The FPU register aren't always saved out to memory on context switches, so
the IPI_CONTEXT_SAVE makes sure the in memory values are up to date. With
Altivec/SPE, we aren't as fully optimized and the in memory values are always
in sync with the register values, so the IPI_CONTEXT_SAVE doesn't have to
do anything.

	Brian

On Wed, Apr 08, 2009 at 09:23:24PM -0400, Neil Schellenberger wrote:
> Can anyone explain for me why IPI_CONTEXT_SAVE only saves the FPU context and not the alt context (e.g. Altivec or 
SPE)?  Is it because that's already handled in some other way?
> 
> 
> _______________________________________________
> OSTech
> http://community.qnx.com/sf/go/post26475
> 

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Brian Stecher (bstecher@qnx.com)        QNX Software Systems
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