1 /*---------------------------------------------------------------------------+ 2 | errors.c | 3 | | 4 | The error handling functions for wm-FPU-emu | 5 | | 6 | Copyright (C) 1992,1993,1994,1996 | 7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | 8 | E-mail billm@jacobi.maths.monash.edu.au | 9 | | 10 | | 11 +---------------------------------------------------------------------------*/ 12 13 /*---------------------------------------------------------------------------+ 14 | Note: | 15 | The file contains code which accesses user memory. | 16 | Emulator static data may change when user memory is accessed, due to | 17 | other processes using the emulator while swapping is in progress. | 18 +---------------------------------------------------------------------------*/ 19 20 #include <linux/signal.h> 21 22 #include <asm/uaccess.h> 23 24 #include "fpu_emu.h" 25 #include "fpu_system.h" 26 #include "exception.h" 27 #include "status_w.h" 28 #include "control_w.h" 29 #include "reg_constant.h" 30 #include "version.h" 31 32 /* */ 33 #undef PRINT_MESSAGES 34 /* */ 35 36 37 #if 0 38 void Un_impl(void) 39 { 40 u_char byte1, FPU_modrm; 41 unsigned long address = FPU_ORIG_EIP; 42 43 RE_ENTRANT_CHECK_OFF; 44 /* No need to check access_ok(), we have previously fetched these bytes. */ 45 printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *) address); 46 if ( FPU_CS == __USER_CS ) 47 { 48 while ( 1 ) 49 { 50 FPU_get_user(byte1, (u_char __user *) address); 51 if ( (byte1 & 0xf8) == 0xd8 ) break; 52 printk("[%02x]", byte1); 53 address++; 54 } 55 printk("%02x ", byte1); 56 FPU_get_user(FPU_modrm, 1 + (u_char __user *) address); 57 58 if (FPU_modrm >= 0300) 59 printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); 60 else 61 printk("/%d\n", (FPU_modrm >> 3) & 7); 62 } 63 else 64 { 65 printk("cs selector = %04x\n", FPU_CS); 66 } 67 68 RE_ENTRANT_CHECK_ON; 69 70 EXCEPTION(EX_Invalid); 71 72 } 73 #endif /* 0 */ 74 75 76 /* 77 Called for opcodes which are illegal and which are known to result in a 78 SIGILL with a real 80486. 79 */ 80 void FPU_illegal(void) 81 { 82 math_abort(FPU_info,SIGILL); 83 } 84 85 86 87 void FPU_printall(void) 88 { 89 int i; 90 static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty", 91 "DeNorm", "Inf", "NaN" }; 92 u_char byte1, FPU_modrm; 93 unsigned long address = FPU_ORIG_EIP; 94 95 RE_ENTRANT_CHECK_OFF; 96 /* No need to check access_ok(), we have previously fetched these bytes. */ 97 printk("At %p:", (void *) address); 98 if ( FPU_CS == __USER_CS ) 99 { 100 #define MAX_PRINTED_BYTES 20 101 for ( i = 0; i < MAX_PRINTED_BYTES; i++ ) 102 { 103 FPU_get_user(byte1, (u_char __user *) address); 104 if ( (byte1 & 0xf8) == 0xd8 ) 105 { 106 printk(" %02x", byte1); 107 break; 108 } 109 printk(" [%02x]", byte1); 110 address++; 111 } 112 if ( i == MAX_PRINTED_BYTES ) 113 printk(" [more..]\n"); 114 else 115 { 116 FPU_get_user(FPU_modrm, 1 + (u_char __user *) address); 117 118 if (FPU_modrm >= 0300) 119 printk(" %02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8, FPU_modrm & 7); 120 else 121 printk(" /%d, mod=%d rm=%d\n", 122 (FPU_modrm >> 3) & 7, (FPU_modrm >> 6) & 3, FPU_modrm & 7); 123 } 124 } 125 else 126 { 127 printk("%04x\n", FPU_CS); 128 } 129 130 partial_status = status_word(); 131 132 #ifdef DEBUGGING 133 if ( partial_status & SW_Backward ) printk("SW: backward compatibility\n"); 134 if ( partial_status & SW_C3 ) printk("SW: condition bit 3\n"); 135 if ( partial_status & SW_C2 ) printk("SW: condition bit 2\n"); 136 if ( partial_status & SW_C1 ) printk("SW: condition bit 1\n"); 137 if ( partial_status & SW_C0 ) printk("SW: condition bit 0\n"); 138 if ( partial_status & SW_Summary ) printk("SW: exception summary\n"); 139 if ( partial_status & SW_Stack_Fault ) printk("SW: stack fault\n"); 140 if ( partial_status & SW_Precision ) printk("SW: loss of precision\n"); 141 if ( partial_status & SW_Underflow ) printk("SW: underflow\n"); 142 if ( partial_status & SW_Overflow ) printk("SW: overflow\n"); 143 if ( partial_status & SW_Zero_Div ) printk("SW: divide by zero\n"); 144 if ( partial_status & SW_Denorm_Op ) printk("SW: denormalized operand\n"); 145 if ( partial_status & SW_Invalid ) printk("SW: invalid operation\n"); 146 #endif /* DEBUGGING */ 147 148 printk(" SW: b=%d st=%ld es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", 149 partial_status & 0x8000 ? 1 : 0, /* busy */ 150 (partial_status & 0x3800) >> 11, /* stack top pointer */ 151 partial_status & 0x80 ? 1 : 0, /* Error summary status */ 152 partial_status & 0x40 ? 1 : 0, /* Stack flag */ 153 partial_status & SW_C3?1:0, partial_status & SW_C2?1:0, /* cc */ 154 partial_status & SW_C1?1:0, partial_status & SW_C0?1:0, /* cc */ 155 partial_status & SW_Precision?1:0, partial_status & SW_Underflow?1:0, 156 partial_status & SW_Overflow?1:0, partial_status & SW_Zero_Div?1:0, 157 partial_status & SW_Denorm_Op?1:0, partial_status & SW_Invalid?1:0); 158 159 printk(" CW: ic=%d rc=%ld%ld pc=%ld%ld iem=%d ef=%d%d%d%d%d%d\n", 160 control_word & 0x1000 ? 1 : 0, 161 (control_word & 0x800) >> 11, (control_word & 0x400) >> 10, 162 (control_word & 0x200) >> 9, (control_word & 0x100) >> 8, 163 control_word & 0x80 ? 1 : 0, 164 control_word & SW_Precision?1:0, control_word & SW_Underflow?1:0, 165 control_word & SW_Overflow?1:0, control_word & SW_Zero_Div?1:0, 166 control_word & SW_Denorm_Op?1:0, control_word & SW_Invalid?1:0); 167 168 for ( i = 0; i < 8; i++ ) 169 { 170 FPU_REG *r = &st(i); 171 u_char tagi = FPU_gettagi(i); 172 switch (tagi) 173 { 174 case TAG_Empty: 175 continue; 176 break; 177 case TAG_Zero: 178 case TAG_Special: 179 tagi = FPU_Special(r); 180 case TAG_Valid: 181 printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i, 182 getsign(r) ? '-' : '+', 183 (long)(r->sigh >> 16), 184 (long)(r->sigh & 0xFFFF), 185 (long)(r->sigl >> 16), 186 (long)(r->sigl & 0xFFFF), 187 exponent(r) - EXP_BIAS + 1); 188 break; 189 default: 190 printk("Whoops! Error in errors.c: tag%d is %d ", i, tagi); 191 continue; 192 break; 193 } 194 printk("%s\n", tag_desc[(int) (unsigned) tagi]); 195 } 196 197 RE_ENTRANT_CHECK_ON; 198 199 } 200 201 static struct { 202 int type; 203 const char *name; 204 } exception_names[] = { 205 { EX_StackOver, "stack overflow" }, 206 { EX_StackUnder, "stack underflow" }, 207 { EX_Precision, "loss of precision" }, 208 { EX_Underflow, "underflow" }, 209 { EX_Overflow, "overflow" }, 210 { EX_ZeroDiv, "divide by zero" }, 211 { EX_Denormal, "denormalized operand" }, 212 { EX_Invalid, "invalid operation" }, 213 { EX_INTERNAL, "INTERNAL BUG in "FPU_VERSION }, 214 { 0, NULL } 215 }; 216 217 /* 218 EX_INTERNAL is always given with a code which indicates where the 219 error was detected. 220 221 Internal error types: 222 0x14 in fpu_etc.c 223 0x1nn in a *.c file: 224 0x101 in reg_add_sub.c 225 0x102 in reg_mul.c 226 0x104 in poly_atan.c 227 0x105 in reg_mul.c 228 0x107 in fpu_trig.c 229 0x108 in reg_compare.c 230 0x109 in reg_compare.c 231 0x110 in reg_add_sub.c 232 0x111 in fpe_entry.c 233 0x112 in fpu_trig.c 234 0x113 in errors.c 235 0x115 in fpu_trig.c 236 0x116 in fpu_trig.c 237 0x117 in fpu_trig.c 238 0x118 in fpu_trig.c 239 0x119 in fpu_trig.c 240 0x120 in poly_atan.c 241 0x121 in reg_compare.c 242 0x122 in reg_compare.c 243 0x123 in reg_compare.c 244 0x125 in fpu_trig.c 245 0x126 in fpu_entry.c 246 0x127 in poly_2xm1.c 247 0x128 in fpu_entry.c 248 0x129 in fpu_entry.c 249 0x130 in get_address.c 250 0x131 in get_address.c 251 0x132 in get_address.c 252 0x133 in get_address.c 253 0x140 in load_store.c 254 0x141 in load_store.c 255 0x150 in poly_sin.c 256 0x151 in poly_sin.c 257 0x160 in reg_ld_str.c 258 0x161 in reg_ld_str.c 259 0x162 in reg_ld_str.c 260 0x163 in reg_ld_str.c 261 0x164 in reg_ld_str.c 262 0x170 in fpu_tags.c 263 0x171 in fpu_tags.c 264 0x172 in fpu_tags.c 265 0x180 in reg_convert.c 266 0x2nn in an *.S file: 267 0x201 in reg_u_add.S 268 0x202 in reg_u_div.S 269 0x203 in reg_u_div.S 270 0x204 in reg_u_div.S 271 0x205 in reg_u_mul.S 272 0x206 in reg_u_sub.S 273 0x207 in wm_sqrt.S 274 0x208 in reg_div.S 275 0x209 in reg_u_sub.S 276 0x210 in reg_u_sub.S 277 0x211 in reg_u_sub.S 278 0x212 in reg_u_sub.S 279 0x213 in wm_sqrt.S 280 0x214 in wm_sqrt.S 281 0x215 in wm_sqrt.S 282 0x220 in reg_norm.S 283 0x221 in reg_norm.S 284 0x230 in reg_round.S 285 0x231 in reg_round.S 286 0x232 in reg_round.S 287 0x233 in reg_round.S 288 0x234 in reg_round.S 289 0x235 in reg_round.S 290 0x236 in reg_round.S 291 0x240 in div_Xsig.S 292 0x241 in div_Xsig.S 293 0x242 in div_Xsig.S 294 */ 295 296 asmlinkage void FPU_exception(int n) 297 { 298 int i, int_type; 299 300 int_type = 0; /* Needed only to stop compiler warnings */ 301 if ( n & EX_INTERNAL ) 302 { 303 int_type = n - EX_INTERNAL; 304 n = EX_INTERNAL; 305 /* Set lots of exception bits! */ 306 partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward); 307 } 308 else 309 { 310 /* Extract only the bits which we use to set the status word */ 311 n &= (SW_Exc_Mask); 312 /* Set the corresponding exception bit */ 313 partial_status |= n; 314 /* Set summary bits iff exception isn't masked */ 315 if ( partial_status & ~control_word & CW_Exceptions ) 316 partial_status |= (SW_Summary | SW_Backward); 317 if ( n & (SW_Stack_Fault | EX_Precision) ) 318 { 319 if ( !(n & SW_C1) ) 320 /* This bit distinguishes over- from underflow for a stack fault, 321 and roundup from round-down for precision loss. */ 322 partial_status &= ~SW_C1; 323 } 324 } 325 326 RE_ENTRANT_CHECK_OFF; 327 if ( (~control_word & n & CW_Exceptions) || (n == EX_INTERNAL) ) 328 { 329 #ifdef PRINT_MESSAGES 330 /* My message from the sponsor */ 331 printk(FPU_VERSION" "__DATE__" (C) W. Metzenthen.\n"); 332 #endif /* PRINT_MESSAGES */ 333 334 /* Get a name string for error reporting */ 335 for (i=0; exception_names[i].type; i++) 336 if ( (exception_names[i].type & n) == exception_names[i].type ) 337 break; 338 339 if (exception_names[i].type) 340 { 341 #ifdef PRINT_MESSAGES 342 printk("FP Exception: %s!\n", exception_names[i].name); 343 #endif /* PRINT_MESSAGES */ 344 } 345 else 346 printk("FPU emulator: Unknown Exception: 0x%04x!\n", n); 347 348 if ( n == EX_INTERNAL ) 349 { 350 printk("FPU emulator: Internal error type 0x%04x\n", int_type); 351 FPU_printall(); 352 } 353 #ifdef PRINT_MESSAGES 354 else 355 FPU_printall(); 356 #endif /* PRINT_MESSAGES */ 357 358 /* 359 * The 80486 generates an interrupt on the next non-control FPU 360 * instruction. So we need some means of flagging it. 361 * We use the ES (Error Summary) bit for this. 362 */ 363 } 364 RE_ENTRANT_CHECK_ON; 365 366 #ifdef __DEBUG__ 367 math_abort(FPU_info,SIGFPE); 368 #endif /* __DEBUG__ */ 369 370 } 371 372 373 /* Real operation attempted on a NaN. */ 374 /* Returns < 0 if the exception is unmasked */ 375 int real_1op_NaN(FPU_REG *a) 376 { 377 int signalling, isNaN; 378 379 isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000); 380 381 /* The default result for the case of two "equal" NaNs (signs may 382 differ) is chosen to reproduce 80486 behaviour */ 383 signalling = isNaN && !(a->sigh & 0x40000000); 384 385 if ( !signalling ) 386 { 387 if ( !isNaN ) /* pseudo-NaN, or other unsupported? */ 388 { 389 if ( control_word & CW_Invalid ) 390 { 391 /* Masked response */ 392 reg_copy(&CONST_QNaN, a); 393 } 394 EXCEPTION(EX_Invalid); 395 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; 396 } 397 return TAG_Special; 398 } 399 400 if ( control_word & CW_Invalid ) 401 { 402 /* The masked response */ 403 if ( !(a->sigh & 0x80000000) ) /* pseudo-NaN ? */ 404 { 405 reg_copy(&CONST_QNaN, a); 406 } 407 /* ensure a Quiet NaN */ 408 a->sigh |= 0x40000000; 409 } 410 411 EXCEPTION(EX_Invalid); 412 413 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; 414 } 415 416 417 /* Real operation attempted on two operands, one a NaN. */ 418 /* Returns < 0 if the exception is unmasked */ 419 int real_2op_NaN(FPU_REG const *b, u_char tagb, 420 int deststnr, 421 FPU_REG const *defaultNaN) 422 { 423 FPU_REG *dest = &st(deststnr); 424 FPU_REG const *a = dest; 425 u_char taga = FPU_gettagi(deststnr); 426 FPU_REG const *x; 427 int signalling, unsupported; 428 429 if ( taga == TAG_Special ) 430 taga = FPU_Special(a); 431 if ( tagb == TAG_Special ) 432 tagb = FPU_Special(b); 433 434 /* TW_NaN is also used for unsupported data types. */ 435 unsupported = ((taga == TW_NaN) 436 && !((exponent(a) == EXP_OVER) && (a->sigh & 0x80000000))) 437 || ((tagb == TW_NaN) 438 && !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000))); 439 if ( unsupported ) 440 { 441 if ( control_word & CW_Invalid ) 442 { 443 /* Masked response */ 444 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr); 445 } 446 EXCEPTION(EX_Invalid); 447 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; 448 } 449 450 if (taga == TW_NaN) 451 { 452 x = a; 453 if (tagb == TW_NaN) 454 { 455 signalling = !(a->sigh & b->sigh & 0x40000000); 456 if ( significand(b) > significand(a) ) 457 x = b; 458 else if ( significand(b) == significand(a) ) 459 { 460 /* The default result for the case of two "equal" NaNs (signs may 461 differ) is chosen to reproduce 80486 behaviour */ 462 x = defaultNaN; 463 } 464 } 465 else 466 { 467 /* return the quiet version of the NaN in a */ 468 signalling = !(a->sigh & 0x40000000); 469 } 470 } 471 else 472 #ifdef PARANOID 473 if (tagb == TW_NaN) 474 #endif /* PARANOID */ 475 { 476 signalling = !(b->sigh & 0x40000000); 477 x = b; 478 } 479 #ifdef PARANOID 480 else 481 { 482 signalling = 0; 483 EXCEPTION(EX_INTERNAL|0x113); 484 x = &CONST_QNaN; 485 } 486 #endif /* PARANOID */ 487 488 if ( (!signalling) || (control_word & CW_Invalid) ) 489 { 490 if ( ! x ) 491 x = b; 492 493 if ( !(x->sigh & 0x80000000) ) /* pseudo-NaN ? */ 494 x = &CONST_QNaN; 495 496 FPU_copy_to_regi(x, TAG_Special, deststnr); 497 498 if ( !signalling ) 499 return TAG_Special; 500 501 /* ensure a Quiet NaN */ 502 dest->sigh |= 0x40000000; 503 } 504 505 EXCEPTION(EX_Invalid); 506 507 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; 508 } 509 510 511 /* Invalid arith operation on Valid registers */ 512 /* Returns < 0 if the exception is unmasked */ 513 asmlinkage int arith_invalid(int deststnr) 514 { 515 516 EXCEPTION(EX_Invalid); 517 518 if ( control_word & CW_Invalid ) 519 { 520 /* The masked response */ 521 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr); 522 } 523 524 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid; 525 526 } 527 528 529 /* Divide a finite number by zero */ 530 asmlinkage int FPU_divide_by_zero(int deststnr, u_char sign) 531 { 532 FPU_REG *dest = &st(deststnr); 533 int tag = TAG_Valid; 534 535 if ( control_word & CW_ZeroDiv ) 536 { 537 /* The masked response */ 538 FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr); 539 setsign(dest, sign); 540 tag = TAG_Special; 541 } 542 543 EXCEPTION(EX_ZeroDiv); 544 545 return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag; 546 547 } 548 549 550 /* This may be called often, so keep it lean */ 551 int set_precision_flag(int flags) 552 { 553 if ( control_word & CW_Precision ) 554 { 555 partial_status &= ~(SW_C1 & flags); 556 partial_status |= flags; /* The masked response */ 557 return 0; 558 } 559 else 560 { 561 EXCEPTION(flags); 562 return 1; 563 } 564 } 565 566 567 /* This may be called often, so keep it lean */ 568 asmlinkage void set_precision_flag_up(void) 569 { 570 if ( control_word & CW_Precision ) 571 partial_status |= (SW_Precision | SW_C1); /* The masked response */ 572 else 573 EXCEPTION(EX_Precision | SW_C1); 574 } 575 576 577 /* This may be called often, so keep it lean */ 578 asmlinkage void set_precision_flag_down(void) 579 { 580 if ( control_word & CW_Precision ) 581 { /* The masked response */ 582 partial_status &= ~SW_C1; 583 partial_status |= SW_Precision; 584 } 585 else 586 EXCEPTION(EX_Precision); 587 } 588 589 590 asmlinkage int denormal_operand(void) 591 { 592 if ( control_word & CW_Denormal ) 593 { /* The masked response */ 594 partial_status |= SW_Denorm_Op; 595 return TAG_Special; 596 } 597 else 598 { 599 EXCEPTION(EX_Denormal); 600 return TAG_Special | FPU_Exception; 601 } 602 } 603 604 605 asmlinkage int arith_overflow(FPU_REG *dest) 606 { 607 int tag = TAG_Valid; 608 609 if ( control_word & CW_Overflow ) 610 { 611 /* The masked response */ 612 /* ###### The response here depends upon the rounding mode */ 613 reg_copy(&CONST_INF, dest); 614 tag = TAG_Special; 615 } 616 else 617 { 618 /* Subtract the magic number from the exponent */ 619 addexponent(dest, (-3 * (1 << 13))); 620 } 621 622 EXCEPTION(EX_Overflow); 623 if ( control_word & CW_Overflow ) 624 { 625 /* The overflow exception is masked. */ 626 /* By definition, precision is lost. 627 The roundup bit (C1) is also set because we have 628 "rounded" upwards to Infinity. */ 629 EXCEPTION(EX_Precision | SW_C1); 630 return tag; 631 } 632 633 return tag; 634 635 } 636 637 638 asmlinkage int arith_underflow(FPU_REG *dest) 639 { 640 int tag = TAG_Valid; 641 642 if ( control_word & CW_Underflow ) 643 { 644 /* The masked response */ 645 if ( exponent16(dest) <= EXP_UNDER - 63 ) 646 { 647 reg_copy(&CONST_Z, dest); 648 partial_status &= ~SW_C1; /* Round down. */ 649 tag = TAG_Zero; 650 } 651 else 652 { 653 stdexp(dest); 654 } 655 } 656 else 657 { 658 /* Add the magic number to the exponent. */ 659 addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias); 660 } 661 662 EXCEPTION(EX_Underflow); 663 if ( control_word & CW_Underflow ) 664 { 665 /* The underflow exception is masked. */ 666 EXCEPTION(EX_Precision); 667 return tag; 668 } 669 670 return tag; 671 672 } 673 674 675 void FPU_stack_overflow(void) 676 { 677 678 if ( control_word & CW_Invalid ) 679 { 680 /* The masked response */ 681 top--; 682 FPU_copy_to_reg0(&CONST_QNaN, TAG_Special); 683 } 684 685 EXCEPTION(EX_StackOver); 686 687 return; 688 689 } 690 691 692 void FPU_stack_underflow(void) 693 { 694 695 if ( control_word & CW_Invalid ) 696 { 697 /* The masked response */ 698 FPU_copy_to_reg0(&CONST_QNaN, TAG_Special); 699 } 700 701 EXCEPTION(EX_StackUnder); 702 703 return; 704 705 } 706 707 708 void FPU_stack_underflow_i(int i) 709 { 710 711 if ( control_word & CW_Invalid ) 712 { 713 /* The masked response */ 714 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i); 715 } 716 717 EXCEPTION(EX_StackUnder); 718 719 return; 720 721 } 722 723 724 void FPU_stack_underflow_pop(int i) 725 { 726 727 if ( control_word & CW_Invalid ) 728 { 729 /* The masked response */ 730 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i); 731 FPU_pop(); 732 } 733 734 EXCEPTION(EX_StackUnder); 735 736 return; 737 738 } 739 740