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 "sysdep.h"
  21 #include "opcode/vax.h"
  22 #include "dis-asm.h"
  23
  24 /* Local function prototypes */
  25 static int fetch_data PARAMS ((struct disassemble_info *, bfd_byte *));
  26 static int print_insn_arg
  27   PARAMS ((const char *, unsigned char *, bfd_vma, disassemble_info *));
  28 static int print_insn_mode
  29   PARAMS ((const char *, int, unsigned char *, bfd_vma, disassemble_info *));
  30
  31
  32 static char *reg_names[] =
  33 {
  34   "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  35   "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc"
  36 };
  37
  38 /* Definitions for the function entry mask bits.  */
  39 static char *entry_mask_bit[] =
  40 {
  41   /* Registers 0 and 1 shall not be saved, since they're used to pass back
  42      a function's result to its caller...  */
  43   "~r0~", "~r1~",
  44   /* Registers 2 .. 11 are normal registers.  */
  45   "r2", "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10", "r11",
  46   /* Registers 12 and 13 are argument and frame pointer and must not
  47      be saved by using the entry mask.  */
  48   "~ap~", "~fp~",
  49   /* Bits 14 and 15 control integer and decimal overflow.  */
  50   "IntOvfl", "DecOvfl",
  51 };
  52
  53 /* Sign-extend an (unsigned char). */
  54 #if __STDC__ == 1
  55 #define COERCE_SIGNED_CHAR(ch) ((signed char)(ch))
  56 #else
  57 #define COERCE_SIGNED_CHAR(ch) ((int)(((ch) ^ 0x80) & 0xFF) - 128)
  58 #endif
  59
  60 /* Get a 1 byte signed integer.  */
  61 #define NEXTBYTE(p)  \
  62   (p += 1, FETCH_DATA (info, p), \
  63   COERCE_SIGNED_CHAR(p[-1]))
  64
  65 /* Get a 2 byte signed integer.  */
  66 #define COERCE16(x) ((int) (((x) ^ 0x8000) - 0x8000))
  67 #define NEXTWORD(p)  \
  68   (p += 2, FETCH_DATA (info, p), \
  69    COERCE16 ((p[-1] << 8) + p[-2]))
  70
  71 /* Get a 4 byte signed integer.  */
  72 #define COERCE32(x) ((int) (((x) ^ 0x80000000) - 0x80000000))
  73 #define NEXTLONG(p)  \
  74   (p += 4, FETCH_DATA (info, p), \
  75    (COERCE32 ((((((p[-1] << 8) + p[-2]) << 8) + p[-3]) << 8) + p[-4])))
  76
  77 /* Maximum length of an instruction.  */
  78 #define MAXLEN 25
  79
  80 #include <setjmp.h>
  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 /* Print the vax instruction at address MEMADDR in debugged memory,
 123    on INFO->STREAM.  Returns length of the instruction, in bytes.  */
 124
 125 int
 126 print_insn_vax (memaddr, info)
 127      bfd_vma memaddr;
 128      disassemble_info *info;
 129 {
 130   const struct vot *votp;
 131   const char *argp;
 132   unsigned char *arg;
 133   struct private priv;
 134   bfd_byte *buffer = priv.the_buffer;
 135
 136   info->private_data = (PTR) &priv;
 137   priv.max_fetched = priv.the_buffer;
 138   priv.insn_start = memaddr;
 139
 140   if (setjmp (priv.bailout) != 0)
 141     {
 142       /* Error return.  */
 143       return -1;
 144     }
 145
 146   argp = NULL;
 147   /* Check if the info buffer has more than one byte left since
 148      the last opcode might be a single byte with no argument data.  */
 149   if (info->buffer_length - (memaddr - info->buffer_vma) > 1)
 150     {
 151       FETCH_DATA (info, buffer + 2);
 152     }
 153   else
 154     {
 155       FETCH_DATA (info, buffer + 1);
 156       buffer[1] = 0;
 157     }
 158
 159   /* Decode function entry mask.  */
 160   if (info->symbols
 161       && info->symbols[0]
 162       && (info->symbols[0]->flags & BSF_FUNCTION)
 163       && memaddr == bfd_asymbol_value (info->symbols[0]))
 164     {
 165       int i = 0;
 166       int register_mask = buffer[1] << 8 | buffer[0];
 167
 168       (*info->fprintf_func) (info->stream, ".word 0x%04x # Entry mask: <",
 169                              register_mask);
 170
 171       for (i = 15; i >= 0; i--)
 172         if (register_mask & (1 << i))
 173           (*info->fprintf_func) (info->stream, " %s", entry_mask_bit[i]);
 174
 175       (*info->fprintf_func) (info->stream, " >");
 176
 177       return 2;
 178     }
 179
 180   for (votp = &votstrs[0]; votp->name[0]; votp++)
 181     {
 182       register vax_opcodeT opcode = votp->detail.code;
 183
 184       /* 2 byte codes match 2 buffer pos. */
 185       if ((bfd_byte) opcode == buffer[0]
 186           && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))
 187         {
 188           argp = votp->detail.args;
 189           break;
 190         }
 191     }
 192   if (argp == NULL)
 193     {
 194       /* Handle undefined instructions. */
 195       (*info->fprintf_func) (info->stream, ".word 0x%x",
 196                              (buffer[0] << 8) + buffer[1]);
 197       return 2;
 198     }
 199
 200   /* Point at first byte of argument data, and at descriptor for first
 201      argument.  */
 202   arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);
 203
 204   /* Make sure we have it in mem */
 205   FETCH_DATA (info, arg);
 206
 207   (*info->fprintf_func) (info->stream, "%s", votp->name);
 208   if (*argp)
 209     (*info->fprintf_func) (info->stream, " ");
 210
 211   while (*argp)
 212     {
 213       arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);
 214       argp += 2;
 215       if (*argp)
 216         (*info->fprintf_func) (info->stream, ",");
 217     }
 218
 219   return arg - buffer;
 220 }
 221
 222 /* Returns number of bytes "eaten" by the operand, or return -1 if an
 223    invalid operand was found, or -2 if an opcode tabel error was
 224    found. */
 225
 226 static int
 227 print_insn_arg (d, p0, addr, info)
 228      const char *d;
 229      unsigned char *p0;
 230      bfd_vma addr;              /* PC for this arg to be relative to */
 231      disassemble_info *info;
 232 {
 233   int arg_len;
 234
 235   /* check validity of addressing length */
 236   switch (d[1])
 237     {
 238     case 'b' : arg_len = 1;     break;
 239     case 'd' : arg_len = 8;     break;
 240     case 'f' : arg_len = 4;     break;
 241     case 'g' : arg_len = 8;     break;
 242     case 'h' : arg_len = 16;    break;
 243     case 'l' : arg_len = 4;     break;
 244     case 'o' : arg_len = 16;    break;
 245     case 'w' : arg_len = 2;     break;
 246     case 'q' : arg_len = 8;     break;
 247     default  : abort();
 248     }
 249
 250   /* branches have no mode byte */
 251   if (d[0] == 'b')
 252     {
 253       unsigned char *p = p0;
 254
 255       if (arg_len == 1)
 256         (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);
 257       else
 258         (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);
 259
 260       return p - p0;
 261     }
 262
 263   return print_insn_mode (d, arg_len, p0, addr, info);
 264 }
 265
 266 static int
 267 print_insn_mode (d, size, p0, addr, info)
 268      const char *d;
 269      int size;
 270      unsigned char *p0;
 271      bfd_vma addr;              /* PC for this arg to be relative to */
 272      disassemble_info *info;
 273 {
 274   unsigned char *p = p0;
 275   unsigned char mode, reg;
 276
 277   /* fetch and interpret mode byte */
 278   mode = (unsigned char) NEXTBYTE (p);
 279   reg = mode & 0xF;
 280   switch (mode & 0xF0)
 281     {
 282     case 0x00:
 283     case 0x10:
 284     case 0x20:
 285     case 0x30: /* literal mode                  $number */
 286       if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 287         (*info->fprintf_func) (info->stream, "$0x%x [%c-float]", mode, d[1]);
 288       else
 289         (*info->fprintf_func) (info->stream, "$0x%x", mode);
 290       break;
 291     case 0x40: /* index:                        base-addr[Rn] */
 292       p += print_insn_mode (d, size, p0 + 1, addr + 1, info);
 293       (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);
 294       break;
 295     case 0x50: /* register:                     Rn */
 296       (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);
 297       break;
 298     case 0x60: /* register deferred:            (Rn) */
 299       (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);
 300       break;
 301     case 0x70: /* autodecrement:                -(Rn) */
 302       (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);
 303       break;
 304     case 0x80: /* autoincrement:                (Rn)+ */
 305       if (reg == 0xF)
 306         {       /* immediate? */
 307           int i;
 308
 309           FETCH_DATA (info, p + size);
 310           (*info->fprintf_func) (info->stream, "$0x");
 311           if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 312             {
 313               int float_word;
 314
 315               float_word = p[0] | (p[1] << 8);
 316               if ((d[1] == 'd' || d[1] == 'f')
 317                   && (float_word & 0xff80) == 0x8000)
 318                 {
 319                   (*info->fprintf_func) (info->stream, "[invalid %c-float]",
 320                                          d[1]);
 321                 }
 322               else
 323                 {
 324                   for (i = 0; i < size; i++)
 325                     (*info->fprintf_func) (info->stream, "%02x",
 326                                            p[size - i - 1]);
 327                   (*info->fprintf_func) (info->stream, " [%c-float]", d[1]);
 328                 }
 329             }
 330           else
 331             {
 332               for (i = 0; i < size; i++)
 333                 (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);
 334             }
 335           p += size;
 336         }
 337       else
 338         (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);
 339       break;
 340     case 0x90: /* autoincrement deferred:       @(Rn)+ */
 341       if (reg == 0xF)
 342         (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));
 343       else
 344         (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);
 345       break;
 346     case 0xB0: /* displacement byte deferred:   *displ(Rn) */
 347       (*info->fprintf_func) (info->stream, "*");
 348     case 0xA0: /* displacement byte:            displ(Rn) */
 349       if (reg == 0xF)
 350         (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);
 351       else
 352         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),
 353                                reg_names[reg]);
 354       break;
 355     case 0xD0: /* displacement word deferred:   *displ(Rn) */
 356       (*info->fprintf_func) (info->stream, "*");
 357     case 0xC0: /* displacement word:            displ(Rn) */
 358       if (reg == 0xF)
 359         (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);
 360       else
 361         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),
 362                                reg_names[reg]);
 363       break;
 364     case 0xF0: /* displacement long deferred:   *displ(Rn) */
 365       (*info->fprintf_func) (info->stream, "*");
 366     case 0xE0: /* displacement long:            displ(Rn) */
 367       if (reg == 0xF)
 368         (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);
 369       else
 370         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),
 371                                reg_names[reg]);
 372       break;
 373     }
 374
 375   return p - p0;
 376 }