(** Effect of [free] on access validity. *)

(* Specifications: *)
Axiom valid_access_free_1:
forall m1 bf lo hi m2, free m1 bf lo hi = Some m2 ->
forall chunk b ofs p,
valid_access m1 chunk b ofs p ->
b <> bf \/ lo >= hi \/ ofs + size_chunk chunk <= lo \/ hi <= ofs ->
valid_access m2 chunk b ofs p.
Axiom valid_access_free_2:
forall m1 bf lo hi m2, free m1 bf lo hi = Some m2 ->
forall chunk ofs p,
lo < hi -> ofs + size_chunk chunk > lo -> ofs < hi ->
~(valid_access m2 chunk bf ofs p).
Axiom valid_access_free_inv_1:
forall m1 bf lo hi m2, free m1 bf lo hi = Some m2 ->
forall chunk b ofs p,
valid_access m2 chunk b ofs p ->
valid_access m1 chunk b ofs p.
Axiom valid_access_free_inv_2:
forall m1 bf lo hi m2, free m1 bf lo hi = Some m2 ->
forall chunk ofs p,
valid_access m2 chunk bf ofs p ->
lo >= hi \/ ofs + size_chunk chunk <= lo \/ hi <= ofs.