From: Lee Revell <rlrevell@joe-job.com>
To: Paulo Marques <pmarques@grupopie.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Bernd Petrovitsch <bernd@firmix.at>,
Andrew Morton <akpm@osdl.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Grant Coady <lkml@dodo.com.au>,
Jan Engelhardt <jengelh@linux01.gwdg.de>,
Puneet Vyas <vyas.puneet@gmail.com>
Subject: Re: xor as a lazy comparison
Date: Mon, 25 Jul 2005 15:25:35 -0400 [thread overview]
Message-ID: <1122319535.1472.17.camel@mindpipe> (raw)
In-Reply-To: <42E53C25.10100@grupopie.com>
On Mon, 2005-07-25 at 20:23 +0100, Paulo Marques wrote:
> Lee Revell wrote:
> > On Mon, 2005-07-25 at 13:55 -0400, Steven Rostedt wrote:
> >
> >>Doesn't matter. The cycles saved for old compilers is not rational to
> >>have obfuscated code.
> >
> > Where do we draw the line with this? Is x *= 2 preferable to x <<= 2 as
> > well?
>
> I guess this depends on what you logically want to do. If the problem
> requires you to shift some value N bits, then you should use a shift
> operation.
>
> If what you want is to multiply a value by a certain ammount, you should
> just use a multiplication.
>
> Using a shift to perform the multiplication should be left to the
> compiler IMHO.
>
> The proof that the shift is not so clear is that even you got the shift
> wrong in your own example ;)
>
Yeah, that was going to be my point, but I made it inadvertently before
I even got that far...
Lee
next prev parent reply other threads:[~2005-07-25 19:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-24 16:40 xor as a lazy comparison Jan Engelhardt
2005-07-24 20:07 ` Grant Coady
2005-07-24 21:43 ` Jan Engelhardt
2005-07-24 22:15 ` Puneet Vyas
2005-07-25 8:57 ` Bernd Petrovitsch
2005-07-25 17:55 ` Steven Rostedt
2005-07-25 19:10 ` Lee Revell
2005-07-25 19:16 ` Philippe Troin
2005-07-25 19:18 ` Lee Revell
2005-07-26 6:07 ` Jan Engelhardt
2005-07-26 8:30 ` Bernd Petrovitsch
2005-07-25 19:24 ` Steven Rostedt
2005-07-25 19:27 ` Lee Revell
2005-07-25 19:23 ` Paulo Marques
2005-07-25 19:25 ` Lee Revell [this message]
2005-07-25 20:24 ` Bill Davidsen
2005-07-25 18:00 ` [PATCH] make signal.c more readable (was: Re: xor as a lazy comparison) Steven Rostedt
-- strict thread matches above, loose matches on Subject: below --
2005-07-27 18:24 xor as a lazy comparison Clayton Weaver
2005-07-27 19:58 ` linux-os (Dick Johnson)
2005-07-28 0:04 ` Grant Coady
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