Re: [PATCH 1/2] Staging:iio:Prefer using BIT macro

From	Andy Shevchenko <andy.shevchenko@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] Staging:iio:Prefer using BIT macro
Date	2016-02-08 16:20 +0100
Message-ID	<qZVLA-74r-29@gated-at.bofh.it> (permalink)
References	<qZNXI-1zU-3@gated-at.bofh.it> <qZNXI-1zU-1@gated-at.bofh.it> <qZQ9c-3eh-19@gated-at.bofh.it>
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On Mon, Feb 8, 2016 at 11:14 AM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 02/08/2016 07:48 AM, Bhumika Goyal wrote:

>>               value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
>>               data &= AD7816_TEMP_FLOAT_MASK;
>>               if (value < 0)
>> -                     data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
>> +                     data = BIT(AD7816_TEMP_FLOAT_OFFSET) - data;
>
>
> But in this case this is a false positive. The intended semantic meaning
> here is 2**... not BIT(...). Using BIT() here in my opinion only causes
> confusion.

+1. Here clearly the intention is to change sign of the value which
fits less than 32/16/8 bits. 1 << OFFSET represents '-0'.

-- 
With Best Regards,
Andy Shevchenko

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[PATCH 1/2] Staging:iio:Prefer using BIT macro Bhumika Goyal <bhumirks@gmail.com> - 2016-02-08 08:00 +0100
  Re: [PATCH 1/2] Staging:iio:Prefer using BIT macro Lars-Peter Clausen <lars@metafoo.de> - 2016-02-08 10:20 +0100
    Re: [PATCH 1/2] Staging:iio:Prefer using BIT macro Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-08 16:20 +0100

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