| 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 bemem ≝ mem (mk_contentT beval BVundef). |
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| 18 | |
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| 19 | axiom beloadv: ∀m:bemem. ∀ptr:pointer. option beval. |
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| 20 | axiom bestorev: ∀m:bemem. ∀ptr:pointer. beval → option bemem. |
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| 21 | |
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| 22 | (* CSC: only pointers to XRAM or code memory ATM *) |
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| 23 | definition address ≝ beval × beval. |
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| 24 | |
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| 25 | definition eq_address: address → address → bool ≝ |
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| 26 | λaddr1,addr2. |
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| 27 | eq_beval (\fst addr1) (\fst addr2) ∧ eq_beval (\snd addr1) (\snd addr2). |
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| 28 | |
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| 29 | definition pointer_of_address: address → res pointer ≝ |
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| 30 | λp. let 〈v1,v2〉 ≝ p in pointer_of_bevals [v1;v2]. |
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| 31 | |
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| 32 | (*CSC: for pointers of type Code and XData, the next function type can be |
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| 33 | strengthtened to never fail *) |
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| 34 | definition address_of_pointer: pointer → res address ≝ beval_pair_of_pointer. |
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| 35 | |
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| 36 | definition addr_add: address → nat → res address ≝ |
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| 37 | λaddr,n. |
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| 38 | do ptr ← pointer_of_address addr ; |
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| 39 | address_of_pointer (shift_pointer 16 ptr (bitvector_of_nat … n)). |
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| 40 | |
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| 41 | definition addr_sub: address → nat → res address ≝ |
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| 42 | λaddr,n. |
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| 43 | do ptr ← pointer_of_address addr ; |
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| 44 | address_of_pointer (neg_shift_pointer 16 ptr (bitvector_of_nat … n)). |
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