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Re: [PATCH 11/31] Add x86-specific parity functions

From One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Newsgroups linux.kernel
Subject Re: [PATCH 11/31] Add x86-specific parity functions
Date 2016-03-29 14:20 +0200
Message-ID <ri0MO-65P-5@gated-at.bofh.it> (permalink)
References <rg3ON-4FE-7@gated-at.bofh.it> <rhcGl-4kX-1@gated-at.bofh.it>
Organization Intel Corporation

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On Sun, 27 Mar 2016 14:45:50 +0800
"zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> wrote:

> From: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
> 
> Signed-off-by: Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com>
> ---
>  arch/x86/include/asm/bitops.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
> index 7766d1c..d3210c0 100644
> --- a/arch/x86/include/asm/bitops.h
> +++ b/arch/x86/include/asm/bitops.h
> @@ -501,6 +501,18 @@ static __always_inline int fls64(__u64 x)
>  
>  #include <asm-generic/bitops/const_hweight.h>
>  
> +#define __arch_parity32(x) (__arch_hweight32(x) & 1)
> +#define __arch_parity4(x)  (__arch_parity32((x) & 0xf))
> +#define __arch_parity8(x)  (__arch_parity32((x) & 0xff))
> +#define __arch_parity16(x) (__arch_parity32((x) & 0xffff))
> +#ifdef CONFIG_X86_32
> +#define __arch_parity64(x) (__arch_parity32((unsigned int)((x) >> 32) ^ (unsigned int)(x)))
> +#else
> +#define __arch_parity64(x) (__arch_hweight64(x) & 1)
> +#endif

arch_hweight32() is a subroutine call to a helper on x86 and the rest
appears to make no sense for this CPU. Gcc has its own parity helper and
even if you are not using that the CPU itself has a parity flag for doing
8bit parity so you just use TEST/J[N]P for parity 8 (and the obvious for 4
and 16). For 32bit parity there is __builtin_parity(). For 64bit
__builtin_parityll().

Alan

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Thread

[PATCH 01/31] bitops: add parity functions Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com> - 2016-03-24 04:10 +0100
  Re: [PATCH 01/31] bitops: add parity functions Denys Vlasenko <dvlasenk@redhat.com> - 2016-03-24 09:40 +0100
    Re: [PATCH 01/31] bitops: add parity functions Andrew Morton <akpm@linux-foundation.org> - 2016-03-24 23:30 +0100
      Re: [PATCH 01/31] bitops: add parity functions Martin Kepplinger <martink@posteo.de> - 2016-03-26 23:10 +0100
        Re: [PATCH 01/31] bitops: add parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 10:00 +0200
    Re: [PATCH 01/31] bitops: add parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 05:40 +0200
      Re: [PATCH 01/31] bitops: add parity functions Sam Ravnborg <sam@ravnborg.org> - 2016-03-27 14:50 +0200
        Re: [PATCH 01/31] bitops: add parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 15:40 +0200
          Re: [PATCH 01/31] bitops: add parity functions Sam Ravnborg <sam@ravnborg.org> - 2016-03-27 20:00 +0200
            Re: [PATCH 01/31] bitops: add parity functions Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com> - 2016-03-28 04:50 +0200
          Re: [PATCH 01/31] bitops: add parity functions Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com> - 2016-03-28 04:20 +0200
      Re: [PATCH 01/31] bitops: add parity functions Sam Ravnborg <sam@ravnborg.org> - 2016-03-28 09:00 +0200
        Re: [PATCH 01/31] bitops: add parity functions Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com> - 2016-03-29 04:30 +0200
          Re: [PATCH 01/31] bitops: add parity functions Joe Perches <joe@perches.com> - 2016-03-29 05:00 +0200
  [PATCH 02/31] Include generic parity.h in some architectures'  bitops.h "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 06:10 +0200
  [PATCH 03/31] Add alpha-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 07:50 +0200
    Re: [PATCH 03/31] Add alpha-specific parity functions Richard Henderson <rth@twiddle.net> - 2016-03-28 20:40 +0200
  [PATCH 04/31] Add avr32-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 07:50 +0200
    Re: [PATCH 04/31] Add avr32-specific parity functions Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> - 2016-03-28 22:10 +0200
  [PATCH 05/31] Add blackfin-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:00 +0200
  [PATCH 07/31] Add mips-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:10 +0200
    Re: [PATCH 07/31] Add mips-specific parity functions David Daney <ddaney.cavm@gmail.com> - 2016-03-28 19:30 +0200
      Re: [PATCH 07/31] Add mips-specific parity functions Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com> - 2016-03-29 04:20 +0200
  [PATCH 06/31] Add ia64-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:10 +0200
  [PATCH 08/31] Add tile-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:20 +0200
  [PATCH 09/31] Add powerpc-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:40 +0200
  [PATCH 11/31] Add x86-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:50 +0200
    Re: [PATCH 11/31] Add x86-specific parity functions One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-03-29 14:20 +0200
  [PATCH 10/31] Add sparc-specific parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 08:50 +0200
    Re: [PATCH 10/31] Add sparc-specific parity functions David Miller <davem@davemloft.net> - 2016-03-28 04:50 +0200
      Re: [PATCH 10/31] Add sparc-specific parity functions Zeng Zhaoxiu <zhaoxiu.zeng@gmail.com> - 2016-03-28 07:50 +0200
        Re: [PATCH 10/31] Add sparc-specific parity functions David Miller <davem@davemloft.net> - 2016-03-28 17:30 +0200
          Re: [PATCH 10/31] Add sparc-specific parity functions Sam Ravnborg <sam@ravnborg.org> - 2016-03-28 17:40 +0200
            Re: [PATCH 10/31] Add sparc-specific parity functions David Miller <davem@davemloft.net> - 2016-03-28 17:50 +0200
  [PATCH 12/31] sunrpc: auth_gss: use parity8 "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:00 +0200
  [PATCH 13/31] mips: use parity functions in cerr-sb1.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:00 +0200
  [PATCH 15/31] media: use parity8 in vivid-vbi-gen.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:10 +0200
  [PATCH 14/31] lib: bch: use parity32 "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:10 +0200
  [PATCH 17/31] input: joystick: use parity32 in grip_mp.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:20 +0200
  [PATCH 18/31] input: joystick: use parity64 in sidewinder.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:20 +0200
  [PATCH 16/31] media: saa7115: use parity functions "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:20 +0200
  [PATCH 19/31] input: serio: use parity16 in ams_delta_serio.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:20 +0200
  [PATCH 22/31] mtd: use parity functions in inftlcore.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:30 +0200
  [PATCH 21/31] mtd: use parity16 in ssfdc.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:30 +0200
    Re: [PATCH 21/31] mtd: use parity16 in ssfdc.c Brian Norris <computersforpeace@gmail.com> - 2016-04-02 01:50 +0200
  [PATCH 20/31] scsi: use parity32 in isci/phy.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:30 +0200
  [PATCH 26/31] input: serio: use parity8 in pcips2.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:40 +0200
  [PATCH 25/31] ethernet: use parity8 in sun/niu.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:40 +0200
    Re: [PATCH 25/31] ethernet: use parity8 in sun/niu.c Michal Nazarewicz <mina86@mina86.com> - 2016-03-28 16:40 +0200
  [PATCH 24/31] mtd: use parity16 in sm_ftl.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:40 +0200
  [PATCH 23/31] crypto: qat: use parity functions in qat_hal.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:40 +0200
  [PATCH 28/31] iio: gyro: use parity32 in adxrs450.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:50 +0200
    Re: [PATCH 28/31] iio: gyro: use parity32 in adxrs450.c Jonathan Cameron <jic23@kernel.org> - 2016-03-28 10:40 +0200
      Re: [PATCH 28/31] iio: gyro: use parity32 in adxrs450.c Lars-Peter Clausen <lars@metafoo.de> - 2016-03-28 11:30 +0200
  [PATCH 29/31] serial: use parity32 in max3100.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:50 +0200
  [PATCH 30/31] input: mouse: use parity8 in elantech "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:50 +0200
  [PATCH 27/31] input: serio: use parity8 in sa1111ps2.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 09:50 +0200
  [PATCH 31/31] ethernet: broadcom: use parity8 in tg3.c "zhaoxiu.zeng" <zhaoxiu.zeng@gmail.com> - 2016-03-27 10:00 +0200

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