Question

Does C sign extend constants or zero extend them?
For example:

int a = 123 & 0x3

is the 0x3 zero extend or sign extended?
Also in general, what things are zero extended in C and what are sign extended?

Thanks!

Answer 1

The C standard does not mandate whether the implementation uses 2’s complement, 1’s complement, or something else. So the representation of negative values is not mandated either.

However, in your particular case, 0x3 is a positive value, so sign-extension and zero-extension are the same thing!