Introduce single_bit() helper

[stockfish] / src / position.cpp

diff --git a/src/position.cpp b/src/position.cpp
index bf415b34d22ac48485e9b6cc24dd1d5928fb8fdc..b10ea9ea49c787bab1b08670917505cb3cb5023e 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -242,14 +242,27 @@ void Position::from_fen(const string& fenStr, bool isChess960) {
 /// Position::set_castle_right() is an helper function used to set castling
 /// rights given the corresponding color and the rook starting square.
 
-void Position::set_castle_right(Color c, Square rsq) {
+void Position::set_castle_right(Color c, Square rfrom) {
 
-  int f = (rsq < king_square(c) ? WHITE_OOO : WHITE_OO) << c;
+  Square kfrom = king_square(c);
+  bool kingSide = kfrom < rfrom;
+  int cr = (kingSide ? WHITE_OO : WHITE_OOO) << c;
 
-  st->castleRights |= f;
-  castleRightsMask[king_square(c)] |= f;
-  castleRightsMask[rsq] |= f;
-  castleRookSquare[f] = rsq;
+  st->castleRights |= cr;
+  castleRightsMask[kfrom] |= cr;
+  castleRightsMask[rfrom] |= cr;
+  castleRookSquare[cr] = rfrom;
+
+  Square kto = relative_square(c, kingSide ? SQ_G1 : SQ_C1);
+  Square rto = relative_square(c, kingSide ? SQ_F1 : SQ_D1);
+
+  for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++)
+      if (s != kfrom && s != rfrom)
+          castlePath[cr] |= s;
+
+  for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++)
+      if (s != kfrom && s != rfrom)
+          castlePath[cr] |= s;
 }
 
 
@@ -366,8 +379,7 @@ Bitboard Position::hidden_checkers() const {
   {
       b = squares_between(ksq, pop_1st_bit(&pinners)) & occupied_squares();
 
-      // Only one bit set and is an our piece?
-      if (b && !(b & (b - 1)) && (b & pieces(sideToMove)))
+      if (b && single_bit(b) && (b & pieces(sideToMove)))
           result |= b;
   }
   return result;
@@ -1507,7 +1519,7 @@ void Position::init() {
       Bitboard b = cr;
       while (b)
       {
-          Key k = zobCastle[1 << pop_1st_bit(&b)];
+          Key k = zobCastle[1ULL << pop_1st_bit(&b)];
           zobCastle[cr] ^= k ? k : rk.rand<Key>();
       }
   }