e_scalb.c revision 2116 
1/* @(#)e_scalb.c 5.1 93/09/24 */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13#ifndef lint
14static char rcsid[] = "$Id: e_scalb.c,v 1.4 1994/08/10 20:31:26 jtc Exp $";
15#endif
16
17/*
18 * __ieee754_scalb(x, fn) is provide for
19 * passing various standard test suite. One
20 * should use scalbn() instead.
21 */
22
23#include "math.h"
24#include "math_private.h"
25
26#ifdef _SCALB_INT
27#ifdef __STDC__
28	double __ieee754_scalb(double x, int fn)
29#else
30	double __ieee754_scalb(x,fn)
31	double x; int fn;
32#endif
33#else
34#ifdef __STDC__
35	double __ieee754_scalb(double x, double fn)
36#else
37	double __ieee754_scalb(x,fn)
38	double x, fn;
39#endif
40#endif
41{
42#ifdef _SCALB_INT
43	return scalbn(x,fn);
44#else
45	if (isnan(x)||isnan(fn)) return x*fn;
46	if (!finite(fn)) {
47	    if(fn>0.0) return x*fn;
48	    else       return x/(-fn);
49	}
50	if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
51	if ( fn > 65000.0) return scalbn(x, 65000);
52	if (-fn > 65000.0) return scalbn(x,-65000);
53	return scalbn(x,(int)fn);
54#endif
55}
56