1
2 /* @(#)e_scalb.c 5.1 93/09/24 */
3 /*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, 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 * 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 _NEED_FLOAT64
23
24 __float64
scalb64(__float64 x,__float64 fn)25 scalb64(__float64 x, __float64 fn)
26 {
27 if (isnan(fn) || isnan(x))
28 return x + fn;
29
30 if (isinf(fn)) {
31 if ((x == 0.0 && fn > 0.0) || (isinf(x) && fn < 0.0))
32 return __math_invalid(fn);
33 if (fn > 0.0)
34 return fn*x;
35 else
36 return x/(-fn);
37 }
38
39 if (rint64(fn) != fn)
40 return __math_invalid(fn);
41
42 if (fn > 4 * _FLOAT64_MAX_EXP)
43 fn = 4 * _FLOAT64_MAX_EXP;
44
45 if (fn < -4 * _FLOAT64_MAX_EXP)
46 fn = -4 * _FLOAT64_MAX_EXP;
47
48 return scalbn64(x, (int)fn);
49 }
50
51 _MATH_ALIAS_d_dd(scalb)
52
53 #endif /* _NEED_FLOAT64 */
54
