From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 1/3] X86: Optimise fls(), ffs() and fls64() Date: Fri, 26 Mar 2010 10:45:05 -0700 (PDT) Message-ID: References: <20100326144241.8583.95617.stgit@warthog.procyon.org.uk> <28287.1269625325@redhat.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:53206 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753226Ab0CZRtm (ORCPT ); Fri, 26 Mar 2010 13:49:42 -0400 In-Reply-To: <28287.1269625325@redhat.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: David Howells Cc: mingo@elte.hu, tglx@linutronix.de, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org On Fri, 26 Mar 2010, David Howells wrote: > > Hmmm... My ancient Borland Assembler dead-tree manual doesn't mention that. I went back and checked the old Intel 386 docs from -92 or something, and it was "undefined" in there too. So at least Intel seems to have been very consistent on this. That said, maybe all implementations actually do the "don't touch" thing. But I do have this memory of us doing this ten+ years ago, though, and having to check the ZF after all. Which is why I reacted to the patch in the first place and checked the documentation. Linus