Integral promotion.

[warawut]

I have some doubt about the integral promotion whether how integral promotion's rule perform with the unsuffixed constant (hexadecimal).
Example:

16bit ECU
0xffff -----> Will it promote to \"int\" or \"unsigned int\"?
0xffffffff -----> Will it promote to \"int\" or \"unsigned int\"?

32bit ECU
0xffff -----> Will it promote to \"int\" or \"unsigned int\"?
0xffffffff -----> Will it promote to \"int\" or \"unsigned int\"?

Who know how does it perform with hexadecimal.
Please kindly give me the answer.

Thanks in advance,
Warawut.