Re: [Qemu-devel] fpu problems with qemu-system-sparc

[Joerg Platte]

Am Donnerstag, 18. Mai 2006 19:53 schrieb Blue Swirl:
> >I've checked a lot of the executed instructions in qemu and cannot find
> > 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 
debbugging output. The crash is more or less reproducible and the program 
crashes after 2-3 FPU disabled traps somewhere inside the libc init routines. 
The FPU instructions cannot be the problem, because I disabled the trap in 
qemu and nothing crashed. Bit the trap is implemented like any other trap and 
all other traps seem to work. Since the crash is only reproducible in, lets 
say 95% of all tests, it looks like a timing problem. Unfortunately, I have 
no idea about qemu's timer simulation. What else can I check?

regards,
Jörg