}
-/// generate_legal_moves() computes a complete list of legal moves in the
-/// current position. This function is not very fast, and should be used
-/// only in situations where performance is unimportant. It wouldn't be
-/// very hard to write an efficient legal move generator, but for the moment
-/// we don't need it.
+/// 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_legal_moves(const Position& pos, MoveStack* mlist) {
+MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
assert(pos.is_ok());
// 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++)
/// move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and a pinned pieces bitboard as input, and tests whether
-/// the move is legal. If the move is legal, the move itself is
-/// returned. If not, the function returns false. This function must
-/// only be used when the side to move is not in check.
+/// 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(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);
Color them = opposite_color(us);
Square to = move_to(m);
- // En passant moves
- if (move_is_ep(m))
- {
- // The piece must be a pawn and destination square must be the
- // en passant square.
- if ( type_of_piece(pc) != PAWN
- || to != pos.ep_square())
- return false;
-
- assert(pos.square_is_empty(to));
- assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN));
-
- // The move is pseudo-legal, check if it is also legal
- return pos.pl_move_is_legal(m, pinned);
- }
-
- // Castling moves
- if (move_is_short_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_kingside(us))
- return false;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_kr_square(us));
- assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK));
-
- Square g1 = relative_square(us, SQ_G1);
- Square f1 = relative_square(us, SQ_F1);
- Square s;
- bool illegal = false;
-
- // Check if any of the squares between king and rook
- // is occupied or under attack.
- for (s = Min(from, g1); s <= Max(from, g1); s++)
- if ( (s != from && s != to && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
-
- // Check if any of the squares between king and rook
- // is occupied.
- for (s = Min(to, f1); s <= Max(to, f1); s++)
- if (s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- return !illegal;
- }
-
- if (move_is_long_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_queenside(us))
- return false;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_qr_square(us));
- assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK));
-
- Square c1 = relative_square(us, SQ_C1);
- Square d1 = relative_square(us, SQ_D1);
- Square s;
- bool illegal = false;
-
- for (s = Min(from, c1); s <= Max(from, c1); s++)
- if( (s != from && s != to && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
-
- for (s = Min(to, d1); s <= Max(to, d1); s++)
- if(s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- if ( square_file(to) == FILE_B
- && ( pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, ROOK)
- || pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, QUEEN)))
- illegal = true;
-
- return !illegal;
- }
-
- // Normal moves
-
// The destination square cannot be occupied by a friendly piece
if (pos.color_of_piece_on(to) == us)
return false;
}
-/// Another version of move_is_legal(), which takes only a position and a move
-/// as input. This function does not require that the side to move is not in
-/// check. It is not optimized for speed, and is only used for verifying move
-/// legality when building a PV from the transposition table.
-
-bool move_is_legal(const Position& pos, const Move m) {
-
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
- if (!pos.is_check())
- return move_is_legal(pos, m, pinned);
- else
- {
- Position p(pos);
- MoveStack mlist[64];
- MoveStack* last = generate_evasions(p, mlist, pinned);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return true;
-
- return false;
- }
-}
-
-
namespace {
template<PieceType Piece>