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From: Joerg Platte <lists@naasa.net>
Subject: Re: [Qemu-devel] fpu problems with qemu-system-sparc
Date: Fri, 19 May 2006 20:14:59 +0200
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To: qemu-devel@nongnu.org, Blue Swirl <blueswir1@hotmail.com>

Am Donnerstag, 18. Mai 2006 19:53 schrieb Blue Swirl:
> >I've checked a lot of the executed instructions in qemu and cannot fin=
d
> > any problems up to now. Does somebody else has an idea what to check?=
 The
> > test program simply adds two float variables (fadds-instruction) in a
> > loop and this crashes the program reproducible.
>
> Some instructions trap when FPU is disabled, and they shouldn't, like
> stfsr?

I've checked and changed a lot of code inside the kernel and in qemu and =
added=20
debbugging output. The crash is more or less reproducible and the program=
=20
crashes after 2-3 FPU disabled traps somewhere inside the libc init routi=
nes.=20
The FPU instructions cannot be the problem, because I disabled the trap i=
n=20
qemu and nothing crashed. Bit the trap is implemented like any other trap=
 and=20
all other traps seem to work. Since the crash is only reproducible in, le=
ts=20
say 95% of all tests, it looks like a timing problem. Unfortunately, I ha=
ve=20
no idea about qemu's timer simulation. What else can I check?

regards,
J=F6rg