-////
-//// 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-capturing,
-/// non-promoting checks. 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));
-
- // 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 mlist;
-}
-
-
-/// generate_evasions() generates all check evasions when the side to move is
-/// in check. Unlike the other move generation functions, this one generates
-/// only legal moves. 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());
-
- Square from, to;
- Color us = pos.side_to_move();
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
- Bitboard sliderAttacks = EmptyBoardBB;
- Bitboard checkers = pos.checkers();
-
- assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
-
- // The bitboard of occupied pieces without our king
- Bitboard b_noKing = pos.occupied_squares();
- clear_bit(&b_noKing, ksq);
-
- // Find squares attacked by slider checkers, we will
- // remove them from king evasions set so to avoid a couple
- // of cycles in the slow king evasions legality check loop
- // and to be able to use attackers_to().
- Bitboard b = checkers & pos.pieces(BISHOP, QUEEN);
- while (b)
- {
- from = pop_1st_bit(&b);
- sliderAttacks |= bishop_attacks_bb(from, b_noKing);
- }
-
- b = checkers & pos.pieces(ROOK, QUEEN);
- while (b)
- {
- from = pop_1st_bit(&b);
- sliderAttacks |= rook_attacks_bb(from, b_noKing);
- }
-
- // Generate evasions for king, both captures and non captures
- Bitboard b1 = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
- Bitboard enemy = pos.pieces_of_color(them);
- while (b1)
- {
- to = pop_1st_bit(&b1);
- // Note that we can use attackers_to() only because we
- // have already removed slider checkers attacked squares.
- if (!(pos.attackers_to(to) & enemy))
- (*mlist++).move = make_move(ksq, to);
- }
-
- // Generate evasions for other pieces only if not double check. We use a
- // simple bit twiddling hack here rather than calling count_1s in order to
- // save some time (we know that pos.checkers() has at most two nonzero bits).
- if (!(checkers & (checkers - 1))) // Only one bit set?
- {
- Square checksq = first_1(checkers);
-
- assert(pos.color_of_piece_on(checksq) == them);
-
- // Generate captures of the checking piece
-
- // Pawn captures
- b1 = pos.attacks_from<PAWN>(checksq, them) & pos.pieces(PAWN, us) & ~pinned;
- while (b1)
- {
- from = pop_1st_bit(&b1);
- 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);
- }
-
- // Pieces captures
- b1 = ( (pos.attacks_from<KNIGHT>(checksq) & pos.pieces(KNIGHT, us))
- | (pos.attacks_from<BISHOP>(checksq) & pos.pieces(BISHOP, QUEEN, us))
- | (pos.attacks_from<ROOK>(checksq) & pos.pieces(ROOK, QUEEN, us)) ) & ~pinned;
-
- while (b1)
- {
- from = pop_1st_bit(&b1);
- (*mlist++).move = make_move(from, checksq);
- }
-
- // Blocking check evasions are possible only if the checking piece is a slider
- if (sliderAttacks)
- {
- Bitboard blockSquares = squares_between(checksq, ksq);
-
- assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
-
- if (blockSquares)
- {
- mlist = generate_piece_moves<PAWN>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_moves<BISHOP>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_moves<ROOK>(pos, mlist, us, blockSquares, pinned);
- mlist = generate_piece_moves<QUEEN>(pos, mlist, us, blockSquares, pinned);
- }
- }
-
- // 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();
- b1 = 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(b1) == 1 || count_1s(b1) == 2);
-
- b1 &= ~pinned;
- while (b1)
- {
- from = pop_1st_bit(&b1);
- // 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 situations where performance is unimportant.
-
-MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
-
- assert(pos.is_ok());
-
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
-
- if (pos.is_check())
- return generate_evasions(pos, mlist, pinned);
-
- // Generate pseudo-legal moves
- MoveStack* 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 for 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 pinned pieces bitboard as input, and tests whether the move is legal.
-/// This version must only be used when the side to move is not in check.
-
-bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
-
- assert(pos.is_ok());
- assert(!pos.is_check());
- assert(move_is_ok(m));
- assert(pinned == pos.pinned_pieces(pos.side_to_move()));
-
- // Use a slower but simpler function for uncommon cases
- if (move_is_ep(m) || move_is_castle(m))
- return move_is_legal(pos, m);
-
- Color us = pos.side_to_move();
- Square from = move_from(m);
- Piece pc = pos.piece_on(from);