opcodes/vax-dis.c

   1 /* Print VAX instructions.
   2    Copyright (C) 1995, 1998 Free Software Foundation, Inc.
   3    Contributed by Pauline Middelink <middelin@polyware.iaf.nl>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #include "sysdep.h"
  20 #include "opcode/vax.h"
  21 #include "dis-asm.h"
  22
  23 /* Local function prototypes */
  24 static int
  25 print_insn_arg PARAMS ((const char *, unsigned char *, bfd_vma,
  26                         disassemble_info *));
  27
  28 static int
  29 print_insn_mode PARAMS ((int, unsigned char *, bfd_vma, disassemble_info *));
  30
  31 static char *reg_names[] =
  32 {
  33   "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  34   "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc"
  35 };
  36
  37 /* Sign-extend an (unsigned char). */
  38 #if __STDC__ == 1
  39 #define COERCE_SIGNED_CHAR(ch) ((signed char)(ch))
  40 #else
  41 #define COERCE_SIGNED_CHAR(ch) ((int)(((ch) ^ 0x80) & 0xFF) - 128)
  42 #endif
  43
  44 /* Get a 1 byte signed integer.  */
  45 #define NEXTBYTE(p)  \
  46   (p += 1, FETCH_DATA (info, p), \
  47   COERCE_SIGNED_CHAR(p[-1]))
  48
  49 /* Get a 2 byte signed integer.  */
  50 #define COERCE16(x) ((int) (((x) ^ 0x8000) - 0x8000))
  51 #define NEXTWORD(p)  \
  52   (p += 2, FETCH_DATA (info, p), \
  53    COERCE16 ((p[-1] << 8) + p[-2]))
  54
  55 /* Get a 4 byte signed integer.  */
  56 #define COERCE32(x) ((int) (((x) ^ 0x80000000) - 0x80000000))
  57 #define NEXTLONG(p)  \
  58   (p += 4, FETCH_DATA (info, p), \
  59    (COERCE32 ((((((p[-1] << 8) + p[-2]) << 8) + p[-3]) << 8) + p[-4])))
  60
  61 /* Maximum length of an instruction.  */
  62 #define MAXLEN 25
  63
  64 #include <setjmp.h>
  65
  66 struct private
  67 {
  68   /* Points to first byte not fetched.  */
  69   bfd_byte *max_fetched;
  70   bfd_byte the_buffer[MAXLEN];
  71   bfd_vma insn_start;
  72   jmp_buf bailout;
  73 };
  74
  75 /* Make sure that bytes from INFO->PRIVATE_DATA->BUFFER (inclusive)
  76    to ADDR (exclusive) are valid.  Returns 1 for success, longjmps
  77    on error.  */
  78 #define FETCH_DATA(info, addr) \
  79   ((addr) <= ((struct private *)(info->private_data))->max_fetched \
  80    ? 1 : fetch_data ((info), (addr)))
  81
  82 static int
  83 fetch_data (info, addr)
  84      struct disassemble_info *info;
  85      bfd_byte *addr;
  86 {
  87   int status;
  88   struct private *priv = (struct private *) info->private_data;
  89   bfd_vma start = priv->insn_start + (priv->max_fetched - priv->the_buffer);
  90
  91   status = (*info->read_memory_func) (start,
  92                                       priv->max_fetched,
  93                                       addr - priv->max_fetched,
  94                                       info);
  95   if (status != 0)
  96     {
  97       (*info->memory_error_func) (status, start, info);
  98       longjmp (priv->bailout, 1);
  99     }
 100   else
 101     priv->max_fetched = addr;
 102
 103   return 1;
 104 }
 105
 106 /* Print the vax instruction at address MEMADDR in debugged memory,
 107    on INFO->STREAM.  Returns length of the instruction, in bytes.  */
 108
 109 int
 110 print_insn_vax (memaddr, info)
 111      bfd_vma memaddr;
 112      disassemble_info *info;
 113 {
 114   const struct vot *votp;
 115   const char *argp = NULL;
 116   unsigned char *arg;
 117   struct private priv;
 118   bfd_byte *buffer = priv.the_buffer;
 119
 120   info->private_data = (PTR) &priv;
 121   priv.max_fetched = priv.the_buffer;
 122   priv.insn_start = memaddr;
 123   if (setjmp (priv.bailout) != 0)
 124     {
 125       /* Error return.  */
 126       return -1;
 127     }
 128
 129   FETCH_DATA (info, buffer + 2);
 130   for (votp = &votstrs[0]; votp->name[0]; votp++)
 131     {
 132       register vax_opcodeT opcode = votp->detail.code;
 133
 134       /* 2 byte codes match 2 buffer pos. */
 135       if ((bfd_byte) opcode == buffer[0]
 136           && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))
 137         {
 138           argp = votp->detail.args;
 139           break;
 140         }
 141     }
 142   if (argp == NULL)
 143     {
 144       /* Handle undefined instructions. */
 145       (*info->fprintf_func) (info->stream, ".word 0x%x",
 146                              (buffer[0] << 8) + buffer[1]);
 147       return 2;
 148     }
 149
 150   /* Point at first byte of argument data, and at descriptor for first
 151      argument.  */
 152   arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);
 153
 154   /* Make sure we have it in mem */
 155   FETCH_DATA (info, arg);
 156
 157   (*info->fprintf_func) (info->stream, "%s", votp->name);
 158   if (*argp)
 159     (*info->fprintf_func) (info->stream, " ");
 160
 161   while (*argp)
 162     {
 163       arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);
 164       argp += 2;
 165       if (*argp)
 166         (*info->fprintf_func) (info->stream, ",");
 167     }
 168
 169   return arg - buffer;
 170 }
 171
 172 /* Returns number of bytes "eaten" by the operand, or return -1 if an
 173    invalid operand was found, or -2 if an opcode tabel error was
 174    found. */
 175
 176 static int
 177 print_insn_arg (d, p0, addr, info)
 178      const char *d;
 179      unsigned char *p0;
 180      bfd_vma addr;              /* PC for this arg to be relative to */
 181      disassemble_info *info;
 182 {
 183   int arg_len;
 184
 185   /* check validity of addressing length */
 186   switch (d[1])
 187     {
 188     case 'b' : arg_len = 1;     break;
 189     case 'd' : arg_len = 8;     break;
 190     case 'f' : arg_len = 4;     break;
 191     case 'g' : arg_len = 8;     break;
 192     case 'h' : arg_len = 16;    break;
 193     case 'l' : arg_len = 4;     break;
 194     case 'o' : arg_len = 16;    break;
 195     case 'w' : arg_len = 2;     break;
 196     case 'q' : arg_len = 8;     break;
 197     default  : abort();
 198     }
 199
 200   /* branches have no mode byte */
 201   if (d[0] == 'b')
 202     {
 203       unsigned char *p = p0;
 204
 205       if (arg_len == 1)
 206         (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);
 207       else
 208         (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);
 209
 210       return p - p0;
 211     }
 212
 213   return print_insn_mode (arg_len, p0, addr, info);
 214 }
 215
 216 static int
 217 print_insn_mode (size, p0, addr, info)
 218      int size;
 219      unsigned char *p0;
 220      bfd_vma addr;              /* PC for this arg to be relative to */
 221      disassemble_info *info;
 222 {
 223   unsigned char *p = p0;
 224   unsigned char mode, reg;
 225
 226   /* fetch and interpret mode byte */
 227   mode = (unsigned char) NEXTBYTE (p);
 228   reg = mode & 0xF;
 229   switch (mode & 0xF0)
 230     {
 231     case 0x00:
 232     case 0x10:
 233     case 0x20:
 234     case 0x30: /* literal mode                  $number */
 235       (*info->fprintf_func) (info->stream, "$0x%x", mode);
 236       break;
 237     case 0x40: /* index:                        base-addr[Rn] */
 238       p += print_insn_mode (size, p0 + 1, addr + 1, info);
 239       (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);
 240       break;
 241     case 0x50: /* register:                     Rn */
 242       (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);
 243       break;
 244     case 0x60: /* register deferred:            (Rn) */
 245       (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);
 246       break;
 247     case 0x70: /* autodecrement:                -(Rn) */
 248       (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);
 249       break;
 250     case 0x80: /* autoincrement:                (Rn)+ */
 251       if (reg == 0xF)
 252         {       /* immediate? */
 253           int i;
 254
 255           FETCH_DATA (info, p + size);
 256           (*info->fprintf_func) (info->stream, "$0x");
 257           for (i = 0; i < size; i++)
 258             (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);
 259           p += size;
 260         }
 261       else
 262         (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);
 263       break;
 264     case 0x90: /* autoincrement deferred:       @(Rn)+ */
 265       if (reg == 0xF)
 266         (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));
 267       else
 268         (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);
 269       break;
 270     case 0xB0: /* displacement byte deferred:   *displ(Rn) */
 271       (*info->fprintf_func) (info->stream, "*");
 272     case 0xA0: /* displacement byte:            displ(Rn) */
 273       if (reg == 0xF)
 274         (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);
 275       else
 276         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),
 277                                reg_names[reg]);
 278       break;
 279     case 0xD0: /* displacement word deferred:   *displ(Rn) */
 280       (*info->fprintf_func) (info->stream, "*");
 281     case 0xC0: /* displacement word:            displ(Rn) */
 282       if (reg == 0xF)
 283         (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);
 284       else
 285         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),
 286                                reg_names[reg]);
 287       break;
 288     case 0xF0: /* displacement long deferred:   *displ(Rn) */
 289       (*info->fprintf_func) (info->stream, "*");
 290     case 0xE0: /* displacement long:            displ(Rn) */
 291       if (reg == 0xF)
 292         (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);
 293       else
 294         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),
 295                                reg_names[reg]);
 296       break;
 297     }
 298
 299   return p - p0;
 300 }