1/* origin: FreeBSD /usr/src/lib/msun/src/e_scalb.c */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunSoft, 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 * scalb(x, fn) is provide for
14 * passing various standard test suite. One
15 * should use scalbn() instead.
16 */
17
18#define _GNU_SOURCE
19#include <math.h>
20
21double scalb(double x, double fn)
22{
23 if (isnan(x) || isnan(fn))
24 return x*fn;
25 if (!isfinite(fn)) {
26 if (fn > 0.0)
27 return x*fn;
28 else
29 return x/(-fn);
30 }
31 if (rint(fn) != fn) return (fn-fn)/(fn-fn);
32 if ( fn > 65000.0) return scalbn(x, 65000);
33 if (-fn > 65000.0) return scalbn(x,-65000);
34 return scalbn(x,(int)fn);
35}