X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=591d48fbb41b3254bf8cef4c6a63edcebe91c94a;hp=9771bcff40d284e605e53187bc4d6c7b43754a64;hb=d3f99aea6b6a7653c2d60ac94e600b1b2f5800e1;hpb=43bc5479c2a9a4d3e4c3d2e982eb728bc8b0fd14 diff --git a/src/position.cpp b/src/position.cpp index 9771bcff..591d48fb 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -23,8 +23,9 @@ //// #include -#include +#include #include +#include #include "mersenne.h" #include "movegen.h" @@ -189,7 +190,7 @@ void Position::from_fen(const std::string& fen) { i++; // En passant square - if ( i < fen.length() - 2 + if ( i <= fen.length() - 2 && (fen[i] >= 'a' && fen[i] <= 'h') && (fen[i+1] == '3' || fen[i+1] == '6')) st->epSquare = square_from_string(fen.substr(i, 2)); @@ -319,85 +320,62 @@ 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 { +/// 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. +/// Note that checkersBB bitboard must be already updated. - if (st->pinned[c] != ~EmptyBoardBB) - return st->pinned[c]; +template +Bitboard Position::hidden_checkers(Color c) const { - Bitboard p1, p2; - Square ksq = king_square(c); - st->pinned[c] = hidden_checks(c, ksq, p1) | hidden_checks(c, ksq, p2); - st->pinners[c] = p1 | p2; - return st->pinned[c]; -} + Bitboard pinners, result = EmptyBoardBB; -Bitboard Position::pinned_pieces(Color c, Bitboard& p) const { + // Pinned pieces protect our king, dicovery checks attack + // the enemy king. + Square ksq = king_square(FindPinned ? c : opposite_color(c)); - if (st->pinned[c] == ~EmptyBoardBB) - pinned_pieces(c); + // Pinners are sliders, not checkers, that give check when + // candidate pinned is removed. + pinners = (rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]) + | (bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]); - p = st->pinners[c]; - return st->pinned[c]; -} + if (FindPinned && pinners) + pinners &= ~st->checkersBB; -Bitboard Position::discovered_check_candidates(Color c) const { + while (pinners) + { + Square s = pop_1st_bit(&pinners); + Bitboard b = squares_between(s, ksq) & occupied_squares(); - if (st->dcCandidates[c] != ~EmptyBoardBB) - return st->dcCandidates[c]; + assert(b); - Bitboard dummy; - Square ksq = king_square(opposite_color(c)); - st->dcCandidates[c] = hidden_checks(c, ksq, dummy) | hidden_checks(c, ksq, dummy); - return st->dcCandidates[c]; + if ( !(b & (b - 1)) // Only one bit set? + && (b & pieces_of_color(c))) // Is an our piece? + result |= b; + } + return result; } -/// 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. -template -Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const { - Square s; - Bitboard sliders, result = EmptyBoardBB; - - if (Piece == ROOK) // Resolved at compile time - sliders = rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]; - else - sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]; +/// Position:pinned_pieces() returns a bitboard of all pinned (against the +/// king) pieces for the given color. - 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. - pinners = (FindPinned ? sliders & ~st->checkersBB : sliders); - - if (Piece == ROOK) - pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); - else - pinners &= bishop_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); - - // Finally for each pinner find the corresponding pinned piece (if same color of king) - // or discovery checker (if opposite color) among the candidates. - Bitboard p = pinners; - while (p) - { - s = pop_1st_bit(&p); - result |= (squares_between(s, ksq) & candidate_pinned); - } - } - else - pinners = EmptyBoardBB; +Bitboard Position::pinned_pieces(Color c) const { - return result; + return hidden_checkers(c); } +/// Position:discovered_check_candidates() returns a bitboard containing all +/// pieces for the given side which are candidates for giving a discovered +/// check. + +Bitboard Position::discovered_check_candidates(Color c) const { + + return hidden_checkers(c); +} + /// Position::attacks_to() computes a bitboard containing all pieces which /// attacks a given square. There are two versions of this function: One /// which finds attackers of both colors, and one which only finds the @@ -466,7 +444,7 @@ 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 +/// 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. @@ -482,8 +460,14 @@ void Position::find_checkers() { bool Position::pl_move_is_legal(Move m) const { + return pl_move_is_legal(m, pinned_pieces(side_to_move())); +} + +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())); // If we're in check, all pseudo-legal moves are legal, because our // check evasion generator only generates true legal moves. @@ -495,7 +479,6 @@ bool Position::pl_move_is_legal(Move m) const { return true; Color us = side_to_move(); - Color them = opposite_color(us); Square from = move_from(m); Square ksq = king_square(us); @@ -507,6 +490,7 @@ bool Position::pl_move_is_legal(Move m) const { // after the move is made if (move_is_ep(m)) { + Color them = opposite_color(us); Square to = move_to(m); Square capsq = make_square(square_file(to), square_rank(from)); Bitboard b = occupied_squares(); @@ -527,11 +511,12 @@ bool Position::pl_move_is_legal(Move m) const { // If the moving piece is a king, check whether the destination // square is attacked by the opponent. if (from == ksq) - return !(square_is_attacked(move_to(m), them)); + return !(square_is_attacked(move_to(m), 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. - return ( !bit_is_set(pinned_pieces(us), from) + return ( !pinned + || !bit_is_set(pinned, from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } @@ -540,15 +525,21 @@ bool Position::pl_move_is_legal(Move m) const { 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) == piece_of_color_and_type(them, KING)); @@ -561,7 +552,8 @@ bool Position::move_is_check(Move m) const { if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check? return true; - if ( bit_is_set(dcCandidates, from) // Discovered check? + if ( dcCandidates // Discovered check? + && bit_is_set(dcCandidates, from) && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) return true; @@ -600,22 +592,26 @@ bool Position::move_is_check(Move m) const { } return false; + // Test discovered check and normal check according to piece type case KNIGHT: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + return (dcCandidates && bit_is_set(dcCandidates, from)) + || bit_is_set(piece_attacks(ksq), to); case BISHOP: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + return (dcCandidates && bit_is_set(dcCandidates, from)) + || ( direction_between_squares(ksq, to) != DIR_NONE + && bit_is_set(piece_attacks(ksq), to)); case ROOK: - return bit_is_set(dcCandidates, from) // Discovered check? - || bit_is_set(piece_attacks(ksq), to); // Normal check? + return (dcCandidates && bit_is_set(dcCandidates, from)) + || ( direction_between_squares(ksq, to) != DIR_NONE + && bit_is_set(piece_attacks(ksq), to)); case QUEEN: // Discovered checks are impossible! assert(!bit_is_set(dcCandidates, from)); - return bit_is_set(piece_attacks(ksq), to); // Normal check? + return ( direction_between_squares(ksq, to) != DIR_NONE + && bit_is_set(piece_attacks(ksq), to)); case KING: // Discovered check? @@ -669,13 +665,25 @@ bool Position::move_is_capture(Move m) const { } -/// Position::update_checkers() is a private method to udpate chekers info +/// 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) { - if (Piece != KING && bit_is_set(piece_attacks(ksq), to)) + const bool Bishop = (Piece == QUEEN || Piece == BISHOP); + const bool Rook = (Piece == QUEEN || Piece == ROOK); + const bool Slider = Bishop || Rook; + + if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) + || (Rook && bit_is_set(RookPseudoAttacks[ksq], to))) + && bit_is_set(piece_attacks(ksq), to)) // slow, try to early skip + set_bit(pCheckersBB, to); + + else if ( Piece != KING + && !Slider + && bit_is_set(piece_attacks(ksq), to)) set_bit(pCheckersBB, to); if (Piece != QUEEN && bit_is_set(dcCandidates, from)) @@ -695,18 +703,25 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, discovered_check_candidates(side_to_move())); +} + +void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { + assert(is_ok()); assert(move_is_ok(m)); - // Get now the current (pre-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 + // ones which are recalculated from scratch anyway, then switch our state + // pointer to point to the new, ready to be updated, state. + struct ReducedStateInfo { + Key key, pawnKey, materialKey; + int castleRights, rule50; + Square epSquare; + Value mgValue, egValue; + }; - // Copy the old state to our new StateInfo object (except the - // captured piece, which is taken care of later. - // TODO do not copy pinners and checkersBB because are recalculated - // anyway. - newSt = *st; + memcpy(&newSt, st, sizeof(ReducedStateInfo)); newSt.capture = NO_PIECE_TYPE; newSt.previous = st; st = &newSt; @@ -719,10 +734,6 @@ void Position::do_move(Move m, StateInfo& newSt) { // case of non-reversible moves is taken care of later. st->rule50++; - // Reset pinned bitboard and its friends - for (Color c = WHITE; c <= BLACK; c++) - st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB; - if (move_is_castle(m)) do_castle_move(m); else if (move_promotion(m)) @@ -812,12 +823,12 @@ void Position::do_move(Move m, StateInfo& newSt) { Square ksq = king_square(them); switch (piece) { - 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; + case PAWN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KNIGHT: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case BISHOP: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case ROOK: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case QUEEN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KING: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; default: assert(false); break; } } @@ -1199,7 +1210,7 @@ void Position::undo_move(Move m) { if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Replace the captured piece set_bit(&(byColorBB[them]), to); @@ -1221,7 +1232,7 @@ void Position::undo_move(Move m) { board[to] = EMPTY; } - // Finally point out state pointer back to the previous state + // Finally point our state pointer back to the previous state st = st->previous; assert(is_ok()); @@ -1348,7 +1359,7 @@ void Position::undo_promotion_move(Move m) { if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Insert captured piece: set_bit(&(byColorBB[them]), to); @@ -1358,7 +1369,7 @@ void Position::undo_promotion_move(Move m) { // Update material. Because the move is a promotion move, we know // that the captured piece cannot be a pawn. - assert(capture != PAWN); + assert(st->capture != PAWN); npMaterial[them] += piece_value_midgame(st->capture); // Update piece list @@ -1389,7 +1400,7 @@ 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) == piece_of_color_and_type(us, PAWN)); assert(piece_on(from) == EMPTY); @@ -1427,7 +1438,7 @@ 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(StateInfo& newSt) { +void Position::do_null_move(StateInfo& backupSt) { assert(is_ok()); assert(!is_check()); @@ -1435,10 +1446,12 @@ void Position::do_null_move(StateInfo& newSt) { // Back up the information necessary to undo the null move to the supplied // 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. - newSt.lastMove = st->lastMove; - newSt.epSquare = st->epSquare; - newSt.previous = st->previous; - st->previous = &newSt; + // Note that differently from normal case here backupSt is actually used as + // a backup storage not as a new state to be used. + backupSt.lastMove = st->lastMove; + backupSt.epSquare = st->epSquare; + backupSt.previous = st->previous; + st->previous = &backupSt; // Save the current key to the history[] array, in order to be able to // detect repetition draws. @@ -1468,7 +1481,7 @@ void Position::undo_null_move() { assert(is_ok()); assert(!is_check()); - // Restore information from the our StateInfo object + // Restore information from the our backup StateInfo object st->lastMove = st->previous->lastMove; st->epSquare = st->previous->epSquare; st->previous = st->previous->previous; @@ -1490,7 +1503,7 @@ void Position::undo_null_move() { /// 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 +/// 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. @@ -1596,7 +1609,7 @@ 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++) @@ -1639,22 +1652,32 @@ 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; - st->previous = NULL; // We should never dereference this + 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++) { @@ -1664,21 +1687,11 @@ void Position::clear() { pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; } - st->checkersBB = EmptyBoardBB; - for (Color c = WHITE; c <= BLACK; c++) - st->pinners[c] = st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB; - sideToMove = WHITE; gamePly = 0; initialKFile = FILE_E; initialKRFile = FILE_H; initialQRFile = FILE_A; - - st->lastMove = MOVE_NONE; - st->castleRights = NO_CASTLES; - st->epSquare = SQ_NONE; - st->rule50 = 0; - st->previous = NULL; } @@ -1841,15 +1854,14 @@ Value Position::compute_value() const { Value Position::compute_non_pawn_material(Color c) const { Value result = Value(0); - Square s; for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) { Bitboard b = pieces_of_color_and_type(c, pt); - while(b) + while (b) { - s = pop_1st_bit(&b); - assert(piece_on(s) == piece_of_color_and_type(c, pt)); + assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt)); + pop_1st_bit(&b); result += piece_value_midgame(pt); } } @@ -1948,26 +1960,26 @@ bool Position::has_mate_threat(Color c) { void Position::init_zobrist() { - for (int i = 0; i < 2; i++) - for (int j = 0; j < 8; j++) - for (int k = 0; k < 64; k++) - zobrist[i][j][k] = Key(genrand_int64()); + for(Piece p = WP; p <= BK; p++) + for(Square s = SQ_A1; s <= SQ_H8; s++) + zobrist[color_of_piece(p)][type_of_piece(p)][s] = genrand_int64(); - for (int i = 0; i < 64; i++) - zobEp[i] = Key(genrand_int64()); + zobEp[0] = 0ULL; + for(int i = 1; i < 64; i++) + zobEp[i] = genrand_int64(); - for (int i = 0; i < 16; i++) - zobCastle[i] = genrand_int64(); + for(int i = 15; i >= 0; i--) + zobCastle[(i&8) | (i&1) | ((i&2) << 1) | ((i&4) >> 1)] = genrand_int64(); zobSideToMove = genrand_int64(); for (int i = 0; i < 2; i++) for (int j = 0; j < 8; j++) for (int k = 0; k < 16; k++) - zobMaterial[i][j][k] = (k > 0)? Key(genrand_int64()) : Key(0LL); + zobMaterial[i][j][k] = (k > 0)? genrand_int64() : 0LL; for (int i = 0; i < 16; i++) - zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL); + zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = 0ULL; }