Re: compiler bug in gcc version 2.8.1 (Tornado1) for PPC corrupts floationg point constants?

[Kay-Uwe Kasemir <kasemirk@ornl.gov>]

Hello:

Having learned the hard way,
I'm now quite aware of the VX_FP_TASK option
for vxWorks' taskCreate().

To be save inside ISR code, no matter how the compiler
optimizes your non-floating point code:
Are there vxWorks subroutines or asm(...)-type macros that allows
me to save/restore the FP registers?
If not, does anybody know the asm(..) lines that would work on
a PPC CPU?

Thanks,
-Kay

On Feb 9, 2005, at 13:02, J. Frederick Bartlett wrote:
> Jeff,
> ...we did discover during the investigation that a FP register's 
> contents was being altered during the execution of the driver's 
> interrupt service routine (ISR) and that, even though no FP operations 
> were being performed in the ISR, the compiler optimization level that 
> we were using caused the FP registers to be used to store temporary 
> values.
> > > ...Jeff Hill wrote:
> > > > interrupt service routines as, on vxWorks, the FP
> > > > register contents are not saved / restored when
> > > entering
> > >
> > > > / exiting interrupt context. The driver must do this
> > > > manually if it finds a need to use FP in its ISR.