Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752975Ab0BVR0G (ORCPT ); Mon, 22 Feb 2010 12:26:06 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39382 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752520Ab0BVR0E (ORCPT ); Mon, 22 Feb 2010 12:26:04 -0500 Message-ID: <4B82BD01.3030008@zytor.com> Date: Mon, 22 Feb 2010 09:21:05 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 MIME-Version: 1.0 To: Borislav Petkov CC: Michal Marek , linux-kbuild , Peter Zijlstra , Andrew Morton , Wu Fengguang , LKML , Jamie Lokier , Roland Dreier , Al Viro , "linux-fsdevel@vger.kernel.org" , Ingo Molnar , Brian Gerst Subject: Re: [PATCH] x86: Add optimized popcnt variants References: <4B75A66A.70005@zytor.com> <4B7BF5D6.3030701@suse.cz> <20100217172040.GC13429@aftab> <4B7C27D8.9050408@suse.cz> <4B7C29C1.10906@suse.cz> <20100218061923.GA1594@liondog.tnic> <20100219142205.GA32533@aftab> <4B7EB6EF.9010405@zytor.com> <20100219164512.GA492@aftab> <4B7EC20C.30607@zytor.com> <20100222141737.GB21233@aftab> In-Reply-To: <20100222141737.GB21233@aftab> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1143 Lines: 36 On 02/22/2010 06:17 AM, Borislav Petkov wrote: > > +config ARCH_HWEIGHT_CFLAGS > + string > + default "-fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64 > + [...] > + > +#ifdef CONFIG_64BIT > +/* popcnt %rdi, %rax */ > +#define POPCNT ".byte 0xf3\n\t.byte 0x48\n\t.byte 0x0f\n\t.byte 0xb8\n\t.byte 0xc7" > +#define REG_IN "D" > +#define REG_OUT "a" > +#else Just a note: this still means rdi is clobbered on x86-64, which is probably fine, but needs to be recorded as such. Since gcc doesn't support clobbers for registers used as operands (sigh), you have to create a dummy output and assign it a "=D" constraint. I don't know if gcc would handle -fcall-saved-rdi here... and if so, how reliably. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/