gdb/vax-tdep.c

   1 /* Print VAX instructions for GDB, the GNU debugger.
   2    Copyright 1986, 1989, 1991, 1992, 1996 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   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 "defs.h"
  21 #include "symtab.h"
  22 #include "opcode/vax.h"
  23
  24 /* Vax instructions are never longer than this.  */
  25 #define MAXLEN 62
  26
  27 /* Number of elements in the opcode table.  */
  28 #define NOPCODES (sizeof votstrs / sizeof votstrs[0])
  29
  30 static unsigned char *print_insn_arg ();
  31 \f
  32 /* Advance PC across any function entry prologue instructions
  33    to reach some "real" code.  */
  34
  35 CORE_ADDR
  36 vax_skip_prologue (pc)
  37      CORE_ADDR pc;
  38 {
  39   register int op = (unsigned char) read_memory_integer (pc, 1);
  40   if (op == 0x11)
  41     pc += 2;  /* skip brb */
  42   if (op == 0x31)
  43     pc += 3;  /* skip brw */
  44   if (op == 0xC2
  45       && ((unsigned char) read_memory_integer (pc+2, 1)) == 0x5E)
  46     pc += 3;  /* skip subl2 */
  47   if (op == 0x9E
  48       && ((unsigned char) read_memory_integer (pc+1, 1)) == 0xAE
  49       && ((unsigned char) read_memory_integer(pc+3, 1)) == 0x5E)
  50     pc += 4;  /* skip movab */
  51   if (op == 0x9E
  52       && ((unsigned char) read_memory_integer (pc+1, 1)) == 0xCE
  53       && ((unsigned char) read_memory_integer(pc+4, 1)) == 0x5E)
  54     pc += 5;  /* skip movab */
  55   if (op == 0x9E
  56       && ((unsigned char) read_memory_integer (pc+1, 1)) == 0xEE
  57       && ((unsigned char) read_memory_integer(pc+6, 1)) == 0x5E)
  58     pc += 7;  /* skip movab */
  59   return pc;
  60 }
  61
  62 /* Print the vax instruction at address MEMADDR in debugged memory,
  63    from disassembler info INFO.
  64    Returns length of the instruction, in bytes.  */
  65
  66 static int
  67 vax_print_insn (memaddr, info)
  68      CORE_ADDR memaddr;
  69      disassemble_info *info;
  70 {
  71   unsigned char buffer[MAXLEN];
  72   register int i;
  73   register unsigned char *p;
  74   register char *d;
  75
  76   int status = (*info->read_memory_func) (memaddr, buffer, MAXLEN, info);
  77   if (status != 0)
  78     {
  79       (*info->memory_error_func) (status, memaddr, info);
  80       return -1;
  81     }
  82
  83   for (i = 0; i < NOPCODES; i++)
  84     if (votstrs[i].detail.code == buffer[0]
  85         || votstrs[i].detail.code == *(unsigned short *)buffer)
  86       break;
  87
  88   /* Handle undefined instructions.  */
  89   if (i == NOPCODES)
  90     {
  91       (*info->fprintf_func) (info->stream, "0%o", buffer[0]);
  92       return 1;
  93     }
  94
  95   (*info->fprintf_func) (info->stream, "%s", votstrs[i].name);
  96
  97   /* Point at first byte of argument data,
  98      and at descriptor for first argument.  */
  99   p = buffer + 1 + (votstrs[i].detail.code >= 0x100);
 100   d = votstrs[i].detail.args;
 101
 102   if (*d)
 103     (*info->fprintf_func) (info->stream, " ");
 104
 105   while (*d)
 106     {
 107       p = print_insn_arg (d, p, memaddr + (p - buffer), info);
 108       d += 2;
 109       if (*d)
 110         (*info->fprintf_func) (info->stream, ",");
 111     }
 112   return p - buffer;
 113 }
 114
 115 static unsigned char *
 116 print_insn_arg (d, p, addr, info)
 117      char *d;
 118      register char *p;
 119      CORE_ADDR addr;
 120      disassemble_info *info;
 121 {
 122   register int regnum = *p & 0xf;
 123   float floatlitbuf;
 124
 125   if (*d == 'b')
 126     {
 127       if (d[1] == 'b')
 128         (*info->fprintf_func) (info->stream, "0x%x", addr + *p++ + 1);
 129       else
 130         {
 131           (*info->fprintf_func) (info->stream, "0x%x", addr + *(short *)p + 2);
 132           p += 2;
 133         }
 134     }
 135   else
 136     switch ((*p++ >> 4) & 0xf)
 137       {
 138       case 0:
 139       case 1:
 140       case 2:
 141       case 3:                   /* Literal mode */
 142         if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 143           {
 144             *(int *)&floatlitbuf = 0x4000 + ((p[-1] & 0x3f) << 4);
 145             (*info->fprintf_func) (info->stream, "$%f", floatlitbuf);
 146           }
 147         else
 148           (*info->fprintf_func) (info->stream, "$%d", p[-1] & 0x3f);
 149         break;
 150
 151       case 4:                   /* Indexed */
 152         p = (char *) print_insn_arg (d, p, addr + 1, info);
 153         (*info->fprintf_func) (info->stream, "[%s]", REGISTER_NAME (regnum));
 154         break;
 155
 156       case 5:                   /* Register */
 157         (*info->fprintf_func) (info->stream, REGISTER_NAME (regnum));
 158         break;
 159
 160       case 7:                   /* Autodecrement */
 161         (*info->fprintf_func) (info->stream, "-");
 162       case 6:                   /* Register deferred */
 163         (*info->fprintf_func) (info->stream, "(%s)", REGISTER_NAME (regnum));
 164         break;
 165
 166       case 9:                   /* Autoincrement deferred */
 167         (*info->fprintf_func) (info->stream, "@");
 168         if (regnum == PC_REGNUM)
 169           {
 170             (*info->fprintf_func) (info->stream, "#");
 171             info->target = *(long *)p;
 172             (*info->print_address_func) (info->target, info);
 173             p += 4;
 174             break;
 175           }
 176       case 8:                   /* Autoincrement */
 177         if (regnum == PC_REGNUM)
 178           {
 179             (*info->fprintf_func) (info->stream, "#");
 180             switch (d[1])
 181               {
 182               case 'b':
 183                 (*info->fprintf_func) (info->stream, "%d", *p++);
 184                 break;
 185
 186               case 'w':
 187                 (*info->fprintf_func) (info->stream, "%d", *(short *)p);
 188                 p += 2;
 189                 break;
 190
 191               case 'l':
 192                 (*info->fprintf_func) (info->stream, "%d", *(long *)p);
 193                 p += 4;
 194                 break;
 195
 196               case 'q':
 197                 (*info->fprintf_func) (info->stream, "0x%x%08x",
 198                                        ((long *)p)[1], ((long *)p)[0]);
 199                 p += 8;
 200                 break;
 201
 202               case 'o':
 203                 (*info->fprintf_func) (info->stream, "0x%x%08x%08x%08x",
 204                                        ((long *)p)[3], ((long *)p)[2],
 205                                        ((long *)p)[1], ((long *)p)[0]);
 206                 p += 16;
 207                 break;
 208
 209               case 'f':
 210                 if (INVALID_FLOAT (p, 4))
 211                   (*info->fprintf_func) (info->stream,
 212                                          "<<invalid float 0x%x>>",
 213                                          *(int *) p);
 214                 else
 215                   (*info->fprintf_func) (info->stream, "%f", *(float *) p);
 216                 p += 4;
 217                 break;
 218
 219               case 'd':
 220                 if (INVALID_FLOAT (p, 8))
 221                   (*info->fprintf_func) (info->stream,
 222                                          "<<invalid float 0x%x%08x>>",
 223                                          ((long *)p)[1], ((long *)p)[0]);
 224                 else
 225                   (*info->fprintf_func) (info->stream, "%f", *(double *) p);
 226                 p += 8;
 227                 break;
 228
 229               case 'g':
 230                 (*info->fprintf_func) (info->stream, "g-float");
 231                 p += 8;
 232                 break;
 233
 234               case 'h':
 235                 (*info->fprintf_func) (info->stream, "h-float");
 236                 p += 16;
 237                 break;
 238
 239               }
 240           }
 241         else
 242           (*info->fprintf_func) (info->stream, "(%s)+", REGISTER_NAME (regnum));
 243         break;
 244
 245       case 11:                  /* Byte displacement deferred */
 246         (*info->fprintf_func) (info->stream, "@");
 247       case 10:                  /* Byte displacement */
 248         if (regnum == PC_REGNUM)
 249           {
 250             info->target = addr + *p + 2;
 251             (*info->print_address_func) (info->target, info);
 252           }
 253         else
 254           (*info->fprintf_func) (info->stream, "%d(%s)", *p, REGISTER_NAME (regnum));
 255         p += 1;
 256         break;
 257
 258       case 13:                  /* Word displacement deferred */
 259         (*info->fprintf_func) (info->stream, "@");
 260       case 12:                  /* Word displacement */
 261         if (regnum == PC_REGNUM)
 262           {
 263             info->target = addr + *(short *)p + 3;
 264             (*info->print_address_func) (info->target, info);
 265           }
 266         else
 267           (*info->fprintf_func) (info->stream, "%d(%s)",
 268                                  *(short *)p, REGISTER_NAME (regnum));
 269         p += 2;
 270         break;
 271
 272       case 15:                  /* Long displacement deferred */
 273         (*info->fprintf_func) (info->stream, "@");
 274       case 14:                  /* Long displacement */
 275         if (regnum == PC_REGNUM)
 276           {
 277             info->target = addr + *(short *)p + 5;
 278             (*info->print_address_func) (info->target, info);
 279           }
 280         else
 281           (*info->fprintf_func) (info->stream, "%d(%s)",
 282                                  *(long *)p, REGISTER_NAME (regnum));
 283         p += 4;
 284       }
 285
 286   return (unsigned char *) p;
 287 }
 288
 289 void
 290 _initialize_vax_tdep ()
 291 {
 292   tm_print_insn = vax_print_insn;
 293 }