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Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/ldbl-96/e_acoshl.c')
| -rw-r--r-- | REORG.TODO/sysdeps/ieee754/ldbl-96/e_acoshl.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/ldbl-96/e_acoshl.c b/REORG.TODO/sysdeps/ieee754/ldbl-96/e_acoshl.c new file mode 100644 index 0000000000..cf9a6db0ef --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/ldbl-96/e_acoshl.c @@ -0,0 +1,61 @@ +/* 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. + * ==================================================== + */ + +/* __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> + +static const long double +one = 1.0, +ln2 = 6.931471805599453094287e-01L; /* 0x3FFE, 0xB17217F7, 0xD1CF79AC */ + +long double +__ieee754_acoshl(long double x) +{ + long double t; + u_int32_t se,i0,i1; + GET_LDOUBLE_WORDS(se,i0,i1,x); + if(se<0x3fff || se & 0x8000) { /* x < 1 */ + return (x-x)/(x-x); + } else if(se >=0x401d) { /* x > 2**30 */ + if(se >=0x7fff) { /* x is inf of NaN */ + return x+x; + } else + return __ieee754_logl(x)+ln2; /* acoshl(huge)=logl(2x) */ + } else if(((se-0x3fff)|(i0^0x80000000)|i1)==0) { + return 0.0; /* acosh(1) = 0 */ + } else if (se > 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+__ieee754_sqrtl(2.0*t+t*t)); + } +} +strong_alias (__ieee754_acoshl, __acoshl_finite) |