From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59766) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eK5UX-0002tT-Jr for qemu-devel@nongnu.org; Wed, 29 Nov 2017 11:45:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eK5UU-00066Z-Gh for qemu-devel@nongnu.org; Wed, 29 Nov 2017 11:45:45 -0500 Received: from indium.canonical.com ([91.189.90.7]:56610) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eK5UU-00066D-6j for qemu-devel@nongnu.org; Wed, 29 Nov 2017 11:45:42 -0500 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1eK5US-0006JP-9v for ; Wed, 29 Nov 2017 16:45:40 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 418FC2E80C7 for ; Wed, 29 Nov 2017 16:45:40 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 29 Nov 2017 16:33:31 -0000 From: Arno Wagner <645662@bugs.launchpad.net> Reply-To: Bug 645662 <645662@bugs.launchpad.net> Sender: bounces@canonical.com References: <20100923002702.20683.97345.malonedeb@soybean.canonical.com> Message-Id: <151197321182.11140.3495959022669433136.malone@soybean.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 645662] Re: QEMU x87 emulation of trig and other complex ops is only at 64-bit precision, not 80-bit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org That explains it. For most operations that approach works well as basically nobody uses the 80 bit formats directly anyways. Unfortunately asinh() is very badly conditioned in the region tested and it is not enough. A possible approach to fix this would be to use long double (128 bit) were available instead of just double and to document this limitation for double. -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/645662 Title: QEMU x87 emulation of trig and other complex ops is only at 64-bit precision, not 80-bit Status in QEMU: Confirmed Bug description: When doing the regression tests for Python 3.1.2 with Qemu 0.12.5, (Linux= version 2.6.26-2-686 (Debian 2.6.26-25lenny1)), gcc (Debian 4.3.2-1.1) 4.3.2, Python compiled from sources within qemu, 3 math tests fail, apparently because the floating point unit is buggy. Q= meu was compiled from original sources on Debian Lenny with kernel 2.6.34.6 from kernel.org, gcc (Debian 4.3.2= -1.1) 4.3. = Regression testing errors: test_cmath test test_cmath failed -- Traceback (most recent call last): File "/root/tools/python3/Python-3.1.2/Lib/test/test_cmath.py", line 36= 4, in self.fail(error_message) AssertionError: acos0034: acos(complex(-1.0000000000000002, 0.0)) Expected: complex(3.141592653589793, -2.1073424255447014e-08) Received: complex(3.141592653589793, -2.1073424338879928e-08) Received value insufficiently close to expected value. = test_float test test_float failed -- Traceback (most recent call last): File "/root/tools/python3/Python-3.1.2/Lib/test/test_float.py", line 47= 9, in self.assertEqual(s, repr(float(s))) AssertionError: '8.72293771110361e+25' !=3D '8.722937711103609e+25' = test_math test test_math failed -- multiple errors occurred; run in verbose mode fo= r deta =3D> runtests.sh -v test_math le01:~/tools/python3/Python-3.1.2# ./runtests.sh -v test_math test_math BAD 1 BAD 0 GOOD 0 SKIPPED 1 total le01:~/tools/python3/Python-3.1.2# To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/645662/+subscriptions