From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 66582 invoked by alias); 5 Oct 2017 12:48:22 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 66409 invoked by uid 89); 5 Oct 2017 12:48:07 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=H*x:version, HTo:U*macro, H*UA:version, central X-HELO: mx0a-001b2d01.pphosted.com Received: from mx0b-001b2d01.pphosted.com (HELO mx0a-001b2d01.pphosted.com) (148.163.158.5) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 05 Oct 2017 12:48:06 +0000 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v95CiPRp002819 for ; Thu, 5 Oct 2017 08:48:04 -0400 Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com [195.75.94.107]) by mx0b-001b2d01.pphosted.com with ESMTP id 2ddmdf2fym-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 05 Oct 2017 08:48:04 -0400 Received: from localhost by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 5 Oct 2017 13:48:00 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v95Clxxf17891548; Thu, 5 Oct 2017 12:47:59 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 242C242041; Thu, 5 Oct 2017 13:43:50 +0100 (BST) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 145124203F; Thu, 5 Oct 2017 13:43:50 +0100 (BST) Received: from oc3748833570.ibm.com (unknown [9.152.213.178]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 5 Oct 2017 13:43:50 +0100 (BST) Received: by oc3748833570.ibm.com (Postfix, from userid 1000) id 473BBD835F0; Thu, 5 Oct 2017 14:47:59 +0200 (CEST) Subject: Re: [RFC][06/19] Target FP: Use print_floating in tdep code To: macro@imgtec.com (Maciej W. Rozycki) Date: Thu, 05 Oct 2017 12:48:00 -0000 From: "Ulrich Weigand" Cc: gdb-patches@sourceware.org In-Reply-To: from "Maciej W. Rozycki" at Oct 04, 2017 11:26:30 PM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 17100512-0040-0000-0000-000003FF9B53 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17100512-0041-0000-0000-000020A1094E Message-Id: <20171005124759.473BBD835F0@oc3748833570.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-10-05_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1710050179 X-SW-Source: 2017-10/txt/msg00101.txt.bz2 Hi Maciej, > Thank you for your effort in getting this area right, the limitations in > our FP arithmetic handling really troubled me. Thanks for testing, this is really helful! > I pushed your changes 01-06 combined through testing with a couple of > MIPS/Linux targets, native and crossed (from x86-64), and all have > consistently regressed in gdb.base/dfp-exprs.exp, e.g.: [...] > i.e. values to be output are missing, numerous across this test case. No > other regressions though. This is surprising. Could you do a quick check whether the regression is introduced with patch 6 of the series, or already with patch 5? > Also I find the new formatting of `info all-registers' output > functionally regressed (rather than merely "changed a bit"), e.g.: [...] > I think we need to get the ability to align output (previously achieved > with formatters, i.e. "%-17.9g" and "%-24.17g") restored; frankly I find > the new format unreadable, which makes me consider it unacceptable. I see, this really doesn't look good. It shouldn't be very difficult to fix, since in part 7 of the series I actually introduce routines to provide *formatted* output as well. So I think I'll prepare an updated patch set that moves patch 6 after patch 7 and uses those formatted print routines in the MIPS back-end. Once I've done that, it would be good if you could re-run your tests to make sure the regression is really fixed. > NB while striving for FP arithmetic to match target hardware accurately > we'll have to handle the two opposite qNaN vs sNaN encodings that the MIPS > architecture now supports, i.e. the original IEEE 754-1985 format with the > quiet bit being 0 and the recent IEEE 754-2008 format with the quiet bit > being 1. This obviously has to be taken into account in calculations, > according to the hardware mode being active (or the relevant ELF file > header flag in the binary chosen to debug if not connected to any target), > and I do hope MPFR can be switched at the run time to do the right thing. > > This can of course be the next step, once we've settled on the base > implementation -- and I'll take care of the MIPS architecture bits. Agreed. Once the new infrastructure is in place, there will be one central place where target-specific FP arithmetic tweaks can be implemented. Bye, Ulrich -- Dr. Ulrich Weigand GNU/Linux compilers and toolchain Ulrich.Weigand@de.ibm.com