From: "Vaittinen, Matti" <Matti.Vaittinen@fi.rohmeurope.com>
To: David Laight <David.Laight@ACULAB.COM>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matti Vaittinen <mazziesaccount@gmail.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>, Jiri Kosina <trivial@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Yury Norov <yury.norov@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Geert Uytterhoeven <geert+renesas@glider.be>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] bitops: Add single_bit_set()
Date: Tue, 23 Nov 2021 11:42:32 +0000 [thread overview]
Message-ID: <c7b488fd-a0a7-2ec7-c711-7a6507fb2731@fi.rohmeurope.com> (raw)
In-Reply-To: <874db8b91ff04001a8958f100a614ed8@AcuMS.aculab.com>
On 11/23/21 12:42, David Laight wrote:
> From: Vaittinen, Matti
>> Sent: 22 November 2021 13:19
>>
>> On 11/22/21 14:57, Andy Shevchenko wrote:
>>> On Mon, Nov 22, 2021 at 12:42:21PM +0000, Vaittinen, Matti wrote:
>>>> On 11/22/21 13:28, Andy Shevchenko wrote:
>>>>> On Mon, Nov 22, 2021 at 01:03:25PM +0200, Matti Vaittinen wrote:
>>>
>>> What do you mean by this?
>>>
>>> hweight() will return you the number of the non-zero elements in the set.
>>
>> Exactly. The function I added did only check if given set of bits had
>> only one bit set.
>
> Checking for exactly one bit can use the (x & (x - 1)) check on
> non-zero values
Thanks! This was educating. I admit I had to launch a calculator with
bit editor to see where this went to. I doubt I had ever noticed such
possibility if I didn't send the original patch. I guess this is the
true power of the collaboration ;)
Best Regards
--Matti
--
The Linux Kernel guy at ROHM Semiconductors
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND
~~ this year is the year of a signature writers block ~~
next prev parent reply other threads:[~2021-11-23 11:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-22 11:03 [PATCH 0/4] Provide event map helper for regulator drivers Matti Vaittinen
2021-11-22 11:03 ` [PATCH 1/4] bitops: Add single_bit_set() Matti Vaittinen
2021-11-22 11:28 ` Andy Shevchenko
2021-11-22 12:42 ` Vaittinen, Matti
2021-11-22 12:57 ` Andy Shevchenko
2021-11-22 13:00 ` Andy Shevchenko
2021-11-22 13:18 ` Vaittinen, Matti
2021-11-23 10:42 ` David Laight
2021-11-23 10:47 ` Andy Shevchenko
2021-11-23 10:58 ` David Laight
2021-11-23 13:43 ` 'Andy Shevchenko'
2021-11-23 14:36 ` David Laight
2021-11-23 11:42 ` Vaittinen, Matti [this message]
2021-11-22 17:54 ` Yury Norov
2021-11-22 19:56 ` Andy Shevchenko
2021-11-23 7:51 ` Yury Norov
2021-11-23 5:26 ` Vaittinen, Matti
2021-11-23 7:33 ` Yury Norov
2021-11-23 9:03 ` Andy Shevchenko
2021-11-23 9:10 ` Geert Uytterhoeven
2021-11-22 11:03 ` [PATCH 2/4] regulators: Add regulator_err2notif() helper Matti Vaittinen
2021-11-22 11:04 ` [PATCH 3/4] regulators: irq_helper: Provide helper for trivial IRQ notifications Matti Vaittinen
2021-11-22 11:48 ` Andy Shevchenko
2021-11-22 12:44 ` Vaittinen, Matti
2021-11-22 11:04 ` [PATCH 4/4] regulator: Drop unnecessary struct member Matti Vaittinen
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