> Very true... Ideal case would be if the FPE core could tell us if the context
> has changed.. Hmm Nope that is not good enough.
> I guess we need to turn the FPE/FPA off on a context switch and re-enable it
> on the first FP instruction.

Like is done in most (all?) other ports and in any U*X port I've ever seen.

> Not sure how friendly the ARM FPE/FPA is when you try and do this ...
> 
> >Hmm, I haven't looked at the code, but what is the problem to save/restore the
> >exception bits when you already have to save/restore the registers anyway?
> >Surely the FP registers are much more stuff than the exception bits, aren't
> >they?
> 
> Yes in theory the control register is just an extra word. The problem is the
> that the save/restore of the context is done by the FPE core and the contexts
> do not appear to change the FPCR. Certain save/load context routines do not
> include the FPCR. This means that the mcr/mrc instructions for coproc 1 would
> be needed to extract the information out of the core. This is the time
> consuming bit ...

Hmm, I don't know whether I get this. Are you saying that the FPE core has an
entry point to be called on context switch that saves/restores registers, but
doesn't do so for the FPCR? This would be very strange, I think.
--
ws@TooLs.DE     (Wolfgang Solfrank, TooLs GmbH) 	+49-228-985800