(** Volatile memory accesses. *)
Definition do_volatile_load (w: world) (chunk: memory_chunk) (m: mem) (b: block) (ofs: ptrofs)
: option (world * trace * val) :=
if Genv.block_is_volatile ge b then
do id <- Genv.invert_symbol ge b;
match nextworld_vload w chunk id ofs with
| None => None
| Some(res, w') =>
do vres <- val_of_eventval res (type_of_chunk chunk);
Some(w', Event_vload chunk id ofs res :: nil, Val.load_result chunk vres)
end
else
do v <- Mem.load chunk m b (Ptrofs.unsigned ofs);
Some(w, E0, v).
Definition do_volatile_store (w: world) (chunk: memory_chunk) (m: mem) (b: block) (ofs: ptrofs) (v: val)
: option (world * trace * mem) :=
if Genv.block_is_volatile ge b then
do id <- Genv.invert_symbol ge b;
do ev <- eventval_of_val (Val.load_result chunk v) (type_of_chunk chunk);
do w' <- nextworld_vstore w chunk id ofs ev;
Some(w', Event_vstore chunk id ofs ev :: nil, m)
else
do m' <- Mem.store chunk m b (Ptrofs.unsigned ofs) v;
Some(w, E0, m').

Lemma do_volatile_load_sound:
forall w chunk m b ofs w' t v,
do_volatile_load w chunk m b ofs = Some(w', t, v) ->
volatile_load ge chunk m b ofs t v /\ possible_trace w t w'.