1
2
3
4
5
6
7
8
9
10
11
12
13
14
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
|
/*---------------------------------------------------------------------------+
| errors.c |
| |
| The error handling functions for wm-FPU-emu |
| |
| Copyright (C) 1992,1993,1994,1996 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
| E-mail billm@jacobi.maths.monash.edu.au |
| |
| |
+---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------+
| Note: |
| The file contains code which accesses user memory. |
| Emulator static data may change when user memory is accessed, due to |
| other processes using the emulator while swapping is in progress. |
+---------------------------------------------------------------------------*/
#include <linux/signal.h>
#include <asm/uaccess.h>
#include "fpu_emu.h"
#include "fpu_system.h"
#include "exception.h"
#include "status_w.h"
#include "control_w.h"
#include "reg_constant.h"
#include "version.h"
/* */
#undef PRINT_MESSAGES
/* */
#if 0
void Un_impl(void)
{
u_char byte1, FPU_modrm;
unsigned long address = FPU_ORIG_EIP;
RE_ENTRANT_CHECK_OFF;
/* No need to check access_ok(), we have previously fetched these bytes. */
printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
if (FPU_CS == __USER_CS) {
while (1) {
FPU_get_user(byte1, (u_char __user *) address);
if ((byte1 & 0xf8) == 0xd8)
break;
printk("[%02x]", byte1);
address++;
}
printk("%02x ", byte1);
FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
if (FPU_modrm >= 0300)
printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
FPU_modrm & 7);
else
printk("/%d\n", (FPU_modrm >> 3) & 7);
} else {
printk("cs selector = %04x\n", FPU_CS);
}
RE_ENTRANT_CHECK_ON;
EXCEPTION(EX_Invalid);
}
#endif /* 0 */
/*
Called for opcodes which are illegal and which are known to result in a
SIGILL with a real 80486.
*/
void FPU_illegal(void)
{
math_abort(FPU_info, SIGILL);
}
void FPU_printall(void)
{
int i;
static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
"DeNorm", "Inf", "NaN"
};
u_char byte1, FPU_modrm;
unsigned long address = FPU_ORIG_EIP;
RE_ENTRANT_CHECK_OFF;
/* No need to check access_ok(), we have previously fetched these bytes. */
printk("At %p:", (void *)address);
if (FPU_CS == __USER_CS) {
#define MAX_PRINTED_BYTES 20
for (i = 0; i < MAX_PRINTED_BYTES; i++) {
FPU_get_user(byte1, (u_char __user *) address);
if ((byte1 & 0xf8) == 0xd8) {
printk(" %02x", byte1);
break;
}
printk(" [%02x]", byte1);
address++;
}
if (i == MAX_PRINTED_BYTES)
printk(" [more..]\n");
else {
FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
if (FPU_modrm >= 0300)
printk(" %02x (%02x+%d)\n", FPU_modrm,
FPU_modrm & 0xf8, FPU_modrm & 7);
else
printk(" /%d, mod=%d rm=%d\n",
(FPU_modrm >> 3) & 7,
(FPU_modrm >> 6) & 3, FPU_modrm & 7);
}
} else {
printk("%04x\n", FPU_CS);
}
partial_status = status_word();
#ifdef DEBUGGING
if (partial_status & SW_Backward)
printk("SW: backward compatibility\n");
if (partial_status & SW_C3)
printk("SW: condition bit 3\n");
if (partial_status & SW_C2)
printk("SW: condition bit 2\n");
if (partial_status & SW_C1)
printk("SW: condition bit 1\n");
if (partial_status & SW_C0)
printk("SW: condition bit 0\n");
if (partial_status & SW_Summary)
printk("SW: exception summary\n");
if (partial_status & SW_Stack_Fault)
printk("SW: stack fault\n");
if (partial_status & SW_Precision)
printk("SW: loss of precision\n");
if (partial_status & SW_Underflow)
printk("SW: underflow\n");
if (partial_status & SW_Overflow)
printk("SW: overflow\n");
if (partial_status & SW_Zero_Div)
printk("SW: divide by zero\n");
if (partial_status & SW_Denorm_Op)
printk("SW: denormalized operand\n");
if (partial_status & SW_Invalid)
printk("SW: invalid operation\n");
#endif /* DEBUGGING */
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 */
(partial_status & 0x3800) >> 11, /* stack top pointer */
partial_status & 0x80 ? 1 : 0, /* Error summary status */
partial_status & 0x40 ? 1 : 0, /* Stack flag */
partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */
partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */
partial_status & SW_Precision ? 1 : 0,
partial_status & SW_Underflow ? 1 : 0,
partial_status & SW_Overflow ? 1 : 0,
partial_status & SW_Zero_Div ? 1 : 0,
partial_status & SW_Denorm_Op ? 1 : 0,
partial_status & SW_Invalid ? 1 : 0);
printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n",
control_word & 0x1000 ? 1 : 0,
(control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
(control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
control_word & 0x80 ? 1 : 0,
control_word & SW_Precision ? 1 : 0,
control_word & SW_Underflow ? 1 : 0,
control_word & SW_Overflow ? 1 : 0,
control_word & SW_Zero_Div ? 1 : 0,
control_word & SW_Denorm_Op ? 1 : 0,
control_word & SW_Invalid ? 1 : 0);
for (i = 0; i < 8; i++) {
FPU_REG *r = &st(i);
u_char tagi = FPU_gettagi(i);
switch (tagi) {
case TAG_Empty:
continue;
break;
case TAG_Zero:
case TAG_Special:
tagi = FPU_Special(r);
case TAG_Valid:
printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
getsign(r) ? '-' : '+',
(long)(r->sigh >> 16),
(long)(r->sigh & 0xFFFF),
(long)(r->sigl >> 16),
(long)(r->sigl & 0xFFFF),
exponent(r) - EXP_BIAS + 1);
break;
default:
printk("Whoops! Error in errors.c: tag%d is %d ", i,
tagi);
continue;
break;
}
printk("%s\n", tag_desc[(int)(unsigned)tagi]);
}
RE_ENTRANT_CHECK_ON;
}
static struct {
int type;
const char *name;
} exception_names[] = {
{
EX_StackOver, "stack overflow"}, {
EX_StackUnder, "stack underflow"}, {
EX_Precision, "loss of precision"}, {
EX_Underflow, "underflow"}, {
EX_Overflow, "overflow"}, {
EX_ZeroDiv, "divide by zero"}, {
EX_Denormal, "denormalized operand"}, {
EX_Invalid, "invalid operation"}, {
EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
0, NULL}
};
/*
EX_INTERNAL is always given with a code which indicates where the
error was detected.
Internal error types:
0x14 in fpu_etc.c
0x1nn in a *.c file:
0x101 in reg_add_sub.c
0x102 in reg_mul.c
0x104 in poly_atan.c
0x105 in reg_mul.c
0x107 in fpu_trig.c
0x108 in reg_compare.c
0x109 in reg_compare.c
0x110 in reg_add_sub.c
0x111 in fpe_entry.c
0x112 in fpu_trig.c
0x113 in errors.c
0x115 in fpu_trig.c
0x116 in fpu_trig.c
0x117 in fpu_trig.c
0x118 in fpu_trig.c
0x119 in fpu_trig.c
0x120 in poly_atan.c
0x121 in reg_compare.c
0x122 in reg_compare.c
0x123 in reg_compare.c
0x125 in fpu_trig.c
0x126 in fpu_entry.c
0x127 in poly_2xm1.c
0x128 in fpu_entry.c
0x129 in fpu_entry.c
0x130 in get_address.c
0x131 in get_address.c
0x132 in get_address.c
0x133 in get_address.c
0x140 in load_store.c
0x141 in load_store.c
0x150 in poly_sin.c
0x151 in poly_sin.c
0x160 in reg_ld_str.c
0x161 in reg_ld_str.c
0x162 in reg_ld_str.c
0x163 in reg_ld_str.c
0x164 in reg_ld_str.c
0x170 in fpu_tags.c
0x171 in fpu_tags.c
0x172 in fpu_tags.c
0x180 in reg_convert.c
0x2nn in an *.S file:
0x201 in reg_u_add.S
0x202 in reg_u_div.S
0x203 in reg_u_div.S
0x204 in reg_u_div.S
0x205 in reg_u_mul.S
0x206 in reg_u_sub.S
0x207 in wm_sqrt.S
0x208 in reg_div.S
0x209 in reg_u_sub.S
0x210 in reg_u_sub.S
0x211 in reg_u_sub.S
0x212 in reg_u_sub.S
0x213 in wm_sqrt.S
0x214 in wm_sqrt.S
0x215 in wm_sqrt.S
0x220 in reg_norm.S
0x221 in reg_norm.S
0x230 in reg_round.S
0x231 in reg_round.S
0x232 in reg_round.S
0x233 in reg_round.S
0x234 in reg_round.S
0x235 in reg_round.S
0x236 in reg_round.S
0x240 in div_Xsig.S
0x241 in div_Xsig.S
0x242 in div_Xsig.S
*/
asmlinkage __visible void FPU_exception(int n)
{
int i, int_type;
int_type = 0; /* Needed only to stop compiler warnings */
if (n & EX_INTERNAL) {
int_type = n - EX_INTERNAL;
n = EX_INTERNAL;
/* Set lots of exception bits! */
partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward);
} else {
/* Extract only the bits which we use to set the status word */
n &= (SW_Exc_Mask);
/* Set the corresponding exception bit */
partial_status |= n;
/* Set summary bits iff exception isn't masked */
if (partial_status & ~control_word & CW_Exceptions)
partial_status |= (SW_Summary | SW_Backward);
if (n & (SW_Stack_Fault | EX_Precision)) {
if (!(n & SW_C1))
/* This bit distinguishes over- from underflow for a stack fault,
and roundup from round-down for precision loss. */
partial_status &= ~SW_C1;
}
}
RE_ENTRANT_CHECK_OFF;
if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) {
/* Get a name string for error reporting */
for (i = 0; exception_names[i].type; i++)
if ((exception_names[i].type & n) ==
exception_names[i].type)
break;
if (exception_names[i].type) {
#ifdef PRINT_MESSAGES
printk("FP Exception: %s!\n", exception_names[i].name);
#endif /* PRINT_MESSAGES */
} else
printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);
if (n == EX_INTERNAL) {
printk("FPU emulator: Internal error type 0x%04x\n",
int_type);
FPU_printall();
}
#ifdef PRINT_MESSAGES
else
FPU_printall();
#endif /* PRINT_MESSAGES */
/*
* The 80486 generates an interrupt on the next non-control FPU
* instruction. So we need some means of flagging it.
* We use the ES (Error Summary) bit for this.
*/
}
RE_ENTRANT_CHECK_ON;
#ifdef __DEBUG__
math_abort(FPU_info, SIGFPE);
#endif /* __DEBUG__ */
}
/* Real operation attempted on a NaN. */
/* Returns < 0 if the exception is unmasked */
int real_1op_NaN(FPU_REG *a)
{
int signalling, isNaN;
isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);
/* The default result for the case of two "equal" NaNs (signs may
differ) is chosen to reproduce 80486 behaviour */
signalling = isNaN && !(a->sigh & 0x40000000);
if (!signalling) {
if (!isNaN) { /* pseudo-NaN, or other unsupported? */
if (control_word & CW_Invalid) {
/* Masked response */
reg_copy(&CONST_QNaN, a);
}
EXCEPTION(EX_Invalid);
return (!(control_word & CW_Invalid) ? FPU_Exception :
0) | TAG_Special;
}
return TAG_Special;
}
if (control_word & CW_Invalid) {
/* The masked response */
if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */
reg_copy(&CONST_QNaN, a);
}
/* ensure a Quiet NaN */
a->sigh |= 0x40000000;
}
EXCEPTION(EX_Invalid);
return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
}
/* Real operation attempted on two operands, one a NaN. */
/* Returns < 0 if the exception is unmasked */
int real_2op_NaN(FPU_REG const *b, u_char tagb,
int deststnr, FPU_REG const *defaultNaN)
{
FPU_REG *dest = &st(deststnr);
FPU_REG const *a = dest;
u_char taga = FPU_gettagi(deststnr);
FPU_REG const *x;
int signalling, unsupported;
if (taga == TAG_Special)
taga = FPU_Special(a);
if (tagb == TAG_Special)
tagb = FPU_Special(b);
/* TW_NaN is also used for unsupported data types. */
unsupported = ((taga == TW_NaN)
&& !((exponent(a) == EXP_OVER)
&& (a->sigh & 0x80000000)))
|| ((tagb == TW_NaN)
&& !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
if (unsupported) {
if (control_word & CW_Invalid) {
/* Masked response */
FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
}
EXCEPTION(EX_Invalid);
return (!(control_word & CW_Invalid) ? FPU_Exception : 0) |
TAG_Special;
}
if (taga == TW_NaN) {
x = a;
if (tagb == TW_NaN) {
signalling = !(a->sigh & b->sigh & 0x40000000);
if (significand(b) > significand(a))
x = b;
else if (significand(b) == significand(a)) {
/* The default result for the case of two "equal" NaNs (signs may
differ) is chosen to reproduce 80486 behaviour */
x = defaultNaN;
}
} else {
/* return the quiet version of the NaN in a */
signalling = !(a->sigh & 0x40000000);
}
} else
#ifdef PARANOID
if (tagb == TW_NaN)
#endif /* PARANOID */
{
signalling = !(b->sigh & 0x40000000);
x = b;
}
#ifdef PARANOID
else {
signalling = 0;
EXCEPTION(EX_INTERNAL | 0x113);
x = &CONST_QNaN;
}
#endif /* PARANOID */
if ((!signalling) || (control_word & CW_Invalid)) {
if (!x)
x = b;
if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */
x = &CONST_QNaN;
FPU_copy_to_regi(x, TAG_Special, deststnr);
if (!signalling)
return TAG_Special;
/* ensure a Quiet NaN */
dest->sigh |= 0x40000000;
}
EXCEPTION(EX_Invalid);
return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
}
/* Invalid arith operation on Valid registers */
/* Returns < 0 if the exception is unmasked */
asmlinkage __visible int arith_invalid(int deststnr)
{
EXCEPTION(EX_Invalid);
if (control_word & CW_Invalid) {
/* The masked response */
FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
}
return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid;
}
/* Divide a finite number by zero */
asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign)
{
FPU_REG *dest = &st(deststnr);
int tag = TAG_Valid;
if (control_word & CW_ZeroDiv) {
/* The masked response */
FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr);
setsign(dest, sign);
tag = TAG_Special;
}
EXCEPTION(EX_ZeroDiv);
return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag;
}
/* This may be called often, so keep it lean */
int set_precision_flag(int flags)
{
if (control_word & CW_Precision) {
partial_status &= ~(SW_C1 & flags);
partial_status |= flags; /* The masked response */
return 0;
} else {
EXCEPTION(flags);
return 1;
}
}
/* This may be called often, so keep it lean */
asmlinkage __visible void set_precision_flag_up(void)
{
if (control_word & CW_Precision)
partial_status |= (SW_Precision | SW_C1); /* The masked response */
else
EXCEPTION(EX_Precision | SW_C1);
}
/* This may be called often, so keep it lean */
asmlinkage __visible void set_precision_flag_down(void)
{
if (control_word & CW_Precision) { /* The masked response */
partial_status &= ~SW_C1;
partial_status |= SW_Precision;
} else
EXCEPTION(EX_Precision);
}
asmlinkage __visible int denormal_operand(void)
{
if (control_word & CW_Denormal) { /* The masked response */
partial_status |= SW_Denorm_Op;
return TAG_Special;
} else {
EXCEPTION(EX_Denormal);
return TAG_Special | FPU_Exception;
}
}
asmlinkage __visible int arith_overflow(FPU_REG *dest)
{
int tag = TAG_Valid;
if (control_word & CW_Overflow) {
/* The masked response */
/* ###### The response here depends upon the rounding mode */
reg_copy(&CONST_INF, dest);
tag = TAG_Special;
} else {
/* Subtract the magic number from the exponent */
addexponent(dest, (-3 * (1 << 13)));
}
EXCEPTION(EX_Overflow);
if (control_word & CW_Overflow) {
/* The overflow exception is masked. */
/* By definition, precision is lost.
The roundup bit (C1) is also set because we have
"rounded" upwards to Infinity. */
EXCEPTION(EX_Precision | SW_C1);
return tag;
}
return tag;
}
asmlinkage __visible int arith_underflow(FPU_REG *dest)
{
int tag = TAG_Valid;
if (control_word & CW_Underflow) {
/* The masked response */
if (exponent16(dest) <= EXP_UNDER - 63) {
reg_copy(&CONST_Z, dest);
partial_status &= ~SW_C1; /* Round down. */
tag = TAG_Zero;
} else {
stdexp(dest);
}
} else {
/* Add the magic number to the exponent. */
addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias);
}
EXCEPTION(EX_Underflow);
if (control_word & CW_Underflow) {
/* The underflow exception is masked. */
EXCEPTION(EX_Precision);
return tag;
}
return tag;
}
void FPU_stack_overflow(void)
{
if (control_word & CW_Invalid) {
/* The masked response */
top--;
FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
}
EXCEPTION(EX_StackOver);
return;
}
void FPU_stack_underflow(void)
{
if (control_word & CW_Invalid) {
/* The masked response */
FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
}
EXCEPTION(EX_StackUnder);
return;
}
void FPU_stack_underflow_i(int i)
{
if (control_word & CW_Invalid) {
/* The masked response */
FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
}
EXCEPTION(EX_StackUnder);
return;
}
void FPU_stack_underflow_pop(int i)
{
if (control_word & CW_Invalid) {
/* The masked response */
FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
FPU_pop();
}
EXCEPTION(EX_StackUnder);
return;
}
|