mirror of
https://github.com/fluencelabs/musl
synced 2025-06-05 11:01:37 +00:00
0cbb654791
zero, one, two, half are replaced by const literals The policy was to use the f suffix for float consts (1.0f), but don't use suffix for long double consts (these consts can be exactly represented as double).
65 lines
1.7 KiB
C
65 lines
1.7 KiB
C
/* origin: OpenBSD /usr/src/lib/libm/src/ld80/e_atanh.c */
|
|
/*
|
|
* ====================================================
|
|
* 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.
|
|
* ====================================================
|
|
*/
|
|
/* atanhl(x)
|
|
* Method :
|
|
* 1.Reduced x to positive by atanh(-x) = -atanh(x)
|
|
* 2.For x>=0.5
|
|
* 1 2x x
|
|
* atanhl(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
|
|
* 2 1 - x 1 - x
|
|
*
|
|
* For x<0.5
|
|
* atanhl(x) = 0.5*log1pl(2x+2x*x/(1-x))
|
|
*
|
|
* Special cases:
|
|
* atanhl(x) is NaN if |x| > 1 with signal;
|
|
* atanhl(NaN) is that NaN with no signal;
|
|
* atanhl(+-1) is +-INF with signal.
|
|
*/
|
|
|
|
#include "libm.h"
|
|
|
|
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
|
|
long double atanhl(long double x)
|
|
{
|
|
return atanh(x);
|
|
}
|
|
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
|
|
static const long double huge = 1e4900L;
|
|
|
|
long double atanhl(long double x)
|
|
{
|
|
long double t;
|
|
int32_t ix;
|
|
uint32_t se,i0,i1;
|
|
|
|
GET_LDOUBLE_WORDS(se, i0, i1, x);
|
|
ix = se & 0x7fff;
|
|
if ((ix+((((i0&0x7fffffff)|i1)|(-((i0&0x7fffffff)|i1)))>>31)) > 0x3fff)
|
|
/* |x| > 1 */
|
|
return (x-x)/(x-x);
|
|
if (ix == 0x3fff)
|
|
return x/0.0;
|
|
if (ix < 0x3fe3 && huge+x > 0.0) /* x < 2**-28 */
|
|
return x;
|
|
SET_LDOUBLE_EXP(x, ix);
|
|
if (ix < 0x3ffe) { /* x < 0.5 */
|
|
t = x + x;
|
|
t = 0.5*log1pl(t + t*x/(1.0 - x));
|
|
} else
|
|
t = 0.5*log1pl((x + x)/(1.0 - x));
|
|
if (se <= 0x7fff)
|
|
return t;
|
|
return -t;
|
|
}
|
|
#endif
|