X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=2f18427d827f8111d0357416d92525bb4ad7bb72;hp=adeef6ec06d3164762b6c3949da8fb20b683e9aa;hb=bb3427ca85bdb20b4c8af12b63f635d03c5e9146;hpb=fc519ca74a110a0ceea3c710c88da096fa850c65 diff --git a/src/position.cpp b/src/position.cpp index adeef6ec..2f18427d 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -22,6 +22,7 @@ #include #include #include +#include #include "bitcount.h" #include "movegen.h" @@ -30,7 +31,6 @@ #include "rkiss.h" #include "thread.h" #include "tt.h" -#include "ucioption.h" using std::string; using std::cout; @@ -42,34 +42,27 @@ Key Position::zobCastle[16]; Key Position::zobSideToMove; Key Position::zobExclusion; -Score Position::PieceSquareTable[16][64]; +Score Position::pieceSquareTable[16][64]; // Material values arrays, indexed by Piece -const Value Position::PieceValueMidgame[17] = { +const Value PieceValueMidgame[17] = { VALUE_ZERO, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, - RookValueMidgame, QueenValueMidgame, VALUE_ZERO, - VALUE_ZERO, VALUE_ZERO, + RookValueMidgame, QueenValueMidgame, + VALUE_ZERO, VALUE_ZERO, VALUE_ZERO, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, RookValueMidgame, QueenValueMidgame }; -const Value Position::PieceValueEndgame[17] = { +const Value PieceValueEndgame[17] = { VALUE_ZERO, PawnValueEndgame, KnightValueEndgame, BishopValueEndgame, - RookValueEndgame, QueenValueEndgame, VALUE_ZERO, - VALUE_ZERO, VALUE_ZERO, + RookValueEndgame, QueenValueEndgame, + VALUE_ZERO, VALUE_ZERO, VALUE_ZERO, PawnValueEndgame, KnightValueEndgame, BishopValueEndgame, RookValueEndgame, QueenValueEndgame }; -// Material values array used by SEE, indexed by PieceType -const Value Position::seeValues[] = { - VALUE_ZERO, - PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, - RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10 -}; - namespace { @@ -85,18 +78,18 @@ namespace { CheckInfo::CheckInfo(const Position& pos) { - Color us = pos.side_to_move(); - Color them = opposite_color(us); + Color them = flip(pos.side_to_move()); + Square ksq = pos.king_square(them); - ksq = pos.king_square(them); - dcCandidates = pos.discovered_check_candidates(us); + pinned = pos.pinned_pieces(); + dcCandidates = pos.discovered_check_candidates(); - checkSq[PAWN] = pos.attacks_from(ksq, them); + 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; + checkSq[ROOK] = pos.attacks_from(ksq); + checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK]; + checkSq[KING] = EmptyBoardBB; } @@ -104,12 +97,13 @@ CheckInfo::CheckInfo(const Position& pos) { /// 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(const Position& pos, int th) { +void Position::copy(const Position& pos, int th) { memcpy(this, &pos, sizeof(Position)); - detach(); // Always detach() in copy c'tor to avoid surprises threadID = th; nodes = 0; + + assert(pos_is_ok()); } Position::Position(const string& fen, bool isChess960, int th) { @@ -119,121 +113,118 @@ Position::Position(const string& fen, bool isChess960, int 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 -} - - /// 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). -void Position::from_fen(const string& fen, bool isChess960) { +void Position::from_fen(const string& fenStr, bool isChess960) { /* A FEN string defines a particular position using only the ASCII character set. - A FEN string contains six fields. The separator between fields is a space. The fields are: + A FEN string contains six fields separated by a space. The fields are: - 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. + 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 "/" + separates ranks. 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). + 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. + 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. + 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. + 6) Fullmove number. The number of the full move. It starts at 1, and is + incremented after Black's move. */ - char token; - int hmc, fmn; + char col, row, token; size_t p; Square sq = SQ_A8; - std::istringstream ss(fen); + std::istringstream fen(fenStr); clear(); - ss >> std::noskipws; + fen >> std::noskipws; - // 1. Piece placement field - while ((ss >> token) && !isspace(token)) + // 1. Piece placement + while ((fen >> token) && !isspace(token)) { - if ((p = PieceToChar.find(token)) != string::npos) + if (token == '/') + sq -= Square(16); // Jump back of 2 rows + + else if (isdigit(token)) + sq += Square(token - '0'); // Skip the given number of files + + else if ((p = PieceToChar.find(token)) != string::npos) { put_piece(Piece(p), sq); sq++; } - else if (isdigit(token)) - sq += Square(token - '0'); // Skip the given number of files - else if (token == '/') - sq -= SQ_A3; // Jump back of 2 rows - else - goto incorrect_fen; } // 2. Active color - if (!(ss >> token) || (token != 'w' && token != 'b')) - goto incorrect_fen; - + fen >> token; sideToMove = (token == 'w' ? WHITE : BLACK); + fen >> 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)) + { + Square rsq; + Color c = islower(token) ? BLACK : WHITE; + Piece rook = make_piece(c, ROOK); - if (!(ss >> token) || !isspace(token)) - goto incorrect_fen; + token = char(toupper(token)); - // 3. Castling availability - while ((ss >> token) && !isspace(token)) - if (!set_castling_rights(token)) - goto incorrect_fen; + if (token == 'K') + for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; rsq--) {} - // 4. En passant square - char col, row; - if ( ((ss >> col) && (col >= 'a' && col <= 'h')) - && ((ss >> row) && (row == '3' || row == '6'))) - { - st->epSquare = make_square(File(col - 'a') + FILE_A, Rank(row - '1') + RANK_1); + else if (token == 'Q') + for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; rsq++) {} - // Ignore if no capture is possible - Color them = opposite_color(sideToMove); - if (!(attacks_from(st->epSquare, them) & pieces(PAWN, sideToMove))) - st->epSquare = SQ_NONE; + else if (token >= 'A' && token <= 'H') + rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + + else + continue; + + set_castle_right(king_square(c), rsq); } - // 5. Halfmove clock - if (ss >> std::skipws >> hmc) - st->rule50 = hmc; + // 4. En passant square. Ignore if no pawn capture is possible + if ( ((fen >> col) && (col >= 'a' && col <= 'h')) + && ((fen >> row) && (row == '3' || row == '6'))) + { + st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); - // 6. Fullmove number - if (ss >> fmn) - startPosPlyCounter = (fmn - 1) * 2 + int(sideToMove == BLACK); + if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove))) + st->epSquare = SQ_NONE; + } - // 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; - castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; + // 5-6. Halfmove clock and fullmove number + fen >> std::skipws >> st->rule50 >> startPosPly; - chess960 = isChess960; - find_checkers(); + // 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); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -241,68 +232,24 @@ void Position::from_fen(const string& fen, bool isChess960) { st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); - return; + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove)); + chess960 = isChess960; -incorrect_fen: - cout << "Error in FEN string: " << fen << endl; + assert(pos_is_ok()); } -/// 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) - { - set_castle_kingside(c); - initialKRFile = square_file(sq); - break; - } - } - else if (token == 'Q') - { - for (Square sq = sqA; sq <= sqH; sq++) - if (piece_on(sq) == rook) - { - set_castle_queenside(c); - initialQRFile = square_file(sq); - break; - } - } - else if (token >= 'A' && token <= 'H') - { - File rookFile = File(token - 'A') + FILE_A; - if (rookFile < initialKFile) - { - set_castle_queenside(c); - initialQRFile = rookFile; - } - else - { - set_castle_kingside(c); - initialKRFile = rookFile; - } - } - else - return token == '-'; +/// Position::set_castle_right() is an helper function used to set castling +/// rights given the corresponding king and rook starting squares. - return true; +void Position::set_castle_right(Square ksq, Square rsq) { + + int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq)); + + st->castleRights |= f; + castleRightsMask[ksq] ^= f; + castleRightsMask[rsq] ^= f; + castleRookSquare[f] = rsq; } @@ -311,54 +258,59 @@ bool Position::set_castling_rights(char token) { const string Position::to_fen() const { - string fen; + std::ostringstream fen; Square sq; - char emptyCnt; + int emptyCnt; - for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/') + for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - emptyCnt = '0'; + emptyCnt = 0; for (File file = FILE_A; file <= FILE_H; file++) { sq = make_square(file, rank); - if (square_is_occupied(sq)) + if (square_is_empty(sq)) + emptyCnt++; + else { - if (emptyCnt != '0') + if (emptyCnt > 0) { - fen += emptyCnt; - emptyCnt = '0'; + fen << emptyCnt; + emptyCnt = 0; } - fen += PieceToChar[piece_on(sq)]; - } else - emptyCnt++; + fen << PieceToChar[piece_on(sq)]; + } } - if (emptyCnt != '0') - fen += emptyCnt; + if (emptyCnt > 0) + fen << emptyCnt; + + if (rank > RANK_1) + fen << '/'; } - fen += (sideToMove == WHITE ? " w " : " b "); + fen << (sideToMove == WHITE ? " w " : " b "); - if (st->castleRights != CASTLES_NONE) - { - if (can_castle_kingside(WHITE)) - fen += chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K'; + if (can_castle(WHITE_OO)) + fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K'); + + if (can_castle(WHITE_OOO)) + fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q'); + + if (can_castle(BLACK_OO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k'); - if (can_castle_queenside(WHITE)) - fen += chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q'; + if (can_castle(BLACK_OOO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q'); - if (can_castle_kingside(BLACK)) - fen += chess960 ? file_to_char(initialKRFile) : 'k'; + if (st->castleRights == CASTLES_NONE) + fen << '-'; - if (can_castle_queenside(BLACK)) - fen += chess960 ? file_to_char(initialQRFile) : 'q'; - } else - fen += '-'; + fen << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ") + << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2; - fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square())); - return fen; + return fen.str(); } @@ -372,8 +324,7 @@ void Position::print(Move move) const { if (move) { Position p(*this, thread()); - string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : ""); - cout << "\nMove is: " << dd << move_to_san(p, move); + cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move); } for (Rank rank = RANK_8; rank >= RANK_1; rank--) @@ -383,11 +334,11 @@ void Position::print(Move move) const { { Square sq = make_square(file, rank); Piece piece = piece_on(sq); + char c = (color_of(piece) == BLACK ? '=' : ' '); - if (piece == PIECE_NONE && square_color(sq) == DARK) + if (piece == PIECE_NONE && color_of(sq) == DARK) piece = PIECE_NONE_DARK_SQ; - char c = (color_of_piece_on(sq) == BLACK ? '=' : ' '); cout << c << PieceToChar[piece] << c << '|'; } } @@ -396,74 +347,39 @@ void Position::print(Move move) const { /// Position:hidden_checkers<>() returns a bitboard of all pinned (against the -/// king) pieces for the given color and for the given pinner type. Or, when -/// template parameter FindPinned is false, the pieces of the given color -/// candidate for a discovery check against the enemy king. -/// Bitboard checkersBB must be already updated when looking for pinners. - +/// king) pieces for the given color. Or, when template parameter FindPinned is +/// false, the function return the pieces of the given color candidate for a +/// discovery check against the enemy king. template -Bitboard Position::hidden_checkers(Color c) const { - - Bitboard result = EmptyBoardBB; - Bitboard pinners = pieces_of_color(FindPinned ? opposite_color(c) : c); +Bitboard Position::hidden_checkers() const { - // Pinned pieces protect our king, dicovery checks attack - // the enemy king. - Square ksq = king_square(FindPinned ? c : opposite_color(c)); + // Pinned pieces protect our king, dicovery checks attack the enemy king + Bitboard b, result = 0; + Bitboard pinners = pieces(FindPinned ? flip(sideToMove) : sideToMove); + Square ksq = king_square(FindPinned ? sideToMove : flip(sideToMove)); - // 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; + // Pinners are sliders, that give check when candidate pinned is removed + pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) + | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]); while (pinners) { - Square s = pop_1st_bit(&pinners); - Bitboard b = squares_between(s, ksq) & occupied_squares(); - - assert(b); + b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares(); - if ( !(b & (b - 1)) // Only one bit set? - && (b & pieces_of_color(c))) // Is an our piece? + // Only one bit set and is an our piece? + if (b && !(b & (b - 1)) && (b & pieces(sideToMove))) result |= b; } return result; } +// Explicit template instantiations +template Bitboard Position::hidden_checkers() const; +template Bitboard Position::hidden_checkers() const; -/// Position:pinned_pieces() returns a bitboard of all pinned (against the -/// king) pieces for the given color. Note that checkersBB bitboard must -/// be already updated. - -Bitboard Position::pinned_pieces(Color c) const { - - return hidden_checkers(c); -} - - -/// Position:discovered_check_candidates() returns a bitboard containing all -/// pieces for the given side which are candidates for giving a discovered -/// check. Contrary to pinned_pieces() here there is no need of checkersBB -/// to be already updated. - -Bitboard Position::discovered_check_candidates(Color c) const { - - return hidden_checkers(c); -} - -/// Position::attackers_to() computes a bitboard containing all pieces which -/// attacks a given square. - -Bitboard Position::attackers_to(Square s) const { - return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) - | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) - | (attacks_from(s) & pieces(KNIGHT)) - | (attacks_from(s) & pieces(ROOK, QUEEN)) - | (attacks_from(s) & pieces(BISHOP, QUEEN)) - | (attacks_from(s) & pieces(KING)); -} +/// Position::attackers_to() computes a bitboard of all pieces which attack a +/// given square. Slider attacks use occ bitboard as occupancy. Bitboard Position::attackers_to(Square s, Bitboard occ) const { @@ -475,21 +391,9 @@ Bitboard Position::attackers_to(Square s, Bitboard occ) const { | (attacks_from(s) & pieces(KING)); } -/// Position::attacks_from() computes a bitboard of all attacks -/// of a given piece put in a given square. -Bitboard Position::attacks_from(Piece p, Square s) const { - - assert(square_is_ok(s)); - - switch (p) - { - case WB: case BB: return attacks_from(s); - case WR: case BR: return attacks_from(s); - case WQ: case BQ: return attacks_from(s); - default: return StepAttacksBB[p][s]; - } -} +/// Position::attacks_from() computes a bitboard of all attacks of a given piece +/// put in a given square. Slider attacks use occ bitboard as occupancy. Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { @@ -510,40 +414,30 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { bool Position::move_attacks_square(Move m, Square s) const { - assert(move_is_ok(m)); + assert(is_ok(m)); assert(square_is_ok(s)); Bitboard occ, xray; - Square f = move_from(m), t = move_to(m); - - assert(square_is_occupied(f)); + Square from = move_from(m); + Square to = move_to(m); + Piece piece = piece_on(from); - if (bit_is_set(attacks_from(piece_on(f), t), s)) - return true; + assert(!square_is_empty(from)); - // Move the piece and scan for X-ray attacks behind it + // Update occupancy as if the piece is moving occ = occupied_squares(); - do_move_bb(&occ, make_move_bb(f, t)); - xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) - |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))) - & pieces_of_color(color_of_piece_on(f)); + do_move_bb(&occ, make_move_bb(from, to)); - // If we have attacks we need to verify that are caused by our move - // and are not already existent ones. - return xray && (xray ^ (xray & attacks_from(s))); -} - - -/// Position::find_checkers() computes the checkersBB bitboard, which -/// contains a nonzero bit for each checking piece (0, 1 or 2). It -/// currently works by calling Position::attackers_to, which is probably -/// inefficient. Consider rewriting this function to use the last move -/// played, like in non-bitboard versions of Glaurung. + // The piece moved in 'to' attacks the square 's' ? + if (bit_is_set(attacks_from(piece, to, occ), s)) + return true; -void Position::find_checkers() { + // Scan for possible X-ray attackers behind the moved piece + xray = (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece))) + |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN, color_of(piece))); - Color us = side_to_move(); - st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us)); + // Verify attackers are triggered by our move and not already existing + return xray && (xray ^ (xray & attacks_from(s))); } @@ -551,24 +445,23 @@ void Position::find_checkers() { 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_ok(m)); + assert(pinned == pinned_pieces()); Color us = side_to_move(); Square from = move_from(m); - assert(color_of_piece_on(from) == us); + assert(color_of(piece_on(from)) == us); assert(piece_on(king_square(us)) == make_piece(us, KING)); - // 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)) + // 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)) { - Color them = opposite_color(us); + Color them = flip(us); Square to = move_to(m); - Square capsq = make_square(square_file(to), square_rank(from)); + Square capsq = to + pawn_push(them); Square ksq = king_square(us); Bitboard b = occupied_squares(); @@ -588,8 +481,8 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // If the moving piece is a king, check whether the destination // square is attacked by the opponent. Castling moves are checked // for legality during move generation. - if (type_of_piece_on(from) == KING) - return move_is_castle(m) || !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us))); + if (type_of(piece_on(from)) == KING) + return is_castle(m) || !(attackers_to(move_to(m)) & pieces(flip(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. @@ -599,42 +492,35 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } -/// Position::move_is_pl_slow() takes a position and a move and tests whether -/// the move is pseudo legal. This version is not very fast and should be used -/// only in non time-critical paths. - -bool Position::move_is_pl_slow(const Move m) const { - - MoveStack mlist[MAX_MOVES]; - MoveStack *cur, *last; +/// 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. - last = in_check() ? generate(*this, mlist) - : generate(*this, mlist); +bool Position::move_is_legal(const Move m) const { - for (cur = mlist; cur != last; cur++) - if (cur->move == m) + for (MoveList ml(*this); !ml.end(); ++ml) + if (ml.move() == m) return true; return false; } -/// Fast version of Position::move_is_pl() that takes a position a move and a -/// bitboard of pinned pieces as input, and tests whether the move is pseudo legal. +/// 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. -bool Position::move_is_pl(const Move m) const { - - assert(is_ok()); +bool Position::is_pseudo_legal(const Move m) const { Color us = sideToMove; - Color them = opposite_color(sideToMove); + Color them = flip(sideToMove); Square from = move_from(m); Square to = move_to(m); Piece pc = piece_on(from); // Use a slower but simpler function for uncommon cases - if (move_is_special(m)) - return move_is_pl_slow(m); + if (is_special(m)) + return move_is_legal(m); // Is not a promotion, so promotion piece must be empty if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE) @@ -642,15 +528,15 @@ bool Position::move_is_pl(const Move m) const { // If the from square is not occupied by a piece belonging to the side to // move, the move is obviously not legal. - if (pc == PIECE_NONE || color_of_piece(pc) != us) + if (pc == PIECE_NONE || color_of(pc) != us) return false; // The destination square cannot be occupied by a friendly piece - if (color_of_piece_on(to) == us) + if (color_of(piece_on(to)) == us) return false; // Handle the special case of a pawn move - if (type_of_piece(pc) == PAWN) + if (type_of(pc) == PAWN) { // Move direction must be compatible with pawn color int direction = to - from; @@ -659,7 +545,7 @@ bool Position::move_is_pl(const Move m) const { // We have already handled promotion moves, so destination // cannot be on the 8/1th rank. - if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1) + if (rank_of(to) == RANK_8 || rank_of(to) == RANK_1) return false; // Proceed according to the square delta between the origin and @@ -672,11 +558,11 @@ bool Position::move_is_pl(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 (color_of(piece_on(to)) != them) return false; // From and to files must be one file apart, avoids a7h5 - if (abs(square_file(from) - square_file(to)) != 1) + if (abs(file_of(from) - file_of(to)) != 1) return false; break; @@ -691,7 +577,7 @@ bool Position::move_is_pl(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 ( square_rank(to) != RANK_4 + if ( rank_of(to) != RANK_4 || !square_is_empty(to) || !square_is_empty(from + DELTA_N)) return false; @@ -701,7 +587,7 @@ bool Position::move_is_pl(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 ( square_rank(to) != RANK_5 + if ( rank_of(to) != RANK_5 || !square_is_empty(to) || !square_is_empty(from + DELTA_S)) return false; @@ -714,15 +600,18 @@ bool Position::move_is_pl(const Move m) const { else if (!bit_is_set(attacks_from(pc, from), to)) return false; + // Evasions generator already takes care to avoid some kind of illegal moves + // and pl_move_is_legal() relies on this. So we have to take care that the + // same kind of moves are filtered out here. if (in_check()) { // In case of king moves under check we have to remove king so to catch // as invalid moves like b1a1 when opposite queen is on c1. - if (type_of_piece_on(from) == KING) + if (type_of(piece_on(from)) == KING) { Bitboard b = occupied_squares(); clear_bit(&b, from); - if (attackers_to(move_to(m), b) & pieces_of_color(opposite_color(us))) + if (attackers_to(move_to(m), b) & pieces(flip(us))) return false; } else @@ -744,24 +633,17 @@ bool Position::move_is_pl(const Move m) const { } -/// Position::move_gives_check() tests whether a pseudo-legal move is a check - -bool Position::move_gives_check(Move m) const { - - return move_gives_check(m, CheckInfo(*this)); -} +/// Position::move_gives_check() tests whether a pseudo-legal move gives a check bool Position::move_gives_check(Move m, const CheckInfo& ci) const { - assert(is_ok()); - assert(move_is_ok(m)); - 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) == make_piece(opposite_color(side_to_move()), KING)); + assert(is_ok(m)); + assert(ci.dcCandidates == discovered_check_candidates()); + assert(color_of(piece_on(move_from(m))) == side_to_move()); Square from = move_from(m); Square to = move_to(m); - PieceType pt = type_of_piece_on(from); + PieceType pt = type_of(piece_on(from)); // Direct check ? if (bit_is_set(ci.checkSq[pt], to)) @@ -772,53 +654,41 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { { // For pawn and king moves we need to verify also direction if ( (pt != PAWN && pt != KING) - || !squares_aligned(from, to, ci.ksq)) + || !squares_aligned(from, to, king_square(flip(side_to_move())))) return true; } // Can we skip the ugly special cases ? - if (!move_is_special(m)) + if (!is_special(m)) return false; Color us = side_to_move(); Bitboard b = occupied_squares(); + Square ksq = king_square(flip(us)); // Promotion with check ? - if (move_is_promotion(m)) + if (is_promotion(m)) { clear_bit(&b, from); - - switch (promotion_piece_type(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 bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), 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 (move_is_ep(m)) + if (is_enpassant(m)) { - Square capsq = make_square(square_file(to), square_rank(from)); + Square capsq = make_square(file_of(to), rank_of(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)); + return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us)) + ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us)); } // Castling with check ? - if (move_is_castle(m)) + if (is_castle(m)) { Square kfrom, kto, rfrom, rto; kfrom = from; @@ -836,36 +706,13 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { clear_bit(&b, rfrom); set_bit(&b, rto); set_bit(&b, kto); - return bit_is_set(rook_attacks_bb(rto, b), ci.ksq); + return bit_is_set(rook_attacks_bb(rto, b), ksq); } return false; } -/// Position::do_setup_move() makes a permanent move on the board. It should -/// be used when setting up a position on board. You can't undo the move. - -void Position::do_setup_move(Move m) { - - StateInfo newSt; - - do_move(m, newSt); - - // Reset "game ply" in case we made a non-reversible move. - // "game ply" is used for repetition detection. - if (st->rule50 == 0) - st->gamePly = 0; - - // Update the number of plies played from the starting position - startPosPlyCounter++; - - // Our StateInfo newSt is about going out of scope so copy - // its content before it disappears. - detach(); -} - - /// Position::do_move() makes a move, and saves all information necessary /// to a StateInfo object. The move is assumed to be legal. Pseudo-legal /// moves should be filtered out before this function is called. @@ -878,22 +725,21 @@ void Position::do_move(Move m, StateInfo& newSt) { void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) { - assert(is_ok()); - assert(move_is_ok(m)); + assert(is_ok(m)); assert(&newSt != st); nodes++; 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. + // 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; - int castleRights, rule50, gamePly, pliesFromNull; - Square epSquare; - Score value; Value npMaterial[2]; + int castleRights, rule50, pliesFromNull; + Score value; + Square epSquare; }; memcpy(&newSt, st, sizeof(ReducedStateInfo)); @@ -901,10 +747,6 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI newSt.previous = st; st = &newSt; - // Save the current key to the history[] array, in order to be able to - // detect repetition draws. - history[st->gamePly++] = key; - // Update side to move key ^= zobSideToMove; @@ -913,31 +755,78 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->rule50++; st->pliesFromNull++; - if (move_is_castle(m)) + if (is_castle(m)) { st->key = key; - do_castle_move(m); + do_castle_move(m); return; } Color us = side_to_move(); - Color them = opposite_color(us); + Color them = flip(us); Square from = move_from(m); Square to = move_to(m); - bool ep = move_is_ep(m); - bool pm = move_is_promotion(m); - Piece piece = piece_on(from); - PieceType pt = type_of_piece(piece); - PieceType capture = ep ? PAWN : type_of_piece_on(to); + PieceType pt = type_of(piece); + PieceType capture = is_enpassant(m) ? 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 == make_piece(us, PAWN)); - assert(!pm || relative_rank(us, to) == RANK_8); + assert(color_of(piece) == us); + assert(color_of(piece_on(to)) != us); + assert(capture != KING); if (capture) - do_capture_move(key, capture, them, to, ep); + { + Square capsq = to; + + // If the captured piece is a pawn, update pawn hash key, otherwise + // update non-pawn material. + if (capture == PAWN) + { + if (is_enpassant(m)) + { + capsq += pawn_push(them); + + assert(pt == PAWN); + assert(to == st->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(to) == PIECE_NONE); + assert(piece_on(capsq) == make_piece(them, PAWN)); + + board[capsq] = PIECE_NONE; + } + + st->pawnKey ^= zobrist[them][PAWN][capsq]; + } + else + st->npMaterial[them] -= PieceValueMidgame[capture]; + + // Remove the captured piece + clear_bit(&byColorBB[them], capsq); + clear_bit(&byTypeBB[capture], capsq); + clear_bit(&occupied, capsq); + + // 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 + // captured piece in undo_move() we will put it at the end of the list and + // not in its original place, it means index[] and pieceList[] are not + // guaranteed to be invariant to a do_move() + undo_move() sequence. + Square lastSquare = pieceList[them][capture][--pieceCount[them][capture]]; + index[lastSquare] = index[capsq]; + pieceList[them][capture][index[lastSquare]] = lastSquare; + pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; + + // Update hash keys + key ^= zobrist[them][capture][capsq]; + st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + + // Update incremental scores + st->value -= pst(make_piece(them, capture), capsq); + + // Reset rule 50 counter + st->rule50 = 0; + } // Update hash key key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; @@ -963,77 +852,69 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Move the piece Bitboard move_bb = make_move_bb(from, to); - do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[pt]), move_bb); - do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares + do_move_bb(&byColorBB[us], move_bb); + do_move_bb(&byTypeBB[pt], move_bb); + do_move_bb(&occupied, move_bb); board[to] = board[from]; 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 - // by known occupied squares. + // 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 was a pawn do some special extra work + // If the moving piece is a pawn do some special extra work if (pt == PAWN) { - // Reset rule 50 draw counter - st->rule50 = 0; - - // Update pawn hash key and prefetch in L1/L2 cache - st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - - // Set en passant square, only if moved pawn can be captured - if ((to ^ from) == 16) + // Set en-passant square, only if moved pawn can be captured + if ( (to ^ from) == 16 + && (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them))) { - if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) - { - st->epSquare = Square((int(from) + int(to)) / 2); - key ^= zobEp[st->epSquare]; - } + st->epSquare = Square((from + to) / 2); + key ^= zobEp[st->epSquare]; } - if (pm) // promotion ? + if (is_promotion(m)) { PieceType promotion = promotion_piece_type(m); + assert(relative_rank(us, to) == RANK_8); assert(promotion >= KNIGHT && promotion <= QUEEN); - // Insert promoted piece instead of pawn - clear_bit(&(byTypeBB[PAWN]), to); - set_bit(&(byTypeBB[promotion]), to); + // Replace the pawn with the promoted piece + clear_bit(&byTypeBB[PAWN], to); + set_bit(&byTypeBB[promotion], to); board[to] = make_piece(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; + Square lastSquare = pieceList[us][PAWN][--pieceCount[us][PAWN]]; + index[lastSquare] = index[to]; + pieceList[us][PAWN][index[lastSquare]] = lastSquare; pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; - index[to] = pieceCount[us][promotion] - 1; + index[to] = pieceCount[us][promotion]; pieceList[us][promotion][index[to]] = to; - // Partially revert hash keys update + // Update hash keys key ^= 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]]; - // Partially revert and update incremental scores - st->value -= pst(us, PAWN, to); - st->value += pst(us, promotion, to); + // Update incremental score + st->value += pst(make_piece(us, promotion), to) + - pst(make_piece(us, PAWN), to); // Update material st->npMaterial[us] += PieceValueMidgame[promotion]; } + + // Update pawn hash key + st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + + // Reset rule 50 draw counter + st->rule50 = 0; } // Prefetch pawn and material hash tables @@ -1054,8 +935,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (moveIsCheck) { - if (ep | pm) - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); + if (is_special(m)) + st->checkersBB = attackers_to(king_square(them)) & pieces(us); else { // Direct checks @@ -1066,180 +947,19 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) { if (pt != ROOK) - st->checkersBB |= (attacks_from(ci.ksq) & pieces(ROOK, QUEEN, us)); + st->checkersBB |= attacks_from(king_square(them)) & pieces(ROOK, QUEEN, us); if (pt != BISHOP) - st->checkersBB |= (attacks_from(ci.ksq) & pieces(BISHOP, QUEEN, us)); + st->checkersBB |= attacks_from(king_square(them)) & pieces(BISHOP, QUEEN, us); } } } // Finish - sideToMove = opposite_color(sideToMove); - st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); - - assert(is_ok()); -} - - -/// 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(Key& key, PieceType capture, Color them, Square to, bool ep) { - - assert(capture != KING); - - Square capsq = to; - - // If the captured piece was a pawn, update pawn hash key, - // otherwise update non-pawn material. - if (capture == PAWN) - { - 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) == PIECE_NONE); - assert(piece_on(capsq) == make_piece(them, PAWN)); - - board[capsq] = PIECE_NONE; - } - st->pawnKey ^= zobrist[them][PAWN][capsq]; - } - else - st->npMaterial[them] -= PieceValueMidgame[capture]; - - // Remove captured piece - clear_bit(&(byColorBB[them]), capsq); - clear_bit(&(byTypeBB[capture]), capsq); - clear_bit(&(byTypeBB[0]), capsq); - - // Update hash key - key ^= zobrist[them][capture][capsq]; - - // Update incremental scores - 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 - // will reinsert the captured piece in undo_move() we will put it - // at the end of the list and not in its original place, it means - // index[] and pieceList[] are not guaranteed to be invariant to a - // do_move() + undo_move() sequence. - Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]]; - index[lastPieceSquare] = index[capsq]; - pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare; - pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; - - // Reset rule 50 counter - st->rule50 = 0; -} - - -/// Position::do_castle_move() is a private method used to make a castling -/// move. It is called from the main Position::do_move function. 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. - -void Position::do_castle_move(Move m) { - - assert(move_is_ok(m)); - assert(move_is_castle(m)); - - Color us = side_to_move(); - Color them = opposite_color(us); - - // Reset capture field - st->capturedType = PIECE_TYPE_NONE; - - // Find source squares for king and rook - Square kfrom = move_from(m); - Square rfrom = move_to(m); // HACK: See comment at beginning of function - Square kto, rto; - - assert(piece_on(kfrom) == make_piece(us, KING)); - assert(piece_on(rfrom) == make_piece(us, ROOK)); - - // Find destination squares for king and rook - if (rfrom > kfrom) // O-O - { - kto = relative_square(us, SQ_G1); - rto = relative_square(us, SQ_F1); - } else { // O-O-O - kto = relative_square(us, SQ_C1); - rto = relative_square(us, SQ_D1); - } - - // Remove pieces from source squares: - clear_bit(&(byColorBB[us]), kfrom); - clear_bit(&(byTypeBB[KING]), kfrom); - clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares - clear_bit(&(byColorBB[us]), rfrom); - clear_bit(&(byTypeBB[ROOK]), rfrom); - clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares - - // Put pieces on destination squares: - set_bit(&(byColorBB[us]), kto); - set_bit(&(byTypeBB[KING]), kto); - set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares - 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 = make_piece(us, KING); - Piece rook = make_piece(us, ROOK); - board[kfrom] = board[rfrom] = PIECE_NONE; - 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 rto == kfrom - index[kto] = index[kfrom]; - index[rto] = tmp; - - // Update incremental scores - 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]; - st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; - - // Clear en passant square - if (st->epSquare != SQ_NONE) - { - st->key ^= zobEp[st->epSquare]; - st->epSquare = SQ_NONE; - } - - // Update castling rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[kfrom]; - st->key ^= zobCastle[st->castleRights]; - - // Reset rule 50 counter - st->rule50 = 0; - - // Update checkers BB - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); - - // Finish - sideToMove = opposite_color(sideToMove); + sideToMove = flip(sideToMove); st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); - assert(is_ok()); + assert(pos_is_ok()); } @@ -1248,230 +968,253 @@ void Position::do_castle_move(Move m) { void Position::undo_move(Move m) { - assert(is_ok()); - assert(move_is_ok(m)); + assert(is_ok(m)); - sideToMove = opposite_color(sideToMove); + sideToMove = flip(sideToMove); - if (move_is_castle(m)) + if (is_castle(m)) { - undo_castle_move(m); + do_castle_move(m); return; } Color us = side_to_move(); - Color them = opposite_color(us); + Color them = flip(us); Square from = move_from(m); Square to = move_to(m); - bool ep = move_is_ep(m); - bool pm = move_is_promotion(m); - - PieceType pt = type_of_piece_on(to); + Piece piece = piece_on(to); + PieceType pt = type_of(piece); + PieceType capture = st->capturedType; assert(square_is_empty(from)); - assert(color_of_piece_on(to) == us); - assert(!pm || relative_rank(us, to) == RANK_8); - assert(!ep || to == st->previous->epSquare); - assert(!ep || relative_rank(us, to) == RANK_6); - assert(!ep || piece_on(to) == make_piece(us, PAWN)); + assert(color_of(piece) == us); + assert(capture != KING); - if (pm) // promotion ? + if (is_promotion(m)) { PieceType promotion = promotion_piece_type(m); - pt = PAWN; + assert(promotion == pt); + assert(relative_rank(us, to) == RANK_8); assert(promotion >= KNIGHT && promotion <= QUEEN); - assert(piece_on(to) == make_piece(us, promotion)); - // Replace promoted piece with a pawn - clear_bit(&(byTypeBB[promotion]), to); - set_bit(&(byTypeBB[PAWN]), to); + // Replace the promoted piece with the pawn + clear_bit(&byTypeBB[promotion], to); + set_bit(&byTypeBB[PAWN], to); + board[to] = make_piece(us, PAWN); - // Update piece counts - pieceCount[us][promotion]--; - pieceCount[us][PAWN]++; - - // Update piece list replacing promotion piece with a pawn - Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]]; - index[lastPromotionSquare] = index[to]; - pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare; + // Update piece lists, move the last promoted piece at index[to] position + // and shrink the list. Add a new pawn to the list. + Square lastSquare = pieceList[us][promotion][--pieceCount[us][promotion]]; + index[lastSquare] = index[to]; + pieceList[us][promotion][index[lastSquare]] = lastSquare; pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE; - index[to] = pieceCount[us][PAWN] - 1; + index[to] = pieceCount[us][PAWN]++; pieceList[us][PAWN][index[to]] = to; + + pt = PAWN; } // Put the piece back at the source square Bitboard move_bb = make_move_bb(to, from); - do_move_bb(&(byColorBB[us]), move_bb); - do_move_bb(&(byTypeBB[pt]), move_bb); - do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares + do_move_bb(&byColorBB[us], move_bb); + do_move_bb(&byTypeBB[pt], move_bb); + do_move_bb(&occupied, move_bb); - board[from] = make_piece(us, pt); + board[from] = board[to]; board[to] = PIECE_NONE; - // Update piece list + // 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 (st->capturedType) + if (capture) { Square capsq = to; - if (ep) - capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); + if (is_enpassant(m)) + { + capsq -= pawn_push(us); - assert(st->capturedType != KING); - assert(!ep || square_is_empty(capsq)); + assert(pt == PAWN); + assert(to == st->previous->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(capsq) == PIECE_NONE); + } // Restore the captured piece - set_bit(&(byColorBB[them]), capsq); - set_bit(&(byTypeBB[st->capturedType]), capsq); - set_bit(&(byTypeBB[0]), capsq); - - board[capsq] = make_piece(them, st->capturedType); + set_bit(&byColorBB[them], capsq); + set_bit(&byTypeBB[capture], capsq); + set_bit(&occupied, capsq); - // Update piece count - pieceCount[them][st->capturedType]++; + board[capsq] = make_piece(them, capture); // Update piece list, add a new captured piece in capsq square - index[capsq] = pieceCount[them][st->capturedType] - 1; - pieceList[them][st->capturedType][index[capsq]] = capsq; + index[capsq] = pieceCount[them][capture]++; + pieceList[them][capture][index[capsq]] = capsq; } // Finally point our state pointer back to the previous state st = st->previous; - assert(is_ok()); + assert(pos_is_ok()); } -/// Position::undo_castle_move() is a private method used to unmake a castling -/// move. It is called from the main Position::undo_move function. 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. +/// 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) { -void Position::undo_castle_move(Move m) { + assert(is_ok(m)); + assert(is_castle(m)); - assert(move_is_ok(m)); - assert(move_is_castle(m)); + Square kto, kfrom, rfrom, rto, kAfter, rAfter; - // When we have arrived here, some work has already been done by - // Position::undo_move. In particular, the side to move has been switched, - // so the code below is correct. Color us = side_to_move(); + Square kBefore = move_from(m); + Square rBefore = move_to(m); - // Find source squares for king and rook - Square kfrom = move_from(m); - Square rfrom = move_to(m); // HACK: See comment at beginning of function - Square kto, rto; - - // Find destination squares for king and rook - if (rfrom > kfrom) // O-O + // Find after-castle squares for king and rook + if (rBefore > kBefore) // O-O { - kto = relative_square(us, SQ_G1); - rto = relative_square(us, SQ_F1); - } else { // O-O-O - kto = relative_square(us, SQ_C1); - rto = relative_square(us, SQ_D1); + 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(kto) == make_piece(us, KING)); - assert(piece_on(rto) == make_piece(us, ROOK)); - - // Remove pieces from destination squares: - clear_bit(&(byColorBB[us]), kto); - clear_bit(&(byTypeBB[KING]), kto); - clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares - 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); - set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares - set_bit(&(byColorBB[us]), rfrom); - set_bit(&(byTypeBB[ROOK]), rfrom); - set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares + assert(piece_on(kfrom) == make_piece(us, KING)); + assert(piece_on(rfrom) == make_piece(us, ROOK)); + + // Remove pieces from source squares + clear_bit(&byColorBB[us], kfrom); + clear_bit(&byTypeBB[KING], kfrom); + clear_bit(&occupied, kfrom); + clear_bit(&byColorBB[us], rfrom); + clear_bit(&byTypeBB[ROOK], rfrom); + clear_bit(&occupied, rfrom); + + // Put pieces on destination squares + set_bit(&byColorBB[us], kto); + set_bit(&byTypeBB[KING], kto); + set_bit(&occupied, kto); + set_bit(&byColorBB[us], rto); + set_bit(&byTypeBB[ROOK], rto); + set_bit(&occupied, rto); // Update board - board[rto] = board[kto] = PIECE_NONE; - board[rfrom] = make_piece(us, ROOK); - board[kfrom] = make_piece(us, KING); + Piece king = make_piece(us, KING); + Piece rook = make_piece(us, ROOK); + board[kfrom] = board[rfrom] = PIECE_NONE; + board[kto] = king; + board[rto] = rook; // Update piece lists - pieceList[us][KING][index[kto]] = kfrom; - pieceList[us][ROOK][index[rto]] = rfrom; - int tmp = index[rto]; // In Chess960 could be rto == kfrom - index[kfrom] = index[kto]; - index[rfrom] = tmp; + 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; - // Finally point our state pointer back to the previous state - st = st->previous; + if (Do) + { + // Reset capture field + st->capturedType = PIECE_TYPE_NONE; - assert(is_ok()); -} + // Update incremental scores + 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]; + st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; + + // Clear en passant square + if (st->epSquare != SQ_NONE) + { + st->key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; + } + + // Update castling rights + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[kfrom]; + st->key ^= zobCastle[st->castleRights]; + + // Reset rule 50 counter + st->rule50 = 0; + + // Update checkers BB + st->checkersBB = attackers_to(king_square(flip(us))) & pieces(us); + + // Finish + sideToMove = flip(sideToMove); + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); + } + else + // Undo: point our state pointer back to the previous state + st = st->previous; + assert(pos_is_ok()); +} -/// Position::do_null_move makes() a "null move": It switches the side to move -/// and updates the hash key without executing any move on the board. +/// 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(is_ok()); 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 a new state to be used. - backupSt.key = st->key; - backupSt.epSquare = st->epSquare; - 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[st->gamePly++] = st->key; - - // Update the necessary information - if (st->epSquare != SQ_NONE) - st->key ^= zobEp[st->epSquare]; + // 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; - st->key ^= zobSideToMove; - prefetch((char*)TT.first_entry(st->key)); + dst->key = src->key; + dst->epSquare = src->epSquare; + dst->value = src->value; + dst->rule50 = src->rule50; + dst->pliesFromNull = src->pliesFromNull; - sideToMove = opposite_color(sideToMove); - st->epSquare = SQ_NONE; - st->rule50++; - st->pliesFromNull = 0; - st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; -} + sideToMove = flip(sideToMove); + if (Do) + { + if (st->epSquare != SQ_NONE) + st->key ^= zobEp[st->epSquare]; -/// Position::undo_null_move() unmakes a "null move". - -void Position::undo_null_move() { + st->key ^= zobSideToMove; + prefetch((char*)TT.first_entry(st->key)); - assert(is_ok()); - assert(!in_check()); + st->epSquare = SQ_NONE; + st->rule50++; + st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; + } - // Restore information from the our backup StateInfo object - StateInfo* backupSt = st->previous; - st->key = backupSt->key; - st->epSquare = backupSt->epSquare; - st->value = backupSt->value; - st->previous = backupSt->previous; - st->pliesFromNull = backupSt->pliesFromNull; - - // Update the necessary information - sideToMove = opposite_color(sideToMove); - st->rule50--; - st->gamePly--; + assert(pos_is_ok()); } +// 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 @@ -1481,7 +1224,7 @@ void Position::undo_null_move() { int Position::see_sign(Move m) const { - assert(move_is_ok(m)); + assert(is_ok(m)); Square from = move_from(m); Square to = move_to(m); @@ -1489,7 +1232,7 @@ 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 (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from)) + if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)]) return 1; return see(m); @@ -1498,47 +1241,47 @@ int Position::see_sign(Move m) const { int Position::see(Move m) const { Square from, to; - Bitboard occupied, attackers, stmAttackers, b; + Bitboard occ, attackers, stmAttackers, b; int swapList[32], slIndex = 1; PieceType capturedType, pt; Color stm; - assert(move_is_ok(m)); + 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 (move_is_castle(m)) + if (is_castle(m)) return 0; from = move_from(m); to = move_to(m); - capturedType = type_of_piece_on(to); - occupied = occupied_squares(); + capturedType = type_of(piece_on(to)); + occ = occupied_squares(); // Handle en passant moves - if (st->epSquare == to && type_of_piece_on(from) == PAWN) + if (is_enpassant(m)) { - Square capQq = (side_to_move() == WHITE ? to - DELTA_N : to - DELTA_S); + Square capQq = to - pawn_push(side_to_move()); assert(capturedType == PIECE_TYPE_NONE); - assert(type_of_piece_on(capQq) == PAWN); + assert(type_of(piece_on(capQq)) == PAWN); // Remove the captured pawn - clear_bit(&occupied, capQq); + clear_bit(&occ, capQq); capturedType = PAWN; } // Find all attackers to the destination square, with the moving piece // removed, but possibly an X-ray attacker added behind it. - clear_bit(&occupied, from); - attackers = attackers_to(to, occupied); + clear_bit(&occ, from); + attackers = attackers_to(to, occ); // If the opponent has no attackers we are finished - stm = opposite_color(color_of_piece_on(from)); - stmAttackers = attackers & pieces_of_color(stm); + stm = flip(color_of(piece_on(from))); + stmAttackers = attackers & pieces(stm); if (!stmAttackers) - return seeValues[capturedType]; + return PieceValueMidgame[capturedType]; // The destination square is defended, which makes things rather more // difficult to compute. We proceed by building up a "swap list" containing @@ -1546,8 +1289,8 @@ 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] = seeValues[capturedType]; - capturedType = type_of_piece_on(from); + swapList[0] = PieceValueMidgame[capturedType]; + capturedType = type_of(piece_on(from)); do { // Locate the least valuable attacker for the side to move. The loop @@ -1559,22 +1302,22 @@ int Position::see(Move m) const { // Remove the attacker we just found from the 'occupied' bitboard, // and scan for new X-ray attacks behind the attacker. b = stmAttackers & pieces(pt); - occupied ^= (b & (~b + 1)); - attackers |= (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN)) - | (bishop_attacks_bb(to, occupied) & pieces(BISHOP, QUEEN)); + occ ^= (b & (~b + 1)); + attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)); - attackers &= occupied; // Cut out pieces we've already done + attackers &= occ; // Cut out pieces we've already done // Add the new entry to the swap list assert(slIndex < 32); - swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType]; + swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType]; slIndex++; // Remember the value of the capturing piece, and change the side to // move before beginning the next iteration. capturedType = pt; - stm = opposite_color(stm); - stmAttackers = attackers & pieces_of_color(stm); + stm = flip(stm); + stmAttackers = attackers & pieces(stm); // Stop before processing a king capture if (capturedType == KING && stmAttackers) @@ -1588,7 +1331,7 @@ int Position::see(Move m) const { // 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) - swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]); + swapList[slIndex-1] = std::min(-swapList[slIndex], swapList[slIndex-1]); return swapList[0]; } @@ -1602,28 +1345,24 @@ void Position::clear() { st = &startState; memset(st, 0, sizeof(StateInfo)); st->epSquare = SQ_NONE; - startPosPlyCounter = 0; - nodes = 0; memset(byColorBB, 0, sizeof(Bitboard) * 2); memset(byTypeBB, 0, sizeof(Bitboard) * 8); memset(pieceCount, 0, sizeof(int) * 2 * 8); memset(index, 0, sizeof(int) * 64); - for (int i = 0; i < 64; i++) - board[i] = 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++) + { + board[sq] = PIECE_NONE; castleRightsMask[sq] = ALL_CASTLES; - + } sideToMove = WHITE; - initialKFile = FILE_E; - initialKRFile = FILE_H; - initialQRFile = FILE_A; + nodes = 0; + occupied = 0; } @@ -1632,16 +1371,16 @@ void Position::clear() { void Position::put_piece(Piece p, Square s) { - Color c = color_of_piece(p); - PieceType pt = type_of_piece(p); + Color c = color_of(p); + PieceType pt = type_of(p); board[s] = p; index[s] = pieceCount[c][pt]++; pieceList[c][pt][index[s]] = s; - set_bit(&(byTypeBB[pt]), s); - set_bit(&(byColorBB[c]), s); - set_bit(&(byTypeBB[0]), s); // HACK: byTypeBB[0] contains all occupied squares. + set_bit(&byTypeBB[pt], s); + set_bit(&byColorBB[c], s); + set_bit(&occupied, s); } @@ -1655,8 +1394,8 @@ Key Position::compute_key() const { Key result = zobCastle[st->castleRights]; for (Square s = SQ_A1; s <= SQ_H8; s++) - if (square_is_occupied(s)) - result ^= zobrist[color_of_piece_on(s)][type_of_piece_on(s)][s]; + if (!square_is_empty(s)) + result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s]; if (ep_square() != SQ_NONE) result ^= zobEp[ep_square()]; @@ -1697,16 +1436,13 @@ Key Position::compute_pawn_key() const { Key Position::compute_material_key() const { - int count; Key result = 0; for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= QUEEN; pt++) - { - count = piece_count(c, pt); - for (int i = 0; i < count; i++) + for (int i = 0; i < piece_count(c, pt); i++) result ^= zobrist[c][pt][i]; - } + return result; } @@ -1725,7 +1461,7 @@ Score Position::compute_value() const { { b = pieces(pt, c); while (b) - result += pst(c, pt, pop_1st_bit(&b)); + result += pst(make_piece(c, pt), pop_1st_bit(&b)); } result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2); @@ -1766,9 +1502,24 @@ bool Position::is_draw() const { // Draw by repetition? if (!SkipRepetition) - 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; + { + int i = 4, e = std::min(st->rule50, st->pliesFromNull); + + if (i <= e) + { + StateInfo* stp = st->previous->previous; + + do { + stp = stp->previous->previous; + + if (stp->key == st->key) + return true; + + i +=2; + + } while (i <= e); + } + } return false; } @@ -1783,17 +1534,15 @@ template bool Position::is_draw() const; bool Position::is_mate() const { - MoveStack moves[MAX_MOVES]; - return in_check() && generate(*this, moves) == moves; + return in_check() && !MoveList(*this).size(); } -/// 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 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. +/// 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() { @@ -1813,22 +1562,23 @@ void Position::init() { zobSideToMove = rk.rand(); zobExclusion = rk.rand(); - for (Square s = SQ_A1; s <= SQ_H8; s++) - for (Piece p = WP; p <= WK; p++) - PieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]); + for (Piece p = WP; p <= WK; p++) + { + Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]); - for (Square s = SQ_A1; s <= SQ_H8; s++) - for (Piece p = BP; p <= BK; p++) - PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)]; + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + pieceSquareTable[p][s] = ps + PSQT[p][s]; + pieceSquareTable[p+8][flip(s)] = -pieceSquareTable[p][s]; + } + } } -/// Position::flip() flips position with the white and black sides reversed. This +/// Position::flip_me() flips position with the white and black sides reversed. This /// is only useful for debugging especially for finding evaluation symmetry bugs. -void Position::flip() { - - assert(is_ok()); +void Position::flip_me() { // Make a copy of current position before to start changing const Position pos(*this, threadID); @@ -1839,34 +1589,27 @@ void Position::flip() { // Board for (Square s = SQ_A1; s <= SQ_H8; s++) if (!pos.square_is_empty(s)) - put_piece(Piece(pos.piece_on(s) ^ 8), flip_square(s)); + put_piece(Piece(pos.piece_on(s) ^ 8), flip(s)); // Side to move - sideToMove = opposite_color(pos.side_to_move()); + sideToMove = flip(pos.side_to_move()); // Castling rights - if (pos.can_castle_kingside(WHITE)) set_castle_kingside(BLACK); - if (pos.can_castle_queenside(WHITE)) set_castle_queenside(BLACK); - if (pos.can_castle_kingside(BLACK)) set_castle_kingside(WHITE); - if (pos.can_castle_queenside(BLACK)) set_castle_queenside(WHITE); - - initialKFile = pos.initialKFile; - initialKRFile = pos.initialKRFile; - initialQRFile = pos.initialQRFile; - - 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; - castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; + if (pos.can_castle(WHITE_OO)) + set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO))); + if (pos.can_castle(WHITE_OOO)) + set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO))); + if (pos.can_castle(BLACK_OO)) + set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO))); + if (pos.can_castle(BLACK_OOO)) + set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO))); // En passant square if (pos.st->epSquare != SQ_NONE) - st->epSquare = flip_square(pos.st->epSquare); + st->epSquare = flip(pos.st->epSquare); // Checkers - find_checkers(); + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove)); // Hash keys st->key = compute_key(); @@ -1880,14 +1623,14 @@ void Position::flip() { st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); - assert(is_ok()); + assert(pos_is_ok()); } -/// Position::is_ok() performs some consitency checks for the position object. +/// Position::pos_is_ok() performs some consitency checks for the position object. /// This is meant to be helpful when debugging. -bool Position::is_ok(int* failedStep) const { +bool Position::pos_is_ok(int* failedStep) const { // What features of the position should be verified? const bool debugAll = false; @@ -1920,22 +1663,14 @@ bool Position::is_ok(int* failedStep) const { if (piece_on(king_square(BLACK)) != BK) return false; - // Castle files OK? - if (failedStep) (*failedStep)++; - if (!square_is_ok(make_square(initialKRFile, RANK_1))) - return false; - - if (!square_is_ok(make_square(initialQRFile, RANK_1))) - return false; - // Do both sides have exactly one king? if (failedStep) (*failedStep)++; if (debugKingCount) { int kingCount[2] = {0, 0}; for (Square s = SQ_A1; s <= SQ_H8; s++) - if (type_of_piece_on(s) == KING) - kingCount[color_of_piece_on(s)]++; + if (type_of(piece_on(s)) == KING) + kingCount[color_of(piece_on(s))]++; if (kingCount[0] != 1 || kingCount[1] != 1) return false; @@ -1946,9 +1681,9 @@ bool Position::is_ok(int* failedStep) const { if (debugKingCapture) { Color us = side_to_move(); - Color them = opposite_color(us); + Color them = flip(us); Square ksq = king_square(them); - if (attackers_to(ksq) & pieces_of_color(us)) + if (attackers_to(ksq) & pieces(us)) return false; } @@ -1962,12 +1697,12 @@ bool Position::is_ok(int* failedStep) const { if (debugBitboards) { // The intersection of the white and black pieces must be empty - if ((pieces_of_color(WHITE) & pieces_of_color(BLACK)) != EmptyBoardBB) + if ((pieces(WHITE) & pieces(BLACK)) != EmptyBoardBB) return false; // The union of the white and black pieces must be equal to all // occupied squares - if ((pieces_of_color(WHITE) | pieces_of_color(BLACK)) != occupied_squares()) + if ((pieces(WHITE) | pieces(BLACK)) != occupied_squares()) return false; // Separate piece type bitboards must have empty intersections @@ -2032,33 +1767,26 @@ bool Position::is_ok(int* failedStep) const { for (PieceType pt = PAWN; pt <= KING; pt++) for (int i = 0; i < pieceCount[c][pt]; i++) { - if (piece_on(piece_list(c, pt, i)) != make_piece(c, pt)) + if (piece_on(piece_list(c, pt)[i]) != make_piece(c, pt)) return false; - if (index[piece_list(c, pt, i)] != i) + if (index[piece_list(c, pt)[i]] != i) return false; } if (failedStep) (*failedStep)++; if (debugCastleSquares) - { - for (Color c = WHITE; c <= BLACK; c++) + for (CastleRight f = WHITE_OO; f <= BLACK_OOO; f = CastleRight(f << 1)) { - if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != make_piece(c, ROOK)) - return false; + if (!can_castle(f)) + continue; - if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != make_piece(c, ROOK)) + Piece rook = (f & (WHITE_OO | WHITE_OOO) ? WR : BR); + + if ( castleRightsMask[castleRookSquare[f]] != (ALL_CASTLES ^ f) + || piece_on(castleRookSquare[f]) != 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;