119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
//#include "stdafx.h"
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#include<stdio.h>
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#include<stdlib.h>
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#include<stdbool.h>
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#define VM_PAGE 7 /*Number of virtual pages*/
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#define PM_PAGE 4 /* Number of memory blocks allocated to the job */
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#define TOTAL_INSERT 18 /*Number of virtual page replacements*/
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typedef struct
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{
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int vmn;
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int pmn;
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int exist;
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int time;
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}vpage_item;
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vpage_item page_table[VM_PAGE];
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vpage_item* ppage_bitmap[PM_PAGE];
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int vpage_arr[TOTAL_INSERT] = { 1,2,3,4,2,6,2,1,2,3,7,6,3,2,1,2,3,6 }; // The access order virtual pages
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void init_data() //initialize data
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{
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for (int i = 0; i<VM_PAGE; i++)
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{
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page_table[i].vmn = i + 1;
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page_table[i].pmn = -1;
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page_table[i].exist = 0;
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page_table[i].time = -1;
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}
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for (int i = 0; i<PM_PAGE; i++) /*initialize the physical page map*/
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{
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ppage_bitmap[i] = NULL;
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}
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}
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void FIFO()/*FIFO page replacement algorithem*/
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{
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int k = 0;
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int i;
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int sum = 0;
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int missing_page_count = 0;
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int current_time = 0;
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bool isleft = true; /* Whether there are remaining physical blocks */
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while (sum < TOTAL_INSERT)
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{
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if (page_table[vpage_arr[sum] - 1].exist == 0)
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{
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missing_page_count++;
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if (k < 4)
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{
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if (ppage_bitmap[k] == NULL) /*find a free block*/
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{
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ppage_bitmap[k] = &page_table[vpage_arr[sum] - 1];
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ppage_bitmap[k]->exist = 1;
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ppage_bitmap[k]->pmn = k;
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ppage_bitmap[k]->time = current_time;
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k++;
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}
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}
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else
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{
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int temp = ppage_bitmap[0]->time;
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int j = 0;
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for (i = 0; i < PM_PAGE; i++)
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{
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if (ppage_bitmap[i]->time < temp)
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{
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temp = ppage_bitmap[i]->time;
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j = i;
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}
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}
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ppage_bitmap[j]->exist = 0;
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ppage_bitmap[j] = &page_table[vpage_arr[sum] - 1]; /*update page table */
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ppage_bitmap[j]->exist = 1;
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ppage_bitmap[j]->pmn = j;
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ppage_bitmap[j]->time = current_time;
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}
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}
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current_time++;
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sum++;
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}
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printf("The number of page faults of FIFO is:%d\t Page fault rate:%f\t The number of replacement:%d\tReplacement rate:%f\n", missing_page_count, missing_page_count / (float)TOTAL_INSERT, missing_page_count - 4, (missing_page_count - 4) / (float)TOTAL_INSERT);
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}
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void LRU()
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{
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}
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void OPT()
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{
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}
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int main()
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{
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int a;
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do
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{
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printf("Please choose page replacement algorithm：1.FIFO\t2.LRU\t3.OPT\t0. quit\n");
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scanf_s("%d", &a);
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switch (a)
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{
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case 1:
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init_data();
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FIFO();
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break;
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case 2:
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init_data();
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LRU();
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break;
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case 3:
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init_data();
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OPT();
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break;
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}
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} while (a != 0);
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return 0;
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}
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