you would never write this in production...right?

int saturating_add(int u, int v)
{
    unsigned s = (unsigned)(u + v);

    // overflow test
    unsigned q = s - u;
    unsigned p = q >> 31; // if this is 1, we have an overflow

    // underflow test
    unsigned p1 = (u >> 31) & (v >> 31); // if 1, they're both < 0
    unsigned p2 = (p1 ^ (s >> 31)) & ((s >> 31) == 0); // if 1, we have an underflow

    return (int)((s & (0xFFFFFFFF + (p2 | p))) | (INT_MIN & (INT_MAX + p2)) | (INT_MAX & (INT_MIN - p)));
}