RE: [ros-dev] Kernel-mode stack layout (FPU save area, trap frames, etc.)

[Hartmut Birr]

Hi,    

I think we need two floating save areas, one for user mode and one for
kernel mode. The area for kernel mode is necessary because win32k and
freetype are using the fpu. The kernel mode area is not necessary if we
protect some function in win32k with
KeSaveFloatingPointState/KeRestoreFloatingPointState. The start of the areas
should be calculate as a offset from the top of the kernel stack and not as
offset from the user mode trap frame. The state of the fpu must be saved on
a thread switch and if the fpu was used. At this point the start of the user
mode trap frame is only known as an offset from the top of the stack.    

- Hartmut


>   -----Original Message-----
>  From: ros-dev-bounces(a)reactos.com 
>  [mailto:[e-mail]] On Behalf Of KJK::Hyperion
>  Sent: Wednesday, October 13, 2004 8:13 AM
>  To: ros-dev(a)reactos.com
>  Subject: [ros-dev] Kernel-mode stack layout (FPU save area, 
>  trap frames,etc.)
>  
>  
>  I've finally taken the time to write it all down:
>  
>  <http://mok.lvcm.com/cgi-bin/reactos/roswiki?KernelModeStackLayout>
>  
>  Let me know if you see any mistakes or omissions
>  
>