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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)
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')
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diff --git a/sysdeps/libm-ieee754/e_atanh.c b/sysdeps/libm-ieee754/e_atanh.c
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+/* @(#)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;
+}