tc-fr30.c

基于4个mips核的noc设计

   fragP->fr_type == rs_machine_dependent.
   fragP->fr_subtype is the subtype of what the address relaxed to.  */

void
md_convert_frag (abfd, sec, fragP)
  bfd *   abfd;
  segT    sec;
  fragS * fragP;
{
#if 0
  char * opcode;
  char * displacement;
  int    target_address;
  int    opcode_address;
  int    extension;
  int    addend;

  opcode = fragP->fr_opcode;

  /* Address opcode resides at in file space.  */
  opcode_address = fragP->fr_address + fragP->fr_fix - 2;

  switch (fragP->fr_subtype)
    {
    case 1 :
      extension = 0;
      displacement = & opcode[1];
      break;
    case 2 :
      opcode[0] |= 0x80;
      extension = 2;
      displacement = & opcode[1];
      break;
    case 3 :
      opcode[2] = opcode[0] | 0x80;
      md_number_to_chars (opcode, PAR_NOP_INSN, 2);
      opcode_address += 2;
      extension = 4;
      displacement = & opcode[3];
      break;
    default :
      abort ();
    }

  if (S_GET_SEGMENT (fragP->fr_symbol) != sec)
    {
      /* symbol must be resolved by linker */
      if (fragP->fr_offset & 3)
	as_warn (_("Addend to unresolved symbol not on word boundary."));
      addend = fragP->fr_offset >> 2;
    }
  else
    {
      /* Address we want to reach in file space.  */
      target_address = S_GET_VALUE (fragP->fr_symbol) + fragP->fr_offset;
      target_address += symbol_get_frag (fragP->fr_symbol)->fr_address;
      addend = (target_address - (opcode_address & -4)) >> 2;
    }

  /* Create a relocation for symbols that must be resolved by the linker.
     Otherwise output the completed insn.  */

  if (S_GET_SEGMENT (fragP->fr_symbol) != sec)
    {
      assert (fragP->fr_subtype != 1);
      assert (fragP->fr_cgen.insn != 0);
      gas_cgen_record_fixup (fragP,
			     /* Offset of branch insn in frag.  */
			     fragP->fr_fix + extension - 4,
			     fragP->fr_cgen.insn,
			     4 /*length*/,
			     /* FIXME: quick hack */
#if 0
			     CGEN_OPERAND_ENTRY (fragP->fr_cgen.opindex),
#else
			     CGEN_OPERAND_ENTRY (FR30_OPERAND_DISP24),
#endif
			     fragP->fr_cgen.opinfo,
			     fragP->fr_symbol, fragP->fr_offset);
    }

#define SIZE_FROM_RELAX_STATE(n) ((n) == 1 ? 1 : 3)

  md_number_to_chars (displacement, (valueT) addend,
		      SIZE_FROM_RELAX_STATE (fragP->fr_subtype));

  fragP->fr_fix += extension;
#endif
}

/* Functions concerning relocs.  */

/* The location from which a PC relative jump should be calculated,
   given a PC relative reloc.  */

long
md_pcrel_from_section (fixP, sec)
     fixS * fixP;
     segT   sec;
{
  if (fixP->fx_addsy != (symbolS *) NULL
      && (! S_IS_DEFINED (fixP->fx_addsy)
	  || S_GET_SEGMENT (fixP->fx_addsy) != sec))
    {
      /* The symbol is undefined (or is defined but not in this section).
	 Let the linker figure it out.  */
      return 0;
    }

  return (fixP->fx_frag->fr_address + fixP->fx_where) & ~1;
}

/* Return the bfd reloc type for OPERAND of INSN at fixup FIXP.
   Returns BFD_RELOC_NONE if no reloc type can be found.
   *FIXP may be modified if desired.  */

bfd_reloc_code_real_type
md_cgen_lookup_reloc (insn, operand, fixP)
     const CGEN_INSN *    insn;
     const CGEN_OPERAND * operand;
     fixS *               fixP;
{
  switch (operand->type)
    {
    case FR30_OPERAND_LABEL9:  fixP->fx_pcrel = 1; return BFD_RELOC_FR30_9_PCREL;
    case FR30_OPERAND_LABEL12: fixP->fx_pcrel = 1; return BFD_RELOC_FR30_12_PCREL;
    case FR30_OPERAND_DISP10:  return BFD_RELOC_FR30_10_IN_8;
    case FR30_OPERAND_DISP9:   return BFD_RELOC_FR30_9_IN_8;
    case FR30_OPERAND_DISP8:   return BFD_RELOC_FR30_8_IN_8;
    case FR30_OPERAND_UDISP6:  return BFD_RELOC_FR30_6_IN_4;
    case FR30_OPERAND_I8:      return BFD_RELOC_8;
    case FR30_OPERAND_I32:     return BFD_RELOC_FR30_48;
    case FR30_OPERAND_I20:     return BFD_RELOC_FR30_20;
    default : /* avoid -Wall warning */
      break;
    }

  return BFD_RELOC_NONE;
}

/* See whether we need to force a relocation into the output file.
   This is used to force out switch and PC relative relocations when
   relaxing.  */

int
fr30_force_relocation (fix)
     fixS * fix;
{
  if (   fix->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fix->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    return 1;

  return 0;
}

/* Write a value out to the object file, using the appropriate endianness.  */

void
md_number_to_chars (buf, val, n)
     char * buf;
     valueT val;
     int    n;
{
  number_to_chars_bigendian (buf, val, n);
}

/* Turn a string in input_line_pointer into a floating point constant of type
   type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
   emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
*/

/* Equal to MAX_PRECISION in atof-ieee.c */
#define MAX_LITTLENUMS 6

char *
md_atof (type, litP, sizeP)
     char   type;
     char * litP;
     int *  sizeP;
{
  int              i;
  int              prec;
  LITTLENUM_TYPE   words [MAX_LITTLENUMS];
  char *           t;
  char *           atof_ieee ();

  switch (type)
    {
    case 'f':
    case 'F':
    case 's':
    case 'S':
      prec = 2;
      break;

    case 'd':
    case 'D':
    case 'r':
    case 'R':
      prec = 4;
      break;

   /* FIXME: Some targets allow other format chars for bigger sizes here.  */

    default:
      * sizeP = 0;
      return _("Bad call to md_atof()");
    }

  t = atof_ieee (input_line_pointer, type, words);
  if (t)
    input_line_pointer = t;
  * sizeP = prec * sizeof (LITTLENUM_TYPE);

  for (i = 0; i < prec; i++)
    {
      md_number_to_chars (litP, (valueT) words[i],
			  sizeof (LITTLENUM_TYPE));
      litP += sizeof (LITTLENUM_TYPE);
    }

  return 0;
}

/* Worker function for fr30_is_colon_insn().  */
static char
restore_colon (advance_i_l_p_by)
     int advance_i_l_p_by;
{
  char c;

  /* Restore the colon, and advance input_line_pointer to
     the end of the new symbol.  */
  * input_line_pointer = ':';
  input_line_pointer += advance_i_l_p_by;
  c = * input_line_pointer;
  * input_line_pointer = 0;

  return c;
}

/* Determines if the symbol starting at START and ending in
   a colon that was at the location pointed to by INPUT_LINE_POINTER
   (but which has now been replaced bu a NUL) is in fact an
   LDI:8, LDI:20, LDI:32, CALL:D. JMP:D, RET:D or Bcc:D instruction.
   If it is, then it restores the colon, advances INPUT_LINE_POINTER
   to the real end of the instruction/symbol, and returns the character
   that really terminated the symbol.  Otherwise it returns 0.  */
char
fr30_is_colon_insn (start)
     char *  start;
{
  char * i_l_p = input_line_pointer;

  /* Check to see if the symbol parsed so far is 'ldi'  */
  if (   (start[0] != 'l' && start[0] != 'L')
      || (start[1] != 'd' && start[1] != 'D')
      || (start[2] != 'i' && start[2] != 'I')
      || start[3] != 0)
    {
      /* Nope - check to see a 'd' follows the colon.  */
      if (   (i_l_p[1] == 'd' || i_l_p[1] == 'D')
	  && (i_l_p[2] == ' ' || i_l_p[2] == '\t' || i_l_p[2] == '\n'))
	{
	  /* Yup - it might be delay slot instruction.  */
	  int           i;
	  static char * delay_insns [] =
	  {
	    "call", "jmp", "ret", "bra", "bno",
	    "beq",  "bne", "bc",  "bnc", "bn",
	    "bp",   "bv",  "bnv", "blt", "bge",
	    "ble",  "bgt", "bls", "bhi"
	  };

	  for (i = sizeof (delay_insns) / sizeof (delay_insns[0]); i--;)
	    {
	      char * insn = delay_insns[i];
	      int    len  = strlen (insn);

	      if (start [len] != 0)
		continue;

	      while (len --)
		if (tolower (start [len]) != insn [len])
		  break;

	      if (len == -1)
		return restore_colon (1);
	    }
	}

      /* Nope - it is a normal label.  */
      return 0;
    }

  /* Check to see if the text following the colon is '8' */
  if (i_l_p[1] == '8' && (i_l_p[2] == ' ' || i_l_p[2] == '\t'))
    return restore_colon (2);

  /* Check to see if the text following the colon is '20' */
  else if (i_l_p[1] == '2' && i_l_p[2] =='0' && (i_l_p[3] == ' ' || i_l_p[3] == '\t'))
    return restore_colon (3);

  /* Check to see if the text following the colon is '32' */
  else if (i_l_p[1] == '3' && i_l_p[2] =='2' && (i_l_p[3] == ' ' || i_l_p[3] == '\t'))
    return restore_colon (3);

  return 0;
}

boolean
fr30_fix_adjustable (fixP)
   fixS * fixP;
{
  if (fixP->fx_addsy == NULL)
    return 1;

#if 0
  /* Prevent all adjustments to global symbols.  */
  if (S_IS_EXTERN (fixP->fx_addsy))
    return 0;

  if (S_IS_WEAK (fixP->fx_addsy))
    return 0;
#endif

  /* We need the symbol name for the VTABLE entries */
  if (   fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    return 0;

  return 1;
}