From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 27E80394B02B for ; Wed, 12 Jan 2022 22:17:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 27E80394B02B Received: from mail-qt1-f198.google.com (mail-qt1-f198.google.com [209.85.160.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-647-ViCSfck9NBO40hePccRkpQ-1; Wed, 12 Jan 2022 17:17:45 -0500 X-MC-Unique: ViCSfck9NBO40hePccRkpQ-1 Received: by mail-qt1-f198.google.com with SMTP id y1-20020ac87041000000b002c3db9c25f8so3568211qtm.5 for ; Wed, 12 Jan 2022 14:17:45 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=nxWitO3NQ3VJvH565Xv4RVHgsIs14OKC1INM+OEdNtk=; b=PUa3LoN+dDnLCHVCoLmpWO5vTVlrta1Q1cK7hAcJYkvL621ueMBSGsqJmHxxd5YDNo TmU07Q/PLip1UKnOBupbt01bJTLe4+/Qgqz9HApCxuhbkaDra7xkWdFes08bGlw17JDt Gr/kUYnyBmYBBwWBORNCP6njMD8xWyLFPgAdTf1+5oLQ4+BVFc54LoX8pJmo1deWBSHk 3HYypjc+id/IULK4FNFkKFo8/I8cQrcRaPvc4jozKyTSU/JTQnCf1VPNKO6PH9p3ePct Wx/jlaF6+9kczghm6wdXQs24LcOatgn5Mls9j0BMf4bY7boIRTy93mhRpsjexmjx+mDo WTiA== X-Gm-Message-State: AOAM531uCMJPPMPMvhgbMggQRMJDMH2HgV2sn7+IaZRZwiNsInnvfNmE 3AWPOTAz6uekSC7+rSkj3vjZWRaCvxZo4vC99O8E06ueZp+pmiyyltnTAeZAf74RIdo0LKcesQ2 K+Jko0/wkgyqoMyvmlRy/ X-Received: by 2002:a05:6214:27c3:: with SMTP id ge3mr1556477qvb.118.1642025865175; Wed, 12 Jan 2022 14:17:45 -0800 (PST) X-Google-Smtp-Source: ABdhPJzWwQssHulSid7rYLXkSryOhlp4chRHoSDoJA4jfyKIysDBseHPFsHjD3jDLOkYTT63dOPbQg== X-Received: by 2002:a05:6214:27c3:: with SMTP id ge3mr1556471qvb.118.1642025864979; Wed, 12 Jan 2022 14:17:44 -0800 (PST) Received: from [192.168.0.241] (135-23-175-80.cpe.pppoe.ca. [135.23.175.80]) by smtp.gmail.com with ESMTPSA id f13sm829314qtf.21.2022.01.12.14.17.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 12 Jan 2022 14:17:44 -0800 (PST) Message-ID: Date: Wed, 12 Jan 2022 17:17:43 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: correctly rounded mathematical functions To: Paul Zimmermann , Joseph Myers Cc: libc-alpha@sourceware.org References: From: Carlos O'Donell Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Jan 2022 22:17:48 -0000 On 1/5/22 11:03, Paul Zimmermann wrote: > I see one solution: declare cr_xxx as an alias for xxx for all functions, > and create corresponding bugzilla issues for those which are not (yet) CR. > As new CR functions are integrated within glibc, the corresponding bugs > will be declared as fixed. One could imagine macros like CR_SIN_IS_CR > to tell the user that the cr_sin function is really correctly rounded. This isn't a good idea given the expectations that users will have for calling the cr_* functions. Either they are defined and have the expected semantics or they are not defined. However, this makes the semantics of the ABI a bit difficult, we would probably want the ABI to appear as implementations are made available, and that can be on a per-arch basis. >> * When you have correctly rounded functions for x86 "extended" (ldbl-96 in >> glibc), do those also work properly for the m68k variant of that format >> (which handles biased exponent 0 like other biased exponents, so has >> normal and subnormal exponent ranges going one exponent smaller), or do >> you avoid providing the cr_* functions for that format variant? > > at the moment, unless we get more manpower, we don't plan to provide the > m68k variants. In these cases then we would not define the functions, and they would not be available for use. This poses a porting hazard for the cr_* functions, which is unfortunate, but not the worst. I'm not opposed to per-arch variations in ABI. -- Cheers, Carlos.