From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Gv9Y9-0007n7-Gn for qemu-devel@nongnu.org; Fri, 15 Dec 2006 04:40:17 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Gv9Y8-0007ln-1w for qemu-devel@nongnu.org; Fri, 15 Dec 2006 04:40:16 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Gv9Y7-0007lX-Tt for qemu-devel@nongnu.org; Fri, 15 Dec 2006 04:40:15 -0500 Received: from [62.212.120.90] (helo=fbxmetz.linbox.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1Gv9Y7-0006t6-LL for qemu-devel@nongnu.org; Fri, 15 Dec 2006 04:40:16 -0500 Received: from [192.168.0.14] (helo=[192.168.0.14]) by fbxmetz.linbox.com with esmtp (Exim 3.36 #1 (Debian)) id 1Gv9Y4-0000A1-00 for ; Fri, 15 Dec 2006 10:40:12 +0100 Message-ID: <45826D7B.7000805@linbox.com> From: Ludovic Drolez MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] QEMU x86_64: problems with floats Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Fri, 15 Dec 2006 09:40:17 -0000 To: qemu-devel@nongnu.org Hi ! I've found a bug in Qemu FPU emulation: conversion of floats to strings fails in some cases. For example, Ganglia (cluster monitoring software), shows random values. If I add debug in gmond, I get this: VALUE =2.G= =2.343750= VALUE =2.G= =2.343750= VALUE =9Ö= =93.487236= VALUE =0.6o= =0.640000= VALUE =0.1;= =0.119600= VALUE =0.00= =0.000311= VALUE =0.0= =0.000000= VALUE =0.0= =0.000000= VALUE =9.ê= =95.312500= VALUE =0.9= =0.940000= VALUE =0.4Y= =0.420000= VALUE =0.1;= =0.113054= VALUE =0.00= =0.000536= On the left the float is converted with apr_sprintf, and on the right with printf. Also, floating point operations in PHP also fail... I tested with Qemu 0.8.2 and today's CVS. Of course, it works with a real system (the disk image was then installed on a PE1950). Any ideas ? -- Ludovic DROLEZ Linbox / Free&ALter Soft www.linbox.com www.linbox.org tel: +33 3 87 50 87 90 152 rue de Grigy - Technopole Metz 2000 57070 METZ