t_fe_round.c revision 1.21
1 /* $NetBSD: t_fe_round.c,v 1.21 2025/04/17 13:45:22 riastradh Exp $ */ 2 3 /* 4 * Written by Maya Rashish <maya (at) NetBSD.org> 5 * Public domain. 6 * 7 * Testing IEEE-754 rounding modes (and lrint) 8 */ 9 10 #include <sys/cdefs.h> 11 __RCSID("$NetBSD: t_fe_round.c,v 1.21 2025/04/17 13:45:22 riastradh Exp $"); 12 13 #include <atf-c.h> 14 #include <fenv.h> 15 #include <math.h> 16 #include <stdint.h> 17 #include <stdio.h> 18 #include <stdlib.h> 19 20 #ifdef __HAVE_FENV 21 22 /*#pragma STDC FENV_ACCESS ON gcc?? */ 23 24 #define INT 9223L 25 26 static const char * 27 rmname(int rm) 28 { 29 switch (rm) { 30 case FE_TOWARDZERO: 31 return "FE_TOWARDZERO"; 32 case FE_DOWNWARD: 33 return "FE_DOWNWARD"; 34 case FE_UPWARD: 35 return "FE_UPWARD"; 36 case FE_TONEAREST: 37 return "FE_TONEAREST"; 38 default: 39 return "unknown"; 40 } 41 } 42 43 /* 44 * Examples are chosen to fit within the smallest single-precision 45 * format any NetBSD port uses, so that we can write the examples once 46 * in type double, and convert to single without raising inexact-result 47 * exceptions when we're trying to test whether the integer-rounding 48 * functions raise them. 49 */ 50 static const struct { 51 int round_mode; 52 double input; 53 long int expected; 54 } values[] = { 55 { FE_DOWNWARD, 3.75, 3}, 56 { FE_DOWNWARD, -3.75, -4}, 57 { FE_DOWNWARD, +0., 0}, 58 { FE_DOWNWARD, -0., 0}, 59 { FE_DOWNWARD, -INT-0.0625, -INT-1}, 60 { FE_DOWNWARD, +INT-0.0625, INT-1}, 61 { FE_DOWNWARD, -INT+0.0625, -INT}, 62 { FE_DOWNWARD, +INT+0.0625, INT}, 63 64 { FE_UPWARD, +0., 0}, 65 { FE_UPWARD, -0., 0}, 66 { FE_UPWARD, -123.75, -123}, 67 { FE_UPWARD, 123.75, 124}, 68 { FE_UPWARD, -INT-0.0625, -INT}, 69 { FE_UPWARD, +INT-0.0625, INT}, 70 { FE_UPWARD, -INT+0.0625, -INT+1}, 71 { FE_UPWARD, +INT+0.0625, INT+1}, 72 73 { FE_TOWARDZERO, 1.9375, 1}, 74 { FE_TOWARDZERO, -1.9375, -1}, 75 { FE_TOWARDZERO, 0.25, 0}, 76 { FE_TOWARDZERO, INT+0.0625, INT}, 77 { FE_TOWARDZERO, INT-0.0625, INT - 1}, 78 { FE_TOWARDZERO, -INT+0.0625, -INT + 1}, 79 { FE_TOWARDZERO, +0., 0}, 80 { FE_TOWARDZERO, -0., 0}, 81 82 { FE_TONEAREST, -INT-0.0625, -INT}, 83 { FE_TONEAREST, +INT-0.0625, INT}, 84 { FE_TONEAREST, -INT+0.0625, -INT}, 85 { FE_TONEAREST, +INT+0.0625, INT}, 86 { FE_TONEAREST, -INT-0.53125, -INT-1}, 87 { FE_TONEAREST, +INT-0.53125, INT-1}, 88 { FE_TONEAREST, -INT+0.53125, -INT+1}, 89 { FE_TONEAREST, +INT+0.53125, INT+1}, 90 { FE_TONEAREST, +0., 0}, 91 { FE_TONEAREST, -0., 0}, 92 }; 93 94 ATF_TC(fe_lrint); 95 ATF_TC_HEAD(fe_lrint, tc) 96 { 97 atf_tc_set_md_var(tc, "descr", 98 "Checking IEEE 754 rounding modes using lrint(3)"); 99 } 100 101 ATF_TC_BODY(fe_lrint, tc) 102 { 103 enum { 104 LLRINT, 105 LLRINTF, 106 LRINT, 107 LRINTF, 108 N_FN, 109 } fn; 110 static const char *const fnname[] = { 111 [LLRINT] = "llrint", 112 [LLRINTF] = "llrintf", 113 [LRINT] = "lrint", 114 [LRINTF] = "lrintf", 115 }; 116 long int received; 117 unsigned i; 118 119 for (i = 0; i < __arraycount(values); i++) { 120 for (fn = 0; fn < N_FN; fn++) { 121 /* 122 * Set the requested rounding mode. 123 */ 124 fesetround(values[i].round_mode); 125 126 /* 127 * Call the lrint(3)-family function. 128 */ 129 switch (fn) { 130 case LLRINT: 131 received = llrint(values[i].input); 132 break; 133 case LLRINTF: 134 received = llrintf(values[i].input); 135 break; 136 case LRINT: 137 received = lrint(values[i].input); 138 break; 139 case LRINTF: 140 received = lrintf(values[i].input); 141 break; 142 default: 143 atf_tc_fail("impossible"); 144 } 145 146 /* 147 * Assuming the result we got has zero 148 * fractional part, casting to long int should 149 * have no rounding. Verify it matches the 150 * integer we expect. 151 */ 152 ATF_CHECK_MSG((long int)received == values[i].expected, 153 "[%u] %s %s(%f): got %ld, expected %ld", 154 i, rmname(values[i].round_mode), fnname[fn], 155 values[i].input, 156 (long int)received, values[i].expected); 157 158 /* Do we get the same rounding mode out? */ 159 ATF_CHECK_MSG(fegetround() == values[i].round_mode, 160 "[%u] %s: set %d (%s), got %d (%s)", 161 i, fnname[fn], 162 values[i].round_mode, rmname(values[i].round_mode), 163 fegetround(), rmname(fegetround())); 164 } 165 } 166 } 167 168 ATF_TC(fe_nearbyint_rint); 169 ATF_TC_HEAD(fe_nearbyint_rint, tc) 170 { 171 atf_tc_set_md_var(tc, "descr", 172 "Checking IEEE 754 rounding modes using nearbyint/rint"); 173 } 174 175 ATF_TC_BODY(fe_nearbyint_rint, tc) 176 { 177 enum { 178 NEARBYINT, 179 NEARBYINTF, 180 NEARBYINTL, 181 RINT, 182 RINTF, 183 RINTL, 184 N_FN, 185 } fn; 186 static const char *const fnname[] = { 187 [NEARBYINT] = "nearbyint", 188 [NEARBYINTF] = "nearbyintf", 189 [NEARBYINTL] = "nearbyintl", 190 [RINT] = "rint", 191 [RINTF] = "rintf", 192 [RINTL] = "rintl", 193 }; 194 double received, ipart, fpart; 195 unsigned i; 196 197 #ifdef __sparc64__ 198 atf_tc_expect_fail("PR port-sparc64/59310:" 199 " t_fe_round:fe_nearbyint_rint tests are failing"); 200 #endif 201 202 for (i = 0; i < __arraycount(values); i++) { 203 for (fn = 0; fn < N_FN; fn++) { 204 bool expect_except = 205 values[i].input != (double)values[i].expected; 206 207 /* 208 * Set the requested rounding mode. 209 */ 210 fesetround(values[i].round_mode); 211 212 #ifdef __ia64__ 213 /* 214 * Without this barrier, we get: 215 * 216 * /tmp//ccJayu9g.s:2793: Warning: Use of 'mov.m' violates RAW dependency 'AR[FPSR].sf0.flags' (impliedf) 217 * /tmp//ccJayu9g.s:2793: Warning: Only the first path encountering the conflict is reported 218 * /tmp//ccJayu9g.s:2757: Warning: This is the location of the conflicting usage 219 * 220 * (If you fix this, remove the entry from doc/HACKS.) 221 */ 222 __insn_barrier(); 223 #endif 224 225 /* 226 * Clear sticky floating-point exception bits 227 * so we can verify whether the FE_INEXACT 228 * exception is raised. 229 */ 230 feclearexcept(FE_ALL_EXCEPT); 231 232 /* 233 * Call the rint(3)-family function. 234 */ 235 switch (fn) { 236 case NEARBYINT: 237 received = nearbyint(values[i].input); 238 expect_except = false; 239 break; 240 case NEARBYINTF: 241 received = nearbyintf(values[i].input); 242 expect_except = false; 243 break; 244 case NEARBYINTL: 245 received = nearbyintl(values[i].input); 246 expect_except = false; 247 break; 248 case RINT: 249 received = rint(values[i].input); 250 break; 251 case RINTF: 252 received = rintf(values[i].input); 253 break; 254 case RINTL: 255 received = rintl(values[i].input); 256 break; 257 default: 258 atf_tc_fail("impossible"); 259 } 260 261 /* 262 * Verify FE_INEXACT was raised or not, 263 * depending on whether there was rounding and 264 * whether the function is supposed to raise 265 * exceptions. 266 */ 267 if (expect_except) { 268 ATF_CHECK_MSG(fetestexcept(FE_INEXACT) != 0, 269 "[%u] %s %s(%f)" 270 " failed to raise FE_INEXACT", 271 i, rmname(values[i].round_mode), 272 fnname[fn], values[i].input); 273 } else { 274 ATF_CHECK_MSG(fetestexcept(FE_INEXACT) == 0, 275 "[%u] %s %s(%f)" 276 " spuriously raised FE_INEXACT", 277 i, rmname(values[i].round_mode), 278 fnname[fn], values[i].input); 279 } 280 281 /* 282 * Verify the fractional part of the result is 283 * zero -- the result of rounding to an integer 284 * is supposed to be an integer. 285 */ 286 fpart = modf(received, &ipart); 287 ATF_CHECK_MSG(fpart == 0, 288 "[%u] %s %s(%f)=%f has fractional part %f" 289 " (integer part %f)", 290 i, rmname(values[i].round_mode), fnname[fn], 291 values[i].input, received, fpart, ipart); 292 293 /* 294 * Assuming the result we got has zero 295 * fractional part, casting to long int should 296 * have no rounding. Verify it matches the 297 * integer we expect. 298 */ 299 ATF_CHECK_MSG((long int)received == values[i].expected, 300 "[%u] %s %s(%f): got %f, expected %ld", 301 i, rmname(values[i].round_mode), fnname[fn], 302 values[i].input, received, values[i].expected); 303 304 /* Do we get the same rounding mode out? */ 305 ATF_CHECK_MSG(fegetround() == values[i].round_mode, 306 "[%u] %s: set %d (%s), got %d (%s)", 307 i, fnname[fn], 308 values[i].round_mode, rmname(values[i].round_mode), 309 fegetround(), rmname(fegetround())); 310 } 311 } 312 } 313 314 #ifdef __HAVE_LONG_DOUBLE 315 316 /* 317 * Use one bit more than fits in IEEE 754 binary64. 318 */ 319 static const struct { 320 int round_mode; 321 long double input; 322 int64_t expected; 323 } valuesl[] = { 324 { FE_TOWARDZERO, 0x2.00000000000008p+52L, 0x20000000000000 }, 325 { FE_DOWNWARD, 0x2.00000000000008p+52L, 0x20000000000000 }, 326 { FE_UPWARD, 0x2.00000000000008p+52L, 0x20000000000001 }, 327 { FE_TONEAREST, 0x2.00000000000008p+52L, 0x20000000000000 }, 328 { FE_TOWARDZERO, 0x2.00000000000018p+52L, 0x20000000000001 }, 329 { FE_DOWNWARD, 0x2.00000000000018p+52L, 0x20000000000001 }, 330 { FE_UPWARD, 0x2.00000000000018p+52L, 0x20000000000002 }, 331 { FE_TONEAREST, 0x2.00000000000018p+52L, 0x20000000000002 }, 332 }; 333 334 ATF_TC(fe_nearbyintl_rintl); 335 ATF_TC_HEAD(fe_nearbyintl_rintl, tc) 336 { 337 atf_tc_set_md_var(tc, "descr", 338 "Checking IEEE 754 rounding modes using nearbyintl/rintl"); 339 } 340 341 ATF_TC_BODY(fe_nearbyintl_rintl, tc) 342 { 343 enum { 344 RINTL, 345 NEARBYINTL, 346 N_FN, 347 } fn; 348 static const char *const fnname[] = { 349 [RINTL] = "rintl", 350 [NEARBYINTL] = "nearbyintl", 351 }; 352 long double received, ipart, fpart; 353 unsigned i; 354 355 #ifdef __sparc64__ 356 atf_tc_expect_fail("PR port-sparc64/59310:" 357 " t_fe_round:fe_nearbyint_rint tests are failing"); 358 #endif 359 360 for (i = 0; i < __arraycount(valuesl); i++) { 361 for (fn = 0; fn < N_FN; fn++) { 362 bool expect_except = 363 (valuesl[i].input != 364 (long double)valuesl[i].expected); 365 366 /* 367 * Set the requested rounding mode. 368 */ 369 fesetround(valuesl[i].round_mode); 370 371 /* 372 * Clear sticky floating-point exception bits 373 * so we can verify whether the FE_INEXACT 374 * exception is raised. 375 */ 376 feclearexcept(FE_ALL_EXCEPT); 377 378 /* 379 * Call the rint(3)-family function. 380 */ 381 switch (fn) { 382 case NEARBYINTL: 383 received = nearbyintl(valuesl[i].input); 384 expect_except = false; 385 break; 386 case RINTL: 387 received = rintl(valuesl[i].input); 388 break; 389 default: 390 atf_tc_fail("impossible"); 391 } 392 393 /* 394 * Verify FE_INEXACT was raised or not, 395 * depending on whether there was rounding and 396 * whether the function is supposed to raise 397 * exceptions. 398 */ 399 if (expect_except) { 400 ATF_CHECK_MSG(fetestexcept(FE_INEXACT) != 0, 401 "[%u] %s %s(%Lf)" 402 " failed to raise FE_INEXACT", 403 i, rmname(valuesl[i].round_mode), 404 fnname[fn], valuesl[i].input); 405 } else { 406 ATF_CHECK_MSG(fetestexcept(FE_INEXACT) == 0, 407 "[%u] %s %s(%Lf)" 408 " spuriously raised FE_INEXACT", 409 i, rmname(valuesl[i].round_mode), 410 fnname[fn], valuesl[i].input); 411 } 412 413 /* 414 * Verify the fractional part of the result is 415 * zero -- the result of rounding to an integer 416 * is supposed to be an integer. 417 */ 418 fpart = modfl(received, &ipart); 419 ATF_CHECK_MSG(fpart == 0, 420 "[%u] %s %s(%Lf)=%Lf has fractional part %Lf" 421 " (integer part %Lf)", 422 i, rmname(valuesl[i].round_mode), fnname[fn], 423 valuesl[i].input, received, fpart, ipart); 424 425 /* 426 * Assuming the result we got has zero 427 * fractional part, casting to int64_t should 428 * have no rounding. Verify it matches the 429 * integer we expect. 430 */ 431 ATF_CHECK_MSG(((int64_t)received == 432 valuesl[i].expected), 433 "[%u] %s %s(%Lf): got %Lf, expected %jd", 434 i, rmname(valuesl[i].round_mode), fnname[fn], 435 valuesl[i].input, received, valuesl[i].expected); 436 437 /* Do we get the same rounding mode out? */ 438 ATF_CHECK_MSG(fegetround() == valuesl[i].round_mode, 439 "[%u] %s: set %d (%s), got %d (%s)", 440 i, fnname[fn], 441 valuesl[i].round_mode, 442 rmname(valuesl[i].round_mode), 443 fegetround(), rmname(fegetround())); 444 } 445 } 446 } 447 448 #endif /* __HAVE_LONG_DOUBLE */ 449 450 ATF_TP_ADD_TCS(tp) 451 { 452 453 ATF_TP_ADD_TC(tp, fe_lrint); 454 ATF_TP_ADD_TC(tp, fe_nearbyint_rint); 455 #ifdef __HAVE_LONG_DOUBLE 456 ATF_TP_ADD_TC(tp, fe_nearbyintl_rintl); 457 #endif 458 459 return atf_no_error(); 460 } 461 462 #else /* !__HAVE_FENV */ 463 464 ATF_TP_ADD_TCS(tp) 465 { 466 467 /* 468 * No fenv, no fesetround to test. 469 */ 470 return atf_no_error(); 471 } 472 473 #endif /* __HAVE_FENV */ 474
Indexes created Thu Sep 25 16:09:42 GMT 2025