1 /* @(#)w_exp.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 #include <sys/cdefs.h>
14 #if defined(LIBM_SCCS) && !defined(lint)
15 __RCSID("$NetBSD: w_exp.c,v 1.10 2007/08/20 16:01:40 drochner Exp $");
16 #endif
17
18 /*
19 * wrapper exp(x)
20 */
21
22 #include "namespace.h"
23 #include "math.h"
24 #include "math_private.h"
25
26 #ifdef __weak_alias
27 __weak_alias(exp, _exp)
28 #endif
29
30 static const double
31 o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */
32 u_threshold= -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */
33
34 double
exp(double x)35 exp(double x) /* wrapper exp */
36 {
37 #ifdef _IEEE_LIBM
38 return __ieee754_exp(x);
39 #else
40 double z;
41 z = __ieee754_exp(x);
42 if(_LIB_VERSION == _IEEE_) return z;
43 if(finite(x)) {
44 if(x>o_threshold)
45 return __kernel_standard(x,x,6); /* exp overflow */
46 else if(x<u_threshold)
47 return __kernel_standard(x,x,7); /* exp underflow */
48 }
49 return z;
50 #endif
51 }
52