1 /* $OpenBSD: fenv.c,v 1.1 2011/03/21 21:51:28 martynas Exp $ */ 2 3 /*- 4 * Copyright (c) 2004 David Schultz <das@FreeBSD.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * Test the correctness and C99-compliance of various fenv.h features. 31 */ 32 33 #include <sys/cdefs.h> 34 #include <sys/types.h> 35 #include <sys/wait.h> 36 #include <assert.h> 37 #include <err.h> 38 #include <fenv.h> 39 #include <float.h> 40 #include <math.h> 41 #include <signal.h> 42 #include <stdio.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 /* 47 * Implementations are permitted to define additional exception flags 48 * not specified in the standard, so it is not necessarily true that 49 * FE_ALL_EXCEPT == ALL_STD_EXCEPT. 50 */ 51 #define ALL_STD_EXCEPT (FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \ 52 FE_OVERFLOW | FE_UNDERFLOW) 53 54 #define NEXCEPTS (sizeof(std_excepts) / sizeof(std_excepts[0])) 55 56 static const int std_excepts[] = { 57 FE_INVALID, 58 FE_DIVBYZERO, 59 FE_OVERFLOW, 60 FE_UNDERFLOW, 61 FE_INEXACT, 62 }; 63 64 /* init_exceptsets() initializes this to the power set of std_excepts[] */ 65 static int std_except_sets[1 << NEXCEPTS]; 66 67 static void init_exceptsets(void); 68 69 static void test_dfl_env(void); 70 static void test_fegsetenv(void); 71 static void test_fegsetexceptflag(void); 72 static void test_masking(void); 73 static void test_fegsetround(void); 74 static void test_feholdupdate(void); 75 static void test_feraiseexcept(void); 76 static void test_fetestclearexcept(void); 77 78 static int getround(void); 79 static void raiseexcept(int excepts); 80 static void trap_handler(int sig); 81 82 #pragma STDC FENV_ACCESS ON 83 84 int 85 main(int argc, char *argv[]) 86 { 87 88 printf("1..8\n"); 89 init_exceptsets(); 90 test_dfl_env(); 91 printf("ok 1 - fenv\n"); 92 test_fetestclearexcept(); 93 printf("ok 2 - fenv\n"); 94 test_fegsetexceptflag(); 95 printf("ok 3 - fenv\n"); 96 test_feraiseexcept(); 97 printf("ok 4 - fenv\n"); 98 test_fegsetround(); 99 printf("ok 5 - fenv\n"); 100 test_fegsetenv(); 101 printf("ok 6 - fenv\n"); 102 test_masking(); 103 printf("ok 7 - fenv\n"); 104 test_feholdupdate(); 105 printf("ok 8 - fenv\n"); 106 107 return (0); 108 } 109 110 /* 111 * Initialize std_except_sets[] to the power set of std_excepts[] 112 */ 113 void 114 init_exceptsets(void) 115 { 116 int i, j, sr; 117 118 for (i = 0; i < 1 << NEXCEPTS; i++) { 119 for (sr = i, j = 0; sr != 0; sr >>= 1, j++) 120 std_except_sets[i] |= std_excepts[j] & ((~sr & 1) - 1); 121 } 122 } 123 124 /* 125 * This tests checks the default FP environment, so it must be first. 126 * The memcmp() test below may be too much to ask for, since there 127 * could be multiple machine-specific default environments. 128 */ 129 static void 130 test_dfl_env(void) 131 { 132 #ifndef NO_STRICT_DFL_ENV 133 fenv_t env; 134 135 fegetenv(&env); 136 assert(memcmp(&env, FE_DFL_ENV, sizeof(env)) == 0); 137 #endif 138 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 139 } 140 141 /* 142 * Test fetestexcept() and feclearexcept(). 143 */ 144 static void 145 test_fetestclearexcept(void) 146 { 147 int excepts, i; 148 149 for (i = 0; i < 1 << NEXCEPTS; i++) 150 assert(fetestexcept(std_except_sets[i]) == 0); 151 for (i = 0; i < 1 << NEXCEPTS; i++) { 152 excepts = std_except_sets[i]; 153 154 /* FE_ALL_EXCEPT might be special-cased, as on i386. */ 155 raiseexcept(excepts); 156 assert(fetestexcept(excepts) == excepts); 157 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 158 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 159 160 raiseexcept(excepts); 161 assert(fetestexcept(excepts) == excepts); 162 if ((excepts & (FE_UNDERFLOW | FE_OVERFLOW)) != 0) { 163 excepts |= FE_INEXACT; 164 assert((fetestexcept(ALL_STD_EXCEPT) | FE_INEXACT) == 165 excepts); 166 } else { 167 assert(fetestexcept(ALL_STD_EXCEPT) == excepts); 168 } 169 assert(feclearexcept(excepts) == 0); 170 assert(fetestexcept(ALL_STD_EXCEPT) == 0); 171 } 172 } 173 174 /* 175 * Test fegetexceptflag() and fesetexceptflag(). 176 * 177 * Prerequisites: fetestexcept(), feclearexcept() 178 */ 179 static void 180 test_fegsetexceptflag(void) 181 { 182 fexcept_t flag; 183 int excepts, i; 184 185 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 186 for (i = 0; i < 1 << NEXCEPTS; i++) { 187 excepts = std_except_sets[i]; 188 189 assert(fegetexceptflag(&flag, excepts) == 0); 190 raiseexcept(ALL_STD_EXCEPT); 191 assert(fesetexceptflag(&flag, excepts) == 0); 192 assert(fetestexcept(ALL_STD_EXCEPT) == 193 (ALL_STD_EXCEPT ^ excepts)); 194 195 assert(fegetexceptflag(&flag, FE_ALL_EXCEPT) == 0); 196 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 197 assert(fesetexceptflag(&flag, excepts) == 0); 198 assert(fetestexcept(ALL_STD_EXCEPT) == 0); 199 assert(fesetexceptflag(&flag, ALL_STD_EXCEPT ^ excepts) == 0); 200 assert(fetestexcept(ALL_STD_EXCEPT) == 201 (ALL_STD_EXCEPT ^ excepts)); 202 203 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 204 } 205 } 206 207 /* 208 * Test feraiseexcept(). 209 * 210 * Prerequisites: fetestexcept(), feclearexcept() 211 */ 212 static void 213 test_feraiseexcept(void) 214 { 215 int excepts, i; 216 217 for (i = 0; i < 1 << NEXCEPTS; i++) { 218 excepts = std_except_sets[i]; 219 220 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 221 assert(feraiseexcept(excepts) == 0); 222 if ((excepts & (FE_UNDERFLOW | FE_OVERFLOW)) != 0) { 223 excepts |= FE_INEXACT; 224 assert((fetestexcept(ALL_STD_EXCEPT) | FE_INEXACT) == 225 excepts); 226 } else { 227 assert(fetestexcept(ALL_STD_EXCEPT) == excepts); 228 } 229 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 230 } 231 assert(feraiseexcept(FE_INVALID | FE_DIVBYZERO) == 0); 232 assert(fetestexcept(ALL_STD_EXCEPT) == (FE_INVALID | FE_DIVBYZERO)); 233 assert(feraiseexcept(FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT) == 0); 234 assert(fetestexcept(ALL_STD_EXCEPT) == ALL_STD_EXCEPT); 235 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 236 } 237 238 /* 239 * Test fegetround() and fesetround(). 240 */ 241 static void 242 test_fegsetround(void) 243 { 244 245 assert(fegetround() == FE_TONEAREST); 246 assert(getround() == FE_TONEAREST); 247 assert(FLT_ROUNDS == 1); 248 249 assert(fesetround(FE_DOWNWARD) == 0); 250 assert(fegetround() == FE_DOWNWARD); 251 assert(getround() == FE_DOWNWARD); 252 assert(FLT_ROUNDS == 3); 253 254 assert(fesetround(FE_UPWARD) == 0); 255 assert(getround() == FE_UPWARD); 256 assert(fegetround() == FE_UPWARD); 257 assert(FLT_ROUNDS == 2); 258 259 assert(fesetround(FE_TOWARDZERO) == 0); 260 assert(getround() == FE_TOWARDZERO); 261 assert(fegetround() == FE_TOWARDZERO); 262 assert(FLT_ROUNDS == 0); 263 264 assert(fesetround(FE_TONEAREST) == 0); 265 assert(getround() == FE_TONEAREST); 266 assert(FLT_ROUNDS == 1); 267 268 assert(feclearexcept(FE_ALL_EXCEPT) == 0); 269 } 270 271 /* 272 * Test fegetenv() and fesetenv(). 273 * 274 * Prerequisites: fetestexcept(), feclearexcept(), fegetround(), fesetround() 275 */ 276 static void 277 test_fegsetenv(void) 278 { 279 fenv_t env1, env2; 280 int excepts, i; 281 282 for (i = 0; i < 1 << NEXCEPTS; i++) { 283 excepts = std_except_sets[i]; 284 285 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 286 assert(fegetround() == FE_TONEAREST); 287 assert(fegetenv(&env1) == 0); 288 289 /* 290 * fe[gs]etenv() should be able to save and restore 291 * exception flags without the spurious inexact 292 * exceptions that afflict raiseexcept(). 293 */ 294 raiseexcept(excepts); 295 if ((excepts & (FE_UNDERFLOW | FE_OVERFLOW)) != 0 && 296 (excepts & FE_INEXACT) == 0) 297 assert(feclearexcept(FE_INEXACT) == 0); 298 299 fesetround(FE_DOWNWARD); 300 assert(fegetenv(&env2) == 0); 301 assert(fesetenv(&env1) == 0); 302 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 303 assert(fegetround() == FE_TONEAREST); 304 305 assert(fesetenv(&env2) == 0); 306 assert(fetestexcept(FE_ALL_EXCEPT) == excepts); 307 assert(fegetround() == FE_DOWNWARD); 308 assert(fesetenv(&env1) == 0); 309 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 310 assert(fegetround() == FE_TONEAREST); 311 } 312 } 313 314 /* 315 * Test fegetexcept(), fedisableexcept(), and feenableexcept(). 316 * 317 * Prerequisites: fetestexcept(), feraiseexcept() 318 */ 319 static void 320 test_masking(void) 321 { 322 struct sigaction act; 323 int except, i, pass, raise, status; 324 325 assert((fegetexcept() & ALL_STD_EXCEPT) == 0); 326 assert((feenableexcept(FE_INVALID|FE_OVERFLOW) & ALL_STD_EXCEPT) == 0); 327 assert((feenableexcept(FE_UNDERFLOW) & ALL_STD_EXCEPT) == 328 (FE_INVALID | FE_OVERFLOW)); 329 assert((fedisableexcept(FE_OVERFLOW) & ALL_STD_EXCEPT) == 330 (FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW)); 331 assert((fegetexcept() & ALL_STD_EXCEPT) == (FE_INVALID | FE_UNDERFLOW)); 332 assert((fedisableexcept(FE_ALL_EXCEPT) & ALL_STD_EXCEPT) == 333 (FE_INVALID | FE_UNDERFLOW)); 334 assert((fegetexcept() & ALL_STD_EXCEPT) == 0); 335 336 sigemptyset(&act.sa_mask); 337 act.sa_flags = 0; 338 act.sa_handler = trap_handler; 339 for (pass = 0; pass < 2; pass++) { 340 for (i = 0; i < NEXCEPTS; i++) { 341 except = std_excepts[i]; 342 /* over/underflow may also raise inexact */ 343 if (except == FE_INEXACT) 344 raise = FE_DIVBYZERO | FE_INVALID; 345 else 346 raise = ALL_STD_EXCEPT ^ except; 347 348 /* 349 * We need to fork a child process because 350 * there isn't a portable way to recover from 351 * a floating-point exception. 352 */ 353 switch(fork()) { 354 case 0: /* child */ 355 assert((fegetexcept() & ALL_STD_EXCEPT) == 0); 356 assert((feenableexcept(except) 357 & ALL_STD_EXCEPT) == 0); 358 assert(fegetexcept() == except); 359 raiseexcept(raise); 360 assert(feraiseexcept(raise) == 0); 361 assert(fetestexcept(ALL_STD_EXCEPT) == raise); 362 363 assert(sigaction(SIGFPE, &act, NULL) == 0); 364 switch (pass) { 365 case 0: 366 raiseexcept(except); 367 case 1: 368 feraiseexcept(except); 369 default: 370 assert(0); 371 } 372 assert(0); 373 default: /* parent */ 374 assert(wait(&status) > 0); 375 /* 376 * Avoid assert() here so that it's possible 377 * to examine a failed child's core dump. 378 */ 379 if (!WIFEXITED(status)) 380 errx(1, "child aborted\n"); 381 assert(WEXITSTATUS(status) == 0); 382 break; 383 case -1: /* error */ 384 assert(0); 385 } 386 } 387 } 388 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 389 } 390 391 /* 392 * Test feholdexcept() and feupdateenv(). 393 * 394 * Prerequisites: fetestexcept(), fegetround(), fesetround(), 395 * fedisableexcept(), feenableexcept() 396 */ 397 static void 398 test_feholdupdate(void) 399 { 400 fenv_t env; 401 402 struct sigaction act; 403 int except, i, pass, status, raise; 404 405 sigemptyset(&act.sa_mask); 406 act.sa_flags = 0; 407 act.sa_handler = trap_handler; 408 for (pass = 0; pass < 2; pass++) { 409 for (i = 0; i < NEXCEPTS; i++) { 410 except = std_excepts[i]; 411 /* over/underflow may also raise inexact */ 412 if (except == FE_INEXACT) 413 raise = FE_DIVBYZERO | FE_INVALID; 414 else 415 raise = ALL_STD_EXCEPT ^ except; 416 417 /* 418 * We need to fork a child process because 419 * there isn't a portable way to recover from 420 * a floating-point exception. 421 */ 422 switch(fork()) { 423 case 0: /* child */ 424 /* 425 * We don't want to cause a fatal exception in 426 * the child until the second pass, so we can 427 * check other properties of feupdateenv(). 428 */ 429 if (pass == 1) 430 assert((feenableexcept(except) & 431 ALL_STD_EXCEPT) == 0); 432 raiseexcept(raise); 433 assert(fesetround(FE_DOWNWARD) == 0); 434 assert(feholdexcept(&env) == 0); 435 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 436 raiseexcept(except); 437 assert(fesetround(FE_UPWARD) == 0); 438 439 if (pass == 1) 440 assert(sigaction(SIGFPE, &act, NULL) == 441 0); 442 assert(feupdateenv(&env) == 0); 443 assert(fegetround() == FE_DOWNWARD); 444 assert(fetestexcept(ALL_STD_EXCEPT) == 445 (except | raise)); 446 447 assert(pass == 0); 448 _exit(0); 449 default: /* parent */ 450 assert(wait(&status) > 0); 451 /* 452 * Avoid assert() here so that it's possible 453 * to examine a failed child's core dump. 454 */ 455 if (!WIFEXITED(status)) 456 errx(1, "child aborted\n"); 457 assert(WEXITSTATUS(status) == 0); 458 break; 459 case -1: /* error */ 460 assert(0); 461 } 462 } 463 } 464 assert(fetestexcept(FE_ALL_EXCEPT) == 0); 465 } 466 467 /* 468 * Raise a floating-point exception without relying on the standard 469 * library routines, which we are trying to test. 470 * 471 * XXX We can't raise an {over,under}flow without also raising an 472 * inexact exception. 473 */ 474 static void 475 raiseexcept(int excepts) 476 { 477 volatile double d; 478 479 /* 480 * With a compiler that supports the FENV_ACCESS pragma 481 * properly, simple expressions like '0.0 / 0.0' should 482 * be sufficient to generate traps. Unfortunately, we 483 * need to bring a volatile variable into the equation 484 * to prevent incorrect optimizations. 485 */ 486 if (excepts & FE_INVALID) { 487 d = 0.0; 488 d = 0.0 / d; 489 } 490 if (excepts & FE_DIVBYZERO) { 491 d = 0.0; 492 d = 1.0 / d; 493 } 494 if (excepts & FE_OVERFLOW) { 495 d = DBL_MAX; 496 d *= 2.0; 497 } 498 if (excepts & FE_UNDERFLOW) { 499 d = DBL_MIN; 500 d /= DBL_MAX; 501 } 502 if (excepts & FE_INEXACT) { 503 d = DBL_MIN; 504 d += 1.0; 505 } 506 507 /* 508 * On the x86 (and some other architectures?) the FPU and 509 * integer units are decoupled. We need to execute an FWAIT 510 * or a floating-point instruction to get synchronous exceptions. 511 */ 512 d = 1.0; 513 d += 1.0; 514 } 515 516 /* 517 * Determine the current rounding mode without relying on the fenv 518 * routines. This function may raise an inexact exception. 519 */ 520 static int 521 getround(void) 522 { 523 volatile double d; 524 525 /* 526 * This test works just as well with 0.0 - 0.0, except on ia64 527 * where 0.0 - 0.0 gives the wrong sign when rounding downwards. 528 */ 529 d = 1.0; 530 d -= 1.0; 531 if (copysign(1.0, d) < 0.0) 532 return (FE_DOWNWARD); 533 534 d = 1.0; 535 if (d + (DBL_EPSILON * 3.0 / 4.0) == 1.0) 536 return (FE_TOWARDZERO); 537 if (d + (DBL_EPSILON * 1.0 / 4.0) > 1.0) 538 return (FE_UPWARD); 539 540 return (FE_TONEAREST); 541 } 542 543 static void 544 trap_handler(int sig) 545 { 546 547 assert(sig == SIGFPE); 548 _exit(0); 549 } 550