1 /* $OpenBSD: logarithm_test.c,v 1.3 2021/12/13 18:04:28 deraadt Exp $ */
2 /*-
3 * Copyright (c) 2008-2010 David Schultz <das@FreeBSD.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include "macros.h"
29
30 /*
31 * Tests for corner cases in log*().
32 */
33
34 #include <sys/types.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 #include "test-utils.h"
45
46 #pragma STDC FENV_ACCESS ON
47
48 /*
49 * Test that a function returns the correct value and sets the
50 * exception flags correctly. The exceptmask specifies which
51 * exceptions we should check. We need to be lenient for several
52 * reasoons, but mainly because on some architectures it's impossible
53 * to raise FE_OVERFLOW without raising FE_INEXACT.
54 *
55 * These are macros instead of functions so that assert provides more
56 * meaningful error messages.
57 *
58 * XXX The volatile here is to avoid gcc's bogus constant folding and work
59 * around the lack of support for the FENV_ACCESS pragma.
60 */
61 #define test(func, x, result, exceptmask, excepts) do { \
62 volatile long double _d = x; \
63 ATF_CHECK_EQ(0, feclearexcept(FE_ALL_EXCEPT)); \
64 CHECK_FPEQUAL((func)(_d), (result)); \
65 CHECK_FP_EXCEPTIONS_MSG(excepts, exceptmask, "for %s(%s)", \
66 #func, #x); \
67 } while (0)
68
69 #define test_tol(func, z, result, tol) do { \
70 volatile long double _d = z; \
71 debug(" testing %6s(%15La) ~= % .36Le\n", #func, _d, result); \
72 CHECK_FPEQUAL_TOL((func)(_d), (result), (tol), CS_BOTH); \
73 } while (0)
74
75 /* Test all the functions that compute log(x). */
76 #define testall0(x, result, exceptmask, excepts) do { \
77 test(log, x, result, exceptmask, excepts); \
78 test(logf, x, result, exceptmask, excepts); \
79 test(logl, x, result, exceptmask, excepts); \
80 test(log2, x, result, exceptmask, excepts); \
81 test(log2f, x, result, exceptmask, excepts); \
82 test(log2l, x, result, exceptmask, excepts); \
83 test(log10, x, result, exceptmask, excepts); \
84 test(log10f, x, result, exceptmask, excepts); \
85 test(log10l, x, result, exceptmask, excepts); \
86 } while (0)
87
88 /* Test all the functions that compute log(1+x). */
89 #define testall1(x, result, exceptmask, excepts) do { \
90 test(log1p, x, result, exceptmask, excepts); \
91 test(log1pf, x, result, exceptmask, excepts); \
92 test(log1pl, x, result, exceptmask, excepts); \
93 } while (0)
94
95 ATF_TC_WITHOUT_HEAD(generic_tests);
ATF_TC_BODY(generic_tests,tc)96 ATF_TC_BODY(generic_tests, tc)
97 {
98
99 /* log(1) == 0, no exceptions raised */
100 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
101 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
102 testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);
103
104 /* log(NaN) == NaN, no exceptions raised */
105 testall0(NAN, NAN, ALL_STD_EXCEPT, 0);
106 testall1(NAN, NAN, ALL_STD_EXCEPT, 0);
107
108 /* log(Inf) == Inf, no exceptions raised */
109 testall0(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
110 testall1(INFINITY, INFINITY, ALL_STD_EXCEPT, 0);
111
112 /* log(x) == NaN for x < 0, invalid exception raised */
113 testall0(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
114 testall1(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID);
115 testall0(-1.0, NAN, ALL_STD_EXCEPT, FE_INVALID);
116 testall1(-1.5, NAN, ALL_STD_EXCEPT, FE_INVALID);
117
118 /* log(0) == -Inf, divide-by-zero exception */
119 testall0(0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
120 testall0(-0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
121 testall1(-1.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO);
122 }
123
124 ATF_TC_WITHOUT_HEAD(log2_tests);
ATF_TC_BODY(log2_tests,tc)125 ATF_TC_BODY(log2_tests, tc)
126 {
127 unsigned i;
128
129 /*
130 * We should insist that log2() return exactly the correct
131 * result and not raise an inexact exception for powers of 2.
132 */
133 ATF_REQUIRE_EQ(0, feclearexcept(FE_ALL_EXCEPT));
134 for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) {
135 ATF_CHECK_EQ(i, log2f(ldexpf(1.0, i)));
136 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
137 }
138 for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) {
139 ATF_CHECK_EQ(i, log2(ldexp(1.0, i)));
140 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
141 }
142 for (i = LDBL_MIN_EXP - LDBL_MANT_DIG; i < LDBL_MAX_EXP; i++) {
143 ATF_CHECK_EQ(i, log2l(ldexpl(1.0, i)));
144 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT);
145 }
146 }
147
148 ATF_TC_WITHOUT_HEAD(roundingmode_tests);
ATF_TC_BODY(roundingmode_tests,tc)149 ATF_TC_BODY(roundingmode_tests, tc)
150 {
151
152 /*
153 * Corner cases in other rounding modes.
154 */
155 fesetround(FE_DOWNWARD);
156 /* These are still positive per IEEE 754R */
157 #if 0
158 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
159 #else
160 /* logl, log2l, and log10l don't pass yet. */
161 test(log, 1.0, 0.0, ALL_STD_EXCEPT, 0);
162 test(logf, 1.0, 0.0, ALL_STD_EXCEPT, 0);
163 test(log2, 1.0, 0.0, ALL_STD_EXCEPT, 0);
164 test(log2f, 1.0, 0.0, ALL_STD_EXCEPT, 0);
165 test(log10, 1.0, 0.0, ALL_STD_EXCEPT, 0);
166 test(log10f, 1.0, 0.0, ALL_STD_EXCEPT, 0);
167 #endif
168 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
169 fesetround(FE_TOWARDZERO);
170 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
171 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
172
173 fesetround(FE_UPWARD);
174 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0);
175 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0);
176 /* log1p(-0.0) == -0.0 even when rounding upwards */
177 testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0);
178
179 fesetround(FE_TONEAREST);
180 }
181
182 ATF_TC_WITHOUT_HEAD(accuracy_tests);
ATF_TC_BODY(accuracy_tests,tc)183 ATF_TC_BODY(accuracy_tests, tc)
184 {
185 static const struct {
186 float x;
187 long double log2x;
188 long double logex;
189 long double log10x;
190 } tests[] = {
191 { 0x1p-120 + 0x1p-140,
192 -1.19999998624139449158861798943319717e2L,
193 -8.31776607135195754708796206665656732e1L,
194 -3.61235990655024477716980559136055915e1L,
195 },
196 { 1.0 - 0x1p-20,
197 -1.37586186296463416424364914705656460e-6L,
198 -9.53674771153890007250243736279163253e-7L,
199 -4.14175690642480911859354110516159131e-7L, },
200 { 1.0 + 0x1p-20,
201 1.37586055084113820105668028340371476e-6L,
202 9.53673861659188233908415514963336144e-7L,
203 4.14175295653950611453333571759200697e-7L },
204 { 19.75,
205 4.30378074817710292442728634194115348e0L,
206 2.98315349134713087533848129856505779e0L,
207 1.29556709996247903756734359702926363e0L },
208 { 19.75 * 0x1p100,
209 1.043037807481771029244272863419411534e2L,
210 72.29787154734166181706169344438271459357255439172762452L,
211 3.139856666636059855894123306947856631e1L },
212 };
213 unsigned i;
214
215 long double log1p_ldbl_ulp = LDBL_ULP();
216 #if LDBL_MANT_DIG > 64
217 /*
218 * On ld128 platforms the log1p() implementation provides less accuracy,
219 * but does still match the ld80 precision. Use the ld80 LDBL_ULP()
220 * value for now to avoid losing test coverage for the other functions.
221 * Reported as https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253984
222 */
223 log1p_ldbl_ulp = ldexpl(1.0, 1 - 64);
224 #endif
225
226 for (i = 0; i < nitems(tests); i++) {
227 test_tol(log2, tests[i].x, tests[i].log2x, DBL_ULP());
228 test_tol(log2f, tests[i].x, tests[i].log2x, FLT_ULP());
229 test_tol(log2l, tests[i].x, tests[i].log2x, LDBL_ULP());
230 test_tol(log, tests[i].x, tests[i].logex, DBL_ULP());
231 test_tol(logf, tests[i].x, tests[i].logex, FLT_ULP());
232 test_tol(logl, tests[i].x, tests[i].logex, LDBL_ULP());
233 test_tol(log10, tests[i].x, tests[i].log10x, DBL_ULP());
234 test_tol(log10f, tests[i].x, tests[i].log10x, FLT_ULP());
235 test_tol(log10l, tests[i].x, tests[i].log10x, LDBL_ULP());
236 if (tests[i].x >= 0.5) {
237 test_tol(log1p, tests[i].x - 1, tests[i].logex,
238 DBL_ULP());
239 test_tol(log1pf, tests[i].x - 1, tests[i].logex,
240 FLT_ULP());
241 test_tol(log1pl, tests[i].x - 1, tests[i].logex,
242 log1p_ldbl_ulp);
243 }
244 }
245 }
246
247 ATF_TC_WITHOUT_HEAD(log1p_accuracy_tests);
ATF_TC_BODY(log1p_accuracy_tests,tc)248 ATF_TC_BODY(log1p_accuracy_tests, tc)
249 {
250 #if LDBL_MANT_DIG > 64
251 if (atf_tc_get_config_var_as_bool_wd(tc, "ci", false))
252 atf_tc_expect_fail("https://bugs.freebsd.org/253984");
253 #endif
254
255 test_tol(log1pf, 0x0.333333p0F,
256 1.82321546859847114303367992804596800640e-1L, FLT_ULP());
257 test_tol(log1p, 0x0.3333333333333p0,
258 1.82321556793954589204283870982629267635e-1L, DBL_ULP());
259 test_tol(log1pl, 0x0.33333333333333332p0L,
260 1.82321556793954626202683007050468762914e-1L, LDBL_ULP());
261
262 test_tol(log1pf, -0x0.333333p0F,
263 -2.23143536413048672940940199918017467652e-1L, FLT_ULP());
264 test_tol(log1p, -0x0.3333333333333p0,
265 -2.23143551314209700255143859052009022937e-1L, DBL_ULP());
266 test_tol(log1pl, -0x0.33333333333333332p0L,
267 -2.23143551314209755752742563153765697950e-1L, LDBL_ULP());
268 }
269
ATF_TP_ADD_TCS(tp)270 ATF_TP_ADD_TCS(tp)
271 {
272
273 ATF_TP_ADD_TC(tp, generic_tests);
274 ATF_TP_ADD_TC(tp, log2_tests);
275 ATF_TP_ADD_TC(tp, roundingmode_tests);
276 ATF_TP_ADD_TC(tp, accuracy_tests);
277 ATF_TP_ADD_TC(tp, log1p_accuracy_tests);
278
279 return (atf_no_error());
280 }
281