tc-mcore.c

基于4个mips核的noc设计

    case OPTION_JSRI2BSR_OFF: do_jsri2bsr = 0;   break;
    case OPTION_SIFILTER_ON:  sifilter_mode = 1; break;
    case OPTION_SIFILTER_OFF: sifilter_mode = 0; break;
    default:                  return 0;
    }

  return 1;
}

void
md_show_usage (stream)
     FILE * stream;
{
  fprintf (stream, _("\
MCORE specific options:\n\
  -{no-}jsri2bsr	  {dis}able jsri to bsr transformation (def: dis)\n\
  -{no-}sifilter	  {dis}able silicon filter behavior (def: dis)\n\
  -cpu=[210|340]          select CPU type\n\
  -EB                     assemble for a big endian system (default)\n\
  -EL                     assemble for a little endian system\n"));
}

int md_short_jump_size;

void
md_create_short_jump (ptr, from_Nddr, to_Nddr, frag, to_symbol)
     char * ptr;
     addressT from_Nddr;
     addressT to_Nddr;
     fragS * frag;
     symbolS * to_symbol;
{
  as_fatal (_("failed sanity check: short_jump"));
}

void
md_create_long_jump (ptr, from_Nddr, to_Nddr, frag, to_symbol)
     char * ptr;
     addressT from_Nddr;
     addressT to_Nddr;
     fragS * frag;
     symbolS * to_symbol;
{
  as_fatal (_("failed sanity check: long_jump"));
}

/* Called after relaxing, change the frags so they know how big they are.  */
void
md_convert_frag (abfd, sec, fragP)
     bfd * abfd;
     segT sec;
     register fragS * fragP;
{
  unsigned char * buffer;
  int targ_addr = S_GET_VALUE (fragP->fr_symbol) + fragP->fr_offset;

  buffer = (unsigned char *) (fragP->fr_fix + fragP->fr_literal);
  targ_addr += symbol_get_frag (fragP->fr_symbol)->fr_address;

  switch (fragP->fr_subtype)
    {
    case C (COND_JUMP, DISP12):
    case C (UNCD_JUMP, DISP12):
      {
	/* Get the address of the end of the instruction.  */
	int next_inst = fragP->fr_fix + fragP->fr_address + 2;
	unsigned char t0;
	int disp = targ_addr - next_inst;

	if (disp & 1)
	  as_bad (_("odd displacement at %x"), next_inst - 2);

	disp >>= 1;

	if (! target_big_endian)
	  {
	    t0 = buffer[1] & 0xF8;

	    md_number_to_chars (buffer, disp, 2);

	    buffer[1] = (buffer[1] & 0x07) | t0;
	  }
	else
	  {
	    t0 = buffer[0] & 0xF8;

	    md_number_to_chars (buffer, disp, 2);

	    buffer[0] = (buffer[0] & 0x07) | t0;
	  }

	fragP->fr_fix += 2;
      }
      break;

    case C (COND_JUMP, DISP32):
    case C (COND_JUMP, UNDEF_WORD_DISP):
      {
	/* A conditional branch wont fit into 12 bits so:
	 *	b!cond	1f
	 *	jmpi	0f
	 *	.align 2
	 * 0:	.long disp
	 * 1:
	 *
	 * if the b!cond is 4 byte aligned, the literal which would
	 * go at x+4 will also be aligned.
	 */
	int first_inst = fragP->fr_fix + fragP->fr_address;
	int needpad = (first_inst & 3);

	if (! target_big_endian)
	  buffer[1] ^= 0x08;
	else
	  buffer[0] ^= 0x08;	/* Toggle T/F bit */

	buffer[2] = INST_BYTE0 (MCORE_INST_JMPI);	/* Build jmpi */
	buffer[3] = INST_BYTE1 (MCORE_INST_JMPI);

	if (needpad)
	  {
	    if (! target_big_endian)
	      {
		buffer[0] = 4;	/* branch over jmpi, pad, and ptr */
		buffer[2] = 1;	/* jmpi offset of 1 gets the pointer */
	      }
	    else
	      {
		buffer[1] = 4;	/* branch over jmpi, pad, and ptr */
		buffer[3] = 1;	/* jmpi offset of 1 gets the pointer */
	      }

	    buffer[4] = 0;	/* alignment/pad */
	    buffer[5] = 0;
	    buffer[6] = 0;	/* space for 32 bit address */
	    buffer[7] = 0;
	    buffer[8] = 0;
	    buffer[9] = 0;

	    /* Make reloc for the long disp */
	    fix_new (fragP, fragP->fr_fix + 6, 4,
		     fragP->fr_symbol, fragP->fr_offset, 0, BFD_RELOC_32);

	    fragP->fr_fix += C32_LEN;
	  }
	else
	  {
	    /* See comment below about this given gas' limitations for
	       shrinking the fragment. '3' is the amount of code that
	       we inserted here, but '4' is right for the space we reserved
	       for this fragment.  */
	    if (! target_big_endian)
	      {
		buffer[0] = 3;	/* branch over jmpi, and ptr */
		buffer[2] = 0;	/* jmpi offset of 0 gets the pointer */
	      }
	    else
	      {
		buffer[1] = 3;	/* branch over jmpi, and ptr */
		buffer[3] = 0;	/* jmpi offset of 0 gets the pointer */
	      }

	    buffer[4] = 0;	/* space for 32 bit address */
	    buffer[5] = 0;
	    buffer[6] = 0;
	    buffer[7] = 0;

	    /* Make reloc for the long disp.  */
	    fix_new (fragP, fragP->fr_fix + 4, 4,
		     fragP->fr_symbol, fragP->fr_offset, 0, BFD_RELOC_32);
	    fragP->fr_fix += C32_LEN;

	    /* Frag is actually shorter (see the other side of this ifdef)
	       but gas isn't prepared for that.  We have to re-adjust
	       the branch displacement so that it goes beyond the
	       full length of the fragment, not just what we actually
	       filled in.  */
	    if (! target_big_endian)
	      buffer[0] = 4;	/* jmpi, ptr, and the 'tail pad' */
	    else
	      buffer[1] = 4;	/* jmpi, ptr, and the 'tail pad' */
	  }
      }
      break;

    case C (UNCD_JUMP, DISP32):
    case C (UNCD_JUMP, UNDEF_WORD_DISP):
      {
	/* An unconditional branch will not fit in 12 bits, make code which
	   looks like:
	  	jmpi	0f
	  	.align 2
	     0:	.long disp
	   we need a pad if "first_inst" is 4 byte aligned.
	   [because the natural literal place is x + 2]  */
	int first_inst = fragP->fr_fix + fragP->fr_address;
	int needpad = !(first_inst & 3);

	buffer[0] = INST_BYTE0 (MCORE_INST_JMPI);	/* Build jmpi */
	buffer[1] = INST_BYTE1 (MCORE_INST_JMPI);

	if (needpad)
	  {
	    if (! target_big_endian)
	      buffer[0] = 1;	/* jmpi offset of 1 since padded */
	    else
	      buffer[1] = 1;	/* jmpi offset of 1 since padded */
	    buffer[2] = 0;	/* alignment */
	    buffer[3] = 0;
	    buffer[4] = 0;	/* space for 32 bit address */
	    buffer[5] = 0;
	    buffer[6] = 0;
	    buffer[7] = 0;

	    /* Make reloc for the long disp.  */
	    fix_new (fragP, fragP->fr_fix + 4, 4,
		     fragP->fr_symbol, fragP->fr_offset, 0, BFD_RELOC_32);

	    fragP->fr_fix += U32_LEN;
	  }
	else
	  {
	    if (! target_big_endian)
	      buffer[0] = 0;	/* jmpi offset of 0 if no pad */
	    else
	      buffer[1] = 0;	/* jmpi offset of 0 if no pad */
	    buffer[2] = 0;	/* space for 32 bit address */
	    buffer[3] = 0;
	    buffer[4] = 0;
	    buffer[5] = 0;

	    /* Make reloc for the long disp.  */
	    fix_new (fragP, fragP->fr_fix + 2, 4,
		     fragP->fr_symbol, fragP->fr_offset, 0, BFD_RELOC_32);
	    fragP->fr_fix += U32_LEN;
	  }
      }
      break;

    default:
      abort ();
    }
}

/* Applies the desired value to the specified location.
   Also sets up addends for 'rela' type relocations.  */
int
md_apply_fix3 (fixP, valp, segment)
     fixS *   fixP;
     valueT * valp;
     segT     segment;
{
  char *       buf  = fixP->fx_where + fixP->fx_frag->fr_literal;
  char *       file = fixP->fx_file ? fixP->fx_file : _("unknown");
  const char * symname;
  /* Note: use offsetT because it is signed, valueT is unsigned.  */
  offsetT      val  = (offsetT) * valp;

  symname = fixP->fx_addsy ? S_GET_NAME (fixP->fx_addsy) : _("<unknown>");
  /* Save this for the addend in the relocation record.  */
  fixP->fx_addnumber = val;

  /* If the fix is relative to a symbol which is not defined, or not
     in the same segment as the fix, we cannot resolve it here.  */
  if (fixP->fx_addsy != NULL
      && (   ! S_IS_DEFINED (fixP->fx_addsy)
	  || (S_GET_SEGMENT (fixP->fx_addsy) != segment)))
    {
      fixP->fx_done = 0;
#ifdef OBJ_ELF
      /* For ELF we can just return and let the reloc that will be generated
	 take care of everything.  For COFF we still have to insert 'val'
	 into the insn since the addend field will be ignored.  */
      return 0;
#endif
    }
  else
    fixP->fx_done = 1;

  switch (fixP->fx_r_type)
    {
    case BFD_RELOC_MCORE_PCREL_IMM11BY2:     /* second byte of 2 byte opcode */
      if ((val & 1) != 0)
	as_bad_where (file, fixP->fx_line,
		      _("odd distance branch (0x%x bytes)"), val);
      val /= 2;
      if (((val & ~0x3ff) != 0) && ((val | 0x3ff) != -1))
	as_bad_where (file, fixP->fx_line,
		      _("pcrel for branch to %s too far (0x%x)"),
		      symname, val);
      if (target_big_endian)
	{
	  buf[0] |= ((val >> 8) & 0x7);
	  buf[1] |= (val & 0xff);
	}
      else
	{
	  buf[1] |= ((val >> 8) & 0x7);
	  buf[0] |= (val & 0xff);
	}
      break;

    case BFD_RELOC_MCORE_PCREL_IMM8BY4:	/* lower 8 bits of 2 byte opcode */
      val += 3;
      val /= 4;
      if (val & ~0xff)
	as_bad_where (file, fixP->fx_line,
		      _("pcrel for lrw/jmpi/jsri to %s too far (0x%x)"),
		      symname, val);
      else if (! target_big_endian)
	buf[0] |= (val & 0xff);
      else
	buf[1] |= (val & 0xff);
      break;

    case BFD_RELOC_MCORE_PCREL_IMM4BY2:	/* loopt instruction */
      if ((val < -32) || (val > -2))
	as_bad_where (file, fixP->fx_line,
		      _("pcrel for loopt too far (0x%x)"), val);
      val /= 2;
      if (! target_big_endian)
	buf[0] |= (val & 0xf);
      else
	buf[1] |= (val & 0xf);
      break;

    case BFD_RELOC_MCORE_PCREL_JSR_IMM11BY2:
      /* Conditional linker map jsri to bsr.  */
      /* If its a local target and close enough, fix it.
         NB: >= -2k for backwards bsr; < 2k for forwards...  */
      if (fixP->fx_addsy == 0 && val >= -2048  && val < 2048)
	{
	  long nval = (val / 2) & 0x7ff;
	  nval |= MCORE_INST_BSR;

	  /* REPLACE the instruction, don't just modify it.  */
	  buf[0] = INST_BYTE0 (nval);
	  buf[1] = INST_BYTE1 (nval);
	}
      else
	fixP->fx_done = 0;
      break;

    case BFD_RELOC_MCORE_PCREL_32:
    case BFD_RELOC_VTABLE_INHERIT:
    case BFD_RELOC_VTABLE_ENTRY:
      fixP->fx_done = 0;
      break;

    default:
      if (fixP->fx_addsy != NULL)
	{
	  /* If the fix is an absolute reloc based on a symbol's
	     address, then it cannot be resolved until the final link.  */
	  fixP->fx_done = 0;
	}
#ifdef OBJ_ELF
      else
#endif
	{
	  if (fixP->fx_size == 4)
	    ;
	  else if (fixP->fx_size == 2 && val >= -32768 && val <= 32767)
	    ;
	  else if (fixP->fx_size == 1 && val >= -256 && val <= 255)
	    ;
	  else
	    abort ();
	  md_number_to_chars (buf, val, fixP->fx_size);
	}
      break;
    }

  return 0; /* Return value is ignored.  */
}

void
md_operand (expressionP)
     expressionS * expressionP;
{
  /* Ignore leading hash symbol, if poresent.  */
  if (* input_line_pointer == '#')
    {
      input_line_pointer ++;
      expression (expressionP);
    }
}

int md_long_jump_size;

/* Called just before address relaxation, return the length
   by which a fragment must grow to reach it's destination.  */
int
md_estimate_size_before_relax (fragP, segment_type)
     register fragS * fragP;
     register segT segment_type;
{
  switch (fragP->fr_subtype)
    {
    default:
      abort ();

    case C (UNCD_JUMP, UNDEF_DISP):
      /* Used to be a branch to somewhere which was unknown.  */
      if (!fragP->fr_symbol)
	{
	  fragP->fr_subtype = C (UNCD_JUMP, DISP12);
	}
      else if (S_GET_SEGMENT (fragP->fr_symbol) == segment_type)
	{
	  fragP->fr_subtype = C (UNCD_JUMP, DISP12);
	}
      else
	{
	  fragP->fr_subtype = C (UNCD_JUMP, UNDEF_WORD_DISP);
	}
      break;

    case C (COND_JUMP, UNDEF_DISP):
      /* Used to be a branch to somewhere which was unknown.  */
      if (fragP->fr_symbol
	  && S_GET_SEGMENT (fragP->fr_symbol) == segment_type)
	{
	  /* Got a symbol and it's defined in this segment, become byte
	     sized - maybe it will fix up */
	  fragP->fr_subtype = C (COND_JUMP, DISP12);
	}
      else if (fragP->fr_symbol)
	{
	  /* Its got a segment, but its not ours, so it will always be long.  */
	  fragP->fr_subtype = C (COND_JUMP, UNDEF_WORD_DISP);
	}
      else
	{
	  /* We know the abs value.  */
	  fragP->fr_subtype = C (COND_JUMP, DISP12);
	}
      break;

    case C (UNCD_JUMP, DISP12):
    case C (UNCD_JUMP, DISP32):
    case C (UNCD_JUMP, UNDEF_WORD_DISP):
    case C (COND_JUMP, DISP12):
    case C (COND_JUMP, DISP32):
    case C (COND_JUMP, UNDEF_WORD_DISP):
      /* When relaxing a section for the second time, we don't need to
	 do anything besides return the current size.  */
      break;
    }

  return md_relax_table[fragP->fr_subtype].rlx_length;
}

/* Put number into target byte order.  */
void
md_number_to_chars (ptr, use, nbytes)
     char * ptr;
     valueT use;
     int nbytes;
{
  if (! target_big_endian)
    switch (nbytes)
      {
      case 4: ptr[3] = (use >> 24) & 0xff; /* fall through */
      case 3: ptr[2] = (use >> 16) & 0xff; /* fall through */
      case 2: ptr[1] = (use >>  8) & 0xff; /* fall through */
      case 1: ptr[0] = (use >>  0) & 0xff;    break;
      default: abort ();
      }
  else
    switch (nbytes)
      {
      case 4: *ptr++ = (use >> 24) & 0xff; /* fall through */
      case 3: *ptr++ = (use >> 16) & 0xff; /* fall through */
      case 2: *ptr++ = (use >>  8) & 0xff; /* fall through */
      case 1: *ptr++ = (use >>  0) & 0xff;    break;
      default: abort ();
      }
}

/* Round up a section size to the appropriate boundary.  */
valueT
md_section_align (segment, size)
     segT segment;
     valueT size;
{
  return size;			/* Byte alignment is fine */
}

/* 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;
{
#ifdef OBJ_ELF
  /* If the symbol is undefined or defined in another section
     we leave the add number alone for the linker to fix it later.
     Only account for the PC pre-bump (which is 2 bytes on the MCore).  */
  if (fixp->fx_addsy != (symbolS *) NULL
      && (! S_IS_DEFINED (fixp->fx_addsy)
	  || (S_GET_SEGMENT (fixp->fx_addsy) != sec)))

  {
    assert (fixp->fx_size == 2);	/* must be an insn */
    return fixp->fx_size;
  }
#endif

  /* The case where we are going to resolve things...  */
  return  fixp->fx_size + fixp->fx_where + fixp->fx_frag->fr_address;
}

#define F(SZ,PCREL)		(((SZ) << 1) + (PCREL))
#define MAP(SZ,PCREL,TYPE)	case F (SZ, PCREL): code = (TYPE); break

arelent *
tc_gen_reloc (section, fixp)
     asection * section;
     fixS * fixp;
{
  arelent * rel;
  bfd_reloc_code_real_type code;
  int handled = 0;

  switch (fixp->fx_r_type)
    {
      /* These confuse the size/pcrel macro approach.  */
    case BFD_RELOC_VTABLE_INHERIT:
    case BFD_RELOC_VTABLE_ENTRY:
    case BFD_RELOC_MCORE_PCREL_IMM4BY2:
    case BFD_RELOC_MCORE_PCREL_IMM8BY4:
    case BFD_RELOC_MCORE_PCREL_IMM11BY2:
    case BFD_RELOC_MCORE_PCREL_JSR_IMM11BY2:
    case BFD_RELOC_RVA:
      code = fixp->fx_r_type;
      break;

    default:
      switch (F (fixp->fx_size, fixp->fx_pcrel))
        {
          MAP (1, 0, BFD_RELOC_8);
          MAP (2, 0, BFD_RELOC_16);
          MAP (4, 0, BFD_RELOC_32);
          MAP (1, 1, BFD_RELOC_8_PCREL);
          MAP (2, 1, BFD_RELOC_16_PCREL);
          MAP (4, 1, BFD_RELOC_32_PCREL);
        default:
	  code = fixp->fx_r_type;
          as_bad (_("Can not do %d byte %srelocation"),
		  fixp->fx_size,
	          fixp->fx_pcrel ? _("pc-relative") : "");
        }
      break;
  }

  rel = (arelent *) xmalloc (sizeof (arelent));
  rel->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
  *rel->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy);
  rel->address = fixp->fx_frag->fr_address + fixp->fx_where;
  /* Always pass the addend along!  */
  rel->addend = fixp->fx_addnumber;

  rel->howto = bfd_reloc_type_lookup (stdoutput, code);

  if (rel->howto == NULL)
    {
      as_bad_where (fixp->fx_file, fixp->fx_line,
                    _("Cannot represent relocation type %s"),
                    bfd_get_reloc_code_name (code));

      /* Set howto to a garbage value so that we can keep going.  */
      rel->howto = bfd_reloc_type_lookup (stdoutput, BFD_RELOC_32);
      assert (rel->howto != NULL);
    }

  return rel;
}

#ifdef OBJ_ELF
/* 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
mcore_force_relocation (fix)
     fixS * fix;
{
  if (   fix->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fix->fx_r_type == BFD_RELOC_VTABLE_ENTRY
      || fix->fx_r_type == BFD_RELOC_RVA)
    return 1;

  return 0;
}

/* Return true if the fix can be handled by GAS, false if it must
   be passed through to the linker.  */
boolean
mcore_fix_adjustable (fixP)
   fixS * fixP;
{
  if (fixP->fx_addsy == NULL)
    return 1;

  /* 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;
}
#endif /* OBJ_ELF */