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Re: K6-II+, persistent strange test results of glibc-2.2.3


On 28 Apr 2001, Ulrich Drepper wrote:

> Byeong-ryeol Kim <jinbo21@hananet.net> writes:
>
> >  is:         -2.48292386531829833984e-01  -0x1.fc80b800000000000000p-3
> >  should be:  -2.51362651586532592773e-01  -0x1.01653600000000000000p-2
> >  difference:  3.07026505470275878906e-03   0x1.926d0000000000000000p-9
> >  ulp       :  103021.0000
> >  max.ulp   :  1.0000
> > Maximal error of `yn'
> >  is      :  103021.0000 ulp
> >  accepted:  3.0000 ulp
>
> This normally would suggest that the compiler is broken and you should
> use a better one.
....

I'll try to test with latest gcc 3.1 pre-release, later.

> If you say that running the same binary produces different results
> (and since this is not the case anywhere else) it's either a kernel or
> a CPU problem.  AMD's FPU is lousy and I wouldn't be surprised at all.
...
If these problems were related with kernel, which version of kernel
would be adequate for glibc-2.2.3?

Yes, I know, AMD CPUs prior to Athlons have deficiency in FPU-intensive
work, and I admit my CPU has serious problem, prepared to give up this
CPU.
But, why problems I mentioned in previous mail appear these
days(2.2.3preX era), are newly added math functions revealing the
workarounded CPU problems explicitly?
If those were due to the deficiency of FPU of AMD CPUs, is this
statement interpretable that AMD CPUs(though not all) are not adequate
for FPU-intensive work or development platform of FPU-intensive programs?
If so, How about Athlon or Duron family?



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