Module Name: src Committed By: martin Date: Thu Mar 6 10:57:01 UTC 2014
Added Files: src/lib/libm/noieee_src: n_log2.c Log Message: log2() for vax To generate a diff of this commit: cvs rdiff -u -r0 -r1.1 src/lib/libm/noieee_src/n_log2.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Added files: Index: src/lib/libm/noieee_src/n_log2.c diff -u /dev/null src/lib/libm/noieee_src/n_log2.c:1.1 --- /dev/null Thu Mar 6 10:57:01 2014 +++ src/lib/libm/noieee_src/n_log2.c Thu Mar 6 10:57:01 2014 @@ -0,0 +1,59 @@ +/* $NetBSD: n_log2.c,v 1.1 2014/03/06 10:57:01 martin Exp $ */ +/*- + * Copyright (c) 2014 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Martin Husemann <mar...@netbsd.org>. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* LOG2(X) + * RETURN THE BASE 10 LOGARITHM OF x + * + * Required kernel function: + * log(x) + * + * Method : + * log(x) + * log2(x) = --------- + * log(2) + */ + +#define _LIBM_STATIC +#include "mathimpl.h" + + +static const double ln2 = .6931471805599453094172321214581765680755; + +double +log2(double x) +{ + return log(x)/ln2; +} + +float +log2f(float x) +{ + return logf(x)/ln2; +}