glibc/sysdeps/ieee754/ldbl-96/s_asinhl.c
Ulrich Drepper abfbdde177 Update.
1999-07-14 00:54:57 +00:00

71 lines
1.9 KiB
C

/* s_asinhl.c -- long double version of s_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
/* asinhl(x)
* Method :
* Based on
* asinhl(x) = signl(x) * logl [ |x| + sqrtl(x*x+1) ]
* we have
* asinhl(x) := x if 1+x*x=1,
* := signl(x)*(logl(x)+ln2)) for large |x|, else
* := signl(x)*logl(2|x|+1/(|x|+sqrtl(x*x+1))) if|x|>2, else
* := signl(x)*log1pl(|x| + x^2/(1 + sqrtl(1+x^2)))
*/
#include "math.h"
#include "math_private.h"
#ifdef __STDC__
static const long double
#else
static long double
#endif
one = 1.000000000000000000000e+00L, /* 0x3FFF, 0x00000000, 0x00000000 */
ln2 = 6.931471805599453094287e-01L, /* 0x3FFE, 0xB17217F7, 0xD1CF79AC */
huge= 1.000000000000000000e+4900L;
#ifdef __STDC__
long double __asinhl(long double x)
#else
long double __asinhl(x)
long double x;
#endif
{
long double t,w;
int32_t hx,ix;
GET_LDOUBLE_EXP(hx,x);
ix = hx&0x7fff;
if(ix==0x7fff) return x+x; /* x is inf or NaN */
if(ix< 0x3fde) { /* |x|<2**-34 */
if(huge+x>one) return x; /* return x inexact except 0 */
}
if(ix>0x4020) { /* |x| > 2**34 */
w = __ieee754_logl(fabsl(x))+ln2;
} else if (ix>0x4000) { /* 2**34 > |x| > 2.0 */
t = fabsl(x);
w = __ieee754_logl(2.0*t+one/(__ieee754_sqrtl(x*x+one)+t));
} else { /* 2.0 > |x| > 2**-28 */
t = x*x;
w =__log1pl(fabsl(x)+t/(one+__ieee754_sqrtl(one+t)));
}
if(hx&0x8000) return -w; else return w;
}
weak_alias (__asinhl, asinhl)