STM32 ------ 處理 int64 類型數據需要注意

 

uint64_t destime, oritime, rectime, tratime;
int64_t result;

result = ((rectime-oritime) + (tratime-destime))/2;

 

 

當((rectime-oritime) + (tratime-destime))是負數的時候，result不能得到正確的數，需要寫成如下：

uint64_t destime, oritime, rectime, tratime;
int64_t result, tmp;

tmp = ((rectime-oritime) + (tratime-destime));
result = tmp/2;