/// generate_captures generates() all pseudo-legal captures and queen
-/// promotions. The return value is the number of moves generated.
+/// promotions. The return value is the number of moves generated.
int generate_captures(const Position& pos, MoveStack* mlist) {
// Direct checks. These are possible only for pawns on neighboring files
// and in the two ranks that, after the push, are in front of the enemy king.
b1 = pawns & neighboring_files_bb(ksq) & ~dc;
- b2 = rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S);
- b1 &= b2;
- if (!b1)
+
+ // We can get false positives if (ksq + x) is not in [0,63] range but
+ // is not a problem, they will be filtered out later.
+ b2 = b1 & (rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S));
+ if (!b2)
return mlist;
// Direct checks, single pawn pushes