source: src/RTL/semantics.ma @ 1415

Last change on this file since 1415 was 1415, checked in by sacerdot, 8 years ago
  1. hwreg_store/retrieve no longer returns a res (but it is still axiomatized)
  2. added initialization of local environment that sets the sp in the appropriate way
  3. ASM/I8051 splitted into ASM/I8051bis because of some bugs with disambiguation
File size: 7.2 KB
Line 
1include "joint/SemanticUtils.ma".
2include "RTL/RTL.ma". (* CSC: syntax.ma in RTLabs *)
3include alias "common/Identifiers.ma".
4include alias "ASM/Util.ma".
5
6record frame: Type[0] ≝
7 { fr_ret_regs: list register
8 ; fr_pc: address
9 ; fr_sp: pointer
10 ; fr_carry: beval
11 ; fr_regs: register_env beval
12 }.
13
14definition rtl_more_sem_params: more_sem_params rtl_params_ :=
15 mk_more_sem_params rtl_params_
16  (list frame) [] (register_env beval) (λ_.empty_map …) [] [](*dummy*) graph_succ_p
17   reg_store reg_retrieve reg_store reg_retrieve reg_store reg_retrieve
18    reg_store reg_retrieve reg_store reg_retrieve
19     (λlocals,dest_src.
20       do v ← reg_retrieve locals (\snd dest_src) ;
21       reg_store (\fst dest_src) v locals)
22     pointer_of_label.
23definition rtl_sem_params: sem_params ≝ mk_sem_params … rtl_more_sem_params.
24
25definition rtl_init_locals :
26 list register → register_env beval → register_env beval ≝
27 λlocals,env.
28  foldl ?? (λlenv,reg. add … lenv reg BVundef) env locals.
29
30(*CSC: could we use here a dependent type to avoid the Error case? *)
31axiom EmptyStack: String.
32axiom OutOfBounds: String.
33
34definition rtl_fetch_ra:
35 state … rtl_sem_params → res ((state … rtl_sem_params) × address) ≝
36 λst.
37  match st_frms ? st with
38  [ nil ⇒ Error ? [MSG EmptyStack]
39  | cons hd tl ⇒ OK … 〈st, fr_pc hd〉 ].
40
41definition rtl_result_regs:
42 ∀globals. genv … (rtl_params globals) → state rtl_sem_params → res (list register) ≝
43 λglobals,ge,st.
44  do fn ← graph_fetch_function … globals ge st ;
45  OK … (joint_if_result … fn).
46
47(*CSC: we could use a dependent type here: the list of return values should have
48  the same length of the list of return registers that store the values. This
49  saves the OutOfBounds exception *)
50definition rtl_pop_frame:
51 ∀globals. genv … (rtl_params globals) → state … rtl_sem_params → res (state … rtl_sem_params) ≝
52 λglobals,ge,st.
53  do ret_regs ← rtl_result_regs … ge st ;
54  do ret_vals ← mmap … (λreg.greg_retrieve rtl_sem_params st reg) ret_regs ;
55  match st_frms ? st with
56  [ nil ⇒ Error ? [MSG EmptyStack]
57  | cons hd tl ⇒
58     do st ←
59      mfold_left_i ??
60       (λi.λst.λreg.
61         do v ← opt_to_res ? [MSG OutOfBounds] (nth_opt … i ret_vals) ;
62         greg_store rtl_sem_params reg v st)
63       (OK … st) (fr_ret_regs hd) ;
64     OK …
65      (set_frms rtl_sem_params tl
66        (set_regs rtl_sem_params (fr_regs hd)
67         (set_sp … (fr_sp hd)
68          (set_carry … (fr_carry hd)
69           (set_m … (free … (m … st) (pblock (sp … st))) st)))))].
70
71definition rtl_call_function:
72 nat → list register → list register → state … rtl_sem_params → res (state … rtl_sem_params) ≝
73  λstacksize,formal_arg_regs,actual_arg_regs,st.
74  let 〈mem,b〉 ≝ alloc … (m … st) 0 stacksize XData in
75  do new_regs ←
76   mfold_left2 …
77    (λlenv,dest,src.
78      do v ← greg_retrieve … st src ;
79      OK … (add … lenv dest v))
80    (OK … (empty_map …)) formal_arg_regs actual_arg_regs ;
81  OK …
82   (set_regs rtl_sem_params new_regs
83    (set_m … mem
84     (set_sp … (mk_pointer XData b ? (mk_offset 0)) st))).
85cases b * #r #off #E >E %
86qed.
87
88definition rtl_save_frame:
89 address → nat → list register → list register → list register → state … rtl_sem_params → res (state … rtl_sem_params) ≝
90 λl,stacksize,formal_arg_regs,actual_arg_regs,retregs,st.
91  let frame ≝ mk_frame retregs l (sp … st) (carry … st) (regs … st) :: (st_frms … st) in
92  let st ≝ set_frms rtl_sem_params frame st in
93  rtl_call_function stacksize formal_arg_regs actual_arg_regs st.
94
95(*CSC: XXXX, for external functions only*)
96axiom rtl_fetch_external_args: external_function → state rtl_sem_params → res (list val).
97axiom rtl_set_result: list val → state rtl_sem_params → res (state rtl_sem_params).
98
99definition rtl_more_sem_params1: ∀globals. more_sem_params1 … (rtl_params globals) ≝
100 λglobals.
101  mk_more_sem_params1 … rtl_more_sem_params
102   (graph_fetch_statement …) rtl_fetch_ra (rtl_result_regs …)
103   rtl_init_locals rtl_save_frame (rtl_pop_frame …)
104   rtl_fetch_external_args rtl_set_result.
105
106definition block_of_register_pair: register → register → state rtl_sem_params → res block ≝
107 λr1,r2,st.
108 do v1 ← greg_retrieve rtl_sem_params st r1 ;
109 do v2 ← greg_retrieve rtl_sem_params st r2 ;
110 do ptr ← pointer_of_address 〈v1,v2〉 ;
111 OK … (pblock ptr). 
112
113(* This code is quite similar to eval_call_block: can we factorize it out? *)
114definition eval_tail_call_block:
115 ∀globals.genv … (rtl_params globals) → state rtl_sem_params →
116  block → call_args rtl_sem_params → IO io_out io_in (trace×(state rtl_sem_params)) ≝
117 λglobals,ge,st,b,args.
118  ! fd ← opt_to_res … [MSG BadPointer] (find_funct_ptr ?? ge b);
119    match fd with
120    [ Internal fn ⇒
121      let st ≝ set_m … (free … (m … st) (pblock (sp … st))) st in
122      ! st ← rtl_call_function (joint_if_stacksize … fn) (joint_if_params … fn) args st ;
123      let regs ≝ rtl_init_locals … (joint_if_locals … fn) (regs … st) in
124      let l' ≝ joint_if_entry … fn in
125       ret ? 〈 E0, goto … l' (set_regs rtl_sem_params regs st)〉
126    | External fn ⇒ ?(*
127      ! params ← fetch_external_args … fn st;
128      ! evargs ← check_eventval_list params (sig_args (ef_sig fn));
129      ! evres ← do_io (ef_id fn) evargs (proj_sig_res (ef_sig fn));
130      (* CSC: XXX bug here; I think I should split it into Byte-long
131         components; instead I am making a singleton out of it. To be
132         fixed once we fully implement external functions. *)
133        let vs ≝ [mk_val ? evres] in
134      ! st ← set_result … vs st;
135      let st ≝ set_pc … ra st in
136        ret ? 〈Eextcall (ef_id fn) evargs (mk_eventval ? evres), st〉 *)
137     ].
138cases daemon (*CSC: XXX tailcall to external function not implemented yet;
139                    it needs alls other functions on external calls *)
140qed.
141
142definition rtl_exec_extended:
143 ∀globals. genv globals (rtl_params globals) →
144  rtl_statement_extension → label → state rtl_sem_params →
145   IO io_out io_in (trace × (state rtl_sem_params)) ≝
146 λglobals,ge,stm,l,st.
147  match stm with
148   [ rtl_st_ext_stack_address dreg1 dreg2  ⇒
149      let sp ≝ sp ? st in
150      ! 〈dpl,dph〉 ← beval_pair_of_pointer sp ;
151      ! st ← greg_store rtl_sem_params dreg1 dpl st ;
152      ! st ← greg_store rtl_sem_params dreg2 dph st ;
153       ret ? 〈E0, goto … l st〉
154   | rtl_st_ext_call_ptr r1 r2 args dest ⇒
155      ! b ← block_of_register_pair r1 r2 st ;
156      ! ra ← succ_pc … (rtl_more_sem_params1 globals) l (pc … st) ;
157      eval_call_block … (mk_sem_params1 … (rtl_more_sem_params1 globals))
158       ge st b args dest ra
159   | rtl_st_ext_tailcall_id id args ⇒
160      ! b ← opt_to_res … [MSG MissingSymbol; CTX ? id] (find_symbol ?? ge id);
161      eval_tail_call_block … ge st b args
162   | rtl_st_ext_tailcall_ptr r1 r2 args ⇒
163      ! b ← block_of_register_pair r1 r2 st ;
164      eval_tail_call_block … ge st b args
165   ].
166
167definition rtl_more_sem_params2: ∀globals. more_sem_params2 … (rtl_params globals) ≝
168 λglobals. mk_more_sem_params2 … (rtl_more_sem_params1 globals) (rtl_exec_extended …).
169
170definition rtl_fullexec ≝
171 joint_fullexec … (λp. rtl_more_sem_params2 (prog_var_names … p)).
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