(** [zero_ext n x] is the unique integer congruent to [x] modulo [2^n] in the range [0...2^n-1]. *)

(* Specifications: *)
Lemma zero_ext_range:
forall n x, 0 <= n < zwordsize -> 0 <= unsigned (zero_ext n x) < two_p n.
Lemma eqmod_zero_ext:
forall n x, 0 <= n < zwordsize -> eqmod (two_p n) (unsigned (zero_ext n x)) (unsigned x).
Lemma zero_ext_range:
forall n x, 0 <= n < zwordsize -> 0 <= unsigned (zero_ext n x) < two_p n.
Lemma eqmod_zero_ext:
forall n x, 0 <= n < zwordsize -> eqmod (two_p n) (unsigned (zero_ext n x)) (unsigned x).