main.cpp

一个模仿操作系统的页面调度算法

#include "stdio.h"
#define BLOCKLENGTH 128
#define CAPABILITY 4
struct PAGETABLEITEM
{
	int  pageID;
	bool loaded;
	int  blockID;
	int  location;
	bool modified;
	PAGETABLEITEM *next;
};
typedef PAGETABLEITEM *itemPtr;

struct INSTRUCTION
{
	char operation;
	int  pageID;
	int  unitID;
	INSTRUCTION *next;
};
typedef INSTRUCTION *instrPtr;

PAGETABLEITEM defaultItem[7] =
{
	0, true, 5, 011, false, &defaultItem[1],
	1, true, 8, 012, false, &defaultItem[2],
	2, true, 9, 013, false, &defaultItem[3],
	3, true, 1, 021, false, &defaultItem[4],
	4, false,-1,022, false, &defaultItem[5],
	5, false,-1,023, false, &defaultItem[6],
	6, false,-1,121, false, NULL
};

INSTRUCTION defaultInstr[12] =
{
	'+', 0, 70, &defaultInstr[1],
	'+', 1, 50, &defaultInstr[2],
	'*', 2, 15, &defaultInstr[3],
	'S', 3, 21, &defaultInstr[4],
	'L', 0, 56, &defaultInstr[5],
	'-', 6, 40, &defaultInstr[6],
	'M', 4, 53, &defaultInstr[7],
	'+', 5, 23, &defaultInstr[8],
	'S', 1, 37, &defaultInstr[9],
	'L', 2, 78, &defaultInstr[10],
	'+', 4,  1, &defaultInstr[11],
	'S', 6, 84, NULL
};

int Mm[CAPABILITY];
int MmPtr = 0;

void getInstr(instrPtr instr);
void getPageID(instrPtr instr);
bool chkPageTbl(int pageID, itemPtr item);
void formAbAddr(int blockID, int unitID);
void interrupt(int pageID, itemPtr item);

void main()
{
	int i;
	int m;
	itemPtr item;
	instrPtr instr;
	for(i=0; i<CAPABILITY; i++)
		Mm[i] = i;
	printf("Would You Like to Load Default Data ?\n-----0 to Load Default;  Others to Input Your Data\n");
	scanf("%d", &i);
	if(i == 0)
	{
		item = defaultItem;
		instr = defaultInstr;
	}
	else
	{
		PAGETABLEITEM newItem[10];
		INSTRUCTION newInstr[20];
		
		for(i=0; i<10;i++)
		{
			printf("PAGE ID::");
			scanf("%d",&newItem[i].pageID);
			printf("LOADED (1 for yes)::");
			scanf("%d",&newItem[i].loaded);
			printf("BLOCK ID(-1 if not loaded)::");
			scanf("%d",&newItem[i].blockID);
			printf("LOCATION ON DISK::");
			scanf("%d",&newItem[i].location);
			printf("Any MORE(1 for yes)::");
			scanf("%d",&m);
			if(m)
				newItem[i].next = &newItem[i+1];
			else
				newItem[i].next = NULL;
		}
		for(i=0; i<20; i++)
		{
			printf("OPERATION ::");
			scanf("%c",&newInstr[i].operation);
			printf("PAGE ID::");
			scanf("%d",&newInstr[i].pageID);
			printf("BLOCK ID::");
			scanf("%d",&newInstr[i].unitID);
			printf("Any MORE(1 for yes)::");
			scanf("%d",&m);
			if(m)
				newInstr[i].next = &newInstr[i+1];
			else
				newInstr[i].next = NULL;
		}
		item = newItem;
		instr = newInstr;
	}

	while(instr)
	{
		printf("\n----------------------------\n");
		getInstr(instr);
		getPageID(instr);
		if(chkPageTbl(instr->pageID, item))
		{
			formAbAddr(item[instr->pageID].blockID, instr->unitID);
			if(instr->operation == 'S')
			{
				item[instr->pageID].modified = true;
				printf("Page %d Modified\n", instr->pageID);
			}
		}
		else
		{
			interrupt(instr->pageID, item);
			formAbAddr(item[instr->pageID].blockID, instr->unitID);
		}
		instr = instr->next;
		printf("----------------------------\n");
	}
}

void getInstr(instrPtr instr)
{
	printf("Operation::%c\n",instr->operation);
}
void getPageID(instrPtr instr)
{
	printf("Page   ID::%d\n",instr->pageID);
	/*printf("Modified ::");
	if(item[instr->pageID].modified)
		printf("YES\n");
	else
		printf("NO\n");*/
}

bool chkPageTbl(int pageID, itemPtr item)
{
	return item[pageID].loaded;
}

void formAbAddr(int blockID, int unitID)
{
	int addr;
	addr = blockID*BLOCKLENGTH + unitID;
	printf("Abso Addr::%d\n", addr);
}

void interrupt(int pageID, itemPtr item)
{
	int temp;
	printf("Miss Page::* %d\n",pageID);
	item[Mm[MmPtr]].loaded = false;
	temp = item[Mm[MmPtr]].blockID;
	item[Mm[MmPtr]].blockID = -1;
	if(item[Mm[MmPtr]].modified)
		printf("Page %d Unloaded\n", Mm[MmPtr]);
	else
	{
		printf("Page %d Overlayed\n", Mm[MmPtr]);
		item[Mm[MmPtr]].modified = false;
	}
	Mm[MmPtr] = pageID;
	item[pageID].blockID = temp;
	item[pageID].loaded = true;
	printf("Page %d Now Loaded\n", pageID);
	MmPtr = (MmPtr+1)%CAPABILITY;
}