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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Joe Perches <joe@perches.com>
Cc: Stratos Karafotis <stratosk@semaphore.gr>,
	Dirk Brandewie <dirk.brandewie@gmail.com>,
	dirk.j.brandewie@intel.com,
	Viresh Kumar <viresh.kumar@linaro.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/7] cpufreq: intel_pstate: Trivial code cleanup
Date: Wed, 11 Jun 2014 02:23:27 +0200	[thread overview]
Message-ID: <2859027.TirvIA2s2c@vostro.rjw.lan> (raw)
In-Reply-To: <1402435605.4082.3.camel@joe-AO725>

On Tuesday, June 10, 2014 02:26:45 PM Joe Perches wrote:
> On Tue, 2014-06-10 at 23:38 +0200, Rafael J. Wysocki wrote:
> 
> > > > is.  And the result of (a * 100) / b may generally be different from
> > > > a * 100 / b for integers (if the division is carried out first).
> > > 
> > > I thought that (a * 100) / b is always equivalent to a * 100 / b.
> > 
> > I'm not actually sure if that's guaranteed by C standards.
> 
> It is.  left to right, same precedence.
> 
> > It surely
> > wasn't some time ago (when there was no formal C standard).
> 
> c89 is 25 years ago now.

Apparently, I'm old.

> > Either way, in my opinion it's better to put the parens into the expression
> > in this particular case to clearly state the intention.
> 
> I don't think so.

Of course, you're free to disagree, but I guess you'll admit that
a * b / c is generally different from b / c * a and if you see something
like this it is hard to say at first sight whether or not this is intentional
or an expression ordering bug.

Rafael


  reply	other threads:[~2014-06-11  0:06 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-09 21:01 [PATCH 6/7] cpufreq: intel_pstate: Trivial code cleanup Stratos Karafotis
2014-06-09 21:22 ` Joe Perches
2014-06-10 14:43   ` Stratos Karafotis
2014-06-10 15:12 ` Dirk Brandewie
2014-06-10 15:31   ` Rafael J. Wysocki
2014-06-10 17:26     ` Dirk Brandewie
2014-06-10 20:17       ` Rafael J. Wysocki
2014-06-10 20:14         ` Stratos Karafotis
2014-06-10 20:43           ` Rafael J. Wysocki
2014-06-10 21:02             ` Stratos Karafotis
2014-06-10 21:38               ` Rafael J. Wysocki
2014-06-10 21:26                 ` Joe Perches
2014-06-11  0:23                   ` Rafael J. Wysocki [this message]
2014-06-11  1:41                     ` Joe Perches
2014-06-10 21:35                 ` Stratos Karafotis
2014-06-11  0:24                   ` Rafael J. Wysocki

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