memcpy_test.c

memcpy函数优化代码,使用汇编实现,可提高memcpy的实现性能.

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
#include <asm/mman.h>

#define HW_MEM1_BASE	0x23C00000
#define HW_MEM2_BASE	0x23D00000

static inline unsigned int GetTimer()
{
  struct timeval tv;
  struct timezone tz;
  gettimeofday(&tv,&tz);
  return (tv.tv_sec*1000+tv.tv_usec/1000);
}  

int main(void)
{
  int len;
  int i;
  unsigned int time1;
  float length;
  int fb = 0; 
  char *fbp1,*fbp2;
    
  fb = open("/dev/mem", O_RDWR);
  if (fb <=0)
  {
	printf("Could not open /dev/mem\n");
	return 0;
  }
    
  fbp1=(char*)mmap(0,0x100000,PROT_READ|PROT_WRITE,MAP_SHARED, fb, HW_MEM1_BASE); 
  fbp2=(char*)mmap(0,0x100000,PROT_READ|PROT_WRITE,MAP_SHARED, fb, HW_MEM2_BASE); 
  
  printf("start test\n");
  time1=GetTimer();
  for(i=0;i<50;i++)
 //	zhleememcpy(fbp1,fbp2,0x100000);
//	memcpy2(fbp1,fbp2,0x100000);  
	memcpy(fbp1,fbp2,0x100000);  
time1=GetTimer()-time1;
 printf("end test\n");
  printf("Memcpy time: %d\n",time1);
  
  close(fb);
}