(** Preservation of loads. *)

Lemma loadbytes_inj:
forall f m1 m2 len b1 ofs b2 delta bytes1,
mem_inj f m1 m2 ->
loadbytes m1 b1 ofs len = Some bytes1 ->
f b1 = Some (b2, delta) ->
exists bytes2, loadbytes m2 b2 (ofs + delta) len = Some bytes2
/\ list_forall2 (memval_inject f) bytes1 bytes2.