(*Obtained from Cminor.state by deleting the memory components.*)
Inductive CMin_core: Type :=
| CMin_State:                      (**r Execution within a function *)
forall (f: function)              (**r currently executing function  *)
(s: stmt)                  (**r statement under consideration *)
(k: cont)                  (**r its continuation -- what to do next *)
(sp: val)                  (**r current stack pointer *)
(e: env),                   (**r current local environment *)
CMin_core
| CMin_Callstate:                  (**r Invocation of a function *)
forall (f: fundef)                (**r function to invoke *)
(args: list val)           (**r arguments provided by caller *)
(k: cont),                  (**r what to do next  *)
CMin_core
| CMin_Returnstate:                (**r Return from a function *)
forall (v: val)                   (**r Return value *)
(k: cont),                  (**r what to do next *)
CMin_core.
Definition ToState (q:CMin_core) (m:mem): Cminor.state :=
match q with
CMin_State f s k sp e => State f s k sp e m
| CMin_Callstate f args k => Callstate f args k m
| CMin_Returnstate v k => Returnstate v k m
end.
Definition FromState (c: Cminor.state) : CMin_core * mem :=
match c with
State f s k sp e m => (CMin_State f s k sp e, m)
| Callstate f args k m => (CMin_Callstate f args k, m)
| Returnstate v k m => (CMin_Returnstate v k, m)
end.
(* Definition CMin_init_mem (ge:genv)  (m:mem) d:  Prop:= Genv.alloc_variables ge Mem.empty d = Some m. (*Defined initial memory, by adapting the definition of Genv.init_mem*)
*)
(* initial_core : G -> val -> list val -> option C;*)
Definition CMin_initial_core (ge:Cminor.genv) (v: val) (args:list val): option CMin_core :=
match v with
Vptr b i =>
if Int.eq_dec i  Int.zero
then match Genv.find_funct_ptr ge b with
| None => None
| Some f => Some (CMin_Callstate f args Kstop)
end
else None
| _ => None
end.
(* Parameter CMin_MainIdent:ident.  Definition CMin_make_initial_core (ge:genv) (v: val) (args:list val): option CMin_core := match Genv.find_symbol ge CMin_MainIdent with None => None | Some b => match Genv.find_funct_ptr ge b with None => None | Some f => match funsig f with {| sig_args := sargs; sig_res := sres |} => match sargs, sres with nil, Some Tint => Some (CMin_Callstate f nil Kstop) (*args = nil???*)
| _ , _ => None
end
end
end
end.
*)
(*Original Cminor_semantics has this for initial states: Genv.find_symbol ge p.(prog_main) = Some b -> Genv.find_funct_ptr ge b = Some f -> funsig f = mksignature nil (Some Tint) -> initial_state p (Callstate f nil Kstop m0).*)
Definition CMin_at_external (c: CMin_core) : option (external_function * signature * list val) :=
match c with
| CMin_State f s k sp e => None
| CMin_Callstate fd args k => match fd with
Internal f => None
| External ef => Some (ef, ef_sig ef, args)
end
| CMin_Returnstate v k => None
end.
Definition CMin_after_external (vret: option val) (c: CMin_core) : option CMin_core :=
match c with
CMin_Callstate fd args k =>
match fd with
Internal f => None
| External ef => match vret with
None => Some (CMin_Returnstate Vundef k)
| Some v => Some (CMin_Returnstate v k)
end
end
| _ => None
end.
Inductive CMin_corestep (ge : genv) : CMin_core -> mem -> CMin_core -> mem -> Prop:=
| cmin_corestep_skip_seq: forall f s k sp e m,
CMin_corestep ge (CMin_State f Sskip (Kseq s k) sp e) m
(CMin_State f s k sp e) m
| cmin_corestep_skip_block: forall f k sp e m,
CMin_corestep ge (CMin_State f Sskip (Kblock k) sp e) m
(CMin_State f Sskip k sp e) m
| cmin_corestep_skip_call: forall f k sp e m m',
is_call_cont k ->
Mem.free m sp 0 f.(fn_stackspace) = Some m' ->
CMin_corestep ge (CMin_State f Sskip k (Vptr sp Int.zero) e) m
(CMin_Returnstate Vundef k) m'
| cmin_corestep_assign: forall f id a k sp e m v,
eval_expr ge sp e m a v ->
CMin_corestep ge (CMin_State f (Sassign id a) k sp e) m
(CMin_State f Sskip k sp (PTree.set id v e)) m
| cmin_corestep_store: forall f chunk addr a k sp e m vaddr v m',
eval_expr ge sp e m addr vaddr ->
eval_expr ge sp e m a v ->
Mem.storev chunk m vaddr v = Some m' ->
CMin_corestep ge (CMin_State f (Sstore chunk addr a) k sp e) m
(CMin_State f Sskip k sp e) m'
| cmin_corestep_call: forall f optid sig a bl k sp e m vf vargs fd,
eval_expr ge sp e m a vf ->
eval_exprlist ge sp e m bl vargs ->
Genv.find_funct ge vf = Some fd ->
funsig fd = sig ->
CMin_corestep ge (CMin_State f (Scall optid sig a bl) k sp e) m
(CMin_Callstate fd vargs (Kcall optid f sp e k)) m
| cmin_corestep_tailcall: forall f sig a bl k sp e m vf vargs fd m',
eval_expr ge (Vptr sp Int.zero) e m a vf ->
eval_exprlist ge (Vptr sp Int.zero) e m bl vargs ->
Genv.find_funct ge vf = Some fd ->
funsig fd = sig ->
Mem.free m sp 0 f.(fn_stackspace) = Some m' ->
CMin_corestep ge (CMin_State f (Stailcall sig a bl) k (Vptr sp Int.zero) e) m
(CMin_Callstate fd vargs (call_cont k)) m'
(* WE DO NOT TREAT BUILTINS *)
(*  | cmin_corestep_builtin: forall f optid ef bl k sp e m vargs t vres m', eval_exprlist ge sp e m bl vargs -> external_call ef ge vargs m t vres m' -> CMin_corestep ge (CMin_State f (Sbuiltin optid ef bl) k sp e) m (CMin_State f Sskip k sp (set_optvar optid vres e)) m'*)
| cmin_corestep_seq: forall f s1 s2 k sp e m,
CMin_corestep ge (CMin_State f (Sseq s1 s2) k sp e) m
(CMin_State f s1 (Kseq s2 k) sp e) m
| cmin_corestep_ifthenelse: forall f a s1 s2 k sp e m v b,
eval_expr ge sp e m a v ->
Val.bool_of_val v b ->
CMin_corestep ge (CMin_State f (Sifthenelse a s1 s2) k sp e) m
(CMin_State f (if b then s1 else s2) k sp e) m
| cmin_corestep_loop: forall f s k sp e m,
CMin_corestep ge (CMin_State f (Sloop s) k sp e) m
(CMin_State f s (Kseq (Sloop s) k) sp e) m
| cmin_corestep_block: forall f s k sp e m,
CMin_corestep ge (CMin_State f (Sblock s) k sp e) m
(CMin_State f s (Kblock k) sp e) m
| cmin_corestep_exit_seq: forall f n s k sp e m,
CMin_corestep ge (CMin_State f (Sexit n) (Kseq s k) sp e) m
(CMin_State f (Sexit n) k sp e) m
| cmin_corestep_exit_block_0: forall f k sp e m,
CMin_corestep ge (CMin_State f (Sexit O) (Kblock k) sp e) m
(CMin_State f Sskip k sp e) m
| cmin_corestep_exit_block_S: forall f n k sp e m,
CMin_corestep ge (CMin_State f (Sexit (S n)) (Kblock k) sp e) m
(CMin_State f (Sexit n) k sp e) m
| cmin_corestep_switch: forall f a cases default k sp e m n,
eval_expr ge sp e m a (Vint n) ->
CMin_corestep ge (CMin_State f (Sswitch a cases default) k sp e) m
(CMin_State f (Sexit (switch_target n default cases)) k sp e) m
| cmin_corestep_return_0: forall f k sp e m m',
Mem.free m sp 0 f.(fn_stackspace) = Some m' ->
CMin_corestep ge (CMin_State f (Sreturn None) k (Vptr sp Int.zero) e) m
(CMin_Returnstate Vundef (call_cont k)) m'
| cmin_corestep_return_1: forall f a k sp e m v m',
eval_expr ge (Vptr sp Int.zero) e m a v ->
Mem.free m sp 0 f.(fn_stackspace) = Some m' ->
CMin_corestep ge (CMin_State f (Sreturn (Some a)) k (Vptr sp Int.zero) e) m
(CMin_Returnstate v (call_cont k)) m'
| cmin_corestep_label: forall f lbl s k sp e m,
CMin_corestep ge (CMin_State f (Slabel lbl s) k sp e) m
(CMin_State f s k sp e) m
| cmin_corestep_goto: forall f lbl k sp e m s' k',
find_label lbl f.(fn_body) (call_cont k) = Some(s', k') ->
CMin_corestep ge (CMin_State f (Sgoto lbl) k sp e) m
(CMin_State f s' k' sp e) m
| cmin_corestep_internal_function: forall f vargs k m m' sp e,
Mem.alloc m 0 f.(fn_stackspace) = (m', sp) ->
set_locals f.(fn_vars) (set_params vargs f.(fn_params)) = e ->
CMin_corestep ge (CMin_Callstate (Internal f) vargs k) m
(CMin_State f f.(fn_body) k (Vptr sp Int.zero) e) m'
(*no external call | step_external_function: forall ef vargs k m t vres m', external_call ef ge vargs m t vres m' -> sCMin_coretep (CMin_Callstate (External ef) vargs k) m t (CMin_Returnstate vres k m') *)
| cmin_corestep_return: forall v optid f sp e k m,
CMin_corestep ge (CMin_Returnstate v (Kcall optid f sp e k)) m
(CMin_State f Sskip k sp (set_optvar optid v e)) m.

Lemma CMin_corestep_not_at_external:
forall ge m q m' q', CMin_corestep ge q m q' m' -> CMin_at_external q = None.