Alternative math libraries

[Stephen L Moshier]

>> I was sure that linux glibc libm on Intel uses the actual x86
>> trigometric instructions to implement these routines.
>> 
>> Later,
>> David S. Miller
>> davem@redhat.com
>
>That's correct.  Those hardware instructions only give the correct
>answer when |x|<2^62.

No, that's not right.  More marketing doubletalk.  It's worse than
that.  The incorrect answer threshold, for absolute measure, is about 2^18
for double precision and 2^47 for single precision.  2^62 is the
*totally* wrong answer threshold, where the error approaches 100%
and the hardware raises a flag.