- enum CastlingSide {
- KING_SIDE,
- QUEEN_SIDE
- };
-
- enum MoveType {
- CAPTURE,
- NON_CAPTURE,
- CHECK,
- EVASION
- };
-
- // Helper templates
- template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position&, MoveStack*);
-
- template<Color Us, MoveType Type>
- MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard = EmptyBoardBB,
- Square = SQ_NONE, Bitboard = EmptyBoardBB);
-
- // Template generate_piece_moves (captures and non-captures) with specializations and overloads
- template<PieceType>
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
-
- template<>
- MoveStack* generate_piece_moves<KING>(const Position&, MoveStack*, Color, Bitboard);
-
- template<PieceType Piece, MoveType Type>
- inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us) {
-
- assert(Piece == PAWN);
- assert(Type == CAPTURE || Type == NON_CAPTURE);
-
- return (us == WHITE ? generate_pawn_moves<WHITE, Type>(p, m)
- : generate_pawn_moves<BLACK, Type>(p, m));
- }
-
- // Templates for non-capture checks generation
-
- template<PieceType Piece>
- MoveStack* generate_discovered_checks(const Position& pos, Square from, MoveStack* mlist);
-
- template<PieceType>
- MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square);
-
- template<>
- inline MoveStack* generate_direct_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
-
- return (us == WHITE ? generate_pawn_moves<WHITE, CHECK>(p, m, dc, ksq)
- : generate_pawn_moves<BLACK, CHECK>(p, m, dc, ksq));
- }
-
- // Template generate_piece_evasions with specializations
- template<PieceType>
- MoveStack* generate_piece_evasions(const Position&, MoveStack*, Color, Bitboard, Bitboard);
-
- template<>
- inline MoveStack* generate_piece_evasions<PAWN>(const Position& p, MoveStack* m,
- Color us, Bitboard t, Bitboard pnd) {
-
- return (us == WHITE ? generate_pawn_moves<WHITE, EVASION>(p, m, pnd, SQ_NONE, t)
- : generate_pawn_moves<BLACK, EVASION>(p, m, pnd, SQ_NONE, t));
- }
-}
-
-
-////
-//// Functions
-////
-
-
-/// generate_captures() generates all pseudo-legal captures and queen
-/// promotions. Returns a pointer to the end of the move list.
-
-MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
-
- Color us = pos.side_to_move();
- Bitboard target = pos.pieces_of_color(opposite_color(us));
-
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<PAWN, CAPTURE>(pos, mlist, us);
- return generate_piece_moves<KING>(pos, mlist, us, target);
-}
-
-
-/// generate_noncaptures() generates all pseudo-legal non-captures and
-/// underpromotions. Returns a pointer to the end of the move list.
-
-MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
-
- Color us = pos.side_to_move();
- Bitboard target = pos.empty_squares();
-
- mlist = generate_piece_moves<PAWN, NON_CAPTURE>(pos, mlist, us);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
- mlist = generate_piece_moves<KING>(pos, mlist, us, target);
- mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
- return generate_castle_moves<QUEEN_SIDE>(pos, mlist);
-}
-
-
-/// generate_non_capture_checks() generates all pseudo-legal non-captures and
-/// underpromotions that give check. Returns a pointer to the end of the move list.
-
-MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
-
- Color us = pos.side_to_move();
- Square ksq = pos.king_square(opposite_color(us));
-
- assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
-
- // Discovered non-capture checks
- Bitboard b = dc;
- while (b)
- {
- Square from = pop_1st_bit(&b);
- switch (pos.type_of_piece_on(from))
- {
- case PAWN: /* Will be generated togheter with pawns direct checks */ break;
- case KNIGHT: mlist = generate_discovered_checks<KNIGHT>(pos, from, mlist); break;
- case BISHOP: mlist = generate_discovered_checks<BISHOP>(pos, from, mlist); break;
- case ROOK: mlist = generate_discovered_checks<ROOK>(pos, from, mlist); break;
- case KING: mlist = generate_discovered_checks<KING>(pos, from, mlist); break;
- default: assert(false); break;
- }
- }
-
- // Direct non-capture checks
- mlist = generate_direct_checks<PAWN>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<KNIGHT>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<BISHOP>(pos, mlist, us, dc, ksq);
- mlist = generate_direct_checks<ROOK>(pos, mlist, us, dc, ksq);
- return generate_direct_checks<QUEEN>(pos, mlist, us, dc, ksq);
-}
-
-
-/// generate_evasions() generates all pseudo-legal check evasions when
-/// the side to move is in check. Returns a pointer to the end of the move list.
-
-MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
-
- assert(pos.is_ok());
- assert(pos.is_check());
-
- Bitboard b;
- Square from, to, checksq;
- int checkersCnt = 0;
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
- Bitboard checkers = pos.checkers();
- Bitboard sliderAttacks = EmptyBoardBB;
-
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
- assert(checkers);
-
- // Find squares attacked by slider checkers, we will remove
- // them from the king evasions set so to early skip known
- // illegal moves and avoid an useless legality check later.
- b = checkers;
- do
- {
- checkersCnt++;
- checksq = pop_1st_bit(&b);
-
- assert(pos.color_of_piece_on(checksq) == them);
-
- switch (pos.type_of_piece_on(checksq))
- {
- case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break;
- case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break;
- case QUEEN:
- // In case of a queen remove also squares attacked in the other direction to
- // avoid possible illegal moves when queen and king are on adjacent squares.
- if (direction_is_straight(checksq, ksq))
- sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from<BISHOP>(checksq);
- else
- sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from<ROOK>(checksq);
- default:
- break;
- }
- } while (b);
-
- // Generate evasions for king, capture and non capture moves
- b = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
- from = ksq;
- SERIALIZE_MOVES(b);
-
- // Generate evasions for other pieces only if not double check
- if (checkersCnt > 1)
- return mlist;
-
- Bitboard target = squares_between(checksq, ksq);
-
- // Pawn captures
- b = pos.attacks_from<PAWN>(checksq, them) & pos.pieces(PAWN, us) & ~pinned;
- while (b)
- {
- from = pop_1st_bit(&b);
- if (relative_rank(us, checksq) == RANK_8)
- {
- (*mlist++).move = make_promotion_move(from, checksq, QUEEN);
- (*mlist++).move = make_promotion_move(from, checksq, ROOK);
- (*mlist++).move = make_promotion_move(from, checksq, BISHOP);
- (*mlist++).move = make_promotion_move(from, checksq, KNIGHT);
- } else
- (*mlist++).move = make_move(from, checksq);
- }
-
- // Pawn blocking evasions (possible only if the checking piece is a slider)
- if (sliderAttacks)
- mlist = generate_piece_evasions<PAWN>(pos, mlist, us, target, pinned);
-
- // Add the checking piece to the target squares
- target |= checkers;
-
- // Captures and blocking evasions for the other pieces
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
-
- // Finally, the special case of en passant captures. An en passant
- // capture can only be a check evasion if the check is not a discovered
- // check. If pos.ep_square() is set, the last move made must have been
- // a double pawn push. If, furthermore, the checking piece is a pawn,
- // an en passant check evasion may be possible.
- if (pos.ep_square() != SQ_NONE && (checkers & pos.pieces(PAWN, them)))
- {
- to = pos.ep_square();
- b = pos.attacks_from<PAWN>(to, them) & pos.pieces(PAWN, us);
-
- // The checking pawn cannot be a discovered (bishop) check candidate
- // otherwise we were in check also before last double push move.
- assert(!bit_is_set(pos.discovered_check_candidates(them), checksq));
- assert(count_1s(b) == 1 || count_1s(b) == 2);
-
- b &= ~pinned;
- while (b)
- {
- from = pop_1st_bit(&b);
- // Move is always legal because checking pawn is not a discovered
- // check candidate and our capturing pawn has been already tested
- // against pinned pieces.
- (*mlist++).move = make_ep_move(from, to);
- }
- }
- return mlist;
-}
-
-
-/// generate_moves() computes a complete list of legal or pseudo-legal moves in
-/// the current position. This function is not very fast, and should be used
-/// only in non time-critical paths.
-
-MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
-
- assert(pos.is_ok());
-
- MoveStack* last;
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
-
- // Generate pseudo-legal moves
- if (pos.is_check())
- last = generate_evasions(pos, mlist, pinned);
- else {
- last = generate_captures(pos, mlist);
- last = generate_noncaptures(pos, last);
- }
- if (pseudoLegal)
- return last;
-
- // Remove illegal moves from the list
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (!pos.pl_move_is_legal(cur->move, pinned))
- {
- cur->move = (--last)->move;
- cur--;
- }
- return last;
-}
-
-
-/// move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and tests whether the move is legal. This version is not very fast
-/// and should be used only in non time-critical paths.
-
-bool move_is_legal(const Position& pos, const Move m) {
-
- MoveStack mlist[256];
- MoveStack* last = generate_moves(pos, mlist, true);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return pos.pl_move_is_legal(m);
-
- return false;
-}
-
-
-/// Fast version of move_is_legal() that takes a position a move and a
-/// bitboard of pinned pieces as input, and tests whether the move is legal.
-/// This version must only be used when the side to move is not in check.