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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Jonathan Cameron <jic23@cam.ac.uk>
Cc: guenter.roeck@ericsson.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
	"linus.ml.walleij@gmail.com" <linus.ml.walleij@gmail.com>,
	"zdevai@gmail.com" <zdevai@gmail.com>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"broonie@opensource.wolfsonmicro.com" 
	<broonie@opensource.wolfsonmicro.com>,
	"gregkh@suse.de" <gregkh@suse.de>,
	"lm-sensors@lm-sensors.org" <lm-sensors@lm-sensors.org>,
	"khali@linux-fr.org" <khali@linux-fr.org>,
	"thomas.petazzoni@free-electrons.com" 
	<thomas.petazzoni@free-electrons.com>,
	"maxime.ripard@free-electrons.com"
	<maxime.ripard@free-electrons.com>
Subject: Re: [PATCH 5/6] IIO:hwmon interface client driver.
Date: Mon, 24 Oct 2011 20:33:42 +0100	[thread overview]
Message-ID: <20111024193342.GA27011@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <4EA58B39.8030608@cam.ac.uk>

On Mon, Oct 24, 2011 at 04:58:49PM +0100, Jonathan Cameron wrote:
> On 10/24/11 16:39, Guenter Roeck wrote:
> > Is div_s64 really necessary, or would
> > 
> > 		result = (long)val * (long)scaleint +
> > 			DIV_ROUND_CLOSEST((s64)val * (s64)scalepart,
> > 					 1000000000LL);
> > 
> > work as well ?
> Not if you want it to compile on arm v5 by the look of it.
> 
> ERROR: "__aeabi_ldivmod" [drivers/staging/iio/iio_hwmon.ko] undefined!

You know, div64 is there to deal with the case of _sanely_ dividing
a 64-bit number by a 32-bit number - there should be absolutely no
question about _not_ using it if that's the operation you are wanting
to perform.

Expecting gcc to do a better job without using div64 is just asking for
bad code on 32-bit platforms.

  parent reply	other threads:[~2011-10-24 19:33 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-20  9:33 [RFC V3 PATCH 0/6] IIO in kernel interfaces Jonathan Cameron
2011-10-20  9:33 ` [PATCH 1/6] IIO: core: add datasheet_name to chan_spec Jonathan Cameron
2011-10-20  9:33 ` [PATCH 2/6] IIO:ADC:max1363 add datasheet_name entries Jonathan Cameron
2011-10-20  9:33 ` [PATCH 3/6] IIO:CORE: put defs needed by inkern and userspace interfaces into chan_spec.h Jonathan Cameron
2011-10-20  9:33 ` [PATCH 4/6] IIO:CORE add in kernel interface mapping and getting IIO channels Jonathan Cameron
2011-10-20  9:33 ` [PATCH 5/6] IIO:hwmon interface client driver Jonathan Cameron
2011-10-20 15:12   ` Guenter Roeck
2011-10-20 15:30     ` Jonathan Cameron
2011-10-24 10:09       ` Jonathan Cameron
2011-10-24 15:39         ` Guenter Roeck
2011-10-24 15:58           ` Jonathan Cameron
2011-10-24 16:10             ` Guenter Roeck
2011-10-24 16:15               ` Jonathan Cameron
2011-10-24 19:33             ` Russell King - ARM Linux [this message]
2011-10-20  9:33 ` [PATCH 6/6] stargate2: example of map configuration for iio to hwmon example Jonathan Cameron
  -- strict thread matches above, loose matches on Subject: below --
2011-10-19 14:47 [RFC V2 PATCH 0/6] IIO in kernel interfaces Jonathan Cameron
2011-10-19 14:47 ` [PATCH 5/6] IIO:hwmon interface client driver Jonathan Cameron
2011-10-19 16:38   ` Guenter Roeck
2011-10-19 16:45     ` Jonathan Cameron

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