- squaresToQueen = forward_bb(Us, s);
-
- // If there is an enemy rook or queen attacking the pawn from behind,
- // add all X-ray attacks by the rook or queen. Otherwise consider only
- // the squares in the pawn's path attacked or occupied by the enemy.
- if ( unlikely(forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN))
- && (forward_bb(Them, s) & pos.pieces(Them, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
- unsafeSquares = squaresToQueen;
- else
- unsafeSquares = squaresToQueen & (ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them));
-
- if ( unlikely(forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN))
- && (forward_bb(Them, s) & pos.pieces(Us, ROOK, QUEEN) & pos.attacks_from<ROOK>(s)))
- defendedSquares = squaresToQueen;
- else
- defendedSquares = squaresToQueen & ei.attackedBy[Us][ALL_PIECES];
+ // If there is a rook or queen attacking/defending the pawn from behind,
+ // consider all the squaresToQueen. Otherwise consider only the squares
+ // in the pawn's path attacked or occupied by the enemy.
+ defendedSquares = unsafeSquares = squaresToQueen = forward_bb(Us, s);
+
+ Bitboard bb = forward_bb(Them, s) & pos.pieces(ROOK, QUEEN) & pos.attacks_from<ROOK>(s);
+
+ if (!(pos.pieces(Us) & bb))
+ defendedSquares &= ei.attackedBy[Us][ALL_PIECES];
+
+ if (!(pos.pieces(Them) & bb))
+ unsafeSquares &= ei.attackedBy[Them][ALL_PIECES] | pos.pieces(Them);