- Color us, them;
- Square ksq, from, to;
- Bitboard empty, checkSqs, b1, b2, b3;
- int n = 0;
-
- us = pos.side_to_move();
- them = opposite_color(us);
-
- ksq = pos.king_square(them);
- assert(pos.piece_on(ksq) == king_of_color(them));
-
- dc = pos.discovered_check_candidates(us);
- empty = pos.empty_squares();
-
- // Pawn moves. This is somewhat messy, and we use separate code for white
- // and black, because we can't shift by negative numbers in C/C++. :-(
-
- if (us == WHITE)
- {
- // Pawn moves which give 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.
-
- // Find all friendly pawns not on the enemy king's file:
- b1 = pos.pawns(us) & ~file_bb(ksq);
-
- // Discovered checks, single pawn pushes:
- b2 = b3 = ((b1 & dc) << 8) & ~Rank8BB & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_N, to);
- }
-
- // Discovered checks, double pawn pushes:
- b3 = ((b2 & Rank3BB) << 8) & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
- }
-
- // Direct checks. These are possible only for pawns on neighboring files
- // of the enemy king:
-
- b1 &= (~dc & neighboring_files_bb(ksq));
-
- // Direct checks, single pawn pushes:
- b2 = (b1 << 8) & empty;
- b3 = b2 & pos.black_pawn_attacks(ksq);
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_N, to);
- }
-
- // Direct checks, double pawn pushes:
- b3 = ((b2 & Rank3BB) << 8) & empty & pos.black_pawn_attacks(ksq);
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
- }
- }
- else { // (us == BLACK)
-
- // Pawn moves which give 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.
-
- // Find all friendly pawns not on the enemy king's file:
- b1 = pos.pawns(us) & ~file_bb(ksq);
-
- // Discovered checks, single pawn pushes:
- b2 = b3 = ((b1 & dc) >> 8) & ~Rank1BB & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_S, to);
- }
-
- // Discovered checks, double pawn pushes:
- b3 = ((b2 & Rank6BB) >> 8) & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
- }
-
- // Direct checks. These are possible only for pawns on neighboring files
- // of the enemy king:
-
- b1 &= (~dc & neighboring_files_bb(ksq));
-
- // Direct checks, single pawn pushes:
- b2 = (b1 >> 8) & empty;
- b3 = b2 & pos.white_pawn_attacks(ksq);
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_S, to);
- }
-
- // Direct checks, double pawn pushes:
- b3 = ((b2 & Rank6BB) >> 8) & empty & pos.black_pawn_attacks(ksq);
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
- }
- }
-
- // Knight moves
- b1 = pos.knights(us);
- if(b1) {
- // Discovered knight checks:
- b2 = b1 & dc;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.knight_attacks(from) & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
-
- // Direct knight checks:
- b2 = b1 & ~dc;
- checkSqs = pos.knight_attacks(ksq) & empty;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.knight_attacks(from) & checkSqs;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
- }
-
- // Bishop moves
- b1 = pos.bishops(us);
- if(b1) {
- // Discovered bishop checks:
- b2 = b1 & dc;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.bishop_attacks(from) & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
-
- // Direct bishop checks:
- b2 = b1 & ~dc;
- checkSqs = pos.bishop_attacks(ksq) & empty;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.bishop_attacks(from) & checkSqs;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
- }
-
- // Rook moves
- b1 = pos.rooks(us);
- if(b1) {
- // Discovered rook checks:
- b2 = b1 & dc;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.rook_attacks(from) & empty;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
-
- // Direct rook checks:
- b2 = b1 & ~dc;
- checkSqs = pos.rook_attacks(ksq) & empty;
- while(b2) {
- from = pop_1st_bit(&b2);
- b3 = pos.rook_attacks(from) & checkSqs;
- while(b3) {
- to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(from, to);
- }
- }
- }
-
- // Queen moves
- b1 = pos.queens(us);
- if(b1) {
- // Discovered queen checks are impossible!
-
- // Direct queen checks:
- checkSqs = pos.queen_attacks(ksq) & empty;
- while(b1) {
- from = pop_1st_bit(&b1);
- b2 = pos.queen_attacks(from) & checkSqs;
- while(b2) {
- to = pop_1st_bit(&b2);
- mlist[n++].move = make_move(from, to);
- }
- }
- }
-
- // King moves
- from = pos.king_square(us);
- if(bit_is_set(dc, from)) {
- b1 = pos.king_attacks(from) & empty & ~QueenPseudoAttacks[ksq];
- while(b1) {
- to = pop_1st_bit(&b1);
- mlist[n++].move = make_move(from, to);
- }
- }
-
- // TODO: Castling moves!
-
- return n;
+ Color us = pos.side_to_move();
+ Square ksq = pos.king_square(opposite_color(us));
+ MoveStack* mlist_start = mlist;
+
+ assert(pos.piece_on(ksq) == king_of_color(opposite_color(us)));
+
+ // Pieces moves
+ mlist = generate_piece_checks<PAWN>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<KNIGHT>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<BISHOP>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<ROOK>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<QUEEN>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<KING>(pos, mlist, us, dc, ksq);
+
+ // Castling moves that give check. Very rare but nice to have!
+ if ( pos.can_castle_queenside(us)
+ && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_D)
+ && castling_is_check(pos, QUEEN_SIDE))
+ mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist);
+
+ if ( pos.can_castle_kingside(us)
+ && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_F)
+ && castling_is_check(pos, KING_SIDE))
+ mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
+
+ return int(mlist - mlist_start);