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,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include "symtab.h"
  23 #include "opcode/vax.h"
  24
  25 /* Vax instructions are never longer than this.  */
  26 #define MAXLEN 62
  27
  28 /* Number of elements in the opcode table.  */
  29 #define NOPCODES (sizeof votstrs / sizeof votstrs[0])
  30
  31 static unsigned char *print_insn_arg ();
  32 \f
  33 /* Advance PC across any function entry prologue instructions
  34    to reach some "real" code.  */
  35
  36 CORE_ADDR
  37 vax_skip_prologue (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 /* Return number of args passed to a frame.
  63    Can return -1, meaning no way to tell.  */
  64
  65 int
  66 vax_frame_num_args (struct frame_info *fi)
  67 {
  68   return (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1));
  69 }
  70
  71
  72
  73 /* Print the vax instruction at address MEMADDR in debugged memory,
  74    from disassembler info INFO.
  75    Returns length of the instruction, in bytes.  */
  76
  77 static int
  78 vax_print_insn (CORE_ADDR memaddr, disassemble_info *info)
  79 {
  80   unsigned char buffer[MAXLEN];
  81   register int i;
  82   register unsigned char *p;
  83   register char *d;
  84
  85   int status = (*info->read_memory_func) (memaddr, buffer, MAXLEN, info);
  86   if (status != 0)
  87     {
  88       (*info->memory_error_func) (status, memaddr, info);
  89       return -1;
  90     }
  91
  92   for (i = 0; i < NOPCODES; i++)
  93     if (votstrs[i].detail.code == buffer[0]
  94         || votstrs[i].detail.code == *(unsigned short *) buffer)
  95       break;
  96
  97   /* Handle undefined instructions.  */
  98   if (i == NOPCODES)
  99     {
 100       (*info->fprintf_func) (info->stream, "0%o", buffer[0]);
 101       return 1;
 102     }
 103
 104   (*info->fprintf_func) (info->stream, "%s", votstrs[i].name);
 105
 106   /* Point at first byte of argument data,
 107      and at descriptor for first argument.  */
 108   p = buffer + 1 + (votstrs[i].detail.code >= 0x100);
 109   d = votstrs[i].detail.args;
 110
 111   if (*d)
 112     (*info->fprintf_func) (info->stream, " ");
 113
 114   while (*d)
 115     {
 116       p = print_insn_arg (d, p, memaddr + (p - buffer), info);
 117       d += 2;
 118       if (*d)
 119         (*info->fprintf_func) (info->stream, ",");
 120     }
 121   return p - buffer;
 122 }
 123
 124 static unsigned char *
 125 print_insn_arg (char *d, register char *p, CORE_ADDR addr,
 126                 disassemble_info *info)
 127 {
 128   register int regnum = *p & 0xf;
 129   float floatlitbuf;
 130
 131   if (*d == 'b')
 132     {
 133       if (d[1] == 'b')
 134         (*info->fprintf_func) (info->stream, "0x%x", addr + *p++ + 1);
 135       else
 136         {
 137           (*info->fprintf_func) (info->stream, "0x%x", addr + *(short *) p + 2);
 138           p += 2;
 139         }
 140     }
 141   else
 142     switch ((*p++ >> 4) & 0xf)
 143       {
 144       case 0:
 145       case 1:
 146       case 2:
 147       case 3:                   /* Literal mode */
 148         if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 149           {
 150             *(int *) &floatlitbuf = 0x4000 + ((p[-1] & 0x3f) << 4);
 151             (*info->fprintf_func) (info->stream, "$%f", floatlitbuf);
 152           }
 153         else
 154           (*info->fprintf_func) (info->stream, "$%d", p[-1] & 0x3f);
 155         break;
 156
 157       case 4:                   /* Indexed */
 158         p = (char *) print_insn_arg (d, p, addr + 1, info);
 159         (*info->fprintf_func) (info->stream, "[%s]", REGISTER_NAME (regnum));
 160         break;
 161
 162       case 5:                   /* Register */
 163         (*info->fprintf_func) (info->stream, REGISTER_NAME (regnum));
 164         break;
 165
 166       case 7:                   /* Autodecrement */
 167         (*info->fprintf_func) (info->stream, "-");
 168       case 6:                   /* Register deferred */
 169         (*info->fprintf_func) (info->stream, "(%s)", REGISTER_NAME (regnum));
 170         break;
 171
 172       case 9:                   /* Autoincrement deferred */
 173         (*info->fprintf_func) (info->stream, "@");
 174         if (regnum == PC_REGNUM)
 175           {
 176             (*info->fprintf_func) (info->stream, "#");
 177             info->target = *(long *) p;
 178             (*info->print_address_func) (info->target, info);
 179             p += 4;
 180             break;
 181           }
 182       case 8:                   /* Autoincrement */
 183         if (regnum == PC_REGNUM)
 184           {
 185             (*info->fprintf_func) (info->stream, "#");
 186             switch (d[1])
 187               {
 188               case 'b':
 189                 (*info->fprintf_func) (info->stream, "%d", *p++);
 190                 break;
 191
 192               case 'w':
 193                 (*info->fprintf_func) (info->stream, "%d", *(short *) p);
 194                 p += 2;
 195                 break;
 196
 197               case 'l':
 198                 (*info->fprintf_func) (info->stream, "%d", *(long *) p);
 199                 p += 4;
 200                 break;
 201
 202               case 'q':
 203                 (*info->fprintf_func) (info->stream, "0x%x%08x",
 204                                        ((long *) p)[1], ((long *) p)[0]);
 205                 p += 8;
 206                 break;
 207
 208               case 'o':
 209                 (*info->fprintf_func) (info->stream, "0x%x%08x%08x%08x",
 210                                        ((long *) p)[3], ((long *) p)[2],
 211                                        ((long *) p)[1], ((long *) p)[0]);
 212                 p += 16;
 213                 break;
 214
 215               case 'f':
 216                 if (INVALID_FLOAT (p, 4))
 217                   (*info->fprintf_func) (info->stream,
 218                                          "<<invalid float 0x%x>>",
 219                                          *(int *) p);
 220                 else
 221                   (*info->fprintf_func) (info->stream, "%f", *(float *) p);
 222                 p += 4;
 223                 break;
 224
 225               case 'd':
 226                 if (INVALID_FLOAT (p, 8))
 227                   (*info->fprintf_func) (info->stream,
 228                                          "<<invalid float 0x%x%08x>>",
 229                                          ((long *) p)[1], ((long *) p)[0]);
 230                 else
 231                   (*info->fprintf_func) (info->stream, "%f", *(double *) p);
 232                 p += 8;
 233                 break;
 234
 235               case 'g':
 236                 (*info->fprintf_func) (info->stream, "g-float");
 237                 p += 8;
 238                 break;
 239
 240               case 'h':
 241                 (*info->fprintf_func) (info->stream, "h-float");
 242                 p += 16;
 243                 break;
 244
 245               }
 246           }
 247         else
 248           (*info->fprintf_func) (info->stream, "(%s)+", REGISTER_NAME (regnum));
 249         break;
 250
 251       case 11:                  /* Byte displacement deferred */
 252         (*info->fprintf_func) (info->stream, "@");
 253       case 10:                  /* Byte displacement */
 254         if (regnum == PC_REGNUM)
 255           {
 256             info->target = addr + *p + 2;
 257             (*info->print_address_func) (info->target, info);
 258           }
 259         else
 260           (*info->fprintf_func) (info->stream, "%d(%s)", *p, REGISTER_NAME (regnum));
 261         p += 1;
 262         break;
 263
 264       case 13:                  /* Word displacement deferred */
 265         (*info->fprintf_func) (info->stream, "@");
 266       case 12:                  /* Word displacement */
 267         if (regnum == PC_REGNUM)
 268           {
 269             info->target = addr + *(short *) p + 3;
 270             (*info->print_address_func) (info->target, info);
 271           }
 272         else
 273           (*info->fprintf_func) (info->stream, "%d(%s)",
 274                                  *(short *) p, REGISTER_NAME (regnum));
 275         p += 2;
 276         break;
 277
 278       case 15:                  /* Long displacement deferred */
 279         (*info->fprintf_func) (info->stream, "@");
 280       case 14:                  /* Long displacement */
 281         if (regnum == PC_REGNUM)
 282           {
 283             info->target = addr + *(short *) p + 5;
 284             (*info->print_address_func) (info->target, info);
 285           }
 286         else
 287           (*info->fprintf_func) (info->stream, "%d(%s)",
 288                                  *(long *) p, REGISTER_NAME (regnum));
 289         p += 4;
 290       }
 291
 292   return (unsigned char *) p;
 293 }
 294
 295 void
 296 _initialize_vax_tdep (void)
 297 {
 298   tm_print_insn = vax_print_insn;
 299 }