Variable (valid_ptr1 valid_ptr2 : block -> Z -> bool).
Let weak_valid_ptr1 b ofs := valid_ptr1 b ofs || valid_ptr1 b (ofs - 1).
Let weak_valid_ptr2 b ofs := valid_ptr2 b ofs || valid_ptr2 b (ofs - 1).
Hypothesis valid_ptr_inj:
forall b1 ofs b2 delta,
f b1 = Some(b2, delta) ->
valid_ptr1 b1 (Ptrofs.unsigned ofs) = true ->
valid_ptr2 b2 (Ptrofs.unsigned (Ptrofs.add ofs (Ptrofs.repr delta))) = true.
Hypothesis weak_valid_ptr_inj:
forall b1 ofs b2 delta,
f b1 = Some(b2, delta) ->
weak_valid_ptr1 b1 (Ptrofs.unsigned ofs) = true ->
weak_valid_ptr2 b2 (Ptrofs.unsigned (Ptrofs.add ofs (Ptrofs.repr delta))) = true.
Hypothesis weak_valid_ptr_no_overflow:
forall b1 ofs b2 delta,
f b1 = Some(b2, delta) ->
weak_valid_ptr1 b1 (Ptrofs.unsigned ofs) = true ->
0 <= Ptrofs.unsigned ofs + Ptrofs.unsigned (Ptrofs.repr delta) <= Ptrofs.max_unsigned.
Hypothesis valid_different_ptrs_inj:
forall b1 ofs1 b2 ofs2 b1' delta1 b2' delta2,
b1 <> b2 ->
valid_ptr1 b1 (Ptrofs.unsigned ofs1) = true ->
valid_ptr1 b2 (Ptrofs.unsigned ofs2) = true ->
f b1 = Some (b1', delta1) ->
f b2 = Some (b2', delta2) ->
b1' <> b2' \/
Ptrofs.unsigned (Ptrofs.add ofs1 (Ptrofs.repr delta1)) <> Ptrofs.unsigned (Ptrofs.add ofs2 (Ptrofs.repr delta2)).

Lemma hiword_inject:
forall v v', inject f v v' -> inject f (Val.hiword v) (Val.hiword v').