From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) by sourceware.org (Postfix) with ESMTPS id 284B53840C2A for ; Mon, 4 Jan 2021 16:25:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 284B53840C2A Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=inria.fr Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=Paul.Zimmermann@inria.fr X-IronPort-AV: E=Sophos;i="5.78,474,1599516000"; d="scan'208";a="485340309" Received: from tomate.loria.fr (HELO tomate) ([152.81.10.51]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jan 2021 17:25:06 +0100 Date: Mon, 04 Jan 2021 17:25:06 +0100 Message-Id: From: Paul Zimmermann To: Wilco Dijkstra Cc: libc-alpha@sourceware.org In-Reply-To: (message from Wilco Dijkstra via Libc-alpha on Mon, 4 Jan 2021 12:15:30 +0000) Subject: Re: [PATCH 1/5] Remove slow paths from asin References: X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: Mon, 04 Jan 2021 16:25:09 -0000 Dear Wilco, I have a few comments on this first patch: - the title only mentions asin, but the patch also deals with acos - it would be nice to explain where the "Max ULP" come from, to allow future developers to debug the code if needed. - it would be nice to have a summary with the maximal ulp error at the top of each function (__ieee754_asin and __ieee754_acos) - for __ieee754_acos the largest claimed error is 0.52 ULP for 0.5 <= |x| < 0.96875, but I find an error of more than 0.522 ulps for x = 0x1.dffff58d80953p-1 (on x86_64). Best regards, Paul