How to do unsigned saturating addition in C?

Question

What is the best (cleanest, most efficient) way to write saturating addition in C?

The function or macro should add two unsigned inputs (need both 16- and 32-bit ver

Answer 1

I suppose, the best way for x86 is to use inline assembler to check overflow flag after addition. Something like:

add eax, ebx
jno @@1
or eax, 0FFFFFFFFh
@@1:
.......

It's not very portable, but IMHO the most efficient way.