How to store a 64 bit integer in two 32 bit integers and convert back again

Question

I\'m pretty sure its just a matter of some bitwise operations, I\'m just not entirely sure of exactly what I should be doing, and all searches return back \"64 bit vs 32 bit

Answer 1

The basic method is as follows:

uint64_t int64;
uint32_t int32_1, int32_2;

int32_1 = int64 & 0xFFFFFFFF;
int32_2 = (int64 & (0xFFFFFFFF << 32) ) >> 32;

// ...

int64 = int32_1 | (int32_2 << 32);

Note that your integers must be unsigned; or the operations are undefined.