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Subject: Re: [RFC][PATCH] Faster generic_fls
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>,
       dphillips@sistina.com,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Date: 30 Apr 2003 23:47:53 +0100
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On Iau, 2003-05-01 at 00:41, Linus Torvalds wrote:
> On 30 Apr 2003, Alan Cox wrote:
> > 
> > It ought to be basically the same as ffs because if I remember rightly 
> > 
> > ffs(x^(x-1)) == fls(x)
> 
> So did anybody time this? ffs() we have hardware support for on x86, and 
> it's even reasonably efficient on some CPU's .. So this _should_ beat all 
> new-comers, and obviously some people already have benchmark programs 
> ready and willing..

Unfortunately on digging up my notes it seems I got ffs/fls backwards so it doesnt
help us a great deal.