nearbyint_test.c revision 293267 
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: stable/10/lib/msun/tests/nearbyint_test.c 293267 2016-01-06 20:21:40Z ngie $");
37
38#include <assert.h>
39#include <fenv.h>
40#include <math.h>
41#include <stdio.h>
42
43#include "test-utils.h"
44
45static int testnum;
46
47static 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. */
52double (*libnearbyint)(double) = nearbyint;
53float (*libnearbyintf)(float) = nearbyintf;
54long double (*libnearbyintl)(long double) = nearbyintl;
55#define nearbyintf libnearbyintf
56#define nearbyint libnearbyint
57#define nearbyintl libnearbyintl
58
59static 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
72static const int ntests = sizeof(tests) / sizeof(tests[0]);
73
74/* Get the appropriate result for the current rounding mode. */
75static float
76get_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
92static void
93test_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
120static void
121test_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
163int
164main(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