xref: /freebsd/lib/msun/src/s_fminimum_magf.c (revision 4e30c12973c73539bef01be3870a90b6346141e8)
1 /*
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <math.h>
30 
31 #include "fpmath.h"
32 
33 #ifdef USE_BUILTIN_FMINIMUM_MAGF
34 float
fminimum_magf(float x,float y)35 fminimum_magf(float x, float y)
36 {
37 	return (__builtin_fminimum_magf(x, y));
38 }
39 #else
40 float
fminimum_magf(float x,float y)41 fminimum_magf(float x, float y)
42 {
43 	union IEEEf2bits u[2];
44 
45 	u[0].f = x;
46 	u[1].f = y;
47 
48 	/* Handle NaN according to ISO/IEC 60559. NaN argument -> NaN return */
49 	if (u[0].bits.exp == 255 && u[0].bits.man != 0 ||
50 	    u[1].bits.exp == 255 && u[1].bits.man != 0)
51 		return (NAN);
52 
53 	float ax = fabsf(x);
54 	float ay = fabsf(y);
55 
56 	if (ay < ax)
57 		return (y);
58 	if (ax < ay)
59 		return (x);
60 
61 	/* If magnitudes are equal, we break the tie with the sign */
62 	if (u[0].bits.sign != u[1].bits.sign)
63 		return (u[u[1].bits.sign].f);
64 
65 	return (x);
66 }
67 #endif
68 
69 
70