diff options
Diffstat (limited to 'lib/msun/src/e_atanhl.c')
-rw-r--r-- | lib/msun/src/e_atanhl.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/lib/msun/src/e_atanhl.c b/lib/msun/src/e_atanhl.c new file mode 100644 index 0000000..11d56ea --- /dev/null +++ b/lib/msun/src/e_atanhl.c @@ -0,0 +1,74 @@ +/* from: FreeBSD: head/lib/msun/src/e_atanh.c 176451 2008-02-22 02:30:36Z das */ + +/* @(#)e_atanh.c 1.3 95/01/18 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunSoft, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + * + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * See e_atanh.c for complete comments. + * + * Converted to long double by David Schultz <das@FreeBSD.ORG> and + * Bruce D. Evans. + */ + +#include <float.h> +#ifdef __i386__ +#include <ieeefp.h> +#endif + +#include "fpmath.h" +#include "math.h" +#include "math_private.h" + +/* EXP_TINY is the threshold below which we use atanh(x) ~= x. */ +#if LDBL_MANT_DIG == 64 +#define EXP_TINY -34 +#elif LDBL_MANT_DIG == 113 +#define EXP_TINY -58 +#else +#error "Unsupported long double format" +#endif + +#if LDBL_MAX_EXP != 0x4000 +/* We also require the usual expsign encoding. */ +#error "Unsupported long double format" +#endif + +#define BIAS (LDBL_MAX_EXP - 1) + +static const double one = 1.0, huge = 1e300; +static const double zero = 0.0; + +long double +atanhl(long double x) +{ + long double t; + uint16_t hx, ix; + + ENTERI(); + GET_LDBL_EXPSIGN(hx, x); + ix = hx & 0x7fff; + if (ix >= 0x3fff) /* |x| >= 1, or NaN or misnormal */ + RETURNI(fabsl(x) == 1 ? x / zero : (x - x) / (x - x)); + if (ix < BIAS + EXP_TINY && (huge + x) > zero) + RETURNI(x); /* x is tiny */ + SET_LDBL_EXPSIGN(x, ix); + if (ix < 0x3ffe) { /* |x| < 0.5, or misnormal */ + t = x+x; + t = 0.5*log1pl(t+t*x/(one-x)); + } else + t = 0.5*log1pl((x+x)/(one-x)); + RETURNI((hx & 0x8000) == 0 ? t : -t); +} |