1 /* $OpenBSD: logarithm_test.c,v 1.2 2021/12/13 16:56:48 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/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/types.h> 38 #include <fenv.h> 39 #include <float.h> 40 #include <math.h> 41 #include <stdio.h> 42 43 #ifdef __i386__ 44 #include <ieeefp.h> 45 #endif 46 47 #include "test-utils.h" 48 49 #pragma STDC FENV_ACCESS ON 50 51 /* 52 * Test that a function returns the correct value and sets the 53 * exception flags correctly. The exceptmask specifies which 54 * exceptions we should check. We need to be lenient for several 55 * reasoons, but mainly because on some architectures it's impossible 56 * to raise FE_OVERFLOW without raising FE_INEXACT. 57 * 58 * These are macros instead of functions so that assert provides more 59 * meaningful error messages. 60 * 61 * XXX The volatile here is to avoid gcc's bogus constant folding and work 62 * around the lack of support for the FENV_ACCESS pragma. 63 */ 64 #define test(func, x, result, exceptmask, excepts) do { \ 65 volatile long double _d = x; \ 66 ATF_CHECK_EQ(0, feclearexcept(FE_ALL_EXCEPT)); \ 67 CHECK_FPEQUAL((func)(_d), (result)); \ 68 CHECK_FP_EXCEPTIONS_MSG(excepts, exceptmask, "for %s(%s)", \ 69 #func, #x); \ 70 } while (0) 71 72 #define test_tol(func, z, result, tol) do { \ 73 volatile long double _d = z; \ 74 debug(" testing %6s(%15La) ~= % .36Le\n", #func, _d, result); \ 75 CHECK_FPEQUAL_TOL((func)(_d), (result), (tol), CS_BOTH); \ 76 } while (0) 77 78 /* Test all the functions that compute log(x). */ 79 #define testall0(x, result, exceptmask, excepts) do { \ 80 test(log, x, result, exceptmask, excepts); \ 81 test(logf, x, result, exceptmask, excepts); \ 82 test(logl, x, result, exceptmask, excepts); \ 83 test(log2, x, result, exceptmask, excepts); \ 84 test(log2f, x, result, exceptmask, excepts); \ 85 test(log2l, x, result, exceptmask, excepts); \ 86 test(log10, x, result, exceptmask, excepts); \ 87 test(log10f, x, result, exceptmask, excepts); \ 88 test(log10l, x, result, exceptmask, excepts); \ 89 } while (0) 90 91 /* Test all the functions that compute log(1+x). */ 92 #define testall1(x, result, exceptmask, excepts) do { \ 93 test(log1p, x, result, exceptmask, excepts); \ 94 test(log1pf, x, result, exceptmask, excepts); \ 95 test(log1pl, x, result, exceptmask, excepts); \ 96 } while (0) 97 98 ATF_TC_WITHOUT_HEAD(generic_tests); 99 ATF_TC_BODY(generic_tests, tc) 100 { 101 102 /* log(1) == 0, no exceptions raised */ 103 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0); 104 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0); 105 testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0); 106 107 /* log(NaN) == NaN, no exceptions raised */ 108 testall0(NAN, NAN, ALL_STD_EXCEPT, 0); 109 testall1(NAN, NAN, ALL_STD_EXCEPT, 0); 110 111 /* log(Inf) == Inf, no exceptions raised */ 112 testall0(INFINITY, INFINITY, ALL_STD_EXCEPT, 0); 113 testall1(INFINITY, INFINITY, ALL_STD_EXCEPT, 0); 114 115 /* log(x) == NaN for x < 0, invalid exception raised */ 116 testall0(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID); 117 testall1(-INFINITY, NAN, ALL_STD_EXCEPT, FE_INVALID); 118 testall0(-1.0, NAN, ALL_STD_EXCEPT, FE_INVALID); 119 testall1(-1.5, NAN, ALL_STD_EXCEPT, FE_INVALID); 120 121 /* log(0) == -Inf, divide-by-zero exception */ 122 testall0(0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO); 123 testall0(-0.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO); 124 testall1(-1.0, -INFINITY, ALL_STD_EXCEPT & ~FE_INEXACT, FE_DIVBYZERO); 125 } 126 127 ATF_TC_WITHOUT_HEAD(log2_tests); 128 ATF_TC_BODY(log2_tests, tc) 129 { 130 unsigned i; 131 132 /* 133 * We should insist that log2() return exactly the correct 134 * result and not raise an inexact exception for powers of 2. 135 */ 136 ATF_REQUIRE_EQ(0, feclearexcept(FE_ALL_EXCEPT)); 137 for (i = FLT_MIN_EXP - FLT_MANT_DIG; i < FLT_MAX_EXP; i++) { 138 ATF_CHECK_EQ(i, log2f(ldexpf(1.0, i))); 139 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT); 140 } 141 for (i = DBL_MIN_EXP - DBL_MANT_DIG; i < DBL_MAX_EXP; i++) { 142 ATF_CHECK_EQ(i, log2(ldexp(1.0, i))); 143 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT); 144 } 145 for (i = LDBL_MIN_EXP - LDBL_MANT_DIG; i < LDBL_MAX_EXP; i++) { 146 ATF_CHECK_EQ(i, log2l(ldexpl(1.0, i))); 147 CHECK_FP_EXCEPTIONS(0, ALL_STD_EXCEPT); 148 } 149 } 150 151 ATF_TC_WITHOUT_HEAD(roundingmode_tests); 152 ATF_TC_BODY(roundingmode_tests, tc) 153 { 154 155 /* 156 * Corner cases in other rounding modes. 157 */ 158 fesetround(FE_DOWNWARD); 159 /* These are still positive per IEEE 754R */ 160 #if 0 161 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0); 162 #else 163 /* logl, log2l, and log10l don't pass yet. */ 164 test(log, 1.0, 0.0, ALL_STD_EXCEPT, 0); 165 test(logf, 1.0, 0.0, ALL_STD_EXCEPT, 0); 166 test(log2, 1.0, 0.0, ALL_STD_EXCEPT, 0); 167 test(log2f, 1.0, 0.0, ALL_STD_EXCEPT, 0); 168 test(log10, 1.0, 0.0, ALL_STD_EXCEPT, 0); 169 test(log10f, 1.0, 0.0, ALL_STD_EXCEPT, 0); 170 #endif 171 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0); 172 fesetround(FE_TOWARDZERO); 173 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0); 174 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0); 175 176 fesetround(FE_UPWARD); 177 testall0(1.0, 0.0, ALL_STD_EXCEPT, 0); 178 testall1(0.0, 0.0, ALL_STD_EXCEPT, 0); 179 /* log1p(-0.0) == -0.0 even when rounding upwards */ 180 testall1(-0.0, -0.0, ALL_STD_EXCEPT, 0); 181 182 fesetround(FE_TONEAREST); 183 } 184 185 ATF_TC_WITHOUT_HEAD(accuracy_tests); 186 ATF_TC_BODY(accuracy_tests, tc) 187 { 188 static const struct { 189 float x; 190 long double log2x; 191 long double logex; 192 long double log10x; 193 } tests[] = { 194 { 0x1p-120 + 0x1p-140, 195 -1.19999998624139449158861798943319717e2L, 196 -8.31776607135195754708796206665656732e1L, 197 -3.61235990655024477716980559136055915e1L, 198 }, 199 { 1.0 - 0x1p-20, 200 -1.37586186296463416424364914705656460e-6L, 201 -9.53674771153890007250243736279163253e-7L, 202 -4.14175690642480911859354110516159131e-7L, }, 203 { 1.0 + 0x1p-20, 204 1.37586055084113820105668028340371476e-6L, 205 9.53673861659188233908415514963336144e-7L, 206 4.14175295653950611453333571759200697e-7L }, 207 { 19.75, 208 4.30378074817710292442728634194115348e0L, 209 2.98315349134713087533848129856505779e0L, 210 1.29556709996247903756734359702926363e0L }, 211 { 19.75 * 0x1p100, 212 1.043037807481771029244272863419411534e2L, 213 72.29787154734166181706169344438271459357255439172762452L, 214 3.139856666636059855894123306947856631e1L }, 215 }; 216 unsigned i; 217 218 long double log1p_ldbl_ulp = LDBL_ULP(); 219 #if LDBL_MANT_DIG > 64 220 /* 221 * On ld128 platforms the log1p() implementation provides less accuracy, 222 * but does still match the ld80 precision. Use the ld80 LDBL_ULP() 223 * value for now to avoid losing test coverage for the other functions. 224 * Reported as https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=253984 225 */ 226 log1p_ldbl_ulp = ldexpl(1.0, 1 - 64); 227 #endif 228 229 for (i = 0; i < nitems(tests); i++) { 230 test_tol(log2, tests[i].x, tests[i].log2x, DBL_ULP()); 231 test_tol(log2f, tests[i].x, tests[i].log2x, FLT_ULP()); 232 test_tol(log2l, tests[i].x, tests[i].log2x, LDBL_ULP()); 233 test_tol(log, tests[i].x, tests[i].logex, DBL_ULP()); 234 test_tol(logf, tests[i].x, tests[i].logex, FLT_ULP()); 235 test_tol(logl, tests[i].x, tests[i].logex, LDBL_ULP()); 236 test_tol(log10, tests[i].x, tests[i].log10x, DBL_ULP()); 237 test_tol(log10f, tests[i].x, tests[i].log10x, FLT_ULP()); 238 test_tol(log10l, tests[i].x, tests[i].log10x, LDBL_ULP()); 239 if (tests[i].x >= 0.5) { 240 test_tol(log1p, tests[i].x - 1, tests[i].logex, 241 DBL_ULP()); 242 test_tol(log1pf, tests[i].x - 1, tests[i].logex, 243 FLT_ULP()); 244 test_tol(log1pl, tests[i].x - 1, tests[i].logex, 245 log1p_ldbl_ulp); 246 } 247 } 248 } 249 250 ATF_TC_WITHOUT_HEAD(log1p_accuracy_tests); 251 ATF_TC_BODY(log1p_accuracy_tests, tc) 252 { 253 #if LDBL_MANT_DIG > 64 254 if (atf_tc_get_config_var_as_bool_wd(tc, "ci", false)) 255 atf_tc_expect_fail("https://bugs.freebsd.org/253984"); 256 #endif 257 258 test_tol(log1pf, 0x0.333333p0F, 259 1.82321546859847114303367992804596800640e-1L, FLT_ULP()); 260 test_tol(log1p, 0x0.3333333333333p0, 261 1.82321556793954589204283870982629267635e-1L, DBL_ULP()); 262 test_tol(log1pl, 0x0.33333333333333332p0L, 263 1.82321556793954626202683007050468762914e-1L, LDBL_ULP()); 264 265 test_tol(log1pf, -0x0.333333p0F, 266 -2.23143536413048672940940199918017467652e-1L, FLT_ULP()); 267 test_tol(log1p, -0x0.3333333333333p0, 268 -2.23143551314209700255143859052009022937e-1L, DBL_ULP()); 269 test_tol(log1pl, -0x0.33333333333333332p0L, 270 -2.23143551314209755752742563153765697950e-1L, LDBL_ULP()); 271 } 272 273 ATF_TP_ADD_TCS(tp) 274 { 275 276 ATF_TP_ADD_TC(tp, generic_tests); 277 ATF_TP_ADD_TC(tp, log2_tests); 278 ATF_TP_ADD_TC(tp, roundingmode_tests); 279 ATF_TP_ADD_TC(tp, accuracy_tests); 280 ATF_TP_ADD_TC(tp, log1p_accuracy_tests); 281 282 return (atf_no_error()); 283 } 284