tc-i370.c

基于4个mips核的noc设计

      literals[next_literal_pool_place].exp = *exx;
      literals[next_literal_pool_place].size = sz;
      literals[next_literal_pool_place].offset = offset_in_pool;
      if (name)
	{
	  literals[next_literal_pool_place].sym_name = strdup (name);
	}
      else
	{
	  literals[next_literal_pool_place].sym_name = NULL;
	}
      next_literal_pool_place++;
    }

  /* ???_poolP points to the begining of the literal pool.
   * X_add_number is the offset from the begining of the
   * literal pool to this expr minus the location of the most
   * recent .using directive.  Thus, the grand total value of the
   * expression is the distance from .using to the literal.
   */
  if (8 == sz)
    exx->X_add_symbol = longlong_poolP;
  else if (4 == sz)
    exx->X_add_symbol = word_poolP;
  else if (2 == sz)
    exx->X_add_symbol = short_poolP;
  else if (1 == sz)
    exx->X_add_symbol = byte_poolP;
  exx->X_add_number = offset_in_pool;
  exx->X_op_symbol = NULL;

  /* If the user has set up a base reg in another section,
   * use that; otherwise use the text section.  */
  if (0 < i370_using_other_regno)
    {
      i370_make_relative (exx, &i370_using_other_baseaddr);
    }
  else
    {
      i370_make_relative (exx, &i370_using_text_baseaddr);
    }
}

/* The symbol setup for the literal pool is done in two steps.  First,
 * a symbol that represents the start of the literal pool is created,
 * above, in the add_to_pool() routine. This sym ???_poolP.
 * However, we don't know what fragment its in until a bit later.
 * So we defer the frag_now thing, and the symbol name, until .ltorg time
 */

/* Can't use symbol_new here, so have to create a symbol and then at
   a later date assign it a value. Thats what these functions do */
static void
symbol_locate (symbolP, name, segment, valu, frag)
     symbolS *symbolP;
     CONST char *name;		/* It is copied, the caller can modify */
     segT segment;		/* Segment identifier (SEG_<something>) */
     valueT valu;		/* Symbol value */
     fragS *frag;		/* Associated fragment */
{
  size_t name_length;
  char *preserved_copy_of_name;

  name_length = strlen (name) + 1;      /* +1 for \0 */
  obstack_grow (&notes, name, name_length);
  preserved_copy_of_name = obstack_finish (&notes);

  S_SET_NAME (symbolP, preserved_copy_of_name);

  S_SET_SEGMENT (symbolP, segment);
  S_SET_VALUE (symbolP, valu);
  symbol_clear_list_pointers(symbolP);

  symbol_set_frag (symbolP, frag);

  /*
   * Link to end of symbol chain.
   */
  {
    extern int symbol_table_frozen;
    if (symbol_table_frozen)
      abort ();
  }

  symbol_append (symbolP, symbol_lastP, &symbol_rootP, &symbol_lastP);

  obj_symbol_new_hook (symbolP);

#ifdef tc_symbol_new_hook
  tc_symbol_new_hook (symbolP);
#endif

#define DEBUG_SYMS
#ifdef DEBUG_SYMS
  verify_symbol_chain(symbol_rootP, symbol_lastP);
#endif /* DEBUG_SYMS */
}

/* i370_addr_offset() will convert operand expressions
 * that appear to be absolute into thier base-register
 * relative form.  These expressions come in two types:
 *
 * (1) of the form "* + const" * where "*" means
 * relative offset since the last using
 * i.e. "*" means ".-using_baseaddr"
 *
 * (2) labels, which are never absolute, but are always
 * relative to the last "using".  Anything with an alpha
 * character is considered to be a label (since symbols
 * can never be operands), and since we've already handled
 * register operands. For example, "BL .L33" branch low
 * to .L33 RX form insn frequently terminates for-loops,
 */
static boolean
i370_addr_offset (expressionS *exx)
{
  char *dot, *lab;
  int islabel = 0;
  int all_digits = 0;

  /* search for a label; anything with an alpha char will do */
  /* local labels consist of N digits followed by either b or f */
  lab = input_line_pointer;
  while (*lab && (',' != *lab) && ('(' != *lab))
    {
      if (isdigit(*lab))
	{
	  all_digits = 1;
	}
      else if (isalpha(*lab))
	{
	  if (!all_digits)
	    {
	      islabel = 1;
	      break;
	    }
	  else if (('f' == *lab) || ('b' == *lab))
	    {
	      islabel = 1;
	      break;
	    }
	  if (all_digits)
	    break;
	}
      else if ('.' != *lab)
        break;
      ++lab;
    }

  /* See if operand has a * in it */
  dot = strchr (input_line_pointer, '*');

  if (!dot && !islabel)
    return false;

  /* replace * with . and let expr munch on it.  */
  if (dot)
    *dot = '.';
  expression (exx);

  /* OK, now we have to subtract the "using" location  */
  /* normally branches appear in the text section only...  */
  if (0 == strncmp (now_seg->name, ".text", 5) || 0 > i370_using_other_regno)
    {
      i370_make_relative (exx, &i370_using_text_baseaddr);
    }
  else
    {
      i370_make_relative (exx, &i370_using_other_baseaddr);
    }

  /* put the * back */
  if (dot)
    *dot = '*';

  return true;
}

/* handle address constants of various sorts */
/* The currently supported types are
 *    =A(some_symb)
 *    =V(some_extern)
 *    =X'deadbeef'    hexadecimal
 *    =F'1234'        32-bit const int
 *    =H'1234'        16-bit const int
 */
static boolean
i370_addr_cons (expressionS *exp)
{
  char *name;
  char *sym_name, delim;
  int name_len;
  int hex_len=0;
  int cons_len=0;

  name = input_line_pointer;
  sym_name = input_line_pointer;
  /* Find the spelling of the operand */
  if (name[0] == '=' && isalpha (name[1]))
    {
      name = ++input_line_pointer;
    }
  else
    {
      return false;
    }
  switch (name[0])
    {
    case 'A':
    case 'V':
      /* A == address-of */
      /* V == extern */
      ++input_line_pointer;
      expression (exp);

      /* we use a simple string name to collapse together
       * multiple refrences to the same address literal
       */
      name_len = strcspn (sym_name, ", ");
      delim = *(sym_name + name_len);
      *(sym_name + name_len) = 0x0;
      add_to_lit_pool (exp, sym_name, 4);
      *(sym_name + name_len) = delim;

      break;
    case 'H':
    case 'F':
    case 'X':
    case 'E':  /* single-precision float point */
    case 'D':  /* double-precision float point */

      /* H == 16-bit fixed-point const; expression must be const */
      /* F == fixed-point const; expression must be const */
      /* X == fixed-point const; expression must be const */
      if ('H' == name[0]) cons_len = 2;
      else if ('F' == name[0]) cons_len = 4;
      else if ('X' == name[0]) cons_len = -1;
      else if ('E' == name[0]) cons_len = 4;
      else if ('D' == name[0]) cons_len = 8;

      /* extract length, if it is present; hack alert -- assume single-digit
       * length */
      if ('L' == name[1])
	{
	  cons_len = name[2] - '0';  /* should work for ascii and ebcdic */
	  input_line_pointer += 2;
	}

      ++input_line_pointer;

      /* get rid of pesky quotes */
      if ('\'' == *input_line_pointer)
	{
	  char * close;
	  ++input_line_pointer;
	  close = strchr (input_line_pointer, '\'');
	  if (close)
	    *close= ' ';
	  else
	    as_bad ("missing end-quote");
	}
      if ('\"' == *input_line_pointer)
	{
	  char * close;
	  ++input_line_pointer;
	  close = strchr (input_line_pointer, '\"');
	  if (close)
	    *close= ' ';
	  else
	    as_bad ("missing end-quote");
	}
      if (('X' == name[0]) || ('E' == name[0]) || ('D' == name[0]))
	{
	  char tmp[50];
	  char *save;

	  /* The length of hex constants is specified directly with L,
	   * or implied through the number of hex digits. For example:
	   * =X'AB'       one byte
	   * =X'abcd'     two bytes
	   * =X'000000AB' four bytes
	   * =XL4'AB'     four bytes, left-padded withn zero
	   */
	  if (('X' == name[0]) && (0 > cons_len))
	    {
	      save = input_line_pointer;
	      while (*save)
		{
		  if (isxdigit(*save))
		    hex_len++;
		  save++;
		}
	      cons_len = (hex_len+1) /2;
	    }
	  /* I beleive this works even for =XL8'dada0000beeebaaa'
	   * which should parse out to X_op == O_big
	   * Note that floats and doubles get represented as
	   * 0d3.14159265358979  or 0f 2.7
	   */
	  tmp[0] = '0';
	  tmp[1] = name[0];
	  tmp[2] = 0;
	  strcat (tmp, input_line_pointer);
	  save = input_line_pointer;
	  input_line_pointer = tmp;
	  expression (exp);
	  input_line_pointer = save + (input_line_pointer-tmp-2);

	  /* fix up lengths for floats and doubles */
	  if (O_big == exp->X_op)
	    {
	      exp->X_add_number = cons_len / CHARS_PER_LITTLENUM;
	    }
	}
      else
	{
	  expression (exp);
	}
      /* O_big occurs when more than 4 bytes worth gets parsed */
      if ((exp->X_op != O_constant) && (exp->X_op != O_big))
	{
	  as_bad ("expression not a constant");
	  return false;
	}
      add_to_lit_pool (exp, 0x0, cons_len);
      break;

    default:
      as_bad ("Unknown/unsupported address literal type");
      return false;
    }

  return true;
}


/* Dump the contents of the literal pool that we've accumulated so far.
 * This aligns the pool to the size of the largest literal in the pool.
 */

static void
i370_ltorg (ignore)
     int ignore;
{
  int litsize;
  int lit_count = 0;
  int biggest_literal_size = 0;
  int biggest_align = 0;
  char pool_name[20];

  if (strncmp (now_seg->name, ".text", 5))
    {
      if (i370_other_section == undefined_section)
        {
          as_bad (".ltorg without prior .using in section %s",
		  now_seg->name);
        }
      if (i370_other_section != now_seg)
        {
	  as_bad (".ltorg in section %s paired to .using in section %s",
		  now_seg->name, i370_other_section->name);
        }
    }
  if (! longlong_poolP
      && ! word_poolP
      && ! short_poolP
      && ! byte_poolP)
    {
      /* Nothing to do */
      /* as_tsktsk ("Nothing to put in the pool\n"); */
      return;
    }

  /* find largest literal .. 2 4 or 8 */
  lit_count = 0;
  while (lit_count < next_literal_pool_place)
    {
      if (biggest_literal_size < literals[lit_count].size)
	biggest_literal_size = literals[lit_count].size;
      lit_count ++;
    }
  if (1 == biggest_literal_size) biggest_align = 0;
  else if (2 == biggest_literal_size) biggest_align = 1;
  else if (4 == biggest_literal_size) biggest_align = 2;
  else if (8 == biggest_literal_size) biggest_align = 3;
  else as_bad ("bad alignment of %d bytes in literal pool", biggest_literal_size);
  if (0 == biggest_align) biggest_align = 1;

  /* Align pool for short, word, double word accesses */
  frag_align (biggest_align, 0, 0);
  record_alignment (now_seg, biggest_align);

  /* Note that the gas listing will print only the first five
   * entries in the pool .... wonder how to make it print more ...
   */
  /* output largest literals first, then the smaller ones.  */
  for (litsize=8; litsize; litsize /=2)
    {
      symbolS *current_poolP = NULL;
      switch (litsize)
	{
	case 8:
	  current_poolP = longlong_poolP; break;
	case 4:
	  current_poolP = word_poolP; break;
	case 2:
	  current_poolP = short_poolP; break;
	case 1:
	  current_poolP = byte_poolP; break;
	default:
	  as_bad ("bad literal size\n");
	}
      if (NULL == current_poolP)
	continue;
      sprintf (pool_name, ".LITP%01d%06d", litsize, lit_pool_num);
      symbol_locate (current_poolP, pool_name, now_seg,
		     (valueT) frag_now_fix (), frag_now);
      symbol_table_insert (current_poolP);

      lit_count = 0;
      while (lit_count < next_literal_pool_place)
	{
	  if (litsize == literals[lit_count].size)
	    {
#define EMIT_ADDR_CONS_SYMBOLS
#ifdef EMIT_ADDR_CONS_SYMBOLS
	      /* create a bogus symbol, add it to the pool ...
	       * For the most part, I think this is a useless excercise,
	       * except that having these symbol names in the objects
	       * is vaguely useful for debugging ...
	       */
	      if (literals[lit_count].sym_name)
		{
		  symbolS * symP = symbol_make_empty();
		  symbol_locate (symP, literals[lit_count].sym_name, now_seg,
				 (valueT) frag_now_fix (), frag_now);
		  symbol_table_insert (symP);
		}
#endif /* EMIT_ADDR_CONS_SYMBOLS */

	      emit_expr (&(literals[lit_count].exp), literals[lit_count].size);
	    }
	  lit_count ++;
	}
    }

  next_literal_pool_place = 0;
  longlong_poolP = NULL;
  word_poolP = NULL;
  short_poolP = NULL;
  byte_poolP = NULL;
  lit_pool_num++;
}