X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=c17c5c5757e550680ee9929e144dcbf5bf3f2216;hp=3ae7f50ddae6a99e0c5bb6dbbbefd1ea00e3d84a;hb=190f88e5324ffd048c5234e78b41748432dc7579;hpb=8acb1d7e4ddb9627ed3c2910f6c47f466b94ad90;ds=sidebyside

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;