Definition Fnormalize (p : float) :=
  match Z_zerop (Fnum p) with
  | left _ => Float 0 (- dExp b)
  | right _ =>
      Fshift radix
        (min (precision - Fdigit radix p) (Zabs_nat (dExp b + Fexp p))) p
  end.

Theorem FcanonicNegFexpRlt : forall x y : float, (x <= 0)%R -> (y <= 0)%R -> Fcanonic x -> Fcanonic y -> (Fexp x < Fexp y)%Z -> (y < x)%R.