diff options
Diffstat (limited to 'sysdeps/libm-ieee754/e_acoshl.c')
| -rw-r--r-- | sysdeps/libm-ieee754/e_acoshl.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_acoshl.c b/sysdeps/libm-ieee754/e_acoshl.c new file mode 100644 index 0000000000..8af7c27aa7 --- /dev/null +++ b/sysdeps/libm-ieee754/e_acoshl.c @@ -0,0 +1,72 @@ +/* e_acoshl.c -- long double version of e_acosh.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. + * ==================================================== + */ + +#if defined(LIBM_SCCS) && !defined(lint) +static char rcsid[] = "$NetBSD: $"; +#endif + +/* __ieee754_acoshl(x) + * Method : + * Based on + * acoshl(x) = logl [ x + sqrtl(x*x-1) ] + * we have + * acoshl(x) := logl(x)+ln2, if x is large; else + * acoshl(x) := logl(2x-1/(sqrtl(x*x-1)+x)) if x>2; else + * acoshl(x) := log1pl(t+sqrtl(2.0*t+t*t)); where t=x-1. + * + * Special cases: + * acoshl(x) is NaN with signal if x<1. + * acoshl(NaN) is NaN without signal. + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const long double +#else +static long double +#endif +one = 1.0, +ln2 = 6.931471805599453094287e-01L; /* 0x3FFE, 0xB17217F7, 0xD1CF79AC */ + +#ifdef __STDC__ + long double __ieee754_acoshl(long double x) +#else + long double __ieee754_acoshl(x) + long double x; +#endif +{ + long double t; + u_int32_t se,i0,i1; + EXTRACT_LDOUBLE_WORDS(se,i0,i1,x); + if(se<0x3fff) { /* x < 1 */ + return (x-x)/(x-x); + } else if(hx >=0x401b) { /* x > 2**28 */ + if(hx >=0x7fff) { /* x is inf of NaN */ + return x+x; + } else + return __ieee754_logl(x)+ln2; /* acoshl(huge)=logl(2x) */ + } else if(((se-0x3fff)|i0|i1)==0) { + return 0.0; /* acosh(1) = 0 */ + } else if (hx > 0x4000) { /* 2**28 > x > 2 */ + t=x*x; + return __ieee754_logl(2.0*x-one/(x+__ieee754_sqrtl(t-one))); + } else { /* 1<x<2 */ + t = x-one; + return __log1pl(t+__sqrtl(2.0*t+t*t)); + } +} |