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From: Stephen Hemminger <shemminger@linux-foundation.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] udivdi3: 64 bit divide
Date: Tue, 27 Feb 2007 13:18:40 -0800	[thread overview]
Message-ID: <20070227131840.672d6932@localhost> (raw)
In-Reply-To: <20070227122437.da27c3cd.akpm@linux-foundation.org>

On Tue, 27 Feb 2007 12:24:37 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:

> > On Mon, 26 Feb 2007 17:35:17 -0800 Stephen Hemminger <shemminger@linux-foundation.org> wrote:
> > The kernel already has several implmentations and usages of 64 by 64 
> > bit divide.
> > 
> > Although it is significantly slower, there are places that need it so
> > provide one generic version using scaling, and allow existing platform
> > versions to continue.
> 
> The reason we implement 64/32 via do_div() is, for better or for worse, to
> make people think before they use it.  And to make it stand out, and so
> that we discover places that are using it by accident, where they could use
> something cheaper.
> 
> However your implementation of the presumably even more expensive 64/64
> allows us to do 64/64 with a plain old "/" operator.
> 
> If the do_div() philosophy is any good then we should surely repeat it for
> 64/64, no?
> 

Then we should pull the existing udivdi3 implementations?

  reply	other threads:[~2007-02-27 21:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-27  1:35 Stephen Hemminger
2007-02-27 20:24 ` Andrew Morton
2007-02-27 21:18   ` Stephen Hemminger [this message]
2007-02-27 21:36     ` Andrew Morton
2007-02-27 22:24       ` Russell King
2007-02-27 22:39         ` Ian Molton
2007-02-28 22:30           ` Jan Engelhardt
2007-03-01 17:02             ` Ian Molton
2007-03-01  1:29   ` Tim Schmielau

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