Definition byte3 (x : int) : Z :=
  (Z.land (Int.unsigned (Int.shru x (Int.repr 24))) (Int.unsigned (Int.repr 255))).

Lemma byte3_def: byte3 = fun (x : int) => (Z.land (Int.unsigned (Int.shru x (Int.repr 24))) (Int.unsigned (Int.repr 255))).