diff options
Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-96/e_atanhl.c')
| -rw-r--r-- | REORG.TODO/sysdeps/ieee754/ldbl-96/e_atanhl.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-96/e_atanhl.c b/REORG.TODO/sysdeps/ieee754/ldbl-96/e_atanhl.c new file mode 100644 index 0000000000..b99a83c6ee --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/ldbl-96/e_atanhl.c @@ -0,0 +1,69 @@ +/* s_atanhl.c -- long double version of s_atan.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. + * ==================================================== + */ + +/* __ieee754_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 <float.h> +#include <math.h> +#include <math_private.h> + +static const long double one = 1.0, huge = 1e4900L; + +static const long double zero = 0.0; + +long double +__ieee754_atanhl(long double x) +{ + long double t; + int32_t ix; + u_int32_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/zero; + if(ix<0x3fdf) { + math_force_eval(huge+x); + math_check_force_underflow (x); + return x; /* x<2**-32 */ + } + SET_LDOUBLE_EXP(x,ix); + if(ix<0x3ffe) { /* 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(se<=0x7fff) return t; else return -t; +} +strong_alias (__ieee754_atanhl, __atanhl_finite) |