| 1 | (* Memory model used in the dynamic semantics of the back-end intermediate |
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| 2 | languages. Inspired by common/Mem.ma, adapted from Compcert *) |
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| 3 | |
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| 4 | (* * This file develops the memory model that is used in the dynamic |
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| 5 | semantics of all the languages used in the compiler. |
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| 6 | It defines a type [mem] of memory states, the following 4 basic |
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| 7 | operations over memory states, and their properties: |
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| 8 | - [load]: read a memory chunk at a given address; |
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| 9 | - [store]: store a memory chunk at a given address; |
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| 10 | - [alloc]: allocate a fresh memory block; |
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| 11 | - [free]: invalidate a memory block. |
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| 12 | *) |
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| 13 | |
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| 14 | include "joint/BEValues.ma". |
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| 15 | include "common/GenMem.ma". |
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| 16 | |
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| 17 | definition becontentT ≝ mk_contentT beval BVundef. |
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| 18 | definition bemem ≝ mem becontentT. |
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| 19 | |
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| 20 | (* This function should be moved to common/GenMem.ma and replaces in_bounds *) |
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| 21 | definition do_if_in_bounds: |
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| 22 | ∀A:Type[0]. bemem → pointer → (block → block_contents becontentT → Z → A) → option A ≝ |
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| 23 | λS,m,ptr,F. |
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| 24 | let b ≝ pblock ptr in |
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| 25 | if Zltb (block_id b) (nextblock … m) then |
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| 26 | let content ≝ blocks … m b in |
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| 27 | let off ≝ offv (poff ptr) in |
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| 28 | if andb (Zleb (low … content) off) (Zleb off (high … content)) then |
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| 29 | Some … (F b content off) |
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| 30 | else |
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| 31 | None ? |
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| 32 | else |
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| 33 | None ?. |
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| 34 | |
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| 35 | definition beloadv: ∀m:bemem. ∀ptr:pointer. option beval ≝ |
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| 36 | λm,ptr. do_if_in_bounds … m ptr (λb,content,off. contents … content off). |
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| 37 | |
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| 38 | definition bestorev: ∀m:bemem. ∀ptr:pointer. beval → option bemem ≝ |
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| 39 | λm,ptr,v. do_if_in_bounds … m ptr |
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| 40 | (λb,content,off. |
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| 41 | let contents ≝ update … off v (contents … content) in |
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| 42 | let content ≝ mk_block_contents (mk_contentT beval BVundef) (low … content) (high … content) contents in |
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| 43 | let blocks ≝ update_block … b content (blocks … m) in |
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| 44 | mk_mem … blocks (nextblock … m) (nextblock_pos … m)). |
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| 45 | |
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| 46 | (* CSC: only pointers to XRAM or code memory ATM *) |
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| 47 | definition address ≝ beval × beval. |
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| 48 | |
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| 49 | definition eq_address: address → address → bool ≝ |
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| 50 | λaddr1,addr2. |
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| 51 | eq_beval (\fst addr1) (\fst addr2) ∧ eq_beval (\snd addr1) (\snd addr2). |
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| 52 | |
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| 53 | definition pointer_of_address: address → res pointer ≝ |
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| 54 | λp. let 〈v1,v2〉 ≝ p in pointer_of_bevals [v1;v2]. |
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| 55 | definition address_of_pointer: pointer → res address ≝ beval_pair_of_pointer. |
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| 56 | |
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| 57 | definition code_pointer_of_address: address → res (Σp:pointer. ptype p = Code) ≝ code_pointer_of_beval_pair. |
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| 58 | definition address_of_code_pointer: (Σp:pointer. ptype p = Code) → address ≝ beval_pair_of_code_pointer. |
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| 59 | |
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| 60 | definition addr_add: address → nat → res address ≝ |
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| 61 | λaddr,n. |
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| 62 | do ptr ← code_pointer_of_address addr ; |
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| 63 | OK … (address_of_code_pointer (shift_pointer 16 ptr (bitvector_of_nat … n))). |
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| 64 | normalize cases ptr #p #E @E |
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| 65 | qed. |
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| 66 | |
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| 67 | definition addr_sub: address → nat → res address ≝ |
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| 68 | λaddr,n. |
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| 69 | do ptr ← code_pointer_of_address addr ; |
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| 70 | OK … (address_of_code_pointer (neg_shift_pointer 16 ptr (bitvector_of_nat … n))). |
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| 71 | normalize cases ptr #p #E @E |
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| 72 | qed. |
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