Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756935Ab0BCSsU (ORCPT ); Wed, 3 Feb 2010 13:48:20 -0500 Received: from casper.infradead.org ([85.118.1.10]:35905 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756024Ab0BCSsS (ORCPT ); Wed, 3 Feb 2010 13:48:18 -0500 Subject: Re: [PATCH 2/5] bitops: compile time optimization for hweight_long(CONSTANT) From: Peter Zijlstra To: Borislav Petkov Cc: Andrew Morton , Wu Fengguang , LKML , Jamie Lokier , Roland Dreier , Al Viro , "linux-fsdevel@vger.kernel.org" , Ingo Molnar , "H. Peter Anvin" In-Reply-To: <20100203181425.GB1367@aftab> References: <20100130094515.475881280@intel.com> <20100130094957.692671259@intel.com> <20100201124825.cc024f2a.akpm@linux-foundation.org> <20100203133951.GA24357@localhost> <20100203070825.e36b3932.akpm@linux-foundation.org> <1265210157.24455.646.camel@laptop> <20100203074251.e2caa3f3.akpm@linux-foundation.org> <20100203181425.GB1367@aftab> Content-Type: text/plain; charset="UTF-8" Date: Wed, 03 Feb 2010 19:47:55 +0100 Message-ID: <1265222875.24455.1020.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 540 Lines: 13 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/