logarithm_test.c revision 216214 
1/*-
2 * Copyright (c) 2008-2010 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 corner cases in log*().
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: head/tools/regression/lib/msun/test-logarithm.c 216214 2010-12-05 22:18:35Z das $");
33
34#include <assert.h>
35#include <fenv.h>
36#include <float.h>
37#include <math.h>
38#include <stdio.h>
39
40#ifdef __i386__
41#include <ieeefp.h>
42#endif
43
44#define	ALL_STD_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
45			 FE_OVERFLOW | FE_UNDERFLOW)
46
47#pragma STDC FENV_ACCESS ON
48
49/*
50 * Test that a function returns the correct value and sets the
51 * exception flags correctly. The exceptmask specifies which
52 * exceptions we should check. We need to be lenient for several
53 * reasoons, but mainly because on some architectures it's impossible
54 * to raise FE_OVERFLOW without raising FE_INEXACT.
55 *
56 * These are macros instead of functions so that assert provides more
57 * meaningful error messages.
58 *
59 * XXX The volatile here is to avoid gcc's bogus constant folding and work
60 *     around the lack of support for the FENV_ACCESS pragma.
61 */
62#define	test(func, x, result, exceptmask, excepts)	do {		\
63	volatile long double _d = x;					\
64	assert(feclearexcept(FE_ALL_EXCEPT) == 0);			\
65	assert(fpequal((func)(_d), (result)));				 \
66	assert(((func), fetestexcept(exceptmask) == (excepts)));	\
67} while (0)
68
69/* Test all the functions that compute log(x). */
70#define	testall0(x, result, exceptmask, excepts)	do {		\
71	test(log, x, result, exceptmask, excepts);			\
72	test(logf, x, result, exceptmask, excepts);			\
73	test(log2, x, result, exceptmask, excepts);			\
74	test(log2f, x, result, exceptmask, excepts);			\
75	test(log10, x, result, exceptmask, excepts);			\
76	test(log10f, x, result, exceptmask, excepts);			\
77} while (0)
78
79/* Test all the functions that compute log(1+x). */
80#define	testall1(x, result, exceptmask, excepts)	do {		\
81	test(log1p, x, result, exceptmask, excepts);			\
82	test(log1pf, x, result, exceptmask, excepts);			\
83} while (0)
84
85/*
86 * Determine whether x and y are equal, with two special rules:
87 *	+0.0 != -0.0
88 *	 NaN == NaN
89 */
90int
91fpequal(long double x, long double y)
92{
93	return ((x == y && signbit(x) == signbit(y)) || isnan(x) && isnan(y));
94}
95
96void
97run_generic_tests(void)
98{
99
100	/* exp(1) == 0, no exceptions raised */
101	testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
102	testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
103	testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);
104
105	/* log(NaN) == NaN, no exceptions raised */
106	testall0(NAN, NAN, ALL_STD_EXCEPT, 0);
107	testall1(NAN, NAN, ALL_STD_EXCEPT, 0);
108
109	/* log(Inf) == Inf, no exceptions raised */
110	testall0(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
111	testall1(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
112
113	/* log(x) == NaN for x < 0, invalid exception raised */
114	testall0(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
115	testall1(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
116	testall0(-1.0, NAN, ALL_STD_EXCEPT, FE_INVALID);
117	testall1(-1.5, NAN, ALL_STD_EXCEPT, FE_INVALID);
118
119	/* log(0) == -Inf, divide-by-zero exception */
120	testall0(0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
121	testall0(-0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
122	testall1(-1.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
123}
124
125void
126run_log2_tests(void)
127{
128	int i;
129
130	/*
131	 * We should insist that log2() return exactly the correct
132	 * result and not raise an inexact exception for powers of 2.
133	 */
134	feclearexcept(FE_ALL_EXCEPT);
135	for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) {
136		assert(log2f(ldexpf(1.0, i)) == i);
137		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
138	}
139	for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) {
140		assert(log2(ldexp(1.0, i)) == i);
141		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
142	}
143}
144
145int
146main(int argc, char *argv[])
147{
148
149	printf("1..2\n");
150
151	run_generic_tests();
152	printf("ok 1 - logarithm\n");
153
154	run_log2_tests();
155	printf("ok 2 - logarithm\n");
156
157	return (0);
158}
159