OS::NachOS::HW1

AddrSpace::AddrSpace()
{
    pageTable = new TranslationEntry[NumPhysPages];
    for (unsigned int i = 0; i < NumPhysPages; i++) {
        pageTable[i].virtualPage = i;   // for now, virt page # = phys page #
        pageTable[i].physicalPage = i;
//      pageTable[i].physicalPage = 0;
        pageTable[i].valid = TRUE;
//      pageTable[i].valid = FALSE;
        pageTable[i].use = FALSE;
        pageTable[i].dirty = FALSE;
        pageTable[i].readOnly = FALSE;
    }
    // 清空記憶體，但是不知道為什麼被註解掉了。
//    bzero(kernel->machine->mainMemory, MemorySize);
}

ASSERT(numPages <= NumPhysPages);

// then, copy the code and data segments into memory
if (noffH.code.size > 0) {
    DEBUG('a', "Initializing code segment, at 0x%x, size %d\n",noffH.code.virtualAddr, noffH.code.size);
    executable->ReadAt(&(machine->mainMemory[noffH.code.virtualAddr]),noffH.code.size, noffH.code.inFileAddr);
}
if (noffH.initData.size > 0) {
    DEBUG('a', "Initializing data segment, at 0x%x, size %d\n",noffH.initData.virtualAddr, noffH.initData.size);
    executable->ReadAt(&(machine->mainMemory[noffH.initData.virtualAddr]),noffH.initData.size, noffH.initData.inFileAddr);
}

class AddrSpace {
    ...
    private:
        ...
        static bool PhyPageStatus[NumPhysPages];
        static int NumFreePages;

}

#define PAGE_OCCU true
#define PAGE_FREE false
bool AddrSpace::PhyPageStatus[NumPhysPages] = {PAGE_FREE};
int AddrSpace::NumFreePages = NumPhysPages;

AddrSpace::AddrSpace()
{
}

bool AddrSpace::Load(char *fileName)
{
    ...
    //檢查是否有足夠的空閒實體頁
    ASSERT(numPages <= NumFreePages);
    //進行分配
    pageTable = new TranslationEntry[numPages];
    for(unsigned int i = 0, idx = 0; i < numPages; i++) {
        pageTable[i].virtualPage = i;
        while(idx < NumPhysPages && AddrSpace::PhyPageStatus[idx] == PAGE_OCCU) idx++;
        AddrSpace::PhyPageStatus[idx] = PAGE_OCCU;
        AddrSpace::NumFreePages--;
        //清空即將分配的 page
        bzero(&kernel->machine->mainMemory[idx * PageSize], PageSize);
        pageTable[i].physicalPage = idx;
        pageTable[i].valid = true;
        pageTable[i].use = false;
        pageTable[i].dirty = false;
        pageTable[i].readOnly = false;
    }

    DEBUG(dbgAddr, "Initializing address space: " << numPages << ", " << size);
    ...
}

bool AddrSpace::Load(char *fileName)
{
    ...
    DEBUG(dbgAddr, "Initializing address space: " << numPages << ", " << size);

    if (noffH.code.size > 0) {
        DEBUG(dbgAddr, "Initializing code segment.");
    DEBUG(dbgAddr, noffH.code.virtualAddr << ", " << noffH.code.size);
                executable->ReadAt(
        &(kernel->machine->mainMemory[pageTable[noffH.code.virtualAddr/PageSize].physicalPage * PageSize + (noffH.code.virtualAddr%PageSize)]),
            noffH.code.size, noffH.code.inFileAddr);
    }
    if (noffH.initData.size > 0) {
        DEBUG(dbgAddr, "Initializing data segment.");
    DEBUG(dbgAddr, noffH.initData.virtualAddr << ", " << noffH.initData.size);
        executable->ReadAt(
        &(kernel->machine->mainMemory[pageTable[noffH.initData.virtualAddr/PageSize].physicalPage * PageSize + (noffH.initData.virtualAddr%PageSize)]),
            noffH.initData.size, noffH.initData.inFileAddr);
    }

    delete executable;                  // close file
    return TRUE;                        // success
}

AddrSpace::~AddrSpace()
{
    //釋放本程式佔用的實體頁
    for(int i = 0; i < numPages; i++){
        AddrSpace::PhyPageStatus[pageTable[i].physicalPage] = PAGE_FREE;
        AddrSpace::NumFreePages++;
    }
    delete pageTable;
}

#define SC_ThreadFork   9
#define SC_ThreadYield  10
#define SC_PrintInt     11
#define SC_Sleep        12
...
void PrintInt(int number);      //my System Call
void Sleep(int number);

void Alarm::CallBack() {
    Interrupt *interrupt = kernel->interrupt;
    MachineStatus status = interrupt->getStatus();
    bool woken = _sleepList.PutToReady();
    //如果沒有程式需要計數了，就把時脈中斷遮蔽掉
    if (status == IdleMode && !woken && _sleepList.IsEmpty()) {// is it time to quit?
        if (!interrupt->AnyFutureInterrupts()) {
            timer->Disable();   // turn off the timer
        }
    } else {                    // there's someone to preempt
        interrupt->YieldOnReturn();
    }
}

void Alarm::WaitUntil(int x) {
    //關中斷
    IntStatus oldLevel = kernel->interrupt->SetLevel(IntOff);
    Thread* t = kernel->currentThread;
    cout << "Alarm::WaitUntil go sleep" << endl;
    _sleepList.PutToSleep(t, x);
    //開中斷
    kernel->interrupt->SetLevel(oldLevel);
}

bool sleepList::IsEmpty() {
    return _threadlist.size() == 0;
}

void sleepList::PutToSleep(Thread*t, int x) {
    ASSERT(kernel->interrupt->getLevel() == IntOff);
    _threadlist.push_back(sleepThread(t, _current_interrupt + x));
    t->Sleep(false);
}

bool sleepList::PutToReady() {
    bool woken = false;
    _current_interrupt ++;
    for(std::list<sleepThread>::iterator it = _threadlist.begin();
        it != _threadlist.end(); ) {
        if(_current_interrupt >= it->when) {
            woken = true;
            cout << "sleepList::PutToReady Thread woken" << endl;
            kernel->scheduler->ReadyToRun(it->sleeper);
            it = _threadlist.erase(it);
        } else {
            it++;
        }
    }
    return woken;
}

#include "syscall.h"
main() {
    int i;
    for(i = 0; i < 5; i++) {
        Sleep(1000000);
        PrintInt(2222);
    }
    return 0;
}

#include "syscall.h"
main() {
    int i;
    for(i = 0; i < 20; i++) {
        Sleep(100000);
        PrintInt(10);
    }
    return 0;
}

all: halt shell matmult sort test1 test2 sleep sleep2
...
sleep: sleep.o start.o
        $(LD) $(LDFLAGS) start.o sleep.o -o sleep.coff
        ../bin/coff2noff sleep.coff sleep

sleep2: sleep2.o start.o
        $(LD) $(LDFLAGS) start.o sleep2.o -o sleep2.coff
        ../bin/coff2noff sleep2.coff sleep2