RE: [ros-dev] Save FPU on task switch/SSE support

[Hartmut Birr]

>   -----Original Message-----
>  From: ros-dev-bounces(a)reactos.com 
>  [mailto:[e-mail]] On Behalf Of Alex Ionescu
>  Sent: Friday, October 08, 2004 11:48 PM
>  To: ReactOS Development List
>  Subject: Re: [ros-dev] Save FPU on task switch/SSE support
>  
>  
>  Hi,
>  
>  As I added the KPRCB I noticed the last field is called 
>  NpxSaveArea and 
>  contains the last FPU/SSE state, iirc.
>  
>  You might want to save it there...but what troubles me is 
>  that the KPRCB 
>  is a CPU-wide structure, not thread-limited.
>   
For each thread we need two save areas (user and kernel mode) because win32k
and free type are using the fpu. This is different to Windows. On a callback
from kernel to user mode we need more than this two save areas for a thread.
The save area in the kpcr structure is for entering/leaving the standby
mode.

- Hartmut