麻烦优化成64位拷贝
时间: 2023-07-10 07:06:19 浏览: 43
好的,以下是优化后的64位拷贝代码:
```c++
#include <iostream>
#include <cstring>
void memcpy_64(char* dst, char* src, size_t n) {
size_t i = 0;
uint64_t* p_dst = reinterpret_cast<uint64_t*>(dst);
uint64_t* p_src = reinterpret_cast<uint64_t*>(src);
if (n >= 64) {
for (; i < n / 64; ++i) {
p_dst[0] = p_src[0];
p_dst[1] = p_src[1];
p_dst[2] = p_src[2];
p_dst[3] = p_src[3];
p_dst[4] = p_src[4];
p_dst[5] = p_src[5];
p_dst[6] = p_src[6];
p_dst[7] = p_src[7];
p_dst += 8;
p_src += 8;
}
}
for (; i < n / 8; ++i) {
*p_dst = *p_src;
p_dst += 1;
p_src += 1;
}
for (; i < n; ++i) {
*dst = *src;
dst += 1;
src += 1;
}
}
int main() {
char src[] = "1234567890";
char dst[11] = {0};
memcpy_64(dst, src, 10);
std::cout << dst << std::endl;
return 0;
}
```
该实现使用了指针运算和类型转换,将数据按照8字节(64位)进行拷贝。在数据量较大时,能够有效提高拷贝速度。