Developer Forum

by **Luis Vacca** » Sun, 16 Oct 2005 16:51:09

Hi all,

I know that in Kernel mode if I want to use the FPU I have to call
KeSave/RestoreFloatingPointState, my question is: does Windows XP take care
of that when I'm in user mode? I'm doing a routine that uses all 8 registers
of the FPU so I need to know how windows deals with the FPU in user mode.

regards
--
Luis Vaccaro

by **Tim Robert** » Mon, 17 Oct 2005 07:17:35

Windows will save and restore the floating point state on a context switch
to a different user-mode thread. As long as all kernel drivers follow the
rule, the FPU state will always be as you left it.
--
- Tim Roberts, XXXX@XXXXX.COM
Providenza & Boekelheide, Inc.

by **Luis Vacca** » Mon, 17 Oct 2005 17:06:31

ok, thanks!

--
Luis Vaccaro

care
registers

Developer Forum

[may be OT] FPU user mode

[may be OT] FPU user mode

[may be OT] FPU user mode

[may be OT] FPU user mode