From patchwork Mon Mar 4 22:40:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alejandro Colomar X-Patchwork-Id: 86773 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 16F873858431 for ; Mon, 4 Mar 2024 22:41:29 +0000 (GMT) X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by sourceware.org (Postfix) with ESMTPS id 9FFFF3858C55 for ; Mon, 4 Mar 2024 22:41:06 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9FFFF3858C55 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=kernel.org ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 9FFFF3858C55 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=145.40.73.55 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1709592069; cv=none; b=veFTGnHlpZNrr0MtfnSJdhXpUASEP+aQDmyjSKzRZ3rnbVGEd5eevM5ui7bU1ykOjqGOlNHiHtaHhYpcM7nJ1jeazULOHZ8Ololp8mCwCRN5c9fR4ehvkSo2i/KHfsZOOfVx7sHs79VRhNkh92ig0oACrSPWbK7eCfzQ9cG51fw= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1709592069; c=relaxed/simple; bh=Z67hIalOtzpKbRVh8uKkhxqReOALSzqHX1v0ig7q5q8=; h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version; b=n9hZO6ki/DUl8GoPRCCztEsWk1v5/wU2vNtq6PQKtrDD92WpBZClwqbWd7P1VelsR3oHbUh339B9GGqjNn/SBPGiqtkpJUkPVUcC5HswC2RZLXu6WE17Z1sY+nKHb36VB1mT5PuakSRJJdTGer+mF1ID/IuitL1/3MpTgoj47Sc= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 87DDFCE17D5; Mon, 4 Mar 2024 22:41:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BAAABC433F1; Mon, 4 Mar 2024 22:41:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709592062; bh=Z67hIalOtzpKbRVh8uKkhxqReOALSzqHX1v0ig7q5q8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aHazRFJo2ximJMbmy+1oG6jvDNbT4SQa0NYQ7zVzJg6LDDarhBpFML4dSTaSqYrII 2gNr0GfQ/yT/WVZY6WhfOmBZetUmVavWGHKAglFktH+mNsZ0uxg1LPaA4UfFAIbGIk Mwctrz5ZIv0Dsm5H7JBCYHBEwJSTPFt25GWQtTcJZq9HX9jan253fQvyNkJ1ZYVrSR klTOHErL4GJOuA8gYTddqtexSIHtEgY5OYt3rLXo8VdrAiGFEia9lnCVZHQaFVl64L q04FJuLvNzNQKPxB5JvqczTiu3O1F/mqDFeyRiTKTmkjuFavAsE9nxq/hfuDU7ZkjX 6ZEnucfqKOVFA== Date: Mon, 4 Mar 2024 23:40:59 +0100 From: Alejandro Colomar To: libc-alpha@sourceware.org Cc: Alejandro Colomar , Morten Welinder , Adhemerval Zanella Netto Subject: [PATCH] manual: logb(x) is floor(log2(fabs(x))) Message-ID: <20240304224051.4862-1-alx@kernel.org> X-Mailer: git-send-email 2.43.0 References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-10.3 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org log2(3) doesn't accept negative input, but it seems logb(3) does accept it. Link: Reported-by: Morten Welinder Cc: Adhemerval Zanella Netto Signed-off-by: Alejandro Colomar --- manual/math.texi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/manual/math.texi b/manual/math.texi index 2f6ee253b9..bf4027c4ee 100644 --- a/manual/math.texi +++ b/manual/math.texi @@ -561,7 +561,7 @@ These functions return the base-2 logarithm of @var{x}. @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} These functions extract the exponent of @var{x} and return it as a floating-point value. If @code{FLT_RADIX} is two, @code{logb} is equal -to @code{floor (log2 (x))}, except it's probably faster. +to @code{floor (log2 (fabs ((x)))}, except it's probably faster. If @var{x} is de-normalized, @code{logb} returns the exponent @var{x} would have if it were normalized. If @var{x} is infinity (positive or