X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fposition.cpp;h=4935a2c643ed965992944a4563695619b7ac9b70;hb=e896368496d4156f3f8c1dda5a95686804088e73;hp=8408a8a3d1e29112428e2ddabb720f9184d8ebf6;hpb=782c3f36ccd4aeb52fd7eb92590d5e5e48741eaa;p=stockfish diff --git a/src/position.cpp b/src/position.cpp index 8408a8a3..4935a2c6 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -174,18 +174,41 @@ void Position::from_fen(const string& fenStr, bool isChess960) { sideToMove = (token == 'w' ? WHITE : BLACK); fen >> token; - // 3. Castling availability + // 3. Castling availability. Compatible with 3 standards: Normal FEN standard, + // Shredder-FEN that uses the letters of the columns on which the rooks began + // the game instead of KQkq and also X-FEN standard that, in case of Chess960, + // if an inner rook is associated with the castling right, the castling tag is + // replaced by the file letter of the involved rook, as for the Shredder-FEN. while ((fen >> token) && !isspace(token)) - set_castling_rights(token); + { + Square rsq; + Color c = islower(token) ? BLACK : WHITE; + Piece rook = make_piece(c, ROOK); + + token = char(toupper(token)); + + if (token == 'K') + for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; rsq--) {} + + else if (token == 'Q') + for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; rsq++) {} + + else if (token >= 'A' && token <= 'H') + rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + + else + continue; + + set_castle_right(king_square(c), rsq); + } // 4. En passant square. Ignore if no pawn capture is possible if ( ((fen >> col) && (col >= 'a' && col <= 'h')) && ((fen >> row) && (row == '3' || row == '6'))) { st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); - Color them = flip(sideToMove); - if (!(attacks_from(st->epSquare, them) & pieces(PAWN, sideToMove))) + if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove))) st->epSquare = SQ_NONE; } @@ -196,25 +219,25 @@ void Position::from_fen(const string& fenStr, bool isChess960) { // handle also common incorrect FEN with fullmove = 0. startPosPly = Max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK); - // Various initialisations - chess960 = isChess960; - st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove)); - st->key = compute_key(); st->pawnKey = compute_pawn_key(); st->materialKey = compute_material_key(); st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove)); + chess960 = isChess960; assert(pos_is_ok()); } -/// Position::set_castle() is an helper function used to set -/// correct castling related flags. +/// Position::set_castle_right() is an helper function used to set castling +/// rights given the corresponding king and rook starting squares. -void Position::set_castle(int f, Square ksq, Square rsq) { +void Position::set_castle_right(Square ksq, Square rsq) { + + int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq)); st->castleRights |= f; castleRightsMask[ksq] ^= f; @@ -223,41 +246,6 @@ void Position::set_castle(int f, Square ksq, Square rsq) { } -/// Position::set_castling_rights() sets castling parameters castling avaiability. -/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN -/// that uses the letters of the columns on which the rooks began the game instead -/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is -/// associated with the castling right, the traditional castling tag will be replaced -/// by the file letter of the involved rook as for the Shredder-FEN. - -void Position::set_castling_rights(char token) { - - 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); - - token = char(toupper(token)); - - if (token == 'K') - for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {} - - else if (token == 'Q') - for (rsq = sqA; piece_on(rsq) != make_piece(c, ROOK); rsq++) {} - - else if (token >= 'A' && token <= 'H') - rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); - - else return; - - if (file_of(rsq) < file_of(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. @@ -400,18 +388,8 @@ Bitboard Position::discovered_check_candidates() const { return hidden_checkers(); } -/// Position::attackers_to() computes a bitboard containing all pieces which -/// attacks a given square. - -Bitboard Position::attackers_to(Square s) const { - - return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) - | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) - | (attacks_from(s) & pieces(KNIGHT)) - | (attacks_from(s) & pieces(ROOK, QUEEN)) - | (attacks_from(s) & pieces(BISHOP, QUEEN)) - | (attacks_from(s) & pieces(KING)); -} +/// Position::attackers_to() computes a bitboard of all pieces which attacks a +/// given square. Slider attacks use occ bitboard as occupancy. Bitboard Position::attackers_to(Square s, Bitboard occ) const { @@ -423,21 +401,8 @@ Bitboard Position::attackers_to(Square s, Bitboard occ) const { | (attacks_from(s) & pieces(KING)); } -/// Position::attacks_from() computes a bitboard of all attacks -/// of a given piece put in a given square. - -Bitboard Position::attacks_from(Piece p, Square s) const { - - assert(square_is_ok(s)); - - switch (p) - { - case WB: case BB: return attacks_from(s); - case WR: case BR: return attacks_from(s); - case WQ: case BQ: return attacks_from(s); - default: return StepAttacksBB[p][s]; - } -} +/// Position::attacks_from() computes a bitboard of all attacks of a given piece +/// put in a given square. Slider attacks use occ bitboard as occupancy. Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { @@ -641,6 +606,9 @@ bool Position::is_pseudo_legal(const Move m) const { else if (!bit_is_set(attacks_from(pc, from), to)) return false; + // Evasions generator already takes care to avoid some kind of illegal moves + // and pl_move_is_legal() relies on this. So we have to take care that the + // same kind of moves are filtered out here. if (in_check()) { // In case of king moves under check we have to remove king so to catch @@ -708,20 +676,7 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { if (is_promotion(m)) { clear_bit(&b, from); - - switch (promotion_piece_type(m)) - { - case KNIGHT: - return bit_is_set(attacks_from(to), ksq); - case BISHOP: - return bit_is_set(bishop_attacks_bb(to, b), ksq); - case ROOK: - return bit_is_set(rook_attacks_bb(to, b), ksq); - case QUEEN: - return bit_is_set(queen_attacks_bb(to, b), ksq); - default: - assert(false); - } + return bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), ksq); } // En passant capture with check ? We have already handled the case @@ -809,7 +764,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (is_castle(m)) { st->key = key; - do_castle_move(m); + do_castle_move(m); return; } @@ -1038,39 +993,43 @@ void Position::do_capture_move(Key& key, PieceType capture, Color them, Square t } -/// Position::do_castle_move() is a private method used to make a castling -/// move. It is called from the main Position::do_move function. Note that -/// castling moves are encoded as "king captures friendly rook" moves, for -/// instance white short castling in a non-Chess960 game is encoded as e1h1. - +/// Position::do_castle_move() is a private method used to do/undo a castling +/// move. Note that castling moves are encoded as "king captures friendly rook" +/// moves, for instance white short castling in a non-Chess960 game is encoded +/// as e1h1. +template void Position::do_castle_move(Move m) { assert(is_ok(m)); assert(is_castle(m)); - Color us = side_to_move(); - Color them = flip(us); - - // Find source squares for king and rook - Square kfrom = move_from(m); - Square rfrom = move_to(m); - Square kto, rto; + Square kto, kfrom, rfrom, rto, kAfter, rAfter; - assert(piece_on(kfrom) == make_piece(us, KING)); - assert(piece_on(rfrom) == make_piece(us, ROOK)); + Color us = side_to_move(); + Square kBefore = move_from(m); + Square rBefore = move_to(m); - // Find destination squares for king and rook - if (rfrom > kfrom) // O-O + // Find after-castle squares for king and rook + if (rBefore > kBefore) // O-O { - kto = relative_square(us, SQ_G1); - rto = relative_square(us, SQ_F1); + kAfter = relative_square(us, SQ_G1); + rAfter = relative_square(us, SQ_F1); } else // O-O-O { - kto = relative_square(us, SQ_C1); - rto = relative_square(us, SQ_D1); + kAfter = relative_square(us, SQ_C1); + rAfter = relative_square(us, SQ_D1); } + kfrom = Do ? kBefore : kAfter; + rfrom = Do ? rBefore : rAfter; + + kto = Do ? kAfter : kBefore; + rto = Do ? rAfter : rBefore; + + assert(piece_on(kfrom) == make_piece(us, KING)); + assert(piece_on(rfrom) == make_piece(us, ROOK)); + // Remove pieces from source squares clear_bit(&byColorBB[us], kfrom); clear_bit(&byTypeBB[KING], kfrom); @@ -1101,38 +1060,44 @@ void Position::do_castle_move(Move m) { index[kto] = index[kfrom]; index[rto] = tmp; - // Reset capture field - st->capturedType = PIECE_TYPE_NONE; + if (Do) + { + // 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); + // Update incremental scores + st->value += pst_delta(king, kfrom, kto); + st->value += pst_delta(rook, rfrom, rto); - // Update hash key - st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; - st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; + // Update hash key + st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; + st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; - // Clear en passant square - if (st->epSquare != SQ_NONE) - { - st->key ^= zobEp[st->epSquare]; - st->epSquare = SQ_NONE; - } + // Clear en passant square + if (st->epSquare != SQ_NONE) + { + st->key ^= zobEp[st->epSquare]; + st->epSquare = SQ_NONE; + } - // Update castling rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[kfrom]; - st->key ^= zobCastle[st->castleRights]; + // Update castling rights + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[kfrom]; + st->key ^= zobCastle[st->castleRights]; - // Reset rule 50 counter - st->rule50 = 0; + // Reset rule 50 counter + st->rule50 = 0; - // Update checkers BB - st->checkersBB = attackers_to(king_square(them)) & pieces(us); + // Update checkers BB + st->checkersBB = attackers_to(king_square(flip(us))) & pieces(us); - // Finish - sideToMove = flip(sideToMove); - st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); + // Finish + sideToMove = flip(sideToMove); + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); + } + else + // Undo: point our state pointer back to the previous state + st = st->previous; assert(pos_is_ok()); } @@ -1149,7 +1114,7 @@ void Position::undo_move(Move m) { if (is_castle(m)) { - undo_castle_move(m); + do_castle_move(m); return; } @@ -1239,78 +1204,6 @@ void Position::undo_move(Move m) { } -/// Position::undo_castle_move() is a private method used to unmake a castling -/// move. It is called from the main Position::undo_move function. Note that -/// castling moves are encoded as "king captures friendly rook" moves, for -/// instance white short castling in a non-Chess960 game is encoded as e1h1. - -void Position::undo_castle_move(Move m) { - - assert(is_ok(m)); - assert(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, - // 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); - Square kto, rto; - - // Find destination squares for king and rook - if (rfrom > kfrom) // O-O - { - kto = relative_square(us, SQ_G1); - rto = relative_square(us, SQ_F1); - } - else // O-O-O - { - kto = relative_square(us, SQ_C1); - rto = relative_square(us, SQ_D1); - } - - 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 - 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; - pieceList[us][ROOK][index[rto]] = rfrom; - int tmp = index[rto]; // In Chess960 could be rto == kfrom - index[kfrom] = index[kto]; - index[rfrom] = tmp; - - // Finally point our state pointer back to the previous state - st = st->previous; - - assert(pos_is_ok()); -} - - /// Position::do_null_move makes() a "null move": It switches the side to move /// and updates the hash key without executing any move on the board. @@ -1384,7 +1277,7 @@ int Position::see_sign(Move m) const { // Early return if SEE cannot be negative because captured piece value // is not less then capturing one. Note that king moves always return // here because king midgame value is set to 0. - if (piece_value_midgame(piece_on(to)) >= piece_value_midgame(piece_on(from))) + if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)]) return 1; return see(m); @@ -1591,7 +1484,7 @@ Key Position::compute_material_key() const { for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= QUEEN; pt++) - for (int i = 0, cnt = piece_count(c, pt); i < cnt; i++) + for (int i = 0; i < piece_count(c, pt); i++) result ^= zobrist[c][pt][i]; return result; @@ -1689,12 +1582,11 @@ bool Position::is_mate() const { } -/// Position::init() is a static member function which initializes at -/// startup the various arrays used to compute hash keys and the piece -/// square tables. The latter is a two-step operation: First, the white -/// halves of the tables are copied from the MgPST[][] and EgPST[][] arrays. -/// Second, the black halves of the tables are initialized by flipping -/// and changing the sign of the corresponding white scores. +/// Position::init() is a static member function which initializes at startup +/// the various arrays used to compute hash keys and the piece square tables. +/// The latter is a two-step operation: First, the white halves of the tables +/// are copied from PSQT[] tables. Second, the black halves of the tables are +/// initialized by flipping and changing the sign of the white scores. void Position::init() { @@ -1715,11 +1607,15 @@ void Position::init() { zobExclusion = rk.rand(); for (Piece p = WP; p <= WK; p++) + { + Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]); + for (Square s = SQ_A1; s <= SQ_H8; s++) { - pieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]); + pieceSquareTable[p][s] = ps + PSQT[p][s]; pieceSquareTable[p+8][flip(s)] = -pieceSquareTable[p][s]; } + } } @@ -1744,13 +1640,13 @@ void Position::flip_me() { // Castling rights if (pos.can_castle(WHITE_OO)) - set_castle(BLACK_OO, king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO))); + set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO))); if (pos.can_castle(WHITE_OOO)) - set_castle(BLACK_OOO, king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO))); + set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO))); if (pos.can_castle(BLACK_OO)) - set_castle(WHITE_OO, king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO))); + set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO))); if (pos.can_castle(BLACK_OOO)) - set_castle(WHITE_OOO, king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO))); + set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO))); // En passant square if (pos.st->epSquare != SQ_NONE)