#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_scalbn.c,v 1.11 1999/07/02 15:37:43 simonb Exp $");
#endif
#define __DARWIN_UNIX03 1
#include "sys/cdefs.h"
#include "math.h"
#include "math_private.h"
static const double
two54 = 0x1.0p+54,
twom54 = 0x1.0p-54,
huge = 1.0e+300,
tiny = 1.0e-300;
double scalbn (double x, int n)
{
int32_t k,hx,lx;
EXTRACT_WORDS(hx,lx,x);
k = (hx&0x7ff00000)>>20;
if (k==0) {
if ((lx|(hx&0x7fffffff))==0) return x;
x *= two54;
GET_HIGH_WORD(hx,x);
k = ((hx&0x7ff00000)>>20) - 54;
if (n< -50000) return tiny*x;
}
if (k==0x7ff) return x+x;
k = k+n;
if (k > 0x7fe) return huge*copysign(huge,x);
if (k > 0)
{SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
if (k <= -54) {
if (n > 50000)
return huge*copysign(huge,x);
else return tiny*copysign(tiny,x);
}
k += 54;
SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
return x*twom54;
}
double scalb ( double x, double n )
{
int m;
if ( n > 2098.0 )
m = 2098.0;
else if ( n < -2099.0 )
m = -2099.0;
else m = (int) n;
return scalbn( x, m );
}