linux-mips
[Top] [All Lists]

Re: MIPS32 patches breaking DecStation

To: "Ralf Baechle" <ralf@oss.sgi.com>
Subject: Re: MIPS32 patches breaking DecStation
From: "Kevin D. Kissell" <kevink@mips.com>
Date: Tue, 9 Jan 2001 21:33:12 +0100
Cc: "Harald Koerfgen" <Harald.Koerfgen@home.ivm.de>, <linux-mips@oss.sgi.com>
References: <20010109095438.A10683@paradigm.rfc822.org> <XFMail.010109181100.Harald.Koerfgen@home.ivm.de> <20010109162835.B4232@bacchus.dhis.org> <019901c07a72$94d19f00$0deca8c0@Ulysses> <20010109175416.A5383@bacchus.dhis.org>
Sender: owner-linux-mips@oss.sgi.com
> > Yes, it's cute, but it relies on accidents of implementation to work,
> > and could easily fail on other CPUs otherwise compatible with
> > the R4000.  In principle, such a branch might incur no delay at
> > all on an advanced 64-bit processor.  By all means, use it for
> > the specific cases of the CPUs on which it is known to work,
> > but it should not be used in "default" MIPS CP0 handlers.
> 
> This behaviour of the R4000 branch is documented in the R4000 manual's
> description of the pipeline.

Yes, yes, like I said, use it whenever you see an R4000 PrID
if you like.  Just don't use it as the handler installed for a PrID
not otherwise known to the kernel.

            Kevin K.


<Prev in Thread] Current Thread [Next in Thread>