m68k-dis.c

qemu虚拟机代码

      if (place == 'b')
	disp = NEXTBYTE (p);
      else if (place == 'B')
	disp = COERCE_SIGNED_CHAR (buffer[1]);
      else if (place == 'w' || place == 'W')
	disp = NEXTWORD (p);
      else if (place == 'l' || place == 'L' || place == 'C')
	disp = NEXTLONG (p);
      else if (place == 'g')
	{
	  disp = NEXTBYTE (buffer);
	  if (disp == 0)
	    disp = NEXTWORD (p);
	  else if (disp == -1)
	    disp = NEXTLONG (p);
	}
      else if (place == 'c')
	{
	  if (buffer[1] & 0x40)		/* If bit six is one, long offset.  */
	    disp = NEXTLONG (p);
	  else
	    disp = NEXTWORD (p);
	}
      else
	return -2;

      (*info->print_address_func) (addr + disp, info);
      break;

    case 'd':
      val = NEXTWORD (p);
      (*info->fprintf_func)
	(info->stream, "%s@(%d)",
	 reg_names[fetch_arg (buffer, place, 3, info) + 8], val);
      break;

    case 's':
      (*info->fprintf_func) (info->stream, "%s",
			     fpcr_names[fetch_arg (buffer, place, 3, info)]);
      break;

    case 'e':
      val = fetch_arg(buffer, place, 2, info);
      (*info->fprintf_func) (info->stream, "%%acc%d", val);
      break;

    case 'g':
      val = fetch_arg(buffer, place, 1, info);
      (*info->fprintf_func) (info->stream, "%%accext%s", val==0 ? "01" : "23");
      break;

    case 'i':
      val = fetch_arg(buffer, place, 2, info);
      if (val == 1)
	(*info->fprintf_func) (info->stream, "<<");
      else if (val == 3)
	(*info->fprintf_func) (info->stream, ">>");
      else
	return -1;
      break;

    case 'I':
      /* Get coprocessor ID... */
      val = fetch_arg (buffer, 'd', 3, info);

      if (val != 1)				/* Unusual coprocessor ID?  */
	(*info->fprintf_func) (info->stream, "(cpid=%d) ", val);
      break;

    case '4':
    case '*':
    case '~':
    case '%':
    case ';':
    case '@':
    case '!':
    case '$':
    case '?':
    case '/':
    case '&':
    case '|':
    case '<':
    case '>':
    case 'm':
    case 'n':
    case 'o':
    case 'p':
    case 'q':
    case 'v':
    case 'b':
    case 'w':
    case 'y':
    case 'z':
      if (place == 'd')
	{
	  val = fetch_arg (buffer, 'x', 6, info);
	  val = ((val & 7) << 3) + ((val >> 3) & 7);
	}
      else
	val = fetch_arg (buffer, 's', 6, info);

      /* If the <ea> is invalid for *d, then reject this match.  */
      if (!m68k_valid_ea (*d, val))
	return -1;

      /* Get register number assuming address register.  */
      regno = (val & 7) + 8;
      regname = reg_names[regno];
      switch (val >> 3)
	{
	case 0:
	  (*info->fprintf_func) (info->stream, "%s", reg_names[val]);
	  break;

	case 1:
	  (*info->fprintf_func) (info->stream, "%s", regname);
	  break;

	case 2:
	  (*info->fprintf_func) (info->stream, "%s@", regname);
	  break;

	case 3:
	  (*info->fprintf_func) (info->stream, "%s@+", regname);
	  break;

	case 4:
	  (*info->fprintf_func) (info->stream, "%s@-", regname);
	  break;

	case 5:
	  val = NEXTWORD (p);
	  (*info->fprintf_func) (info->stream, "%s@(%d)", regname, val);
	  break;

	case 6:
	  p = print_indexed (regno, p, addr, info);
	  break;

	case 7:
	  switch (val & 7)
	    {
	    case 0:
	      val = NEXTWORD (p);
	      (*info->print_address_func) (val, info);
	      break;

	    case 1:
	      uval = NEXTULONG (p);
	      (*info->print_address_func) (uval, info);
	      break;

	    case 2:
	      val = NEXTWORD (p);
	      (*info->fprintf_func) (info->stream, "%%pc@(");
	      (*info->print_address_func) (addr + val, info);
	      (*info->fprintf_func) (info->stream, ")");
	      break;

	    case 3:
	      p = print_indexed (-1, p, addr, info);
	      break;

	    case 4:
	      flt_p = 1;	/* Assume it's a float... */
	      switch (place)
	      {
		case 'b':
		  val = NEXTBYTE (p);
		  flt_p = 0;
		  break;

		case 'w':
		  val = NEXTWORD (p);
		  flt_p = 0;
		  break;

		case 'l':
		  val = NEXTLONG (p);
		  flt_p = 0;
		  break;

		case 'f':
		  NEXTSINGLE (flval, p);
		  break;

		case 'F':
		  NEXTDOUBLE (flval, p);
		  break;

		case 'x':
		  NEXTEXTEND (flval, p);
		  break;

		case 'p':
		  flval = NEXTPACKED (p);
		  break;

		default:
		  return -1;
	      }
	      if (flt_p)	/* Print a float? */
		(*info->fprintf_func) (info->stream, "#%g", flval);
	      else
		(*info->fprintf_func) (info->stream, "#%d", val);
	      break;

	    default:
	      return -1;
	    }
	}

      /* If place is '/', then this is the case of the mask bit for
	 mac/emac loads. Now that the arg has been printed, grab the
	 mask bit and if set, add a '&' to the arg.  */
      if (place == '/')
	{
	  val = fetch_arg (buffer, place, 1, info);
	  if (val)
	    info->fprintf_func (info->stream, "&");
	}
      break;

    case 'L':
    case 'l':
	if (place == 'w')
	  {
	    char doneany;
	    p1 = buffer + 2;
	    val = NEXTWORD (p1);
	    /* Move the pointer ahead if this point is farther ahead
	       than the last.  */
	    p = p1 > p ? p1 : p;
	    if (val == 0)
	      {
		(*info->fprintf_func) (info->stream, "#0");
		break;
	      }
	    if (*d == 'l')
	      {
		int newval = 0;

		for (regno = 0; regno < 16; ++regno)
		  if (val & (0x8000 >> regno))
		    newval |= 1 << regno;
		val = newval;
	      }
	    val &= 0xffff;
	    doneany = 0;
	    for (regno = 0; regno < 16; ++regno)
	      if (val & (1 << regno))
		{
		  int first_regno;

		  if (doneany)
		    (*info->fprintf_func) (info->stream, "/");
		  doneany = 1;
		  (*info->fprintf_func) (info->stream, "%s", reg_names[regno]);
		  first_regno = regno;
		  while (val & (1 << (regno + 1)))
		    ++regno;
		  if (regno > first_regno)
		    (*info->fprintf_func) (info->stream, "-%s",
					   reg_names[regno]);
		}
	  }
	else if (place == '3')
	  {
	    /* `fmovem' insn.  */
	    char doneany;
	    val = fetch_arg (buffer, place, 8, info);
	    if (val == 0)
	      {
		(*info->fprintf_func) (info->stream, "#0");
		break;
	      }
	    if (*d == 'l')
	      {
		int newval = 0;

		for (regno = 0; regno < 8; ++regno)
		  if (val & (0x80 >> regno))
		    newval |= 1 << regno;
		val = newval;
	      }
	    val &= 0xff;
	    doneany = 0;
	    for (regno = 0; regno < 8; ++regno)
	      if (val & (1 << regno))
		{
		  int first_regno;
		  if (doneany)
		    (*info->fprintf_func) (info->stream, "/");
		  doneany = 1;
		  (*info->fprintf_func) (info->stream, "%%fp%d", regno);
		  first_regno = regno;
		  while (val & (1 << (regno + 1)))
		    ++regno;
		  if (regno > first_regno)
		    (*info->fprintf_func) (info->stream, "-%%fp%d", regno);
		}
	  }
	else if (place == '8')
	  {
	    /* fmoveml for FP status registers.  */
	    (*info->fprintf_func) (info->stream, "%s",
				   fpcr_names[fetch_arg (buffer, place, 3,
							 info)]);
	  }
	else
	  return -2;
      break;

    case 'X':
      place = '8';
    case 'Y':
    case 'Z':
    case 'W':
    case '0':
    case '1':
    case '2':
    case '3':
      {
	int val = fetch_arg (buffer, place, 5, info);
	char *name = 0;

	switch (val)
	  {
	  case 2: name = "%tt0"; break;
	  case 3: name = "%tt1"; break;
	  case 0x10: name = "%tc"; break;
	  case 0x11: name = "%drp"; break;
	  case 0x12: name = "%srp"; break;
	  case 0x13: name = "%crp"; break;
	  case 0x14: name = "%cal"; break;
	  case 0x15: name = "%val"; break;
	  case 0x16: name = "%scc"; break;
	  case 0x17: name = "%ac"; break;
 	  case 0x18: name = "%psr"; break;
	  case 0x19: name = "%pcsr"; break;
	  case 0x1c:
	  case 0x1d:
	    {
	      int break_reg = ((buffer[3] >> 2) & 7);

	      (*info->fprintf_func)
		(info->stream, val == 0x1c ? "%%bad%d" : "%%bac%d",
		 break_reg);
	    }
	    break;
	  default:
	    (*info->fprintf_func) (info->stream, "<mmu register %d>", val);
	  }
	if (name)
	  (*info->fprintf_func) (info->stream, "%s", name);
      }
      break;

    case 'f':
      {
	int fc = fetch_arg (buffer, place, 5, info);

	if (fc == 1)
	  (*info->fprintf_func) (info->stream, "%%dfc");
	else if (fc == 0)
	  (*info->fprintf_func) (info->stream, "%%sfc");
	else
	  /* xgettext:c-format */
	  (*info->fprintf_func) (info->stream, _("<function code %d>"), fc);
      }
      break;

    case 'V':
      (*info->fprintf_func) (info->stream, "%%val");
      break;

    case 't':
      {
	int level = fetch_arg (buffer, place, 3, info);

	(*info->fprintf_func) (info->stream, "%d", level);
      }
      break;

    case 'u':
      {
	short is_upper = 0;
	int reg = fetch_arg (buffer, place, 5, info);

	if (reg & 0x10)
	  {
	    is_upper = 1;
	    reg &= 0xf;
	  }
	(*info->fprintf_func) (info->stream, "%s%s",
			       reg_half_names[reg],
			       is_upper ? "u" : "l");
      }
      break;

    default:
      return -2;
    }

  return p - p0;
}

/* Try to match the current instruction to best and if so, return the
   number of bytes consumed from the instruction stream, else zero.  */

static int
match_insn_m68k (bfd_vma memaddr,
		 disassemble_info * info,
		 const struct m68k_opcode * best,
		 struct private * priv)
{
  unsigned char *save_p;
  unsigned char *p;
  const char *d;

  bfd_byte *buffer = priv->the_buffer;
  fprintf_ftype save_printer = info->fprintf_func;
  void (* save_print_address) (bfd_vma, struct disassemble_info *)
    = info->print_address_func;

  /* Point at first word of argument data,
     and at descriptor for first argument.  */
  p = buffer + 2;

  /* Figure out how long the fixed-size portion of the instruction is.
     The only place this is stored in the opcode table is
     in the arguments--look for arguments which specify fields in the 2nd
     or 3rd words of the instruction.  */
  for (d = best->args; *d; d += 2)
    {
      /* I don't think it is necessary to be checking d[0] here;
	 I suspect all this could be moved to the case statement below.  */