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Subject: Re: [Cbe-oss-dev] Cell and new CPU feature bits
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Andrew Pinski <pinskia@physics.uc.edu>
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Date: Fri, 26 May 2006 16:19:53 +1000
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Cc: Olof Johansson <olof@lixom.net>,
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> > I'm assuming you mean the instructions described under "AltiVec Memory
> > Bandwidth Management" in secion 5.2 of the Altivec PEM -- dst, dstt,
> > dstst, dss and dssall?
> 
> They are nops on the Cell though.  They are also microcoded on the 970.

It's still useful to have a way to inform userland of their absence (or
inefficency).

> > If you're referring to the extended dcbt that includes streaming hints
> > (as documented in the 64-bit PEM, but not in PPC book2 2.02), then a
> > separate bit is likely needed -- obviously at least 970 seems to
> > implement them.
> 
> Yes they are implemented on the 970.