Definition double d := rev (Little.double (rev d)).

(* Specifications: *)
Lemma double_unorm d : double (unorm d) = unorm (double d).
Lemma double_nzhead d : double (nzhead d) = nzhead (double d).
Lemma of_hex_uint_double d :
Pos.of_hex_uint (double d) = N.double (Pos.of_hex_uint d).