X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=67680b1fbac52c46360109abdabbd6bcf585863a;hp=0a275b5ee3bdc4e7dfb48fe3b8e8d2f835cced48;hb=c02613860a3836bb85da25ae2fed9f1351ba27a5;hpb=962216440c186d067d8946112acab847ccb7249f diff --git a/src/position.cpp b/src/position.cpp index 0a275b5e..67680b1f 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -207,7 +207,6 @@ void Position::from_fen(const std::string& fen) { castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; find_checkers(); - find_pinned(); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -321,6 +320,29 @@ 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 { + + Bitboard p; + Square ksq = king_square(c); + return hidden_checks(c, ksq, p) | hidden_checks(c, ksq, p); +} + + +/// 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 { + + Bitboard p; + Square ksq = king_square(opposite_color(c)); + return hidden_checks(c, ksq, p) | hidden_checks(c, ksq, p); +} + + /// 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 @@ -447,31 +469,18 @@ void Position::find_checkers() { } -/// Position:find_pinned() computes the pinned, pinners and dcCandidates -/// bitboards for both colors. Bitboard checkersBB must be already updated. - -void Position::find_pinned() { +/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal - Bitboard p1, p2; - Square ksq; +bool Position::pl_move_is_legal(Move m) const { - for (Color c = WHITE; c <= BLACK; c++) - { - ksq = king_square(c); - st->pinned[c] = hidden_checks(c, ksq, p1) | hidden_checks(c, ksq, p2); - st->pinners[c] = p1 | p2; - ksq = king_square(opposite_color(c)); - st->dcCandidates[c] = hidden_checks(c, ksq, p1) | hidden_checks(c, ksq, p2); - } + return pl_move_is_legal(m, pinned_pieces(side_to_move())); } - -/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal - -bool Position::pl_move_is_legal(Move m) const { +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. @@ -519,7 +528,7 @@ bool Position::pl_move_is_legal(Move m) 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_pieces(us), from) + return ( !bit_is_set(pinned, from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } @@ -528,15 +537,21 @@ 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)); @@ -657,7 +672,8 @@ 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, @@ -677,42 +693,26 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square } -/// Position::init_new_state() copies from the current state the fields -/// that will be updated incrementally, skips the fields, like bitboards -/// that will be recalculated form scratch anyway. - -void Position::init_new_state(StateInfo& newSt) { - - newSt.key = st->key; - newSt.pawnKey = st->pawnKey; - newSt.materialKey = st->materialKey; - newSt.castleRights = st->castleRights; - newSt.rule50 = st->rule50; - newSt.epSquare = st->epSquare; - newSt.mgValue = st->mgValue; - newSt.egValue = st->egValue; - newSt.capture = NO_PIECE_TYPE; - newSt.previous = st; -} - - /// 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) { + 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 (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. - init_new_state(newSt); + 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 @@ -812,18 +812,17 @@ 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; } } // Finish - find_pinned(); st->key ^= zobSideToMove; sideToMove = opposite_color(sideToMove); gamePly++; @@ -1528,11 +1527,6 @@ int Position::see(Square from, Square to) const { 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); @@ -1565,17 +1559,6 @@ int Position::see(Square from, Square to) const { | (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; @@ -1638,12 +1621,6 @@ 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))) { @@ -1662,6 +1639,18 @@ 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.