opcodes/vax-dis.c

   1 /* Print VAX instructions.
   2    Copyright 1995, 1998, 2000, 2001 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 fetch_data PARAMS ((struct disassemble_info *, bfd_byte *));
  25 static int print_insn_arg
  26   PARAMS ((const char *, unsigned char *, bfd_vma, disassemble_info *));
  27 static int print_insn_mode
  28   PARAMS ((int, unsigned char *, bfd_vma, disassemble_info *));
  29
  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;
 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
 124   if (setjmp (priv.bailout) != 0)
 125     {
 126       /* Error return.  */
 127       return -1;
 128     }
 129
 130   argp = NULL;
 131   /* Check if the info buffer has more than one byte left since
 132      the last opcode might be a single byte with no argument data.  */
 133   if (info->buffer_length - (memaddr - info->buffer_vma) > 1)
 134     {
 135       FETCH_DATA (info, buffer + 2);
 136     }
 137   else
 138     {
 139       FETCH_DATA (info, buffer + 1);
 140       buffer[1] = 0;
 141     }
 142
 143   for (votp = &votstrs[0]; votp->name[0]; votp++)
 144     {
 145       register vax_opcodeT opcode = votp->detail.code;
 146
 147       /* 2 byte codes match 2 buffer pos. */
 148       if ((bfd_byte) opcode == buffer[0]
 149           && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))
 150         {
 151           argp = votp->detail.args;
 152           break;
 153         }
 154     }
 155   if (argp == NULL)
 156     {
 157       /* Handle undefined instructions. */
 158       (*info->fprintf_func) (info->stream, ".word 0x%x",
 159                              (buffer[0] << 8) + buffer[1]);
 160       return 2;
 161     }
 162
 163   /* Point at first byte of argument data, and at descriptor for first
 164      argument.  */
 165   arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);
 166
 167   /* Make sure we have it in mem */
 168   FETCH_DATA (info, arg);
 169
 170   (*info->fprintf_func) (info->stream, "%s", votp->name);
 171   if (*argp)
 172     (*info->fprintf_func) (info->stream, " ");
 173
 174   while (*argp)
 175     {
 176       arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);
 177       argp += 2;
 178       if (*argp)
 179         (*info->fprintf_func) (info->stream, ",");
 180     }
 181
 182   return arg - buffer;
 183 }
 184
 185 /* Returns number of bytes "eaten" by the operand, or return -1 if an
 186    invalid operand was found, or -2 if an opcode tabel error was
 187    found. */
 188
 189 static int
 190 print_insn_arg (d, p0, addr, info)
 191      const char *d;
 192      unsigned char *p0;
 193      bfd_vma addr;              /* PC for this arg to be relative to */
 194      disassemble_info *info;
 195 {
 196   int arg_len;
 197
 198   /* check validity of addressing length */
 199   switch (d[1])
 200     {
 201     case 'b' : arg_len = 1;     break;
 202     case 'd' : arg_len = 8;     break;
 203     case 'f' : arg_len = 4;     break;
 204     case 'g' : arg_len = 8;     break;
 205     case 'h' : arg_len = 16;    break;
 206     case 'l' : arg_len = 4;     break;
 207     case 'o' : arg_len = 16;    break;
 208     case 'w' : arg_len = 2;     break;
 209     case 'q' : arg_len = 8;     break;
 210     default  : abort();
 211     }
 212
 213   /* branches have no mode byte */
 214   if (d[0] == 'b')
 215     {
 216       unsigned char *p = p0;
 217
 218       if (arg_len == 1)
 219         (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);
 220       else
 221         (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);
 222
 223       return p - p0;
 224     }
 225
 226   return print_insn_mode (arg_len, p0, addr, info);
 227 }
 228
 229 static int
 230 print_insn_mode (size, p0, addr, info)
 231      int size;
 232      unsigned char *p0;
 233      bfd_vma addr;              /* PC for this arg to be relative to */
 234      disassemble_info *info;
 235 {
 236   unsigned char *p = p0;
 237   unsigned char mode, reg;
 238
 239   /* fetch and interpret mode byte */
 240   mode = (unsigned char) NEXTBYTE (p);
 241   reg = mode & 0xF;
 242   switch (mode & 0xF0)
 243     {
 244     case 0x00:
 245     case 0x10:
 246     case 0x20:
 247     case 0x30: /* literal mode                  $number */
 248       (*info->fprintf_func) (info->stream, "$0x%x", mode);
 249       break;
 250     case 0x40: /* index:                        base-addr[Rn] */
 251       p += print_insn_mode (size, p0 + 1, addr + 1, info);
 252       (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);
 253       break;
 254     case 0x50: /* register:                     Rn */
 255       (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);
 256       break;
 257     case 0x60: /* register deferred:            (Rn) */
 258       (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);
 259       break;
 260     case 0x70: /* autodecrement:                -(Rn) */
 261       (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);
 262       break;
 263     case 0x80: /* autoincrement:                (Rn)+ */
 264       if (reg == 0xF)
 265         {       /* immediate? */
 266           int i;
 267
 268           FETCH_DATA (info, p + size);
 269           (*info->fprintf_func) (info->stream, "$0x");
 270           for (i = 0; i < size; i++)
 271             (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);
 272           p += size;
 273         }
 274       else
 275         (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);
 276       break;
 277     case 0x90: /* autoincrement deferred:       @(Rn)+ */
 278       if (reg == 0xF)
 279         (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));
 280       else
 281         (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);
 282       break;
 283     case 0xB0: /* displacement byte deferred:   *displ(Rn) */
 284       (*info->fprintf_func) (info->stream, "*");
 285     case 0xA0: /* displacement byte:            displ(Rn) */
 286       if (reg == 0xF)
 287         (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);
 288       else
 289         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),
 290                                reg_names[reg]);
 291       break;
 292     case 0xD0: /* displacement word deferred:   *displ(Rn) */
 293       (*info->fprintf_func) (info->stream, "*");
 294     case 0xC0: /* displacement word:            displ(Rn) */
 295       if (reg == 0xF)
 296         (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);
 297       else
 298         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),
 299                                reg_names[reg]);
 300       break;
 301     case 0xF0: /* displacement long deferred:   *displ(Rn) */
 302       (*info->fprintf_func) (info->stream, "*");
 303     case 0xE0: /* displacement long:            displ(Rn) */
 304       if (reg == 0xF)
 305         (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);
 306       else
 307         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),
 308                                reg_names[reg]);
 309       break;
 310     }
 311
 312   return p - p0;
 313 }