opcodes/arm-dis.c

   1 /* Instruction printing code for the ARM
   2    Copyright (C) 1994, 95, 96, 97, 1998 Free Software Foundation, Inc.
   3    Contributed by Richard Earnshaw (rwe@pegasus.esprit.ec.org)
   4    Modification by James G. Smith (jsmith@cygnus.co.uk)
   5
   6 This file is part of libopcodes.
   7
   8 This program is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2 of the License, or (at your option)
  11 any later version.
  12
  13 This program is distributed in the hope that it will be useful, but WITHOUT
  14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  16 more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "dis-asm.h"
  23 #define DEFINE_TABLE
  24 #include "arm-opc.h"
  25 #include "coff/internal.h"
  26 #include "libcoff.h"
  27 #include "opintl.h"
  28
  29 /* FIXME: This shouldn't be done here */
  30 #include "elf-bfd.h"
  31 #include "elf/internal.h"
  32
  33 static char *arm_conditional[] =
  34 {"eq", "ne", "cs", "cc", "mi", "pl", "vs", "vc",
  35  "hi", "ls", "ge", "lt", "gt", "le", "", "nv"};
  36
  37 static char *arm_regnames[] =
  38 {"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  39  "r8", "r9", "sl", "fp", "ip", "sp", "lr", "pc"};
  40
  41 static char *arm_fp_const[] =
  42 {"0.0", "1.0", "2.0", "3.0", "4.0", "5.0", "0.5", "10.0"};
  43
  44 static char *arm_shift[] =
  45 {"lsl", "lsr", "asr", "ror"};
  46
  47 static int print_insn_arm PARAMS ((bfd_vma, struct disassemble_info *,
  48                                    long));
  49
  50 static void
  51 arm_decode_shift (given, func, stream)
  52      long given;
  53      fprintf_ftype func;
  54      void *stream;
  55 {
  56   func (stream, "%s", arm_regnames[given & 0xf]);
  57   if ((given & 0xff0) != 0)
  58     {
  59       if ((given & 0x10) == 0)
  60         {
  61           int amount = (given & 0xf80) >> 7;
  62           int shift = (given & 0x60) >> 5;
  63           if (amount == 0)
  64             {
  65               if (shift == 3)
  66                 {
  67                   func (stream, ", rrx");
  68                   return;
  69                 }
  70               amount = 32;
  71             }
  72           func (stream, ", %s #%d", arm_shift[shift], amount);
  73         }
  74       else
  75         func (stream, ", %s %s", arm_shift[(given & 0x60) >> 5],
  76               arm_regnames[(given & 0xf00) >> 8]);
  77     }
  78 }
  79
  80 /* Print one instruction from PC on INFO->STREAM.
  81    Return the size of the instruction (always 4 on ARM). */
  82
  83 static int
  84 print_insn_arm (pc, info, given)
  85      bfd_vma         pc;
  86      struct disassemble_info *info;
  87      long given;
  88 {
  89   struct arm_opcode *insn;
  90   void *stream = info->stream;
  91   fprintf_ftype func = info->fprintf_func;
  92
  93   for (insn = arm_opcodes; insn->assembler; insn++)
  94     {
  95       if ((given & insn->mask) == insn->value)
  96         {
  97           char *c;
  98           for (c = insn->assembler; *c; c++)
  99             {
 100               if (*c == '%')
 101                 {
 102                   switch (*++c)
 103                     {
 104                     case '%':
 105                       func (stream, "%%");
 106                       break;
 107
 108                     case 'a':
 109                       if (((given & 0x000f0000) == 0x000f0000)
 110                           && ((given & 0x02000000) == 0))
 111                         {
 112                           int offset = given & 0xfff;
 113                           if ((given & 0x00800000) == 0)
 114                             offset = -offset;
 115                           (*info->print_address_func)
 116                             (offset + pc + 8, info);
 117                         }
 118                       else
 119                         {
 120                           func (stream, "[%s",
 121                                 arm_regnames[(given >> 16) & 0xf]);
 122                           if ((given & 0x01000000) != 0)
 123                             {
 124                               if ((given & 0x02000000) == 0)
 125                                 {
 126                                   int offset = given & 0xfff;
 127                                   if (offset)
 128                                     func (stream, ", %s#%d",
 129                                           (((given & 0x00800000) == 0)
 130                                            ? "-" : ""), offset);
 131                                 }
 132                               else
 133                                 {
 134                                   func (stream, ", %s",
 135                                         (((given & 0x00800000) == 0)
 136                                          ? "-" : ""));
 137                                   arm_decode_shift (given, func, stream);
 138                                 }
 139
 140                               func (stream, "]%s",
 141                                     ((given & 0x00200000) != 0) ? "!" : "");
 142                             }
 143                           else
 144                             {
 145                               if ((given & 0x02000000) == 0)
 146                                 {
 147                                   int offset = given & 0xfff;
 148                                   if (offset)
 149                                     func (stream, "], %s#%d",
 150                                           (((given & 0x00800000) == 0)
 151                                            ? "-" : ""), offset);
 152                                   else
 153                                     func (stream, "]");
 154                                 }
 155                               else
 156                                 {
 157                                   func (stream, "], %s",
 158                                         (((given & 0x00800000) == 0)
 159                                          ? "-" : ""));
 160                                   arm_decode_shift (given, func, stream);
 161                                 }
 162                             }
 163                         }
 164                       break;
 165
 166                     case 's':
 167                       if ((given & 0x004f0000) == 0x004f0000)
 168                         {
 169                           /* PC relative with immediate offset */
 170                           int offset = ((given & 0xf00) >> 4) | (given & 0xf);
 171                           if ((given & 0x00800000) == 0)
 172                             offset = -offset;
 173                           (*info->print_address_func)
 174                             (offset + pc + 8, info);
 175                         }
 176                       else
 177                         {
 178                           func (stream, "[%s",
 179                                 arm_regnames[(given >> 16) & 0xf]);
 180                           if ((given & 0x01000000) != 0)
 181                             {
 182                               /* pre-indexed */
 183                               if ((given & 0x00400000) == 0x00400000)
 184                                 {
 185                                   /* immediate */
 186                                   int offset = ((given & 0xf00) >> 4) | (given & 0xf);
 187                                   if (offset)
 188                                     func (stream, ", %s#%d",
 189                                           (((given & 0x00800000) == 0)
 190                                            ? "-" : ""), offset);
 191                                 }
 192                               else
 193                                 {
 194                                   /* register */
 195                                   func (stream, ", %s%s",
 196                                         (((given & 0x00800000) == 0)
 197                                          ? "-" : ""),
 198                                         arm_regnames[given & 0xf]);
 199                                 }
 200
 201                               func (stream, "]%s",
 202                                     ((given & 0x00200000) != 0) ? "!" : "");
 203                             }
 204                           else
 205                             {
 206                               /* post-indexed */
 207                               if ((given & 0x00400000) == 0x00400000)
 208                                 {
 209                                   /* immediate */
 210                                   int offset = ((given & 0xf00) >> 4) | (given & 0xf);
 211                                   if (offset)
 212                                     func (stream, "], %s#%d",
 213                                           (((given & 0x00800000) == 0)
 214                                            ? "-" : ""), offset);
 215                                   else
 216                                     func (stream, "]");
 217                                 }
 218                               else
 219                                 {
 220                                   /* register */
 221                                   func (stream, "], %s%s",
 222                                         (((given & 0x00800000) == 0)
 223                                          ? "-" : ""),
 224                                         arm_regnames[given & 0xf]);
 225                                 }
 226                             }
 227                         }
 228                       break;
 229
 230                     case 'b':
 231                       (*info->print_address_func)
 232                         (BDISP (given) * 4 + pc + 8, info);
 233                       break;
 234
 235                     case 'c':
 236                       func (stream, "%s",
 237                             arm_conditional [(given >> 28) & 0xf]);
 238                       break;
 239
 240                     case 'm':
 241                       {
 242                         int started = 0;
 243                         int reg;
 244
 245                         func (stream, "{");
 246                         for (reg = 0; reg < 16; reg++)
 247                           if ((given & (1 << reg)) != 0)
 248                             {
 249                               if (started)
 250                                 func (stream, ", ");
 251                               started = 1;
 252                               func (stream, "%s", arm_regnames[reg]);
 253                             }
 254                         func (stream, "}");
 255                       }
 256                       break;
 257
 258                     case 'o':
 259                       if ((given & 0x02000000) != 0)
 260                         {
 261                           int rotate = (given & 0xf00) >> 7;
 262                           int immed = (given & 0xff);
 263                           func (stream, "#%d",
 264                                 ((immed << (32 - rotate))
 265                                  | (immed >> rotate)) & 0xffffffff);
 266                         }
 267                       else
 268                         arm_decode_shift (given, func, stream);
 269                       break;
 270
 271                     case 'p':
 272                       if ((given & 0x0000f000) == 0x0000f000)
 273                         func (stream, "p");
 274                       break;
 275
 276                     case 't':
 277                       if ((given & 0x01200000) == 0x00200000)
 278                         func (stream, "t");
 279                       break;
 280
 281                     case 'h':
 282                       if ((given & 0x00000020) == 0x00000020)
 283                         func (stream, "h");
 284                       else
 285                         func (stream, "b");
 286                       break;
 287
 288                     case 'A':
 289                       func (stream, "[%s", arm_regnames [(given >> 16) & 0xf]);
 290                       if ((given & 0x01000000) != 0)
 291                         {
 292                           int offset = given & 0xff;
 293                           if (offset)
 294                             func (stream, ", %s#%d]%s",
 295                                   ((given & 0x00800000) == 0 ? "-" : ""),
 296                                   offset * 4,
 297                                   ((given & 0x00200000) != 0 ? "!" : ""));
 298                           else
 299                             func (stream, "]");
 300                         }
 301                       else
 302                         {
 303                           int offset = given & 0xff;
 304                           if (offset)
 305                             func (stream, "], %s#%d",
 306                                   ((given & 0x00800000) == 0 ? "-" : ""),
 307                                   offset * 4);
 308                           else
 309                             func (stream, "]");
 310                         }
 311                       break;
 312
 313                     case 'C':
 314                       switch (given & 0x00090000)
 315                         {
 316                         default:
 317                           func (stream, "_???");
 318                           break;
 319                         case 0x90000:
 320                           func (stream, "_all");
 321                           break;
 322                         case 0x10000:
 323                           func (stream, "_ctl");
 324                           break;
 325                         case 0x80000:
 326                           func (stream, "_flg");
 327                           break;
 328                         }
 329                       break;
 330
 331                     case 'F':
 332                       switch (given & 0x00408000)
 333                         {
 334                         case 0:
 335                           func (stream, "4");
 336                           break;
 337                         case 0x8000:
 338                           func (stream, "1");
 339                           break;
 340                         case 0x00400000:
 341                           func (stream, "2");
 342                           break;
 343                         default:
 344                           func (stream, "3");
 345                         }
 346                       break;
 347
 348                     case 'P':
 349                       switch (given & 0x00080080)
 350                         {
 351                         case 0:
 352                           func (stream, "s");
 353                           break;
 354                         case 0x80:
 355                           func (stream, "d");
 356                           break;
 357                         case 0x00080000:
 358                           func (stream, "e");
 359                           break;
 360                         default:
 361                           func (stream, _("<illegal precision>"));
 362                           break;
 363                         }
 364                       break;
 365                     case 'Q':
 366                       switch (given & 0x00408000)
 367                         {
 368                         case 0:
 369                           func (stream, "s");
 370                           break;
 371                         case 0x8000:
 372                           func (stream, "d");
 373                           break;
 374                         case 0x00400000:
 375                           func (stream, "e");
 376                           break;
 377                         default:
 378                           func (stream, "p");
 379                           break;
 380                         }
 381                       break;
 382                     case 'R':
 383                       switch (given & 0x60)
 384                         {
 385                         case 0:
 386                           break;
 387                         case 0x20:
 388                           func (stream, "p");
 389                           break;
 390                         case 0x40:
 391                           func (stream, "m");
 392                           break;
 393                         default:
 394                           func (stream, "z");
 395                           break;
 396                         }
 397                       break;
 398
 399                     case '0': case '1': case '2': case '3': case '4':
 400                     case '5': case '6': case '7': case '8': case '9':
 401                       {
 402                         int bitstart = *c++ - '0';
 403                         int bitend = 0;
 404                         while (*c >= '0' && *c <= '9')
 405                           bitstart = (bitstart * 10) + *c++ - '0';
 406
 407                         switch (*c)
 408                           {
 409                           case '-':
 410                             c++;
 411                             while (*c >= '0' && *c <= '9')
 412                               bitend = (bitend * 10) + *c++ - '0';
 413                             if (!bitend)
 414                               abort ();
 415                             switch (*c)
 416                               {
 417                               case 'r':
 418                                 {
 419                                   long reg;
 420                                   reg = given >> bitstart;
 421                                   reg &= (2 << (bitend - bitstart)) - 1;
 422                                   func (stream, "%s", arm_regnames[reg]);
 423                                 }
 424                                 break;
 425                               case 'd':
 426                                 {
 427                                   long reg;
 428                                   reg = given >> bitstart;
 429                                   reg &= (2 << (bitend - bitstart)) - 1;
 430                                   func (stream, "%d", reg);
 431                                 }
 432                                 break;
 433                               case 'x':
 434                                 {
 435                                   long reg;
 436                                   reg = given >> bitstart;
 437                                   reg &= (2 << (bitend - bitstart)) - 1;
 438                                   func (stream, "0x%08x", reg);
 439                                 }
 440                                 break;
 441                               case 'f':
 442                                 {
 443                                   long reg;
 444                                   reg = given >> bitstart;
 445                                   reg &= (2 << (bitend - bitstart)) - 1;
 446                                   if (reg > 7)
 447                                     func (stream, "#%s",
 448                                           arm_fp_const[reg & 7]);
 449                                   else
 450                                     func (stream, "f%d", reg);
 451                                 }
 452                                 break;
 453                               default:
 454                                 abort ();
 455                               }
 456                             break;
 457                           case '`':
 458                             c++;
 459                             if ((given & (1 << bitstart)) == 0)
 460                               func (stream, "%c", *c);
 461                             break;
 462                           case '\'':
 463                             c++;
 464                             if ((given & (1 << bitstart)) != 0)
 465                               func (stream, "%c", *c);
 466                             break;
 467                           case '?':
 468                             ++c;
 469                             if ((given & (1 << bitstart)) != 0)
 470                               func (stream, "%c", *c++);
 471                             else
 472                               func (stream, "%c", *++c);
 473                             break;
 474                           default:
 475                             abort ();
 476                           }
 477                         break;
 478
 479                       default:
 480                         abort ();
 481                       }
 482                     }
 483                 }
 484               else
 485                 func (stream, "%c", *c);
 486             }
 487           return 4;
 488         }
 489     }
 490   abort ();
 491 }
 492
 493 /* Print one instruction from PC on INFO->STREAM.
 494    Return the size of the instruction. */
 495
 496 static int
 497 print_insn_thumb (pc, info, given)
 498      bfd_vma         pc;
 499      struct disassemble_info *info;
 500      long given;
 501 {
 502   struct thumb_opcode *insn;
 503   void *stream = info->stream;
 504   fprintf_ftype func = info->fprintf_func;
 505
 506   for (insn = thumb_opcodes; insn->assembler; insn++)
 507     {
 508       if ((given & insn->mask) == insn->value)
 509         {
 510           char *c = insn->assembler;
 511
 512           /* Special processing for Thumb 2 instruction BL sequence: */
 513           if (!*c) /* check for empty (not NULL) assembler string */
 514             {
 515               info->bytes_per_chunk = 4;
 516               info->bytes_per_line  = 4;
 517
 518               func (stream, "%04x\tbl\t", given & 0xffff);
 519               (*info->print_address_func)
 520                 (BDISP23 (given) * 2 + pc + 4, info);
 521               return 4;
 522             }
 523           else
 524             {
 525               info->bytes_per_chunk = 2;
 526               info->bytes_per_line  = 4;
 527
 528               given &= 0xffff;
 529               func (stream, "%04x\t", given);
 530               for (; *c; c++)
 531                 {
 532                   if (*c == '%')
 533                     {
 534                       int domaskpc = 0;
 535                       int domasklr = 0;
 536                       switch (*++c)
 537                         {
 538                         case '%':
 539                           func (stream, "%%");
 540                           break;
 541
 542                         case 'S':
 543                           {
 544                             long reg;
 545                             reg = (given >> 3) & 0x7;
 546                             if (given & (1 << 6))
 547                               reg += 8;
 548                             func (stream, "%s", arm_regnames[reg]);
 549                           }
 550                           break;
 551
 552                         case 'D':
 553                           {
 554                             long reg;
 555                             reg = given & 0x7;
 556                             if (given & (1 << 7))
 557                              reg += 8;
 558                             func (stream, "%s", arm_regnames[reg]);
 559                           }
 560                           break;
 561
 562                         case 'T':
 563                           func (stream, "%s",
 564                                 arm_conditional [(given >> 8) & 0xf]);
 565                           break;
 566
 567                         case 'N':
 568                           if (given & (1 << 8))
 569                             domasklr = 1;
 570                           /* fall through */
 571                         case 'O':
 572                           if (*c == 'O' && (given & (1 << 8)))
 573                             domaskpc = 1;
 574                           /* fall through */
 575                         case 'M':
 576                           {
 577                             int started = 0;
 578                             int reg;
 579                             func (stream, "{");
 580                             /* It would be nice if we could spot
 581                                ranges, and generate the rS-rE format: */
 582                             for (reg = 0; (reg < 8); reg++)
 583                               if ((given & (1 << reg)) != 0)
 584                                 {
 585                                   if (started)
 586                                     func (stream, ", ");
 587                                   started = 1;
 588                                   func (stream, "%s", arm_regnames[reg]);
 589                                 }
 590
 591                             if (domasklr)
 592                               {
 593                                 if (started)
 594                                   func (stream, ", ");
 595                                 started = 1;
 596                                 func (stream, "lr");
 597                               }
 598
 599                             if (domaskpc)
 600                               {
 601                                 if (started)
 602                                   func (stream, ", ");
 603                                 func (stream, "pc");
 604                               }
 605
 606                             func (stream, "}");
 607                           }
 608                           break;
 609
 610
 611                         case '0': case '1': case '2': case '3': case '4':
 612                         case '5': case '6': case '7': case '8': case '9':
 613                           {
 614                             int bitstart = *c++ - '0';
 615                             int bitend = 0;
 616                             while (*c >= '0' && *c <= '9')
 617                               bitstart = (bitstart * 10) + *c++ - '0';
 618
 619                             switch (*c)
 620                               {
 621                               case '-':
 622                                 {
 623                                   long reg;
 624                                   c++;
 625                                   while (*c >= '0' && *c <= '9')
 626                                     bitend = (bitend * 10) + *c++ - '0';
 627                                   if (!bitend)
 628                                     abort ();
 629                                   reg = given >> bitstart;
 630                                   reg &= (2 << (bitend - bitstart)) - 1;
 631                                   switch (*c)
 632                                     {
 633                                     case 'r':
 634                                       func (stream, "%s", arm_regnames[reg]);
 635                                       break;
 636
 637                                     case 'd':
 638                                       func (stream, "%d", reg);
 639                                       break;
 640
 641                                     case 'H':
 642                                       func (stream, "%d", reg << 1);
 643                                       break;
 644
 645                                     case 'W':
 646                                       func (stream, "%d", reg << 2);
 647                                       break;
 648
 649                                     case 'a':
 650                                       /* PC-relative address -- the bottom two
 651                                          bits of the address are dropped before
 652                                          the calculation.  */
 653                                       info->print_address_func
 654                                         (((pc + 4) & ~3) + (reg << 2), info);
 655                                       break;
 656
 657                                     case 'x':
 658                                       func (stream, "0x%04x", reg);
 659                                       break;
 660
 661                                     case 'I':
 662                                       reg = ((reg ^ (1 << bitend)) - (1 << bitend));
 663                                       func (stream, "%d", reg);
 664                                       break;
 665
 666                                     case 'B':
 667                                       reg = ((reg ^ (1 << bitend)) - (1 << bitend));
 668                                       (*info->print_address_func)
 669                                         (reg * 2 + pc + 4, info);
 670                                       break;
 671
 672                                     default:
 673                                       abort();
 674                                     }
 675                                 }
 676                                 break;
 677
 678                               case '\'':
 679                                 c++;
 680                                 if ((given & (1 << bitstart)) != 0)
 681                                   func (stream, "%c", *c);
 682                                 break;
 683
 684                               case '?':
 685                                 ++c;
 686                                 if ((given & (1 << bitstart)) != 0)
 687                                   func (stream, "%c", *c++);
 688                                 else
 689                                   func (stream, "%c", *++c);
 690                                 break;
 691
 692                               default:
 693                                  abort();
 694                               }
 695                           }
 696                           break;
 697
 698                         default:
 699                           abort ();
 700                         }
 701                     }
 702                   else
 703                     func (stream, "%c", *c);
 704                 }
 705              }
 706           return 2;
 707        }
 708     }
 709
 710   /* no match */
 711   abort ();
 712 }
 713
 714 /* NOTE: There are no checks in these routines that the relevant number of data bytes exist */
 715
 716 int
 717 print_insn_big_arm (pc, info)
 718      bfd_vma pc;
 719      struct disassemble_info *info;
 720 {
 721   unsigned char      b[4];
 722   long               given;
 723   int                status;
 724   coff_symbol_type   *cs;
 725   elf_symbol_type    *es;
 726   int                is_thumb;
 727
 728   is_thumb = false;
 729   if (info->symbols != NULL)
 730     {
 731     if (bfd_asymbol_flavour (*info->symbols) == bfd_target_coff_flavour)
 732      {
 733        cs = coffsymbol (*info->symbols);
 734        is_thumb = (cs->native->u.syment.n_sclass == C_THUMBEXT
 735                    || cs->native->u.syment.n_sclass == C_THUMBSTAT
 736                    || cs->native->u.syment.n_sclass == C_THUMBLABEL
 737                    || cs->native->u.syment.n_sclass == C_THUMBEXTFUNC
 738                    || cs->native->u.syment.n_sclass == C_THUMBSTATFUNC);
 739
 740      }
 741     else if (bfd_asymbol_flavour (*info->symbols) == bfd_target_elf_flavour)
 742      {
 743        es = *(elf_symbol_type **)(info->symbols);
 744        is_thumb = ELF_ST_TYPE (es->internal_elf_sym.st_info) ==
 745          STT_ARM_TFUNC;
 746       }
 747    }
 748
 749   info->bytes_per_chunk = 4;
 750   info->display_endian = BFD_ENDIAN_BIG;
 751
 752   /* Always fetch word aligned values.  */
 753
 754   status = (*info->read_memory_func) (pc & ~ 0x3, (bfd_byte *) &b[0], 4, info);
 755   if (status != 0)
 756     {
 757       (*info->memory_error_func) (status, pc, info);
 758       return -1;
 759     }
 760
 761   if (is_thumb)
 762     {
 763       if (pc & 0x2)
 764         {
 765           given = (b[2] << 8) | b[3];
 766
 767           status = info->read_memory_func ((pc + 4) & ~ 0x3, (bfd_byte *) b, 4, info);
 768           if (status != 0)
 769             {
 770               info->memory_error_func (status, pc + 4, info);
 771               return -1;
 772             }
 773
 774           given |= (b[0] << 24) | (b[1] << 16);
 775         }
 776       else
 777         {
 778           given = (b[0] << 8) | b[1] | (b[2] << 24) | (b[3] << 16);
 779         }
 780     }
 781   else
 782     {
 783       given = (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | (b[3]);
 784     }
 785
 786   if (is_thumb)
 787     {
 788       status = print_insn_thumb (pc, info, given);
 789     }
 790   else
 791     {
 792       status = print_insn_arm (pc, info, given);
 793     }
 794
 795   return status;
 796 }
 797
 798 int
 799 print_insn_little_arm (pc, info)
 800      bfd_vma pc;
 801      struct disassemble_info * info;
 802 {
 803   unsigned char      b[4];
 804   long               given;
 805   int                status;
 806   coff_symbol_type   *cs;
 807   elf_symbol_type    *es;
 808   int                is_thumb;
 809
 810   is_thumb = false;
 811   if (info->symbols != NULL)
 812     {
 813     if (bfd_asymbol_flavour (*info->symbols) == bfd_target_coff_flavour)
 814      {
 815        cs = coffsymbol (*info->symbols);
 816        is_thumb = (cs->native->u.syment.n_sclass == C_THUMBEXT
 817                    || cs->native->u.syment.n_sclass == C_THUMBSTAT
 818                    || cs->native->u.syment.n_sclass == C_THUMBLABEL
 819                    || cs->native->u.syment.n_sclass == C_THUMBEXTFUNC
 820                    || cs->native->u.syment.n_sclass == C_THUMBSTATFUNC);
 821
 822      }
 823     else if (bfd_asymbol_flavour (*info->symbols) == bfd_target_elf_flavour)
 824      {
 825        es = *(elf_symbol_type **)(info->symbols);
 826        is_thumb = ELF_ST_TYPE (es->internal_elf_sym.st_info) ==
 827          STT_ARM_TFUNC;
 828       }
 829    }
 830
 831   info->bytes_per_chunk = 4;
 832   info->display_endian = BFD_ENDIAN_LITTLE;
 833
 834   status = (*info->read_memory_func) (pc, (bfd_byte *) &b[0], 4, info);
 835   if (status != 0 && is_thumb)
 836     {
 837       info->bytes_per_chunk = 2;
 838
 839       status = info->read_memory_func (pc, (bfd_byte *) b, 2, info);
 840       b[3] = b[2] = 0;
 841     }
 842   if (status != 0)
 843     {
 844       (*info->memory_error_func) (status, pc, info);
 845       return -1;
 846     }
 847
 848   given = (b[0]) | (b[1] << 8) | (b[2] << 16) | (b[3] << 24);
 849
 850   if (is_thumb)
 851     {
 852       status = print_insn_thumb (pc, info, given);
 853     }
 854   else
 855     {
 856       status = print_insn_arm (pc, info, given);
 857     }
 858
 859   return status;
 860 }