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Linux 4.6-rc6
[linux/fpc-iii.git] / arch / x86 / math-emu / errors.c
blob9e6545f269e548e7cff7f4ee51876c440a7b6706
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 #if 0
37 void Un_impl(void)
38 {
39 u_char byte1, FPU_modrm;
40 unsigned long address = FPU_ORIG_EIP;
41
42 RE_ENTRANT_CHECK_OFF;
43 /* No need to check access_ok(), we have previously fetched these bytes. */
44 printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
45 if (FPU_CS == __USER_CS) {
46 while (1) {
47 FPU_get_user(byte1, (u_char __user *) address);
48 if ((byte1 & 0xf8) == 0xd8)
49 break;
50 printk("[%02x]", byte1);
51 address++;
52 }
53 printk("%02x ", byte1);
54 FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
55
56 if (FPU_modrm >= 0300)
57 printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
58 FPU_modrm & 7);
59 else
60 printk("/%d\n", (FPU_modrm >> 3) & 7);
61 } else {
62 printk("cs selector = %04x\n", FPU_CS);
63 }
64
65 RE_ENTRANT_CHECK_ON;
66
67 EXCEPTION(EX_Invalid);
68
69 }
70 #endif /* 0 */
71
72 /*
73 Called for opcodes which are illegal and which are known to result in a
74 SIGILL with a real 80486.
75 */
76 void FPU_illegal(void)
77 {
78 math_abort(FPU_info, SIGILL);
79 }
80
81 void FPU_printall(void)
82 {
83 int i;
84 static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
85 "DeNorm", "Inf", "NaN"
86 };
87 u_char byte1, FPU_modrm;
88 unsigned long address = FPU_ORIG_EIP;
89
90 RE_ENTRANT_CHECK_OFF;
91 /* No need to check access_ok(), we have previously fetched these bytes. */
92 printk("At %p:", (void *)address);
93 if (FPU_CS == __USER_CS) {
94 #define MAX_PRINTED_BYTES 20
95 for (i = 0; i < MAX_PRINTED_BYTES; i++) {
96 FPU_get_user(byte1, (u_char __user *) address);
97 if ((byte1 & 0xf8) == 0xd8) {
98 printk(" %02x", byte1);
99 break;
100 }
101 printk(" [%02x]", byte1);
102 address++;
103 }
104 if (i == MAX_PRINTED_BYTES)
105 printk(" [more..]\n");
106 else {
107 FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
108
109 if (FPU_modrm >= 0300)
110 printk(" %02x (%02x+%d)\n", FPU_modrm,
111 FPU_modrm & 0xf8, FPU_modrm & 7);
112 else
113 printk(" /%d, mod=%d rm=%d\n",
114 (FPU_modrm >> 3) & 7,
115 (FPU_modrm >> 6) & 3, FPU_modrm & 7);
116 }
117 } else {
118 printk("%04x\n", FPU_CS);
119 }
120
121 partial_status = status_word();
122
123 #ifdef DEBUGGING
124 if (partial_status & SW_Backward)
125 printk("SW: backward compatibility\n");
126 if (partial_status & SW_C3)
127 printk("SW: condition bit 3\n");
128 if (partial_status & SW_C2)
129 printk("SW: condition bit 2\n");
130 if (partial_status & SW_C1)
131 printk("SW: condition bit 1\n");
132 if (partial_status & SW_C0)
133 printk("SW: condition bit 0\n");
134 if (partial_status & SW_Summary)
135 printk("SW: exception summary\n");
136 if (partial_status & SW_Stack_Fault)
137 printk("SW: stack fault\n");
138 if (partial_status & SW_Precision)
139 printk("SW: loss of precision\n");
140 if (partial_status & SW_Underflow)
141 printk("SW: underflow\n");
142 if (partial_status & SW_Overflow)
143 printk("SW: overflow\n");
144 if (partial_status & SW_Zero_Div)
145 printk("SW: divide by zero\n");
146 if (partial_status & SW_Denorm_Op)
147 printk("SW: denormalized operand\n");
148 if (partial_status & SW_Invalid)
149 printk("SW: invalid operation\n");
150 #endif /* DEBUGGING */
151
152 printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", partial_status & 0x8000 ? 1 : 0, /* busy */
153 (partial_status & 0x3800) >> 11, /* stack top pointer */
154 partial_status & 0x80 ? 1 : 0, /* Error summary status */
155 partial_status & 0x40 ? 1 : 0, /* Stack flag */
156 partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */
157 partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */
158 partial_status & SW_Precision ? 1 : 0,
159 partial_status & SW_Underflow ? 1 : 0,
160 partial_status & SW_Overflow ? 1 : 0,
161 partial_status & SW_Zero_Div ? 1 : 0,
162 partial_status & SW_Denorm_Op ? 1 : 0,
163 partial_status & SW_Invalid ? 1 : 0);
164
165 printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n",
166 control_word & 0x1000 ? 1 : 0,
167 (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
168 (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
169 control_word & 0x80 ? 1 : 0,
170 control_word & SW_Precision ? 1 : 0,
171 control_word & SW_Underflow ? 1 : 0,
172 control_word & SW_Overflow ? 1 : 0,
173 control_word & SW_Zero_Div ? 1 : 0,
174 control_word & SW_Denorm_Op ? 1 : 0,
175 control_word & SW_Invalid ? 1 : 0);
176
177 for (i = 0; i < 8; i++) {
178 FPU_REG *r = &st(i);
179 u_char tagi = FPU_gettagi(i);
180 switch (tagi) {
181 case TAG_Empty:
182 continue;
183 break;
184 case TAG_Zero:
185 case TAG_Special:
186 tagi = FPU_Special(r);
187 case TAG_Valid:
188 printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
189 getsign(r) ? '-' : '+',
190 (long)(r->sigh >> 16),
191 (long)(r->sigh & 0xFFFF),
192 (long)(r->sigl >> 16),
193 (long)(r->sigl & 0xFFFF),
194 exponent(r) - EXP_BIAS + 1);
195 break;
196 default:
197 printk("Whoops! Error in errors.c: tag%d is %d ", i,
198 tagi);
199 continue;
200 break;
201 }
202 printk("%s\n", tag_desc[(int)(unsigned)tagi]);
203 }
204
205 RE_ENTRANT_CHECK_ON;
206
207 }
208
209 static struct {
210 int type;
211 const char *name;
212 } exception_names[] = {
213 {
214 EX_StackOver, "stack overflow"}, {
215 EX_StackUnder, "stack underflow"}, {
216 EX_Precision, "loss of precision"}, {
217 EX_Underflow, "underflow"}, {
218 EX_Overflow, "overflow"}, {
219 EX_ZeroDiv, "divide by zero"}, {
220 EX_Denormal, "denormalized operand"}, {
221 EX_Invalid, "invalid operation"}, {
222 EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
223 0, NULL}
224 };
225
226 /*
227 EX_INTERNAL is always given with a code which indicates where the
228 error was detected.
229
230 Internal error types:
231 0x14 in fpu_etc.c
232 0x1nn in a *.c file:
233 0x101 in reg_add_sub.c
234 0x102 in reg_mul.c
235 0x104 in poly_atan.c
236 0x105 in reg_mul.c
237 0x107 in fpu_trig.c
238 0x108 in reg_compare.c
239 0x109 in reg_compare.c
240 0x110 in reg_add_sub.c
241 0x111 in fpe_entry.c
242 0x112 in fpu_trig.c
243 0x113 in errors.c
244 0x115 in fpu_trig.c
245 0x116 in fpu_trig.c
246 0x117 in fpu_trig.c
247 0x118 in fpu_trig.c
248 0x119 in fpu_trig.c
249 0x120 in poly_atan.c
250 0x121 in reg_compare.c
251 0x122 in reg_compare.c
252 0x123 in reg_compare.c
253 0x125 in fpu_trig.c
254 0x126 in fpu_entry.c
255 0x127 in poly_2xm1.c
256 0x128 in fpu_entry.c
257 0x129 in fpu_entry.c
258 0x130 in get_address.c
259 0x131 in get_address.c
260 0x132 in get_address.c
261 0x133 in get_address.c
262 0x140 in load_store.c
263 0x141 in load_store.c
264 0x150 in poly_sin.c
265 0x151 in poly_sin.c
266 0x160 in reg_ld_str.c
267 0x161 in reg_ld_str.c
268 0x162 in reg_ld_str.c
269 0x163 in reg_ld_str.c
270 0x164 in reg_ld_str.c
271 0x170 in fpu_tags.c
272 0x171 in fpu_tags.c
273 0x172 in fpu_tags.c
274 0x180 in reg_convert.c
275 0x2nn in an *.S file:
276 0x201 in reg_u_add.S
277 0x202 in reg_u_div.S
278 0x203 in reg_u_div.S
279 0x204 in reg_u_div.S
280 0x205 in reg_u_mul.S
281 0x206 in reg_u_sub.S
282 0x207 in wm_sqrt.S
283 0x208 in reg_div.S
284 0x209 in reg_u_sub.S
285 0x210 in reg_u_sub.S
286 0x211 in reg_u_sub.S
287 0x212 in reg_u_sub.S
288 0x213 in wm_sqrt.S
289 0x214 in wm_sqrt.S
290 0x215 in wm_sqrt.S
291 0x220 in reg_norm.S
292 0x221 in reg_norm.S
293 0x230 in reg_round.S
294 0x231 in reg_round.S
295 0x232 in reg_round.S
296 0x233 in reg_round.S
297 0x234 in reg_round.S
298 0x235 in reg_round.S
299 0x236 in reg_round.S
300 0x240 in div_Xsig.S
301 0x241 in div_Xsig.S
302 0x242 in div_Xsig.S
303 */
304
305 asmlinkage __visible void FPU_exception(int n)
306 {
307 int i, int_type;
308
309 int_type = 0; /* Needed only to stop compiler warnings */
310 if (n & EX_INTERNAL) {
311 int_type = n - EX_INTERNAL;
312 n = EX_INTERNAL;
313 /* Set lots of exception bits! */
314 partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward);
315 } else {
316 /* Extract only the bits which we use to set the status word */
317 n &= (SW_Exc_Mask);
318 /* Set the corresponding exception bit */
319 partial_status |= n;
320 /* Set summary bits iff exception isn't masked */
321 if (partial_status & ~control_word & CW_Exceptions)
322 partial_status |= (SW_Summary | SW_Backward);
323 if (n & (SW_Stack_Fault | EX_Precision)) {
324 if (!(n & SW_C1))
325 /* This bit distinguishes over- from underflow for a stack fault,
326 and roundup from round-down for precision loss. */
327 partial_status &= ~SW_C1;
328 }
329 }
330
331 RE_ENTRANT_CHECK_OFF;
332 if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) {
333 /* Get a name string for error reporting */
334 for (i = 0; exception_names[i].type; i++)
335 if ((exception_names[i].type & n) ==
336 exception_names[i].type)
337 break;
338
339 if (exception_names[i].type) {
340 #ifdef PRINT_MESSAGES
341 printk("FP Exception: %s!\n", exception_names[i].name);
342 #endif /* PRINT_MESSAGES */
343 } else
344 printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);
345
346 if (n == EX_INTERNAL) {
347 printk("FPU emulator: Internal error type 0x%04x\n",
348 int_type);
349 FPU_printall();
350 }
351 #ifdef PRINT_MESSAGES
352 else
353 FPU_printall();
354 #endif /* PRINT_MESSAGES */
355
356 /*
357 * The 80486 generates an interrupt on the next non-control FPU
358 * instruction. So we need some means of flagging it.
359 * We use the ES (Error Summary) bit for this.
360 */
361 }
362 RE_ENTRANT_CHECK_ON;
363
364 #ifdef __DEBUG__
365 math_abort(FPU_info, SIGFPE);
366 #endif /* __DEBUG__ */
367
368 }
369
370 /* Real operation attempted on a NaN. */
371 /* Returns < 0 if the exception is unmasked */
372 int real_1op_NaN(FPU_REG *a)
373 {
374 int signalling, isNaN;
375
376 isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);
377
378 /* The default result for the case of two "equal" NaNs (signs may
379 differ) is chosen to reproduce 80486 behaviour */
380 signalling = isNaN && !(a->sigh & 0x40000000);
381
382 if (!signalling) {
383 if (!isNaN) { /* pseudo-NaN, or other unsupported? */
384 if (control_word & CW_Invalid) {
385 /* Masked response */
386 reg_copy(&CONST_QNaN, a);
387 }
388 EXCEPTION(EX_Invalid);
389 return (!(control_word & CW_Invalid) ? FPU_Exception :
390 0) | TAG_Special;
391 }
392 return TAG_Special;
393 }
394
395 if (control_word & CW_Invalid) {
396 /* The masked response */
397 if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */
398 reg_copy(&CONST_QNaN, a);
399 }
400 /* ensure a Quiet NaN */
401 a->sigh |= 0x40000000;
402 }
403
404 EXCEPTION(EX_Invalid);
405
406 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
407 }
408
409 /* Real operation attempted on two operands, one a NaN. */
410 /* Returns < 0 if the exception is unmasked */
411 int real_2op_NaN(FPU_REG const *b, u_char tagb,
412 int deststnr, FPU_REG const *defaultNaN)
413 {
414 FPU_REG *dest = &st(deststnr);
415 FPU_REG const *a = dest;
416 u_char taga = FPU_gettagi(deststnr);
417 FPU_REG const *x;
418 int signalling, unsupported;
419
420 if (taga == TAG_Special)
421 taga = FPU_Special(a);
422 if (tagb == TAG_Special)
423 tagb = FPU_Special(b);
424
425 /* TW_NaN is also used for unsupported data types. */
426 unsupported = ((taga == TW_NaN)
427 && !((exponent(a) == EXP_OVER)
428 && (a->sigh & 0x80000000)))
429 || ((tagb == TW_NaN)
430 && !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
431 if (unsupported) {
432 if (control_word & CW_Invalid) {
433 /* Masked response */
434 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
435 }
436 EXCEPTION(EX_Invalid);
437 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) |
438 TAG_Special;
439 }
440
441 if (taga == TW_NaN) {
442 x = a;
443 if (tagb == TW_NaN) {
444 signalling = !(a->sigh & b->sigh & 0x40000000);
445 if (significand(b) > significand(a))
446 x = b;
447 else if (significand(b) == significand(a)) {
448 /* The default result for the case of two "equal" NaNs (signs may
449 differ) is chosen to reproduce 80486 behaviour */
450 x = defaultNaN;
451 }
452 } else {
453 /* return the quiet version of the NaN in a */
454 signalling = !(a->sigh & 0x40000000);
455 }
456 } else
457 #ifdef PARANOID
458 if (tagb == TW_NaN)
459 #endif /* PARANOID */
460 {
461 signalling = !(b->sigh & 0x40000000);
462 x = b;
463 }
464 #ifdef PARANOID
465 else {
466 signalling = 0;
467 EXCEPTION(EX_INTERNAL | 0x113);
468 x = &CONST_QNaN;
469 }
470 #endif /* PARANOID */
471
472 if ((!signalling) || (control_word & CW_Invalid)) {
473 if (!x)
474 x = b;
475
476 if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */
477 x = &CONST_QNaN;
478
479 FPU_copy_to_regi(x, TAG_Special, deststnr);
480
481 if (!signalling)
482 return TAG_Special;
483
484 /* ensure a Quiet NaN */
485 dest->sigh |= 0x40000000;
486 }
487
488 EXCEPTION(EX_Invalid);
489
490 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
491 }
492
493 /* Invalid arith operation on Valid registers */
494 /* Returns < 0 if the exception is unmasked */
495 asmlinkage __visible int arith_invalid(int deststnr)
496 {
497
498 EXCEPTION(EX_Invalid);
499
500 if (control_word & CW_Invalid) {
501 /* The masked response */
502 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
503 }
504
505 return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid;
506
507 }
508
509 /* Divide a finite number by zero */
510 asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign)
511 {
512 FPU_REG *dest = &st(deststnr);
513 int tag = TAG_Valid;
514
515 if (control_word & CW_ZeroDiv) {
516 /* The masked response */
517 FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr);
518 setsign(dest, sign);
519 tag = TAG_Special;
520 }
521
522 EXCEPTION(EX_ZeroDiv);
523
524 return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag;
525
526 }
527
528 /* This may be called often, so keep it lean */
529 int set_precision_flag(int flags)
530 {
531 if (control_word & CW_Precision) {
532 partial_status &= ~(SW_C1 & flags);
533 partial_status |= flags; /* The masked response */
534 return 0;
535 } else {
536 EXCEPTION(flags);
537 return 1;
538 }
539 }
540
541 /* This may be called often, so keep it lean */
542 asmlinkage __visible void set_precision_flag_up(void)
543 {
544 if (control_word & CW_Precision)
545 partial_status |= (SW_Precision | SW_C1); /* The masked response */
546 else
547 EXCEPTION(EX_Precision | SW_C1);
548 }
549
550 /* This may be called often, so keep it lean */
551 asmlinkage __visible void set_precision_flag_down(void)
552 {
553 if (control_word & CW_Precision) { /* The masked response */
554 partial_status &= ~SW_C1;
555 partial_status |= SW_Precision;
556 } else
557 EXCEPTION(EX_Precision);
558 }
559
560 asmlinkage __visible int denormal_operand(void)
561 {
562 if (control_word & CW_Denormal) { /* The masked response */
563 partial_status |= SW_Denorm_Op;
564 return TAG_Special;
565 } else {
566 EXCEPTION(EX_Denormal);
567 return TAG_Special | FPU_Exception;
568 }
569 }
570
571 asmlinkage __visible int arith_overflow(FPU_REG *dest)
572 {
573 int tag = TAG_Valid;
574
575 if (control_word & CW_Overflow) {
576 /* The masked response */
577 /* ###### The response here depends upon the rounding mode */
578 reg_copy(&CONST_INF, dest);
579 tag = TAG_Special;
580 } else {
581 /* Subtract the magic number from the exponent */
582 addexponent(dest, (-3 * (1 << 13)));
583 }
584
585 EXCEPTION(EX_Overflow);
586 if (control_word & CW_Overflow) {
587 /* The overflow exception is masked. */
588 /* By definition, precision is lost.
589 The roundup bit (C1) is also set because we have
590 "rounded" upwards to Infinity. */
591 EXCEPTION(EX_Precision | SW_C1);
592 return tag;
593 }
594
595 return tag;
596
597 }
598
599 asmlinkage __visible int arith_underflow(FPU_REG *dest)
600 {
601 int tag = TAG_Valid;
602
603 if (control_word & CW_Underflow) {
604 /* The masked response */
605 if (exponent16(dest) <= EXP_UNDER - 63) {
606 reg_copy(&CONST_Z, dest);
607 partial_status &= ~SW_C1; /* Round down. */
608 tag = TAG_Zero;
609 } else {
610 stdexp(dest);
611 }
612 } else {
613 /* Add the magic number to the exponent. */
614 addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias);
615 }
616
617 EXCEPTION(EX_Underflow);
618 if (control_word & CW_Underflow) {
619 /* The underflow exception is masked. */
620 EXCEPTION(EX_Precision);
621 return tag;
622 }
623
624 return tag;
625
626 }
627
628 void FPU_stack_overflow(void)
629 {
630
631 if (control_word & CW_Invalid) {
632 /* The masked response */
633 top--;
634 FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
635 }
636
637 EXCEPTION(EX_StackOver);
638
639 return;
640
641 }
642
643 void FPU_stack_underflow(void)
644 {
645
646 if (control_word & CW_Invalid) {
647 /* The masked response */
648 FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
649 }
650
651 EXCEPTION(EX_StackUnder);
652
653 return;
654
655 }
656
657 void FPU_stack_underflow_i(int i)
658 {
659
660 if (control_word & CW_Invalid) {
661 /* The masked response */
662 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
663 }
664
665 EXCEPTION(EX_StackUnder);
666
667 return;
668
669 }
670
671 void FPU_stack_underflow_pop(int i)
672 {
673
674 if (control_word & CW_Invalid) {
675 /* The masked response */
676 FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
677 FPU_pop();
678 }
679
680 EXCEPTION(EX_StackUnder);
681
682 return;
683
684 }
Linux with added FPC-III support