aboutsummaryrefslogtreecommitdiff
path: root/gdb/values.c
blob: 8fa5af9c03ad96ad656c3aefa93ca7a14b021b1d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
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
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
/* Low level packing and unpacking of values for GDB.
   Copyright (C) 1986, 1987 Free Software Foundation, Inc.

GDB is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY.  No author or distributor accepts responsibility to anyone
for the consequences of using it or for whether it serves any
particular purpose or works at all, unless he says so in writing.
Refer to the GDB General Public License for full details.

Everyone is granted permission to copy, modify and redistribute GDB,
but only under the conditions described in the GDB General Public
License.  A copy of this license is supposed to have been given to you
along with GDB so you can know your rights and responsibilities.  It
should be in a file named COPYING.  Among other things, the copyright
notice and this notice must be preserved on all copies.

In other words, go ahead and share GDB, but don't try to stop
anyone else from sharing it farther.  Help stamp out software hoarding!
*/

#include <stdio.h>
#include "defs.h"
#include "initialize.h"
#include "param.h"
#include "symtab.h"
#include "value.h"

/* The value-history records all the values printed
   by print commands during this session.  Each chunk
   records 60 consecutive values.  The first chunk on
   the chain records the most recent values.
   The total number of values is in value_history_count.  */

#define VALUE_HISTORY_CHUNK 60

struct value_history_chunk
{
  struct value_history_chunk *next;
  value values[VALUE_HISTORY_CHUNK];
};

/* Chain of chunks now in use.  */

static struct value_history_chunk *value_history_chain;

static int value_history_count;	/* Abs number of last entry stored */

START_FILE

/* List of all value objects currently allocated
   (except for those released by calls to release_value)
   This is so they can be freed after each command.  */

static value all_values;

/* Allocate a  value  that has the correct length for type TYPE.  */

value
allocate_value (type)
     struct type *type;
{
  register value val;

  val = (value) xmalloc (sizeof (struct value) + TYPE_LENGTH (type));
  VALUE_NEXT (val) = all_values;
  all_values = val;
  VALUE_TYPE (val) = type;
  VALUE_LVAL (val) = not_lval;
  VALUE_ADDRESS (val) = 0;
  VALUE_OFFSET (val) = 0;
  VALUE_BITPOS (val) = 0;
  VALUE_BITSIZE (val) = 0;
  VALUE_REPEATED (val) = 0;
  VALUE_REPETITIONS (val) = 0;
  VALUE_REGNO (val) = -1;
  return val;
}

/* Allocate a  value  that has the correct length
   for COUNT repetitions type TYPE.  */

value
allocate_repeat_value (type, count)
     struct type *type;
     int count;
{
  register value val;

  val = (value) xmalloc (sizeof (struct value) + TYPE_LENGTH (type) * count);
  VALUE_NEXT (val) = all_values;
  all_values = val;
  VALUE_TYPE (val) = type;
  VALUE_LVAL (val) = not_lval;
  VALUE_ADDRESS (val) = 0;
  VALUE_OFFSET (val) = 0;
  VALUE_BITPOS (val) = 0;
  VALUE_BITSIZE (val) = 0;
  VALUE_REPEATED (val) = 1;
  VALUE_REPETITIONS (val) = count;
  VALUE_REGNO (val) = -1;
  return val;
}

/* Free all the values that have been allocated (except for those released).
   Called after each command, successful or not.  */

void
free_all_values ()
{
  register value val, next;

  for (val = all_values; val; val = next)
    {
      next = VALUE_NEXT (val);
      free (val);
    }

  all_values = 0;
}

/* Remove VAL from the chain all_values
   so it will not be freed automatically.  */

void
release_value (val)
     register value val;
{
  register value v;

  if (all_values == val)
    {
      all_values = val->next;
      return;
    }

  for (v = all_values; v; v = v->next)
    {
      if (v->next == val)
	{
	  v->next = val->next;
	  break;
	}
    }
}

/* Return a copy of the value ARG.
   It contains the same contents, for same memory address,
   but it's a different block of storage.  */

static value
value_copy (arg)
     value arg;
{
  register value val;
  register struct type *type = VALUE_TYPE (arg);
  if (VALUE_REPEATED (arg))
    val = allocate_repeat_value (type, VALUE_REPETITIONS (arg));
  else
    val = allocate_value (type);
  VALUE_LVAL (val) = VALUE_LVAL (arg);
  VALUE_ADDRESS (val) = VALUE_ADDRESS (arg);
  VALUE_OFFSET (val) = VALUE_OFFSET (arg);
  VALUE_BITPOS (val) = VALUE_BITPOS (arg);
  VALUE_BITSIZE (val) = VALUE_BITSIZE (arg);
  VALUE_REGNO (val) = VALUE_REGNO (arg);
  bcopy (VALUE_CONTENTS (arg), VALUE_CONTENTS (val),
	 TYPE_LENGTH (VALUE_TYPE (arg))
	 * (VALUE_REPEATED (arg) ? VALUE_REPETITIONS (arg) : 1));
  return val;
}

/* Access to the value history.  */

/* Record a new value in the value history.
   Returns the absolute history index of the entry.  */

int
record_latest_value (val)
     value val;
{
  register int i;

  /* Get error now if about to store an invalid float.  */
  if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FLT)
    value_as_double (val);

  /* Here we treat value_history_count as origin-zero
     and applying to the value being stored now.  */

  i = value_history_count % VALUE_HISTORY_CHUNK;
  if (i == 0)
    {
      register struct value_history_chunk *new
	= (struct value_history_chunk *) xmalloc (sizeof (struct value_history_chunk));
      bzero (new->values, sizeof new->values);
      new->next = value_history_chain;
      value_history_chain = new;
    }

  value_history_chain->values[i] = val;
  release_value (val);

  /* Now we regard value_history_count as origin-one
     and applying to the value just stored.  */

  return ++value_history_count;
}

/* Return a copy of the value in the history with sequence number NUM.  */

value
access_value_history (num)
     int num;
{
  register struct value_history_chunk *chunk;
  register int i;
  register int absnum = num;

  if (absnum <= 0)
    absnum += value_history_count;

  if (absnum <= 0)
    {
      if (num == 0)
	error ("The history is empty.");
      else if (num == 1)
	error ("There is only one value in the history.");
      else
	error ("History does not go back to $$%d.", -num);
    }
  if (absnum > value_history_count)
    error ("History has not yet reached $%d.", absnum);

  absnum--;

  /* Now absnum is always absolute and origin zero.  */

  chunk = value_history_chain;
  for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK;
       i > 0; i--)
    chunk = chunk->next;

  return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
}

/* Clear the value history entirely.
   Must be done when new symbol tables are loaded,
   because the type pointers become invalid.  */

void
clear_value_history ()
{
  register struct value_history_chunk *next;
  register int i;
  register value val;

  while (value_history_chain)
    {
      for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
	if (val = value_history_chain->values[i])
	  free (val);
      next = value_history_chain->next;
      free (value_history_chain);
      value_history_chain = next;
    }
  value_history_count = 0;
}

static void
history_info (num_exp)
     char *num_exp;
{
  register int i;
  register value val;
  register int num;

  if (num_exp)
    num = parse_and_eval_address (num_exp) - 5;
  else
    num = value_history_count - 9;

  if (num <= 0)
    num = 1;

  for (i = num; i < num + 10 && i <= value_history_count; i++)
    {
      val = access_value_history (i);
      printf ("$%d = ", i);
      value_print (val, stdout);
      printf ("\n");
    }
}

/* Internal variables.  These are variables within the debugger
   that hold values assigned by debugger commands.
   The user refers to them with a '$' prefix
   that does not appear in the variable names stored internally.  */

static struct internalvar *internalvars;

/* Look up an internal variable with name NAME.  NAME should not
   normally include a dollar sign.

   If the specified internal variable does not exist,
   one is created, with a void value.  */

struct internalvar *
lookup_internalvar (name)
     char *name;
{
  register struct internalvar *var;

  for (var = internalvars; var; var = var->next)
    if (!strcmp (var->name, name))
      return var;

  var = (struct internalvar *) xmalloc (sizeof (struct internalvar));
  var->name = concat (name, "", "");
  var->value = allocate_value (builtin_type_void);
  release_value (var->value);
  var->next = internalvars;
  internalvars = var;
  return var;
}

value
value_of_internalvar (var)
     struct internalvar *var;
{
  register value val = value_copy (var->value);
  VALUE_LVAL (val) = lval_internalvar;
  VALUE_INTERNALVAR (val) = var;
}

void
set_internalvar_component (var, offset, bitpos, bitsize, newval)
     struct internalvar *var;
     int offset, bitpos, bitsize;
     value newval;
{
  register char *addr = VALUE_CONTENTS (var->value) + offset;
  if (bitsize)
    modify_field (addr, value_as_long (newval),
		  bitpos, bitsize);
  else
    bcopy (VALUE_CONTENTS (newval), addr,
	   TYPE_LENGTH (VALUE_TYPE (newval)));
}

void
set_internalvar (var, val)
     struct internalvar *var;
     value val;
{
  free (var->value);
  var->value = value_copy (val);
  release_value (var->value);
}

char *
internalvar_name (var)
     struct internalvar *var;
{
  return var->name;
}

/* Free all internalvars.  Done when new symtabs are loaded,
   because that makes the values invalid.  */

void
clear_internalvars ()
{
  register struct internalvar *var;

  while (internalvars)
    {
      var = internalvars;
      internalvars = var->next;
      free (var->name);
      free (var->value);
      free (var);
    }
}

static void
convenience_info ()
{
  register struct internalvar *var;

  if (internalvars)
    printf ("Debugger convenience variables:\n\n");
  else
    printf ("No debugger convenience variables now defined.\n\
Convenience variables have names starting with \"$\";\n\
use \"set\" as in \"set $foo = 5\" to define them.\n");

  for (var = internalvars; var; var = var->next)
    {
      printf ("$%s: ", var->name);
      value_print (var->value, stdout);
      printf ("\n");
    }
}

/* Extract a value as a C number (either long or double).
   Knows how to convert fixed values to double, or
   floating values to long.
   Does not deallocate the value.  */

long
value_as_long (val)
     register value val;
{
  return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val));
}

double
value_as_double (val)
     register value val;
{
  return unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val));
}

/* Unpack raw data (copied from debugee) at VALADDR
   as a long, or as a double, assuming the raw data is described
   by type TYPE.  Knows how to convert different sizes of values
   and can convert between fixed and floating point.

   C++: It is assumed that the front-end has taken care of
   all matters concerning pointers to members.  A pointer
   to member which reaches here is considered to be equivalent
   to an INT (or some size).  After all, it is only an offset.  */

long
unpack_long (type, valaddr)
     struct type *type;
     char *valaddr;
{
  register enum type_code code = TYPE_CODE (type);
  register int len = TYPE_LENGTH (type);
  register int nosign = TYPE_UNSIGNED (type);

  if (code == TYPE_CODE_ENUM)
    code = TYPE_CODE_INT;
  if (code == TYPE_CODE_FLT)
    {
      if (len == sizeof (float))
	return * (float *) valaddr;

      if (len == sizeof (double))
	return * (double *) valaddr;
    }
  else if (code == TYPE_CODE_INT && nosign)
    {
      if (len == sizeof (char))
	return * (unsigned char *) valaddr;

      if (len == sizeof (short))
	return * (unsigned short *) valaddr;

      if (len == sizeof (int))
	return * (unsigned int *) valaddr;

      if (len == sizeof (long))
	return * (unsigned long *) valaddr;
    }
  else if (code == TYPE_CODE_INT)
    {
      if (len == sizeof (char))
	return * (char *) valaddr;

      if (len == sizeof (short))
	return * (short *) valaddr;

      if (len == sizeof (int))
	return * (int *) valaddr;

      if (len == sizeof (long))
	return * (long *) valaddr;
    }
  else if (code == TYPE_CODE_PTR
	   || code == TYPE_CODE_REF)
    {
      if (len == sizeof (char *))
	return (CORE_ADDR) * (char **) valaddr;
    }
  else if (code == TYPE_CODE_MEMBER)
    error ("not impelmented: member types in unpack_long");

  error ("Value not integer or pointer.");
}

double
unpack_double (type, valaddr)
     struct type *type;
     char *valaddr;
{
  register enum type_code code = TYPE_CODE (type);
  register int len = TYPE_LENGTH (type);
  register int nosign = TYPE_UNSIGNED (type);

  if (code == TYPE_CODE_FLT)
    {
      if (INVALID_FLOAT (valaddr, len))
	error ("Invalid floating value found in program.");

      if (len == sizeof (float))
	return * (float *) valaddr;

      if (len == sizeof (double))
	return * (double *) valaddr;
    }
  else if (code == TYPE_CODE_INT && nosign)
    {
      if (len == sizeof (char))
	return * (unsigned char *) valaddr;

      if (len == sizeof (short))
	return * (unsigned short *) valaddr;

      if (len == sizeof (int))
	return * (unsigned int *) valaddr;

      if (len == sizeof (long))
	return * (unsigned long *) valaddr;
    }
  else if (code == TYPE_CODE_INT)
    {
      if (len == sizeof (char))
	return * (char *) valaddr;

      if (len == sizeof (short))
	return * (short *) valaddr;

      if (len == sizeof (int))
	return * (int *) valaddr;

      if (len == sizeof (long))
	return * (long *) valaddr;
    }

  error ("Value not floating number.");
}

/* Given a value ARG1 of a struct or union type,
   extract and return the value of one of its fields.
   FIELDNO says which field.

   For C++, must also be able to return values from static fields */

value
value_field (arg1, fieldno)
     register value arg1;
     register int fieldno;
{
  register value v;
  register struct type *type = TYPE_FIELD_TYPE (VALUE_TYPE (arg1), fieldno);
  register int offset;

  /* Handle packed fields */

  offset = TYPE_FIELD_BITPOS (VALUE_TYPE (arg1), fieldno) / 8;
  if (TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1), fieldno))
    {
      v = value_from_long (type,
			   unpack_field_as_long (VALUE_TYPE (arg1),
						 VALUE_CONTENTS (arg1),
						 fieldno));
      VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (VALUE_TYPE (arg1), fieldno) % 8;
      VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1), fieldno);
    }
  else
    {
      v = allocate_value (type);
      bcopy (VALUE_CONTENTS (arg1) + offset,
	     VALUE_CONTENTS (v),
	     TYPE_LENGTH (type));
    }
  VALUE_LVAL (v) = VALUE_LVAL (arg1);
  if (VALUE_LVAL (arg1) == lval_internalvar)
    VALUE_LVAL (v) = lval_internalvar_component;
  VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1);
  VALUE_OFFSET (v) = offset + VALUE_OFFSET (arg1);
  return v;
}

value
value_fn_field (arg1, fieldno, subfieldno)
     register value arg1;
     register int fieldno;
{
  register value v;
  struct fn_field *f = TYPE_FN_FIELDLIST1 (VALUE_TYPE (arg1), fieldno);
  register struct type *type = TYPE_FN_FIELD_TYPE (f, subfieldno);
  struct symbol *sym;

  sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, subfieldno),
		       0, VAR_NAMESPACE);
  if (! sym) error ("Internal error: could not find physical method named %s",
		    TYPE_FN_FIELD_PHYSNAME (f, subfieldno));
  
  v = allocate_value (type);
  VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
  VALUE_TYPE (v) = type;
  return v;
}

/* The value of a static class member does not depend
   on its instance, only on its type.  If FIELDNO >= 0,
   then fieldno is a valid field number and is used directly.
   Otherwise, FIELDNAME is the name of the field we are
   searching for.  If it is not a static field name, an
   error is signaled.  TYPE is the type in which we look for the
   static field member.  */
value
value_static_field (type, fieldname, fieldno)
     register struct type *type;
     char *fieldname;
     register int fieldno;
{
  register value v;
  struct symbol *sym;

  if (fieldno < 0)
    {
      register struct type *t = type;
      /* Look for static field.  */
      while (t)
	{
	  int i;
	  for (i = TYPE_NFIELDS (t) - 1; i >= 0; i--)
	    if (! strcmp (TYPE_FIELD_NAME (t, i), fieldname))
	      {
		if (TYPE_FIELD_STATIC (t, i))
		  {
		    fieldno = i;
		    goto found;
		  }
		else
		  error ("field `%s' is not static");
	      }
	  t = TYPE_BASECLASS (t);
	}

      t = type;

      if (destructor_name_p (fieldname, t))
	error ("use `info method' command to print out value of destructor");

      while (t)
	{
	  int i, j;

	  for (i = TYPE_NFN_FIELDS (t) - 1; i >= 0; i--)
	    {
	      if (! strcmp (TYPE_FN_FIELDLIST_NAME (t, i), fieldname))
		{
		  error ("use `info method' command to print value of method \"%s\"", fieldname);
		}
	    }
	  t = TYPE_BASECLASS (t);
	}
      error("there is no field named %s", fieldname);
    }

 found:

  sym = lookup_symbol (TYPE_FIELD_STATIC_PHYSNAME (type, fieldno),
		       0, VAR_NAMESPACE);
  if (! sym) error ("Internal error: could not find physical static variable named %s", TYPE_FIELD_BITSIZE (type, fieldno));

  type = TYPE_FIELD_TYPE (type, fieldno);
  v = value_at (type, (CORE_ADDR)SYMBOL_BLOCK_VALUE (sym));
  return v;
}

long
unpack_field_as_long (type, valaddr, fieldno)
     struct type *type;
     char *valaddr;
     int fieldno;
{
  long val;
  int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
  int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
  union { int i; char c; } test;

  bcopy (valaddr + bitpos / 8, &val, sizeof val);

  /* Extracting bits depends on endianness of the machine.  */
  test.i = 1;
  if (test.c == 1)
    /* Little-endian.  */
    val = val >> (bitpos % 8);
  else
    val = val >> (sizeof val * 8 - bitpos % 8 - bitsize);

  val &= (1 << bitsize) - 1;
  return val;
}

modify_field (addr, fieldval, bitpos, bitsize)
     char *addr;
     int fieldval;
     int bitpos, bitsize;
{
  long oword;
  union { int i; char c; } test;

  bcopy (addr, &oword, sizeof oword);

  /* Shifting for bit field depends on endianness of the machine.  */
  test.c = 1;
  if (test.i != 1)
    /* not little-endian: assume big-endian.  */
    bitpos = sizeof oword * 8 - bitpos - bitsize;

  oword &= ~(((1 << bitsize) - 1) << bitpos);
  oword |= fieldval << bitpos;
  bcopy (&oword, addr, sizeof oword);
}

/* Convert C numbers into newly allocated values */

value
value_from_long (type, num)
     struct type *type;
     register long num;
{
  register value val = allocate_value (type);
  register enum type_code code = TYPE_CODE (type);
  register int len = TYPE_LENGTH (type);

  if (code == TYPE_CODE_INT || code == TYPE_CODE_ENUM)
    {
      if (len == sizeof (char))
	* (char *) VALUE_CONTENTS (val) = num;
      else if (len == sizeof (short))
	* (short *) VALUE_CONTENTS (val) = num;
      else if (len == sizeof (int))
	* (int *) VALUE_CONTENTS (val) = num;
      else if (len == sizeof (long))
	* (long *) VALUE_CONTENTS (val) = num;
      else
	error ("Integer type encountered with unexpected data length.");
    }
  else
    error ("Unexpected type encountered for integer constant.");

  return val;
}

value
value_from_double (type, num)
     struct type *type;
     double num;
{
  register value val = allocate_value (type);
  register enum type_code code = TYPE_CODE (type);
  register int len = TYPE_LENGTH (type);

  if (code == TYPE_CODE_FLT)
    {
      if (len == sizeof (float))
	* (float *) VALUE_CONTENTS (val) = num;
      else if (len == sizeof (double))
	* (double *) VALUE_CONTENTS (val) = num;
      else
	error ("Floating type encountered with unexpected data length.");
    }
  else
    error ("Unexpected type encountered for floating constant.");

  return val;
}

/* Deal with the value that is "about to be returned".  */

/* Return the value that a function returning now
   would be returning to its caller, assuming its type is VALTYPE.
   RETBUF is where we look for what ought to be the contents
   of the registers (in raw form).  This is because it is often
   desirable to restore old values to those registers
   after saving the contents of interest, and then call
   this function using the saved values.  */

value
value_being_returned (valtype, retbuf)
     register struct type *valtype;
     char retbuf[REGISTER_BYTES];
{
  register value val;

  if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
      || TYPE_CODE (valtype) == TYPE_CODE_UNION)
    return value_at (valtype, EXTRACT_STRUCT_VALUE_ADDRESS (retbuf));

  val = allocate_value (valtype);
  EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS (val));

  return val;
}

/* Store VAL so it will be returned if a function returns now.
   Does not verify that VAL's type matches what the current
   function wants to return.  */

void
set_return_value (val)
     value val;
{
  register enum type_code code = TYPE_CODE (VALUE_TYPE (val));
  char regbuf[REGISTER_BYTES];
  double dbuf;
  long lbuf;

  if (code == TYPE_CODE_STRUCT
      || code == TYPE_CODE_UNION)
    error ("Specifying a struct or union return value is not supported.");

  if (code == TYPE_CODE_FLT)
    {
      dbuf = value_as_double (val);

      STORE_RETURN_VALUE (VALUE_TYPE (val), &dbuf);
    }
  else
    {
      lbuf = value_as_long (val);
      STORE_RETURN_VALUE (VALUE_TYPE (val), &lbuf);
    }
}

static
initialize ()
{
  add_info ("convenience", convenience_info,
	    "Debugger convenience (\"$foo\") variables.\n\
These variables are created when you assign them values;\n\
thus, \"print $foo=1\" gives \"$foo\" the value 1.  Values may be any type.\n\n\
A few convenience variables are given values automatically GDB:\n\
\"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
\"$__\" holds the contents of the last address examined with \"x\".");

  add_info ("history", history_info,
	    "Elements of value history (around item number IDX, or last ten).");
}

END_FILE