/*
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/*
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* mmu.h -- memory and TLB access
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* mmu.h -- memory and TLB access
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*/
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*/
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#ifndef _MMU_H_
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#ifndef _MMU_H_
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#define _MMU_H_
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#define _MMU_H_
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#define TLB_SHFT 5 /* log2 of number of TLB entries */
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#define TLB_SHFT 5 /* log2 of number of TLB entries */
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#define TLB_SIZE (1 << TLB_SHFT) /* total number of TLB entries */
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#define TLB_SIZE (1 << TLB_SHFT) /* total number of TLB entries */
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#define TLB_MASK (TLB_SIZE - 1) /* mask for number of TLB entries */
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#define TLB_MASK (TLB_SIZE - 1) /* mask for number of TLB entries */
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#define TLB_FIXED 4 /* number of fixed TLB entries */
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#define TLB_FIXED 4 /* number of fixed TLB entries */
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#define TLB_WRITE (1 << 1) /* write bit in EntryLo */
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#define TLB_WRITE (1 << 1) /* write bit in EntryLo */
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#define TLB_VALID (1 << 0) /* valid bit in EntryLo */
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#define TLB_VALID (1 << 0) /* valid bit in EntryLo */
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typedef struct {
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typedef struct {
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Word page; /* 20 high-order bits of virtual address */
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Word page; /* 20 high-order bits of virtual address */
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Word frame; /* 20 high-order bits of physical address */
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Word frame; /* 20 high-order bits of physical address */
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Bool write; /* must be true to allow writing to the page */
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Bool write; /* must be true to allow writing to the page */
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Bool valid; /* must be true for the entry to be valid */
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Bool valid; /* must be true for the entry to be valid */
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} TLB_Entry;
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} TLB_Entry;
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Word mmuReadWord(Word vAddr);
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Word mmuReadWord(Word vAddr);
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Half mmuReadHalf(Word vAddr);
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Half mmuReadHalf(Word vAddr);
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Byte mmuReadByte(Word vAddr);
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Byte mmuReadByte(Word vAddr);
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void mmuWriteWord(Word vAddr, Word data);
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void mmuWriteWord(Word vAddr, Word data);
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void mmuWriteHalf(Word vAddr, Half data);
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void mmuWriteHalf(Word vAddr, Half data);
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void mmuWriteByte(Word vAddr, Byte data);
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void mmuWriteByte(Word vAddr, Byte data);
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Word mmuGetIndex(void);
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Word mmuGetIndex(void);
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void mmuSetIndex(Word value);
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void mmuSetIndex(Word value);
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Word mmuGetEntryHi(void);
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Word mmuGetEntryHi(void);
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void mmuSetEntryHi(Word value);
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void mmuSetEntryHi(Word value);
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Word mmuGetEntryLo(void);
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Word mmuGetEntryLo(void);
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void mmuSetEntryLo(Word Value);
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void mmuSetEntryLo(Word value);
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Word mmuGetBadAddr(void);
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void mmuSetBadAddr(Word value);
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TLB_Entry mmuGetTLB(int index);
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TLB_Entry mmuGetTLB(int index);
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void mmuSetTLB(int index, TLB_Entry tlbEntry);
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void mmuSetTLB(int index, TLB_Entry tlbEntry);
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#endif /* _MMU_H_ */
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#endif /* _MMU_H_ */
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