mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 11:11:04 +00:00
92 lines
2.5 KiB
C
92 lines
2.5 KiB
C
/* e_asinhl.c -- long double version of e_asinh.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_sinhl(x)
|
|
* Method :
|
|
* mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2
|
|
* 1. Replace x by |x| (sinhl(-x) = -sinhl(x)).
|
|
* 2.
|
|
* E + E/(E+1)
|
|
* 0 <= x <= 25 : sinhl(x) := --------------, E=expm1l(x)
|
|
* 2
|
|
*
|
|
* 25 <= x <= lnovft : sinhl(x) := expl(x)/2
|
|
* lnovft <= x <= ln2ovft: sinhl(x) := expl(x/2)/2 * expl(x/2)
|
|
* ln2ovft < x : sinhl(x) := x*shuge (overflow)
|
|
*
|
|
* Special cases:
|
|
* sinhl(x) is |x| if x is +INF, -INF, or NaN.
|
|
* only sinhl(0)=0 is exact for finite x.
|
|
*/
|
|
|
|
#include "math.h"
|
|
#include "math_private.h"
|
|
|
|
#ifdef __STDC__
|
|
static const long double one = 1.0, shuge = 1.0e4931L;
|
|
#else
|
|
static long double one = 1.0, shuge = 1.0e4931L;
|
|
#endif
|
|
|
|
#ifdef __STDC__
|
|
long double __ieee754_sinhl(long double x)
|
|
#else
|
|
long double __ieee754_sinhl(x)
|
|
long double x;
|
|
#endif
|
|
{
|
|
long double t,w,h;
|
|
u_int32_t jx,ix,i0,i1;
|
|
|
|
/* Words of |x|. */
|
|
GET_LDOUBLE_WORDS(jx,i0,i1,x);
|
|
ix = jx&0x7fff;
|
|
|
|
/* x is INF or NaN */
|
|
if(ix==0x7fff) return x+x;
|
|
|
|
h = 0.5;
|
|
if (jx & 0x8000) h = -h;
|
|
/* |x| in [0,25], return sign(x)*0.5*(E+E/(E+1))) */
|
|
if (ix < 0x4003 || (ix == 0x4003 && i0 <= 0xc8000000)) { /* |x|<25 */
|
|
if (ix<0x3fdf) /* |x|<2**-32 */
|
|
if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
|
|
t = __expm1l(fabsl(x));
|
|
if(ix<0x3fff) return h*(2.0*t-t*t/(t+one));
|
|
return h*(t+t/(t+one));
|
|
}
|
|
|
|
/* |x| in [25, log(maxdouble)] return 0.5*exp(|x|) */
|
|
if (ix < 0x400c || (ix == 0x400c && i0 < 0xb17217f7))
|
|
return h*__ieee754_expl(fabsl(x));
|
|
|
|
/* |x| in [log(maxdouble), overflowthreshold] */
|
|
if (ix<0x400c || (ix == 0x400c && (i0 < 0xb174ddc0
|
|
|| (i0 == 0xb174ddc0
|
|
&& i1 <= 0x31aec0ea)))) {
|
|
w = __ieee754_expl(0.5*fabsl(x));
|
|
t = h*w;
|
|
return t*w;
|
|
}
|
|
|
|
/* |x| > overflowthreshold, sinhl(x) overflow */
|
|
return x*shuge;
|
|
}
|