From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-parisc-linux@dsl2.external.hp.com>
Date: Fri, 5 Sep 2003 13:29:27 -0600
From: Grant Grundler <grundler@parisc-linux.org>
To: Joel Soete <joel.soete@tiscali.be>
Cc: parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] a fast fls also for 2.6?
Message-ID: <20030905192927.GD10216@dsl2.external.hp.com>
References: <3F58838A.9010203@tiscali.be> <3F5888F3.5060609@tiscali.be> <20030905182621.GC10216@dsl2.external.hp.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <20030905182621.GC10216@dsl2.external.hp.com>
Sender: parisc-linux-admin@lists.parisc-linux.org
Errors-To: parisc-linux-admin@lists.parisc-linux.org
List-Help: <mailto:parisc-linux-request@lists.parisc-linux.org?subject=help>
List-Post: <mailto:parisc-linux@lists.parisc-linux.org>
List-Subscribe: <http://lists.parisc-linux.org/mailman/listinfo/parisc-linux>,
	<mailto:parisc-linux-request@lists.parisc-linux.org?subject=subscribe>
List-Id: parisc-linux developers list <parisc-linux.lists.parisc-linux.org>
List-Unsubscribe: <http://lists.parisc-linux.org/mailman/listinfo/parisc-linux>,
	<mailto:parisc-linux-request@lists.parisc-linux.org?subject=unsubscribe>
List-Archive: <http://lists.parisc-linux.org/pipermail/parisc-linux/>

On Fri, Sep 05, 2003 at 12:26:21PM -0600, Grant Grundler wrote:
> > Without any remark, I don't know if you could also be interested to 
> > include it in 2.6.
> 
> no - becuase fls() and ffs() return the same values for given input.
> (I see comments in include/asm-ppc/bitops.h to that effect).

James Bottomley privately corrected me. fls() != ffs().
fls() returns most significant bit set.

The examples provided:
	* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.

have the same value for ffs() and fls(). I didn't read the rest.
Good examples for showing bit numbering though.

I'll work on adding 64-bit support to your __fls() and commit that.

sorry for the confusion,
grant