diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128/s_scalbnl.c')
-rw-r--r-- | sysdeps/ieee754/ldbl-128/s_scalbnl.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128/s_scalbnl.c b/sysdeps/ieee754/ldbl-128/s_scalbnl.c new file mode 100644 index 0000000..c54f064 --- /dev/null +++ b/sysdeps/ieee754/ldbl-128/s_scalbnl.c @@ -0,0 +1,70 @@ +/* s_scalbnl.c -- long double version of s_scalbn.c. + * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz. + */ + +/* @(#)s_scalbn.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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 + +/* + * scalbnl (long double x, int n) + * scalbnl(x,n) returns x* 2**n computed by exponent + * manipulation rather than by actually performing an + * exponentiation or a multiplication. + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const long double +#else +static long double +#endif +two114 = 2.0769187434139310514121985316880384E+34L, /* 0x4071000000000000, 0 */ +twom114 = 4.8148248609680896326399448564623183E-35L, /* 0x3F8D000000000000, 0 */ +huge = 1.0E+4900L, +tiny = 1.0E-4900L; + +#ifdef __STDC__ + long double __scalbnl (long double x, int n) +#else + long double __scalbnl (x,n) + long double x; int n; +#endif +{ + int64_t k,hx,lx; + GET_LDOUBLE_WORDS64(hx,lx,x); + k = (hx>>48)&0x7fff; /* extract exponent */ + if (k==0) { /* 0 or subnormal x */ + if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */ + x *= two114; + GET_LDOUBLE_MSW64(hx,x); + k = ((hx>>48)&0x7fff) - 114; + } + if (k==0x7fff) return x+x; /* NaN or Inf */ + k = k+n; + if (n> 50000 || k > 0x7ffe) + return huge*__copysignl(huge,x); /* overflow */ + if (n< -50000) return tiny*__copysignl(tiny,x); /*underflow*/ + if (k > 0) /* normal result */ + {SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;} + if (k <= -114) + return tiny*__copysignl(tiny,x); /*underflow*/ + k += 114; /* subnormal result */ + SET_LDOUBLE_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); + return x*twom114; +} +weak_alias (__scalbnl, scalbnl) |