// all squares attacked by the given color.
Bitboard attackedBy[2][8];
Bitboard attacked_by(Color c) const { return attackedBy[c][0]; }
Bitboard attacked_by(Color c, PieceType pt) const { return attackedBy[c][pt]; }
// kingZone[color] is the zone around the enemy king which is considered
// all squares attacked by the given color.
Bitboard attackedBy[2][8];
Bitboard attacked_by(Color c) const { return attackedBy[c][0]; }
Bitboard attacked_by(Color c, PieceType pt) const { return attackedBy[c][pt]; }
// kingZone[color] is the zone around the enemy king which is considered