RE: [ros-dev] RE: [ros-diffs] [CVS reactos] FPU/SSE state saving ontaskswitching, FPU and SSE exception support.

[Hartmut Birr]

Hi,

>   -----Original Message-----
>  From: ros-dev-bounces(a)reactos.com 
>  [mailto:[e-mail]] On Behalf Of Anich Gregor
>  Sent: Sunday, November 21, 2004 2:47 PM
>  To: ReactOS Development List
>  Subject: Re: [ros-dev] RE: [ros-diffs] [CVS reactos] FPU/SSE 
>  state saving ontaskswitching, FPU and SSE exception support.
>  
>  The KPCR is per-processor, isnt it? 
Correct.


>   Is it possible that in a SMP system there is one CPU
> which 
>  has less features 
>  than the other (i.e. FXSR) or is it somewhere specified that 
>  you must use 
>  exactly same CPUs? 
The cpu's are the same and KiCheckFPU is called for both cpu's. I think that
the problem is NpxThread. If a thread uses the fpu and is switched between
different cpu's, the state of the fpu is only saved if an other thread uses
the fpu.


>   I will try to find out how to fix the fpu stuff on
> SMP...
>   
I've revert some parts of fpu.c to your first patch. It works now on my smp
machine. 


The current cvs tree doesn't work on a smp machine. If someone will test ros
on a smp machine, I should clean up and commit my changes in ntoskrnl and in
hal.

- Hartmut