| /* 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 __scalblnl (long double x, long int n) |
| #else |
| long double __scalblnl (x,n) |
| long double x; long 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 (__scalblnl, scalblnl) |
