From patchwork Sun Mar 31 20:38:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alejandro Colomar X-Patchwork-Id: 1918354 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=bzntrMyB; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4V75bM1ZzHz1yYH for ; Mon, 1 Apr 2024 07:39:11 +1100 (AEDT) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 82E9A3858C41 for ; Sun, 31 Mar 2024 20:39:08 +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 [IPv6:2604:1380:40e1:4800::1]) by sourceware.org (Postfix) with ESMTPS id 1C3F93858D35 for ; Sun, 31 Mar 2024 20:38:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 1C3F93858D35 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 1C3F93858D35 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2604:1380:40e1:4800::1 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711917529; cv=none; b=w6Ytc2Hya9wOjJocqXPUpHAl9QKcC1w18V1tTSin6JPpyHWbcJpsgw4BFUEZjxABmdfLETe728yNvbVAR5YMCj7jHNVTlGNX4XkkAMaSXz6OMykjdHd+hFcFzy3f4zmStW1ajzW0wNb2TT2ue/X2xi0BJYQ8uP2mOxWc/6fKlQA= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1711917529; c=relaxed/simple; bh=Cs9LzN2DY2mWV7tZ8UOTDErMrCBGrjy0opwrFl9fEKQ=; h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version; b=E2QXW1Erpmt2AYFsScYeqR/2k/TD9OV8j/e/1V40/KjAGuXeIaMoG/h+0H0C8vDL1+j+bFh+F0g9l4LsBJn5cKzVReOuvsQEvUtZTLFA7gccZWVOqWKG7rk+/p7RL7gNvB9TXyvtipfk6APVYYWvvA1XPYy/rBcVs9kD0QqU30o= 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 E35FECE0B4B; Sun, 31 Mar 2024 20:38:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C65EC433F1; Sun, 31 Mar 2024 20:38:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711917523; bh=Cs9LzN2DY2mWV7tZ8UOTDErMrCBGrjy0opwrFl9fEKQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bzntrMyBaCClP+A/CjiaYafKPz5Vx0UNgJ4jXroArTSqA1TgZ0thcJZnaOiG2Xppk /GongSOE00pIm015nGajhX45mZvTfiCJ/X2Nr+aXbyc6ScaHsUzc+iLpSMnf9AW9FJ 4iRpDRW9kDI0vTLiEVO4AJ5Z6+uqYib7X+lo3PytfyTEnWLfcN2zLiCbFKRX9Ketxl xI9RrUYIH3GDxkLnu4XLVkTXuHGC9daBs28qaFYc0b3XfwBPQKDWci4SIqyRExUwMg sVlMSpAaucXwMNe0jZZmX0m0fmAAwV7g/DvcRnhP1U/TZ9Juxm0MNQjcNwkkpXZcYy K7GCIwEHdNQXA== Date: Sun, 31 Mar 2024 22:38:39 +0200 From: Alejandro Colomar To: libc-alpha@sourceware.org Cc: Alejandro Colomar , Morten Welinder , Adhemerval Zanella Netto , Vincent Lefevre , DJ Delorie , Paul Zimmermann , Andreas Schwab Subject: [PATCH v3 1/4] manual: logb(x) is floor(log2(fabs(x))) Message-ID: <20240331203829.23591-2-alx@kernel.org> X-Mailer: git-send-email 2.43.0 References: <20240305161213.14364-1-alx@kernel.org> <20240331203829.23591-1-alx@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240331203829.23591-1-alx@kernel.org> X-Spam-Status: No, score=-10.0 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 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+incoming=patchwork.ozlabs.org@sourceware.org log2(3) doesn't accept negative input, but it seems logb(3) does accept it. Link: Reported-by: Morten Welinder Reviewed-by: DJ Delorie Cc: Adhemerval Zanella Netto Cc: Vincent Lefevre Cc: Paul Zimmermann Cc: Andreas Schwab 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..c54eaebb65 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