Re: [PATCH V3] blackfin: optimize ffz, ffs, ffs, fls, and fls functions

From	Zhaoxiu Zeng <zengzhaoxiu@163.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH V3] blackfin: optimize ffz, __ffs, ffs, __fls, and fls functions
Date	2016-04-15 18:20 +0200
Message-ID	<roeDo-5Pa-23@gated-at.bofh.it> (permalink)
References	<ro6Pw-81V-13@gated-at.bofh.it> <rodQZ-57f-9@gated-at.bofh.it> <roetI-5Ly-37@gated-at.bofh.it>
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在 2016/4/16 0:08, Joe Perches 写道:
> On Fri, 2016-04-15 at 23:20 +0800, zengzhaoxiu@163.com wrote:
>> From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
>>
>> blackfin has popcount instruction (ONES), we can do the efficient
>> computing (ffz, __ffs, ffs, __fls, and fls) use this instruction.
> []
>> diff --git a/arch/blackfin/include/asm/bitops.h b/arch/blackfin/include/asm/bitops.h
> []
>> +static inline unsigned int __arch_hweight64(__u64 w)
>> +{
>> +	return __arch_hweight32((unsigned int)(w >> 32)) +
>> +	       __arch_hweight32((unsigned int)w);
>> +}
> trivia:  perhaps this is more readable as:
>
> 	return __arch_hweight32(upper_32_bits(w)) +
> 	       __arch_hweight32(lower_32_bits(w));
>
>

Yes.
I just moved these codes from the bottom of  bitops.h, didn't change anything.

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[PATCH] blackfin: optimize ffz, __ffs, ffs, __fls, and fls functions zengzhaoxiu@163.com - 2016-04-15 10:00 +0200
  [PATCH V2] blackfin: optimize ffz, __ffs, ffs, __fls, and fls functions zengzhaoxiu@163.com - 2016-04-15 10:30 +0200
  Re: [PATCH] blackfin: optimize ffz, __ffs, ffs, __fls, and fls  functions kbuild test robot <lkp@intel.com> - 2016-04-15 11:20 +0200
  [PATCH V3] blackfin: optimize ffz, __ffs, ffs, __fls, and fls functions zengzhaoxiu@163.com - 2016-04-15 17:30 +0200
    Re: [PATCH V3] blackfin: optimize ffz, __ffs, ffs, __fls, and fls  functions Joe Perches <joe@perches.com> - 2016-04-15 18:10 +0200
      Re: [PATCH V3] blackfin: optimize ffz, __ffs, ffs, __fls, and fls  functions Zhaoxiu Zeng <zengzhaoxiu@163.com> - 2016-04-15 18:20 +0200

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