AddrSpace class Reference

Constructor & Destructor Documentation

AddrSpace::AddrSpace

(

executable

)

Definition at line 64 of file addrspace.cc.

References ASSERT, bzero, noffHeader::code, DEBUG, TranslationEntry::dirty, divRoundUp, FALSE, segment::inFileAddr, noffHeader::initData, NOFFMAGIC, noffHeader::noffMagic, numPages, NumPhysPages, PageSize, pageTable, TranslationEntry::physicalPage, OpenFile::ReadAt, TranslationEntry::readOnly, segment::size, SwapHeader, TRUE, noffHeader::uninitData, TranslationEntry::use, UserStackSize, TranslationEntry::valid, segment::virtualAddr, TranslationEntry::virtualPage, and WordToHost.

00065 {
00066     NoffHeader noffH;
00067     unsigned int i, size;
00068 
00069     executable->ReadAt((char *)&noffH, sizeof(noffH), 0);
00070     if ((noffH.noffMagic != NOFFMAGIC) && 
00071                 (WordToHost(noffH.noffMagic) == NOFFMAGIC))
00072         SwapHeader(&noffH);
00073     ASSERT(noffH.noffMagic == NOFFMAGIC);
00074 
00075 // how big is address space?
00076     size = noffH.code.size + noffH.initData.size + noffH.uninitData.size 
00077                         + UserStackSize;        // we need to increase the size
00078                                                 // to leave room for the stack
00079     numPages = divRoundUp(size, PageSize);
00080     size = numPages * PageSize;
00081 
00082     ASSERT(numPages <= NumPhysPages);           // check we're not trying
00083                                                 // to run anything too big --
00084                                                 // at least until we have
00085                                                 // virtual memory
00086 
00087     DEBUG('a', "Initializing address space, num pages %d, size %d\n", 
00088                                         numPages, size);
00089 // first, set up the translation 
00090     pageTable = new TranslationEntry[numPages];
00091     for (i = 0; i < numPages; i++) {
00092         pageTable[i].virtualPage = i;   // for now, virtual page # = phys page #
00093         pageTable[i].physicalPage = i;
00094         pageTable[i].valid = TRUE;
00095         pageTable[i].use = FALSE;
00096         pageTable[i].dirty = FALSE;
00097         pageTable[i].readOnly = FALSE;  // if the code segment was entirely on 
00098                                         // a separate page, we could set its 
00099                                         // pages to be read-only
00100     }
00101     
00102 // zero out the entire address space, to zero the unitialized data segment 
00103 // and the stack segment
00104     bzero(machine->mainMemory, size);
00105 
00106 // then, copy in the code and data segments into memory
00107     if (noffH.code.size > 0) {
00108         DEBUG('a', "Initializing code segment, at 0x%x, size %d\n", 
00109                         noffH.code.virtualAddr, noffH.code.size);
00110         executable->ReadAt(&(machine->mainMemory[noffH.code.virtualAddr]),
00111                         noffH.code.size, noffH.code.inFileAddr);
00112     }
00113     if (noffH.initData.size > 0) {
00114         DEBUG('a', "Initializing data segment, at 0x%x, size %d\n", 
00115                         noffH.initData.virtualAddr, noffH.initData.size);
00116         executable->ReadAt(&(machine->mainMemory[noffH.initData.virtualAddr]),
00117                         noffH.initData.size, noffH.initData.inFileAddr);
00118     }
00119 
00120 }

AddrSpace::~AddrSpace

(

)

Definition at line 127 of file addrspace.cc.

References pageTable.

00128 {
00129    delete pageTable;
00130 }

Member Function Documentation

void AddrSpace::InitRegisters

(

)

Definition at line 143 of file addrspace.cc.

References DEBUG, NextPCReg, numPages, NumTotalRegs, PageSize, PCReg, and StackReg.

Referenced by StartProcess.

00144 {
00145     int i;
00146 
00147     for (i = 0; i < NumTotalRegs; i++)
00148         machine->WriteRegister(i, 0);
00149 
00150     // Initial program counter -- must be location of "Start"
00151     machine->WriteRegister(PCReg, 0);   
00152 
00153     // Need to also tell MIPS where next instruction is, because
00154     // of branch delay possibility
00155     machine->WriteRegister(NextPCReg, 4);
00156 
00157    // Set the stack register to the end of the address space, where we
00158    // allocated the stack; but subtract off a bit, to make sure we don't
00159    // accidentally reference off the end!
00160     machine->WriteRegister(StackReg, numPages * PageSize - 16);
00161     DEBUG('a', "Initializing stack register to %d\n", numPages * PageSize - 16);
00162 }

void AddrSpace::RestoreState

(

)

Definition at line 183 of file addrspace.cc.

References numPages, and pageTable.

Referenced by StartProcess.

00184 {
00185     machine->pageTable = pageTable;
00186     machine->pageTableSize = numPages;
00187 }

void AddrSpace::SaveState

(

)

Definition at line 172 of file addrspace.cc.

00173 {}

Member Data Documentation

unsigned int AddrSpace::numPages [private]

Definition at line 37 of file addrspace.h.

Referenced by AddrSpace, InitRegisters, and RestoreState.

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Public Methods
	AddrSpace (OpenFile *executable)
	~AddrSpace ()
void	InitRegisters ()
void	SaveState ()
void	RestoreState ()
Private Attributes
TranslationEntry *	pageTable
unsigned int	numPages

AddrSpace Class Reference

Public Methods

Private Attributes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation