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From: juli mallett <jmallett@FreeBSD.org>
To: Ralf Baechle <ralf@linux-mips.org>
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cc: Gheorghe Ardelean <ardelean@ww.uni-erlangen.de>
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Subject: Re: Some MIPS status goodies.
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* Ralf Baechle <ralf@linux-mips.org> [ Date: 2004-06-10 ]
	[ w.r.t. Re: Some MIPS status goodies. ]
> On Wed, Jun 09, 2004 at 11:07:12PM -1000, juli mallett wrote:
> 
> > R10K and IP28 support are probably a ways away, but I'm interested
> > in supporting these systems and more.  Right now it's easiest to start
> > with the, much simpler, R4400 Indigo2 I have here, and get a good base
> > of this stuff, then move into supporting the more modern and complex
> > CPUs and machines - but be assured I am taking them into account!
> 
> R10000 in non-coherent systems (Indigo 2 R10000, O2) is a rather hard to
> use processor due to unwanted behaviour of speculative execution that
> leads to memory corruption.  The workarounds are fairly complex; efficient
> solutions involve compiler modifications.

Yeah, I read about the compiler mods SGI had to make, with accessing
the stack as a barrier...  It sounded like that was only for the
kernel though, yeah?

> That said, the R10000's is resolving all hazards in hardware and does
> almost the entire coherency in software so in a saner system such as
> the Origin it's a breeze.

Right.

juli.
-- 
juli mallett.  jmallett@freebsd.org.  adrift in the pacific.