xref: /netbsd/lib/libm/src/w_powf.c (revision bf9ec67e)
1 /* w_powf.c -- float version of w_pow.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 #include <sys/cdefs.h>
17 #if defined(LIBM_SCCS) && !defined(lint)
18 __RCSID("$NetBSD: w_powf.c,v 1.6 2002/05/26 22:02:02 wiz Exp $");
19 #endif
20 
21 /*
22  * wrapper powf(x,y) return x**y
23  */
24 
25 #include "math.h"
26 #include "math_private.h"
27 
28 
29 float
30 powf(float x, float y)	/* wrapper powf */
31 {
32 #ifdef _IEEE_LIBM
33 	return  __ieee754_powf(x,y);
34 #else
35 	float z;
36 	z=__ieee754_powf(x,y);
37 	if(_LIB_VERSION == _IEEE_|| isnanf(y)) return z;
38 	if(isnanf(x)) {
39 	    if(y==(float)0.0)
40 	        /* powf(NaN,0.0) */
41 	        return (float)__kernel_standard((double)x,(double)y,142);
42 	    else
43 		return z;
44 	}
45 	if(x==(float)0.0){
46 	    if(y==(float)0.0)
47 	        /* powf(0.0,0.0) */
48 	        return (float)__kernel_standard((double)x,(double)y,120);
49 	    if(finitef(y)&&y<(float)0.0)
50 	        /* powf(0.0,negative) */
51 	        return (float)__kernel_standard((double)x,(double)y,123);
52 	    return z;
53 	}
54 	if(!finitef(z)) {
55 	    if(finitef(x)&&finitef(y)) {
56 	        if(isnanf(z))
57 		    /* powf neg**non-int */
58 	            return (float)__kernel_standard((double)x,(double)y,124);
59 	        else
60 		    /* powf overflow */
61 	            return (float)__kernel_standard((double)x,(double)y,121);
62 	    }
63 	}
64 	if(z==(float)0.0&&finitef(x)&&finitef(y))
65 	    /* powf underflow */
66 	    return (float)__kernel_standard((double)x,(double)y,122);
67 	return z;
68 #endif
69 }
70