X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=841aa0b6c1f06c8dc5886a49d213417de8f47d50;hp=f531010c79de69347b551fd84b8c5187f417619d;hb=70a818cbd6784ccfa8503d94bc31dd1dc16dd1ff;hpb=84f3e867903f62480c33243dd0ecbffd342796fc

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index f531010c..841aa0b6 100644
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -1,6 +1,6 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
-  Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file)
+  Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file)
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -39,6 +39,16 @@ namespace {
   Bitboard BishopTable[0x1480]; // To store bishop attacks
 
   void init_magics(PieceType pt, Bitboard table[], Magic magics[]);
+
+}
+
+
+/// safe_destination() returns the bitboard of target square for the given step
+/// from the given square. If the step is off the board, returns empty bitboard.
+
+inline Bitboard safe_destination(Square s, int step) {
+    Square to = Square(s + step);
+    return is_ok(to) && distance(s, to) <= 2 ? square_bb(to) : Bitboard(0);
 }
 
 
@@ -110,7 +120,7 @@ namespace {
     Direction   RookDirections[4] = {NORTH, SOUTH, EAST, WEST};
     Direction BishopDirections[4] = {NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST};
 
-    for(Direction d : (pt == ROOK ? RookDirections : BishopDirections))
+    for (Direction d : (pt == ROOK ? RookDirections : BishopDirections))
     {
         Square s = sq;
         while(safe_destination(s, d) && !(occupied & s))