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 StoreEffectD: forall vaddr v b ofs
(STE: StoreEffect vaddr v b ofs = true),
exists i, vaddr = Vptr b i /\
(Ptrofs.unsigned i) <= ofs < (Ptrofs.unsigned i + Z.of_nat (length v)).