深入理解计算机系统Cache实验源代码

最新推荐文章于 2025-05-14 21:23:49 发布

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最新推荐文章于 2025-05-14 21:23:49 发布 · 2.2k 阅读

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这段代码展示了如何实现一个简单的Cache模拟器，包括初始化Cache、访问数据、回放跟踪文件等功能。通过命令行参数设置Cache的大小、块大小和关联度，并使用LRU替换策略。访问数据时，如果命中则增加命中计数，未命中则增加缺失计数，并可能触发驱逐操作。

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#include <getopt.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <assert.h>
#include <math.h>
#include <limits.h>
#include <string.h>
#include <errno.h>
#include "cachelab.h"

//#define DEBUG_ON
#define ADDRESS_LENGTH 64

/* Type: Memory address */
typedef unsigned long long int mem_addr_t;

/* Type: Cache line
LRU is a counter used to implement LRU replacement policy */
typedef struct cache_line
{
char valid;
mem_addr_t tag;
unsigned long long int lru;
} cache_line_t;

typedef cache_line_t* cache_set_t;
typedef cache_set_t* cache_t;

/* Globals set by command line args */
int verbosity = 0; /* print trace if set */
int s = 0; /* set index bits */
int b = 0; /* block offset bits */
int E = 0; /* associativity */
char* trace_file = NULL;

/* Derived from command line args */
int S; /* number of sets */
int B; /* block size (bytes) */

/* Counters used to record cache statistics */
int miss_count = 0;
int hit_count = 0;
int eviction_count = 0;
unsigned long long int lru_counter = 1;

/* The cache we are simulating */
cache_t cache;
mem_addr_t set_index_mask;

/*
* initCache - Allocate memory, write 0's for valid and tag and LRU
*
*/
void initCache()
{
cache = malloc(S*sizeof(cache_set_t));
int i;
int j;
for(i=0; i<S; i++)
{
cache[i]=malloc(E*sizeof(cache_line_t));
for(j=0;j<E;j++)
{
cache[i][j].lru=0;
cache[i][j].valid='n';
cache[i][j].tag=0;
}

}
}

/*
* freeCache - free allocated memory
*/
void free