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Re: Question about r4k_clear_page_xxx()

To: Rani Assaf <rani@paname.org>
Subject: Re: Question about r4k_clear_page_xxx()
From: Ralf Baechle <ralf@oss.sgi.com>
Date: Thu, 11 Apr 2002 22:04:01 -0700
Cc: linux-mips@oss.sgi.com
In-reply-to: <20020410041408.G23127@paname.org>; from rani@paname.org on Wed, Apr 10, 2002 at 04:14:08AM +0200
References: <20020410041408.G23127@paname.org>
Sender: owner-linux-mips@oss.sgi.com
User-agent: Mutt/1.2.5.1i
On Wed, Apr 10, 2002 at 04:14:08AM +0200, Rani Assaf wrote:

> I was cleaning  duplicate code between my port of  IDT RC32355 and the
> current tree. I want to use r4k_clear_page_d16() but the function uses
> store double (sd) which is not available on this processor.
> 
> What's the reason for having r4k_clear_page_xxx() use store double and
> not r4k_copy_page_xxx()??

The 32-bit kernel doesn't save or restore the upper 32-bits of general
purpose registers.  Therefore 64-bit stores can only be used with the
$zero register.

  Ralf

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