linux-kernel - Re: [PATCH v2 10/30] Add x86-specific parity functions

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Message-ID: <20160406105315.GB13719@pd.tnic>
Date:	Wed, 6 Apr 2016 12:53:15 +0200
From:	Borislav Petkov <bp@...e.de>
To:	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Cc:	zengzhaoxiu@....com, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, dvlasenk@...hat.com, akpm@...ux-foundation.org,
	dvyukov@...gle.com, keescook@...omium.org,
	linux-kernel@...r.kernel.org, Zhaoxiu Zeng <zhaoxiu.zeng@...il.com>
Subject: Re: [PATCH v2 10/30] Add x86-specific parity functions

On Wed, Apr 06, 2016 at 11:37:37AM +0100, One Thousand Gnomes wrote:
> Even that would still be wrong for the smaller parity values. The CPU
> supports 8bit parity directly going back to the 8086 so the
> implementation for 8bit and I think 16bit is still wrong.

I was objecting to the unnecessary replication of the hweight/popcnt
glue.

And yes, one could look up the definition of the parity flag on x86 and
then base the implementation of all those smaller ones on that as the
hardware does it for one practically for free there.

:-)

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--