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author | Jakub Jelinek <jakub@redhat.com> | 2007-07-12 18:26:36 +0000 |
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committer | Jakub Jelinek <jakub@redhat.com> | 2007-07-12 18:26:36 +0000 |
commit | 0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch) | |
tree | 2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /sysdeps/ieee754/ldbl-128ibm/e_atanhl.c | |
parent | 7d58530341304d403a6626d7f7a1913165fe2f32 (diff) | |
download | glibc-0ecb606cb6cf65de1d9fc8a919bceb4be476c602.zip glibc-0ecb606cb6cf65de1d9fc8a919bceb4be476c602.tar.gz glibc-0ecb606cb6cf65de1d9fc8a919bceb4be476c602.tar.bz2 |
2.5-18.1
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_atanhl.c')
-rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/e_atanhl.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_atanhl.c b/sysdeps/ieee754/ldbl-128ibm/e_atanhl.c new file mode 100644 index 0000000..a801bd6 --- /dev/null +++ b/sysdeps/ieee754/ldbl-128ibm/e_atanhl.c @@ -0,0 +1,79 @@ +/* @(#)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 long double one = 1.0L, huge = 1e300L; +#else +static long double one = 1.0L, huge = 1e300L; +#endif + +#ifdef __STDC__ +static const long double zero = 0.0L; +#else +static long double zero = 0.0L; +#endif + +#ifdef __STDC__ + long double __ieee754_atanhl(long double x) +#else + long double __ieee754_atanhl(x) + long double x; +#endif +{ + long double t; + int64_t hx,ix; + u_int64_t lx; + GET_LDOUBLE_WORDS64(hx,lx,x); + ix = hx&0x7fffffffffffffffLL; + if (ix >= 0x3ff0000000000000LL) { /* |x|>=1 */ + if (ix > 0x3ff0000000000000LL) + return (x-x)/(x-x); + t = fabsl (x); + if (t > one) + return (x-x)/(x-x); + if (t == one) + return x/zero; + } + if(ix<0x3e20000000000000LL&&(huge+x)>zero) return x; /* x<2**-29 */ + x = fabsl (x); + if(ix<0x3fe0000000000000LL) { /* x < 0.5 */ + t = x+x; + t = 0.5*__log1pl(t+t*x/(one-x)); + } else + t = 0.5*__log1pl((x+x)/(one-x)); + if(hx>=0) return t; else return -t; +} |