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Re: FPU emulator unsafe for SMP?

To: Ralf Baechle <>
Subject: Re: FPU emulator unsafe for SMP?
From: "Maciej W. Rozycki" <>
Date: Wed, 20 Feb 2002 15:46:32 +0100 (MET)
Cc: Jun Sun <>, "Kevin D. Kissell" <>,
In-reply-to: <>
Organization: Technical University of Gdansk
On Wed, 20 Feb 2002, Ralf Baechle wrote:

> The context register is actually intended to be used for indexing a flat
> 4mb array of pagetables on a 32-bit processor.  It's a bit ill-defined
> on R4000-class processors as it assumes a size of 8 bytes per pte, so
> cannot be used in the Linux/MIPS kernel without shifting bits around.

 Ill???  I think someone was just longsighted enough not to limit PTEs to
38-bit physical addresses.  A shift costs a single cycle if we want to
save memory. 

+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+        e-mail:, PGP key available        +

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