From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 05 May 2010 11:12:44 +0200 (CEST) Received: from h5.dl5rb.org.uk ([81.2.74.5]:34112 "EHLO h5.dl5rb.org.uk" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1491862Ab0EEJMU (ORCPT ); Wed, 5 May 2010 11:12:20 +0200 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.3/8.14.3) with ESMTP id o459CFf9019261; Wed, 5 May 2010 10:12:16 +0100 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.3/8.14.3/Submit) id o459C04d019250; Wed, 5 May 2010 10:12:00 +0100 Date: Wed, 5 May 2010 10:11:59 +0100 From: Ralf Baechle To: "Kevin D. Kissell" Cc: Shane McDonald , linux-mips@linux-mips.org, Atsushi Nemoto Subject: Re: [MIPS] FPU emulator: allow Cause bits of FCSR to be writeable by ctc1 Message-ID: <20100505091159.GA4016@linux-mips.org> References: <4BE122D1.3000609@paralogos.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4BE122D1.3000609@paralogos.com> User-Agent: Mutt/1.5.20 (2009-08-17) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 26592 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Wed, May 05, 2010 at 12:48:33AM -0700, Kevin D. Kissell wrote: > I'm glad to hear that the patch is functional. It was pretty clear that > it would solve your problem, but I was concerned that the inability to > write the Cause bits was done as a way around some other problem. > Someone went to a certain amount of trouble to not accept them as > inputs, in violation of spec. I just looked back, and the bug was > introduced as part of a patch of Ralf's from April 2005 entitled "Fix > Preemption and SMP problems in the FP emulator". It's unlikely that > overriding CTC semantics actually fixed any underlying problems, but it > may have masked symptoms of problems that we can only hope have been > fixed in the mean time. Anyone run this patch on an FPUless SMP? Oh, > for a 34Kf with a bunch of TCs! ;o) That's commit ID 72402ec9efdb2ea7e0ec6223cf20e7301a57da02 and the patch was comitted during the CVS days which only records the comitter but not the author. The actual author is Atsushi Nemoto. Ralf