/* sinhq.c -- __float128 version of e_sinh.c. | |

* Conversion to __float128 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. | |

* ==================================================== | |

*/ | |

/* Changes for 128-bit __float128 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, write to the Free Software | |

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ | |

/* sinhq(x) | |

* Method : | |

* mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2 | |

* 1. Replace x by |x| (sinhq(-x) = -sinhq(x)). | |

* 2. | |

* E + E/(E+1) | |

* 0 <= x <= 25 : sinhq(x) := --------------, E=expm1q(x) | |

* 2 | |

* | |

* 25 <= x <= lnovft : sinhq(x) := expq(x)/2 | |

* lnovft <= x <= ln2ovft: sinhq(x) := expq(x/2)/2 * expq(x/2) | |

* ln2ovft < x : sinhq(x) := x*shuge (overflow) | |

* | |

* Special cases: | |

* sinhq(x) is |x| if x is +INF, -INF, or NaN. | |

* only sinhq(0)=0 is exact for finite x. | |

*/ | |

#include "quadmath-imp.h" | |

static const __float128 one = 1.0, shuge = 1.0e4931Q, | |

ovf_thresh = 1.1357216553474703894801348310092223067821E4Q; | |

__float128 | |

sinhq (__float128 x) | |

{ | |

__float128 t, w, h; | |

uint32_t jx, ix; | |

ieee854_float128 u; | |

/* Words of |x|. */ | |

u.value = x; | |

jx = u.words32.w0; | |

ix = jx & 0x7fffffff; | |

/* x is INF or NaN */ | |

if (ix >= 0x7fff0000) | |

return x + x; | |

h = 0.5Q; | |

if (jx & 0x80000000) | |

h = -h; | |

/* Absolute value of x. */ | |

u.words32.w0 = ix; | |

/* |x| in [0,40], return sign(x)*0.5*(E+E/(E+1))) */ | |

if (ix <= 0x40044000) | |

{ | |

if (ix < 0x3fc60000) /* |x| < 2^-57 */ | |

{ | |

math_check_force_underflow (x); | |

if (shuge + x > one) | |

return x; /* sinh(tiny) = tiny with inexact */ | |

} | |

t = expm1q (u.value); | |

if (ix < 0x3fff0000) | |

return h * (2.0Q * t - t * t / (t + one)); | |

return h * (t + t / (t + one)); | |

} | |

/* |x| in [40, log(maxdouble)] return 0.5*exp(|x|) */ | |

if (ix <= 0x400c62e3) /* 11356.375 */ | |

return h * expq (u.value); | |

/* |x| in [log(maxdouble), overflowthreshold] | |

Overflow threshold is log(2 * maxdouble). */ | |

if (u.value <= ovf_thresh) | |

{ | |

w = expq (0.5Q * u.value); | |

t = h * w; | |

return t * w; | |

} | |

/* |x| > overflowthreshold, sinhq(x) overflow */ | |

return x * shuge; | |

} |