From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753377Ab0DOLmk (ORCPT ); Thu, 15 Apr 2010 07:42:40 -0400 Received: from mail2.shareable.org ([80.68.89.115]:51134 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753137Ab0DOLmi (ORCPT ); Thu, 15 Apr 2010 07:42:38 -0400 Date: Thu, 15 Apr 2010 12:41:47 +0100 From: Jamie Lokier To: Avi Kivity Cc: David Howells , Linus Torvalds , Matthew Wilcox , Ralf Baechle , mingo@elte.hu, tglx@linutronix.de, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] X86: Optimise fls(), ffs() and fls64() Message-ID: <20100415114146.GA10863@shareable.org> References: <20100406133026.GD20577@parisc-linux.org> <20100326144241.8583.95617.stgit@warthog.procyon.org.uk> <28287.1269625325@redhat.com> <20100326175827.GD20055@linux-mips.org> <17213.1271245760@redhat.com> <3879.1271321292@redhat.com> <4BC6D334.8050607@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BC6D334.8050607@redhat.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avi Kivity wrote: > Likely. But we haven't tested all current and future x86 clones, and > they may be based off the Intel documentation instead of the AMD > documentation. I wonder about that too. I got the impression Transmeta did lots of testing real x86s in all sorts of corner cases, because the manuals don't cover everything that the broad base of software depends on in practice. Clone makers have to do it to a much higher standard than emulators because you can't generally release patches... I think Via (including whatever the CPU line was formerly called) have been bitten a few times by not quite matching software expectations. Even Intel was caught on x86_64 at the beginning by slight differences when they cloned AMD's design :-) -- Jamie