apply Rnd_UP_pt_unicity with (generic_format beta fexp) x...
apply round_UP_pt...
Qed.

(* Specifications: *)
Lemma d_ge_0: (0 <= F2R d)%R.
Proof with auto with typeclass_instances.
Lemma d_ge_0: (0 <= F2R d)%R.
Proof with auto with typeclass_instances.