Definition StoreEffect (tv:val)(vl : list memval) (b:Values.block) (z:Z):bool :=
match tv with Vptr bb ofs => eq_block bb b &&
zle (Ptrofs.unsigned ofs) z && zlt z (Ptrofs.unsigned ofs + Z.of_nat (length vl))
| _ => false
end.

Lemma StoreEffect_Storev: forall m chunk tv tv' m'
(STORE : Mem.storev chunk m tv tv' = Some m'),
Mem.unchanged_on
(fun b ofs => StoreEffect tv (encode_val chunk tv') b ofs = false)
m m'.