Floating point math in kernel interrupt -- am I doing this right?

Roger Larsson roger.larsson at norran.net
Mon Feb 6 19:41:07 EST 2006


On söndag 05 februari 2006 20.40, Jeremy Friesner wrote:
> If I disable the saving and restoring of the FPU registers 
> entirely, they don't seem to occur at all (at least within the bounds of my
> testing so far -- 15+ hours).
Is this with full mix?

Then I would really suspect the save/restore code.
Saving and restoring floating point state can be very tricky.
Do try to find an example in the manual (or possibly in the kernel itself - 
context switch code)

Until this works reliably there is no point in looking for other error 
sources.  You could also try to add code inside the save-resore that destroys 
all of the floating point registers to be able to spot errors.

/RogerL



More information about the Linuxppc-embedded mailing list