From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 2/5] bitops: compile time optimization for
 hweight_long(CONSTANT)
Date: Wed, 03 Feb 2010 19:47:55 +0100
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Cc: Andrew Morton <akpm@linux-foundation.org>,
	Wu Fengguang <fengguang.wu@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Jamie Lokier <jamie@shareable.org>,
	Roland Dreier <rdreier@cisco.com>,
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	Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@amd64.org>
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On Wed, 2010-02-03 at 19:14 +0100, Borislav Petkov wrote:

> alternative("call hweightXX", "popcnt", X86_FEATURE_POPCNT)

Make sure to apply a 0xff bitmask to the popcnt r16 call for hweight8(),
and hweight64() needs a bit of magic for 32bit, but yes, something like
that ought to work nicely.