From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1FMZTD-0004Os-LJ
	for qemu-devel@nongnu.org; Thu, 23 Mar 2006 18:43:59 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1FMZTC-0004Ns-6J
	for qemu-devel@nongnu.org; Thu, 23 Mar 2006 18:43:58 -0500
Received: from [199.232.76.173] (helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1FMZTB-0004Nk-TL
	for qemu-devel@nongnu.org; Thu, 23 Mar 2006 18:43:57 -0500
Received: from [66.249.92.206] (helo=uproxy.gmail.com)
	by monty-python.gnu.org with esmtp (Exim 4.52) id 1FMZTs-0002yQ-OQ
	for qemu-devel@nongnu.org; Thu, 23 Mar 2006 18:44:40 -0500
Received: by uproxy.gmail.com with SMTP id s2so200521uge
	for <qemu-devel@nongnu.org>; Thu, 23 Mar 2006 15:43:55 -0800 (PST)
From: Lyonel Vincent <lyonel.vincent@gmail.com>
Message-Id: <20060324004315.dd56f108.lyonel.vincent@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] i386 emulation on PowerPC host
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
Date: Thu, 23 Mar 2006 23:44:00 -0000
To: qemu-devel@nongnu.org

Hi all,

Having noticed very wierd behaviour of some operations under an x86
Qemu guest running on a PowerPC (32 bits), I have compiled the
following test program under Linux/i386:

#include <stdio.h>
#include <math.h>

void main()
{
  float x = exp(1)*exp(1);
  float y = exp(2);

  printf("%f = %f\n", x, y);
}

When run under native i386 Linux, this program displays:
$ ./mathtest
7.389056 = 7.389056

as expected

but with a CVS snapshot (as of 2006-03-23) of Qemu, one gets:
$ ./mathtest
7.389056 = -inf

[that's the same binary running under Linux/i386 inside Qemu on a
PowerPC host]

I also have other strange symptoms like cp sometimes complaining about
memory exhaustion but I haven't been able to reproduce those yet...

Does anybody have an idea of what the problem could be and how I could
help to fix that?

cheers,
Lyonel.