xref: /freebsd/lib/msun/tests/nearbyint_test.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /*-
2  * Copyright (c) 2010 David Schultz <das@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 /*
28  * Tests for nearbyint{,f,l}()
29  *
30  * TODO:
31  * - adapt tests for rint(3)
32  * - tests for harder values (more mantissa bits than float)
33  */
34 
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <assert.h>
39 #include <fenv.h>
40 #include <math.h>
41 #include <stdio.h>
42 
43 #include "test-utils.h"
44 
45 static int testnum;
46 
47 static const int rmodes[] = {
48 	FE_TONEAREST, FE_DOWNWARD, FE_UPWARD, FE_TOWARDZERO,
49 };
50 
51 /* Make sure we're testing the library, not some broken compiler built-ins. */
52 double (*libnearbyint)(double) = nearbyint;
53 float (*libnearbyintf)(float) = nearbyintf;
54 long double (*libnearbyintl)(long double) = nearbyintl;
55 #define nearbyintf libnearbyintf
56 #define nearbyint libnearbyint
57 #define nearbyintl libnearbyintl
58 
59 static const struct {
60 	float in;
61 	float out[3];	/* one answer per rounding mode except towardzero */
62 } tests[] = {
63 /* input	output (expected) */
64     { 0.0,	{ 0.0, 0.0, 0.0 }},
65     { 0.5,	{ 0.0, 0.0, 1.0 }},
66     { M_PI,	{ 3.0, 3.0, 4.0 }},
67     { 65536.5,	{ 65536, 65536, 65537 }},
68     { INFINITY,	{ INFINITY, INFINITY, INFINITY }},
69     { NAN,	{ NAN, NAN, NAN }},
70 };
71 
72 static const int ntests = sizeof(tests) / sizeof(tests[0]);
73 
74 /* Get the appropriate result for the current rounding mode. */
75 static float
76 get_output(int testindex, int rmodeindex, int negative)
77 {
78 	double out;
79 
80 	if (negative) {	/* swap downwards and upwards if input is negative */
81 		if (rmodeindex == 1)
82 			rmodeindex = 2;
83 		else if (rmodeindex == 2)
84 			rmodeindex = 1;
85 	}
86 	if (rmodeindex == 3) /* FE_TOWARDZERO uses the value for downwards */
87 		rmodeindex = 1;
88 	out = tests[testindex].out[rmodeindex];
89 	return (negative ? -out : out);
90 }
91 
92 static void
93 test_nearby(int testindex)
94 {
95 	float in, out;
96 	int i;
97 
98 	for (i = 0; i < sizeof(rmodes) / sizeof(rmodes[0]); i++) {
99 		fesetround(rmodes[i]);
100 		feclearexcept(ALL_STD_EXCEPT);
101 
102 		in = tests[testindex].in;
103 		out = get_output(testindex, i, 0);
104 		assert(fpequal(out, libnearbyintf(in)));
105 		assert(fpequal(out, nearbyint(in)));
106 		assert(fpequal(out, nearbyintl(in)));
107 		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
108 
109 		in = -tests[testindex].in;
110 		out = get_output(testindex, i, 1);
111 		assert(fpequal(out, nearbyintf(in)));
112 		assert(fpequal(out, nearbyint(in)));
113 		assert(fpequal(out, nearbyintl(in)));
114 		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
115 	}
116 
117 	printf("ok %d\t\t# nearbyint(+%g)\n", testnum++, in);
118 }
119 
120 static void
121 test_modf(int testindex)
122 {
123 	float in, out;
124 	float ipartf, ipart_expected;
125 	double ipart;
126 	long double ipartl;
127 	int i;
128 
129 	for (i = 0; i < sizeof(rmodes) / sizeof(rmodes[0]); i++) {
130 		fesetround(rmodes[i]);
131 		feclearexcept(ALL_STD_EXCEPT);
132 
133 		in = tests[testindex].in;
134 		ipart_expected = tests[testindex].out[1];
135 		out = copysignf(
136 		    isinf(ipart_expected) ? 0.0 : in - ipart_expected, in);
137 		ipartl = ipart = ipartf = 42.0;
138 
139 		assert(fpequal(out, modff(in, &ipartf)));
140 		assert(fpequal(ipart_expected, ipartf));
141 		assert(fpequal(out, modf(in, &ipart)));
142 		assert(fpequal(ipart_expected, ipart));
143 		assert(fpequal(out, modfl(in, &ipartl)));
144 		assert(fpequal(ipart_expected, ipartl));
145 		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
146 
147 		in = -in;
148 		ipart_expected = -ipart_expected;
149 		out = -out;
150 		ipartl = ipart = ipartf = 42.0;
151 		assert(fpequal(out, modff(in, &ipartf)));
152 		assert(fpequal(ipart_expected, ipartf));
153 		assert(fpequal(out, modf(in, &ipart)));
154 		assert(fpequal(ipart_expected, ipart));
155 		assert(fpequal(out, modfl(in, &ipartl)));
156 		assert(fpequal(ipart_expected, ipartl));
157 		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
158 	}
159 
160 	printf("ok %d\t\t# modf(+%g)\n", testnum++, in);
161 }
162 
163 int
164 main(int argc, char *argv[])
165 {
166 	int i;
167 
168 	printf("1..%d\n", ntests * 2);
169 	testnum = 1;
170 	for (i = 0; i < ntests; i++) {
171 		test_nearby(i);
172 		test_modf(i);
173 	}
174 
175 	return (0);
176 }
177