Phobos unit testing uncovers a CPU bug

[Don]

Kagamin wrote:
> Don Wrote:
> 
>> The great tragedy was that an early AMD processor gave much accurate sin 
>> and cos than the 387. But, people complained that it was different from 
>> Intel! So, their next processor duplicated Intel's hopelessly wrong trig 
>> functions.
> 
> The same question goes to you. Why do you call this bug?

The Intel CPU gives the correct answer, but AMD's is wrong. They should 
both give the correct result.