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页面置换算法
提交 e1123eb8 创建 作者: 王晓庆's avatar 王晓庆
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页面置换算法

上级 c6519189
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.vscode/launch.json 0 → 100644
浏览文件 @ e1123eb8
{
"version": "0.2.0",
"configurations": [
{
"name": "(gdb) Launch",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceFolder}/pagereplacealgorithm.exe",
"targetArchitecture": "x86",
"args": [],
"stopAtEntry": false,
"cwd": "${workspaceFolder}",
"environment": [],
"externalConsole": false,
"preLaunchTask": "生成项目(make)",
"MIMode": "gdb",
"miDebuggerPath": "${execPath}.toolchain\\bin\\gdb.exe",
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
}
]
}
]
}
.vscode/settings.json 0 → 100644
浏览文件 @ e1123eb8
{
"files.exclude": {
}
}
.vscode/tasks.json 0 → 100644
浏览文件 @ e1123eb8
{
"version": "2.0.0",
"tasks": [
{
"label": "生成项目(make)",
"type": "shell",
"windows": {
"command": "cmd.exe /c echo VSCode安装路径-${execPath} ; echo ''; echo 正在使用makefile文件生成项目 ; echo ''; make",
"options": {
"env": {
"PATH": "${execPath}.toolchain\\bin;${execPath}.mingw64\\bin;${env:PATH}"
}
}
},
"args": [],
"group": "build",
"presentation": {
"reveal": "always",
"group": "make"
},
"problemMatcher": "$gcc"
},
{
"label": "清理项目(make clean)",
"type": "shell",
"windows": {
"command": "cmd.exe /c echo VSCode安装路径-${execPath} ; echo ''; echo 正在使用makefile文件清理项目 ; echo ''; make clean",
"options": {
"env": {
"PATH": "${execPath}.toolchain\\bin;${execPath}.mingw64\\bin;${env:PATH}"
}
}
},
"args": [],
"group": "build",
"presentation": {
"reveal": "always",
"group": "clean"
},
"problemMatcher": "$gcc"
}
]
}
main.c 0 → 100644
浏览文件 @ e1123eb8
#include <stdio.h>
#include <stdlib.h>
int main()
{
int *BlockofMemory; //内存物理块
const int BlockCount = 5;
int PageNumofRef[] = {7,0,1,2,0,3,0,4,2,3,0,1,1,7,0,1,0,3}; //页面号引用串
int PageNumRefCount = sizeof(PageNumofRef) / sizeof(PageNumofRef[0]);
BlockofMemory = (int*)malloc(BlockCount * sizeof(int));
if(BlockofMemory == (int*)NULL)
{
printf("内存分配出错\n");
exit(1);
}
ResetBlockofMemory(BlockofMemory, BlockCount);
Opt(BlockofMemory, PageNumofRef, BlockCount, PageNumRefCount);
ResetBlockofMemory(BlockofMemory,BlockCount);
Fifo(BlockofMemory, PageNumofRef, BlockCount, PageNumRefCount);
ResetBlockofMemory(BlockofMemory,BlockCount);
Lru(BlockofMemory, PageNumofRef, BlockCount, PageNumRefCount);
free(BlockofMemory);
return 0;
}
//输出内存块页面序号
int OutputBlockofMemory(int *BlockofMemory, int BlockCount, int ReplacePage, int PageNum)
{
int i;
printf("访问页面 %d 后，", PageNum);
printf("内存中的页面号为:\t");
for(i = 0; i < BlockCount; i++)
{
if(BlockofMemory[i] < 0)
printf("# ");
else
printf("%d ", BlockofMemory[i]);
}
if(ReplacePage != -1)
printf("\t淘汰页面号为:%d", ReplacePage);
printf("\n");
return -1;
}
//输出页面引用串号
void OutputPageNumofRef(int* PageNumofRef, int PageNumRefCount)
{
int i = 0;
printf("页面引用串为:\t");
for(i = 0; i < PageNumRefCount; i++)
printf("%d ", PageNumofRef[i]);
printf("\n");
}
//内存块页面号清零
void ResetBlockofMemory(int *BlockofMemory, int BlockCount)
{
int i;
for(i = 0; i < BlockCount; i++)
BlockofMemory[i] = -1;
}
//判断页是否在内存中，如果页在内存中，返回1，否则返回0；
int PageInBlockofMemory(int PageNum, int *BlockofMemory, int BlockCount)
{
int i;
for(i = 0; i < BlockCount; i++)
if(PageNum == BlockofMemory[i])
return 1;
return 0;
}
//下次访问次序
//参数j: 页面在内存块中的位置
//参数i： 页面号在页面号引用串中的位置
int DistanceOpt(int *BlockofMemory, int *PageNumofRef, int j, int i, int PageNumRefCount)
{
int k;
for(k = i + 1; k < PageNumRefCount; k++)
if(BlockofMemory[j] == PageNumofRef[k])
return k;
return PageNumRefCount;
}
//最佳页面置换算法
void Opt(int *BlockofMemory, int *PageNumofRef, int BlockCount, int PageNumRefCount)
{
int i, j, k;
int MaxIndex1, MaxIndex2;
int MissCount = 0;
int ReplacePage;
int EmptyBlockCount = BlockCount;
printf("**********最佳页面置换算法：**********\n");
//输出页面引用串号
OutputPageNumofRef(PageNumofRef, PageNumRefCount);
for(i = 0; i < PageNumRefCount; i++)
{
if(!PageInBlockofMemory(PageNumofRef[i], BlockofMemory, BlockCount)) //页不在内存中
{
MissCount++;
if(EmptyBlockCount > 0)
{
BlockofMemory[BlockCount - EmptyBlockCount] = PageNumofRef[i];
OutputBlockofMemory(BlockofMemory, BlockCount, -1, PageNumofRef[i]);
EmptyBlockCount--;
}
else
{
MaxIndex1 = MaxIndex2 = 0;
//求出未来最长时间不被访问的页
for(j = 0; j < BlockCount; j++)
{
MaxIndex2 = DistanceOpt(BlockofMemory, PageNumofRef, j, i, PageNumRefCount);
if(MaxIndex1 < MaxIndex2)
{
MaxIndex1 = MaxIndex2;
k = j;
}
}
ReplacePage = BlockofMemory[k];
BlockofMemory[k] = PageNumofRef[i];
OutputBlockofMemory(BlockofMemory, BlockCount, ReplacePage, PageNumofRef[i]);
}
}
else
{
OutputBlockofMemory(BlockofMemory,BlockCount, -1, PageNumofRef[i]);
}
}
printf("缺页次数为: %d\n", MissCount);
printf("OPT缺页率为: %.3f\n", (float)MissCount / PageNumRefCount);
}
//先进先出页面置换算法
void Fifo(int *BlockofMemory,int *PageNumofRef,int BlockCount,int PageNumRefCount)
{
int i;
int ReplacePage;
int ReplaceIndex = 0;
int MissCount = 0;
int EmptyBlockCount = BlockCount;
printf("**********先进先出页面置换算法：**********\n");
//输出页面引用串号
OutputPageNumofRef(PageNumofRef,PageNumRefCount);
for(i = 0; i < PageNumRefCount; i++)
{
if(!PageInBlockofMemory(PageNumofRef[i], BlockofMemory, BlockCount)) //页不在内存中
{
MissCount++;
if(EmptyBlockCount > 0)
{
BlockofMemory[BlockCount - EmptyBlockCount] = PageNumofRef[i];
OutputBlockofMemory(BlockofMemory, BlockCount, -1, PageNumofRef[i]);
EmptyBlockCount--;
}
else
{
ReplacePage = BlockofMemory[ReplaceIndex];
BlockofMemory[ReplaceIndex] = PageNumofRef[i];
ReplaceIndex = (ReplaceIndex + 1) % BlockCount;
OutputBlockofMemory(BlockofMemory, BlockCount, ReplacePage, PageNumofRef[i]);
}
}
else
OutputBlockofMemory(BlockofMemory, BlockCount, -1, PageNumofRef[i]);
}
printf("缺页次数为：%d\n", MissCount);
printf("FIFO缺页率为：%.3f\n", (float)MissCount / PageNumRefCount);
}
//最近最久未使用页面置换算法
void Lru(int *BlockofMemory, int *PageNumofRef, int BlockCount, int PageNumRefCount)
{
int i;
int MissCount = 0;
printf("************最近最久未使用页面置换算法：************\n");
//输出页面引用串号
OutputPageNumofRef(PageNumofRef, PageNumRefCount);
for(i = 0; i < PageNumRefCount; i++)
{
if(!PageInBlockofMemory(PageNumofRef[i], BlockofMemory, BlockCount)) //页不在内存中
{
MissCount++;
//
// 在此添加代码，实现 LRU 页面置换算法
//
}
else
OutputBlockofMemory(BlockofMemory, BlockCount, -1, PageNumofRef[i]);
}
printf("缺页次数为：%d\n", MissCount);
printf("LRU缺页率为：%.3f\n", (float)MissCount / PageNumRefCount);
}
makefile 0 → 100644
浏览文件 @ e1123eb8
DIR_INC = .
DIR_SRC = .
DIR_OBJ = .
DIR_BIN = .
SRC = $(wildcard ${DIR_SRC}/*.c)
OBJ = $(patsubst %.c,${DIR_OBJ}/%.o,$(notdir ${SRC}))
TARGET = pagereplacealgorithm.exe
BIN_TARGET = ${DIR_BIN}/${TARGET}
CC = gcc
CFLAGS = -g -w -std=c99 -fsigned-char -I${DIR_INC}
${BIN_TARGET}:${OBJ}
@echo --- build executable file: $@
$(CC) $(OBJ) -o $@
${DIR_OBJ}/%.o:${DIR_SRC}/%.c
@echo --- build object file: $@
$(CC) $(CFLAGS) -c $< -o $@
clean:
del /Q *.exe *.o
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