aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--ChangeLog3
-rw-r--r--NEWS2
-rw-r--r--sysdeps/ieee754/ldbl-128/e_atanhl.c84
3 files changed, 88 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index de7c4dc464..76f4721d79 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
2001-07-30 Andreas Jaeger <aj@suse.de>
+ * sysdeps/ieee754/ldbl-128/e_atanhl.c: New file, contributed by
+ Stephen L Moshier.
+
* posix/regex.c: Declare wcs functions only if compiling with
MBS_SUPPORT.
Don't use #elif for traditional C.
diff --git a/NEWS b/NEWS
index 5144dc0610..22de43b539 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ Please send GNU C library bug reports using the `glibcbug' script to
Version 2.2.4
* Stephen Moshier implemented cosh, expm1, log1p, acos, sinh, tanh,
- asinh for the 128-bit long double format.
+ asinh, atanh for the 128-bit long double format.
* Bruno Haible updated all the code handling Unicode in some form to
support Unicode 3.1.
diff --git a/sysdeps/ieee754/ldbl-128/e_atanhl.c b/sysdeps/ieee754/ldbl-128/e_atanhl.c
new file mode 100644
index 0000000000..dd681c847c
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128/e_atanhl.c
@@ -0,0 +1,84 @@
+/* s_atanhl.c -- long double version of s_atan.c.
+ * Conversion to long double by Ulrich Drepper,
+ * Cygnus Support, drepper@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: $";
+#endif
+
+/* __ieee754_atanhl(x)
+ * Method :
+ * 1.Reduced x to positive by atanh(-x) = -atanh(x)
+ * 2.For x>=0.5
+ * 1 2x x
+ * atanhl(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
+ * 2 1 - x 1 - x
+ *
+ * For x<0.5
+ * atanhl(x) = 0.5*log1pl(2x+2x*x/(1-x))
+ *
+ * Special cases:
+ * atanhl(x) is NaN if |x| > 1 with signal;
+ * atanhl(NaN) is that NaN with no signal;
+ * atanhl(+-1) is +-INF with signal.
+ *
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double one = 1.0L, huge = 1e4900L;
+#else
+static long double one = 1.0L, huge = 1e4900L;
+#endif
+
+#ifdef __STDC__
+static const long double zero = 0.0L;
+#else
+static double long zero = 0.0L;
+#endif
+
+#ifdef __STDC__
+ long double __ieee754_atanhl(long double x)
+#else
+ long double __ieee754_atanhl(x)
+ long double x;
+#endif
+{
+ long double t;
+ u_int32_t jx, ix;
+ ieee854_long_double_shape_type u;
+
+ u.value = x;
+ jx = u.parts32.w0;
+ ix = jx & 0x7fffffff;
+ u.parts32.w0 = ix;
+ if (ix >= 0x3fff0000) /* |x| >= 1.0 or infinity or NaN */
+ {
+ if (u.value == one)
+ return x/zero;
+ else
+ return (x-x)/(x-x);
+ }
+ if(ix<0x3fc60000 && (huge+x)>zero) return x; /* x < 2^-57 */
+
+ if(ix<0x3ffe0000) { /* x < 0.5 */
+ t = u.value+u.value;
+ t = 0.5*__log1pl(t+t*u.value/(one-u.value));
+ } else
+ t = 0.5*__log1pl((u.value+u.value)/(one-u.value));
+ if(jx & 0x80000000) return -t; else return t;
+}