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e_scalb.c
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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 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 scalbn(x,fn);
40 #else
41  if (isnan(x)||isnan(fn)) return x*fn;
42  if (!finite(fn)) {
43  if(fn>0.0) return x*fn;
44  else return x/(-fn);
45  }
46  if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
47  if ( fn > 65000.0) return scalbn(x, 65000);
48  if (-fn > 65000.0) return scalbn(x,-65000);
49  return scalbn(x,(int)fn);
50 #endif
51 }