xref: /minix3/lib/libm/src/w_expf.c (revision 2fe8fb192fe7e8720e3e7a77f928da545e872a6a)
1*2fe8fb19SBen Gras /* w_expf.c -- float version of w_exp.c.
2*2fe8fb19SBen Gras  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3*2fe8fb19SBen Gras  */
4*2fe8fb19SBen Gras 
5*2fe8fb19SBen Gras /*
6*2fe8fb19SBen Gras  * ====================================================
7*2fe8fb19SBen Gras  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8*2fe8fb19SBen Gras  *
9*2fe8fb19SBen Gras  * Developed at SunPro, a Sun Microsystems, Inc. business.
10*2fe8fb19SBen Gras  * Permission to use, copy, modify, and distribute this
11*2fe8fb19SBen Gras  * software is freely granted, provided that this notice
12*2fe8fb19SBen Gras  * is preserved.
13*2fe8fb19SBen Gras  * ====================================================
14*2fe8fb19SBen Gras  */
15*2fe8fb19SBen Gras 
16*2fe8fb19SBen Gras #include <sys/cdefs.h>
17*2fe8fb19SBen Gras #if defined(LIBM_SCCS) && !defined(lint)
18*2fe8fb19SBen Gras __RCSID("$NetBSD: w_expf.c,v 1.7 2007/08/20 16:01:40 drochner Exp $");
19*2fe8fb19SBen Gras #endif
20*2fe8fb19SBen Gras 
21*2fe8fb19SBen Gras /*
22*2fe8fb19SBen Gras  * wrapper expf(x)
23*2fe8fb19SBen Gras  */
24*2fe8fb19SBen Gras 
25*2fe8fb19SBen Gras #include "namespace.h"
26*2fe8fb19SBen Gras #include "math.h"
27*2fe8fb19SBen Gras #include "math_private.h"
28*2fe8fb19SBen Gras 
29*2fe8fb19SBen Gras #ifdef __weak_alias
30*2fe8fb19SBen Gras __weak_alias(expf, _expf)
31*2fe8fb19SBen Gras #endif
32*2fe8fb19SBen Gras 
33*2fe8fb19SBen Gras static const float
34*2fe8fb19SBen Gras o_threshold=  8.8721679688e+01,  /* 0x42b17180 */
35*2fe8fb19SBen Gras u_threshold= -1.0397208405e+02;  /* 0xc2cff1b5 */
36*2fe8fb19SBen Gras 
37*2fe8fb19SBen Gras float
expf(float x)38*2fe8fb19SBen Gras expf(float x)		/* wrapper expf */
39*2fe8fb19SBen Gras {
40*2fe8fb19SBen Gras #ifdef _IEEE_LIBM
41*2fe8fb19SBen Gras 	return __ieee754_expf(x);
42*2fe8fb19SBen Gras #else
43*2fe8fb19SBen Gras 	float z;
44*2fe8fb19SBen Gras 	z = __ieee754_expf(x);
45*2fe8fb19SBen Gras 	if(_LIB_VERSION == _IEEE_) return z;
46*2fe8fb19SBen Gras 	if(finitef(x)) {
47*2fe8fb19SBen Gras 	    if(x>o_threshold)
48*2fe8fb19SBen Gras 	        /* exp overflow */
49*2fe8fb19SBen Gras 	        return (float)__kernel_standard((double)x,(double)x,106);
50*2fe8fb19SBen Gras 	    else if(x<u_threshold)
51*2fe8fb19SBen Gras 	        /* exp underflow */
52*2fe8fb19SBen Gras 	        return (float)__kernel_standard((double)x,(double)x,107);
53*2fe8fb19SBen Gras 	}
54*2fe8fb19SBen Gras 	return z;
55*2fe8fb19SBen Gras #endif
56*2fe8fb19SBen Gras }
57