Phobos unit testing uncovers a CPU bug

[Kagamin]

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.