rem_test.c revision 165856 
1/*-
2 * Copyright (c) 2005 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 * Test for remainder functions: remainder, remainderf, remquo, remquof.
29 * Missing tests: fmod, fmodf.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/tools/regression/lib/msun/test-rem.c 165856 2007-01-07 09:25:22Z das $");
34
35#include <assert.h>
36#include <math.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <strings.h>
40
41static void test_invalid(double, double);
42static void testd(double, double, double, int);
43static void testf(float, float, float, int);
44
45#define	test(x, y, e_r, e_q) do {	\
46	testd(x, y, e_r, e_q);		\
47	testf(x, y, e_r, e_q);		\
48} while (0)
49
50int
51main(int argc, char *argv[])
52{
53
54	printf("1..2\n");
55
56	test_invalid(0.0, 0.0);
57	test_invalid(1.0, 0.0);
58	test_invalid(INFINITY, 0.0);
59	test_invalid(INFINITY, 1.0);
60	test_invalid(-INFINITY, 1.0);
61	test_invalid(NAN, 1.0);
62	test_invalid(1.0, NAN);
63
64	test(4, 4, 0, 1);
65	test(0, 3.0, 0, 0);
66	testd(0x1p-1074, 1, 0x1p-1074, 0x1p-1074);
67	testf(0x1p-149, 1, 0x1p-149, 0x1p-149);
68	test(3.0, 4, -1, 1);
69	test(3.0, -4, -1, -1);
70	testd(275 * 1193040, 275, 0, 1193040);
71	test(4.5 * 7.5, 4.5, -2.25, 8);	/* we should get the even one */
72	testf(0x1.9044f6p-1, 0x1.ce662ep-1, -0x1.f109cp-4, 1);
73
74	printf("ok 1 - rem\n");
75
76	/*
77	 * The actual quotient here is 864062210.50000003..., but
78	 * double-precision division gets -8.64062210.5, which rounds
79	 * the wrong way.  This test ensures that remquo() is smart
80	 * enough to get the low-order bit right.
81	 */
82	testd(-0x1.98260f22fc6dep-302, 0x1.fb3167c430a13p-332,
83	    0x1.fb3165b82de72p-333, -864062211);
84	/* Even harder cases with greater exponent separation */
85	test(0x1.fp100, 0x1.ep-40, -0x1.cp-41, 143165577);
86	testd(-0x1.abcdefp120, 0x1.87654321p-120,
87	    -0x1.69c78ec4p-121, -63816414);
88
89	printf("ok 2 - rem\n");
90
91	return (0);
92}
93
94static void
95test_invalid(double x, double y)
96{
97	int q;
98
99	q = 0xdeadbeef;
100
101	assert(isnan(remainder(x, y)));
102	assert(isnan(remquo(x, y, &q)));
103#ifdef STRICT
104	assert(q == 0xdeadbeef);
105#endif
106
107	assert(isnan(remainderf(x, y)));
108	assert(isnan(remquof(x, y, &q)));
109#ifdef STRICT
110	assert(q == 0xdeadbeef);
111#endif
112}
113
114/* 0x012345 ==> 0x01ffff */
115static inline int
116mask(int x)
117{
118	return ((unsigned)~0 >> (32 - fls(x)));
119}
120
121static void
122testd(double x, double y, double expected_rem, int expected_quo)
123{
124	int q;
125
126	q = random();
127	assert(remainder(x, y) == expected_rem);
128	assert(remquo(x, y, &q) == expected_rem);
129	assert((q & 0x7) == (expected_quo & 0x7));
130	if (q != 0) {
131		assert((q > 0) ^ !(expected_quo > 0));
132		q = abs(q);
133		assert(q == (abs(expected_quo) & mask(q)));
134	}
135}
136
137static void
138testf(float x, float y, float expected_rem, int expected_quo)
139{
140	int q;
141
142	q = random();
143	assert(remainderf(x, y) == expected_rem);
144	assert(remquof(x, y, &q) == expected_rem);
145	assert((q & 0x7) == (expected_quo & 0x7));
146	if (q != 0) {
147		assert((q > 0) ^ !(expected_quo > 0));
148		q = abs(q);
149		assert((q & mask(q)) == (abs(expected_quo) & mask(q)));
150	}
151}
152