[JdeBP]

It's not as simple as that. I had a C library using 64-bit time_t on 32-bit CPUs back in the early 1990s. 32-bit CPUs are not incapable of doing 64-bit arithmetic. You cannot infer the bitness of time_t from the bitness of the CPU.

[DanielShir]

Really? So how does a 32 bit CPU run 64 bit code?

[Roshie5u]

It doesn't run 64bit code but that has nothing to do with handling 64bit numbers. Compiler just generates more instructions (and the execution is slower). Example for multiplication: https://godbolt.org/g/m1t4NC