From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by sourceware.org (Postfix) with ESMTPS id 526043858C66 for ; Mon, 4 Mar 2024 23:24:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 526043858C66 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 526043858C66 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=2604:1380:4641:c500::1 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1709594642; cv=none; b=HQlI0tKuX/RCSAXKWtufI0uQ5docAf4XR/QfyTD5eBUOpw04p03Q79M2nF2QwXJOhREOxy2yKAoFJpevF7VkO/iJzxe+VkQbw9sRSq4vBpUiVL5KXaKrIHkZAhPZaQoCjAo99bTx2DwUcjWe4iaOOfPWvEDlq6FDzDvKA13BZtg= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1709594642; c=relaxed/simple; bh=Fmyz5nWjG0202XV8N2BXs0bEUyo4STNxD6VSUgkILio=; h=DKIM-Signature:Date:From:To:Subject:Message-ID:MIME-Version; b=ZzPMLXd1QY0vmYinJ3EtQzdjqvw87YotZvOM0iRKirkLZRFqEhZZIGp4HYHBoLGpSPZ7Esi/rq9KgTre+hv2j6qqbSGLlnTU0kgQTPgIa/K0XmncFyNJqXnU26AcHzbd4vjBU24dHxTNhAoFVexXzQ42j1A0+dzL4GmgFiRnYyQ= ARC-Authentication-Results: i=1; server2.sourceware.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id C4C6E60C70; Mon, 4 Mar 2024 23:23:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68C88C433C7; Mon, 4 Mar 2024 23:23:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709594639; bh=Fmyz5nWjG0202XV8N2BXs0bEUyo4STNxD6VSUgkILio=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hEd18Fazgb2nCXCWlNUB2lUv1F93opbOaMzzIteLkkZqTb/2gfLD5o9kzEGiay/dH MKJIKJcNwZM9RYtyYVO+zEwzP3N5AuhwU2vgABDoyCRBo9GuhaDvkJ0mrCpmvECwHt wghtlgXlYym1oPBXjVNt+xaJR9Yq3TA4Y+A3AxEAihpjJ7yVl1aLkzVtsevKeyPfe9 W3vUVsEe1QyxUINWJpM6hcEYoUuIT9DDK//9dRHBEbF5PyCjmPgPtd2igYxbiAEH4T cpl50vPrmHyxQXYNW221hHmbnVq4396l2ym2P5TfFRqnDs56WUDg+4rbBXlD8Mkxq3 PsR4n1CtmPUww== Date: Tue, 5 Mar 2024 00:23:55 +0100 From: Alejandro Colomar To: Morten Welinder Cc: linux-man@vger.kernel.org, libc-help@sourceware.org, Adhemerval Zanella Netto Subject: Re: logb() vs floor(log2()) (was: Man page issues: logb, significand, cbrt, log2, log10, exp10) Message-ID: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="K/U1y6t77QUWsxsX" 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 List-Id: --K/U1y6t77QUWsxsX Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Tue, 5 Mar 2024 00:23:55 +0100 From: Alejandro Colomar To: Morten Welinder Cc: linux-man@vger.kernel.org, libc-help@sourceware.org, Adhemerval Zanella Netto Subject: Re: logb() vs floor(log2()) (was: Man page issues: logb, significand, cbrt, log2, log10, exp10) Hi Morten, On Mon, Mar 04, 2024 at 06:52:10PM +0100, Alejandro Colomar wrote: > > logb: > > The formula "floor(log2(x))" should be "floor(log2(fabs(x)))". (Or > > ...abs(...) if it's meant to be math and not C.) I've applied thge following patch: commit 1d83ce827aac984a26430b4f6107182f4b076874 (HEAD -> contrib, alx/contr= ib) Author: Alejandro Colomar Date: Tue Mar 5 00:20:09 2024 +0100 logb.3: logb(x) is floor(log2(fabs(x))) =20 log2(3) doesn't accept negative input, but it seems logb(3) does accept it. =20 Link: Reported-by: Morten Welinder Cc: Adhemerval Zanella Netto Signed-off-by: Alejandro Colomar diff --git a/man3/logb.3 b/man3/logb.3 index 7cbb2470a..7a1ad2f4a 100644 --- a/man3/logb.3 +++ b/man3/logb.3 @@ -58,7 +58,7 @@ .SH DESCRIPTION is 2, .BI logb( x ) is equal to -.BI floor(log2( x ))\fR, +.BI floor(log2(fabs( x )))\f[R],\f[] except that it is probably faster. .P If I'll push it tomorrow. Have a lovely night! Alex --=20 Looking for a remote C programming job at the moment. --K/U1y6t77QUWsxsX Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmXmWAsACgkQnowa+77/ 2zLKVA//cq1s5qhtAad6kTqErwAzlHSvW2KVE72t7mC1S9Ej167RiuVlq8x7Q6h7 HmxlsrgKxihz3oANrUPRvBNMlRnhACppmch/cY2zzp9feSxQEG4vRrRGgEdG97Vq rC1vT2UhAxkJ6AzwW2IN6KWLecQY0FrHF2xuxg6CBmzZCY34w9OZ8SXx9IPos13l fHPeO4z0V8kb4femgaYjT8pbISxJVwcoobO9WCYHMjPqBo5raTWhc1+EbKcihq+h XlX30045A8uFndW5PK3n+HAAo3yB+189VQ6zLiBKKvplw8XzidjAd4ZckCtHzbW8 od5NckdtNioSsVynlkwJD//Z6p4Q/I6zy0dVpXGuzHhx3MZwhgGtxxRVe4jmVp4h I97a4RSwnaVIyxAHIZROGr6GRYAyGpNDZKq1Os2skKGguDs3jw/0KGTFctc2wMU9 sAek0rrEAKbgeu3pv+Xne5q/XuVqKupulDieGzt+YRWzUYW5oRVfeTN1G79TtIts zDbE28qh9EkYMDGIK85fh2QIXVbVD9c69lYqupjtDMoMJKQXdXMPC7y4ty979DUq vQVF5xzAbTQp68pj9HweJoG9bt7+dzml1eflnCtV+elfmL40EcTQyvXWXhHmyLhY piCxinEhcoX4EC8bcbmR6xPUkxBpmqa83rnXItoTSHYEtz+vM48= =9g8r -----END PGP SIGNATURE----- --K/U1y6t77QUWsxsX--