计算机操作系统页面置换源码.docx

#include #include#includeusing namespace std;#define MEM_SIZE 32#define RAM_SIZE 16#define SWAP_SIZE 32static char ramRAM_SIZE;static char SwapSWAP_SIZE;map M;struct page_item / 页表项int ram_addr;int swap_addr;unsigned access;bool present;bool modified;static struct page_item page_tableMEM_SIZE;struct test_itemstruct test_item * next = NULL;int data;static struct test_item * first_list = NULL;static struct test_item * end_list = NULL;test_item head_item;test_item itemRAM_SIZE;/创建链表，保存地址的访问记录void init_test_list()first_list = &head_item;end_list = &head_item;for (int i = 0; i next = &itemi;itemi.data = i;end_list = &itemi;/ 换页算法static int algo_swap(void)return first_list-next-data;/ 逻辑地址laddr转换为物理地址paddrstatic int mem_access(int laddr)if (page_tableladdr.present) struct test_item * prev = first_list;struct test_item * cur = first_list-next;while (cur != NULL)if (cur-data = laddr)prev-next = cur-next;cur-next = NULL;end_list-next = cur;end_list = cur;break;prev = cur;cur = cur-next;return page_tableladdr.ram_addr;/ 缺页处理/ 根据特定算法选择被换出的页int page = algo_swap();struct test_item * prev = first_list;struct test_item * cur = first_list-next;while (cur != NULL)if (cur-data = page)prev-next = cur-next;cur-data = laddr;cur-next = NULL;end_list-next = cur;end_list = cur;break;prev = cur;cur = cur-next;/ 换出if (page_tablepage.modified) / 写回int data = rampage_tablepage.ram_addr;Swappage_tablepage.swap_addr = data;page_tablepage.present = false;/ 替换int paddr = page_tablepage.ram_addr;page_tableladdr.ram_addr = paddr;rampaddr = Swappage_tableladdr.swap_addr;page_tableladdr.modified = false;page_tableladdr.present = true;page_tableladdr.access = 1;return paddr;int mem_read(int addr, char *buf)if (addr MEM_SIZE)return -1;int paddr = mem_access(addr);*buf = rampaddr;/test_item item;return 0;int mem_write(int addr, char buf)if (addr MEM_SIZE)return -1;int paddr = mem_access(addr);rampaddr = buf;page_tableaddr.modified = true;return 0;void mem_init(void)/ 全部加载到交换空间for (int i = 0; i MEM_SIZE; i+) page_tablei.swap_addr = i;page_tablei.present = false;page_tablei.modified = false;/ 部分加载到内存for (int i = 0; i RAM_SIZE; i+) page_tablei.ram_addr = i;page_tablei.present = true;page_tablei.access = 0;void mem_state(void)printf(ram state:t);for (int i = 0; i RAM_SIZE; i+) printf(%d , rami);printf(nswap state:t);for (int i = 0; i next;printf(access record: n );while (cur != NULL)printf(%d , cur-data);prev = cur;cur = cur-next;void mem_test(void)printf(031为地址，在其中依次写入031，则前16个将会被置换n);int test10 = 1, 3, 5, 9, 6, 7, 19, 18, 31, 0 ;for (int i = 0; i 32; i+)mem_write(i, i);mem_state();history_show();printf(n访问22号单元，22链表末段 n );mem_write(22, 22);history_show();printf(n访问11单元， 11 链表末段，16re