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Re: glibc 2.3 on linux-mips


On Mon, Oct 21, 2002 at 04:55:31PM +0200, Ralf Baechle wrote:
[..snip..] 
> > which additionally masks out the condition bit 23 - note that the other
> > condition bits (25-31) are masked out too?
> 
> The value of _FPU_RESERVED reflects some particular MIPS CPU; I think I
> choose the R4600 back in the dark ages when the universe was formed ;-)
Hmmm...but this has 23 as condition bit too.

> 
> As different CPU declare reserve different bits in fcr31 I'm not sure which
> bits we should set in _FPU_RESERVED.  Two possibilities, the bits that are
> reserved on all FPUs or those that are reserved on the lowest end supported
> CPU?
If I understand things correctly 25-31 are only condition bits on
MIPS IV or newer CPUs, so it's fine to mask them.

> 
> Imho test-fpucw.c as well; it assumes that reserved bits have to be
> zero will fail on anything that doesn't fulfill that assumption.  That hold
> for MIPS FPUs but probably not on all FPUs of all architectures out there.
Hmm...no. If I understand things correctly it doesn't assume anything
about reserved bits - that why it masks them out - that's why I actually
think we should mask bit 23.
Regards, 
 -- Guido


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