opcodes/vax-dis.c

   1 /* Print VAX instructions.
   2    Copyright 1995, 1998, 2000, 2001, 2002, 2005
   3    Free Software Foundation, Inc.
   4    Contributed by Pauline Middelink <middelin@polyware.iaf.nl>
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #include <setjmp.h>
  21 #include <string.h>
  22 #include "sysdep.h"
  23 #include "opcode/vax.h"
  24 #include "dis-asm.h"
  25
  26 /* Local function prototypes */
  27 static int fetch_data PARAMS ((struct disassemble_info *, bfd_byte *));
  28 static int print_insn_arg
  29   PARAMS ((const char *, unsigned char *, bfd_vma, disassemble_info *));
  30 static int print_insn_mode
  31   PARAMS ((const char *, int, unsigned char *, bfd_vma, disassemble_info *));
  32
  33
  34 static char *reg_names[] =
  35 {
  36   "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  37   "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc"
  38 };
  39
  40 /* Definitions for the function entry mask bits.  */
  41 static char *entry_mask_bit[] =
  42 {
  43   /* Registers 0 and 1 shall not be saved, since they're used to pass back
  44      a function's result to its caller...  */
  45   "~r0~", "~r1~",
  46   /* Registers 2 .. 11 are normal registers.  */
  47   "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11",
  48   /* Registers 12 and 13 are argument and frame pointer and must not
  49      be saved by using the entry mask.  */
  50   "~ap~", "~fp~",
  51   /* Bits 14 and 15 control integer and decimal overflow.  */
  52   "IntOvfl", "DecOvfl",
  53 };
  54
  55 /* Sign-extend an (unsigned char). */
  56 #if __STDC__ == 1
  57 #define COERCE_SIGNED_CHAR(ch) ((signed char)(ch))
  58 #else
  59 #define COERCE_SIGNED_CHAR(ch) ((int)(((ch) ^ 0x80) & 0xFF) - 128)
  60 #endif
  61
  62 /* Get a 1 byte signed integer.  */
  63 #define NEXTBYTE(p)  \
  64   (p += 1, FETCH_DATA (info, p), \
  65   COERCE_SIGNED_CHAR(p[-1]))
  66
  67 /* Get a 2 byte signed integer.  */
  68 #define COERCE16(x) ((int) (((x) ^ 0x8000) - 0x8000))
  69 #define NEXTWORD(p)  \
  70   (p += 2, FETCH_DATA (info, p), \
  71    COERCE16 ((p[-1] << 8) + p[-2]))
  72
  73 /* Get a 4 byte signed integer.  */
  74 #define COERCE32(x) ((int) (((x) ^ 0x80000000) - 0x80000000))
  75 #define NEXTLONG(p)  \
  76   (p += 4, FETCH_DATA (info, p), \
  77    (COERCE32 ((((((p[-1] << 8) + p[-2]) << 8) + p[-3]) << 8) + p[-4])))
  78
  79 /* Maximum length of an instruction.  */
  80 #define MAXLEN 25
  81
  82 struct private
  83 {
  84   /* Points to first byte not fetched.  */
  85   bfd_byte * max_fetched;
  86   bfd_byte   the_buffer[MAXLEN];
  87   bfd_vma    insn_start;
  88   jmp_buf    bailout;
  89 };
  90
  91 /* Make sure that bytes from INFO->PRIVATE_DATA->BUFFER (inclusive)
  92    to ADDR (exclusive) are valid.  Returns 1 for success, longjmps
  93    on error.  */
  94 #define FETCH_DATA(info, addr) \
  95   ((addr) <= ((struct private *)(info->private_data))->max_fetched \
  96    ? 1 : fetch_data ((info), (addr)))
  97
  98 static int
  99 fetch_data (info, addr)
 100      struct disassemble_info *info;
 101      bfd_byte *addr;
 102 {
 103   int status;
 104   struct private *priv = (struct private *) info->private_data;
 105   bfd_vma start = priv->insn_start + (priv->max_fetched - priv->the_buffer);
 106
 107   status = (*info->read_memory_func) (start,
 108                                       priv->max_fetched,
 109                                       addr - priv->max_fetched,
 110                                       info);
 111   if (status != 0)
 112     {
 113       (*info->memory_error_func) (status, start, info);
 114       longjmp (priv->bailout, 1);
 115     }
 116   else
 117     priv->max_fetched = addr;
 118
 119   return 1;
 120 }
 121
 122 /* Entry mask handling.  */
 123 static unsigned int  entry_addr_occupied_slots = 0;
 124 static unsigned int  entry_addr_total_slots = 0;
 125 static bfd_vma *     entry_addr = NULL;
 126
 127 /* Parse the VAX specific disassembler options.  These contain function
 128    entry addresses, which can be useful to disassemble ROM images, since
 129    there's no symbol table.  Returns TRUE upon success, FALSE otherwise.  */
 130
 131 static bfd_boolean
 132 parse_disassembler_options (char * options)
 133 {
 134   const char * entry_switch = "entry:";
 135
 136   while ((options = strstr (options, entry_switch)))
 137     {
 138       options += strlen (entry_switch);
 139
 140       /* The greater-than part of the test below is paranoia.  */
 141       if (entry_addr_occupied_slots >= entry_addr_total_slots)
 142         {
 143           /* A guesstimate of the number of entries we will have to create.  */
 144           entry_addr_total_slots +=
 145             strlen (options) / (strlen (entry_switch) + 5);
 146
 147           entry_addr = realloc (entry_addr, sizeof (bfd_vma)
 148                                 * entry_addr_total_slots);
 149         }
 150
 151       if (entry_addr == NULL)
 152         return FALSE;
 153
 154       entry_addr[entry_addr_occupied_slots] = bfd_scan_vma (options, NULL, 0);
 155       entry_addr_occupied_slots ++;
 156     }
 157
 158   return TRUE;
 159 }
 160
 161 #if 0 /* FIXME:  Ideally the disassembler should have target specific
 162          initialisation and termination function pointers.  Then
 163          parse_disassembler_options could be the init function and
 164          free_entry_array (below) could be the termination routine.
 165          Until then there is no way for the disassembler to tell us
 166          that it has finished and that we no longer need the entry
 167          array, so this routine is suppressed for now.  It does mean
 168          that we leak memory, but only to the extent that we do not
 169          free it just before the disassembler is about to terminate
 170          anyway.  */
 171
 172 /* Free memory allocated to our entry array.  */
 173
 174 static void
 175 free_entry_array (void)
 176 {
 177   if (entry_addr)
 178     {
 179       free (entry_addr);
 180       entry_addr = NULL;
 181       entry_addr_occupied_slots = entry_addr_total_slots = 0;
 182     }
 183 }
 184 #endif
 185 /* Check if the given address is a known function entry. Either there must
 186    be a symbol of function type at this address, or the address must be
 187    a forced entry point.  The later helps in disassembling ROM images, because
 188    there's no symbol table at all.  Forced entry points can be given by
 189    supplying several -M options to objdump: -M entry:0xffbb7730.  */
 190
 191 static bfd_boolean
 192 is_function_entry (struct disassemble_info *info, bfd_vma addr)
 193 {
 194   unsigned int i;
 195
 196   /* Check if there's a BSF_FUNCTION symbol at our address.  */
 197   if (info->symbols
 198       && info->symbols[0]
 199       && (info->symbols[0]->flags & BSF_FUNCTION)
 200       && addr == bfd_asymbol_value (info->symbols[0]))
 201     return TRUE;
 202
 203   /* Check for forced function entry address.  */
 204   for (i = entry_addr_occupied_slots; i--;)
 205     if (entry_addr[i] == addr)
 206       return TRUE;
 207
 208   return FALSE;
 209 }
 210
 211 /* Print the vax instruction at address MEMADDR in debugged memory,
 212    on INFO->STREAM.  Returns length of the instruction, in bytes.  */
 213
 214 int
 215 print_insn_vax (memaddr, info)
 216      bfd_vma memaddr;
 217      disassemble_info *info;
 218 {
 219   static bfd_boolean parsed_disassembler_options = FALSE;
 220   const struct vot *votp;
 221   const char *argp;
 222   unsigned char *arg;
 223   struct private priv;
 224   bfd_byte *buffer = priv.the_buffer;
 225
 226   info->private_data = (PTR) &priv;
 227   priv.max_fetched = priv.the_buffer;
 228   priv.insn_start = memaddr;
 229
 230   if (! parsed_disassembler_options
 231       && info->disassembler_options != NULL)
 232     {
 233       parse_disassembler_options (info->disassembler_options);
 234
 235       /* To avoid repeated parsing of these options.  */
 236       parsed_disassembler_options = TRUE;
 237     }
 238
 239   if (setjmp (priv.bailout) != 0)
 240     {
 241       /* Error return.  */
 242       return -1;
 243     }
 244
 245   argp = NULL;
 246   /* Check if the info buffer has more than one byte left since
 247      the last opcode might be a single byte with no argument data.  */
 248   if (info->buffer_length - (memaddr - info->buffer_vma) > 1)
 249     {
 250       FETCH_DATA (info, buffer + 2);
 251     }
 252   else
 253     {
 254       FETCH_DATA (info, buffer + 1);
 255       buffer[1] = 0;
 256     }
 257
 258   /* Decode function entry mask.  */
 259   if (is_function_entry (info, memaddr))
 260     {
 261       int i = 0;
 262       int register_mask = buffer[1] << 8 | buffer[0];
 263
 264       (*info->fprintf_func) (info->stream, ".word 0x%04x # Entry mask: <",
 265                              register_mask);
 266
 267       for (i = 15; i >= 0; i--)
 268         if (register_mask & (1 << i))
 269           (*info->fprintf_func) (info->stream, " %s", entry_mask_bit[i]);
 270
 271       (*info->fprintf_func) (info->stream, " >");
 272
 273       return 2;
 274     }
 275
 276   for (votp = &votstrs[0]; votp->name[0]; votp++)
 277     {
 278       register vax_opcodeT opcode = votp->detail.code;
 279
 280       /* 2 byte codes match 2 buffer pos. */
 281       if ((bfd_byte) opcode == buffer[0]
 282           && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))
 283         {
 284           argp = votp->detail.args;
 285           break;
 286         }
 287     }
 288   if (argp == NULL)
 289     {
 290       /* Handle undefined instructions. */
 291       (*info->fprintf_func) (info->stream, ".word 0x%x",
 292                              (buffer[0] << 8) + buffer[1]);
 293       return 2;
 294     }
 295
 296   /* Point at first byte of argument data, and at descriptor for first
 297      argument.  */
 298   arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);
 299
 300   /* Make sure we have it in mem */
 301   FETCH_DATA (info, arg);
 302
 303   (*info->fprintf_func) (info->stream, "%s", votp->name);
 304   if (*argp)
 305     (*info->fprintf_func) (info->stream, " ");
 306
 307   while (*argp)
 308     {
 309       arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);
 310       argp += 2;
 311       if (*argp)
 312         (*info->fprintf_func) (info->stream, ",");
 313     }
 314
 315   return arg - buffer;
 316 }
 317
 318 /* Returns number of bytes "eaten" by the operand, or return -1 if an
 319    invalid operand was found, or -2 if an opcode tabel error was
 320    found. */
 321
 322 static int
 323 print_insn_arg (d, p0, addr, info)
 324      const char *d;
 325      unsigned char *p0;
 326      bfd_vma addr;              /* PC for this arg to be relative to */
 327      disassemble_info *info;
 328 {
 329   int arg_len;
 330
 331   /* check validity of addressing length */
 332   switch (d[1])
 333     {
 334     case 'b' : arg_len = 1;     break;
 335     case 'd' : arg_len = 8;     break;
 336     case 'f' : arg_len = 4;     break;
 337     case 'g' : arg_len = 8;     break;
 338     case 'h' : arg_len = 16;    break;
 339     case 'l' : arg_len = 4;     break;
 340     case 'o' : arg_len = 16;    break;
 341     case 'w' : arg_len = 2;     break;
 342     case 'q' : arg_len = 8;     break;
 343     default  : abort();
 344     }
 345
 346   /* branches have no mode byte */
 347   if (d[0] == 'b')
 348     {
 349       unsigned char *p = p0;
 350
 351       if (arg_len == 1)
 352         (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);
 353       else
 354         (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);
 355
 356       return p - p0;
 357     }
 358
 359   return print_insn_mode (d, arg_len, p0, addr, info);
 360 }
 361
 362 static int
 363 print_insn_mode (d, size, p0, addr, info)
 364      const char *d;
 365      int size;
 366      unsigned char *p0;
 367      bfd_vma addr;              /* PC for this arg to be relative to */
 368      disassemble_info *info;
 369 {
 370   unsigned char *p = p0;
 371   unsigned char mode, reg;
 372
 373   /* fetch and interpret mode byte */
 374   mode = (unsigned char) NEXTBYTE (p);
 375   reg = mode & 0xF;
 376   switch (mode & 0xF0)
 377     {
 378     case 0x00:
 379     case 0x10:
 380     case 0x20:
 381     case 0x30: /* literal mode                  $number */
 382       if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 383         (*info->fprintf_func) (info->stream, "$0x%x [%c-float]", mode, d[1]);
 384       else
 385         (*info->fprintf_func) (info->stream, "$0x%x", mode);
 386       break;
 387     case 0x40: /* index:                        base-addr[Rn] */
 388       p += print_insn_mode (d, size, p0 + 1, addr + 1, info);
 389       (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);
 390       break;
 391     case 0x50: /* register:                     Rn */
 392       (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);
 393       break;
 394     case 0x60: /* register deferred:            (Rn) */
 395       (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);
 396       break;
 397     case 0x70: /* autodecrement:                -(Rn) */
 398       (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);
 399       break;
 400     case 0x80: /* autoincrement:                (Rn)+ */
 401       if (reg == 0xF)
 402         {       /* immediate? */
 403           int i;
 404
 405           FETCH_DATA (info, p + size);
 406           (*info->fprintf_func) (info->stream, "$0x");
 407           if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 408             {
 409               int float_word;
 410
 411               float_word = p[0] | (p[1] << 8);
 412               if ((d[1] == 'd' || d[1] == 'f')
 413                   && (float_word & 0xff80) == 0x8000)
 414                 {
 415                   (*info->fprintf_func) (info->stream, "[invalid %c-float]",
 416                                          d[1]);
 417                 }
 418               else
 419                 {
 420                   for (i = 0; i < size; i++)
 421                     (*info->fprintf_func) (info->stream, "%02x",
 422                                            p[size - i - 1]);
 423                   (*info->fprintf_func) (info->stream, " [%c-float]", d[1]);
 424                 }
 425             }
 426           else
 427             {
 428               for (i = 0; i < size; i++)
 429                 (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);
 430             }
 431           p += size;
 432         }
 433       else
 434         (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);
 435       break;
 436     case 0x90: /* autoincrement deferred:       @(Rn)+ */
 437       if (reg == 0xF)
 438         (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));
 439       else
 440         (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);
 441       break;
 442     case 0xB0: /* displacement byte deferred:   *displ(Rn) */
 443       (*info->fprintf_func) (info->stream, "*");
 444     case 0xA0: /* displacement byte:            displ(Rn) */
 445       if (reg == 0xF)
 446         (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);
 447       else
 448         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),
 449                                reg_names[reg]);
 450       break;
 451     case 0xD0: /* displacement word deferred:   *displ(Rn) */
 452       (*info->fprintf_func) (info->stream, "*");
 453     case 0xC0: /* displacement word:            displ(Rn) */
 454       if (reg == 0xF)
 455         (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);
 456       else
 457         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),
 458                                reg_names[reg]);
 459       break;
 460     case 0xF0: /* displacement long deferred:   *displ(Rn) */
 461       (*info->fprintf_func) (info->stream, "*");
 462     case 0xE0: /* displacement long:            displ(Rn) */
 463       if (reg == 0xF)
 464         (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);
 465       else
 466         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),
 467                                reg_names[reg]);
 468       break;
 469     }
 470
 471   return p - p0;
 472 }