#include <stdlib.h>
#include <stdio.h>
void add64(unsigned int add1,unsigned int add2,unsigned int *pSumHigh,unsigned int *pSumLow)
{
*pSumLow = add1 + add2;
if(*pSumLow < add1 || *pSumHigh < add2)
{
*pSumHigh = 1;
}
else
{
*pSumHigh = 0;
}
printf("h is 0x%x l is 0x%x\n",*pSumHigh,*pSumLow);
}
int main()
{
unsigned h,l;
add64(0xffffff00, 0x000000ff,&h,&l);
printf("h is 0x%x l is 0x%x\n",h,l);
add64(0xffffffff, 0x00000001,&h,&l);
printf("h is 0x%x l is 0x%x\n",h,l);
add64(0xffffff00, 0x000002ff,&h,&l);
printf("h is 0x%x l is 0x%x\n",h,l);
add64(0x00000001, 0x00000001,&h,&l);
printf("h is 0x%x l is 0x%x\n",h,l);
return 0;
}
运行结果：root@quieter:~# ./a.out
h is 0x0 l is 0xffffffff
h is 0x0 l is 0xffffffff
h is 0x1 l is 0x0
h is 0x1 l is 0x0
h is 0x1 l is 0x1ff
h is 0x1 l is 0x1ff
h is 0x0 l is 0x2
h is 0x0 l is 0x2
转自：http://blog.csdn.net/ysdaniel/article/details/6774329