diff options
| author | joerg <joerg@NetBSD.org> | 2011-08-03 14:13:07 +0000 |
|---|---|---|
| committer | joerg <joerg@NetBSD.org> | 2011-08-03 14:13:07 +0000 |
| commit | f73a9c72a8ea0a66b7bfa17fd400c20a45b6da2c (patch) | |
| tree | 108a805eafcf1919e8378fddf09a46b381c9065b /lib/libm/src | |
| parent | 7c2bed2aa85a8ae35827ce5b121e3df125194305 (diff) | |
Add logbl(3).
Diffstat (limited to 'lib/libm/src')
| -rw-r--r-- | lib/libm/src/s_logb.c | 6 | ||||
| -rw-r--r-- | lib/libm/src/s_logbl.c | 76 |
2 files changed, 81 insertions, 1 deletions
diff --git a/lib/libm/src/s_logb.c b/lib/libm/src/s_logb.c index 9a77e49e6dc..6d89e5428a2 100644 --- a/lib/libm/src/s_logb.c +++ b/lib/libm/src/s_logb.c @@ -12,7 +12,7 @@ #include <sys/cdefs.h> #if defined(LIBM_SCCS) && !defined(lint) -__RCSID("$NetBSD: s_logb.c,v 1.11 2002/05/26 22:01:57 wiz Exp $"); +__RCSID("$NetBSD: s_logb.c,v 1.12 2011/08/03 14:13:07 joerg Exp $"); #endif /* @@ -24,6 +24,10 @@ __RCSID("$NetBSD: s_logb.c,v 1.11 2002/05/26 22:01:57 wiz Exp $"); #include "math.h" #include "math_private.h" +#ifndef __HAVE_LONG_DOUBLE +__strong_alias(logbl,logb) +#endif + double logb(double x) { diff --git a/lib/libm/src/s_logbl.c b/lib/libm/src/s_logbl.c new file mode 100644 index 00000000000..42899905156 --- /dev/null +++ b/lib/libm/src/s_logbl.c @@ -0,0 +1,76 @@ +/* $NetBSD: s_logbl.c,v 1.1 2011/08/03 14:13:07 joerg Exp $ */ + +/*- + * Copyright (c) 2011 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Joerg Sonnenberger. + * + * 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. + */ + +#include <sys/cdefs.h> +__RCSID("$NetBSD: s_logbl.c,v 1.1 2011/08/03 14:13:07 joerg Exp $"); + +#include "namespace.h" + +#include <float.h> +#include <math.h> +#include <machine/ieee.h> + +#ifdef __HAVE_LONG_DOUBLE + +#if LDBL_MANT_DIG == 64 +#define FROM_UNDERFLOW 0x1p65L +#elif LDBL_MANT_DIG == 113 +#define FROM_UNDERFLOW 0x1p114L +#else +#error Unsupported long double format +#endif + +long double +logbl(long double x) +{ + union ieee_ext_u u; + + if (x == 0.0L) + return -1.0L / fabsl(x); /* -HUGE_VALL + exception */ + + u.extu_ld = x; + + if (u.extu_ext.ext_exp == EXT_EXP_INFNAN) + return fabsl(x); /* NaN or +Inf */ + + if (u.extu_ext.ext_exp == 0) { + /* + * Scale denormalized numbers slightly, + * so that they are normal. + */ + u.extu_ld *= FROM_UNDERFLOW; + return u.extu_ext.ext_exp - EXT_EXP_BIAS - LDBL_MANT_DIG - 1; + } + return u.extu_ext.ext_exp - EXT_EXP_BIAS; + +} + +#endif |
