Definition load8 id ofs :=
 (Sset id
      (Ederef
        (Ebinop Oadd
          (Efield
            (Ederef (Etempvar _ctx (tptr t_struct_SHA256state_st))
              t_struct_SHA256state_st) _h (tarray tuint 8))
          (Econst_int (Int.repr ofs) tint) (tptr tuint)) tuint)).

Lemma Znth_is_int: forall i r, 0 <= i < Zlength r -> is_int I32 Unsigned (Znth i (map Vint r)).