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/arch/i386/math-emu/errors.c

https://bitbucket.org/evzijst/gittest
C | 739 lines | 472 code | 114 blank | 153 comment | 95 complexity | ffe3bdcb2f6b90c841acae1590358245 MD5 | raw file
  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
 38void 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   */
 80void FPU_illegal(void)
 81{
 82  math_abort(FPU_info,SIGILL);
 83}
 84
 85
 86
 87void 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
133if ( partial_status & SW_Backward )    printk("SW: backward compatibility\n");
134if ( partial_status & SW_C3 )          printk("SW: condition bit 3\n");
135if ( partial_status & SW_C2 )          printk("SW: condition bit 2\n");
136if ( partial_status & SW_C1 )          printk("SW: condition bit 1\n");
137if ( partial_status & SW_C0 )          printk("SW: condition bit 0\n");
138if ( partial_status & SW_Summary )     printk("SW: exception summary\n");
139if ( partial_status & SW_Stack_Fault ) printk("SW: stack fault\n");
140if ( partial_status & SW_Precision )   printk("SW: loss of precision\n");
141if ( partial_status & SW_Underflow )   printk("SW: underflow\n");
142if ( partial_status & SW_Overflow )    printk("SW: overflow\n");
143if ( partial_status & SW_Zero_Div )    printk("SW: divide by zero\n");
144if ( partial_status & SW_Denorm_Op )   printk("SW: denormalized operand\n");
145if ( 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  
159printk(" 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
201static 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
296asmlinkage 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 */
375int 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 */
419int 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 */
513asmlinkage 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 */
530asmlinkage 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 */
551int 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 */
568asmlinkage 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 */
578asmlinkage 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
590asmlinkage 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
605asmlinkage 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
638asmlinkage 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
675void 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
692void 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
708void 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
724void 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