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 95ATF_TC_WITHOUT_HEAD(generic_tests); 96ATF_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 124ATF_TC_WITHOUT_HEAD(log2_tests); 125ATF_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 148ATF_TC_WITHOUT_HEAD(roundingmode_tests); 149ATF_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 182ATF_TC_WITHOUT_HEAD(accuracy_tests); 183ATF_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 247ATF_TC_WITHOUT_HEAD(log1p_accuracy_tests); 248ATF_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 270ATF_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