diff options
Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-128/e_coshl.c')
| -rw-r--r-- | REORG.TODO/sysdeps/ieee754/ldbl-128/e_coshl.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-128/e_coshl.c b/REORG.TODO/sysdeps/ieee754/ldbl-128/e_coshl.c new file mode 100644 index 0000000000..70a2fe3e84 --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/ldbl-128/e_coshl.c @@ -0,0 +1,110 @@ +/* + * ==================================================== + * 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. + * ==================================================== + */ + +/* Changes for 128-bit long double are + Copyright (C) 2001 Stephen L. Moshier <moshier@na-net.ornl.gov> + and are incorporated herein by permission of the author. The author + reserves the right to distribute this material elsewhere under different + copying permissions. These modifications are distributed here under + the following terms: + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* __ieee754_coshl(x) + * Method : + * mathematically coshl(x) if defined to be (exp(x)+exp(-x))/2 + * 1. Replace x by |x| (coshl(x) = coshl(-x)). + * 2. + * [ exp(x) - 1 ]^2 + * 0 <= x <= ln2/2 : coshl(x) := 1 + ------------------- + * 2*exp(x) + * + * exp(x) + 1/exp(x) + * ln2/2 <= x <= 22 : coshl(x) := ------------------- + * 2 + * 22 <= x <= lnovft : coshl(x) := expl(x)/2 + * lnovft <= x <= ln2ovft: coshl(x) := expl(x/2)/2 * expl(x/2) + * ln2ovft < x : coshl(x) := huge*huge (overflow) + * + * Special cases: + * coshl(x) is |x| if x is +INF, -INF, or NaN. + * only coshl(0)=1 is exact for finite x. + */ + +#include <math.h> +#include <math_private.h> + +static const _Float128 one = 1.0, half = 0.5, huge = L(1.0e4900), +ovf_thresh = L(1.1357216553474703894801348310092223067821E4); + +_Float128 +__ieee754_coshl (_Float128 x) +{ + _Float128 t, w; + int32_t ex; + ieee854_long_double_shape_type u; + + u.value = x; + ex = u.parts32.w0 & 0x7fffffff; + + /* Absolute value of x. */ + u.parts32.w0 = ex; + + /* x is INF or NaN */ + if (ex >= 0x7fff0000) + return x * x; + + /* |x| in [0,0.5*ln2], return 1+expm1l(|x|)^2/(2*expl(|x|)) */ + if (ex < 0x3ffd62e4) /* 0.3465728759765625 */ + { + if (ex < 0x3fb80000) /* |x| < 2^-116 */ + return one; /* cosh(tiny) = 1 */ + t = __expm1l (u.value); + w = one + t; + + return one + (t * t) / (w + w); + } + + /* |x| in [0.5*ln2,40], return (exp(|x|)+1/exp(|x|)/2; */ + if (ex < 0x40044000) + { + t = __ieee754_expl (u.value); + return half * t + half / t; + } + + /* |x| in [22, ln(maxdouble)] return half*exp(|x|) */ + if (ex <= 0x400c62e3) /* 11356.375 */ + return half * __ieee754_expl (u.value); + + /* |x| in [log(maxdouble), overflowthresold] */ + if (u.value <= ovf_thresh) + { + w = __ieee754_expl (half * u.value); + t = half * w; + return t * w; + } + + /* |x| > overflowthresold, cosh(x) overflow */ + return huge * huge; +} +strong_alias (__ieee754_coshl, __coshl_finite) |