How is 64-bit math accomplished on a 32-bit machine?

Question

If a 32-bit processor is, indeed, really only 32 bits in length, then how can math operations work on 64-bit numbers? For example:

long lngTemp1 = 1234567891         


        

Answer 1

32 bit instruction set of x86 can be used for 64 bit arithmetic, see Extended Precision Multiplication.