+ template<Color Us>
+ MoveStack* generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist)
+ {
+ // Calculate our parametrized parameters at compile time
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+ const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
+ const SquareDelta TDELTA_S = (Us == WHITE ? DELTA_S : DELTA_N);
+
+ Square to;
+ Bitboard b1, b2, b3;
+ Bitboard pawns = pos.pawns(Us);
+
+ if (dc & pawns)
+ {
+ Bitboard empty = pos.empty_squares();
+
+ // Pawn moves which gives discovered check. This is possible only if the
+ // pawn is not on the same file as the enemy king, because we don't
+ // generate captures.
+ b1 = pawns & ~file_bb(ksq);
+
+ // Discovered checks, single pawn pushes, no promotions
+ b2 = b3 = move_pawns<Us, DELTA_N>(b1 & dc) & empty & ~TRank8BB;
+ SERIALIZE_MOVES_D(b3, -TDELTA_N);
+
+ // Discovered checks, double pawn pushes
+ b3 = move_pawns<Us, DELTA_N>(b2 & TRank3BB) & empty;
+ SERIALIZE_MOVES_D(b3, -TDELTA_N -TDELTA_N);
+ }
+
+ // 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;
+
+ // 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
+ Bitboard empty = pos.empty_squares();
+ b2 = move_pawns<Us, DELTA_N>(b1) & empty;
+ b3 = b2 & pos.pawn_attacks(Them, ksq);
+ SERIALIZE_MOVES_D(b3, -TDELTA_N);
+
+ // Direct checks, double pawn pushes
+ b3 = move_pawns<Us, DELTA_N>(b2 & TRank3BB) & empty & pos.pawn_attacks(Them, ksq);
+ SERIALIZE_MOVES_D(b3, -TDELTA_N -TDELTA_N);
+ return mlist;
+ }