X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=18f4978da197241f5ab3d437e56c123cd2c58bbb;hp=d3ca869b8215e20e22e947f95e946f4fdfb53116;hb=ad1f28bc1c1c5426fb8ab246f5d43ad57002b4d5;hpb=22ede4442cd285d7365b9497c3be65fb2c66b4be diff --git a/src/position.cpp b/src/position.cpp index d3ca869b..18f4978d 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -17,107 +17,59 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - -#include #include #include #include -#include #include #include #include "bitcount.h" #include "movegen.h" -#include "movepick.h" #include "position.h" #include "psqtab.h" #include "rkiss.h" -#include "san.h" +#include "thread.h" #include "tt.h" -#include "ucioption.h" using std::string; using std::cout; using std::endl; - -//// -//// Position's static data definitions -//// - Key Position::zobrist[2][8][64]; Key Position::zobEp[64]; 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 { // Bonus for having the side to move (modified by Joona Kiiski) const Score TempoValue = make_score(48, 22); - bool isZero(char c) { return c == '0'; } - - struct PieceLetters : public std::map { - - PieceLetters() { - - operator[]('K') = WK; operator[]('k') = BK; - operator[]('Q') = WQ; operator[]('q') = BQ; - operator[]('R') = WR; operator[]('r') = BR; - operator[]('B') = WB; operator[]('b') = BB; - operator[]('N') = WN; operator[]('n') = BN; - operator[]('P') = WP; operator[]('p') = BP; - operator[](' ') = PIECE_NONE; - operator[]('.') = PIECE_NONE_DARK_SQ; - } - - char from_piece(Piece p) const { - - std::map::const_iterator it; - for (it = begin(); it != end(); ++it) - if (it->second == p) - return it->first; - - assert(false); - return 0; - } - }; - - PieceLetters pieceLetters; + // To convert a Piece to and from a FEN char + const string PieceToChar(".PNBRQK pnbrqk "); } @@ -125,18 +77,18 @@ namespace { CheckInfo::CheckInfo(const Position& pos) { - Color us = pos.side_to_move(); - Color them = opposite_color(us); + Color them = opposite_color(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; } @@ -150,11 +102,13 @@ Position::Position(const Position& pos, int th) { detach(); // Always detach() in copy c'tor to avoid surprises threadID = th; nodes = 0; + + assert(is_ok()); } -Position::Position(const string& fen, int th) { +Position::Position(const string& fen, bool isChess960, int th) { - from_fen(fen); + from_fen(fen, isChess960); threadID = th; } @@ -167,7 +121,7 @@ void Position::detach() { startState = *st; st = &startState; - st->previous = NULL; // as a safe guard + st->previous = NULL; // As a safe guard } @@ -175,14 +129,14 @@ void Position::detach() { /// 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) { +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: 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. + 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 @@ -204,77 +158,56 @@ void Position::from_fen(const string& fen) { 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move. */ - char token; - std::istringstream ss(fen); - Rank rank = RANK_8; - File file = FILE_A; + char col, row, token; + size_t p; + Square sq = SQ_A8; + std::istringstream fen(fenStr); clear(); + fen >> std::noskipws; - // 1. Piece placement field - while (ss.get(token) && token != ' ') + // 1. Piece placement + while ((fen >> token) && !isspace(token)) { - if (isdigit(token)) - { - file += File(token - '0'); // Skip the given number of files - continue; - } - else if (token == '/') - { - file = FILE_A; - rank--; - continue; - } + if (token == '/') + sq -= Square(16); // Jump back of 2 rows - if (pieceLetters.find(token) == pieceLetters.end()) - goto incorrect_fen; + else if (isdigit(token)) + sq += Square(token - '0'); // Skip the given number of files - put_piece(pieceLetters[token], make_square(file, rank)); - file++; + else if ((p = PieceToChar.find(token)) != string::npos) + { + put_piece(Piece(p), sq); + sq++; + } } // 2. Active color - if (!ss.get(token) || (token != 'w' && token != 'b')) - goto incorrect_fen; - + fen >> token; sideToMove = (token == 'w' ? WHITE : BLACK); - - if (!ss.get(token) || token != ' ') - goto incorrect_fen; + fen >> token; // 3. Castling availability - while (ss.get(token) && token != ' ') - { - if (token == '-') - continue; - - if (!set_castling_rights(token)) - goto incorrect_fen; - } + while ((fen >> token) && !isspace(token)) + set_castling_rights(token); - // 4. En passant square -- ignore if no capture is possible - char col, row; - if ( (ss.get(col) && (col >= 'a' && col <= 'h')) - && (ss.get(row) && (row == '3' || row == '6'))) + // 4. En passant square. Ignore if no pawn capture is possible + if ( ((fen >> col) && (col >= 'a' && col <= 'h')) + && ((fen >> row) && (row == '3' || row == '6'))) { - Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row)); + st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); Color them = opposite_color(sideToMove); - if (attacks_from(fenEpSquare, them) & pieces(PAWN, sideToMove)) - st->epSquare = fenEpSquare; + if (!(attacks_from(st->epSquare, them) & pieces(PAWN, sideToMove))) + st->epSquare = SQ_NONE; } - // 5-6. Halfmove clock and fullmove number are not parsed + // 5-6. Halfmove clock and fullmove number + fen >> std::skipws >> st->rule50 >> fullMoves; // 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; - - find_checkers(); + chess960 = isChess960; + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(opposite_color(sideToMove)); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -282,10 +215,20 @@ void Position::from_fen(const string& fen) { st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); - return; -incorrect_fen: - cout << "Error in FEN string: " << fen << endl; + assert(is_ok()); +} + + +/// Position::set_castle() is an helper function used to set +/// correct castling related flags. + +void Position::set_castle(int f, Square ksq, Square rsq) { + + st->castleRights |= f; + castleRightsMask[ksq] ^= f; + castleRightsMask[rsq] ^= f; + castleRookSquare[f] = rsq; } @@ -296,106 +239,93 @@ incorrect_fen: /// 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) { +void 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); + Color c = islower(token) ? BLACK : WHITE; + + Square sqA = relative_square(c, SQ_A1); + Square sqH = relative_square(c, SQ_H1); + Square rsq, ksq = king_square(c); - 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) - { - do_allow_oo(c); - initialKRFile = square_file(sq); - break; - } - } + for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {} + else if (token == 'Q') - { - for (Square sq = sqA; sq <= sqH; sq++) - if (piece_on(sq) == rook) - { - do_allow_ooo(c); - initialQRFile = square_file(sq); - break; - } - } + for (rsq = sqA; piece_on(rsq) != make_piece(c, ROOK); rsq++) {} + else if (token >= 'A' && token <= 'H') - { - File rookFile = File(token - 'A') + FILE_A; - if (rookFile < initialKFile) - { - do_allow_ooo(c); - initialQRFile = rookFile; - } - else - { - do_allow_oo(c); - initialKRFile = rookFile; - } - } - else return false; + rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); - return true; + else return; + + if (square_file(rsq) < square_file(ksq)) + set_castle(WHITE_OOO << c, ksq, rsq); + else + set_castle(WHITE_OO << c, ksq, rsq); } /// Position::to_fen() returns a FEN representation of the position. In case /// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function. -const string Position::to_fen(bool isChess960) const { +const string Position::to_fen() const { - string fen; + std::ostringstream fen; Square sq; - char emptyCnt = '0'; + int emptyCnt; 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); - if (square_is_occupied(sq)) + if (!square_is_empty(sq)) { - fen += emptyCnt; - fen += pieceLetters.from_piece(piece_on(sq)); - emptyCnt = '0'; - } else + if (emptyCnt) + { + fen << emptyCnt; + emptyCnt = 0; + } + fen << PieceToChar[piece_on(sq)]; + } + else emptyCnt++; } - fen += emptyCnt; - fen += '/'; - emptyCnt = '0'; + + if (emptyCnt) + fen << emptyCnt; + + if (rank > RANK_1) + fen << '/'; } - fen.erase(std::remove_if(fen.begin(), fen.end(), isZero), fen.end()); - fen.erase(--fen.end()); - fen += (sideToMove == WHITE ? " w " : " b "); + fen << (sideToMove == WHITE ? " w " : " b "); if (st->castleRights != CASTLES_NONE) { - if (can_castle_kingside(WHITE)) - fen += isChess960 ? char(toupper(file_to_char(initialKRFile))) : 'K'; + if (can_castle(WHITE_OO)) + fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OO))))) : 'K'); - if (can_castle_queenside(WHITE)) - fen += isChess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q'; + if (can_castle(WHITE_OOO)) + fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OOO))))) : 'Q'); - if (can_castle_kingside(BLACK)) - fen += isChess960 ? file_to_char(initialKRFile) : 'k'; + if (can_castle(BLACK_OO)) + fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OO))) : 'k'); - if (can_castle_queenside(BLACK)) - fen += isChess960 ? file_to_char(initialQRFile) : 'q'; + if (can_castle(BLACK_OOO)) + fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OOO))) : 'q'); } else - fen += '-'; + fen << '-'; - fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square())); - return fen; + fen << (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square())) + << " " << st->rule50 << " " << fullMoves; + + return fen.str(); } @@ -405,19 +335,11 @@ const string Position::to_fen(bool isChess960) const { void Position::print(Move move) const { const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n"; - static bool requestPending = false; - - // Check for reentrancy, as example when called from inside - // MovePicker that is used also here in move_to_san() - if (requestPending) - return; - - requestPending = true; if (move) { Position p(*this, thread()); - string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : ""); + string dd = (sideToMove == BLACK ? ".." : ""); cout << "\nMove is: " << dd << move_to_san(p, move); } @@ -427,52 +349,42 @@ void Position::print(Move move) const { for (File file = FILE_A; file <= FILE_H; file++) { Square sq = make_square(file, rank); - char c = (color_of_piece_on(sq) == BLACK ? '=' : ' '); Piece piece = piece_on(sq); if (piece == PIECE_NONE && square_color(sq) == DARK) piece = PIECE_NONE_DARK_SQ; - cout << c << pieceLetters.from_piece(piece) << c << '|'; + char c = (piece_color(piece_on(sq)) == BLACK ? '=' : ' '); + cout << c << PieceToChar[piece] << c << '|'; } } - bool chess960 = (cout.iword(0) != 0); // See set960() - cout << dottedLine << "Fen is: " << to_fen(chess960) << "\nKey is: " << st->key << endl; - requestPending = false; + cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl; } /// 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 Position::hidden_checkers() const { - Bitboard result = EmptyBoardBB; - Bitboard pinners = pieces_of_color(FindPinned ? opposite_color(c) : c); + // Pinned pieces protect our king, dicovery checks attack the enemy king + Bitboard b, result = EmptyBoardBB; + Bitboard pinners = pieces(FindPinned ? opposite_color(sideToMove) : sideToMove); + Square ksq = king_square(FindPinned ? sideToMove : opposite_color(sideToMove)); - // Pinned pieces protect our king, dicovery checks attack - // the enemy king. - Square ksq = king_square(FindPinned ? c : opposite_color(c)); - - // Pinners are sliders, not checkers, that give check when candidate pinned is removed - pinners &= (pieces(ROOK, QUEEN) & 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(); + b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares(); - assert(b); - - 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; @@ -480,23 +392,21 @@ Bitboard Position::hidden_checkers(Color c) 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. +/// king) pieces for the side to move. -Bitboard Position::pinned_pieces(Color c) const { +Bitboard Position::pinned_pieces() const { - return hidden_checkers(c); + return hidden_checkers(); } /// 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. +/// pieces for the side to move which are candidates for giving a discovered +/// check. -Bitboard Position::discovered_check_candidates(Color c) const { +Bitboard Position::discovered_check_candidates() const { - return hidden_checkers(c); + return hidden_checkers(); } /// Position::attackers_to() computes a bitboard containing all pieces which @@ -512,6 +422,16 @@ Bitboard Position::attackers_to(Square s) const { | (attacks_from(s) & pieces(KING)); } +Bitboard Position::attackers_to(Square s, Bitboard occ) const { + + return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) + | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(s) & pieces(KNIGHT)) + | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)) + | (attacks_from(s) & pieces(KING)); +} + /// Position::attacks_from() computes a bitboard of all attacks /// of a given piece put in a given square. @@ -524,7 +444,7 @@ Bitboard Position::attacks_from(Piece p, Square s) const { 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 StepAttackBB[p][s]; + default: return StepAttacksBB[p][s]; } } @@ -537,7 +457,7 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { case WB: case BB: return bishop_attacks_bb(s, occ); case WR: case BR: return rook_attacks_bb(s, occ); case WQ: case BQ: return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ); - default: return StepAttackBB[p][s]; + default: return StepAttacksBB[p][s]; } } @@ -553,7 +473,7 @@ bool Position::move_attacks_square(Move m, Square s) const { Bitboard occ, xray; Square f = move_from(m), t = move_to(m); - assert(square_is_occupied(f)); + assert(!square_is_empty(f)); if (bit_is_set(attacks_from(piece_on(f), t), s)) return true; @@ -563,7 +483,7 @@ bool Position::move_attacks_square(Move m, Square s) const { 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)); + & pieces(piece_color(piece_on(f))); // If we have attacks we need to verify that are caused by our move // and are not already existent ones. @@ -571,47 +491,33 @@ bool Position::move_attacks_square(Move m, Square s) const { } -/// 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. - -void Position::find_checkers() { - - Color us = side_to_move(); - st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us)); -} - - /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal 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(pinned == pinned_pieces()); - // Castling moves are checked for legality during move generation. - if (move_is_castle(m)) - return true; + Color us = side_to_move(); + Square from = move_from(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 + assert(piece_color(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)) { - Color us = side_to_move(); Color them = opposite_color(us); - Square from = move_from(m); 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(); assert(to == ep_square()); - assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); - assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); + assert(piece_on(from) == make_piece(us, PAWN)); + assert(piece_on(capsq) == make_piece(them, PAWN)); assert(piece_on(to) == PIECE_NONE); clear_bit(&b, from); @@ -622,16 +528,11 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); } - Color us = side_to_move(); - Square from = move_from(m); - - assert(color_of_piece_on(from) == us); - assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING)); - // If the moving piece is a king, check whether the destination - // square is attacked by the opponent. - if (type_of_piece_on(from) == KING) - return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us))); + // square is attacked by the opponent. Castling moves are checked + // for legality during move generation. + if (piece_type(piece_on(from)) == KING) + return move_is_castle(m) || !(attackers_to(move_to(m)) & pieces(opposite_color(us))); // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. @@ -641,50 +542,154 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } -/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion +/// Position::move_is_legal() takes a 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::pl_move_is_evasion(Move m, Bitboard pinned) const -{ - assert(is_check()); +bool Position::move_is_legal(const Move m) const { - Color us = side_to_move(); + 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 move and a bitboard +/// of pinned pieces as input, and tests whether the move is pseudo legal. + +bool Position::move_is_pl(const Move m) const { + + Color us = sideToMove; + Color them = opposite_color(sideToMove); Square from = move_from(m); Square to = move_to(m); + Piece pc = piece_on(from); - // King moves and en-passant captures are verified in pl_move_is_legal() - if (type_of_piece_on(from) == KING || move_is_ep(m)) - return pl_move_is_legal(m, pinned); + // Use a slower but simpler function for uncommon cases + if (move_is_special(m)) + return move_is_legal(m); - Bitboard target = checkers(); - Square checksq = pop_1st_bit(&target); + // Is not a promotion, so promotion piece must be empty + if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE) + return false; - if (target) // double check ? + // 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 || piece_color(pc) != us) return false; - // Our move must be a blocking evasion or a capture of the checking piece - target = squares_between(checksq, king_square(us)) | checkers(); - return bit_is_set(target, to) && pl_move_is_legal(m, pinned); -} + // The destination square cannot be occupied by a friendly piece + if (piece_color(piece_on(to)) == us) + return false; + + // Handle the special case of a pawn move + if (piece_type(pc) == PAWN) + { + // Move direction must be compatible with pawn color + int direction = to - from; + if ((us == WHITE) != (direction > 0)) + return false; + // We have already handled promotion moves, so destination + // cannot be on the 8/1th rank. + if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1) + return false; -/// Position::move_is_check() tests whether a pseudo-legal move is a check + // Proceed according to the square delta between the origin and + // destination squares. + switch (direction) + { + case DELTA_NW: + case DELTA_NE: + case DELTA_SW: + case DELTA_SE: + // Capture. The destination square must be occupied by an enemy + // piece (en passant captures was handled earlier). + if (piece_color(piece_on(to)) != them) + return false; -bool Position::move_is_check(Move m) const { + // From and to files must be one file apart, avoids a7h5 + if (abs(square_file(from) - square_file(to)) != 1) + return false; + break; - return move_is_check(m, CheckInfo(*this)); + case DELTA_N: + case DELTA_S: + // Pawn push. The destination square must be empty. + if (!square_is_empty(to)) + return false; + break; + + case DELTA_NN: + // Double white pawn push. The destination square must be on the fourth + // rank, and both the destination square and the square between the + // source and destination squares must be empty. + if ( square_rank(to) != RANK_4 + || !square_is_empty(to) + || !square_is_empty(from + DELTA_N)) + return false; + break; + + case DELTA_SS: + // Double black pawn push. The destination square must be on the fifth + // rank, and both the destination square and the square between the + // source and destination squares must be empty. + if ( square_rank(to) != RANK_5 + || !square_is_empty(to) + || !square_is_empty(from + DELTA_S)) + return false; + break; + + default: + return false; + } + } + else if (!bit_is_set(attacks_from(pc, from), to)) + return false; + + 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 (piece_type(piece_on(from)) == KING) + { + Bitboard b = occupied_squares(); + clear_bit(&b, from); + if (attackers_to(move_to(m), b) & pieces(opposite_color(us))) + return false; + } + else + { + Bitboard target = checkers(); + Square checksq = pop_1st_bit(&target); + + if (target) // double check ? In this case a king move is required + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + target = squares_between(checksq, king_square(us)) | checkers(); + if (!bit_is_set(target, move_to(m))) + return false; + } + } + + return true; } -bool Position::move_is_check(Move m, const CheckInfo& ci) const { - assert(is_ok()); +/// Position::move_gives_check() tests whether a pseudo-legal move is a check + +bool Position::move_gives_check(Move m, const CheckInfo& ci) const { + 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) == piece_of_color_and_type(opposite_color(side_to_move()), KING)); + assert(ci.dcCandidates == discovered_check_candidates()); + assert(piece_color(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 = piece_type(piece_on(from)); // Direct check ? if (bit_is_set(ci.checkSq[pt], to)) @@ -695,7 +700,7 @@ bool Position::move_is_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(opposite_color(side_to_move())))) return true; } @@ -705,22 +710,23 @@ bool Position::move_is_check(Move m, const CheckInfo& ci) const { Color us = side_to_move(); Bitboard b = occupied_squares(); + Square ksq = king_square(opposite_color(us)); // Promotion with check ? if (move_is_promotion(m)) { clear_bit(&b, from); - switch (move_promotion_piece(m)) + switch (promotion_piece_type(m)) { case KNIGHT: - return bit_is_set(attacks_from(to), ci.ksq); + return bit_is_set(attacks_from(to), ksq); case BISHOP: - return bit_is_set(bishop_attacks_bb(to, b), ci.ksq); + return bit_is_set(bishop_attacks_bb(to, b), ksq); case ROOK: - return bit_is_set(rook_attacks_bb(to, b), ci.ksq); + return bit_is_set(rook_attacks_bb(to, b), ksq); case QUEEN: - return bit_is_set(queen_attacks_bb(to, b), ci.ksq); + return bit_is_set(queen_attacks_bb(to, b), ksq); default: assert(false); } @@ -736,8 +742,8 @@ bool Position::move_is_check(Move m, const CheckInfo& ci) const { 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 ? @@ -759,27 +765,53 @@ bool Position::move_is_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; + + // Update the number of full moves after black's move + if (sideToMove == BLACK) + fullMoves++; + + 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; + + // Our StateInfo newSt is about going out of scope so copy + // its content before it disappears. + detach(); + + assert(is_ok()); +} + + /// 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. +/// to a StateInfo object. The move is assumed to be legal. Pseudo-legal +/// moves should be filtered out before this function is called. void Position::do_move(Move m, StateInfo& newSt) { CheckInfo ci(*this); - do_move(m, newSt, ci, move_is_check(m, ci)); + do_move(m, newSt, ci, move_gives_check(m, ci)); } void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) { - assert(is_ok()); assert(move_is_ok(m)); + assert(&newSt != st); nodes++; Key key = st->key; @@ -795,8 +827,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI Value npMaterial[2]; }; - if (&newSt != st) - memcpy(&newSt, st, sizeof(ReducedStateInfo)); + memcpy(&newSt, st, sizeof(ReducedStateInfo)); newSt.previous = st; st = &newSt; @@ -828,12 +859,12 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI 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 = piece_type(piece); + PieceType capture = ep ? PAWN : piece_type(piece_on(to)); - assert(color_of_piece_on(from) == us); - assert(color_of_piece_on(to) == them || square_is_empty(to)); - assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN)); + assert(piece_color(piece_on(from)) == us); + assert(piece_color(piece_on(to)) == them || square_is_empty(to)); + assert(!(ep || pm) || piece == make_piece(us, PAWN)); assert(!pm || relative_rank(us, to) == RANK_8); if (capture) @@ -849,13 +880,12 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->epSquare = SQ_NONE; } - // Update castle rights, try to shortcut a common case - int cm = castleRightsMask[from] & castleRightsMask[to]; - if (cm != ALL_CASTLES && ((cm & st->castleRights) != st->castleRights)) + // Update castle rights if needed + if ( st->castleRights != CASTLES_NONE + && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES) { key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[from]; - st->castleRights &= castleRightsMask[to]; + st->castleRights &= castleRightsMask[from] & castleRightsMask[to]; key ^= zobCastle[st->castleRights]; } @@ -864,9 +894,9 @@ 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(&byTypeBB[0], move_bb); // HACK: byTypeBB[0] == occupied squares board[to] = board[from]; board[from] = PIECE_NONE; @@ -885,12 +915,11 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Update pawn hash key and prefetch in L1/L2 cache st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - prefetchPawn(st->pawnKey, threadID); // Set en passant square, only if moved pawn can be captured if ((to ^ from) == 16) { - if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) + if (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them)) { st->epSquare = Square((int(from) + int(to)) / 2); key ^= zobEp[st->epSquare]; @@ -899,14 +928,14 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (pm) // promotion ? { - PieceType promotion = move_promotion_piece(m); + PieceType promotion = promotion_piece_type(m); assert(promotion >= KNIGHT && promotion <= QUEEN); // Insert promoted piece instead of pawn - clear_bit(&(byTypeBB[PAWN]), to); - set_bit(&(byTypeBB[promotion]), to); - board[to] = piece_of_color_and_type(us, promotion); + clear_bit(&byTypeBB[PAWN], to); + set_bit(&byTypeBB[promotion], to); + board[to] = make_piece(us, promotion); // Update piece counts pieceCount[us][promotion]++; @@ -930,14 +959,18 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->pawnKey ^= zobrist[us][PAWN][to]; // Partially revert and update incremental scores - st->value -= pst(us, PAWN, to); - st->value += pst(us, promotion, to); + st->value -= pst(make_piece(us, PAWN), to); + st->value += pst(make_piece(us, promotion), to); // Update material st->npMaterial[us] += PieceValueMidgame[promotion]; } } + // Prefetch pawn and material hash tables + Threads[threadID].pawnTable.prefetch(st->pawnKey); + Threads[threadID].materialTable.prefetch(st->materialKey); + // Update incremental scores st->value += pst_delta(piece, from, to); @@ -953,7 +986,7 @@ 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); + st->checkersBB = attackers_to(king_square(them)) & pieces(us); else { // Direct checks @@ -964,10 +997,10 @@ 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)); } } } @@ -995,12 +1028,12 @@ void Position::do_capture_move(Key& key, PieceType capture, Color them, Square t { if (ep) // en passant ? { - capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S); + capsq = to + pawn_push(them); assert(to == st->epSquare); assert(relative_rank(opposite_color(them), to) == RANK_6); assert(piece_on(to) == PIECE_NONE); - assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); + assert(piece_on(capsq) == make_piece(them, PAWN)); board[capsq] = PIECE_NONE; } @@ -1010,15 +1043,15 @@ void Position::do_capture_move(Key& key, PieceType capture, Color them, Square t st->npMaterial[them] -= PieceValueMidgame[capture]; // Remove captured piece - clear_bit(&(byColorBB[them]), capsq); - clear_bit(&(byTypeBB[capture]), capsq); - clear_bit(&(byTypeBB[0]), capsq); + 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); + st->value -= pst(make_piece(them, capture), capsq); // Update piece count pieceCount[them][capture]--; @@ -1056,46 +1089,45 @@ void Position::do_castle_move(Move 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 rfrom = move_to(m); Square kto, rto; - assert(piece_on(kfrom) == piece_of_color_and_type(us, KING)); - assert(piece_on(rfrom) == piece_of_color_and_type(us, ROOK)); + 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 + } + 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 = piece_of_color_and_type(us, KING); - Piece rook = piece_of_color_and_type(us, ROOK); + // Remove pieces from source squares + clear_bit(&byColorBB[us], kfrom); + clear_bit(&byTypeBB[KING], kfrom); + clear_bit(&byTypeBB[0], kfrom); + clear_bit(&byColorBB[us], rfrom); + clear_bit(&byTypeBB[ROOK], rfrom); + clear_bit(&byTypeBB[0], rfrom); + + // Put pieces on destination squares + set_bit(&byColorBB[us], kto); + set_bit(&byTypeBB[KING], kto); + set_bit(&byTypeBB[0], kto); + set_bit(&byColorBB[us], rto); + set_bit(&byTypeBB[ROOK], rto); + set_bit(&byTypeBB[0], rto); + + // Update board + Piece king = make_piece(us, KING); + Piece rook = make_piece(us, ROOK); board[kfrom] = board[rfrom] = PIECE_NONE; board[kto] = king; board[rto] = rook; @@ -1103,10 +1135,13 @@ void Position::do_castle_move(Move m) { // 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 + int tmp = index[rfrom]; // In Chess960 could be kto == rfrom index[kto] = index[kfrom]; index[rto] = tmp; + // Reset capture field + st->capturedType = PIECE_TYPE_NONE; + // Update incremental scores st->value += pst_delta(king, kfrom, kto); st->value += pst_delta(rook, rfrom, rto); @@ -1131,7 +1166,7 @@ void Position::do_castle_move(Move m) { st->rule50 = 0; // Update checkers BB - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); + st->checkersBB = attackers_to(king_square(them)) & pieces(us); // Finish sideToMove = opposite_color(sideToMove); @@ -1146,7 +1181,6 @@ void Position::do_castle_move(Move m) { void Position::undo_move(Move m) { - assert(is_ok()); assert(move_is_ok(m)); sideToMove = opposite_color(sideToMove); @@ -1164,26 +1198,26 @@ void Position::undo_move(Move m) { bool ep = move_is_ep(m); bool pm = move_is_promotion(m); - PieceType pt = type_of_piece_on(to); + PieceType pt = piece_type(piece_on(to)); assert(square_is_empty(from)); - assert(color_of_piece_on(to) == us); + assert(piece_color(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) == piece_of_color_and_type(us, PAWN)); + assert(!ep || piece_on(to) == make_piece(us, PAWN)); if (pm) // promotion ? { - PieceType promotion = move_promotion_piece(m); + PieceType promotion = promotion_piece_type(m); pt = PAWN; assert(promotion >= KNIGHT && promotion <= QUEEN); - assert(piece_on(to) == piece_of_color_and_type(us, promotion)); + assert(piece_on(to) == make_piece(us, promotion)); // Replace promoted piece with a pawn - clear_bit(&(byTypeBB[promotion]), to); - set_bit(&(byTypeBB[PAWN]), to); + clear_bit(&byTypeBB[promotion], to); + set_bit(&byTypeBB[PAWN], to); // Update piece counts pieceCount[us][promotion]--; @@ -1200,11 +1234,11 @@ void Position::undo_move(Move m) { // 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(&byTypeBB[0], move_bb); // HACK: byTypeBB[0] == occupied squares - board[from] = piece_of_color_and_type(us, pt); + board[from] = make_piece(us, pt); board[to] = PIECE_NONE; // Update piece list @@ -1216,17 +1250,17 @@ void Position::undo_move(Move m) { Square capsq = to; if (ep) - capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); + capsq = to - pawn_push(us); assert(st->capturedType != KING); assert(!ep || square_is_empty(capsq)); // Restore the captured piece - set_bit(&(byColorBB[them]), capsq); - set_bit(&(byTypeBB[st->capturedType]), capsq); - set_bit(&(byTypeBB[0]), capsq); + set_bit(&byColorBB[them], capsq); + set_bit(&byTypeBB[st->capturedType], capsq); + set_bit(&byTypeBB[0], capsq); - board[capsq] = piece_of_color_and_type(them, st->capturedType); + board[capsq] = make_piece(them, st->capturedType); // Update piece count pieceCount[them][st->capturedType]++; @@ -1254,13 +1288,13 @@ void Position::undo_castle_move(Move m) { assert(move_is_castle(m)); // When we have arrived here, some work has already been done by - // Position::undo_move. In particular, the side to move has been switched, + // Position::undo_move. In particular, the side to move has been switched, // so the code below is correct. Color us = side_to_move(); // 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 rfrom = move_to(m); Square kto, rto; // Find destination squares for king and rook @@ -1268,34 +1302,38 @@ void Position::undo_castle_move(Move m) { { kto = relative_square(us, SQ_G1); rto = relative_square(us, SQ_F1); - } else { // O-O-O + } + else // O-O-O + { kto = relative_square(us, SQ_C1); rto = relative_square(us, SQ_D1); } - assert(piece_on(kto) == piece_of_color_and_type(us, KING)); - assert(piece_on(rto) == piece_of_color_and_type(us, ROOK)); - - // Remove pieces from destination squares: - clear_bit(&(byColorBB[us]), kto); - clear_bit(&(byTypeBB[KING]), kto); - 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(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); + clear_bit(&byColorBB[us], rto); + clear_bit(&byTypeBB[ROOK], rto); + clear_bit(&byTypeBB[0], rto); + + // Put pieces on source squares + set_bit(&byColorBB[us], kfrom); + set_bit(&byTypeBB[KING], kfrom); + set_bit(&byTypeBB[0], kfrom); + set_bit(&byColorBB[us], rfrom); + set_bit(&byTypeBB[ROOK], rfrom); + set_bit(&byTypeBB[0], rfrom); // Update board - board[rto] = board[kto] = PIECE_NONE; - board[rfrom] = piece_of_color_and_type(us, ROOK); - board[kfrom] = piece_of_color_and_type(us, KING); + Piece king = make_piece(us, KING); + Piece rook = make_piece(us, ROOK); + board[kto] = board[rto] = PIECE_NONE; + board[kfrom] = king; + board[rfrom] = rook; // Update piece lists pieceList[us][KING][index[kto]] = kfrom; @@ -1316,8 +1354,7 @@ void Position::undo_castle_move(Move m) { void Position::do_null_move(StateInfo& backupSt) { - assert(is_ok()); - assert(!is_check()); + assert(!in_check()); // Back up the information necessary to undo the null move to the supplied // StateInfo object. @@ -1346,6 +1383,8 @@ void Position::do_null_move(StateInfo& backupSt) { st->rule50++; st->pliesFromNull = 0; st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; + + assert(is_ok()); } @@ -1353,8 +1392,7 @@ void Position::do_null_move(StateInfo& backupSt) { void Position::undo_null_move() { - assert(is_ok()); - assert(!is_check()); + assert(!in_check()); // Restore information from the our backup StateInfo object StateInfo* backupSt = st->previous; @@ -1368,6 +1406,8 @@ void Position::undo_null_move() { sideToMove = opposite_color(sideToMove); st->rule50--; st->gamePly--; + + assert(is_ok()); } @@ -1377,12 +1417,6 @@ void Position::undo_null_move() { /// move, and one which takes a 'from' and a 'to' square. The function does /// not yet understand promotions captures. -int Position::see(Move m) const { - - assert(move_is_ok(m)); - return see(move_from(m), move_to(m)); -} - int Position::see_sign(Move m) const { assert(move_is_ok(m)); @@ -1393,37 +1427,40 @@ 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 (piece_value_midgame(piece_on(to)) >= piece_value_midgame(piece_on(from))) return 1; - return see(from, to); + return see(m); } -int Position::see(Square from, Square to) const { +int Position::see(Move m) const { + Square from, to; Bitboard occupied, attackers, stmAttackers, b; int swapList[32], slIndex = 1; PieceType capturedType, pt; Color stm; - assert(square_is_ok(from)); - assert(square_is_ok(to)); - - capturedType = type_of_piece_on(to); + assert(move_is_ok(m)); - // King cannot be recaptured - if (capturedType == KING) - return seeValues[capturedType]; + // 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)) + return 0; + from = move_from(m); + to = move_to(m); + capturedType = piece_type(piece_on(to)); occupied = occupied_squares(); // Handle en passant moves - if (st->epSquare == to && type_of_piece_on(from) == PAWN) + if (st->epSquare == to && piece_type(piece_on(from)) == PAWN) { - 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(piece_type(piece_on(capQq)) == PAWN); // Remove the captured pawn clear_bit(&occupied, capQq); @@ -1433,18 +1470,13 @@ int Position::see(Square from, Square to) const { // 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 = (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN)) - | (bishop_attacks_bb(to, occupied)& pieces(BISHOP, QUEEN)) - | (attacks_from(to) & pieces(KNIGHT)) - | (attacks_from(to) & pieces(KING)) - | (attacks_from(to, WHITE) & pieces(PAWN, BLACK)) - | (attacks_from(to, BLACK) & pieces(PAWN, WHITE)); + attackers = attackers_to(to, occupied); // If the opponent has no attackers we are finished - stm = opposite_color(color_of_piece_on(from)); - stmAttackers = attackers & pieces_of_color(stm); + stm = opposite_color(piece_color(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 @@ -1452,8 +1484,8 @@ int Position::see(Square from, Square to) 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 = piece_type(piece_on(from)); do { // Locate the least valuable attacker for the side to move. The loop @@ -1473,14 +1505,14 @@ int Position::see(Square from, Square to) const { // 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); + stmAttackers = attackers & pieces(stm); // Stop before processing a king capture if (capturedType == KING && stmAttackers) @@ -1508,62 +1540,42 @@ 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; -} - - -/// Position::reset_game_ply() simply sets gamePly to 0. It is used from the -/// UCI interface code, whenever a non-reversible move is made in a -/// 'position fen moves m1 m2 ...' command. This makes it possible -/// for the program to handle games of arbitrary length, as long as the GUI -/// handles draws by the 50 move rule correctly. - -void Position::reset_game_ply() { - - st->gamePly = 0; + fullMoves = 1; + nodes = 0; } -void Position::inc_startpos_ply_counter() { - - startPosPlyCounter++; -} /// Position::put_piece() puts a piece on the given square of the board, /// updating the board array, pieces list, bitboards, and piece counts. void Position::put_piece(Piece p, Square s) { - Color c = color_of_piece(p); - PieceType pt = type_of_piece(p); + Color c = piece_color(p); + PieceType pt = piece_type(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(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares. } @@ -1577,8 +1589,8 @@ 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[piece_color(piece_on(s))][piece_type(piece_on(s))][s]; if (ep_square() != SQ_NONE) result ^= zobEp[ep_square()]; @@ -1619,16 +1631,13 @@ 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, cnt = piece_count(c, pt); i < cnt; i++) result ^= zobrist[c][pt][i]; - } + return result; } @@ -1647,7 +1656,7 @@ 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); @@ -1674,7 +1683,7 @@ Value Position::compute_non_pawn_material(Color c) const { /// Position::is_draw() tests whether the position is drawn by material, /// repetition, or the 50 moves rule. It does not detect stalemates, this /// must be done by the search. - +template bool Position::is_draw() const { // Draw by material? @@ -1683,118 +1692,74 @@ bool Position::is_draw() const { return true; // Draw by the 50 moves rule? - if (st->rule50 > 99 && (st->rule50 > 100 || !is_mate())) + if (st->rule50 > 99 && !is_mate()) return true; // Draw by repetition? - 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; + 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; return false; } +// Explicit template instantiations +template bool Position::is_draw() const; +template bool Position::is_draw() const; + /// Position::is_mate() returns true or false depending on whether the /// side to move is checkmated. bool Position::is_mate() const { - MoveStack moves[MOVES_MAX]; - return is_check() && generate_moves(*this, moves) == moves; + return in_check() && !MoveList(*this).size(); } -/// Position::has_mate_threat() tests whether the side to move is under -/// a threat of being mated in one from the current position. - -bool Position::has_mate_threat() { - - MoveStack mlist[MOVES_MAX], *last, *cur; - StateInfo st1, st2; - bool mateFound = false; - - // If we are under check it's up to evasions to do the job - if (is_check()) - return false; +/// 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. - // First pass the move to our opponent doing a null move - do_null_move(st1); +void Position::init() { - // Then generate pseudo-legal moves that could give check - last = generate_non_capture_checks(*this, mlist); - last = generate_captures(*this, last); - - // Loop through the moves, and see if one of them gives mate - Bitboard pinned = pinned_pieces(sideToMove); - CheckInfo ci(*this); - for (cur = mlist; cur != last && !mateFound; cur++) - { - Move move = cur->move; - if ( !pl_move_is_legal(move, pinned) - || !move_is_check(move, ci)) - continue; - - do_move(move, st2, ci, true); - - if (is_mate()) - mateFound = true; - - undo_move(move); - } - - undo_null_move(); - return mateFound; -} - - -/// Position::init_zobrist() is a static member function which initializes at -/// startup the various arrays used to compute hash keys. - -void Position::init_zobrist() { - - int i,j, k; RKISS rk; - for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++) - zobrist[i][j][k] = rk.rand(); + 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 (i = 0; i < 64; i++) - zobEp[i] = rk.rand(); + for (Square s = SQ_A1; s <= SQ_H8; s++) + zobEp[s] = rk.rand(); - for (i = 0; i < 16; i++) + for (int i = 0; i < 16; i++) zobCastle[i] = rk.rand(); zobSideToMove = rk.rand(); zobExclusion = rk.rand(); -} - - -/// Position::init_piece_square_tables() initializes the piece square tables. -/// This is a two-step operation: First, the white halves of the tables are -/// copied from the MgPST[][] and EgPST[][] arrays. Second, the black halves -/// of the tables are initialized by mirroring and changing the sign of the -/// corresponding white scores. - -void Position::init_piece_square_tables() { 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]); + pieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]); for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = BP; p <= BK; p++) - PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)]; + pieceSquareTable[p][s] = -pieceSquareTable[p-8][flip_square(s)]; } -/// Position::flipped_copy() makes a copy of the input position, but with -/// the white and black sides reversed. This is only useful for debugging, -/// especially for finding evaluation symmetry bugs. +/// 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::flipped_copy(const Position& pos) { +void Position::flip() { - assert(pos.is_ok()); + // Make a copy of current position before to start changing + const Position pos(*this, threadID); clear(); threadID = pos.thread(); @@ -1808,28 +1773,21 @@ void Position::flipped_copy(const Position& pos) { sideToMove = opposite_color(pos.side_to_move()); // Castling rights - if (pos.can_castle_kingside(WHITE)) do_allow_oo(BLACK); - if (pos.can_castle_queenside(WHITE)) do_allow_ooo(BLACK); - if (pos.can_castle_kingside(BLACK)) do_allow_oo(WHITE); - if (pos.can_castle_queenside(BLACK)) do_allow_ooo(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(BLACK_OO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OO))); + if (pos.can_castle(WHITE_OOO)) + set_castle(BLACK_OOO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OOO))); + if (pos.can_castle(BLACK_OO)) + set_castle(WHITE_OO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OO))); + if (pos.can_castle(BLACK_OOO)) + set_castle(WHITE_OOO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OOO))); // En passant square if (pos.st->epSquare != SQ_NONE) st->epSquare = flip_square(pos.st->epSquare); // Checkers - find_checkers(); + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(opposite_color(sideToMove)); // Hash keys st->key = compute_key(); @@ -1871,7 +1829,7 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) *failedStep = 1; // Side to move OK? - if (!color_is_ok(side_to_move())) + if (side_to_move() != WHITE && side_to_move() != BLACK) return false; // Are the king squares in the position correct? @@ -1883,22 +1841,14 @@ bool Position::is_ok(int* failedStep) const { if (piece_on(king_square(BLACK)) != BK) return false; - // Castle files OK? - if (failedStep) (*failedStep)++; - if (!file_is_ok(initialKRFile)) - return false; - - if (!file_is_ok(initialQRFile)) - 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 (piece_type(piece_on(s)) == KING) + kingCount[piece_color(piece_on(s))]++; if (kingCount[0] != 1 || kingCount[1] != 1) return false; @@ -1911,7 +1861,7 @@ bool Position::is_ok(int* failedStep) const { Color us = side_to_move(); Color them = opposite_color(us); Square ksq = king_square(them); - if (attackers_to(ksq) & pieces_of_color(us)) + if (attackers_to(ksq) & pieces(us)) return false; } @@ -1925,12 +1875,12 @@ 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 @@ -1991,36 +1941,30 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) (*failedStep)++; if (debugPieceList) - { for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) for (int i = 0; i < pieceCount[c][pt]; i++) { - if (piece_on(piece_list(c, pt, i)) != piece_of_color_and_type(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++) { - if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != piece_of_color_and_type(c, ROOK)) - return false; - if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != piece_of_color_and_type(c, ROOK)) + if (debugCastleSquares) + for (CastleRight f = WHITE_OO; f <= BLACK_OOO; f = CastleRight(f << 1)) + { + if (!can_castle(f)) + continue; + + 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;