tc-ns32k.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 2,407 行 · 第 1/4 页

	  /* We can apply default, don't goof.  */
	  if (parse (desc->default_args, 1) != 1)
	    /* Check error in default.  */
	    as_fatal (_("Wrong numbers of operands in default, check ns32k-opcodes.h"));
	}
      else
	{
	  as_fatal (_("Wrong number of operands"));
	}
    }

  for (i = 0; i < IIF_ENTRIES; i++)
    /* Mark all entries as void.  */
    iif.iifP[i].type = 0;

  /* Build opcode iif-entry.  */
  iif.instr_size = desc->opcode_size / 8;
  IIF (1, 1, iif.instr_size, desc->opcode_seed, 0, 0, 0, 0, 0, 0, -1, 0);

  /* This call encodes operands to iif format.  */
  if (argc)
    {
      encode_operand (argc,
		      argv,
		      &desc->operands[0],
		      &suffix[0],
		      desc->im_size,
		      desc->opcode_size);
    }
  return recursive_level;
}

/* Convert iif to fragments.  From this point we start to dribble with
   functions in other files than this one.(Except hash.c) So, if it's
   possible to make an iif for an other CPU, you don't need to know
   what frags, relax, obstacks, etc is in order to port this
   assembler. You only need to know if it's possible to reduce your
   cpu-instruction to iif-format (takes some work) and adopt the other
   md_? parts according to given instructions Note that iif was
   invented for the clean ns32k`s architecure.  */

/* GAS for the ns32k has a problem. PC relative displacements are
   relative to the address of the opcode, not the address of the
   operand. We used to keep track of the offset between the operand
   and the opcode in pcrel_adjust for each frag and each fix. However,
   we get into trouble where there are two or more pc-relative
   operands and the size of the first one can't be determined. Then in
   the relax phase, the size of the first operand will change and
   pcrel_adjust will no longer be correct.  The current solution is
   keep a pointer to the frag with the opcode in it and the offset in
   that frag for each frag and each fix. Then, when needed, we can
   always figure out how far it is between the opcode and the pcrel
   object.  See also md_pcrel_adjust and md_fix_pcrel_adjust.  For
   objects not part of an instruction, the pointer to the opcode frag
   is always zero.  */

void
convert_iif ()
{
  int i;
  bit_fixS *j;
  fragS *inst_frag;
  unsigned int inst_offset;
  char *inst_opcode;
  char *memP;
  int l;
  int k;
  char type;
  char size = 0;
  int size_so_far;

  memP = frag_more (0);
  inst_opcode = memP;
  inst_offset = (memP - frag_now->fr_literal);
  inst_frag = frag_now;

  for (i = 0; i < IIF_ENTRIES; i++)
    {
      if (type = iif.iifP[i].type)
	{
	  /* The object exist, so handle it.  */
	  switch (size = iif.iifP[i].size)
	    {
	    case 42:
	      size = 0;
	      /* It's a bitfix that operates on an existing object.  */
	      if (iif.iifP[i].bit_fixP->fx_bit_base)
		/* Expand fx_bit_base to point at opcode.  */
		iif.iifP[i].bit_fixP->fx_bit_base = (long) inst_opcode;
	      /* Fall through.  */

	    case 8:		/* bignum or doublefloat */
	    case 1:
	    case 2:
	    case 3:
	    case 4:
	      /* The final size in objectmemory is known.  */
	      memP = frag_more(size);
	      j = iif.iifP[i].bit_fixP;

	      switch (type)
		{
		case 1:	/* The object is pure binary.  */
		  if (j || iif.iifP[i].pcrel)
		    {
		      fix_new_ns32k (frag_now,
				     (long) (memP - frag_now->fr_literal),
				     size,
				     0,
				     iif.iifP[i].object,
				     iif.iifP[i].pcrel,
				     iif.iifP[i].im_disp,
				     j,
				     iif.iifP[i].bsr,	/* sequent hack */
				     inst_frag, inst_offset);
		    }
		  else
		    {
		      /* Good, just put them bytes out.  */
		      switch (iif.iifP[i].im_disp)
			{
			case 0:
			  md_number_to_chars (memP, iif.iifP[i].object, size);
			  break;
			case 1:
			  md_number_to_disp (memP, iif.iifP[i].object, size);
			  break;
			default:
			  as_fatal (_("iif convert internal pcrel/binary"));
			}
		    }
		  break;

		case 2:
		  /* The object is a pointer at an expression, so
                     unpack it, note that bignums may result from the
                     expression.  */
		  evaluate_expr (&exprP, (char *) iif.iifP[i].object);
		  if (exprP.X_op == O_big || size == 8)
		    {
		      if ((k = exprP.X_add_number) > 0)
			{
			  /* We have a bignum ie a quad. This can only
                             happens in a long suffixed instruction.  */
			  if (k * 2 > size)
			    as_warn (_("Bignum too big for long"));

			  if (k == 3)
			    memP += 2;

			  for (l = 0; k > 0; k--, l += 2)
			    {
			      md_number_to_chars (memP + l,
						  generic_bignum[l >> 1],
						  sizeof (LITTLENUM_TYPE));
			    }
			}
		      else
			{
			  /* flonum.  */
			  LITTLENUM_TYPE words[4];

			  switch (size)
			    {
			    case 4:
			      gen_to_words (words, 2, 8);
			      md_number_to_imm (memP, (long) words[0],
						sizeof (LITTLENUM_TYPE));
			      md_number_to_imm (memP + sizeof (LITTLENUM_TYPE),
						(long) words[1],
						sizeof (LITTLENUM_TYPE));
			      break;
			    case 8:
			      gen_to_words (words, 4, 11);
			      md_number_to_imm (memP, (long) words[0],
						sizeof (LITTLENUM_TYPE));
			      md_number_to_imm (memP + sizeof (LITTLENUM_TYPE),
						(long) words[1],
						sizeof (LITTLENUM_TYPE));
			      md_number_to_imm ((memP + 2
						 * sizeof (LITTLENUM_TYPE)),
						(long) words[2],
						sizeof (LITTLENUM_TYPE));
			      md_number_to_imm ((memP + 3
						 * sizeof (LITTLENUM_TYPE)),
						(long) words[3],
						sizeof (LITTLENUM_TYPE));
			      break;
			    }
			}
		      break;
		    }
		  if (j ||
		      exprP.X_add_symbol ||
		      exprP.X_op_symbol ||
		      iif.iifP[i].pcrel)
		    {
		      /* The expression was undefined due to an
                         undefined label. Create a fix so we can fix
                         the object later.  */
		      exprP.X_add_number += iif.iifP[i].object_adjust;
		      fix_new_ns32k_exp (frag_now,
					 (long) (memP - frag_now->fr_literal),
					 size,
					 &exprP,
					 iif.iifP[i].pcrel,
					 iif.iifP[i].im_disp,
					 j,
					 iif.iifP[i].bsr,
					 inst_frag, inst_offset);
		    }
		  else
		    {
		      /* Good, just put them bytes out.  */
		      switch (iif.iifP[i].im_disp)
			{
			case 0:
			  md_number_to_imm (memP, exprP.X_add_number, size);
			  break;
			case 1:
			  md_number_to_disp (memP, exprP.X_add_number, size);
			  break;
			default:
			  as_fatal (_("iif convert internal pcrel/pointer"));
			}
		    }
		  break;
		default:
		  as_fatal (_("Internal logic error in iif.iifP[n].type"));
		}
	      break;

	    case 0:
	      /* Too bad, the object may be undefined as far as its
		 final nsize in object memory is concerned.  The size
		 of the object in objectmemory is not explicitly
		 given.  If the object is defined its length can be
		 determined and a fix can replace the frag.  */
	      {
		evaluate_expr (&exprP, (char *) iif.iifP[i].object);

		if ((exprP.X_add_symbol || exprP.X_op_symbol) &&
		    !iif.iifP[i].pcrel)
		  {
		    /* Size is unknown until link time so have to
                       allow 4 bytes.  */
		    size = 4;
		    memP = frag_more(size);
		    fix_new_ns32k_exp (frag_now,
				       (long) (memP - frag_now->fr_literal),
				       size,
				       &exprP,
				       0, /* never iif.iifP[i].pcrel, */
				       1, /* always iif.iifP[i].im_disp */
				       (bit_fixS *) 0, 0,
				       inst_frag,
				       inst_offset);
		    break;		/* exit this absolute hack */
		  }

		if (exprP.X_add_symbol || exprP.X_op_symbol)
		  {
		    /* Frag it.  */
		    if (exprP.X_op_symbol)
		      {
			/* We cant relax this case.  */
			as_fatal (_("Can't relax difference"));
		      }
		    else
		      {
			/* Size is not important.  This gets fixed by
			   relax, but we assume 0 in what follows.  */
			memP = frag_more(4); /* Max size.  */
			size = 0;

			{
			  fragS *old_frag = frag_now;
			  frag_variant (rs_machine_dependent,
					4, /* Max size.  */
					0, /* Size.  */
					IND (BRANCH, UNDEF), /* Expecting
                                                                the worst.  */
					exprP.X_add_symbol,
					exprP.X_add_number,
					inst_opcode);
			  frag_opcode_frag (old_frag) = inst_frag;
			  frag_opcode_offset (old_frag) = inst_offset;
			  frag_bsr (old_frag) = iif.iifP[i].bsr;
			}
		      }
		  }
		else
		  {
		    /* This duplicates code in md_number_to_disp.  */
		    if (-64 <= exprP.X_add_number && exprP.X_add_number <= 63)
		      {
			size = 1;
		      }
		    else
		      {
			if (-8192 <= exprP.X_add_number
			    && exprP.X_add_number <= 8191)
			  {
			    size = 2;
			  }
			else
			  {
			    if (-0x20000000 <= exprP.X_add_number
				&& exprP.X_add_number<=0x1fffffff)
			      {
				size = 4;
			      }
			    else
			      {
				as_warn (_("Displacement to large for :d"));
				size = 4;
			      }
			  }
		      }

		    memP = frag_more (size);
		    md_number_to_disp (memP, exprP.X_add_number, size);
		  }
	      }
	      break;

	    default:
	      as_fatal (_("Internal logic error in iif.iifP[].type"));
	    }
	}
    }
}

#ifdef BFD_ASSEMBLER
/* This functionality should really be in the bfd library.  */
static bfd_reloc_code_real_type
reloc (int size, int pcrel, int type)
{
  int length, index;
  bfd_reloc_code_real_type relocs[] =
  {
    BFD_RELOC_NS32K_IMM_8,
    BFD_RELOC_NS32K_IMM_16,
    BFD_RELOC_NS32K_IMM_32,
    BFD_RELOC_NS32K_IMM_8_PCREL,
    BFD_RELOC_NS32K_IMM_16_PCREL,
    BFD_RELOC_NS32K_IMM_32_PCREL,

    /* ns32k displacements.  */
    BFD_RELOC_NS32K_DISP_8,
    BFD_RELOC_NS32K_DISP_16,
    BFD_RELOC_NS32K_DISP_32,
    BFD_RELOC_NS32K_DISP_8_PCREL,
    BFD_RELOC_NS32K_DISP_16_PCREL,
    BFD_RELOC_NS32K_DISP_32_PCREL,

    /* Normal 2's complement.  */
    BFD_RELOC_8,
    BFD_RELOC_16,
    BFD_RELOC_32,
    BFD_RELOC_8_PCREL,
    BFD_RELOC_16_PCREL,
    BFD_RELOC_32_PCREL
  };

  switch (size)
    {
    case 1:
      length = 0;
      break;
    case 2:
      length = 1;
      break;
    case 4:
      length = 2;
      break;
    default:
      length = -1;
      break;
    }

  index = length + 3 * pcrel + 6 * type;

  if (index >= 0 && index < sizeof (relocs) / sizeof (relocs[0]))
    return relocs[index];

  if (pcrel)
    as_bad (_("Can not do %d byte pc-relative relocation for storage type %d"),
	    size, type);
  else
    as_bad (_("Can not do %d byte relocation for storage type %d"),
	    size, type);

  return BFD_RELOC_NONE;

}
#endif

void
md_assemble (line)
     char *line;
{
  freeptr = freeptr_static;
  parse (line, 0);		/* Explode line to more fix form in iif.  */
  convert_iif ();		/* Convert iif to frags, fix's etc.  */
#ifdef SHOW_NUM
  printf (" \t\t\t%s\n", line);
#endif
}

void
md_begin ()
{
  /* Build a hashtable of the instructions.  */
  const struct ns32k_opcode *ptr;
  const char *stat;
  inst_hash_handle = hash_new ();

  for (ptr = ns32k_opcodes; ptr < endop; ptr++)
    {
      if ((stat = hash_insert (inst_hash_handle, ptr->name, (char *) ptr)))
	/* Fatal.  */
	as_fatal (_("Can't hash %s: %s"), ptr->name, stat);
    }

  /* Some private space please!  */
  freeptr_static = (char *) malloc (PRIVATE_SIZE);
}

/* Must be equal to MAX_PRECISON in atof-ieee.c.  */
#define MAX_LITTLENUMS 6

/* Turn the string pointed to by litP into a floating point constant
   of type TYPE, and emit the appropriate bytes.  The number of
   LITTLENUMS emitted is stored in *SIZEP.  An error message is
   returned, or NULL on OK.  */

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)
    {
    case 'f':
      prec = 2;
      break;

    case 'd':
      prec = 4;
      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; prec--;)
    {
      md_number_to_chars (litP, (long) (*--wordP), sizeof (LITTLENUM_TYPE));
      litP += sizeof (LITTLENUM_TYPE);
    }

  return 0;
}

/* Convert number to chars in correct order.  */

void
md_number_to_chars (buf, value, nbytes)
     char *buf;
     valueT value;
     int nbytes;
{
  number_to_chars_littleendian (buf, value, nbytes);
}

/* This is a variant of md_numbers_to_chars. The reason for its'
   existence is the fact that ns32k uses Huffman coded
   displacements. This implies that the bit order is reversed in
   displacements and that they are prefixed with a size-tag.

   binary: msb -> lsb
   0xxxxxxx				byte
   10xxxxxx xxxxxxxx			word
   11xxxxxx xxxxxxxx xxxxxxxx xxxxxxxx	double word

   This must be taken care of and we do it here!  */

static void
md_number_to_disp (buf, val, n)
     char *buf;
     long val;
     char n;
{
  switch (n)
    {
    case 1:
      if (val < -64 || val > 63)
	as_warn (_("Byte displacement out of range.  line number not valid"));
      val &= 0x7f;
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    case 2:
      if (val < -8192 || val > 8191)
	as_warn (_("Word displacement out of range.  line number not valid"));
      val &= 0x3fff;
      val |= 0x8000;
#ifdef SHOW_NUM
      printf ("%x ", val >> 8 & 0xff);
#endif
      *buf++ = (val >> 8);
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    case 4:
      if (val < -0x20000000 || val >= 0x20000000)
	as_warn (_("Double word displacement out of range"));
      val |= 0xc0000000;
#ifdef SHOW_NUM
      printf ("%x ", val >> 24 & 0xff);
#endif
      *buf++ = (val >> 24);
#ifdef SHOW_NUM
      printf ("%x ", val >> 16 & 0xff);
#endif
      *buf++ = (val >> 16);
#ifdef SHOW_NUM
      printf ("%x ", val >> 8 & 0xff);
#endif
      *buf++ = (val >> 8);
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    default:
      as_fatal (_("Internal logic error.  line %s, file \"%s\""),
		__LINE__, __FILE__);
    }
}

static void
md_number_to_imm (buf, val, n)
     char *buf;
     long val;
     char n;
{
  switch (n)
    {
    case 1:
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    case 2:
#ifdef SHOW_NUM
      printf ("%x ", val >> 8 & 0xff);
#endif
      *buf++ = (val >> 8);
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    case 4:
#ifdef SHOW_NUM
      printf ("%x ", val >> 24 & 0xff);
#endif
      *buf++ = (val >> 24);
#ifdef SHOW_NUM
      printf ("%x ", val >> 16 & 0xff);
#endif
      *buf++ = (val >> 16);
#ifdef SHOW_NUM
      printf ("%x ", val >> 8 & 0xff);
#endif
      *buf++ = (val >> 8);
#ifdef SHOW_NUM
      printf ("%x ", val & 0xff);
#endif
      *buf++ = val;
      break;
    default:
      as_fatal (_("Internal logic error. line %s, file \"%s\""),