Definition shr mrs e n :=
  match n with
  | Zpos p => (iter_pos shr_1 p mrs, (e + n)%Z)
  | _ => (mrs, e)
  end.

Lemma inbetween_shr_1 : forall x mrs e, (0 <= shr_m mrs)%Z -> inbetween_float radix2 (shr_m mrs) e x (loc_of_shr_record mrs) -> inbetween_float radix2 (shr_m (shr_1 mrs)) (e + 1) x (loc_of_shr_record (shr_1 mrs)).