Interger over/under flow in C?

Is there a way to implement a portable way of detecting over and underflows in C?

Another thing, my asm code that handles this for now doesnt work either. I cant figure out why not.

asm ("overflow: "
     "xorl %eax, %eax \n"
     "jno O_Ret \n"
     "incl %eax \n"
     "O_Ret: ret\n");

nig_t fuck () {
  nig_t ass = tits + dick;
  if (overflow)
    return piss;
  if (underflow)
    return shit;
  return ass;
}
Now if i could figure out a way for this to work it would only work temporary, as i will need a portable way in the future anyway.

Any help would be appreciated.

>>35
From ISO/IEC 9899:2011,
``A computation involving unsigned operands can never overflow, because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type.''

It also states that overflow is undefined.