nearbyint_test.c revision 226605 
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: head/tools/regression/lib/msun/test-nearbyint.c 226605 2011-10-21 06:36:40Z das $");
37
38#include <assert.h>
39#include <fenv.h>
40#include <math.h>
41#include <stdio.h>
42
43#define	ALL_STD_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
44			 FE_OVERFLOW | FE_UNDERFLOW)
45
46static int testnum;
47
48static const int rmodes[] = {
49	FE_TONEAREST, FE_DOWNWARD, FE_UPWARD, FE_TOWARDZERO,
50};
51
52static const struct {
53	float in;
54	float out[3];	/* one answer per rounding mode except towardzero */
55} tests[] = {
56/* input	output (expected) */
57    { 0.0,	{ 0.0, 0.0, 0.0 }},
58    { 0.5,	{ 0.0, 0.0, 1.0 }},
59    { M_PI,	{ 3.0, 3.0, 4.0 }},
60    { 65536.5,	{ 65536, 65536, 65537 }},
61    { INFINITY,	{ INFINITY, INFINITY, INFINITY }},
62    { NAN,	{ NAN, NAN, NAN }},
63};
64
65static const int ntests = sizeof(tests) / sizeof(tests[0]);
66
67/*
68 * Compare d1 and d2 using special rules: NaN == NaN and +0 != -0.
69 * Fail an assertion if they differ.
70 */
71static int
72fpequal(long double d1, long double d2)
73{
74
75	if (d1 != d2)
76		return (isnan(d1) && isnan(d2));
77	return (copysignl(1.0, d1) == copysignl(1.0, d2));
78}
79
80/* Get the appropriate result for the current rounding mode. */
81static float
82get_output(int testindex, int rmodeindex, int negative)
83{
84	double out;
85
86	if (negative) {	/* swap downwards and upwards if input is negative */
87		if (rmodeindex == 1)
88			rmodeindex = 2;
89		else if (rmodeindex == 2)
90			rmodeindex = 1;
91	}
92	if (rmodeindex == 3) /* FE_TOWARDZERO uses the value for downwards */
93		rmodeindex = 1;
94	out = tests[testindex].out[rmodeindex];
95	return (negative ? -out : out);
96}
97
98static void
99test_nearby(int testindex)
100{
101	float in, out;
102	int i;
103
104	for (i = 0; i < sizeof(rmodes) / sizeof(rmodes[0]); i++) {
105		fesetround(rmodes[i]);
106		feclearexcept(ALL_STD_EXCEPT);
107
108		in = tests[testindex].in;
109		out = get_output(testindex, i, 0);
110		assert(fpequal(out, nearbyintf(in)));
111		assert(fpequal(out, nearbyint(in)));
112		assert(fpequal(out, nearbyintl(in)));
113		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
114
115		in = -tests[testindex].in;
116		out = get_output(testindex, i, 1);
117		assert(fpequal(out, nearbyintf(in)));
118		assert(fpequal(out, nearbyint(in)));
119		assert(fpequal(out, nearbyintl(in)));
120		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
121	}
122
123	printf("ok %d\t\t# nearbyint(+%g)\n", testnum++, in);
124}
125
126static void
127test_modf(int testindex)
128{
129	float in, out;
130	float ipartf, ipart_expected;
131	double ipart;
132	long double ipartl;
133	int i;
134
135	for (i = 0; i < sizeof(rmodes) / sizeof(rmodes[0]); i++) {
136		fesetround(rmodes[i]);
137		feclearexcept(ALL_STD_EXCEPT);
138
139		in = tests[testindex].in;
140		ipart_expected = tests[testindex].out[1];
141		out = copysignf(
142		    isinf(ipart_expected) ? 0.0 : in - ipart_expected, in);
143		ipartl = ipart = ipartf = 42.0;
144
145		assert(fpequal(out, modff(in, &ipartf)));
146		assert(fpequal(ipart_expected, ipartf));
147		assert(fpequal(out, modf(in, &ipart)));
148		assert(fpequal(ipart_expected, ipart));
149		assert(fpequal(out, modfl(in, &ipartl)));
150		assert(fpequal(ipart_expected, ipartl));
151		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
152
153		in = -in;
154		ipart_expected = -ipart_expected;
155		out = -out;
156		ipartl = ipart = ipartf = 42.0;
157		assert(fpequal(out, modff(in, &ipartf)));
158		assert(fpequal(ipart_expected, ipartf));
159		assert(fpequal(out, modf(in, &ipart)));
160		assert(fpequal(ipart_expected, ipart));
161		assert(fpequal(out, modfl(in, &ipartl)));
162		assert(fpequal(ipart_expected, ipartl));
163		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
164	}
165
166	printf("ok %d\t\t# modf(+%g)\n", testnum++, in);
167}
168
169int
170main(int argc, char *argv[])
171{
172	int i;
173
174	printf("1..%d\n", ntests * 2);
175	testnum = 1;
176	for (i = 0; i < ntests; i++) {
177		test_nearby(i);
178		test_modf(i);
179	}
180
181	return (0);
182}
183