X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=e6125ec7c2c756816bc098014d132fa04900ae03;hp=7725b934e1eb34824789ae7cbdeaf54078ab53fb;hb=9b6b9e67fe767a83837ff4cbf3954a8cf70eee59;hpb=55f9afee2a079b2dd0b1aeda41082c58eb317ca3 diff --git a/src/position.cpp b/src/position.cpp index 7725b934..e6125ec7 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -207,7 +207,7 @@ void Position::from_fen(const std::string& fen) { castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO; find_checkers(); - find_pinned(); + find_hidden_checks(); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -446,23 +446,29 @@ void Position::find_checkers() { 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. -/// Position:find_pinned() computes the pinned, pinners and dcCandidates -/// bitboards for both colors. Bitboard checkersBB must be already updated. - -void Position::find_pinned() { +void Position::find_hidden_checks(Color us, unsigned int types) { Bitboard p1, p2; - Square ksq; - - for (Color c = WHITE; c <= BLACK; c++) + Color them = opposite_color(us); + Square ksq = king_square(them); + if (types & Pinned) { - 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); + st->pinned[them] = hidden_checks(them, ksq, p1) | hidden_checks(them, ksq, p2); + st->pinners[them] = p1 | p2; } + if (types & DcCandidates) + st->dcCandidates[us] = hidden_checks(us, ksq, p1) | hidden_checks(us, ksq, p2); +} + +void Position::find_hidden_checks() { + + for (Color c = WHITE; c <= BLACK; c++) + find_hidden_checks(c, Pinned | DcCandidates); } @@ -657,7 +663,8 @@ 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, @@ -677,22 +684,72 @@ 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. +/// 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(). + +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] || bit_is_set(st->pinners[them], from)) && (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]))) + { + // If the move gives direct check and we don't have pinners/dc cadidates + // then we can be sure that we won't have them also after the move if + // we are not moving from a possible king attack direction. + bool outsideChecker = false; -void Position::init_new_state(StateInfo& newSt) { + if ( bit_is_set(st->checkersBB, to) + && !(bit_is_set(RookPseudoAttacks[ksq], from) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq]))) + && !(bit_is_set(BishopPseudoAttacks[ksq], from) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq])))) + outsideChecker = true; - 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; + if (!outsideChecker || st->pinned[them]) + find_hidden_checks(us, Pinned); + + if (!outsideChecker || st->dcCandidates[us] || bit_is_set(st->pinned[them], to)) + find_hidden_checks(us, DcCandidates); + } + + ksq = king_square(us); + + if (ksq == to) + { + find_hidden_checks(them, Pinned | DcCandidates); + return; + } + + // It is possible that we have captured an opponent hidden checker? + Bitboard checkerCaptured = st->capture && (st->dcCandidates[them] || bit_is_set(st->pinners[us], to)); + + // 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, Pinned); + + // If we don't have opponent dc candidates and we are moving in the + // attack line then won't be any dc candidates also after the move. + if ( st->dcCandidates[them] + || (bit_is_set(RookPseudoAttacks[ksq], from) && (rooks_and_queens(them) & RookPseudoAttacks[ksq])) + || (bit_is_set(BishopPseudoAttacks[ksq], from) && (bishops_and_queens(them) & BishopPseudoAttacks[ksq]))) + find_hidden_checks(them, DcCandidates); + } } @@ -712,7 +769,9 @@ void Position::do_move(Move m, StateInfo& newSt) { // 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 @@ -820,10 +879,11 @@ void Position::do_move(Move m, StateInfo& newSt) { case KING: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; default: assert(false); break; } + + update_hidden_checks(from, to); } // Finish - find_pinned(); st->key ^= zobSideToMove; sideToMove = opposite_color(sideToMove); gamePly++; @@ -972,6 +1032,9 @@ void Position::do_castle_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); } @@ -1062,6 +1125,9 @@ void Position::do_promotion_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); } @@ -1144,6 +1210,9 @@ void Position::do_ep_move(Move m) { // Update checkers BB st->checkersBB = attacks_to(king_square(them), us); + + // Update hidden checks + find_hidden_checks(); }