gen.c

这个是LINUX下的GDB调度工具的源码

    return new_field;
  }
}


static void
gen_entry_insert_insn (gen_entry *table,
		       insn_entry * old_insn,
		       int new_word_nr,
		       int new_nr_prefetched_words,
		       int new_opcode_nr, opcode_bits *new_bits)
{
  gen_entry **entry = &table->entries;

  /* find the new table for this entry */
  while ((*entry) != NULL && (*entry)->opcode_nr < new_opcode_nr)
    {
      entry = &(*entry)->sibling;
    }

  if ((*entry) == NULL || (*entry)->opcode_nr != new_opcode_nr)
    {
      /* insert the missing entry */
      gen_entry *new_entry = ZALLOC (gen_entry);
      new_entry->sibling = (*entry);
      (*entry) = new_entry;
      table->nr_entries++;
      /* fill it in */
      new_entry->top = table->top;
      new_entry->opcode_nr = new_opcode_nr;
      new_entry->word_nr = new_word_nr;
      new_entry->expanded_bits = new_bits;
      new_entry->opcode_rule = table->opcode_rule->next;
      new_entry->parent = table;
      new_entry->nr_prefetched_words = new_nr_prefetched_words;
    }
  /* ASSERT new_bits == cur_entry bits */
  ASSERT ((*entry) != NULL && (*entry)->opcode_nr == new_opcode_nr);
  insn_list_insert (&(*entry)->insns, &(*entry)->nr_insns, old_insn, NULL,	/* expanded_bits - only in final list */
		    NULL,	/* opcodes - only in final list */
		    new_nr_prefetched_words,	/* for this table */
		    report_duplicate_insns);
}


static void
gen_entry_expand_opcode (gen_entry *table,
			 insn_entry * instruction,
			 int bit_nr, int opcode_nr, opcode_bits *bits)
{
  if (bit_nr > table->opcode->last)
    {
      /* Only include the hardwired bit information with an entry IF
         that entry (and hence its functions) are being duplicated.  */
      if (options.trace.insn_expansion)
	{
	  print_gen_entry_path (table->opcode_rule->line, table, notify);
	  notify (NULL, ": insert %d - %s.%s%s\n",
		  opcode_nr,
		  instruction->format_name,
		  instruction->name,
		  (table->opcode_rule->
		   with_duplicates ? " (duplicated)" : ""));
	}
      if (table->opcode_rule->with_duplicates)
	{
	  gen_entry_insert_insn (table, instruction,
				 table->opcode->word_nr,
				 table->nr_prefetched_words, opcode_nr, bits);
	}
      else
	{
	  gen_entry_insert_insn (table, instruction,
				 table->opcode->word_nr,
				 table->nr_prefetched_words, opcode_nr, NULL);
	}
    }
  else
    {
      insn_word_entry *word = instruction->word[table->opcode->word_nr];
      insn_field_entry *field = word->bit[bit_nr]->field;
      int last_pos = ((field->last < table->opcode->last)
		      ? field->last : table->opcode->last);
      int first_pos = ((field->first > table->opcode->first)
		       ? field->first : table->opcode->first);
      int width = last_pos - first_pos + 1;
      switch (field->type)
	{
	case insn_field_int:
	  {
	    int val;
	    val = sub_val (field->val_int, field->last, first_pos, last_pos);
	    gen_entry_expand_opcode (table, instruction,
				     last_pos + 1,
				     ((opcode_nr << width) | val), bits);
	    break;
	  }
	default:
	  {
	    if (field->type == insn_field_reserved)
	      gen_entry_expand_opcode (table, instruction,
				       last_pos + 1,
				       ((opcode_nr << width)), bits);
	    else
	      {
		int val;
		int last_val = (table->opcode->is_boolean ? 2 : (1 << width));
		for (val = 0; val < last_val; val++)
		  {
		    /* check to see if the value has been precluded
		       (by a conditional) in some way */
		    int is_precluded;
		    insn_field_cond *condition;
		    for (condition = field->conditions, is_precluded = 0;
			 condition != NULL && !is_precluded;
			 condition = condition->next)
		      {
			switch (condition->type)
			  {
			  case insn_field_cond_value:
			    {
			      int value =
				sub_val (condition->value, field->last,
					 first_pos, last_pos);
			      switch (condition->test)
				{
				case insn_field_cond_ne:
				  if (value == val)
				    is_precluded = 1;
				  break;
				case insn_field_cond_eq:
				  if (value != val)
				    is_precluded = 1;
				  break;
				}
			      break;
			    }
			  case insn_field_cond_field:
			    {
			      int value = -1;
			      opcode_bits *bit;
			      gen_entry *t = NULL;
			      /* Try to find a value for the
			         conditional by looking back through
			         the previously defined bits for one
			         that covers the designated
			         conditional field */
			      for (bit = bits; bit != NULL; bit = bit->next)
				{
				  if (bit->field->word_nr ==
				      condition->field->word_nr
				      && bit->first <= condition->field->first
				      && bit->last >= condition->field->last)
				    {
				      /* the bit field fully specified
				         the conditional field's value */
				      value = sub_val (bit->value, bit->last,
						       condition->field->
						       first,
						       condition->field->
						       last);
				    }
				}
			      /* Try to find a value by looking
			         through this and previous tables */
			      if (bit == NULL)
				{
				  for (t = table;
				       t->parent != NULL; t = t->parent)
				    {
				      if (t->parent->opcode->word_nr ==
					  condition->field->word_nr
					  && t->parent->opcode->first <=
					  condition->field->first
					  && t->parent->opcode->last >=
					  condition->field->last)
					{
					  /* the table entry fully
					     specified the condition
					     field's value */
					  /* extract the field's value
					     from the opcode */
					  value =
					    sub_val (t->opcode_nr,
						     t->parent->opcode->last,
						     condition->field->first,
						     condition->field->last);
					  /* this is a requirement of
					     a conditonal field
					     refering to another field */
					  ASSERT ((condition->field->first -
						   condition->field->last) ==
						  (first_pos - last_pos));
					  printf
					    ("value=%d, opcode_nr=%d, last=%d, [%d..%d]\n",
					     value, t->opcode_nr,
					     t->parent->opcode->last,
					     condition->field->first,
					     condition->field->last);
					}
				    }
				}
			      if (bit == NULL && t == NULL)
				error (instruction->line,
				       "Conditional `%s' of field `%s' isn't expanded",
				       condition->string, field->val_string);
			      switch (condition->test)
				{
				case insn_field_cond_ne:
				  if (value == val)
				    is_precluded = 1;
				  break;
				case insn_field_cond_eq:
				  if (value != val)
				    is_precluded = 1;
				  break;
				}
			      break;
			    }
			  }
		      }
		    if (!is_precluded)
		      {
			/* Only add additional hardwired bit
			   information if the entry is not going to
			   later be combined */
			if (table->opcode_rule->with_combine)
			  {
			    gen_entry_expand_opcode (table, instruction,
						     last_pos + 1,
						     ((opcode_nr << width) |
						      val), bits);
			  }
			else
			  {
			    opcode_bits *new_bits =
			      new_opcode_bits (bits, val,
					       first_pos, last_pos,
					       field,
					       table->opcode);
			    gen_entry_expand_opcode (table, instruction,
						     last_pos + 1,
						     ((opcode_nr << width) |
						      val), new_bits);
			  }
		      }
		  }
	      }
	  }
	}
    }
}

static void
gen_entry_insert_expanding (gen_entry *table, insn_entry * instruction)
{
  gen_entry_expand_opcode (table,
			   instruction,
			   table->opcode->first, 0, table->expanded_bits);
}


static int
insns_match_format_names (insn_list *insns, filter *format_names)
{
  if (format_names != NULL)
    {
      insn_list *i;
      for (i = insns; i != NULL; i = i->next)
	{
	  if (i->insn->format_name != NULL
	      && !filter_is_member (format_names, i->insn->format_name))
	    return 0;
	}
    }
  return 1;
}

static int
table_matches_path (gen_entry *table, decode_path_list *paths)
{
  if (paths == NULL)
    return 1;
  while (paths != NULL)
    {
      gen_entry *entry = table;
      decode_path *path = paths->path;
      while (1)
	{
	  if (entry == NULL && path == NULL)
	    return 1;
	  if (entry == NULL || path == NULL)
	    break;
	  if (entry->opcode_nr != path->opcode_nr)
	    break;
	  entry = entry->parent;
	  path = path->parent;
	}
      paths = paths->next;
    }
  return 0;
}


static int
insns_match_conditions (insn_list *insns, decode_cond *conditions)
{
  if (conditions != NULL)
    {
      insn_list *i;
      for (i = insns; i != NULL; i = i->next)
	{
	  decode_cond *cond;
	  for (cond = conditions; cond != NULL; cond = cond->next)
	    {
	      int bit_nr;
	      if (i->insn->nr_words <= cond->word_nr)
		return 0;
	      for (bit_nr = 0; bit_nr < options.insn_bit_size; bit_nr++)
		{
		  if (!cond->mask[bit_nr])
		    continue;
		  if (!i->insn->word[cond->word_nr]->bit[bit_nr]->mask)
		    return 0;
		  if ((i->insn->word[cond->word_nr]->bit[bit_nr]->value
		       == cond->value[bit_nr]) == !cond->is_equal)
		    return 0;
		}
	    }
	}
    }
  return 1;
}

static int
insns_match_nr_words (insn_list *insns, int nr_words)
{
  insn_list *i;
  for (i = insns; i != NULL; i = i->next)
    {
      if (i->insn->nr_words < nr_words)
	return 0;
    }
  return 1;
}

static int
insn_list_cmp (insn_list *l, insn_list *r)
{
  while (1)
    {
      insn_entry *insn;
      if (l == NULL && r == NULL)
	return 0;
      if (l == NULL)
	return -1;
      if (r == NULL)
	return 1;
      if (l->insn != r->insn)
	return -1;		/* somewhat arbitrary at present */
      /* skip this insn */
      insn = l->insn;
      while (l != NULL && l->insn == insn)
	l = l->next;
      while (r != NULL && r->insn == insn)
	r = r->next;
    }
}



static void
gen_entry_expand_insns (gen_entry *table)
{
  decode_table *opcode_rule;

  ASSERT (table->nr_insns >= 1);

  /* determine a valid opcode */
  for (opcode_rule = table->opcode_rule;
       opcode_rule != NULL; opcode_rule = opcode_rule->next)
    {
      char *discard_reason;
      if (table->top->model != NULL
	  && opcode_rule->model_names != NULL
	  && !filter_is_member (opcode_rule->model_names,
				table->top->model->name))
	{
	  /* the rule isn't applicable to this processor */
	  discard_reason = "wrong model";
	}
      else if (table->nr_insns == 1 && opcode_rule->conditions == NULL)
	{
	  /* for safety, require a pre-codition when attempting to
	     apply a rule to a single instruction */
	  discard_reason = "need pre-condition when nr-insn == 1";
	}
      else if (table->nr_insns == 1 && !opcode_rule->with_duplicates)
	{
	  /* Little point in expanding a single instruction when we're
	     not duplicating the semantic functions that this table
	     calls */
	  discard_reason = "need duplication with nr-insns == 1";
	}
      else
	if (!insns_match_format_names
	    (table->insns, opcode_rule->format_names))
	{
	  discard_reason = "wrong format name";
	}
      else if (!insns_match_nr_words (table->insns, opcode_rule->word_nr + 1))
	{
	  discard_reason = "wrong nr words";
	}
      else if (!table_matches_path (table, opcode_rule->paths))
	{
	  discard_reason = "path failed";
	}
      else
	if (!insns_match_conditions (table->insns, opcode_rule->conditions))
	{
	  discard_reason = "condition failed";
	}
      else
	{
	  discard_reason = "no opcode field";
	  table->opcode = gen_entry_find_opcode_field (table->insns,
						       opcode_rule,
						       table->nr_insns == 1	/*string-only */
	    );
	  if (table->opcode != NULL)
	    {
	      table->opcode_rule = opcode_rule;
	      break;
	    }
	}

      if (options.trace.rule_rejection)
	{
	  print_gen_entry_path (opcode_rule->line, table, notify);
	  notify (NULL, ": rule discarded - %s\n", discard_reason);
	}