#include <stdio.h>
#define MEMERYSIZE 0xA000 //内存大小40k
#define PAGESIZE 0x1000 //每页 4KB
#define PAGETABLELENGTH (MEMERYSIZE / PAGESIZE) //页表长度10
typedef struct{ //定义寄存器结构体
int * startAddress; //页表始址
int pageTableSize; //页表长度
}reg;
typedef struct{
int pageNumber; //页号
int insideAddress; //页内地址
}logicAddress; // 逻辑地址
// 页表
int pageTable[PAGETABLELENGTH];
// 页表寄存器
static reg pageTableReg = {pageTable, PAGETABLELENGTH};
// 建立页表
void createPageTable(){
int i;
for(i = 0; i < PAGETABLELENGTH; i++){
pageTable[i] = i + 1;
}
}
// 地址变换
int varyAddress(logicAddress laddress){
int maddress = -1;//初始化物理地址
int blocknumber;//块号
if(laddress.pageNumber > pageTableReg.pageTableSize - 1 || laddress.pageNumber < 0){
return -1; // -1 表示越界
}
if(laddress.insideAddress > PAGESIZE - 1 ){
return -2; //页内地址超过最大页面地址
}else if(laddress.insideAddress < 0){
return -3; //页内地址不能为负数
}
blocknumber = *(pageTableReg.startAddress + laddress.pageNumber);//计算块号
return maddress = (blocknumber - 1) * PAGESIZE + laddress.insideAddress;//计算物理地址
}
void printPageTable(){
int i;
printf("\n页号\t块号\n");
for(i = 0; i < PAGETABLELENGTH; i++)
printf("%d\t%d\n", i, pageTable[i]);
}
// 显示
void print(){
logicAddress laddress;
int blocknumber;
int maddress = -1;
printf("输入页号：");
scanf("%d", &laddress.pageNumber);
printf("输入页内地址：");
scanf("%d", &laddress.insideAddress);
maddress = varyAddress(laddress);//地址变换
if(maddress == -1){
printf("页号越界！\n\n");
} else if(maddress == -2){
printf("页内地址超过最大页面地址！\n\n");
} else if(maddress == -3){
printf("页内地址不能为负数！\n\n");
} else{
printPageTable();
blocknumber = *(pageTableReg.startAddress + laddress.pageNumber);
printf("\n物理地址 = (块号 - 1) * 页面大小 + 页内地址 \n\t = (%d - 1) * %d + %d \n\t = %d\n\n",\
blocknumber, PAGESIZE, laddress.insideAddress, maddress);
}
}
int main(){
createPageTable();
while(1) //无限循环
print();
return 0;
}
