ia64-opc.c

xen虚拟机源代码安装包

      int opval[3] = {0};
      int next_op;
      int currbit;

      oplen = extract_op (op_pointer, opval, &op);

      bitpos[currstatenum] = currbitnum;

      /* Skip opval[0] bits in the instruction. */
      if (op & 0x40)
	{
	  currbitnum -= opval[0];
	}

      /* The value of the current bit being tested. */
      currbit = opcode & (((ia64_insn) 1) << currbitnum) ? 1 : 0;
      next_op = -1;

      /* We always perform the tests specified in the current state in
	 a particular order, falling through to the next test if the
	 previous one failed. */
      switch (currtest[currstatenum])
	{
	case 0:
	  currtest[currstatenum]++;
	  if (currbit == 0 && (op & 0x80))
	    {
	      /* Check for a zero bit.  If this test solely checks for
		 a zero bit, we can check for up to 8 consecutive zero
		 bits (the number to check is specified by the lower 3
		 bits in the state code.)

		 If the state instruction matches, we go to the very
		 next state instruction; otherwise, try the next test. */

	      if ((op & 0xf8) == 0x80)
		{
		  int count = op & 0x7;
		  int x;

		  for (x = 0; x <= count; x++)
		    {
		      int i =
			opcode & (((ia64_insn) 1) << (currbitnum - x)) ? 1 : 0;
		      if (i)
			{
			  break;
			}
		    }
		  if (x > count)
		    {
		      next_op = op_pointer + ((oplen + 7) / 8);
		      currbitnum -= count;
		      break;
		    }
		}
	      else if (! currbit)
		{
		  next_op = op_pointer + ((oplen + 7) / 8);
		  break;
		}
	    }
	  /* FALLTHROUGH */
	case 1:
	  /* If the bit in the instruction is one, go to the state
	     instruction specified by opval[1]. */
	  currtest[currstatenum]++;
	  if (currbit && (op & 0x30) != 0 && ((op & 0x30) != 0x30))
	    {
	      next_op = opval[1];
	      break;
	    }
	  /* FALLTHROUGH */
	case 2:
	  /* Don't care.  Skip the current bit and go to the state
	     instruction specified by opval[2].

	     An encoding of 0x30 is special; this means that a 12-bit
	     offset into the ia64_dis_names[] array is specified.  */
	  currtest[currstatenum]++;
	  if ((op & 0x08) || ((op & 0x30) == 0x30))
	    {
	      next_op = opval[2];
	      break;
	    }
	}

      /* If bit 15 is set in the address of the next state, an offset
	 in the ia64_dis_names array was specified instead.  We then
	 check to see if an entry in the list of opcodes matches the
	 opcode we were given; if so, we have succeeded.  */

      if ((next_op >= 0) && (next_op & 32768))
	{
	  short disent = next_op & 32767;
          short priority = -1;

	  if (next_op > 65535)
	    {
	      abort ();
	    }

	  /* Run through the list of opcodes to check, trying to find
	     one that matches.  */
	  while (disent >= 0)
	    {
	      int place = ia64_dis_names[disent].insn_index;

              priority = ia64_dis_names[disent].priority;

	      if (opcode_verify (opcode, place, type)
                  && priority > found_priority)
		{
		  break;
		}
	      if (ia64_dis_names[disent].next_flag)
		{
		  disent++;
		}
	      else
		{
		  disent = -1;
		}
	    }

	  if (disent >= 0)
	    {
              found_disent = disent;
              found_priority = priority;
	    }
          /* Try the next test in this state, regardless of whether a match
             was found. */
          next_op = -2;
	}

      /* next_op == -1 is "back up to the previous state".
	 next_op == -2 is "stay in this state and try the next test".
	 Otherwise, transition to the state indicated by next_op. */

      if (next_op == -1)
	{
	  currstatenum--;
	  if (currstatenum < 0)
	    {
              return found_disent;
	    }
	}
      else if (next_op >= 0)
	{
	  currstatenum++;
	  bitpos[currstatenum] = currbitnum - 1;
	  op_ptr[currstatenum] = next_op;
	  currtest[currstatenum] = 0;
	}
    }
}

/* Construct an ia64_opcode entry based on OPCODE, NAME and PLACE. */

static struct ia64_opcode *
make_ia64_opcode (ia64_insn opcode, const char *name, int place, int depind)
{
  struct ia64_opcode *res =
    (struct ia64_opcode *) malloc (sizeof (struct ia64_opcode));
  res->name = strdup (name);
  res->type = main_table[place].opcode_type;
  res->num_outputs = main_table[place].num_outputs;
  res->opcode = opcode;
  res->mask = main_table[place].mask;
  res->operands[0] = main_table[place].operands[0];
  res->operands[1] = main_table[place].operands[1];
  res->operands[2] = main_table[place].operands[2];
  res->operands[3] = main_table[place].operands[3];
  res->operands[4] = main_table[place].operands[4];
  res->flags = main_table[place].flags;
  res->ent_index = place;
  res->dependencies = &op_dependencies[depind];
  return res;
}

/* Determine the ia64_opcode entry for the opcode specified by INSN
   and TYPE.  If a valid entry is not found, return NULL. */
struct ia64_opcode *
ia64_dis_opcode (ia64_insn insn, enum ia64_insn_type type)
{
  int disent = locate_opcode_ent (insn, type);

  if (disent < 0)
    {
      return NULL;
    }
  else
    {
      unsigned int cb = ia64_dis_names[disent].completer_index;
      static char name[128];
      int place = ia64_dis_names[disent].insn_index;
      int ci = main_table[place].completers;
      ia64_insn tinsn = main_table[place].opcode;

      strcpy (name, ia64_strings [main_table[place].name_index]);

      while (cb)
	{
	  if (cb & 1)
	    {
	      int cname = completer_table[ci].name_index;

	      tinsn = apply_completer (tinsn, ci);

	      if (ia64_strings[cname][0] != '\0')
		{
		  strcat (name, ".");
		  strcat (name, ia64_strings[cname]);
		}
	      if (cb != 1)
		{
		  ci = completer_table[ci].subentries;
		}
	    }
	  else
	    {
	      ci = completer_table[ci].alternative;
	    }
	  if (ci < 0)
	    {
	      abort ();
	    }
	  cb = cb >> 1;
	}
      if (tinsn != (insn & main_table[place].mask))
	{
	  abort ();
	}
      return make_ia64_opcode (insn, name, place,
                               completer_table[ci].dependencies);
    }
}

/* Search the main_opcode table starting from PLACE for an opcode that
   matches NAME.  Return NULL if one is not found. */

static struct ia64_opcode *
ia64_find_matching_opcode (const char *name, short place)
{
  char op[129];
  const char *suffix;
  short name_index;

  if (strlen (name) > 128)
    {
      return NULL;
    }
  suffix = name;
  get_opc_prefix (&suffix, op);
  name_index = find_string_ent (op);
  if (name_index < 0)
    {
      return NULL;
    }

  while (main_table[place].name_index == name_index)
    {
      const char *curr_suffix = suffix;
      ia64_insn curr_insn = main_table[place].opcode;
      short completer = -1;

      do {
	if (suffix[0] == '\0')
	  {
	    completer = find_completer (place, completer, suffix);
	  }
	else
	  {
	    get_opc_prefix (&curr_suffix, op);
	    completer = find_completer (place, completer, op);
	  }
	if (completer != -1)
	  {
	    curr_insn = apply_completer (curr_insn, completer);
	  }
      } while (completer != -1 && curr_suffix[0] != '\0');

      if (completer != -1 && curr_suffix[0] == '\0'
	  && completer_table[completer].terminal_completer)
	{
          int depind = completer_table[completer].dependencies;
	  return make_ia64_opcode (curr_insn, name, place, depind);
	}
      else
	{
	  place++;
	}
    }
  return NULL;
}

/* Find the next opcode after PREV_ENT that matches PREV_ENT, or return NULL
   if one does not exist.

   It is the caller's responsibility to invoke ia64_free_opcode () to
   release any resources used by the returned entry. */

struct ia64_opcode *
ia64_find_next_opcode (struct ia64_opcode *prev_ent)
{
  return ia64_find_matching_opcode (prev_ent->name,
				    prev_ent->ent_index + 1);
}

/* Find the first opcode that matches NAME, or return NULL if it does
   not exist.

   It is the caller's responsibility to invoke ia64_free_opcode () to
   release any resources used by the returned entry. */

struct ia64_opcode *
ia64_find_opcode (const char *name)
{
  char op[129];
  const char *suffix;
  short place;
  short name_index;

  if (strlen (name) > 128)
    {
      return NULL;
    }
  suffix = name;
  get_opc_prefix (&suffix, op);
  name_index = find_string_ent (op);
  if (name_index < 0)
    {
      return NULL;
    }

  place = find_main_ent (name_index);

  if (place < 0)
    {
      return NULL;
    }
  return ia64_find_matching_opcode (name, place);
}

/* Free any resources used by ENT. */
void
ia64_free_opcode (struct ia64_opcode *ent)
{
  free ((void *)ent->name);
  free (ent);
}

const struct ia64_dependency *
ia64_find_dependency (int index)
{
  index = DEP(index);

  if (index < 0
      || index >= (int)(sizeof(dependencies) / sizeof(dependencies[0])))
    return NULL;

  return &dependencies[index];
}