diff --git a/src/position.cpp b/src/position.cpp index 3ae7f50d..c17c5c57 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -796,11 +796,14 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { pieceList[us][piece][index[from]] = to; index[to] = index[from]; - // Update castle rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[from]; - st->castleRights &= castleRightsMask[to]; - st->key ^= zobCastle[st->castleRights]; + // Update castle rights, try to shortcut a common case + if ((castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES) + { + st->key ^= zobCastle[st->castleRights]; + st->castleRights &= castleRightsMask[from]; + st->castleRights &= castleRightsMask[to]; + st->key ^= zobCastle[st->castleRights]; + } // Update checkers bitboard, piece must be already moved st->checkersBB = EmptyBoardBB;