glibc/sysdeps/libm-ieee754/s_tanhl.c
Ulrich Drepper 6952e59e25 update from main archive 970203
1997-02-04 02:08  Ulrich Drepper  <drepper@cygnus.com>

	* Version 2.0.1 net release.

1997-02-03 23:34  Stephen L Moshier  <moshier@world.std.com>

	* sysdeps/libm-ieee754/s_tanhl.c: Fix backwards result sign.

1997-02-03 19:59  Ulrich Drepper  <drepper@cygnus.com>

	* stdlib/getsubopt.c: Don't return `=' for suboption which has
	a parameter.  Reported by Gary L. Hennigan <glhenni@cs.sandia.gov>.

1997-02-03 18:20  Thorsten Kukuk  <kukuk@weber.uni-paderborn.de>

	* nis/rpcsvc/yp_proh.h (ypresp_key_val): Also change order of
	values as in yp.x and yp.h.

1997-02-03 16:58  Ulrich Drepper  <drepper@cygnus.com>

	* nis/rpcsvc/yp.x (struct ypresp_key_val): Revert patch from
	1997-02-03 02:17.  Sun's implementation internally corrects
	this bug but we don't want to hide this from the user.
	* nis/rpcsvc/yp.h: Likewise.

1997-02-01 18:28  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/unix/sysv/linux/net/ppp_defs.h: Protect against multiple
	inclusion.

1997-02-02 14:56  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* manual/nss.texi, manual/pattern.texi, manual/string.texi: Doc
	fixes.

1997-02-02 11:51  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* MakeTAGS (sysdep-sources, sysdep-headers): New variables.
	(all-sources, all-headers): Use them instead of $(sources) and
	$(headers) when searching in sysdep directories.

1997-02-02 11:49  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* Makerules (REAL_MAKE_VERSION): Use internal make function
	instead of shelling out.

1997-02-02 11:47  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* time/Makefile (install-test-data): Remove mkdir command, zic can
	handle that gracefully.

1997-02-03 14:07  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/m68k/asm-syntax.h: Add back file which got lost sometime
	somehow.

1997-02-02 07:46  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sunrpc/Makefile: Check $(cross-compiling) only after including
	../Makeconfig.
	($(objpfx)rpcsvc/%.h, $(objpfx)x%.c): Add empty command to force
	being considered as a rule.
	(generated): Add stamp files before the inclusion of Makerules to
	magically mark them as not being intermediate via the `generated'
	target.
1997-02-04 02:01:01 +00:00

93 lines
2.3 KiB
C

/* s_tanhl.c -- long double version of s_tanh.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
/* tanhl(x)
* Return the Hyperbolic Tangent of x
*
* Method :
* x -x
* e - e
* 0. tanhl(x) is defined to be -----------
* x -x
* e + e
* 1. reduce x to non-negative by tanhl(-x) = -tanhl(x).
* 2. 0 <= x <= 2**-55 : tanhl(x) := x*(one+x)
* -t
* 2**-55 < x <= 1 : tanhl(x) := -----; t = expm1l(-2x)
* t + 2
* 2
* 1 <= x <= 23.0 : tanhl(x) := 1- ----- ; t=expm1l(2x)
* t + 2
* 23.0 < x <= INF : tanhl(x) := 1.
*
* Special cases:
* tanhl(NaN) is NaN;
* only tanhl(0)=0 is exact for finite argument.
*/
#include "math.h"
#include "math_private.h"
#ifdef __STDC__
static const long double one=1.0, two=2.0, tiny = 1.0e-4900L;
#else
static long double one=1.0, two=2.0, tiny = 1.0e-4900L;
#endif
#ifdef __STDC__
long double __tanhl(long double x)
#else
long double __tanhl(x)
long double x;
#endif
{
long double t,z;
int32_t se;
u_int32_t j0,j1,ix;
/* High word of |x|. */
GET_LDOUBLE_WORDS(se,j0,j1,x);
ix = se&0x7fff;
/* x is INF or NaN */
if(ix==0x7fff) {
if (se>=0x7fff) return one/x+one; /* tanhl(+-inf)=+-1 */
else return one/x-one; /* tanhl(NaN) = NaN */
}
/* |x| < 23 */
if (ix < 0x4003 || (ix == 0x4003 && j0 < 0xb8000000u)) {/* |x|<23 */
if (ix<0x3fc8) /* |x|<2**-55 */
return x*(one+x); /* tanh(small) = small */
if (ix>=0x3fff) { /* |x|>=1 */
t = __expm1l(two*fabsl(x));
z = one - two/(t+two);
} else {
t = __expm1l(-two*fabsl(x));
z= -t/(t+two);
}
/* |x| > 23, return +-1 */
} else {
z = one - tiny; /* raised inexact flag */
}
return (se>0x7fff)? -z: z;
}
weak_alias (__tanhl, tanhl)