tc-alpha.c

基于4个mips核的noc设计

/* Round up a section's size to the appropriate boundary.  */

valueT
md_section_align (seg, size)
     segT seg;
     valueT size;
{
  int align = bfd_get_section_alignment (stdoutput, seg);
  valueT mask = ((valueT) 1 << align) - 1;

  return (size + mask) & ~mask;
}

/* 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

extern char *vax_md_atof PARAMS ((int, char *, int *));

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

  switch (type)
    {
      /* VAX floats */
    case 'G':
      /* VAX md_atof doesn't like "G" for some reason.  */
      type = 'g';
    case 'F':
    case 'D':
      return vax_md_atof (type, litP, sizeP);

      /* IEEE floats */
    case 'f':
      prec = 2;
      break;

    case 'd':
      prec = 4;
      break;

    case 'x':
    case 'X':
      prec = 6;
      break;

    case 'p':
    case 'P':
      prec = 6;
      break;

    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 (wordP = words + prec - 1; prec--;)
    {
      md_number_to_chars (litP, (long) (*wordP--), sizeof (LITTLENUM_TYPE));
      litP += sizeof (LITTLENUM_TYPE);
    }

  return 0;
}

/* Take care of the target-specific command-line options.  */

int
md_parse_option (c, arg)
     int c;
     char *arg;
{
  switch (c)
    {
    case 'F':
      alpha_nofloats_on = 1;
      break;

    case OPTION_32ADDR:
      alpha_addr32_on = 1;
      break;

    case 'g':
      alpha_debug = 1;
      break;

    case 'G':
      g_switch_value = atoi (arg);
      break;

    case 'm':
      {
	const struct cpu_type *p;
	for (p = cpu_types; p->name; ++p)
	  if (strcmp (arg, p->name) == 0)
	    {
	      alpha_target_name = p->name, alpha_target = p->flags;
	      goto found;
	    }
	as_warn (_("Unknown CPU identifier `%s'"), arg);
      found:;
      }
      break;

#ifdef OBJ_EVAX
    case '+':			/* For g++.  Hash any name > 63 chars long.  */
      alpha_flag_hash_long_names = 1;
      break;

    case 'H':			/* Show new symbol after hash truncation */
      alpha_flag_show_after_trunc = 1;
      break;

    case 'h':			/* for gnu-c/vax compatibility.  */
      break;
#endif

    case OPTION_RELAX:
      alpha_flag_relax = 1;
      break;

#ifdef OBJ_ELF
    case OPTION_MDEBUG:
      alpha_flag_mdebug = 1;
      break;
    case OPTION_NO_MDEBUG:
      alpha_flag_mdebug = 0;
      break;
#endif

    default:
      return 0;
    }

  return 1;
}

/* Print a description of the command-line options that we accept.  */

void
md_show_usage (stream)
     FILE *stream;
{
  fputs (_("\
Alpha options:\n\
-32addr			treat addresses as 32-bit values\n\
-F			lack floating point instructions support\n\
-mev4 | -mev45 | -mev5 | -mev56 | -mpca56 | -mev6 | -mall\n\
			specify variant of Alpha architecture\n\
-m21064 | -m21066 | -m21164 | -m21164a | -m21164pc | -m21264\n\
			these variants include PALcode opcodes\n"),
	stream);
#ifdef OBJ_EVAX
  fputs (_("\
VMS options:\n\
-+			hash encode (don't truncate) names longer than 64 characters\n\
-H			show new symbol after hash truncation\n"),
	stream);
#endif
}

/* Decide from what point a pc-relative relocation is relative to,
   relative to the pc-relative fixup.  Er, relatively speaking.  */

long
md_pcrel_from (fixP)
     fixS *fixP;
{
  valueT addr = fixP->fx_where + fixP->fx_frag->fr_address;
  switch (fixP->fx_r_type)
    {
    case BFD_RELOC_ALPHA_GPDISP:
    case BFD_RELOC_ALPHA_GPDISP_HI16:
    case BFD_RELOC_ALPHA_GPDISP_LO16:
      return addr;
    default:
      return fixP->fx_size + addr;
    }
}

/* Attempt to simplify or even eliminate a fixup.  The return value is
   ignored; perhaps it was once meaningful, but now it is historical.
   To indicate that a fixup has been eliminated, set fixP->fx_done.

   For ELF, here it is that we transform the GPDISP_HI16 reloc we used
   internally into the GPDISP reloc used externally.  We had to do
   this so that we'd have the GPDISP_LO16 reloc as a tag to compute
   the distance to the "lda" instruction for setting the addend to
   GPDISP.  */

int
md_apply_fix (fixP, valueP)
     fixS *fixP;
     valueT *valueP;
{
  char * const fixpos = fixP->fx_frag->fr_literal + fixP->fx_where;
  valueT value = *valueP;
  unsigned image, size;

  switch (fixP->fx_r_type)
    {
      /* The GPDISP relocations are processed internally with a symbol
	 referring to the current function; we need to drop in a value
	 which, when added to the address of the start of the function,
	 gives the desired GP.  */
    case BFD_RELOC_ALPHA_GPDISP_HI16:
      {
	fixS *next = fixP->fx_next;
	assert (next->fx_r_type == BFD_RELOC_ALPHA_GPDISP_LO16);

	fixP->fx_offset = (next->fx_frag->fr_address + next->fx_where
			   - fixP->fx_frag->fr_address - fixP->fx_where);

	value = (value - sign_extend_16 (value)) >> 16;
      }
#ifdef OBJ_ELF
      fixP->fx_r_type = BFD_RELOC_ALPHA_GPDISP;
#endif
      goto do_reloc_gp;

    case BFD_RELOC_ALPHA_GPDISP_LO16:
      value = sign_extend_16 (value);
      fixP->fx_offset = 0;
#ifdef OBJ_ELF
      fixP->fx_done = 1;
#endif

    do_reloc_gp:
      fixP->fx_addsy = section_symbol (now_seg);
      md_number_to_chars (fixpos, value, 2);
      break;

    case BFD_RELOC_16:
      if (fixP->fx_pcrel)
	fixP->fx_r_type = BFD_RELOC_16_PCREL;
      size = 2;
      goto do_reloc_xx;
    case BFD_RELOC_32:
      if (fixP->fx_pcrel)
	fixP->fx_r_type = BFD_RELOC_32_PCREL;
      size = 4;
      goto do_reloc_xx;
    case BFD_RELOC_64:
      if (fixP->fx_pcrel)
	fixP->fx_r_type = BFD_RELOC_64_PCREL;
      size = 8;
    do_reloc_xx:
      if (fixP->fx_pcrel == 0 && fixP->fx_addsy == 0)
	{
	  md_number_to_chars (fixpos, value, size);
	  goto done;
	}
      return 1;

#ifdef OBJ_ECOFF
    case BFD_RELOC_GPREL32:
      assert (fixP->fx_subsy == alpha_gp_symbol);
      fixP->fx_subsy = 0;
      /* FIXME: inherited this obliviousness of `value' -- why? */
      md_number_to_chars (fixpos, -alpha_gp_value, 4);
      break;
#endif
#ifdef OBJ_ELF
    case BFD_RELOC_GPREL32:
      return 1;
#endif

    case BFD_RELOC_23_PCREL_S2:
      if (fixP->fx_pcrel == 0 && fixP->fx_addsy == 0)
	{
	  image = bfd_getl32 (fixpos);
	  image = (image & ~0x1FFFFF) | ((value >> 2) & 0x1FFFFF);
	  goto write_done;
	}
      return 1;

    case BFD_RELOC_ALPHA_HINT:
      if (fixP->fx_pcrel == 0 && fixP->fx_addsy == 0)
	{
	  image = bfd_getl32 (fixpos);
	  image = (image & ~0x3FFF) | ((value >> 2) & 0x3FFF);
	  goto write_done;
	}
      return 1;

#ifdef OBJ_ECOFF
    case BFD_RELOC_ALPHA_LITERAL:
      md_number_to_chars (fixpos, value, 2);
      return 1;

    case BFD_RELOC_ALPHA_LITUSE:
      return 1;
#endif
#ifdef OBJ_ELF
    case BFD_RELOC_ALPHA_ELF_LITERAL:
    case BFD_RELOC_ALPHA_LITUSE:
      return 1;
#endif
#ifdef OBJ_EVAX
    case BFD_RELOC_ALPHA_LINKAGE:
    case BFD_RELOC_ALPHA_CODEADDR:
      return 1;
#endif

#ifdef RELOC_OP_P
    case BFD_RELOC_ALPHA_USER_LITERAL:
    case BFD_RELOC_ALPHA_USER_LITUSE_BASE:
    case BFD_RELOC_ALPHA_USER_LITUSE_BYTOFF:
    case BFD_RELOC_ALPHA_USER_LITUSE_JSR:
      return 1;

    case BFD_RELOC_ALPHA_USER_GPDISP:
    case BFD_RELOC_ALPHA_USER_GPRELHIGH:
    case BFD_RELOC_ALPHA_USER_GPRELLOW:
      abort ();
#endif

    case BFD_RELOC_VTABLE_INHERIT:
    case BFD_RELOC_VTABLE_ENTRY:
      return 1;

    default:
      {
	const struct alpha_operand *operand;

	if ((int) fixP->fx_r_type >= 0)
	  as_fatal (_("unhandled relocation type %s"),
		    bfd_get_reloc_code_name (fixP->fx_r_type));

	assert (-(int) fixP->fx_r_type < (int) alpha_num_operands);
	operand = &alpha_operands[-(int) fixP->fx_r_type];

	/* The rest of these fixups only exist internally during symbol
	   resolution and have no representation in the object file.
	   Therefore they must be completely resolved as constants.  */

	if (fixP->fx_addsy != 0
	    && S_GET_SEGMENT (fixP->fx_addsy) != absolute_section)
	  as_bad_where (fixP->fx_file, fixP->fx_line,
			_("non-absolute expression in constant field"));

	image = bfd_getl32 (fixpos);
	image = insert_operand (image, operand, (offsetT) value,
				fixP->fx_file, fixP->fx_line);
      }
      goto write_done;
    }

  if (fixP->fx_addsy != 0 || fixP->fx_pcrel != 0)
    return 1;
  else
    {
      as_warn_where (fixP->fx_file, fixP->fx_line,
		     _("type %d reloc done?\n"), (int) fixP->fx_r_type);
      goto done;
    }

write_done:
  md_number_to_chars (fixpos, image, 4);

done:
  fixP->fx_done = 1;
  return 0;
}

/*
 * Look for a register name in the given symbol.
 */

symbolS *
md_undefined_symbol (name)
     char *name;
{
  if (*name == '$')
    {
      int is_float = 0, num;

      switch (*++name)
	{
	case 'f':
	  if (name[1] == 'p' && name[2] == '\0')
	    return alpha_register_table[AXP_REG_FP];
	  is_float = 32;
	  /* FALLTHRU */

	case 'r':
	  if (!isdigit (*++name))
	    break;
	  /* FALLTHRU */

	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':
	  if (name[1] == '\0')
	    num = name[0] - '0';
	  else if (name[0] != '0' && isdigit (name[1]) && name[2] == '\0')
	    {
	      num = (name[0] - '0') * 10 + name[1] - '0';
	      if (num >= 32)
		break;
	    }
	  else
	    break;

	  if (!alpha_noat_on && (num + is_float) == AXP_REG_AT)
	    as_warn (_("Used $at without \".set noat\""));
	  return alpha_register_table[num + is_float];

	case 'a':
	  if (name[1] == 't' && name[2] == '\0')
	    {
	      if (!alpha_noat_on)
		as_warn (_("Used $at without \".set noat\""));
	      return alpha_register_table[AXP_REG_AT];
	    }
	  break;

	case 'g':
	  if (name[1] == 'p' && name[2] == '\0')
	    return alpha_register_table[alpha_gp_register];
	  break;

	case 's':
	  if (name[1] == 'p' && name[2] == '\0')
	    return alpha_register_table[AXP_REG_SP];
	  break;
	}
    }
  return NULL;
}

#ifdef OBJ_ECOFF
/* @@@ Magic ECOFF bits.  */

void
alpha_frob_ecoff_data ()
{
  select_gp_value ();
  /* $zero and $f31 are read-only */
  alpha_gprmask &= ~1;
  alpha_fprmask &= ~1;
}
#endif

/* Hook to remember a recently defined label so that the auto-align
   code can adjust the symbol after we know what alignment will be
   required.  */

void
alpha_define_label (sym)
     symbolS *sym;
{
  alpha_insn_label = sym;
}

/* Return true if we must always emit a reloc for a type and false if
   there is some hope of resolving it a assembly time.  */

int
alpha_force_relocation (f)
     fixS *f;
{