proposition: Theorem Z_frexp_spec : forall f, let (m,e) := Z.frexp f in (Prim2SF m, e) = SFfrexp prec emax (Prim2SF f).
proof: Proof. intro. unfold Z.frexp. case_eq (frshiftexp f). intros. assert (H' := frshiftexp_spec f). now rewrite H in H'. Qed.
imports: ZArith Uint63 SpecFloat PrimFloat FloatOps FloatAxioms Psatz