From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Christoph Lameter <cl@linux.com>
Cc: Daniel Borkmann <dborkman@redhat.com>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
Austin S Hemmelgarn <ahferroin7@gmail.com>,
Jesse Gross <jesse@nicira.com>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Matt Mackall <mpm@selenic.com>, Pekka Enberg <penberg@kernel.org>,
Andy Gospodarek <andy@greyhouse.net>,
Veaceslav Falico <vfalico@redhat.com>,
Jay Vosburgh <fubar@us.ibm.com>,
Jakub Zawadzki <darkjames-ws@darkjames.pl>
Subject: Re: [PATCH net-next 2/2] reciprocal_divide: correction/update of the algorithm
Date: Thu, 16 Jan 2014 18:24:06 +0100 [thread overview]
Message-ID: <20140116172406.GA17529@order.stressinduktion.org> (raw)
In-Reply-To: <alpine.DEB.2.10.1401161036110.29778@nuc>
On Thu, Jan 16, 2014 at 10:37:37AM -0600, Christoph Lameter wrote:
> On Thu, 16 Jan 2014, Daniel Borkmann wrote:
>
> > - * or else the performance is slower than a normal divide.
> > - */
> > -extern u32 reciprocal_value(u32 B);
> > +struct reciprocal_value {
> > + u32 m;
> > + u8 sh1, sh2;
> > +};
> >
> > +#define RECIPROCAL_VALUE_RESULT_TO_ZERO ((struct reciprocal_value){.sh1 = 32})
> >
> > -static inline u32 reciprocal_divide(u32 A, u32 R)
> > +struct reciprocal_value reciprocal_value(u32 d);
>
> A function that returns a struct? That works? Which gcc versions support
> it?
Sure, that works and I actually like it. This is supported by the c standard,
but please don't ask me since which one. ;)
Greetings,
Hannes
next prev parent reply other threads:[~2014-01-16 17:24 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-15 23:23 [PATCH net-next 0/2] reciprocal_divide updates Daniel Borkmann
2014-01-15 23:23 ` [PATCH net-next 1/2] random32: add prandom_u32_lt_N and convert "misuses" of reciprocal_divide Daniel Borkmann
2014-01-16 0:29 ` Joe Perches
2014-01-16 9:22 ` Daniel Borkmann
2014-01-16 3:14 ` Eric Dumazet
2014-01-16 9:28 ` David Laight
2014-01-16 9:30 ` Daniel Borkmann
2014-01-15 23:23 ` [PATCH net-next 2/2] reciprocal_divide: correction/update of the algorithm Daniel Borkmann
2014-01-16 0:17 ` Ben Hutchings
2014-01-16 0:46 ` Hannes Frederic Sowa
2014-01-16 3:07 ` Eric Dumazet
2014-01-16 10:26 ` Hannes Frederic Sowa
2014-01-16 16:37 ` Christoph Lameter
2014-01-16 17:24 ` Hannes Frederic Sowa [this message]
2014-01-17 10:05 ` David Laight
2014-01-16 18:50 ` Ben Hutchings
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