linux-kernel - Re: [PATCH] udivdi3: 64 bit divide

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Date:	Tue, 27 Feb 2007 13:18:40 -0800
From:	Stephen Hemminger <shemminger@...ux-foundation.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] udivdi3: 64 bit divide

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

> > On Mon, 26 Feb 2007 17:35:17 -0800 Stephen Hemminger <shemminger@...ux-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?
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