kruger@16bits.dec.com (Bear with me) (03/04/88)
Lawrence Crowl writes that there is no easy way to tell when you've really created an overflow condition in a partial computation. While this may be true in current architectures, it does not have to be. There are two cases: x*5 == x << 2 + x in which you want to OR the overflow condition, and x*7 == x << 3 - x in which you want to XOR the overflows at each step. Even with multiple levels of doing this, you can keep this methodology and effectively keep track of overflow -- given appropriate (and minimal) hardware support. dov