e_scalb.c revision 8771baa10b2dc5bbedb08231d99c72cfd6abcb5b 
1
2/* @(#)e_scalb.c 1.3 95/01/18 */
3/*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunSoft, a Sun Microsystems, Inc. business.
8 * Permission to use, copy, modify, and distribute this
9 * software is freely granted, provided that this notice
10 * is preserved.
11 * ====================================================
12 */
13
14/*
15 * __ieee754_scalb(x, fn) is provide for
16 * passing various standard test suite. One
17 * should use ieee_scalbn() instead.
18 */
19
20#include "fdlibm.h"
21
22#ifdef _SCALB_INT
23#ifdef __STDC__
24	double __ieee754_scalb(double x, int fn)
25#else
26	double __ieee754_scalb(x,fn)
27	double x; int fn;
28#endif
29#else
30#ifdef __STDC__
31	double __ieee754_scalb(double x, double fn)
32#else
33	double __ieee754_scalb(x,fn)
34	double x, fn;
35#endif
36#endif
37{
38#ifdef _SCALB_INT
39	return ieee_scalbn(x,fn);
40#else
41	if (ieee_isnan(x)||ieee_isnan(fn)) return x*fn;
42	if (!ieee_finite(fn)) {
43	    if(fn>0.0) return x*fn;
44	    else       return x/(-fn);
45	}
46	if (ieee_rint(fn)!=fn) return (fn-fn)/(fn-fn);
47	if ( fn > 65000.0) return ieee_scalbn(x, 65000);
48	if (-fn > 65000.0) return ieee_scalbn(x,-65000);
49	return ieee_scalbn(x,(int)fn);
50#endif
51}
52