aboutsummaryrefslogtreecommitdiff
path: root/gas/config/tc-moxie.c
blob: 22a29a0b74d0d1fdb12623e73826e5d554eb7a8c (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
/* tc-moxie.c -- Assemble code for moxie
   Copyright (C) 2009-2021 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.

   GAS is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 51 Franklin Street - Fifth Floor,
   Boston, MA 02110-1301, USA.  */

/* Contributed by Anthony Green <green@moxielogic.com>.  */

#include "as.h"
#include "safe-ctype.h"
#include "opcode/moxie.h"
#include "elf/moxie.h"

extern const moxie_opc_info_t moxie_opc_info[128];

const char comment_chars[]        = "#";
const char line_separator_chars[] = ";";
const char line_comment_chars[]   = "#";

static int pending_reloc;
static htab_t opcode_hash_control;

const pseudo_typeS md_pseudo_table[] =
{
  {0, 0, 0}
};

const char FLT_CHARS[] = "rRsSfFdDxXpP";
const char EXP_CHARS[] = "eE";

static valueT md_chars_to_number (char * buf, int n);

/* Byte order.  */
extern int target_big_endian;

void
md_operand (expressionS *op __attribute__((unused)))
{
  /* Empty for now. */
}

/* This function is called once, at assembler startup time.  It sets
   up the hash table with all the opcodes in it, and also initializes
   some aliases for compatibility with other assemblers.  */

void
md_begin (void)
{
  int count;
  const moxie_opc_info_t *opcode;
  opcode_hash_control = str_htab_create ();

  /* Insert names into hash table.  */
  for (count = 0, opcode = moxie_form1_opc_info; count++ < 64; opcode++)
    str_hash_insert (opcode_hash_control, opcode->name, opcode, 0);

  for (count = 0, opcode = moxie_form2_opc_info; count++ < 4; opcode++)
    str_hash_insert (opcode_hash_control, opcode->name, opcode, 0);

  for (count = 0, opcode = moxie_form3_opc_info; count++ < 10; opcode++)
    str_hash_insert (opcode_hash_control, opcode->name, opcode, 0);

  bfd_set_arch_mach (stdoutput, TARGET_ARCH, 0);
}

/* Parse an expression and then restore the input line pointer.  */

static char *
parse_exp_save_ilp (char *s, expressionS *op)
{
  char *save = input_line_pointer;

  input_line_pointer = s;
  expression (op);
  s = input_line_pointer;
  input_line_pointer = save;
  return s;
}

static int
parse_register_operand (char **ptr)
{
  int reg;
  char *s = *ptr;

  if (*s != '$')
    {
      as_bad (_("expecting register"));
      ignore_rest_of_line ();
      return -1;
    }
  if (s[1] == 'f' && s[2] == 'p')
    {
      *ptr += 3;
      return 0;
    }
  if (s[1] == 's' && s[2] == 'p')
    {
      *ptr += 3;
      return 1;
    }
  if (s[1] == 'r')
    {
      reg = s[2] - '0';
      if ((reg < 0) || (reg > 9))
	{
	  as_bad (_("illegal register number"));
	  ignore_rest_of_line ();
	  return -1;
	}
      if (reg == 1)
	{
	  int r2 = s[3] - '0';
	  if ((r2 >= 0) && (r2 <= 3))
	    {
	      reg = 10 + r2;
	      *ptr += 1;
	    }
	}
    }
  else
    {
      as_bad (_("illegal register number"));
      ignore_rest_of_line ();
      return -1;
    }

  *ptr += 3;

  return reg + 2;
}

/* This is the guts of the machine-dependent assembler.  STR points to
   a machine dependent instruction.  This function is supposed to emit
   the frags/bytes it assembles to.  */

void
md_assemble (char *str)
{
  char *op_start;
  char *op_end;

  moxie_opc_info_t *opcode;
  char *p;
  char pend;

  unsigned short iword = 0;

  int nlen = 0;

  /* Drop leading whitespace.  */
  while (*str == ' ')
    str++;

  /* Find the op code end.  */
  op_start = str;
  for (op_end = str;
       *op_end && !is_end_of_line[*op_end & 0xff] && *op_end != ' ';
       op_end++)
    nlen++;

  pend = *op_end;
  *op_end = 0;

  if (nlen == 0)
    as_bad (_("can't find opcode "));
  opcode = (moxie_opc_info_t *) str_hash_find (opcode_hash_control, op_start);
  *op_end = pend;

  if (opcode == NULL)
    {
      as_bad (_("unknown opcode %s"), op_start);
      return;
    }

  p = frag_more (2);

  switch (opcode->itype)
    {
    case MOXIE_F2_A8V:
      iword = (1<<15) | (opcode->opcode << 12);
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	int reg;
	reg = parse_register_operand (&op_end);
	iword += (reg << 8);
	if (*op_end != ',')
	  as_warn (_("expecting comma delimited register operands"));
	op_end++;
	op_end = parse_exp_save_ilp (op_end, &arg);
	fix_new_exp (frag_now,
		     ((p + (target_big_endian ? 1 : 0)) - frag_now->fr_literal),
		     1,
		     &arg,
		     0,
		     BFD_RELOC_8);
      }
      break;
    case MOXIE_F1_AB:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	int dest, src;
	dest = parse_register_operand (&op_end);
	if (*op_end != ',')
	  as_warn (_("expecting comma delimited register operands"));
	op_end++;
	src  = parse_register_operand (&op_end);
	iword += (dest << 4) + src;
	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));
      }
      break;
    case MOXIE_F1_A4:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	char *where;
	int regnum;

 	regnum = parse_register_operand (&op_end);
	while (ISSPACE (*op_end))
	  op_end++;

	iword += (regnum << 4);

	if (*op_end != ',')
	  {
	    as_bad (_("expecting comma delimited operands"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

	op_end = parse_exp_save_ilp (op_end, &arg);
	where = frag_more (4);
	fix_new_exp (frag_now,
		     (where - frag_now->fr_literal),
		     4,
		     &arg,
		     0,
		     BFD_RELOC_32);
      }
      break;
    case MOXIE_F1_M:
    case MOXIE_F1_4:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	char *where;

	op_end = parse_exp_save_ilp (op_end, &arg);
	where = frag_more (4);
	fix_new_exp (frag_now,
		     (where - frag_now->fr_literal),
		     4,
		     &arg,
		     0,
		     BFD_RELOC_32);
      }
      break;
    case MOXIE_F1_NARG:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      if (*op_end != 0)
	as_warn (_("extra stuff on line ignored"));
      break;
    case MOXIE_F1_A:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	int reg;
	reg = parse_register_operand (&op_end);
	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));
	iword += (reg << 4);
      }
      break;
    case MOXIE_F1_ABi:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	int a, b;
	a = parse_register_operand (&op_end);
	if (*op_end != ',')
	  as_warn (_("expecting comma delimited register operands"));
	op_end++;
	if (*op_end != '(')
	  {
	    as_bad (_("expecting indirect register `($rA)'"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	b = parse_register_operand (&op_end);
	if (*op_end != ')')
	  {
	    as_bad (_("missing closing parenthesis"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	iword += (a << 4) + b;
	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));
      }
      break;
    case MOXIE_F1_AiB:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	int a, b;
	if (*op_end != '(')
	  {
	    as_bad (_("expecting indirect register `($rA)'"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	a = parse_register_operand (&op_end);
	if (*op_end != ')')
	  {
	    as_bad (_("missing closing parenthesis"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	if (*op_end != ',')
	  as_warn (_("expecting comma delimited register operands"));
	op_end++;
	b = parse_register_operand (&op_end);
	iword += (a << 4) + b;
	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));
      }
      break;
    case MOXIE_F1_4A:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	char *where;
	int a;

	op_end = parse_exp_save_ilp (op_end, &arg);
	where = frag_more (4);
	fix_new_exp (frag_now,
		     (where - frag_now->fr_literal),
		     4,
		     &arg,
		     0,
		     BFD_RELOC_32);

	if (*op_end != ',')
	  {
	    as_bad (_("expecting comma delimited operands"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

 	a = parse_register_operand (&op_end);
	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));

	iword += (a << 4);
      }
      break;
    case MOXIE_F1_ABi2:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	char *offset;
	int a, b;

 	a = parse_register_operand (&op_end);
	while (ISSPACE (*op_end))
	  op_end++;

	if (*op_end != ',')
	  {
	    as_bad (_("expecting comma delimited operands"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

	op_end = parse_exp_save_ilp (op_end, &arg);
	offset = frag_more (2);
	fix_new_exp (frag_now,
		     (offset - frag_now->fr_literal),
		     2,
		     &arg,
		     0,
		     BFD_RELOC_16);

	if (*op_end != '(')
	  {
	    as_bad (_("expecting indirect register `($rX)'"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	b = parse_register_operand (&op_end);
	if (*op_end != ')')
	  {
	    as_bad (_("missing closing parenthesis"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));

	iword += (a << 4) + b;
      }
      break;
    case MOXIE_F1_AiB2:
      iword = opcode->opcode << 8;
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;
	char *offset;
	int a, b;

	op_end = parse_exp_save_ilp (op_end, &arg);
	offset = frag_more (2);
	fix_new_exp (frag_now,
		     (offset - frag_now->fr_literal),
		     2,
		     &arg,
		     0,
		     BFD_RELOC_16);

	if (*op_end != '(')
	  {
	    as_bad (_("expecting indirect register `($rX)'"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;
	a = parse_register_operand (&op_end);
	if (*op_end != ')')
	  {
	    as_bad (_("missing closing parenthesis"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

	if (*op_end != ',')
	  {
	    as_bad (_("expecting comma delimited operands"));
	    ignore_rest_of_line ();
	    return;
	  }
	op_end++;

 	b = parse_register_operand (&op_end);
	while (ISSPACE (*op_end))
	  op_end++;

	while (ISSPACE (*op_end))
	  op_end++;
	if (*op_end != 0)
	  as_warn (_("extra stuff on line ignored"));

	iword += (a << 4) + b;
      }
      break;
    case MOXIE_F2_NARG:
      iword = opcode->opcode << 12;
      while (ISSPACE (*op_end))
	op_end++;
      if (*op_end != 0)
	as_warn (_("extra stuff on line ignored"));
      break;
    case MOXIE_F3_PCREL:
      iword = (3<<14) | (opcode->opcode << 10);
      while (ISSPACE (*op_end))
	op_end++;
      {
	expressionS arg;

	op_end = parse_exp_save_ilp (op_end, &arg);
	fix_new_exp (frag_now,
		     (p - frag_now->fr_literal),
		     2,
		     &arg,
		     true,
		     BFD_RELOC_MOXIE_10_PCREL);
      }
      break;
    case MOXIE_BAD:
      iword = 0;
      while (ISSPACE (*op_end))
	op_end++;
      if (*op_end != 0)
	as_warn (_("extra stuff on line ignored"));
      break;
    default:
      abort ();
    }

  md_number_to_chars (p, iword, 2);
  dwarf2_emit_insn (2);

  while (ISSPACE (*op_end))
    op_end++;

  if (*op_end != 0)
    as_warn (_("extra stuff on line ignored"));

  if (pending_reloc)
    as_bad (_("Something forgot to clean up\n"));
}

/* Turn a string in input_line_pointer into a floating point constant
   of type type, and store the appropriate bytes in *LITP.  The number
   of LITTLENUMS emitted is stored in *SIZEP .  An error message is
   returned, or NULL on OK.  */

const char *
md_atof (int type, char *litP, int *sizeP)
{
  int prec;
  LITTLENUM_TYPE words[4];
  char *t;
  int i;

  switch (type)
    {
    case 'f':
      prec = 2;
      break;

    case 'd':
      prec = 4;
      break;

    default:
      *sizeP = 0;
      return _("bad call to md_atof");
    }

  t = atof_ieee (input_line_pointer, type, words);
  if (t)
    input_line_pointer = t;

  *sizeP = prec * 2;

  for (i = prec - 1; i >= 0; i--)
    {
      md_number_to_chars (litP, (valueT) words[i], 2);
      litP += 2;
    }

  return NULL;
}

enum options
{
  OPTION_EB = OPTION_MD_BASE,
  OPTION_EL,
};

struct option md_longopts[] =
{
  { "EB",          no_argument, NULL, OPTION_EB},
  { "EL",          no_argument, NULL, OPTION_EL},
  { NULL,          no_argument, NULL, 0}
};

size_t md_longopts_size = sizeof (md_longopts);

const char *md_shortopts = "";

int
md_parse_option (int c ATTRIBUTE_UNUSED, const char *arg ATTRIBUTE_UNUSED)
{
  switch (c)
    {
    case OPTION_EB:
      target_big_endian = 1;
      break;
    case OPTION_EL:
      target_big_endian = 0;
      break;
    default:
      return 0;
    }

  return 1;
}

void
md_show_usage (FILE *stream ATTRIBUTE_UNUSED)
{
  fprintf (stream, _("\
  -EB                     assemble for a big endian system (default)\n\
  -EL                     assemble for a little endian system\n"));
}

/* Apply a fixup to the object file.  */

void
md_apply_fix (fixS *fixP ATTRIBUTE_UNUSED,
	      valueT * valP ATTRIBUTE_UNUSED, segT seg ATTRIBUTE_UNUSED)
{
  char *buf = fixP->fx_where + fixP->fx_frag->fr_literal;
  long val = *valP;
  long newval;
  long max, min;

  max = min = 0;
  switch (fixP->fx_r_type)
    {
    case BFD_RELOC_32:
      if (target_big_endian)
	{
	  buf[0] = val >> 24;
	  buf[1] = val >> 16;
	  buf[2] = val >> 8;
	  buf[3] = val >> 0;
	}
      else
	{
	  buf[3] = val >> 24;
	  buf[2] = val >> 16;
	  buf[1] = val >> 8;
	  buf[0] = val >> 0;
	}
      buf += 4;
      break;

    case BFD_RELOC_16:
      if (target_big_endian)
	{
	  buf[0] = val >> 8;
	  buf[1] = val >> 0;
	}
      else
	{
	  buf[1] = val >> 8;
	  buf[0] = val >> 0;
	}
      buf += 2;
      break;

    case BFD_RELOC_8:
      *buf++ = val;
      break;

    case BFD_RELOC_MOXIE_10_PCREL:
      if (!val)
	break;
      if (val < -1024 || val > 1022)
	as_bad_where (fixP->fx_file, fixP->fx_line,
                      _("pcrel too far BFD_RELOC_MOXIE_10"));
      /* 11 bit offset even numbered, so we remove right bit.  */
      val >>= 1;
      newval = md_chars_to_number (buf, 2);
      newval |= val & 0x03ff;
      md_number_to_chars (buf, newval, 2);
      break;

    default:
      abort ();
    }

  if (max != 0 && (val < min || val > max))
    as_bad_where (fixP->fx_file, fixP->fx_line, _("offset out of range"));

  if (fixP->fx_addsy == NULL && fixP->fx_pcrel == 0)
    fixP->fx_done = 1;
}

/* Put number into target byte order.  */

void
md_number_to_chars (char * ptr, valueT use, int nbytes)
{
  if (target_big_endian)
    number_to_chars_bigendian (ptr, use, nbytes);
  else
    number_to_chars_littleendian (ptr, use, nbytes);
}

/* Convert from target byte order to host byte order.  */

static valueT
md_chars_to_number (char * buf, int n)
{
  valueT result = 0;
  unsigned char * where = (unsigned char *) buf;

  if (target_big_endian)
    {
      while (n--)
	{
	  result <<= 8;
	  result |= (*where++ & 255);
	}
    }
  else
    {
      while (n--)
	{
	  result <<= 8;
	  result |= (where[n] & 255);
	}
    }

  return result;
}

/* Generate a machine-dependent relocation.  */
arelent *
tc_gen_reloc (asection *section ATTRIBUTE_UNUSED, fixS *fixP)
{
  arelent *relP;
  bfd_reloc_code_real_type code;

  switch (fixP->fx_r_type)
    {
    case BFD_RELOC_32:
      code = fixP->fx_r_type;
      break;
    case BFD_RELOC_MOXIE_10_PCREL:
      code = fixP->fx_r_type;
      break;
    default:
      as_bad_where (fixP->fx_file, fixP->fx_line,
		    _("Semantics error.  This type of operand can not be relocated, it must be an assembly-time constant"));
      return 0;
    }

  relP = XNEW (arelent);
  relP->sym_ptr_ptr = XNEW (asymbol *);
  *relP->sym_ptr_ptr = symbol_get_bfdsym (fixP->fx_addsy);
  relP->address = fixP->fx_frag->fr_address + fixP->fx_where;

  relP->addend = fixP->fx_offset;

  /* This is the standard place for KLUDGEs to work around bugs in
     bfd_install_relocation (first such note in the documentation
     appears with binutils-2.8).

     That function bfd_install_relocation does the wrong thing with
     putting stuff into the addend of a reloc (it should stay out) for a
     weak symbol.  The really bad thing is that it adds the
     "segment-relative offset" of the symbol into the reloc.  In this
     case, the reloc should instead be relative to the symbol with no
     other offset than the assembly code shows; and since the symbol is
     weak, any local definition should be ignored until link time (or
     thereafter).
     To wit:  weaksym+42  should be weaksym+42 in the reloc,
     not weaksym+(offset_from_segment_of_local_weaksym_definition)

     To "work around" this, we subtract the segment-relative offset of
     "known" weak symbols.  This evens out the extra offset.

     That happens for a.out but not for ELF, since for ELF,
     bfd_install_relocation uses the "special function" field of the
     howto, and does not execute the code that needs to be undone.  */

  if (OUTPUT_FLAVOR == bfd_target_aout_flavour
      && fixP->fx_addsy && S_IS_WEAK (fixP->fx_addsy)
      && ! bfd_is_und_section (S_GET_SEGMENT (fixP->fx_addsy)))
    {
      relP->addend -= S_GET_VALUE (fixP->fx_addsy);
    }

  relP->howto = bfd_reloc_type_lookup (stdoutput, code);
  if (! relP->howto)
    {
      const char *name;

      name = S_GET_NAME (fixP->fx_addsy);
      if (name == NULL)
	name = _("<unknown>");
      as_fatal (_("Cannot generate relocation type for symbol %s, code %s"),
		name, bfd_get_reloc_code_name (code));
    }

  return relP;
}

/* Decide from what point a pc-relative relocation is relative to,
   relative to the pc-relative fixup.  Er, relatively speaking.  */
long
md_pcrel_from (fixS *fixP)
{
  valueT addr = fixP->fx_where + fixP->fx_frag->fr_address;

  switch (fixP->fx_r_type)
    {
    case BFD_RELOC_32:
      return addr + 4;
    case BFD_RELOC_MOXIE_10_PCREL:
      /* Offset is from the end of the instruction.  */
      return addr + 2;
    default:
      abort ();
      return addr;
    }
}