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https://opencores.org/ocsvn/eco32/eco32/trunk
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[/] [eco32/] [trunk/] [sim/] [mmu.c] - Rev 93
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/* * mmu.c -- MMU simulation */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <setjmp.h> #include "common.h" #include "console.h" #include "error.h" #include "except.h" #include "cpu.h" #include "mmu.h" #include "memory.h" static Bool debugUse = false; static Bool debugWrite = false; static TLB_Entry tlb[TLB_SIZE]; static Word tlbIndex; static Word tlbEntryHi; static Word tlbEntryLo; static Word mmuBadAddr; static int assoc(Word page) { int n, i; n = -1; for (i = 0; i < TLB_SIZE; i++) { if (tlb[i].page == page) { n = i; } } return n; } static void assocDelay(void) { int n, i; /* simulate delay introduced by assoc when using mapped addresses but not experienced with unmapped addresses */ n = -1; for (i = 0; i < TLB_SIZE; i++) { if (tlb[i].page == 0) { n = i; } } } static Word v2p(Word vAddr, Bool userMode, Bool writing) { Word pAddr; Word page, offset; int index; if (debugUse) { cPrintf("**** vAddr = 0x%08X", vAddr); } if ((vAddr & 0x80000000) != 0 && userMode) { /* trying to access a privileged address from user mode */ mmuBadAddr = vAddr; throwException(EXC_PRV_ADDRESS); } if ((vAddr & 0xC0000000) == 0xC0000000) { /* unmapped address space */ assocDelay(); pAddr = vAddr & ~0xC0000000; } else { /* mapped address space */ page = vAddr & PAGE_MASK; offset = vAddr & OFFSET_MASK; index = assoc(page); if (index == -1) { /* TLB miss exception */ mmuBadAddr = vAddr; tlbEntryHi = page; throwException(EXC_TLB_MISS); } if (!tlb[index].valid) { /* TLB invalid exception */ mmuBadAddr = vAddr; tlbEntryHi = page; throwException(EXC_TLB_INVALID); } if (!tlb[index].write && writing) { /* TLB write exception */ mmuBadAddr = vAddr; tlbEntryHi = page; throwException(EXC_TLB_WRITE); } pAddr = tlb[index].frame | offset; } if (debugUse) { cPrintf(", pAddr = 0x%08X ****\n", pAddr); } return pAddr; } Word mmuReadWord(Word vAddr, Bool userMode) { if ((vAddr & 3) != 0) { /* throw illegal address exception */ mmuBadAddr = vAddr; throwException(EXC_ILL_ADDRESS); } return memoryReadWord(v2p(vAddr, userMode, false)); } Half mmuReadHalf(Word vAddr, Bool userMode) { if ((vAddr & 1) != 0) { /* throw illegal address exception */ mmuBadAddr = vAddr; throwException(EXC_ILL_ADDRESS); } return memoryReadHalf(v2p(vAddr, userMode, false)); } Byte mmuReadByte(Word vAddr, Bool userMode) { return memoryReadByte(v2p(vAddr, userMode, false)); } void mmuWriteWord(Word vAddr, Word data, Bool userMode) { if ((vAddr & 3) != 0) { /* throw illegal address exception */ mmuBadAddr = vAddr; throwException(EXC_ILL_ADDRESS); } memoryWriteWord(v2p(vAddr, userMode, true), data); } void mmuWriteHalf(Word vAddr, Half data, Bool userMode) { if ((vAddr & 1) != 0) { /* throw illegal address exception */ mmuBadAddr = vAddr; throwException(EXC_ILL_ADDRESS); } memoryWriteHalf(v2p(vAddr, userMode, true), data); } void mmuWriteByte(Word vAddr, Byte data, Bool userMode) { memoryWriteByte(v2p(vAddr, userMode, true), data); } Word mmuGetIndex(void) { return tlbIndex; } void mmuSetIndex(Word value) { tlbIndex = value & TLB_MASK; } Word mmuGetEntryHi(void) { return tlbEntryHi; } void mmuSetEntryHi(Word value) { tlbEntryHi = value & PAGE_MASK; } Word mmuGetEntryLo(void) { return tlbEntryLo; } void mmuSetEntryLo(Word value) { tlbEntryLo = value & (PAGE_MASK | TLB_WRITE | TLB_VALID); } Word mmuGetBadAddr(void) { return mmuBadAddr; } void mmuSetBadAddr(Word value) { mmuBadAddr = value; } void mmuTbs(void) { int index; index = assoc(tlbEntryHi & PAGE_MASK); if (index == -1) { tlbIndex = 0x80000000; } else { tlbIndex = index; } } void mmuTbwr(void) { int index; /* choose a random index, but don't touch fixed entries */ do { index = rand() & TLB_MASK; } while (index < TLB_FIXED); tlb[index].page = tlbEntryHi & PAGE_MASK; tlb[index].frame = tlbEntryLo & PAGE_MASK; tlb[index].write = tlbEntryLo & TLB_WRITE ? true : false; tlb[index].valid = tlbEntryLo & TLB_VALID ? true : false; if (debugWrite) { cPrintf("**** TLB[%02d] <- 0x%08X 0x%08X %c %c ****\n", index, tlb[index].page, tlb[index].frame, tlb[index].write ? 'w' : '-', tlb[index].valid ? 'v' : '-'); } } void mmuTbri(void) { int index; index = tlbIndex & TLB_MASK; tlbEntryHi = tlb[index].page; tlbEntryLo = tlb[index].frame; if (tlb[index].write) { tlbEntryLo |= TLB_WRITE; } if (tlb[index].valid) { tlbEntryLo |= TLB_VALID; } } void mmuTbwi(void) { int index; index = tlbIndex & TLB_MASK; tlb[index].page = tlbEntryHi & PAGE_MASK; tlb[index].frame = tlbEntryLo & PAGE_MASK; tlb[index].write = tlbEntryLo & TLB_WRITE ? true : false; tlb[index].valid = tlbEntryLo & TLB_VALID ? true : false; if (debugWrite) { cPrintf("**** TLB[%02d] <- 0x%08X 0x%08X %c %c ****\n", index, tlb[index].page, tlb[index].frame, tlb[index].write ? 'w' : '-', tlb[index].valid ? 'v' : '-'); } } TLB_Entry mmuGetTLB(int index) { return tlb[index & TLB_MASK]; } void mmuSetTLB(int index, TLB_Entry tlbEntry) { index &= TLB_MASK; tlb[index] = tlbEntry; if (debugWrite) { cPrintf("**** TLB[%02d] <- 0x%08X 0x%08X %c %c ****\n", index, tlb[index].page, tlb[index].frame, tlb[index].write ? 'w' : '-', tlb[index].valid ? 'v' : '-'); } } void mmuReset(void) { int i; cPrintf("Resetting MMU...\n"); for (i = 0; i < TLB_SIZE; i++) { tlb[i].page = rand() & PAGE_MASK; tlb[i].frame = rand() & PAGE_MASK; tlb[i].write = rand() & 0x1000 ? true : false; tlb[i].valid = rand() & 0x1000 ? true : false; if (debugWrite) { cPrintf("**** TLB[%02d] <- 0x%08X 0x%08X %c %c ****\n", i, tlb[i].page, tlb[i].frame, tlb[i].write ? 'w' : '-', tlb[i].valid ? 'v' : '-'); } } tlbIndex = rand() & TLB_MASK; tlbEntryHi = rand() & PAGE_MASK; tlbEntryLo = rand() & (PAGE_MASK | TLB_WRITE | TLB_VALID); mmuBadAddr = rand(); } void mmuInit(void) { mmuReset(); } void mmuExit(void) { }
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