From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 13 Jun 2005 13:59:06 +0100 (BST) Received: from extgw-uk.mips.com ([IPv6:::ffff:62.254.210.129]:27929 "EHLO bacchus.net.dhis.org") by linux-mips.org with ESMTP id ; Mon, 13 Jun 2005 13:58:50 +0100 Received: from dea.linux-mips.net (localhost.localdomain [127.0.0.1]) by bacchus.net.dhis.org (8.13.1/8.13.1) with ESMTP id j5DCuBD9024666; Mon, 13 Jun 2005 13:56:11 +0100 Received: (from ralf@localhost) by dea.linux-mips.net (8.13.1/8.13.1/Submit) id j5DCuA15024665; Mon, 13 Jun 2005 13:56:10 +0100 Date: Mon, 13 Jun 2005 13:56:10 +0100 From: Ralf Baechle To: Dominic Sweetman Cc: qemu-devel@nongnu.org, linux-mips@linux-mips.org, Jocelyn Mayer , Fabrice Bellard Subject: Re: Qemu for MIPS Message-ID: <20050613125610.GB4890@linux-mips.org> References: <20050613105944.GA19704@linux-mips.org> <17069.29065.124810.728626@gargle.gargle.HOWL> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17069.29065.124810.728626@gargle.gargle.HOWL> User-Agent: Mutt/1.4.1i 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: 8075 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 Mon, Jun 13, 2005 at 12:44:09PM +0100, Dominic Sweetman wrote: > > Known bugs: > > > > o ll/sc don't use a ll_bit like the real hardware thus right now any atomic > > functions aren't really atomic. > > I suppose you know that the CPUs all implement "break link on > exception" by zeroing the link bit on an 'eret'? That doesn't sound > too hard... It's not hard to add the llbit indeed - maybe I'm trying to hard to be obscure use compatible. Generally Qemu is trading the highest accuracy of emulation for speed ... > Arguably, an emulator should not provide the LLaddr register at all. > It's optional and "only available for debug" - and probably such > debugging is possible another way in an emulator. Robust software > shouldn't depend on assuming the contents make sense. The only use I've seen for this register is having it being used as a cp0 scratch register allowing to save the entire 31 GPRs. Very old Linux/MIPS used to do that but it doesn't match the reality of MIPS ABIs, so I gave up on that very soon. Like 11 years agp :) > Not quite there yet... but well done, again. Ralf