X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=197e1e31fa3c628ec59fa02182da53d60681af50;hp=ebbf82992273cd44b60d8a6d600b0626d5bdf63f;hb=1f4798a173ea6579ef42a423d71f2e36d3894a03;hpb=1e032ece92da0085000cfdde28cab05029dedce3 diff --git a/src/position.cpp b/src/position.cpp index ebbf8299..197e1e31 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -172,6 +172,21 @@ Position& Position::operator=(const Position& pos) { } +/// Position::clear() erases the position object to a pristine state, with an +/// empty board, white to move, and no castling rights. + +void Position::clear() { + + std::memset(this, 0, sizeof(Position)); + startState.epSquare = SQ_NONE; + st = &startState; + + for (int i = 0; i < PIECE_TYPE_NB; ++i) + for (int j = 0; j < 16; ++j) + pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE; +} + + /// Position::set() initializes the position object with the given FEN string. /// This function is not very robust - make sure that input FENs are correct, /// this is assumed to be the responsibility of the GUI. @@ -284,12 +299,9 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { // handle also common incorrect FEN with fullmove = 0. gamePly = std::max(2 * (gamePly - 1), 0) + int(sideToMove == BLACK); - compute_keys(st); - compute_non_pawn_material(st); - st->psq = compute_psq_score(); - st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); chess960 = isChess960; thisThread = th; + set_state(st); assert(pos_is_ok()); } @@ -322,6 +334,52 @@ void Position::set_castling_right(Color c, Square rfrom) { } +/// Position::set_state() computes the hash keys of the position, and other +/// data that once computed is updated incrementally as moves are made. +/// The function is only used when a new position is set up, and to verify +/// the correctness of the StateInfo data when running in debug mode. + +void Position::set_state(StateInfo* si) const { + + si->key = si->pawnKey = si->materialKey = 0; + si->npMaterial[WHITE] = si->npMaterial[BLACK] = VALUE_ZERO; + si->psq = SCORE_ZERO; + + si->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); + + for (Bitboard b = pieces(); b; ) + { + Square s = pop_lsb(&b); + Piece pc = piece_on(s); + si->key ^= Zobrist::psq[color_of(pc)][type_of(pc)][s]; + si->psq += psq[color_of(pc)][type_of(pc)][s]; + } + + if (ep_square() != SQ_NONE) + si->key ^= Zobrist::enpassant[file_of(ep_square())]; + + if (sideToMove == BLACK) + si->key ^= Zobrist::side; + + si->key ^= Zobrist::castling[st->castlingRights]; + + for (Bitboard b = pieces(PAWN); b; ) + { + Square s = pop_lsb(&b); + si->pawnKey ^= Zobrist::psq[color_of(piece_on(s))][PAWN][s]; + } + + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt = PAWN; pt <= KING; ++pt) + for (int cnt = 0; cnt < pieceCount[c][pt]; ++cnt) + si->materialKey ^= Zobrist::psq[c][pt][cnt]; + + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt = KNIGHT; pt <= QUEEN; ++pt) + si->npMaterial[c] += pieceCount[c][pt] * PieceValue[MG][pt]; +} + + /// Position::fen() returns a FEN representation of the position. In case of /// Chess960 the Shredder-FEN notation is used. This is mainly a debugging function. @@ -468,19 +526,18 @@ bool Position::legal(Move m, Bitboard pinned) const { // the move is made. if (type_of(m) == ENPASSANT) { - Color them = ~us; - Square to = to_sq(m); - Square capsq = to + pawn_push(them); Square ksq = king_square(us); - Bitboard b = (pieces() ^ from ^ capsq) | to; + Square to = to_sq(m); + Square capsq = to - pawn_push(us); + Bitboard occ = (pieces() ^ from ^ capsq) | to; assert(to == ep_square()); assert(moved_piece(m) == make_piece(us, PAWN)); - assert(piece_on(capsq) == make_piece(them, PAWN)); + assert(piece_on(capsq) == make_piece(~us, PAWN)); assert(piece_on(to) == NO_PIECE); - return !(attacks_bb< ROOK>(ksq, b) & pieces(them, QUEEN, ROOK)) - && !(attacks_bb(ksq, b) & pieces(them, QUEEN, BISHOP)); + return !(attacks_bb< ROOK>(ksq, occ) & pieces(~us, QUEEN, ROOK)) + && !(attacks_bb(ksq, occ) & pieces(~us, QUEEN, BISHOP)); } // If the moving piece is a king, check whether the destination @@ -681,14 +738,10 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI { assert(pc == make_piece(us, KING)); - bool kingSide = to > from; - Square rfrom = to; // Castling is encoded as "king captures friendly rook" - Square rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); - to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); - captured = NO_PIECE_TYPE; - - do_castling(from, to, rfrom, rto); + Square rfrom, rto; + do_castling(from, to, rfrom, rto); + captured = NO_PIECE_TYPE; st->psq += psq[us][ROOK][rto] - psq[us][ROOK][rfrom]; k ^= Zobrist::psq[us][ROOK][rfrom] ^ Zobrist::psq[us][ROOK][rto]; } @@ -875,13 +928,11 @@ void Position::undo_move(Move m) { if (type_of(m) == CASTLING) { - bool kingSide = to > from; - Square rfrom = to; // Castling is encoded as "king captures friendly rook" - Square rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); - to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); + Square rfrom, rto; + do_castling(from, to, rfrom, rto); + captured = NO_PIECE_TYPE; pt = KING; - do_castling(to, from, rto, rfrom); } else move_piece(to, from, us, pt); // Put the piece back at the source square @@ -913,15 +964,20 @@ void Position::undo_move(Move m) { /// Position::do_castling() is a helper used to do/undo a castling move. This /// is a bit tricky, especially in Chess960. +template +void Position::do_castling(Square from, Square& to, Square& rfrom, Square& rto) { -void Position::do_castling(Square kfrom, Square kto, Square rfrom, Square rto) { + bool kingSide = to > from; + rfrom = to; // Castling is encoded as "king captures friendly rook" + rto = relative_square(sideToMove, kingSide ? SQ_F1 : SQ_D1); + to = relative_square(sideToMove, kingSide ? SQ_G1 : SQ_C1); // Remove both pieces first since squares could overlap in Chess960 - remove_piece(kfrom, sideToMove, KING); - remove_piece(rfrom, sideToMove, ROOK); - board[kfrom] = board[rfrom] = NO_PIECE; // Since remove_piece doesn't do it for us - put_piece(kto, sideToMove, KING); - put_piece(rto, sideToMove, ROOK); + remove_piece(Do ? from : to, sideToMove, KING); + remove_piece(Do ? rfrom : rto, sideToMove, ROOK); + board[Do ? from : to] = board[Do ? rfrom : rto] = NO_PIECE; // Since remove_piece doesn't do it for us + put_piece(Do ? to : from, sideToMove, KING); + put_piece(Do ? rto : rfrom, sideToMove, ROOK); } @@ -1059,91 +1115,6 @@ Value Position::see(Move m) const { } -/// Position::clear() erases the position object to a pristine state, with an -/// empty board, white to move, and no castling rights. - -void Position::clear() { - - std::memset(this, 0, sizeof(Position)); - startState.epSquare = SQ_NONE; - st = &startState; - - for (int i = 0; i < PIECE_TYPE_NB; ++i) - for (int j = 0; j < 16; ++j) - pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE; -} - - -/// Position::compute_keys() computes the hash keys of the position, pawns and -/// material configuration. The hash keys are usually updated incrementally as -/// moves are made and unmade. The function is only used when a new position is -/// set up, and to verify the correctness of the keys when running in debug mode. - -void Position::compute_keys(StateInfo* si) const { - - si->key = si->pawnKey = si->materialKey = 0; - - for (Bitboard b = pieces(); b; ) - { - Square s = pop_lsb(&b); - si->key ^= Zobrist::psq[color_of(piece_on(s))][type_of(piece_on(s))][s]; - } - - if (ep_square() != SQ_NONE) - si->key ^= Zobrist::enpassant[file_of(ep_square())]; - - if (sideToMove == BLACK) - si->key ^= Zobrist::side; - - si->key ^= Zobrist::castling[st->castlingRights]; - - for (Bitboard b = pieces(PAWN); b; ) - { - Square s = pop_lsb(&b); - si->pawnKey ^= Zobrist::psq[color_of(piece_on(s))][PAWN][s]; - } - - for (Color c = WHITE; c <= BLACK; ++c) - for (PieceType pt = PAWN; pt <= KING; ++pt) - for (int cnt = 0; cnt < pieceCount[c][pt]; ++cnt) - si->materialKey ^= Zobrist::psq[c][pt][cnt]; -} - - -/// Position::compute_non_pawn_material() computes the total non-pawn middlegame -/// material value for each side. Material values are updated incrementally during -/// the search. This function is only used when initializing a new Position object. - -void Position::compute_non_pawn_material(StateInfo* si) const { - - si->npMaterial[WHITE] = si->npMaterial[BLACK] = VALUE_ZERO; - - for (Color c = WHITE; c <= BLACK; ++c) - for (PieceType pt = KNIGHT; pt <= QUEEN; ++pt) - si->npMaterial[c] += pieceCount[c][pt] * PieceValue[MG][pt]; -} - - -/// Position::compute_psq_score() computes the incremental scores for the middlegame -/// 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. - -Score Position::compute_psq_score() const { - - Score score = SCORE_ZERO; - - for (Bitboard b = pieces(); b; ) - { - Square s = pop_lsb(&b); - Piece pc = piece_on(s); - score += psq[color_of(pc)][type_of(pc)][s]; - } - - return score; -} - - /// Position::is_draw() tests whether the position is drawn by material, 50 moves /// rule or repetition. It does not detect stalemates. @@ -1214,16 +1185,13 @@ bool Position::pos_is_ok(int* failedStep) const { int dummy, *step = failedStep ? failedStep : &dummy; - // What features of the position should be verified? + // Which parts of the position should be verified? const bool all = false; const bool testBitboards = all || false; + const bool testState = all || false; const bool testKingCount = all || false; const bool testKingCapture = all || false; - const bool testCheckerCount = all || false; - const bool testKeys = all || false; - const bool testIncrementalEval = all || false; - const bool testNonPawnMaterial = all || false; const bool testPieceCounts = all || false; const bool testPieceList = all || false; const bool testCastlingSquares = all || false; @@ -1237,16 +1205,7 @@ bool Position::pos_is_ok(int* failedStep) const { if ((*step)++, piece_on(king_square(BLACK)) != B_KING) return false; - if ((*step)++, testKingCount) - if ( std::count(board, board + SQUARE_NB, W_KING) != 1 - || std::count(board, board + SQUARE_NB, B_KING) != 1) - return false; - - if ((*step)++, testKingCapture) - if (attackers_to(king_square(~sideToMove)) & pieces(sideToMove)) - return false; - - if ((*step)++, testCheckerCount && popcount(st->checkersBB) > 2) + if ((*step)++, ep_square() != SQ_NONE && relative_rank(sideToMove, ep_square()) != RANK_6) return false; if ((*step)++, testBitboards) @@ -1267,28 +1226,28 @@ bool Position::pos_is_ok(int* failedStep) const { return false; } - if ((*step)++, ep_square() != SQ_NONE && relative_rank(sideToMove, ep_square()) != RANK_6) - return false; - - if ((*step)++, testKeys) + if ((*step)++, testState) { StateInfo si; - compute_keys(&si); - if (st->key != si.key || st->pawnKey != si.pawnKey || st->materialKey != si.materialKey) + set_state(&si); + if ( st->key != si.key + || st->pawnKey != si.pawnKey + || st->materialKey != si.materialKey + || st->npMaterial[WHITE] != si.npMaterial[WHITE] + || st->npMaterial[BLACK] != si.npMaterial[BLACK] + || st->psq != si.psq + || st->checkersBB != si.checkersBB) return false; } - if ((*step)++, testNonPawnMaterial) - { - StateInfo si; - compute_non_pawn_material(&si); - if ( st->npMaterial[WHITE] != si.npMaterial[WHITE] - || st->npMaterial[BLACK] != si.npMaterial[BLACK]) + if ((*step)++, testKingCount) + if ( std::count(board, board + SQUARE_NB, W_KING) != 1 + || std::count(board, board + SQUARE_NB, B_KING) != 1) return false; - } - if ((*step)++, testIncrementalEval && st->psq != compute_psq_score()) - return false; + if ((*step)++, testKingCapture) + if (attackers_to(king_square(~sideToMove)) & pieces(sideToMove)) + return false; if ((*step)++, testPieceCounts) for (Color c = WHITE; c <= BLACK; ++c)