gdb/vax-tdep.c

   1 /* Print VAX instructions for GDB, the GNU debugger.
   2    Copyright 1986, 1989, 1991, 1992, 1995, 1996, 1998, 1999, 2000
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "symtab.h"
  24 #include "opcode/vax.h"
  25 #include "gdbcore.h"
  26 #include "frame.h"
  27 #include "value.h"
  28
  29 /* Vax instructions are never longer than this.  */
  30 #define MAXLEN 62
  31
  32 /* Number of elements in the opcode table.  */
  33 #define NOPCODES (sizeof votstrs / sizeof votstrs[0])
  34
  35 static unsigned char *print_insn_arg ();
  36 \f
  37 /* Advance PC across any function entry prologue instructions
  38    to reach some "real" code.  */
  39
  40 CORE_ADDR
  41 vax_skip_prologue (CORE_ADDR pc)
  42 {
  43   register int op = (unsigned char) read_memory_integer (pc, 1);
  44   if (op == 0x11)
  45     pc += 2;                    /* skip brb */
  46   if (op == 0x31)
  47     pc += 3;                    /* skip brw */
  48   if (op == 0xC2
  49       && ((unsigned char) read_memory_integer (pc + 2, 1)) == 0x5E)
  50     pc += 3;                    /* skip subl2 */
  51   if (op == 0x9E
  52       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xAE
  53       && ((unsigned char) read_memory_integer (pc + 3, 1)) == 0x5E)
  54     pc += 4;                    /* skip movab */
  55   if (op == 0x9E
  56       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xCE
  57       && ((unsigned char) read_memory_integer (pc + 4, 1)) == 0x5E)
  58     pc += 5;                    /* skip movab */
  59   if (op == 0x9E
  60       && ((unsigned char) read_memory_integer (pc + 1, 1)) == 0xEE
  61       && ((unsigned char) read_memory_integer (pc + 6, 1)) == 0x5E)
  62     pc += 7;                    /* skip movab */
  63   return pc;
  64 }
  65
  66 /* Return number of args passed to a frame.
  67    Can return -1, meaning no way to tell.  */
  68
  69 int
  70 vax_frame_num_args (struct frame_info *fi)
  71 {
  72   return (0xff & read_memory_integer (FRAME_ARGS_ADDRESS (fi), 1));
  73 }
  74
  75
  76
  77 /* Print the vax instruction at address MEMADDR in debugged memory,
  78    from disassembler info INFO.
  79    Returns length of the instruction, in bytes.  */
  80
  81 static int
  82 vax_print_insn (CORE_ADDR memaddr, disassemble_info *info)
  83 {
  84   unsigned char buffer[MAXLEN];
  85   register int i;
  86   register unsigned char *p;
  87   const char *d;
  88
  89   int status = (*info->read_memory_func) (memaddr, buffer, MAXLEN, info);
  90   if (status != 0)
  91     {
  92       (*info->memory_error_func) (status, memaddr, info);
  93       return -1;
  94     }
  95
  96   for (i = 0; i < NOPCODES; i++)
  97     if (votstrs[i].detail.code == buffer[0]
  98         || votstrs[i].detail.code == *(unsigned short *) buffer)
  99       break;
 100
 101   /* Handle undefined instructions.  */
 102   if (i == NOPCODES)
 103     {
 104       (*info->fprintf_func) (info->stream, "0%o", buffer[0]);
 105       return 1;
 106     }
 107
 108   (*info->fprintf_func) (info->stream, "%s", votstrs[i].name);
 109
 110   /* Point at first byte of argument data,
 111      and at descriptor for first argument.  */
 112   p = buffer + 1 + (votstrs[i].detail.code >= 0x100);
 113   d = votstrs[i].detail.args;
 114
 115   if (*d)
 116     (*info->fprintf_func) (info->stream, " ");
 117
 118   while (*d)
 119     {
 120       p = print_insn_arg (d, p, memaddr + (p - buffer), info);
 121       d += 2;
 122       if (*d)
 123         (*info->fprintf_func) (info->stream, ",");
 124     }
 125   return p - buffer;
 126 }
 127
 128 static unsigned char *
 129 print_insn_arg (char *d, register char *p, CORE_ADDR addr,
 130                 disassemble_info *info)
 131 {
 132   register int regnum = *p & 0xf;
 133   float floatlitbuf;
 134
 135   if (*d == 'b')
 136     {
 137       if (d[1] == 'b')
 138         (*info->fprintf_func) (info->stream, "0x%x", addr + *p++ + 1);
 139       else
 140         {
 141           (*info->fprintf_func) (info->stream, "0x%x", addr + *(short *) p + 2);
 142           p += 2;
 143         }
 144     }
 145   else
 146     switch ((*p++ >> 4) & 0xf)
 147       {
 148       case 0:
 149       case 1:
 150       case 2:
 151       case 3:                   /* Literal mode */
 152         if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
 153           {
 154             *(int *) &floatlitbuf = 0x4000 + ((p[-1] & 0x3f) << 4);
 155             (*info->fprintf_func) (info->stream, "$%f", floatlitbuf);
 156           }
 157         else
 158           (*info->fprintf_func) (info->stream, "$%d", p[-1] & 0x3f);
 159         break;
 160
 161       case 4:                   /* Indexed */
 162         p = (char *) print_insn_arg (d, p, addr + 1, info);
 163         (*info->fprintf_func) (info->stream, "[%s]", REGISTER_NAME (regnum));
 164         break;
 165
 166       case 5:                   /* Register */
 167         (*info->fprintf_func) (info->stream, REGISTER_NAME (regnum));
 168         break;
 169
 170       case 7:                   /* Autodecrement */
 171         (*info->fprintf_func) (info->stream, "-");
 172       case 6:                   /* Register deferred */
 173         (*info->fprintf_func) (info->stream, "(%s)", REGISTER_NAME (regnum));
 174         break;
 175
 176       case 9:                   /* Autoincrement deferred */
 177         (*info->fprintf_func) (info->stream, "@");
 178         if (regnum == PC_REGNUM)
 179           {
 180             (*info->fprintf_func) (info->stream, "#");
 181             info->target = *(long *) p;
 182             (*info->print_address_func) (info->target, info);
 183             p += 4;
 184             break;
 185           }
 186       case 8:                   /* Autoincrement */
 187         if (regnum == PC_REGNUM)
 188           {
 189             (*info->fprintf_func) (info->stream, "#");
 190             switch (d[1])
 191               {
 192               case 'b':
 193                 (*info->fprintf_func) (info->stream, "%d", *p++);
 194                 break;
 195
 196               case 'w':
 197                 (*info->fprintf_func) (info->stream, "%d", *(short *) p);
 198                 p += 2;
 199                 break;
 200
 201               case 'l':
 202                 (*info->fprintf_func) (info->stream, "%d", *(long *) p);
 203                 p += 4;
 204                 break;
 205
 206               case 'q':
 207                 (*info->fprintf_func) (info->stream, "0x%x%08x",
 208                                        ((long *) p)[1], ((long *) p)[0]);
 209                 p += 8;
 210                 break;
 211
 212               case 'o':
 213                 (*info->fprintf_func) (info->stream, "0x%x%08x%08x%08x",
 214                                        ((long *) p)[3], ((long *) p)[2],
 215                                        ((long *) p)[1], ((long *) p)[0]);
 216                 p += 16;
 217                 break;
 218
 219               case 'f':
 220                 if (INVALID_FLOAT (p, 4))
 221                   (*info->fprintf_func) (info->stream,
 222                                          "<<invalid float 0x%x>>",
 223                                          *(int *) p);
 224                 else
 225                   (*info->fprintf_func) (info->stream, "%f", *(float *) p);
 226                 p += 4;
 227                 break;
 228
 229               case 'd':
 230                 if (INVALID_FLOAT (p, 8))
 231                   (*info->fprintf_func) (info->stream,
 232                                          "<<invalid float 0x%x%08x>>",
 233                                          ((long *) p)[1], ((long *) p)[0]);
 234                 else
 235                   (*info->fprintf_func) (info->stream, "%f", *(double *) p);
 236                 p += 8;
 237                 break;
 238
 239               case 'g':
 240                 (*info->fprintf_func) (info->stream, "g-float");
 241                 p += 8;
 242                 break;
 243
 244               case 'h':
 245                 (*info->fprintf_func) (info->stream, "h-float");
 246                 p += 16;
 247                 break;
 248
 249               }
 250           }
 251         else
 252           (*info->fprintf_func) (info->stream, "(%s)+", REGISTER_NAME (regnum));
 253         break;
 254
 255       case 11:                  /* Byte displacement deferred */
 256         (*info->fprintf_func) (info->stream, "@");
 257       case 10:                  /* Byte displacement */
 258         if (regnum == PC_REGNUM)
 259           {
 260             info->target = addr + *p + 2;
 261             (*info->print_address_func) (info->target, info);
 262           }
 263         else
 264           (*info->fprintf_func) (info->stream, "%d(%s)", *p, REGISTER_NAME (regnum));
 265         p += 1;
 266         break;
 267
 268       case 13:                  /* Word displacement deferred */
 269         (*info->fprintf_func) (info->stream, "@");
 270       case 12:                  /* Word displacement */
 271         if (regnum == PC_REGNUM)
 272           {
 273             info->target = addr + *(short *) p + 3;
 274             (*info->print_address_func) (info->target, info);
 275           }
 276         else
 277           (*info->fprintf_func) (info->stream, "%d(%s)",
 278                                  *(short *) p, REGISTER_NAME (regnum));
 279         p += 2;
 280         break;
 281
 282       case 15:                  /* Long displacement deferred */
 283         (*info->fprintf_func) (info->stream, "@");
 284       case 14:                  /* Long displacement */
 285         if (regnum == PC_REGNUM)
 286           {
 287             info->target = addr + *(short *) p + 5;
 288             (*info->print_address_func) (info->target, info);
 289           }
 290         else
 291           (*info->fprintf_func) (info->stream, "%d(%s)",
 292                                  *(long *) p, REGISTER_NAME (regnum));
 293         p += 4;
 294       }
 295
 296   return (unsigned char *) p;
 297 }
 298
 299 void
 300 _initialize_vax_tdep (void)
 301 {
 302   tm_print_insn = vax_print_insn;
 303 }