>(ksq, b) & pieces( ROOK, QUEEN, us)) - | (attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us)); + return (attacks_bb< ROOK>(ksq, b) & pieces(us, QUEEN, ROOK)) + | (attacks_bb(ksq, b) & pieces(us, QUEEN, BISHOP)); } - - // Castling with check ? - if (is_castle(m)) + case CASTLE: { Square kfrom = from; Square rfrom = to; // 'King captures the rook' notation @@ -694,8 +701,10 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { return attacks_bb(rto, b) & ksq; } - - return false; + default: + assert(false); + return false; + } } @@ -718,48 +727,50 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI Key k = 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 pawnKey, materialKey; - Value npMaterial[2]; - int castleRights, rule50, pliesFromNull; - Score psq_score; - Square epSquare; - }; - - memcpy(&newSt, st, sizeof(ReducedStateInfo)); + // which are going to be recalculated from scratch anyway, then switch our state + // pointer to point to the new, ready to be updated, state. + memcpy(&newSt, st, StateCopySize64 * sizeof(uint64_t)); newSt.previous = st; st = &newSt; // Update side to move - k ^= zobSideToMove; + k ^= Zobrist::side; - // Increment the 50 moves rule draw counter. Resetting it to zero in the - // case of a capture or a pawn move is taken care of later. + // Increment ply counters.In particular rule50 will be later reset it to zero + // in case of a capture or a pawn move. + gamePly++; st->rule50++; st->pliesFromNull++; - if (is_castle(m)) - { - st->key = k; - do_castle_move(m); - return; - } - Color us = sideToMove; Color them = ~us; Square from = from_sq(m); Square to = to_sq(m); Piece piece = piece_on(from); PieceType pt = type_of(piece); - PieceType capture = is_enpassant(m) ? PAWN : type_of(piece_on(to)); + PieceType capture = type_of(m) == ENPASSANT ? PAWN : type_of(piece_on(to)); assert(color_of(piece) == us); - assert(color_of(piece_on(to)) != us); + assert(piece_on(to) == NO_PIECE || color_of(piece_on(to)) == them || type_of(m) == CASTLE); assert(capture != KING); + if (type_of(m) == CASTLE) + { + assert(piece == make_piece(us, KING)); + + bool kingSide = to > from; + Square rfrom = to; // Castle is encoded as "king captures friendly rook" + Square rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); + to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); + capture = NO_PIECE_TYPE; + + do_castle(from, to, rfrom, rto); + + st->psqScore += psq_delta(make_piece(us, ROOK), rfrom, rto); + k ^= Zobrist::psq[us][ROOK][rfrom] ^ Zobrist::psq[us][ROOK][rto]; + } + if (capture) { Square capsq = to; @@ -768,7 +779,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // update non-pawn material. if (capture == PAWN) { - if (is_enpassant(m)) + if (type_of(m) == ENPASSANT) { capsq += pawn_push(them); @@ -781,10 +792,10 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI board[capsq] = NO_PIECE; } - st->pawnKey ^= zobrist[them][PAWN][capsq]; + st->pawnKey ^= Zobrist::psq[them][PAWN][capsq]; } else - st->npMaterial[them] -= PieceValueMidgame[capture]; + st->npMaterial[them] -= PieceValue[MG][capture]; // Remove the captured piece byTypeBB[ALL_PIECES] ^= capsq; @@ -794,7 +805,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Update piece list, move the last piece at index[capsq] position and // shrink the list. // - // WARNING: This is a not revresible operation. When we will reinsert the + // WARNING: This is a not reversible operation. When we will reinsert the // captured piece in undo_move() we will put it at the end of the list and // not in its original place, it means index[] and pieceList[] are not // guaranteed to be invariant to a do_move() + undo_move() sequence. @@ -803,9 +814,10 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI pieceList[them][capture][index[lastSquare]] = lastSquare; pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; - // Update hash keys - k ^= zobrist[them][capture][capsq]; - st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + // Update material hash key and prefetch access to materialTable + k ^= Zobrist::psq[them][capture][capsq]; + st->materialKey ^= Zobrist::psq[them][capture][pieceCount[them][capture]]; + prefetch((char*)thisThread->materialTable[st->materialKey]); // Update incremental scores st->psqScore -= pieceSquareTable[make_piece(them, capture)][capsq]; @@ -815,12 +827,12 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI } // Update hash key - k ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; + k ^= Zobrist::psq[us][pt][from] ^ Zobrist::psq[us][pt][to]; // Reset en passant square if (st->epSquare != SQ_NONE) { - k ^= zobEp[file_of(st->epSquare)]; + k ^= Zobrist::enpassant[file_of(st->epSquare)]; st->epSquare = SQ_NONE; } @@ -828,39 +840,42 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (st->castleRights && (castleRightsMask[from] | castleRightsMask[to])) { int cr = castleRightsMask[from] | castleRightsMask[to]; - k ^= zobCastle[st->castleRights & cr]; + k ^= Zobrist::castle[st->castleRights & cr]; st->castleRights &= ~cr; } - // Prefetch TT access as soon as we know key is updated + // Prefetch TT access as soon as we know the new hash key prefetch((char*)TT.first_entry(k)); - // Move the piece - Bitboard from_to_bb = SquareBB[from] | SquareBB[to]; - byTypeBB[ALL_PIECES] ^= from_to_bb; - byTypeBB[pt] ^= from_to_bb; - byColorBB[us] ^= from_to_bb; - - board[to] = board[from]; - board[from] = NO_PIECE; - - // Update piece lists, index[from] is not updated and becomes stale. This - // works as long as index[] is accessed just by known occupied squares. - index[to] = index[from]; - pieceList[us][pt][index[to]] = to; + // Move the piece. The tricky Chess960 castle is handled earlier + if (type_of(m) != CASTLE) + { + Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[pt] ^= from_to_bb; + byColorBB[us] ^= from_to_bb; + + board[from] = NO_PIECE; + board[to] = piece; + + // Update piece lists, index[from] is not updated and becomes stale. This + // works as long as index[] is accessed just by known occupied squares. + index[to] = index[from]; + pieceList[us][pt][index[to]] = to; + } // If the moving piece is a pawn do some special extra work if (pt == PAWN) { // Set en-passant square, only if moved pawn can be captured if ( (int(to) ^ int(from)) == 16 - && (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them))) + && (attacks_from(from + pawn_push(us), us) & pieces(them, PAWN))) { st->epSquare = Square((from + to) / 2); - k ^= zobEp[file_of(st->epSquare)]; + k ^= Zobrist::enpassant[file_of(st->epSquare)]; } - if (is_promotion(m)) + if (type_of(m) == PROMOTION) { PieceType promotion = promotion_type(m); @@ -882,30 +897,27 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI pieceList[us][promotion][index[to]] = to; // Update hash keys - k ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; - st->pawnKey ^= zobrist[us][PAWN][to]; - st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]++] - ^ zobrist[us][PAWN][pieceCount[us][PAWN]]; + k ^= Zobrist::psq[us][PAWN][to] ^ Zobrist::psq[us][promotion][to]; + st->pawnKey ^= Zobrist::psq[us][PAWN][to]; + st->materialKey ^= Zobrist::psq[us][promotion][pieceCount[us][promotion]++] + ^ Zobrist::psq[us][PAWN][pieceCount[us][PAWN]]; // Update incremental score st->psqScore += pieceSquareTable[make_piece(us, promotion)][to] - pieceSquareTable[make_piece(us, PAWN)][to]; // Update material - st->npMaterial[us] += PieceValueMidgame[promotion]; + st->npMaterial[us] += PieceValue[MG][promotion]; } - // Update pawn hash key - st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + // Update pawn hash key and prefetch access to pawnsTable + st->pawnKey ^= Zobrist::psq[us][PAWN][from] ^ Zobrist::psq[us][PAWN][to]; + prefetch((char*)thisThread->pawnsTable[st->pawnKey]); // Reset rule 50 draw counter st->rule50 = 0; } - // Prefetch pawn and material hash tables - prefetch((char*)Threads[threadID].pawnTable.entries[st->pawnKey]); - prefetch((char*)Threads[threadID].materialTable.entries[st->materialKey]); - // Update incremental scores st->psqScore += psq_delta(piece, from, to); @@ -920,7 +932,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (moveIsCheck) { - if (is_special(m)) + if (type_of(m) != NORMAL) st->checkersBB = attackers_to(king_square(them)) & pieces(us); else { @@ -932,17 +944,15 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (ci.dcCandidates && (ci.dcCandidates & from)) { if (pt != ROOK) - st->checkersBB |= attacks_from(king_square(them)) & pieces(ROOK, QUEEN, us); + st->checkersBB |= attacks_from(king_square(them)) & pieces(us, QUEEN, ROOK); if (pt != BISHOP) - st->checkersBB |= attacks_from(king_square(them)) & pieces(BISHOP, QUEEN, us); + st->checkersBB |= attacks_from(king_square(them)) & pieces(us, QUEEN, BISHOP); } } } - // Finish sideToMove = ~sideToMove; - st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo); assert(pos_is_ok()); } @@ -957,25 +967,17 @@ void Position::undo_move(Move m) { sideToMove = ~sideToMove; - if (is_castle(m)) - { - do_castle_move(m); - return; - } - Color us = sideToMove; Color them = ~us; Square from = from_sq(m); Square to = to_sq(m); - Piece piece = piece_on(to); - PieceType pt = type_of(piece); + PieceType pt = type_of(piece_on(to)); PieceType capture = st->capturedType; - assert(square_empty(from)); - assert(color_of(piece) == us); + assert(is_empty(from) || type_of(m) == CASTLE); assert(capture != KING); - if (is_promotion(m)) + if (type_of(m) == PROMOTION) { PieceType promotion = promotion_type(m); @@ -1000,25 +1002,38 @@ void Position::undo_move(Move m) { pt = PAWN; } - // Put the piece back at the source square - Bitboard from_to_bb = SquareBB[from] | SquareBB[to]; - byTypeBB[ALL_PIECES] ^= from_to_bb; - byTypeBB[pt] ^= from_to_bb; - byColorBB[us] ^= from_to_bb; - - board[from] = board[to]; - board[to] = NO_PIECE; - - // Update piece lists, index[to] is not updated and becomes stale. This - // works as long as index[] is accessed just by known occupied squares. - index[from] = index[to]; - pieceList[us][pt][index[from]] = from; + if (type_of(m) == CASTLE) + { + bool kingSide = to > from; + Square rfrom = to; // Castle is encoded as "king captures friendly rook" + Square rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); + to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); + capture = NO_PIECE_TYPE; + pt = KING; + do_castle(to, from, rto, rfrom); + } + else + { + // Put the piece back at the source square + Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[pt] ^= from_to_bb; + byColorBB[us] ^= from_to_bb; + + board[to] = NO_PIECE; + board[from] = make_piece(us, pt); + + // Update piece lists, index[to] is not updated and becomes stale. This + // works as long as index[] is accessed just by known occupied squares. + index[from] = index[to]; + pieceList[us][pt][index[from]] = from; + } if (capture) { Square capsq = to; - if (is_enpassant(m)) + if (type_of(m) == ENPASSANT) { capsq -= pawn_push(us); @@ -1042,166 +1057,82 @@ void Position::undo_move(Move m) { // Finally point our state pointer back to the previous state st = st->previous; + gamePly--; assert(pos_is_ok()); } -/// Position::do_castle_move() is a private method used to do/undo a castling -/// move. Note that castling moves are encoded as "king captures friendly rook" -/// moves, for instance white short castling in a non-Chess960 game is encoded -/// as e1h1. -template -void Position::do_castle_move(Move m) { +/// Position::do_castle() is a helper used to do/undo a castling move. This +/// is a bit tricky, especially in Chess960. - assert(is_ok(m)); - assert(is_castle(m)); - - Square kto, kfrom, rfrom, rto, kAfter, rAfter; +void Position::do_castle(Square kfrom, Square kto, Square rfrom, Square rto) { Color us = sideToMove; - Square kBefore = from_sq(m); - Square rBefore = to_sq(m); - - // Find after-castle squares for king and rook - if (rBefore > kBefore) // O-O - { - kAfter = relative_square(us, SQ_G1); - rAfter = relative_square(us, SQ_F1); - } - else // O-O-O - { - kAfter = relative_square(us, SQ_C1); - rAfter = relative_square(us, SQ_D1); - } - - kfrom = Do ? kBefore : kAfter; - rfrom = Do ? rBefore : rAfter; - - kto = Do ? kAfter : kBefore; - rto = Do ? rAfter : rBefore; - - assert(piece_on(kfrom) == make_piece(us, KING)); - assert(piece_on(rfrom) == make_piece(us, ROOK)); - - // Remove pieces from source squares - byTypeBB[ALL_PIECES] ^= kfrom; - byTypeBB[KING] ^= kfrom; - byColorBB[us] ^= kfrom; - byTypeBB[ALL_PIECES] ^= rfrom; - byTypeBB[ROOK] ^= rfrom; - byColorBB[us] ^= rfrom; - - // Put pieces on destination squares - byTypeBB[ALL_PIECES] |= kto; - byTypeBB[KING] |= kto; - byColorBB[us] |= kto; - byTypeBB[ALL_PIECES] |= rto; - byTypeBB[ROOK] |= rto; - byColorBB[us] |= rto; - - // Update board - Piece king = make_piece(us, KING); - Piece rook = make_piece(us, ROOK); + Bitboard k_from_to_bb = SquareBB[kfrom] ^ SquareBB[kto]; + Bitboard r_from_to_bb = SquareBB[rfrom] ^ SquareBB[rto]; + byTypeBB[KING] ^= k_from_to_bb; + byTypeBB[ROOK] ^= r_from_to_bb; + byTypeBB[ALL_PIECES] ^= k_from_to_bb ^ r_from_to_bb; + byColorBB[us] ^= k_from_to_bb ^ r_from_to_bb; + + // Could be from == to, so first set NO_PIECE then KING and ROOK board[kfrom] = board[rfrom] = NO_PIECE; - board[kto] = king; - board[rto] = rook; - - // Update piece lists - pieceList[us][KING][index[kfrom]] = kto; - pieceList[us][ROOK][index[rfrom]] = rto; - int tmp = index[rfrom]; // In Chess960 could be kto == rfrom - index[kto] = index[kfrom]; - index[rto] = tmp; + board[kto] = make_piece(us, KING); + board[rto] = make_piece(us, ROOK); + + // Could be kfrom == rto, so use a 'tmp' variable + int tmp = index[kfrom]; + index[rto] = index[rfrom]; + index[kto] = tmp; + pieceList[us][KING][index[kto]] = kto; + pieceList[us][ROOK][index[rto]] = rto; +} - if (Do) - { - // Reset capture field - st->capturedType = NO_PIECE_TYPE; - // Update incremental scores - st->psqScore += psq_delta(king, kfrom, kto); - st->psqScore += psq_delta(rook, rfrom, rto); +/// Position::do(undo)_null_move() is used to do(undo) a "null move": It flips +/// the side to move without executing any move on the board. - // Update hash key - st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; - st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; +void Position::do_null_move(StateInfo& newSt) { - // Clear en passant square - if (st->epSquare != SQ_NONE) - { - st->key ^= zobEp[file_of(st->epSquare)]; - st->epSquare = SQ_NONE; - } + assert(!checkers()); - // Update castling rights - st->key ^= zobCastle[st->castleRights & castleRightsMask[kfrom]]; - st->castleRights &= ~castleRightsMask[kfrom]; + memcpy(&newSt, st, sizeof(StateInfo)); // Fully copy here - // Update checkers BB - st->checkersBB = attackers_to(king_square(~us)) & pieces(us); + newSt.previous = st; + st = &newSt; - // Finish - sideToMove = ~sideToMove; - st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo); + if (st->epSquare != SQ_NONE) + { + st->key ^= Zobrist::enpassant[file_of(st->epSquare)]; + st->epSquare = SQ_NONE; } - else - // Undo: point our state pointer back to the previous state - st = st->previous; - - assert(pos_is_ok()); -} + st->key ^= Zobrist::side; + prefetch((char*)TT.first_entry(st->key)); -/// Position::do_null_move() is used to do/undo a "null move": It flips the side -/// to move and updates the hash key without executing any move on the board. -template -void Position::do_null_move(StateInfo& backupSt) { - - assert(!in_check()); - - // Back up the information necessary to undo the null move to the supplied - // StateInfo object. Note that differently from normal case here backupSt - // is actually used as a backup storage not as the new state. This reduces - // the number of fields to be copied. - StateInfo* src = Do ? st : &backupSt; - StateInfo* dst = Do ? &backupSt : st; - - dst->key = src->key; - dst->epSquare = src->epSquare; - dst->psqScore = src->psqScore; - dst->rule50 = src->rule50; - dst->pliesFromNull = src->pliesFromNull; + st->rule50++; + st->pliesFromNull = 0; sideToMove = ~sideToMove; - if (Do) - { - if (st->epSquare != SQ_NONE) - st->key ^= zobEp[file_of(st->epSquare)]; + assert(pos_is_ok()); +} - st->key ^= zobSideToMove; - prefetch((char*)TT.first_entry(st->key)); +void Position::undo_null_move() { - st->epSquare = SQ_NONE; - st->rule50++; - st->pliesFromNull = 0; - st->psqScore += (sideToMove == WHITE ? Tempo : -Tempo); - } + assert(!checkers()); - assert(pos_is_ok()); + st = st->previous; + sideToMove = ~sideToMove; } -// Explicit template instantiations -template void Position::do_null_move(StateInfo& backupSt); -template void Position::do_null_move(StateInfo& backupSt); - /// Position::see() is a static exchange evaluator: It tries to estimate the -/// material gain or loss resulting from a move. There are three versions of -/// this function: One which takes a destination square as input, one takes a -/// move, and one which takes a 'from' and a 'to' square. The function does -/// not yet understand promotions captures. +/// 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. int Position::see_sign(Move m) const { @@ -1210,56 +1141,54 @@ int Position::see_sign(Move m) const { // 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 (PieceValueMidgame[piece_on(to_sq(m))] >= PieceValueMidgame[piece_moved(m)]) + if (PieceValue[MG][piece_on(to_sq(m))] >= PieceValue[MG][piece_moved(m)]) return 1; return see(m); } -int Position::see(Move m) const { +int Position::see(Move m, int asymmThreshold) const { Square from, to; - Bitboard occ, attackers, stmAttackers, b; + Bitboard occupied, attackers, stmAttackers; int swapList[32], slIndex = 1; - PieceType capturedType, pt; + PieceType captured; Color stm; assert(is_ok(m)); - // As castle moves are implemented as capturing the rook, they have - // SEE == RookValueMidgame most of the times (unless the rook is under - // attack). - if (is_castle(m)) - return 0; - from = from_sq(m); to = to_sq(m); - capturedType = type_of(piece_on(to)); - occ = pieces(); + captured = type_of(piece_on(to)); + occupied = pieces() ^ from; // Handle en passant moves - if (is_enpassant(m)) + if (type_of(m) == ENPASSANT) { Square capQq = to - pawn_push(sideToMove); - assert(!capturedType); + assert(!captured); assert(type_of(piece_on(capQq)) == PAWN); // Remove the captured pawn - occ ^= capQq; - capturedType = PAWN; + occupied ^= capQq; + captured = PAWN; } + else if (type_of(m) == CASTLE) + // Castle moves are implemented as king capturing the rook so cannot be + // handled correctly. Simply return 0 that is always the correct value + // unless the rook is ends up under attack. + return 0; // Find all attackers to the destination square, with the moving piece // removed, but possibly an X-ray attacker added behind it. - occ ^= from; - attackers = attackers_to(to, occ); + attackers = attackers_to(to, occupied); // If the opponent has no attackers we are finished stm = ~color_of(piece_on(from)); stmAttackers = attackers & pieces(stm); if (!stmAttackers) - return PieceValueMidgame[capturedType]; + return PieceValue[MG][captured]; // The destination square is defended, which makes things rather more // difficult to compute. We proceed by building up a "swap list" containing @@ -1267,45 +1196,43 @@ int Position::see(Move m) const { // destination square, where the sides alternately capture, and always // capture with the least valuable piece. After each capture, we look for // new X-ray attacks from behind the capturing piece. - swapList[0] = PieceValueMidgame[capturedType]; - capturedType = type_of(piece_on(from)); + swapList[0] = PieceValue[MG][captured]; + captured = type_of(piece_on(from)); do { - // Locate the least valuable attacker for the side to move. The loop - // below looks like it is potentially infinite, but it isn't. We know - // that the side to move still has at least one attacker left. - for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) - assert(pt < KING); - - // Remove the attacker we just found from the 'occupied' bitboard, - // and scan for new X-ray attacks behind the attacker. - b = stmAttackers & pieces(pt); - occ ^= (b & (~b + 1)); - attackers |= (attacks_bb(to, occ) & pieces(ROOK, QUEEN)) - | (attacks_bb(to, occ) & pieces(BISHOP, QUEEN)); - - attackers &= occ; // Cut out pieces we've already done + assert(slIndex < 32); // Add the new entry to the swap list - assert(slIndex < 32); - swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType]; + swapList[slIndex] = -swapList[slIndex - 1] + PieceValue[MG][captured]; slIndex++; - // Remember the value of the capturing piece, and change the side to - // move before beginning the next iteration. - capturedType = pt; + // Locate and remove from 'occupied' the next least valuable attacker + captured = next_attacker(byTypeBB, to, stmAttackers, occupied, attackers); + + attackers &= occupied; // Remove the just found attacker stm = ~stm; stmAttackers = attackers & pieces(stm); - // Stop before processing a king capture - if (capturedType == KING && stmAttackers) + if (captured == KING) { - assert(slIndex < 32); - swapList[slIndex++] = QueenValueMidgame*10; + // Stop before processing a king capture + if (stmAttackers) + swapList[slIndex++] = QueenValueMg * 16; + break; } + } while (stmAttackers); + // If we are doing asymmetric SEE evaluation and the same side does the first + // and the last capture, he 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; + // 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. while (--slIndex) @@ -1327,9 +1254,6 @@ void Position::clear() { 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++) - board[sq] = NO_PIECE; } @@ -1358,19 +1282,21 @@ void Position::put_piece(Piece p, Square s) { Key Position::compute_key() const { - Key result = zobCastle[st->castleRights]; + Key k = Zobrist::castle[st->castleRights]; - for (Square s = SQ_A1; s <= SQ_H8; s++) - if (!square_empty(s)) - result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s]; + for (Bitboard b = pieces(); b; ) + { + Square s = pop_lsb(&b); + k ^= Zobrist::psq[color_of(piece_on(s))][type_of(piece_on(s))][s]; + } if (ep_square() != SQ_NONE) - result ^= zobEp[file_of(ep_square())]; + k ^= Zobrist::enpassant[file_of(ep_square())]; if (sideToMove == BLACK) - result ^= zobSideToMove; + k ^= Zobrist::side; - return result; + return k; } @@ -1382,16 +1308,15 @@ Key Position::compute_key() const { Key Position::compute_pawn_key() const { - Bitboard b; - Key result = 0; + Key k = 0; - for (Color c = WHITE; c <= BLACK; c++) + for (Bitboard b = pieces(PAWN); b; ) { - b = pieces(PAWN, c); - while (b) - result ^= zobrist[c][PAWN][pop_1st_bit(&b)]; + Square s = pop_lsb(&b); + k ^= Zobrist::psq[color_of(piece_on(s))][PAWN][s]; } - return result; + + return k; } @@ -1403,14 +1328,14 @@ Key Position::compute_pawn_key() const { Key Position::compute_material_key() const { - Key result = 0; + Key k = 0; for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= QUEEN; pt++) - for (int i = 0; i < piece_count(c, pt); i++) - result ^= zobrist[c][pt][i]; + for (int cnt = 0; cnt < piece_count(c, pt); cnt++) + k ^= Zobrist::psq[c][pt][cnt]; - return result; + return k; } @@ -1420,19 +1345,15 @@ Key Position::compute_material_key() const { /// updated by do_move and undo_move when the program is running in debug mode. Score Position::compute_psq_score() const { - Bitboard b; - Score result = SCORE_ZERO; + Score score = SCORE_ZERO; - for (Color c = WHITE; c <= BLACK; c++) - for (PieceType pt = PAWN; pt <= KING; pt++) - { - b = pieces(pt, c); - while (b) - result += pieceSquareTable[make_piece(c, pt)][pop_1st_bit(&b)]; - } + for (Bitboard b = pieces(); b; ) + { + Square s = pop_lsb(&b); + score += pieceSquareTable[piece_on(s)][s]; + } - result += (sideToMove == WHITE ? Tempo / 2 : -Tempo / 2); - return result; + return score; } @@ -1443,148 +1364,88 @@ Score Position::compute_psq_score() const { Value Position::compute_non_pawn_material(Color c) const { - Value result = VALUE_ZERO; + Value value = VALUE_ZERO; for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) - result += piece_count(c, pt) * PieceValueMidgame[pt]; + value += piece_count(c, pt) * PieceValue[MG][pt]; - return result; + return value; } /// 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. -template bool Position::is_draw() const { // Draw by material? if ( !pieces(PAWN) - && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMidgame)) + && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg)) return true; // Draw by the 50 moves rule? - if (st->rule50 > 99 && (!in_check() || MoveList(*this).size())) + if (st->rule50 > 99 && (!checkers() || MoveList(*this).size())) return true; // Draw by repetition? - if (!SkipRepetition) - { - int i = 4, e = std::min(st->rule50, st->pliesFromNull); + int i = 4, e = std::min(st->rule50, st->pliesFromNull); - if (i <= e) - { - StateInfo* stp = st->previous->previous; + if (i <= e) + { + StateInfo* stp = st->previous->previous; - do { - stp = stp->previous->previous; + do { + stp = stp->previous->previous; - if (stp->key == st->key) - return true; + if (stp->key == st->key) + return true; - i +=2; + i += 2; - } while (i <= e); - } + } while (i <= e); } return false; } -// Explicit template instantiations -template bool Position::is_draw() const; -template bool Position::is_draw() const; - - -/// Position::init() is a static member function which initializes at startup -/// the various arrays used to compute hash keys and the piece square tables. -/// The latter is a two-step operation: First, the white halves of the tables -/// are copied from PSQT[] tables. Second, the black halves of the tables are -/// initialized by flipping and changing the sign of the white scores. - -void Position::init() { - - RKISS rk; - - for (Color c = WHITE; c <= BLACK; c++) - for (PieceType pt = PAWN; pt <= KING; pt++) - for (Square s = SQ_A1; s <= SQ_H8; s++) - zobrist[c][pt][s] = rk.rand(); - - for (File f = FILE_A; f <= FILE_H; f++) - zobEp[f] = rk.rand(); - - for (int cr = CASTLES_NONE; cr <= ALL_CASTLES; cr++) - { - Bitboard b = cr; - while (b) - { - Key k = zobCastle[1ULL << pop_1st_bit(&b)]; - zobCastle[cr] ^= k ? k : rk.rand(); - } - } - - zobSideToMove = rk.rand(); - zobExclusion = rk.rand(); - - for (Piece p = W_PAWN; p <= W_KING; p++) - { - Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]); - - for (Square s = SQ_A1; s <= SQ_H8; s++) - { - pieceSquareTable[p][s] = ps + PSQT[p][s]; - pieceSquareTable[p+8][~s] = -pieceSquareTable[p][s]; - } - } -} - /// Position::flip() flips position with the white and black sides reversed. This /// is only useful for debugging especially for finding evaluation symmetry bugs. void Position::flip() { - // Make a copy of current position before to start changing - const Position pos(*this, threadID); + const Position pos(*this); clear(); - threadID = pos.this_thread(); - // Board + sideToMove = ~pos.side_to_move(); + thisThread = pos.this_thread(); + nodes = pos.nodes_searched(); + chess960 = pos.is_chess960(); + gamePly = pos.game_ply(); + for (Square s = SQ_A1; s <= SQ_H8; s++) - if (!pos.square_empty(s)) + if (!pos.is_empty(s)) put_piece(Piece(pos.piece_on(s) ^ 8), ~s); - // Side to move - sideToMove = ~pos.side_to_move(); - - // Castling rights if (pos.can_castle(WHITE_OO)) - set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OO)); + set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, KING_SIDE)); if (pos.can_castle(WHITE_OOO)) - set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OOO)); + set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, QUEEN_SIDE)); if (pos.can_castle(BLACK_OO)) - set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OO)); + set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, KING_SIDE)); if (pos.can_castle(BLACK_OOO)) - set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OOO)); + set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, QUEEN_SIDE)); - // En passant square if (pos.st->epSquare != SQ_NONE) st->epSquare = ~pos.st->epSquare; - // Checkers st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); - // Hash keys st->key = compute_key(); st->pawnKey = compute_pawn_key(); st->materialKey = compute_material_key(); - - // Incremental scores st->psqScore = compute_psq_score(); - - // Material st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); @@ -1597,42 +1458,39 @@ void Position::flip() { bool Position::pos_is_ok(int* failedStep) const { + int dummy, *step = failedStep ? failedStep : &dummy; + // What features of the position should be verified? - const bool debugAll = false; - - const bool debugBitboards = debugAll || false; - const bool debugKingCount = debugAll || false; - const bool debugKingCapture = debugAll || false; - const bool debugCheckerCount = debugAll || false; - const bool debugKey = debugAll || false; - const bool debugMaterialKey = debugAll || false; - const bool debugPawnKey = debugAll || false; - const bool debugIncrementalEval = debugAll || false; - const bool debugNonPawnMaterial = debugAll || false; - const bool debugPieceCounts = debugAll || false; - const bool debugPieceList = debugAll || false; - const bool debugCastleSquares = debugAll || false; - - if (failedStep) *failedStep = 1; - - // Side to move OK? + const bool all = false; + + const bool debugBitboards = all || false; + const bool debugKingCount = all || false; + const bool debugKingCapture = all || false; + const bool debugCheckerCount = all || false; + const bool debugKey = all || false; + const bool debugMaterialKey = all || false; + const bool debugPawnKey = all || false; + const bool debugIncrementalEval = all || false; + const bool debugNonPawnMaterial = all || false; + const bool debugPieceCounts = all || false; + const bool debugPieceList = all || false; + const bool debugCastleSquares = all || false; + + *step = 1; + if (sideToMove != WHITE && sideToMove != BLACK) return false; - // Are the king squares in the position correct? - if (failedStep) (*failedStep)++; - if (piece_on(king_square(WHITE)) != W_KING) + if ((*step)++, piece_on(king_square(WHITE)) != W_KING) return false; - if (failedStep) (*failedStep)++; - if (piece_on(king_square(BLACK)) != B_KING) + if ((*step)++, piece_on(king_square(BLACK)) != B_KING) return false; - // Do both sides have exactly one king? - if (failedStep) (*failedStep)++; - if (debugKingCount) + if ((*step)++, debugKingCount) { - int kingCount[2] = {0, 0}; + int kingCount[COLOR_NB] = {}; + for (Square s = SQ_A1; s <= SQ_H8; s++) if (type_of(piece_on(s)) == KING) kingCount[color_of(piece_on(s))]++; @@ -1641,25 +1499,14 @@ bool Position::pos_is_ok(int* failedStep) const { return false; } - // Can the side to move capture the opponent's king? - if (failedStep) (*failedStep)++; - if (debugKingCapture) - { - Color us = sideToMove; - Color them = ~us; - Square ksq = king_square(them); - if (attackers_to(ksq) & pieces(us)) + if ((*step)++, debugKingCapture) + if (attackers_to(king_square(~sideToMove)) & pieces(sideToMove)) return false; - } - // Is there more than 2 checkers? - if (failedStep) (*failedStep)++; - if (debugCheckerCount && popcount(st->checkersBB) > 2) + if ((*step)++, debugCheckerCount && popcount(st->checkersBB) > 2) return false; - // Bitboards OK? - if (failedStep) (*failedStep)++; - if (debugBitboards) + if ((*step)++, debugBitboards) { // The intersection of the white and black pieces must be empty if (pieces(WHITE) & pieces(BLACK)) @@ -1677,57 +1524,35 @@ bool Position::pos_is_ok(int* failedStep) const { return false; } - // En passant square OK? - if (failedStep) (*failedStep)++; - if (ep_square() != SQ_NONE) - { - // The en passant square must be on rank 6, from the point of view of the - // side to move. - if (relative_rank(sideToMove, ep_square()) != RANK_6) - return false; - } + if ((*step)++, ep_square() != SQ_NONE && relative_rank(sideToMove, ep_square()) != RANK_6) + return false; - // Hash key OK? - if (failedStep) (*failedStep)++; - if (debugKey && st->key != compute_key()) + if ((*step)++, debugKey && st->key != compute_key()) return false; - // Pawn hash key OK? - if (failedStep) (*failedStep)++; - if (debugPawnKey && st->pawnKey != compute_pawn_key()) + if ((*step)++, debugPawnKey && st->pawnKey != compute_pawn_key()) return false; - // Material hash key OK? - if (failedStep) (*failedStep)++; - if (debugMaterialKey && st->materialKey != compute_material_key()) + if ((*step)++, debugMaterialKey && st->materialKey != compute_material_key()) return false; - // Incremental eval OK? - if (failedStep) (*failedStep)++; - if (debugIncrementalEval && st->psqScore != compute_psq_score()) + if ((*step)++, debugIncrementalEval && st->psqScore != compute_psq_score()) return false; - // Non-pawn material OK? - if (failedStep) (*failedStep)++; - if (debugNonPawnMaterial) + if ((*step)++, debugNonPawnMaterial) { - if (st->npMaterial[WHITE] != compute_non_pawn_material(WHITE)) - return false; - - if (st->npMaterial[BLACK] != compute_non_pawn_material(BLACK)) + if ( st->npMaterial[WHITE] != compute_non_pawn_material(WHITE) + || st->npMaterial[BLACK] != compute_non_pawn_material(BLACK)) return false; } - // Piece counts OK? - if (failedStep) (*failedStep)++; - if (debugPieceCounts) + if ((*step)++, debugPieceCounts) for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) - if (pieceCount[c][pt] != popcount(pieces(pt, c))) + if (pieceCount[c][pt] != popcount(pieces(c, pt))) return false; - if (failedStep) (*failedStep)++; - if (debugPieceList) + if ((*step)++, debugPieceList) for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) for (int i = 0; i < pieceCount[c][pt]; i++) @@ -1739,20 +1564,23 @@ bool Position::pos_is_ok(int* failedStep) const { return false; } - if (failedStep) (*failedStep)++; - if (debugCastleSquares) - for (CastleRight f = WHITE_OO; f <= BLACK_OOO; f = CastleRight(f << 1)) - { - if (!can_castle(f)) - continue; + if ((*step)++, debugCastleSquares) + for (Color c = WHITE; c <= BLACK; c++) + for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1)) + { + CastleRight cr = make_castle_right(c, s); - Piece rook = (f & (WHITE_OO | WHITE_OOO) ? W_ROOK : B_ROOK); + if (!can_castle(cr)) + continue; - if ( piece_on(castleRookSquare[f]) != rook - || castleRightsMask[castleRookSquare[f]] != f) - return false; - } + if ((castleRightsMask[king_square(c)] & cr) != cr) + return false; + + if ( piece_on(castleRookSquare[c][s]) != make_piece(c, ROOK) + || castleRightsMask[castleRookSquare[c][s]] != cr) + return false; + } - if (failedStep) *failedStep = 0; + *step = 0; return true; }