Don Wrote: > The Intel CPU gives the correct answer, but AMD's is wrong. They should > both give the correct result.
Really? I think, the answer is neither correct nor wrong. It's approximate. If your friend's program operates on ~0x1p+40 values and critically depends on on the value of the last bit, then double precision doesn't suit his needs (on both Intel and AMD), he should take a couple of classes on computational theory and rewrite his algorithm, or use arithmetic with higher precision.
