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Re: K6-II+, persistent strange test results of glibc-2.2.3
- To: Ulrich Drepper <drepper at redhat dot com>
- Subject: Re: K6-II+, persistent strange test results of glibc-2.2.3
- From: Stephen L Moshier <moshier at mediaone dot net>
- Date: Sat, 28 Apr 2001 17:35:49 -0400 (EDT)
- cc: libc-alpha at sourceware dot cygnus dot com
- Reply-To: moshier at moshier dot ne dot mediaone dot net
>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
>
> AMD's FPU is lousy and I wouldn't be surprised at all
These errors (I have seen them too, previously) go away for me
if they are tested by a separate little test program of the same
particular calculation. Anyhow on the AMD K6 I got several
segmentation faults during the build of 2.2.3 and no errors on make
check.
Maybe this is a compiler problem of some kind; I would be inclined to
try an older model of compiler, rather than a newer one. But I have
trouble thinking of an ordinary miscompilation that would affect AMD
processors and not Intel.
To find out if it is a hardware problem you must be ready to exchange
everything: CPU, memory, motherboard, ... Maybe it is easier just to
ask if anybody has seen an AMD machine that does not fail.