(** * Memory injections *)
(** A memory injection [f] is a function from addresses to either [None] or [Some] of an address and an offset.  It defines a correspondence between the blocks of two memory states [m1] and [m2]: - if [f b = None], the block [b] of [m1] has no equivalent in [m2]; - if [f b = Some(b', ofs)], the block [b] of [m2] corresponds to a sub-block at offset [ofs] of the block [b'] in [m2].  A memory injection [f] defines a relation [Val.inject] between values that is the identity for integer and float values, and relocates pointer values as prescribed by [f].  (See module [Values].)  Likewise, a memory injection [f] defines a relation between memory states that we now axiomatize. *)
Parameter inject: meminj -> mem -> mem -> Prop.

Axiom valid_pointer_inject_no_overflow:
forall f m1 m2 b ofs b' delta,
inject f m1 m2 ->
valid_pointer m1 b (Ptrofs.unsigned ofs) = true ->
f b = Some(b', delta) ->
0 <= Ptrofs.unsigned ofs + Ptrofs.unsigned (Ptrofs.repr delta) <= Ptrofs.max_unsigned.