From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1DwmDB-0003Um-7a for qemu-devel@nongnu.org; Sun, 24 Jul 2005 15:32:33 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1DwmD7-0003SK-44 for qemu-devel@nongnu.org; Sun, 24 Jul 2005 15:32:30 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1DwmD6-0003Q7-DR for qemu-devel@nongnu.org; Sun, 24 Jul 2005 15:32:28 -0400 Received: from [84.96.92.61] (helo=sMtp.neuf.fr) by monty-python.gnu.org with esmtp (Exim 4.34) id 1DwmEi-0006A1-UG for qemu-devel@nongnu.org; Sun, 24 Jul 2005 15:34:09 -0400 Received: from [84.99.204.19] by sp604002mt.gpm.neuf.ld (Sun Java System Messaging Server 6.2-2.05 (built Apr 28 2005)) with ESMTP id <0IK500EB6CJ1KFE0@sp604002mt.gpm.neuf.ld> for qemu-devel@nongnu.org; Sun, 24 Jul 2005 21:23:25 +0200 (CEST) Date: Sun, 24 Jul 2005 21:23:54 +0200 From: Fabrice Bellard Subject: Re: [Qemu-devel] Targetting a specific processor type In-reply-to: <79bf9848050724115119319857@mail.gmail.com> Message-id: <42E3EACA.5070803@bellard.org> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii; format=flowed Content-transfer-encoding: 7BIT References: <79bf9848050724115119319857@mail.gmail.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mike Swanson , qemu-devel@nongnu.org Mike Swanson wrote: > I have a need currently to emulate specifically an 80486 processor, > nothing lower or higher than that. > > Is it possible to configure QEMU in any way to simply emulate a 486, > or compile it like that? It is currently not possible, but adding it would be possible: the first step is to modify the cpu init in target-i386/helper2.c to disable most of the cpuid bits. The second step is to modify target-i386/translate.c to test every cpuid bit (it is not done for all instructions: I did it mostly for MMX/SSE). Fabrice.