about summary refs log tree commit diff
path: root/sysdeps/libm-ieee754/e_atanh.c
diff options
context:
space:
mode:
authorRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
committerRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
commitf7eac6eb504f4baf13dbb4d26717942df050ebe6 (patch)
tree95ff129c06c7f6f246a5e2bfa489ba6382659d19 /sysdeps/libm-ieee754/e_atanh.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
downloadglibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.gz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.xz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.zip
Mon Mar 4 20:54:40 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
	* Makeconfig ($(common-objpfx)config.make): Depend on config.h.in.


Mon Mar  4 17:35:09 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	* hurd/catch-signal.c (hurd_safe_memmove): New function.
	(hurd_safe_copyin, hurd_safe_copyout): New functions.
	* hurd/hurd/sigpreempt.h: Declare them.

Sun Mar  3 08:43:44 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	Replace math code with fdlibm from Sun as modified for netbsd by
	JT Conklin and Ian Taylor, including x86 FPU support.
	* sysdeps/libm-ieee754, sysdeps/libm-i387: New directories.
	* math/math_private.h: New file.
	* sysdeps/i386/fpu/Implies: New file.
	* sysdeps/ieee754/Implies: New file.
	* math/machine/asm.h, math/machine/endian.h: New files.
	* math/Makefile, math/math.h: Rewritten.
	* mathcalls.h, math/mathcalls.h: New file, broken out of math.h.
	* math/finite.c: File removed.
	* sysdeps/generic/Makefile [$(subdir)=math]: Frobnication removed.

	* math/test-math.c: Include errno.h and string.h.

	* sysdeps/unix/bsd/dirstream.h: File removed.
	* sysdeps/unix/bsd/readdir.c: File removed.
Diffstat (limited to 'sysdeps/libm-ieee754/e_atanh.c')
-rw-r--r--sysdeps/libm-ieee754/e_atanh.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_atanh.c b/sysdeps/libm-ieee754/e_atanh.c
new file mode 100644
index 0000000000..fa4fe675c9
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_atanh.c
@@ -0,0 +1,74 @@
+/* @(#)e_atanh.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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: e_atanh.c,v 1.8 1995/05/10 20:44:55 jtc Exp $";
+#endif
+
+/* __ieee754_atanh(x)
+ * Method :
+ *    1.Reduced x to positive by atanh(-x) = -atanh(x)
+ *    2.For x>=0.5
+ *                  1              2x                          x
+ *	atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
+ *                  2             1 - x                      1 - x
+ *	
+ * 	For x<0.5
+ *	atanh(x) = 0.5*log1p(2x+2x*x/(1-x))
+ *
+ * Special cases:
+ *	atanh(x) is NaN if |x| > 1 with signal;
+ *	atanh(NaN) is that NaN with no signal;
+ *	atanh(+-1) is +-INF with signal.
+ *
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const double one = 1.0, huge = 1e300;
+#else
+static double one = 1.0, huge = 1e300;
+#endif
+
+#ifdef __STDC__
+static const double zero = 0.0;
+#else
+static double zero = 0.0;
+#endif
+
+#ifdef __STDC__
+	double __ieee754_atanh(double x)
+#else
+	double __ieee754_atanh(x)
+	double x;
+#endif
+{
+	double t;
+	int32_t hx,ix;
+	u_int32_t lx;
+	EXTRACT_WORDS(hx,lx,x);
+	ix = hx&0x7fffffff;
+	if ((ix|((lx|(-lx))>>31))>0x3ff00000) /* |x|>1 */
+	    return (x-x)/(x-x);
+	if(ix==0x3ff00000) 
+	    return x/zero;
+	if(ix<0x3e300000&&(huge+x)>zero) return x;	/* x<2**-28 */
+	SET_HIGH_WORD(x,ix);
+	if(ix<0x3fe00000) {		/* x < 0.5 */
+	    t = x+x;
+	    t = 0.5*__log1p(t+t*x/(one-x));
+	} else 
+	    t = 0.5*__log1p((x+x)/(one-x));
+	if(hx>=0) return t; else return -t;
+}