diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/s_scalbnl.c')
-rw-r--r-- | sysdeps/ieee754/ldbl-96/s_scalbnl.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-96/s_scalbnl.c b/sysdeps/ieee754/ldbl-96/s_scalbnl.c new file mode 100644 index 0000000..34c52e7 --- /dev/null +++ b/sysdeps/ieee754/ldbl-96/s_scalbnl.c @@ -0,0 +1,71 @@ +/* s_scalbnl.c -- long double version of s_scalbn.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 + +/* + * 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 +two63 = 4.50359962737049600000e+15, +twom63 = 1.08420217248550443400e-19, +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 +{ + int32_t k,es,hx,lx; + GET_LDOUBLE_WORDS(es,hx,lx,x); + k = es&0x7fff; /* extract exponent */ + if (k==0) { /* 0 or subnormal x */ + if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */ + x *= two63; + GET_LDOUBLE_EXP(es,x); + k = (hx&0x7fff) - 63; + } + 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); + if (k > 0) /* normal result */ + {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;} + if (k <= -63) + return tiny*__copysignl(tiny,x); /*underflow*/ + k += 63; /* subnormal result */ + SET_LDOUBLE_EXP(x,(es&0x8000)|k); + return x*twom63; +} +weak_alias (__scalbnl, scalbnl) |