From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756750Ab2DXRRh (ORCPT ); Tue, 24 Apr 2012 13:17:37 -0400 Received: from terminus.zytor.com ([198.137.202.10]:35878 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756594Ab2DXRRf (ORCPT ); Tue, 24 Apr 2012 13:17:35 -0400 Message-ID: <4F96E01E.6040109@zytor.com> Date: Tue, 24 Apr 2012 10:17:18 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Linus Torvalds , Andrew Morton , Juri Lelli , Ingo Molnar , Thomas Gleixner Subject: Re: [RFC][PATCH 3/3] math128, x86_64: Implement {mult,add}_u128 in 64bit asm References: <20120424161039.293018424@chello.nl> <20120424162224.588822231@chello.nl> <4F96D604.5050709@zytor.com> <1335285395.28150.204.camel@twins> In-Reply-To: <1335285395.28150.204.camel@twins> X-Enigmail-Version: 1.4.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/24/2012 09:36 AM, Peter Zijlstra wrote: > On Tue, 2012-04-24 at 09:34 -0700, H. Peter Anvin wrote: >> On 04/24/2012 09:10 AM, Peter Zijlstra wrote: >> >> Are you sure that gcc won't simply generate this code already if given >> "unsigned __int128"? > > It might, but I've been told some GCC versions had issues, also lots of > archs fall back to libgcc functions. > Yes, but this is specific to x86-64. If gcc can generate the code it can also schedule the code, which it can't for assembly... -hpa