1/*-
2 * Copyright (c) 2008 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 exp*().
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
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 b^x. */
70#define	testall0(x, result, exceptmask, excepts)	do {		\
71	test(exp, x, result, exceptmask, excepts);			\
72	test(expf, x, result, exceptmask, excepts);			\
73	test(exp2, x, result, exceptmask, excepts);			\
74	test(exp2f, x, result, exceptmask, excepts);			\
75	test(exp2l, x, result, exceptmask, excepts);			\
76} while (0)
77
78/* Test all the functions that compute b^x - 1. */
79#define	testall1(x, result, exceptmask, excepts)	do {		\
80	test(expm1, x, result, exceptmask, excepts);			\
81	test(expm1f, x, result, exceptmask, excepts);			\
82} while (0)
83
84/*
85 * Determine whether x and y are equal, with two special rules:
86 *	+0.0 != -0.0
87 *	 NaN == NaN
88 */
89int
90fpequal(long double x, long double y)
91{
92	return ((x == y && !signbit(x) == !signbit(y)) || isnan(x) && isnan(y));
93}
94
95void
96run_generic_tests(void)
97{
98
99	/* exp(0) == 1, no exceptions raised */
100	testall0(0.0, 1.0, ALL_STD_EXCEPT, 0);
101	testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
102	testall0(-0.0, 1.0, ALL_STD_EXCEPT, 0);
103	testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);
104
105	/* exp(NaN) == NaN, no exceptions raised */
106	testall0(NAN, NAN, ALL_STD_EXCEPT, 0);
107	testall1(NAN, NAN, ALL_STD_EXCEPT, 0);
108
109	/* exp(Inf) == Inf, no exceptions raised */
110	testall0(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
111	testall1(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
112
113	/* exp(-Inf) == 0, no exceptions raised */
114	testall0(-INFINITY, 0.0, ALL_STD_EXCEPT, 0);
115	testall1(-INFINITY, -1.0, ALL_STD_EXCEPT, 0);
116
117	/* exp(big) == Inf, overflow exception */
118	testall0(50000.0, INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_OVERFLOW);
119	testall1(50000.0, INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_OVERFLOW);
120
121	/* exp(small) == 0, underflow and inexact exceptions */
122	testall0(-50000.0, 0.0, ALL_STD_EXCEPT, FE_UNDERFLOW | FE_INEXACT);
123	testall1(-50000.0, -1.0, ALL_STD_EXCEPT, FE_INEXACT);
124}
125
126void
127run_exp2_tests(void)
128{
129	int i;
130
131	/*
132	 * We should insist that exp2() return exactly the correct
133	 * result and not raise an inexact exception for integer
134	 * arguments.
135	 */
136	feclearexcept(FE_ALL_EXCEPT);
137	for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) {
138		assert(exp2f(i) == ldexpf(1.0, i));
139		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
140	}
141	for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) {
142		assert(exp2(i) == ldexp(1.0, i));
143		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
144	}
145	for (i = LDBL_MIN_EXP - LDBL_MANT_DIG; i < LDBL_MAX_EXP; i++) {
146		assert(exp2l(i) == ldexpl(1.0, i));
147		assert(fetestexcept(ALL_STD_EXCEPT) == 0);
148	}
149}
150
151int
152main(int argc, char *argv[])
153{
154
155	printf("1..3\n");
156
157	run_generic_tests();
158	printf("ok 1 - exponential\n");
159
160#ifdef __i386__
161	fpsetprec(FP_PE);
162	run_generic_tests();
163#endif
164	printf("ok 2 - exponential\n");
165
166	run_exp2_tests();
167	printf("ok 3 - exponential\n");
168
169	return (0);
170}
171