const CastleRight CR[] = { Side ? WHITE_OOO : WHITE_OO,
Side ? BLACK_OOO : BLACK_OO };
- if (!pos.can_castle(CR[us]))
+ if (pos.castle_impeded(CR[us]) || !pos.can_castle(CR[us]))
return mlist;
// After castling, the rook and king final positions are the same in Chess960
Square kfrom = pos.king_square(us);
Square rfrom = pos.castle_rook_square(CR[us]);
Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
- Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
Bitboard enemies = pos.pieces(~us);
assert(!pos.in_check());
assert(pos.piece_on(kfrom) == make_piece(us, KING));
assert(pos.piece_on(rfrom) == make_piece(us, ROOK));
- // Unimpeded rule: All the squares between the king's initial and final squares
- // (including the final square), and all the squares between the rook's initial
- // and final squares (including the final square), must be vacant except for
- // the king and castling rook.
- for (Square s = std::min(rfrom, rto), e = std::max(rfrom, rto); s <= e; s++)
- if (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- return mlist;
-
for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++)
- if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & enemies))
+ if ( s != kfrom // We are not in check
+ && (pos.attackers_to(s) & enemies))
return mlist;
// Because we generate only legal castling moves we need to verify that
/// Position::set_castle_right() is an helper function used to set castling
/// rights given the corresponding color and the rook starting square.
-void Position::set_castle_right(Color c, Square rsq) {
+void Position::set_castle_right(Color c, Square rfrom) {
- int f = (rsq < king_square(c) ? WHITE_OOO : WHITE_OO) << c;
+ Square kfrom = king_square(c);
+ bool kingSide = kfrom < rfrom;
+ int cr = (kingSide ? WHITE_OO : WHITE_OOO) << c;
- st->castleRights |= f;
- castleRightsMask[king_square(c)] |= f;
- castleRightsMask[rsq] |= f;
- castleRookSquare[f] = rsq;
+ st->castleRights |= cr;
+ castleRightsMask[kfrom] |= cr;
+ castleRightsMask[rfrom] |= cr;
+ castleRookSquare[cr] = rfrom;
+
+ Square kto = relative_square(c, kingSide ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(c, kingSide ? SQ_F1 : SQ_D1);
+
+ for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[cr] |= s;
+
+ for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[cr] |= s;
}
// Castling rights
bool can_castle(CastleRight f) const;
bool can_castle(Color c) const;
+ bool castle_impeded(CastleRight f) const;
Square castle_rook_square(CastleRight f) const;
// Bitboards for pinned pieces and discovered check candidates
// Initialization helper functions (used while setting up a position)
void clear();
void put_piece(Piece p, Square s);
- void set_castle_right(Color c, Square rsq);
+ void set_castle_right(Color c, Square rfrom);
bool move_is_legal(const Move m) const;
// Helper template functions
// Other info
int castleRightsMask[64]; // [square]
Square castleRookSquare[16]; // [castleRight]
+ Bitboard castlePath[16]; // [castleRight]
StateInfo startState;
int64_t nodes;
int startPosPly;
return st->castleRights & ((WHITE_OO | WHITE_OOO) << c);
}
+inline bool Position::castle_impeded(CastleRight f) const {
+ return occupied & castlePath[f];
+}
+
inline Square Position::castle_rook_square(CastleRight f) const {
return castleRookSquare[f];
}