From: Joe Perches <joe@perches.com>
To: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH] - trivial - Improve appletalk checksum calculation
Date: Mon, 22 Oct 2007 20:39:59 -0700 [thread overview]
Message-ID: <1193110799.5132.48.camel@localhost> (raw)
In-Reply-To: <20071022203052.23725719@freepuppy.rosehill>
On Mon, 2007-10-22 at 20:30 -0700, Stephen Hemminger wrote:
> > Corrected fast code is:
> >
> > while (len--) {
> > sum += *data++;
> > sum <<= 1;
> > sum = (((sum & 0x10000) >> 16) + sum) & 0xffff;
> > }
> >
> > At least it is correct on the standalone random data test, and the
> > new code is 30% faster for the cached memory case (13.7 clks/byte vs 18
> > clks/byte).
> Your code looks different...
Both are 16 bit rotate lefts.
Which looks clearer?
prev parent reply other threads:[~2007-10-23 3:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-22 19:36 [PATCH] - trivial - Improve appletalk checksum calculation Joe Perches
2007-10-23 0:35 ` David Miller
2007-10-23 1:36 ` Joe Perches
2007-10-23 1:43 ` David Miller
2007-10-23 1:53 ` Joe Perches
2007-10-23 3:51 ` Herbert Xu
2007-10-28 20:18 ` Urs Thuermann
2007-10-28 21:01 ` Joe Perches
2007-10-29 2:40 ` Joe Perches
2007-10-23 3:30 ` Stephen Hemminger
2007-10-23 3:39 ` Joe Perches [this message]
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