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authorjoerg <joerg@NetBSD.org>2011-08-03 14:13:07 +0000
committerjoerg <joerg@NetBSD.org>2011-08-03 14:13:07 +0000
commitf73a9c72a8ea0a66b7bfa17fd400c20a45b6da2c (patch)
tree108a805eafcf1919e8378fddf09a46b381c9065b /lib/libm/src
parent7c2bed2aa85a8ae35827ce5b121e3df125194305 (diff)
Add logbl(3).
Diffstat (limited to 'lib/libm/src')
-rw-r--r--lib/libm/src/s_logb.c6
-rw-r--r--lib/libm/src/s_logbl.c76
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