template<Color Us, Color Them, Bitboard TRank8BB, Bitboard TRank3BB, SquareDelta TDELTA_N>
MoveStack* do_generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist)
{
- // 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.
- Bitboard empty = pos.empty_squares();
-
// Find all friendly pawns not on the enemy king's file
- Bitboard b1 = pos.pawns(Us) & ~file_bb(ksq), b2, b3;
+ Bitboard b1, b2, b3;
+ Bitboard empty = pos.empty_squares();
- // Discovered checks, single pawn pushes, no promotions
- b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & empty & ~TRank8BB;
- while (b3)
+ if (dc != EmptyBoardBB)
{
- Square to = pop_1st_bit(&b3);
- (*mlist++).move = make_move(to - TDELTA_N, to);
- }
+ // 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 = pos.pawns(Us) & ~file_bb(ksq);
+
+ // Discovered checks, single pawn pushes, no promotions
+ b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & empty & ~TRank8BB;
+ while (b3)
+ {
+ Square to = pop_1st_bit(&b3);
+ (*mlist++).move = make_move(to - TDELTA_N, to);
+ }
- // Discovered checks, double pawn pushes
- b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty;
- while (b3)
- {
- Square to = pop_1st_bit(&b3);
- (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to);
+ // Discovered checks, double pawn pushes
+ b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty;
+ while (b3)
+ {
+ Square to = pop_1st_bit(&b3);
+ (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to);
+ }
}
// Direct checks. These are possible only for pawns on neighboring files
- // of the enemy king
- b1 &= (~dc & neighboring_files_bb(ksq));
+ // of the enemy king.
+ b1 = pos.pawns(Us) & neighboring_files_bb(ksq) & ~dc;
// Direct checks, single pawn pushes
b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & empty;
b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8)
& empty
& pos.pawn_attacks(Them, ksq);
-
while (b3)
{
Square to = pop_1st_bit(&b3);