#include <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: s_scalbn.c,v 1.11 1999/07/02 15:37:43 simonb Exp $");
#endif
#include "math.h"
#include "math_private.h"
static const double
two54 = 1.80143985094819840000e+16,
twom54 = 5.55111512312578270212e-17,
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;
}