X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=05e093a8a6fc8b2bae8085d1d7f0eab1806ba324;hp=58884c37f42cb4ee778c9b0a889303b16d6a7b65;hb=f9f30412e798b4ba06375a383a85a9e65bfe299f;hpb=93bc05cf693064b80bf70cb97c6d110ab8f0a015 diff --git a/src/position.cpp b/src/position.cpp index 58884c37..05e093a8 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -23,8 +23,9 @@ //// #include -#include +#include #include +#include #include "mersenne.h" #include "movegen.h" @@ -39,6 +40,8 @@ //// Variables //// +extern SearchStack EmptySearchStack; + int Position::castleRightsMask[64]; Key Position::zobrist[2][8][64]; @@ -50,6 +53,7 @@ Key Position::zobSideToMove; Value Position::MgPieceSquareTable[16][64]; Value Position::EgPieceSquareTable[16][64]; +static bool RequestPending = false; //// //// Functions @@ -57,11 +61,11 @@ Value Position::EgPieceSquareTable[16][64]; /// Constructors -Position::Position(const Position &pos) { +Position::Position(const Position& pos) { copy(pos); } -Position::Position(const std::string &fen) { +Position::Position(const std::string& fen) { from_fen(fen); } @@ -70,7 +74,7 @@ Position::Position(const std::string &fen) { /// string. This function is not very robust - make sure that input FENs are /// correct (this is assumed to be the responsibility of the GUI). -void Position::from_fen(const std::string &fen) { +void Position::from_fen(const std::string& fen) { static const std::string pieceLetters = "KQRBNPkqrbnp"; static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP }; @@ -115,7 +119,7 @@ void Position::from_fen(const std::string &fen) { } sideToMove = (fen[i] == 'w' ? WHITE : BLACK); - // Castling rights: + // Castling rights i++; if (fen[i] != ' ') { @@ -125,8 +129,10 @@ void Position::from_fen(const std::string &fen) { i++; while(strchr("KQkqabcdefghABCDEFGH-", fen[i])) { - if(fen[i] == '-') { - i++; break; + if (fen[i] == '-') + { + i++; + break; } else if(fen[i] == 'K') allow_oo(WHITE); else if(fen[i] == 'Q') allow_ooo(WHITE); @@ -187,7 +193,7 @@ void Position::from_fen(const std::string &fen) { if ( i < fen.length() - 2 && (fen[i] >= 'a' && fen[i] <= 'h') && (fen[i+1] == '3' || fen[i+1] == '6')) - epSquare = square_from_string(fen.substr(i, 2)); + st->epSquare = square_from_string(fen.substr(i, 2)); // Various initialisation for (Square sq = SQ_A1; sq <= SQ_H8; sq++) @@ -201,12 +207,13 @@ void Position::from_fen(const std::string &fen) { castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; find_checkers(); + find_hidden_checks(); - key = compute_key(); - pawnKey = compute_pawn_key(); - materialKey = compute_material_key(); - mgValue = compute_mg_value(); - egValue = compute_eg_value(); + st->key = compute_key(); + st->pawnKey = compute_pawn_key(); + st->materialKey = compute_material_key(); + st->mgValue = compute_value(); + st->egValue = compute_value(); npMaterial[WHITE] = compute_non_pawn_material(WHITE); npMaterial[BLACK] = compute_non_pawn_material(BLACK); } @@ -244,7 +251,7 @@ const std::string Position::to_fen() const { fen += (rank > RANK_1 ? '/' : ' '); } fen += (sideToMove == WHITE ? "w " : "b "); - if (castleRights != NO_CASTLES) + if (st->castleRights != NO_CASTLES) { if (can_castle_kingside(WHITE)) fen += 'K'; if (can_castle_queenside(WHITE)) fen += 'Q'; @@ -270,12 +277,18 @@ void Position::print(Move m) const { static const std::string pieceLetters = " PNBRQK PNBRQK ."; + // Check for reentrancy, as example when called from inside + // MovePicker that is used also here in move_to_san() + if (RequestPending) + return; + + RequestPending = true; + std::cout << std::endl; if (m != MOVE_NONE) { - Position p(*this); std::string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : ""); - std::cout << "Move is: " << col << move_to_san(p, m) << std::endl; + std::cout << "Move is: " << col << move_to_san(*this, m) << std::endl; } for (Rank rank = RANK_8; rank >= RANK_1; rank--) { @@ -294,7 +307,9 @@ void Position::print(Move m) const { } std::cout << "+---+---+---+---+---+---+---+---+" << std::endl << "Fen is: " << to_fen() << std::endl - << "Key is: " << key << std::endl; + << "Key is: " << st->key << std::endl; + + RequestPending = false; } @@ -306,33 +321,13 @@ void Position::copy(const Position &pos) { } -/// Position:pinned_pieces() returns a bitboard of all pinned (against the -/// king) pieces for the given color. -Bitboard Position::pinned_pieces(Color c) const { - - Square ksq = king_square(c); - return hidden_checks(c, ksq) | hidden_checks(c, ksq); -} - - -/// Position:discovered_check_candidates() returns a bitboard containing all -/// pieces for the given side which are candidates for giving a discovered -/// check. The code is almost the same as the function for finding pinned -/// pieces. - -Bitboard Position::discovered_check_candidates(Color c) const { - - Square ksq = king_square(opposite_color(c)); - return hidden_checks(c, ksq) | hidden_checks(c, ksq); -} - - /// Position:hidden_checks<>() 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 pinned pieces of opposite color /// that are, indeed, the pieces candidate for a discovery check. +/// Note that checkersBB bitboard must be already updated. template -Bitboard Position::hidden_checks(Color c, Square ksq) const { +Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const { Square s; Bitboard sliders, result = EmptyBoardBB; @@ -342,14 +337,14 @@ Bitboard Position::hidden_checks(Color c, Square ksq) const { else sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]; - if (sliders && (!FindPinned || (sliders & ~checkersBB))) + if (sliders && (!FindPinned || (sliders & ~st->checkersBB))) { // King blockers are candidate pinned pieces Bitboard candidate_pinned = piece_attacks(ksq) & pieces_of_color(c); // Pinners are sliders, not checkers, that give check when // candidate pinned are removed. - Bitboard pinners = (FindPinned ? sliders & ~checkersBB : sliders); + pinners = (FindPinned ? sliders & ~st->checkersBB : sliders); if (Piece == ROOK) pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); @@ -358,26 +353,17 @@ Bitboard Position::hidden_checks(Color c, Square ksq) const { // Finally for each pinner find the corresponding pinned piece (if same color of king) // or discovery checker (if opposite color) among the candidates. - while (pinners) + Bitboard p = pinners; + while (p) { - s = pop_1st_bit(&pinners); + s = pop_1st_bit(&p); result |= (squares_between(s, ksq) & candidate_pinned); } } - return result; -} - - -/// Position::square_is_attacked() checks whether the given side attacks the -/// given square. - -bool Position::square_is_attacked(Square s, Color c) const { + else + pinners = EmptyBoardBB; - return (pawn_attacks(opposite_color(c), s) & pawns(c)) - || (piece_attacks(s) & knights(c)) - || (piece_attacks(s) & kings(c)) - || (piece_attacks(s) & rooks_and_queens(c)) - || (piece_attacks(s) & bishops_and_queens(c)); + return result; } @@ -396,21 +382,15 @@ Bitboard Position::attacks_to(Square s) const { | (piece_attacks(s) & pieces_of_type(KING)); } -Bitboard Position::attacks_to(Square s, Color c) const { - - return attacks_to(s) & pieces_of_color(c); -} - - /// Position::piece_attacks_square() tests whether the piece on square f /// attacks square t. -bool Position::piece_attacks_square(Square f, Square t) const { +bool Position::piece_attacks_square(Piece p, Square f, Square t) const { assert(square_is_ok(f)); assert(square_is_ok(t)); - switch (piece_on(f)) + switch (p) { case WP: return pawn_attacks_square(WHITE, f, t); case BP: return pawn_attacks_square(BLACK, f, t); @@ -426,8 +406,7 @@ bool Position::piece_attacks_square(Square f, Square t) const { /// Position::move_attacks_square() tests whether a move from the current -/// position attacks a given square. Only attacks by the moving piece are -/// considered; the function does not handle X-ray attacks. +/// position attacks a given square. bool Position::move_attacks_square(Move m, Square s) const { @@ -438,23 +417,25 @@ bool Position::move_attacks_square(Move m, Square s) const { assert(square_is_occupied(f)); - switch (piece_on(f)) - { - case WP: return pawn_attacks_square(WHITE, t, s); - case BP: return pawn_attacks_square(BLACK, t, s); - case WN: case BN: return piece_attacks_square(t, s); - case WB: case BB: return piece_attacks_square(t, s); - case WR: case BR: return piece_attacks_square(t, s); - case WQ: case BQ: return piece_attacks_square(t, s); - case WK: case BK: return piece_attacks_square(t, s); - default: break; - } - return false; + if (piece_attacks_square(piece_on(f), t, s)) + return true; + + // Move the piece and scan for X-ray attacks behind it + Bitboard occ = occupied_squares(); + Color us = color_of_piece_on(f); + clear_bit(&occ, f); + set_bit(&occ, t); + Bitboard xray = ( (rook_attacks_bb(s, occ) & rooks_and_queens()) + |(bishop_attacks_bb(s, occ) & bishops_and_queens())) & pieces_of_color(us); + + // If we have attacks we need to verify that are caused by our move + // and are not already existent ones. + return xray && (xray ^ (xray & piece_attacks(s))); } /// Position::find_checkers() computes the checkersBB bitboard, which -/// contains a nonzero bit for each checking piece (0, 1 or 2). It +/// contains a nonzero bit for each checking piece (0, 1 or 2). It /// currently works by calling Position::attacks_to, which is probably /// inefficient. Consider rewriting this function to use the last move /// played, like in non-bitboard versions of Glaurung. @@ -462,26 +443,37 @@ bool Position::move_attacks_square(Move m, Square s) const { void Position::find_checkers() { Color us = side_to_move(); - checkersBB = attacks_to(king_square(us), opposite_color(us)); + st->checkersBB = attacks_to(king_square(us), opposite_color(us)); } +/// Position:find_hidden_checks() computes the pinned, pinners and dcCandidates +/// bitboards. There are two versions of this function. One takes a color and +/// computes bitboards relative to that color only, the other computes both +/// colors. Bitboard checkersBB must be already updated. + +void Position::find_hidden_checks(Color us) { -/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal. -/// There are two versions of this function: One which takes only a -/// move as input, and one which takes a move and a bitboard of pinned -/// pieces. The latter function is faster, and should always be preferred -/// when a pinned piece bitboard has already been computed. + Bitboard p1, p2; + Color them = opposite_color(us); + Square ksq = king_square(them); + st->pinned[them] = hidden_checks(them, ksq, p1) | hidden_checks(them, ksq, p2); + st->pinners[them] = p1 | p2; + st->dcCandidates[us] = hidden_checks(us, ksq, p1) | hidden_checks(us, ksq, p2); +} -bool Position::pl_move_is_legal(Move m) const { +void Position::find_hidden_checks() { - return pl_move_is_legal(m, pinned_pieces(side_to_move())); + for (Color c = WHITE; c <= BLACK; c++) + find_hidden_checks(c); } -bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { + +/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal + +bool Position::pl_move_is_legal(Move m) const { assert(is_ok()); assert(move_is_ok(m)); - assert(pinned == pinned_pieces(side_to_move())); // If we're in check, all pseudo-legal moves are legal, because our // check evasion generator only generates true legal moves. @@ -498,7 +490,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Square ksq = king_square(us); assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == king_of_color(us)); + assert(piece_on(ksq) == piece_of_color_and_type(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 @@ -510,8 +502,8 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Bitboard b = occupied_squares(); assert(to == ep_square()); - assert(piece_on(from) == pawn_of_color(us)); - assert(piece_on(capsq) == pawn_of_color(them)); + assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); + assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); assert(piece_on(to) == EMPTY); clear_bit(&b, from); @@ -529,37 +521,27 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. - return ( !bit_is_set(pinned, from) + return ( !bit_is_set(pinned_pieces(us), from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } -/// Position::move_is_check() tests whether a pseudo-legal move is a check. -/// There are two versions of this function: One which takes only a move as -/// input, and one which takes a move and a bitboard of discovered check -/// candidates. The latter function is faster, and should always be preferred -/// when a discovered check candidates bitboard has already been computed. +/// Position::move_is_check() tests whether a pseudo-legal move is a check bool Position::move_is_check(Move m) const { - Bitboard dc = discovered_check_candidates(side_to_move()); - return move_is_check(m, dc); -} - -bool Position::move_is_check(Move m, Bitboard dcCandidates) const { - assert(is_ok()); assert(move_is_ok(m)); - assert(dcCandidates == discovered_check_candidates(side_to_move())); Color us = side_to_move(); Color them = opposite_color(us); Square from = move_from(m); Square to = move_to(m); Square ksq = king_square(them); + Bitboard dcCandidates = discovered_check_candidates(us); assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == king_of_color(them)); + assert(piece_on(ksq) == piece_of_color_and_type(them, KING)); // Proceed according to the type of the moving piece switch (type_of_piece_on(from)) @@ -664,93 +646,117 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { /// Position::move_is_capture() tests whether a move from the current -/// position is a capture. +/// position is a capture. Move must not be MOVE_NONE. bool Position::move_is_capture(Move m) const { + assert(m != MOVE_NONE); + return ( !square_is_empty(move_to(m)) - && (color_of_piece_on(move_to(m)) == opposite_color(side_to_move())) + && (color_of_piece_on(move_to(m)) != color_of_piece_on(move_from(m))) ) || move_is_ep(m); } -/// Position::backup() is called when making a move. All information -/// necessary to restore the position when the move is later unmade -/// is saved to an UndoInfo object. The function Position::restore -/// does the reverse operation: When one does a backup followed by -/// a restore with the same UndoInfo object, the position is restored -/// to the state before backup was called. - -void Position::backup(UndoInfo& u) const { - - u.castleRights = castleRights; - u.epSquare = epSquare; - u.checkersBB = checkersBB; - u.key = key; - u.pawnKey = pawnKey; - u.materialKey = materialKey; - u.rule50 = rule50; - u.lastMove = lastMove; - u.mgValue = mgValue; - u.egValue = egValue; - u.capture = NO_PIECE_TYPE; -} +/// Position::update_checkers() udpates chekers info given the move. It is called +/// in do_move() and is faster then find_checkers(). +template +inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, + Square to, Bitboard dcCandidates) { -/// Position::restore() is called when unmaking a move. It copies back -/// the information backed up during a previous call to Position::backup. + if (Piece != KING && bit_is_set(piece_attacks(ksq), to)) + set_bit(pCheckersBB, to); -void Position::restore(const UndoInfo& u) { + if (Piece != QUEEN && bit_is_set(dcCandidates, from)) + { + if (Piece != ROOK) + (*pCheckersBB) |= (piece_attacks(ksq) & rooks_and_queens(side_to_move())); - castleRights = u.castleRights; - epSquare = u.epSquare; - checkersBB = u.checkersBB; - key = u.key; - pawnKey = u.pawnKey; - materialKey = u.materialKey; - rule50 = u.rule50; - lastMove = u.lastMove; - mgValue = u.mgValue; - egValue = u.egValue; - // u.capture is restored in undo_move() + if (Piece != BISHOP) + (*pCheckersBB) |= (piece_attacks(ksq) & bishops_and_queens(side_to_move())); + } } -/// Position::do_move() makes a move, and backs up all information necessary -/// to undo the move to an UndoInfo object. The move is assumed to be legal. -/// Pseudo-legal moves should be filtered out before this function is called. -/// There are two versions of this function, one which takes only the move and -/// the UndoInfo as input, and one which takes a third parameter, a bitboard of -/// discovered check candidates. The second version is faster, because knowing -/// the discovered check candidates makes it easier to update the checkersBB -/// member variable in the position object. -void Position::do_move(Move m, UndoInfo& u) { +/// Position::update_hidden_checks() udpates pinned, pinners and dcCandidates +/// bitboards incrementally, given the move. It is called in do_move and is +/// faster then find_hidden_checks(). - do_move(m, u, discovered_check_candidates(side_to_move())); +void Position::update_hidden_checks(Square from, Square to) { + + Color us = sideToMove; + Color them = opposite_color(us); + Square ksq = king_square(opposite_color(us)); + + Bitboard moveSquares = EmptyBoardBB; + set_bit(&moveSquares, from); + set_bit(&moveSquares, to); + + // Our moving piece could have been a possible pinner or hidden checker behind a dcCandidates? + bool checkerMoved = (st->dcCandidates[us] | st->pinners[them]) && (moveSquares & sliders()); + + // If we are moving from/to an opponent king attack direction and we was a possible hidden checker + // or there exsist some possible hidden checker on that line then recalculate the position + // otherwise skip because our dcCandidates and opponent pinned pieces are not changed. + if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq])) + || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq]))) + find_hidden_checks(us); + + ksq = king_square(us); + + if (ksq == to) + { + find_hidden_checks(them); + return; + } + + // It is possible that we have captured an opponent hidden checker? + Bitboard checkerCaptured = (st->dcCandidates[them] | st->pinners[us]) && st->capture; + + // If we are moving from/to an our king attack direction and there was/is some possible + // opponent hidden checker then calculate the position otherwise skip because opponent + // dcCandidates and our pinned pieces are not changed. + if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerCaptured || (rooks_and_queens(them) & RookPseudoAttacks[ksq])) + || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerCaptured || (bishops_and_queens(them) & BishopPseudoAttacks[ksq]))) + find_hidden_checks(them); } -void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) { + +/// 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. + +void Position::do_move(Move m, StateInfo& newSt) { assert(is_ok()); assert(move_is_ok(m)); - // Back up the necessary information to our UndoInfo object (except the - // captured piece, which is taken care of later. - backup(u); + // Get now the current (before to move) dc candidates that we will use + // in update_checkers(). + Bitboard oldDcCandidates = discovered_check_candidates(side_to_move()); + + // Copy some fields of old state to our new StateInfo object (except the + // captured piece, which is taken care of later) and switch state pointer + // to point to the new, ready to be updated, state. + newSt = *st; + newSt.capture = NO_PIECE_TYPE; + newSt.previous = st; + st = &newSt; // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = key; + history[gamePly] = st->key; // Increment the 50 moves rule draw counter. Resetting it to zero in the // case of non-reversible moves is taken care of later. - rule50++; + st->rule50++; if (move_is_castle(m)) do_castle_move(m); else if (move_promotion(m)) - do_promotion_move(m, u); + do_promotion_move(m); else if (move_is_ep(m)) do_ep_move(m); else @@ -764,13 +770,11 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) { assert(color_of_piece_on(to) == them || piece_on(to) == EMPTY); PieceType piece = type_of_piece_on(from); - PieceType capture = type_of_piece_on(to); - if (capture) - { - u.capture = capture; - do_capture_move(m, capture, them, to); - } + st->capture = type_of_piece_on(to); + + if (st->capture) + do_capture_move(m, st->capture, them, to); // Move the piece clear_bit(&(byColorBB[us]), from); @@ -783,118 +787,80 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) { board[from] = EMPTY; // Update hash key - key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to]; + st->key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to]; // Update incremental scores - mgValue -= mg_pst(us, piece, from); - mgValue += mg_pst(us, piece, to); - egValue -= eg_pst(us, piece, from); - egValue += eg_pst(us, piece, to); + st->mgValue -= pst(us, piece, from); + st->mgValue += pst(us, piece, to); + st->egValue -= pst(us, piece, from); + st->egValue += pst(us, piece, to); // If the moving piece was a king, update the king square if (piece == KING) kingSquare[us] = to; - // If the move was a double pawn push, set the en passant square. - // This code is a bit ugly right now, and should be cleaned up later. - // FIXME - if (epSquare != SQ_NONE) + // Reset en passant square + if (st->epSquare != SQ_NONE) { - key ^= zobEp[epSquare]; - epSquare = SQ_NONE; + st->key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; } + + // If the moving piece was a pawn do some special extra work if (piece == PAWN) { + // Reset rule 50 draw counter + st->rule50 = 0; + + // Update pawn hash key + st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + + // Set en passant square, only if moved pawn can be captured if (abs(int(to) - int(from)) == 16) { - if( ( us == WHITE - && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK))) - || ( us == BLACK - && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE)))) + if ( (us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK))) + || (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE)))) { - epSquare = Square((int(from) + int(to)) / 2); - key ^= zobEp[epSquare]; + st->epSquare = Square((int(from) + int(to)) / 2); + st->key ^= zobEp[st->epSquare]; } } - // Reset rule 50 draw counter - rule50 = 0; - - // Update pawn hash key - pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; } + // Update piece lists pieceList[us][piece][index[from]] = to; index[to] = index[from]; // Update castle rights - key ^= zobCastle[castleRights]; - castleRights &= castleRightsMask[from]; - castleRights &= castleRightsMask[to]; - key ^= zobCastle[castleRights]; + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[from]; + st->castleRights &= castleRightsMask[to]; + st->key ^= zobCastle[st->castleRights]; - // Update checkers bitboard - checkersBB = EmptyBoardBB; + // Update checkers bitboard, piece must be already moved + st->checkersBB = EmptyBoardBB; Square ksq = king_square(them); switch (piece) { - case PAWN: - if (bit_is_set(pawn_attacks(them, ksq), to)) - set_bit(&checkersBB, to); - - if (bit_is_set(dcCandidates, from)) - checkersBB |= ( (piece_attacks(ksq) & rooks_and_queens(us)) - |(piece_attacks(ksq) & bishops_and_queens(us))); - break; - - case KNIGHT: - if (bit_is_set(piece_attacks(ksq), to)) - set_bit(&checkersBB, to); - - if (bit_is_set(dcCandidates, from)) - checkersBB |= ( (piece_attacks(ksq) & rooks_and_queens(us)) - |(piece_attacks(ksq) & bishops_and_queens(us))); - break; - - case BISHOP: - if (bit_is_set(piece_attacks(ksq), to)) - set_bit(&checkersBB, to); - - if (bit_is_set(dcCandidates, from)) - checkersBB |= (piece_attacks(ksq) & rooks_and_queens(us)); - break; - - case ROOK: - if (bit_is_set(piece_attacks(ksq), to)) - set_bit(&checkersBB, to); - - if (bit_is_set(dcCandidates, from)) - checkersBB |= (piece_attacks(ksq) & bishops_and_queens(us)); - break; - - case QUEEN: - if (bit_is_set(piece_attacks(ksq), to)) - set_bit(&checkersBB, to); - break; - - case KING: - if (bit_is_set(dcCandidates, from)) - checkersBB |= ( (piece_attacks(ksq) & rooks_and_queens(us)) - |(piece_attacks(ksq) & bishops_and_queens(us))); - break; - - default: - assert(false); - break; + case PAWN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case KNIGHT: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case BISHOP: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case ROOK: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case QUEEN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case KING: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + default: assert(false); break; } + + update_hidden_checks(from, to); } // Finish - key ^= zobSideToMove; + st->key ^= zobSideToMove; sideToMove = opposite_color(sideToMove); gamePly++; - mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; + st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; assert(is_ok()); } @@ -912,15 +878,15 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to) clear_bit(&(byTypeBB[capture]), to); // Update hash key - key ^= zobrist[them][capture][to]; + st->key ^= zobrist[them][capture][to]; // If the captured piece was a pawn, update pawn hash key if (capture == PAWN) - pawnKey ^= zobrist[them][PAWN][to]; + st->pawnKey ^= zobrist[them][PAWN][to]; // Update incremental scores - mgValue -= mg_pst(them, capture, to); - egValue -= eg_pst(them, capture, to); + st->mgValue -= pst(them, capture, to); + st->egValue -= pst(them, capture, to); assert(!move_promotion(m) || capture != PAWN); @@ -929,7 +895,7 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to) npMaterial[them] -= piece_value_midgame(capture); // Update material hash key - materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]]; + st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]]; // Update piece count pieceCount[them][capture]--; @@ -939,7 +905,7 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to) index[pieceList[them][capture][index[to]]] = index[to]; // Reset rule 50 counter - rule50 = 0; + st->rule50 = 0; } @@ -962,8 +928,8 @@ void Position::do_castle_move(Move m) { Square rfrom = move_to(m); // HACK: See comment at beginning of function Square kto, rto; - assert(piece_on(kfrom) == king_of_color(us)); - assert(piece_on(rfrom) == rook_of_color(us)); + assert(piece_on(kfrom) == piece_of_color_and_type(us, KING)); + assert(piece_on(rfrom) == piece_of_color_and_type(us, ROOK)); // Find destination squares for king and rook if (rfrom > kfrom) // O-O @@ -993,8 +959,8 @@ void Position::do_castle_move(Move m) { // Update board array board[kfrom] = board[rfrom] = EMPTY; - board[kto] = king_of_color(us); - board[rto] = rook_of_color(us); + board[kto] = piece_of_color_and_type(us, KING); + board[rto] = piece_of_color_and_type(us, ROOK); // Update king square kingSquare[us] = kto; @@ -1007,49 +973,50 @@ void Position::do_castle_move(Move m) { index[rto] = tmp; // Update incremental scores - mgValue -= mg_pst(us, KING, kfrom); - mgValue += mg_pst(us, KING, kto); - egValue -= eg_pst(us, KING, kfrom); - egValue += eg_pst(us, KING, kto); - mgValue -= mg_pst(us, ROOK, rfrom); - mgValue += mg_pst(us, ROOK, rto); - egValue -= eg_pst(us, ROOK, rfrom); - egValue += eg_pst(us, ROOK, rto); + st->mgValue -= pst(us, KING, kfrom); + st->mgValue += pst(us, KING, kto); + st->egValue -= pst(us, KING, kfrom); + st->egValue += pst(us, KING, kto); + st->mgValue -= pst(us, ROOK, rfrom); + st->mgValue += pst(us, ROOK, rto); + st->egValue -= pst(us, ROOK, rfrom); + st->egValue += pst(us, ROOK, rto); // Update hash key - key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; - key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; + 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(epSquare != SQ_NONE) + if (st->epSquare != SQ_NONE) { - key ^= zobEp[epSquare]; - epSquare = SQ_NONE; + st->key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; } // Update castling rights - key ^= zobCastle[castleRights]; - castleRights &= castleRightsMask[kfrom]; - key ^= zobCastle[castleRights]; + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[kfrom]; + st->key ^= zobCastle[st->castleRights]; // Reset rule 50 counter - rule50 = 0; + st->rule50 = 0; // Update checkers BB - checkersBB = attacks_to(king_square(them), us); + st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); } /// Position::do_promotion_move() is a private method used to make a promotion -/// move. It is called from the main Position::do_move function. The -/// UndoInfo object, which has been initialized in Position::do_move, is -/// used to store the captured piece (if any). +/// move. It is called from the main Position::do_move function. -void Position::do_promotion_move(Move m, UndoInfo &u) { +void Position::do_promotion_move(Move m) { Color us, them; Square from, to; - PieceType capture, promotion; + PieceType promotion; assert(is_ok()); assert(move_is_ok(m)); @@ -1061,16 +1028,13 @@ void Position::do_promotion_move(Move m, UndoInfo &u) { to = move_to(m); assert(relative_rank(us, to) == RANK_8); - assert(piece_on(from) == pawn_of_color(us)); + assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); assert(color_of_piece_on(to) == them || square_is_empty(to)); - capture = type_of_piece_on(to); + st->capture = type_of_piece_on(to); - if (capture) - { - u.capture = capture; - do_capture_move(m, capture, them, to); - } + if (st->capture) + do_capture_move(m, st->capture, them, to); // Remove pawn clear_bit(&(byColorBB[us]), from); @@ -1087,14 +1051,14 @@ void Position::do_promotion_move(Move m, UndoInfo &u) { board[to] = piece_of_color_and_type(us, promotion); // Update hash key - key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to]; + st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to]; // Update pawn hash key - pawnKey ^= zobrist[us][PAWN][from]; + st->pawnKey ^= zobrist[us][PAWN][from]; // Update material key - materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; - materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; + st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; + st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; // Update piece counts pieceCount[us][PAWN]--; @@ -1107,38 +1071,39 @@ void Position::do_promotion_move(Move m, UndoInfo &u) { index[to] = pieceCount[us][promotion] - 1; // Update incremental scores - mgValue -= mg_pst(us, PAWN, from); - mgValue += mg_pst(us, promotion, to); - egValue -= eg_pst(us, PAWN, from); - egValue += eg_pst(us, promotion, to); + st->mgValue -= pst(us, PAWN, from); + st->mgValue += pst(us, promotion, to); + st->egValue -= pst(us, PAWN, from); + st->egValue += pst(us, promotion, to); // Update material npMaterial[us] += piece_value_midgame(promotion); // Clear the en passant square - if (epSquare != SQ_NONE) + if (st->epSquare != SQ_NONE) { - key ^= zobEp[epSquare]; - epSquare = SQ_NONE; + st->key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; } // Update castle rights - key ^= zobCastle[castleRights]; - castleRights &= castleRightsMask[to]; - key ^= zobCastle[castleRights]; + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[to]; + st->key ^= zobCastle[st->castleRights]; // Reset rule 50 counter - rule50 = 0; + st->rule50 = 0; // Update checkers BB - checkersBB = attacks_to(king_square(them), us); + st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); } /// Position::do_ep_move() is a private method used to make an en passant -/// capture. It is called from the main Position::do_move function. Because -/// the captured piece is always a pawn, we don't need to pass an UndoInfo -/// object in which to store the captured piece. +/// capture. It is called from the main Position::do_move function. void Position::do_ep_move(Move m) { @@ -1155,11 +1120,11 @@ void Position::do_ep_move(Move m) { to = move_to(m); capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - assert(to == epSquare); + assert(to == st->epSquare); assert(relative_rank(us, to) == RANK_6); assert(piece_on(to) == EMPTY); - assert(piece_on(from) == pawn_of_color(us)); - assert(piece_on(capsq) == pawn_of_color(them)); + assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); + assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN)); // Remove captured piece clear_bit(&(byColorBB[them]), capsq); @@ -1180,7 +1145,7 @@ void Position::do_ep_move(Move m) { board[from] = EMPTY; // Update material hash key - materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]]; + st->materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]]; // Update piece count pieceCount[them][PAWN]--; @@ -1192,39 +1157,40 @@ void Position::do_ep_move(Move m) { index[pieceList[them][PAWN][index[capsq]]] = index[capsq]; // Update hash key - key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - key ^= zobrist[them][PAWN][capsq]; - key ^= zobEp[epSquare]; + st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + st->key ^= zobrist[them][PAWN][capsq]; + st->key ^= zobEp[st->epSquare]; // Update pawn hash key - pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; - pawnKey ^= zobrist[them][PAWN][capsq]; + st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + st->pawnKey ^= zobrist[them][PAWN][capsq]; // Update incremental scores - mgValue -= mg_pst(them, PAWN, capsq); - mgValue -= mg_pst(us, PAWN, from); - mgValue += mg_pst(us, PAWN, to); - egValue -= eg_pst(them, PAWN, capsq); - egValue -= eg_pst(us, PAWN, from); - egValue += eg_pst(us, PAWN, to); + st->mgValue -= pst(them, PAWN, capsq); + st->mgValue -= pst(us, PAWN, from); + st->mgValue += pst(us, PAWN, to); + st->egValue -= pst(them, PAWN, capsq); + st->egValue -= pst(us, PAWN, from); + st->egValue += pst(us, PAWN, to); // Reset en passant square - epSquare = SQ_NONE; + st->epSquare = SQ_NONE; // Reset rule 50 counter - rule50 = 0; + st->rule50 = 0; // Update checkers BB - checkersBB = attacks_to(king_square(them), us); + st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); } -/// Position::undo_move() unmakes a move. When it returns, the position should -/// be restored to exactly the same state as before the move was made. It is -/// important that Position::undo_move is called with the same move and UndoInfo -/// object as the earlier call to Position::do_move. +/// Position::undo_move() unmakes a move. When it returns, the position should +/// be restored to exactly the same state as before the move was made. -void Position::undo_move(Move m, const UndoInfo &u) { +void Position::undo_move(Move m) { assert(is_ok()); assert(move_is_ok(m)); @@ -1232,21 +1198,17 @@ void Position::undo_move(Move m, const UndoInfo &u) { gamePly--; sideToMove = opposite_color(sideToMove); - // Restore information from our UndoInfo object (except the captured piece, - // which is taken care of later) - restore(u); - if (move_is_castle(m)) undo_castle_move(m); else if (move_promotion(m)) - undo_promotion_move(m, u); + undo_promotion_move(m); else if (move_is_ep(m)) undo_ep_move(m); else { Color us, them; Square from, to; - PieceType piece, capture; + PieceType piece; us = side_to_move(); them = opposite_color(us); @@ -1276,32 +1238,33 @@ void Position::undo_move(Move m, const UndoInfo &u) { pieceList[us][piece][index[to]] = from; index[from] = index[to]; - capture = u.capture; - - if (capture) + if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Replace the captured piece set_bit(&(byColorBB[them]), to); - set_bit(&(byTypeBB[capture]), to); + set_bit(&(byTypeBB[st->capture]), to); set_bit(&(byTypeBB[0]), to); - board[to] = piece_of_color_and_type(them, capture); + board[to] = piece_of_color_and_type(them, st->capture); // Update material - if (capture != PAWN) - npMaterial[them] += piece_value_midgame(capture); + if (st->capture != PAWN) + npMaterial[them] += piece_value_midgame(st->capture); // Update piece list - pieceList[them][capture][pieceCount[them][capture]] = to; - index[to] = pieceCount[them][capture]; + pieceList[them][st->capture][pieceCount[them][st->capture]] = to; + index[to] = pieceCount[them][st->capture]; // Update piece count - pieceCount[them][capture]++; + pieceCount[them][st->capture]++; } else board[to] = EMPTY; } + // Finally point out state pointer back to the previous state + st = st->previous; + assert(is_ok()); } @@ -1336,8 +1299,8 @@ void Position::undo_castle_move(Move m) { rto = relative_square(us, SQ_D1); } - assert(piece_on(kto) == king_of_color(us)); - assert(piece_on(rto) == rook_of_color(us)); + 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); @@ -1357,8 +1320,8 @@ void Position::undo_castle_move(Move m) { // Update board board[rto] = board[kto] = EMPTY; - board[rfrom] = rook_of_color(us); - board[kfrom] = king_of_color(us); + board[rfrom] = piece_of_color_and_type(us, ROOK); + board[kfrom] = piece_of_color_and_type(us, KING); // Update king square kingSquare[us] = kfrom; @@ -1374,14 +1337,13 @@ void Position::undo_castle_move(Move m) { /// Position::undo_promotion_move() is a private method used to unmake a /// promotion move. It is called from the main Position::do_move -/// function. The UndoInfo object, which has been initialized in -/// Position::do_move, is used to put back the captured piece (if any). +/// function. -void Position::undo_promotion_move(Move m, const UndoInfo &u) { +void Position::undo_promotion_move(Move m) { Color us, them; Square from, to; - PieceType capture, promotion; + PieceType promotion; assert(move_is_ok(m)); assert(move_promotion(m)); @@ -1409,7 +1371,7 @@ void Position::undo_promotion_move(Move m, const UndoInfo &u) { set_bit(&(byColorBB[us]), from); set_bit(&(byTypeBB[PAWN]), from); set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares - board[from] = pawn_of_color(us); + board[from] = piece_of_color_and_type(us, PAWN); // Update material npMaterial[us] -= piece_value_midgame(promotion); @@ -1425,38 +1387,34 @@ void Position::undo_promotion_move(Move m, const UndoInfo &u) { pieceCount[us][promotion]--; pieceCount[us][PAWN]++; - capture = u.capture; - - if (capture) + if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Insert captured piece: set_bit(&(byColorBB[them]), to); - set_bit(&(byTypeBB[capture]), to); + set_bit(&(byTypeBB[st->capture]), to); set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares - board[to] = piece_of_color_and_type(them, capture); + board[to] = piece_of_color_and_type(them, st->capture); // Update material. Because the move is a promotion move, we know // that the captured piece cannot be a pawn. - assert(capture != PAWN); - npMaterial[them] += piece_value_midgame(capture); + assert(st->capture != PAWN); + npMaterial[them] += piece_value_midgame(st->capture); // Update piece list - pieceList[them][capture][pieceCount[them][capture]] = to; - index[to] = pieceCount[them][capture]; + pieceList[them][st->capture][pieceCount[them][st->capture]] = to; + index[to] = pieceCount[them][st->capture]; // Update piece count - pieceCount[them][capture]++; + pieceCount[them][st->capture]++; } else board[to] = EMPTY; } /// Position::undo_ep_move() is a private method used to unmake an en passant -/// capture. It is called from the main Position::undo_move function. Because -/// the captured piece is always a pawn, we don't need to pass an UndoInfo -/// object from which to retrieve the captured piece. +/// capture. It is called from the main Position::undo_move function. void Position::undo_ep_move(Move m) { @@ -1472,9 +1430,9 @@ void Position::undo_ep_move(Move m) { Square to = move_to(m); Square capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - assert(to == ep_square()); + assert(to == st->previous->epSquare); assert(relative_rank(us, to) == RANK_6); - assert(piece_on(to) == pawn_of_color(us)); + assert(piece_on(to) == piece_of_color_and_type(us, PAWN)); assert(piece_on(from) == EMPTY); assert(piece_on(capsq) == EMPTY); @@ -1482,7 +1440,7 @@ void Position::undo_ep_move(Move m) { set_bit(&(byColorBB[them]), capsq); set_bit(&(byTypeBB[PAWN]), capsq); set_bit(&(byTypeBB[0]), capsq); - board[capsq] = pawn_of_color(them); + board[capsq] = piece_of_color_and_type(them, PAWN); // Remove moving piece from destination square clear_bit(&(byColorBB[us]), to); @@ -1494,7 +1452,7 @@ void Position::undo_ep_move(Move m) { set_bit(&(byColorBB[us]), from); set_bit(&(byTypeBB[PAWN]), from); set_bit(&(byTypeBB[0]), from); - board[from] = pawn_of_color(us); + board[from] = piece_of_color_and_type(us, PAWN); // Update piece list: pieceList[us][PAWN][index[to]] = from; @@ -1510,33 +1468,35 @@ void Position::undo_ep_move(Move m) { /// Position::do_null_move makes() a "null move": It switches the side to move /// and updates the hash key without executing any move on the board. -void Position::do_null_move(UndoInfo &u) { +void Position::do_null_move(StateInfo& newSt) { assert(is_ok()); assert(!is_check()); // Back up the information necessary to undo the null move to the supplied - // UndoInfo object. In the case of a null move, the only thing we need to + // StateInfo object. In the case of a null move, the only thing we need to // remember is the last move made and the en passant square. - u.lastMove = lastMove; - u.epSquare = epSquare; + newSt.lastMove = st->lastMove; + newSt.epSquare = st->epSquare; + newSt.previous = st->previous; + st->previous = &newSt; // Save the current key to the history[] array, in order to be able to // detect repetition draws. - history[gamePly] = key; + history[gamePly] = st->key; // Update the necessary information sideToMove = opposite_color(sideToMove); - if (epSquare != SQ_NONE) - key ^= zobEp[epSquare]; + if (st->epSquare != SQ_NONE) + st->key ^= zobEp[st->epSquare]; - epSquare = SQ_NONE; - rule50++; + st->epSquare = SQ_NONE; + st->rule50++; gamePly++; - key ^= zobSideToMove; + st->key ^= zobSideToMove; - mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; + st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; assert(is_ok()); } @@ -1544,35 +1504,43 @@ void Position::do_null_move(UndoInfo &u) { /// Position::undo_null_move() unmakes a "null move". -void Position::undo_null_move(const UndoInfo &u) { +void Position::undo_null_move() { assert(is_ok()); assert(!is_check()); - // Restore information from the supplied UndoInfo object: - lastMove = u.lastMove; - epSquare = u.epSquare; - if (epSquare != SQ_NONE) - key ^= zobEp[epSquare]; + // Restore information from the our StateInfo object + st->lastMove = st->previous->lastMove; + st->epSquare = st->previous->epSquare; + st->previous = st->previous->previous; + + if (st->epSquare != SQ_NONE) + st->key ^= zobEp[st->epSquare]; - // Update the necessary information. + // Update the necessary information sideToMove = opposite_color(sideToMove); - rule50--; + st->rule50--; gamePly--; - key ^= zobSideToMove; + st->key ^= zobSideToMove; - mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; + st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; assert(is_ok()); } -/// Position::see() is a static exchange evaluator: It tries to estimate the -/// material gain or loss resulting from a move. There are two versions of -/// this function: One which takes a move as input, and one which takes a -/// 'from' and a 'to' square. The function does not yet understand promotions -/// or en passant captures. +/// Position::see() is a static exchange evaluator: It tries to estimate the +/// material gain or loss resulting from a move. There are three versions of +/// this function: One which takes a destination square as input, one takes a +/// move, and one which takes a 'from' and a 'to' square. The function does +/// not yet understand promotions captures. + +int Position::see(Square to) const { + + assert(square_is_ok(to)); + return see(SQ_NONE, to); +} int Position::see(Move m) const { @@ -1582,20 +1550,29 @@ int Position::see(Move m) const { int Position::see(Square from, Square to) const { - // Approximate material values, with pawn = 1 + // Material values static const int seeValues[18] = { - 0, 1, 3, 3, 5, 10, 100, 0, 0, 1, 3, 3, 5, 10, 100, 0, 0, 0 + 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, + RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0, + 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame, + RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0, + 0, 0 }; Bitboard attackers, occ, b; - assert(square_is_ok(from)); + assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); // Initialize colors - Color us = color_of_piece_on(from); + Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to))); Color them = opposite_color(us); + // Initialize pinned and pinners bitboards + Bitboard pinned[2], pinners[2]; + pinned[us] = pinned_pieces(us, pinners[us]); + pinned[them] = pinned_pieces(them, pinners[them]); + // Initialize pieces Piece piece = piece_on(from); Piece capture = piece_on(to); @@ -1603,15 +1580,60 @@ 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. occ = occupied_squares(); - clear_bit(&occ, from); - attackers = (rook_attacks_bb(to, occ) & rooks_and_queens()) - | (bishop_attacks_bb(to, occ) & bishops_and_queens()) - | (piece_attacks(to) & knights()) - | (piece_attacks(to) & kings()) - | (pawn_attacks(WHITE, to) & pawns(BLACK)) - | (pawn_attacks(BLACK, to) & pawns(WHITE)); - - // If the opponent has no attackers, we are finished + + // Handle en passant moves + if (st->epSquare == to && type_of_piece_on(from) == PAWN) + { + assert(capture == EMPTY); + + Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S); + capture = piece_on(capQq); + + assert(type_of_piece_on(capQq) == PAWN); + + // Remove the captured pawn + clear_bit(&occ, capQq); + } + + while (true) + { + clear_bit(&occ, from); + attackers = (rook_attacks_bb(to, occ) & rooks_and_queens()) + | (bishop_attacks_bb(to, occ) & bishops_and_queens()) + | (piece_attacks(to) & knights()) + | (piece_attacks(to) & kings()) + | (pawn_attacks(WHITE, to) & pawns(BLACK)) + | (pawn_attacks(BLACK, to) & pawns(WHITE)); + + // Remove our pinned pieces from attacks if the captured piece is not + // a pinner, otherwise we could remove a valid "capture the pinner" attack. + if (pinned[us] != EmptyBoardBB && !bit_is_set(pinners[us], to)) + attackers &= ~pinned[us]; + + // Remove opponent pinned pieces from attacks if the moving piece is not + // a pinner, otherwise we could remove a piece that is no more pinned + // due to our pinner piece is moving away. + if (pinned[them] != EmptyBoardBB && !bit_is_set(pinners[them], from)) + attackers &= ~pinned[them]; + + if (from != SQ_NONE) + break; + + // If we don't have any attacker we are finished + if ((attackers & pieces_of_color(us)) == EmptyBoardBB) + return 0; + + // Locate the least valuable attacker to the destination square + // and use it to initialize from square. + PieceType pt; + for (pt = PAWN; !(attackers & pieces_of_color_and_type(us, pt)); pt++) + assert(pt < KING); + + from = first_1(attackers & pieces_of_color_and_type(us, pt)); + piece = piece_on(from); + } + + // If the opponent has no attackers we are finished if ((attackers & pieces_of_color(them)) == EmptyBoardBB) return seeValues[capture]; @@ -1631,7 +1653,7 @@ int Position::see(Square from, Square to) const { swapList[0] = seeValues[capture]; do { - // Locate the least valuable attacker for the side to move. The loop + // Locate the least valuable attacker for the side to move. The loop // below looks like it is potentially infinite, but it isn't. We know // that the side to move still has at least one attacker left. for (pt = PAWN; !(attackers & pieces_of_color_and_type(c, pt)); pt++) @@ -1656,6 +1678,12 @@ int Position::see(Square from, Square to) const { lastCapturingPieceValue = seeValues[pt]; c = opposite_color(c); + // Remove pinned pieces from attackers + if ( pinned[c] != EmptyBoardBB + && !bit_is_set(pinners[c], to) + && !(pinners[c] & attackers)) + attackers &= ~pinned[c]; + // Stop after a king capture if (pt == KING && (attackers & pieces_of_color(c))) { @@ -1674,19 +1702,32 @@ int Position::see(Square from, Square to) const { } +/// Position::setStartState() copies the content of the argument +/// inside startState and makes st point to it. This is needed +/// when the st pointee could become stale, as example because +/// the caller is about to going out of scope. + +void Position::setStartState(const StateInfo& s) { + + startState = s; + st = &startState; +} + + /// Position::clear() erases the position object to a pristine state, with an /// empty board, white to move, and no castling rights. void Position::clear() { + st = &startState; + memset(st, 0, sizeof(StateInfo)); + st->epSquare = SQ_NONE; + + memset(index, 0, sizeof(int) * 64); + memset(byColorBB, 0, sizeof(Bitboard) * 2); + for (int i = 0; i < 64; i++) - { board[i] = EMPTY; - index[i] = 0; - } - - for (int i = 0; i < 2; i++) - byColorBB[i] = EmptyBoardBB; for (int i = 0; i < 7; i++) { @@ -1696,22 +1737,15 @@ void Position::clear() { pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; } - checkersBB = EmptyBoardBB; - - lastMove = MOVE_NONE; - sideToMove = WHITE; - castleRights = NO_CASTLES; + gamePly = 0; initialKFile = FILE_E; initialKRFile = FILE_H; initialQRFile = FILE_A; - epSquare = SQ_NONE; - rule50 = 0; - gamePly = 0; } -/// Position::reset_game_ply() simply sets gamePly to 0. It is used from the +/// 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 @@ -1751,7 +1785,7 @@ void Position::put_piece(Piece p, Square s) { void Position::allow_oo(Color c) { - castleRights |= (1 + int(c)); + st->castleRights |= (1 + int(c)); } @@ -1760,7 +1794,7 @@ void Position::allow_oo(Color c) { void Position::allow_ooo(Color c) { - castleRights |= (4 + 4*int(c)); + st->castleRights |= (4 + 4*int(c)); } @@ -1780,7 +1814,7 @@ Key Position::compute_key() const { if (ep_square() != SQ_NONE) result ^= zobEp[ep_square()]; - result ^= zobCastle[castleRights]; + result ^= zobCastle[st->castleRights]; if (side_to_move() == BLACK) result ^= zobSideToMove; @@ -1788,7 +1822,7 @@ Key Position::compute_key() const { } -/// Position::compute_pawn_key() computes the hash key of the position. The +/// Position::compute_pawn_key() computes the hash key of the position. The /// hash key is usually updated incrementally as moves are made and unmade, /// the compute_pawn_key() function is only used when a new position is set /// up, and to verify the correctness of the pawn hash key when running in @@ -1833,13 +1867,12 @@ Key Position::compute_material_key() const { } -/// Position::compute_mg_value() and Position::compute_eg_value() compute the -/// incremental scores for the middle game and the endgame. These functions -/// are used to initialize the incremental scores when a new position is set -/// up, and to verify that the scores are correctly updated by do_move -/// and undo_move when the program is running in debug mode. - -Value Position::compute_mg_value() const { +/// Position::compute_value() compute the incremental scores for the middle +/// game and the endgame. These functions are used to initialize the incremental +/// scores when a new position is set up, and to verify that the scores are correctly +/// updated by do_move and undo_move when the program is running in debug mode. +template +Value Position::compute_value() const { Value result = Value(0); Bitboard b; @@ -1853,37 +1886,18 @@ Value Position::compute_mg_value() const { { s = pop_1st_bit(&b); assert(piece_on(s) == piece_of_color_and_type(c, pt)); - result += mg_pst(c, pt, s); + result += pst(c, pt, s); } } - result += (side_to_move() == WHITE)? TempoValueMidgame / 2 : -TempoValueMidgame / 2; - return result; -} -Value Position::compute_eg_value() const { - - Value result = Value(0); - Bitboard b; - Square s; - - for (Color c = WHITE; c <= BLACK; c++) - for (PieceType pt = PAWN; pt <= KING; pt++) - { - b = pieces_of_color_and_type(c, pt); - while(b) - { - s = pop_1st_bit(&b); - assert(piece_on(s) == piece_of_color_and_type(c, pt)); - result += eg_pst(c, pt, s); - } - } - result += (side_to_move() == WHITE)? TempoValueEndgame / 2 : -TempoValueEndgame / 2; + const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame); + result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2; return result; } /// Position::compute_non_pawn_material() computes the total non-pawn middle -/// game material score for the given side. Material scores are updated +/// game material score for the given side. Material scores are updated /// incrementally during the search, this function is only used while /// initializing a new Position object. @@ -1910,7 +1924,7 @@ Value Position::compute_non_pawn_material(Color c) const { /// side to move is checkmated. Note that this function is currently very /// slow, and shouldn't be used frequently inside the search. -bool Position::is_mate() { +bool Position::is_mate() const { if (is_check()) { @@ -1922,7 +1936,7 @@ bool Position::is_mate() { /// Position::is_draw() tests whether the position is drawn by material, -/// repetition, or the 50 moves rule. It does not detect stalemates, this +/// repetition, or the 50 moves rule. It does not detect stalemates, this /// must be done by the search. bool Position::is_draw() const { @@ -1933,12 +1947,12 @@ bool Position::is_draw() const { return true; // Draw by the 50 moves rule? - if (rule50 > 100 || (rule50 == 100 && !is_check())) + if (st->rule50 > 100 || (st->rule50 == 100 && !is_check())) return true; // Draw by repetition? - for (int i = 2; i < Min(gamePly, rule50); i += 2) - if (history[gamePly - i] == key) + for (int i = 2; i < Min(gamePly, st->rule50); i += 2) + if (history[gamePly - i] == st->key) return true; return false; @@ -1951,21 +1965,21 @@ bool Position::is_draw() const { bool Position::has_mate_threat(Color c) { - UndoInfo u1, u2; + StateInfo st1, st2; Color stm = side_to_move(); // The following lines are useless and silly, but prevents gcc from // emitting a stupid warning stating that u1.lastMove and u1.epSquare might // be used uninitialized. - u1.lastMove = lastMove; - u1.epSquare = epSquare; + st1.lastMove = st->lastMove; + st1.epSquare = st->epSquare; if (is_check()) return false; // If the input color is not equal to the side to move, do a null move if (c != stm) - do_null_move(u1); + do_null_move(st1); MoveStack mlist[120]; int count; @@ -1977,16 +1991,16 @@ bool Position::has_mate_threat(Color c) { // Loop through the moves, and see if one of them is mate for (int i = 0; i < count; i++) { - do_move(mlist[i].move, u2); + do_move(mlist[i].move, st2); if (is_mate()) result = true; - undo_move(mlist[i].move, u2); + undo_move(mlist[i].move); } // Undo null move, if necessary if (c != stm) - undo_null_move(u1); + undo_null_move(); return result; } @@ -2048,7 +2062,7 @@ void Position::init_piece_square_tables() { /// Position::flipped_copy() makes a copy of the input position, but with -/// the white and black sides reversed. This is only useful for debugging, +/// 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) { @@ -2086,20 +2100,20 @@ void Position::flipped_copy(const Position &pos) { castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; // En passant square - if (pos.epSquare != SQ_NONE) - epSquare = flip_square(pos.epSquare); + if (pos.st->epSquare != SQ_NONE) + st->epSquare = flip_square(pos.st->epSquare); // Checkers find_checkers(); // Hash keys - key = compute_key(); - pawnKey = compute_pawn_key(); - materialKey = compute_material_key(); + st->key = compute_key(); + st->pawnKey = compute_pawn_key(); + st->materialKey = compute_material_key(); // Incremental scores - mgValue = compute_mg_value(); - egValue = compute_eg_value(); + st->mgValue = compute_value(); + st->egValue = compute_value(); // Material npMaterial[WHITE] = compute_non_pawn_material(WHITE); @@ -2159,7 +2173,7 @@ bool Position::is_ok(int* failedStep) const { if (type_of_piece_on(s) == KING) kingCount[color_of_piece_on(s)]++; - if(kingCount[0] != 1 || kingCount[1] != 1) + if (kingCount[0] != 1 || kingCount[1] != 1) return false; } @@ -2176,7 +2190,7 @@ bool Position::is_ok(int* failedStep) const { // Is there more than 2 checkers? if (failedStep) (*failedStep)++; - if (debugCheckerCount && count_1s(checkersBB) > 2) + if (debugCheckerCount && count_1s(st->checkersBB) > 2) return false; // Bitboards OK? @@ -2211,27 +2225,27 @@ bool Position::is_ok(int* failedStep) const { // Hash key OK? if (failedStep) (*failedStep)++; - if (debugKey && key != compute_key()) + if (debugKey && st->key != compute_key()) return false; // Pawn hash key OK? if (failedStep) (*failedStep)++; - if (debugPawnKey && pawnKey != compute_pawn_key()) + if (debugPawnKey && st->pawnKey != compute_pawn_key()) return false; // Material hash key OK? if (failedStep) (*failedStep)++; - if (debugMaterialKey && materialKey != compute_material_key()) + if (debugMaterialKey && st->materialKey != compute_material_key()) return false; // Incremental eval OK? if (failedStep) (*failedStep)++; if (debugIncrementalEval) { - if (mgValue != compute_mg_value()) + if (st->mgValue != compute_value()) return false; - if (egValue != compute_eg_value()) + if (st->egValue != compute_value()) return false; } @@ -2239,10 +2253,10 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) (*failedStep)++; if (debugNonPawnMaterial) { - if(npMaterial[WHITE] != compute_non_pawn_material(WHITE)) + if (npMaterial[WHITE] != compute_non_pawn_material(WHITE)) return false; - if(npMaterial[BLACK] != compute_non_pawn_material(BLACK)) + if (npMaterial[BLACK] != compute_non_pawn_material(BLACK)) return false; }