tc-cris.c

基于4个mips核的noc设计

	  *size_bitsp = 0;
	  break;

	case 'W':
	case 'w':
	  *size_bitsp = 1;
	  break;

	case 'D':
	case 'd':
	  *size_bitsp = 2;
	  break;

	default:
	  return 0;
	}

      /* Consume the size letter.  */
      (*cPP)++;
      return 1;
    }
}

/* Get a B or W size modifier from the string pointed out by *cPP,
   which must point to a '.' in front of the modifier.	On successful
   return, *cPP is advanced to the character following the size
   modifier, and is undefined otherwise.

   cPP		Pointer to pointer to string starting
		with the size modifier.

   size_bitsp	Pointer to variable to contain the size bits on
		successful return.

   Return 1 iff a correct size modifier is found, else 0.  */

static int
get_bw_size_modifier (cPP, size_bitsp)
     char **cPP;
     int *size_bitsp;
{
  if (**cPP != '.')
    return 0;
  else
    {
      /* Consume the '.'.  */
      (*cPP)++;

      switch (**cPP)
	{
	case 'B':
	case 'b':
	  *size_bitsp = 0;
	  break;

	case 'W':
	case 'w':
	  *size_bitsp = 1;
	  break;

	default:
	  return 0;
	}

      /* Consume the size letter.  */
      (*cPP)++;
      return 1;
    }
}

/* Get a general register from the string pointed out by *cPP.  The
   variable *cPP is advanced to the character following the general
   register name on a successful return, and has its initial position
   otherwise.

   cPP	    Pointer to pointer to string, beginning with a general
	    register name.

   regnop   Pointer to int containing the register number.

   Return 1 iff a correct general register designator is found,
	    else 0.  */

static int
get_gen_reg (cPP, regnop)
     char **cPP;
     int *regnop;
{
  char *oldp;
  oldp = *cPP;

  /* Handle a sometimes-mandatory dollar sign as register prefix.  */
  if (**cPP == REGISTER_PREFIX_CHAR)
    (*cPP)++;
  else if (demand_register_prefix)
    return 0;

  switch (**cPP)
    {
    case 'P':
    case 'p':
      /* "P" as in "PC"?  Consume the "P".  */
      (*cPP)++;

      if ((**cPP == 'C' || **cPP == 'c')
	  && ! isalnum ((*cPP)[1]))
	{
	  /* It's "PC": consume the "c" and we're done.  */
	  (*cPP)++;
	  *regnop = REG_PC;
	  return 1;
	}
      break;

    case 'R':
    case 'r':
      /* Hopefully r[0-9] or r1[0-5].  Consume 'R' or 'r'.  */
      (*cPP)++;

      if (isdigit (**cPP))
	{
	  /* It's r[0-9].  Consume and check the next digit.  */
	  *regnop = **cPP - '0';
	  (*cPP)++;

	  if (! isalnum (**cPP))
	    {
	      /* No more digits, we're done.  */
	      return 1;
	    }
	  else
	    {
	      /* One more digit.  Consume and add.  */
	      *regnop = *regnop * 10 + (**cPP - '0');

	      /* We need to check for a valid register number; Rn,
		 0 <= n <= MAX_REG.  */
	      if (*regnop <= MAX_REG)
		{
		  /* Consume second digit.  */
		  (*cPP)++;
		  return 1;
		}
	    }
	}
      break;

    case 'S':
    case 's':
      /* "S" as in "SP"?  Consume the "S".  */
      (*cPP)++;
      if (**cPP == 'P' || **cPP == 'p')
	{
	  /* It's "SP": consume the "p" and we're done.  */
	  (*cPP)++;
	  *regnop = REG_SP;
	  return 1;
	}
      break;

    default:
      /* Just here to silence compilation warnings.  */
      ;
    }

  /* We get here if we fail.  Restore the pointer.  */
  *cPP = oldp;
  return 0;
}

/* Get a special register from the string pointed out by *cPP. The
   variable *cPP is advanced to the character following the special
   register name if one is found, and retains its original position
   otherwise.

   cPP	    Pointer to pointer to string starting with a special register
	    name.

   sregpp   Pointer to Pointer to struct spec_reg, where a pointer to the
	    register description will be stored.

   Return 1 iff a correct special register name is found.  */

static int
get_spec_reg (cPP, sregpp)
     char **cPP;
     const struct cris_spec_reg **sregpp;
{
  char *s1;
  const char *s2;
  char *name_begin = *cPP;

  const struct cris_spec_reg *sregp;

  /* Handle a sometimes-mandatory dollar sign as register prefix.  */
  if (*name_begin == REGISTER_PREFIX_CHAR)
    name_begin++;
  else if (demand_register_prefix)
    return 0;

  /* Loop over all special registers.  */
  for (sregp = cris_spec_regs; sregp->name != NULL; sregp++)
    {
      /* Start over from beginning of the supposed name.  */
      s1 = name_begin;
      s2 = sregp->name;

      while (*s2 != '\0'
	     && (isupper (*s1) ? tolower (*s1) == *s2 : *s1 == *s2))
	{
	  s1++;
	  s2++;
	}

      /* For a match, we must have consumed the name in the table, and we
	 must be outside what could be part of a name.	Assume here that a
	 test for alphanumerics is sufficient for a name test.  */
      if (*s2 == 0 && ! isalnum (*s1))
	{
	  /* We have a match.  Update the pointer and be done.  */
	  *cPP = s1;
	  *sregpp = sregp;
	  return 1;
	}
    }

  /* If we got here, we did not find any name.  */
  return 0;
}

/* Get an unprefixed or side-effect-prefix operand from the string pointed
   out by *cPP.  The pointer *cPP is advanced to the character following
   the indirect operand if we have success, else it contains an undefined
   value.

   cPP		 Pointer to pointer to string beginning with the first
		 character of the supposed operand.

   prefixp	 Pointer to structure containing an optional instruction
		 prefix.

   is_autoincp	 Pointer to int indicating the indirect or autoincrement
		 bits.

   src_regnop	 Pointer to int containing the source register number in
		 the instruction.

   imm_foundp	 Pointer to an int indicating if an immediate expression
		 is found.

   imm_exprP	 Pointer to a structure containing an immediate
		 expression, if success and if *imm_foundp is nonzero.

   Return 1 iff a correct indirect operand is found.  */

static int
get_autoinc_prefix_or_indir_op (cPP, prefixp, is_autoincp, src_regnop,
				imm_foundp, imm_exprP)
     char **cPP;
     struct cris_prefix *prefixp;
     int *is_autoincp;
     int *src_regnop;
     int *imm_foundp;
     expressionS *imm_exprP;
{
  /* Assume there was no immediate mode expression.  */
  *imm_foundp = 0;

  if (**cPP == '[')
    {
      /* So this operand is one of:
	 Indirect: [rN]
	 Autoincrement: [rN+]
	 Indexed with assign: [rN=rM+rO.S]
	 Offset with assign: [rN=rM+I], [rN=rM+[rO].s], [rN=rM+[rO+].s]

	 Either way, consume the '['.  */
      (*cPP)++;

      /* Get the rN register.  */
      if (! get_gen_reg (cPP, src_regnop))
	/* If there was no register, then this cannot match.  */
	return 0;
      else
	{
	  /* We got the register, now check the next character.  */
	  switch (**cPP)
	    {
	    case ']':
	      /* Indirect mode.  We're done here.  */
	      prefixp->kind = PREFIX_NONE;
	      *is_autoincp = 0;
	      break;

	    case '+':
	      /* This must be an auto-increment mode, if there's a
		 match.  */
	      prefixp->kind = PREFIX_NONE;
	      *is_autoincp = 1;

	      /* We consume this character and break out to check the
		 closing ']'.  */
	      (*cPP)++;
	      break;

	    case '=':
	      /* This must be indexed with assign, or offset with assign
		 to match.  */
	      (*cPP)++;

	      /* Either way, the next thing must be a register.  */
	      if (! get_gen_reg (cPP, &prefixp->base_reg_number))
		/* No register, no match.  */
		return 0;
	      else
		{
		  /* We've consumed "[rN=rM", so we must be looking at
		     "+rO.s]" or "+I]", or "-I]", or "+[rO].s]" or
		     "+[rO+].s]".  */
		  if (**cPP == '+')
		    {
		      int index_reg_number;
		      (*cPP)++;

		      if (**cPP == '[')
			{
			  int size_bits;
			  /* This must be [rx=ry+[rz].s] or
			     [rx=ry+[rz+].s] or no match.  We must be
			     looking at rz after consuming the '['.  */
			  (*cPP)++;

			  if (!get_gen_reg (cPP, &index_reg_number))
			    return 0;

			  prefixp->kind = PREFIX_BDAP;
			  prefixp->opcode
			    = (BDAP_INDIR_OPCODE
			       + (prefixp->base_reg_number << 12)
			       + index_reg_number);

			  if (**cPP == '+')
			    {
			      /* We've seen "[rx=ry+[rz+" here, so now we
				 know that there must be "].s]" left to
				 check.  */
			      (*cPP)++;
			      prefixp->opcode |= AUTOINCR_BIT << 8;
			    }

			  /* If it wasn't autoincrement, we don't need to
			     add anything.  */

			  /* Check the next-to-last ']'.  */
			  if (**cPP != ']')
			    return 0;

			  (*cPP)++;

			  /* Check the ".s" modifier.  */
			  if (! get_bwd_size_modifier (cPP, &size_bits))
			    return 0;

			  prefixp->opcode |= size_bits << 4;

			  /* Now we got [rx=ry+[rz+].s or [rx=ry+[rz].s.
			     We break out to check the final ']'.  */
			  break;
			}
		      /* It wasn't an indirection.  Check if it's a
			 register.  */
		      else if (get_gen_reg (cPP, &index_reg_number))
			{
			  int size_bits;

			  /* Indexed with assign mode: "[rN+rM.S]".  */
			  prefixp->kind = PREFIX_BIAP;
			  prefixp->opcode
			    = (BIAP_OPCODE + (index_reg_number << 12)
			       + prefixp->base_reg_number /* << 0 */);

			  if (! get_bwd_size_modifier (cPP, &size_bits))
			    /* Size missing, this isn't a match.  */
			    return 0;
			  else
			    {
			      /* Size found, break out to check the
				 final ']'.  */
			      prefixp->opcode |= size_bits << 4;
			      break;
			    }
			}
		      /* Not a register.  Then this must be "[rN+I]".  */
		      else if (cris_get_expression (cPP, &prefixp->expr))
			{
			  /* We've got offset with assign mode.  Fill
			     in the blanks and break out to match the
			     final ']'.  */
			  prefixp->kind = PREFIX_BDAP_IMM;
			  break;
			}
		      else
			/* Neither register nor expression found, so
			   this can't be a match.  */
			return 0;
		    }
		  /* Not "[rN+" but perhaps "[rN-"?  */
		  else if (**cPP == '-')
		    {
		      /* We must have an offset with assign mode.  */
		      if (! cris_get_expression (cPP, &prefixp->expr))
			/* No expression, no match.  */
			return 0;
		      else
			{
			  /* We've got offset with assign mode.  Fill
			     in the blanks and break out to match the
			     final ']'.  */
			  prefixp->kind = PREFIX_BDAP_IMM;
			  break;
			}
		    }
		  else
		    /* Neither '+' nor '-' after "[rN=rM".  Lose.  */
		    return 0;
		}
	    default:
	      /* Neither ']' nor '+' nor '=' after "[rN".  Lose.  */
	      return 0;
	    }
	}

      /* When we get here, we have a match and will just check the closing
	 ']'.  We can still fail though.  */
      if (**cPP != ']')
	return 0;
      else
	{
	  /* Don't forget to consume the final ']'.
	     Then return in glory.  */
	  (*cPP)++;
	  return 1;
	}
    }
  /* No indirection.  Perhaps a constant?  */
  else if (cris_get_expression (cPP, imm_exprP))
    {
      /* Expression found, this is immediate mode.  */
      prefixp->kind = PREFIX_NONE;
      *is_autoincp = 1;
      *src_regnop = REG_PC;
      *imm_foundp = 1;
      return 1;
    }

  /* No luck today.  */
  return 0;
}

/* This function gets an indirect operand in a three-address operand
   combination from the string pointed out by *cPP.  The pointer *cPP is
   advanced to the character following the indirect operand on success, or
   has an unspecified value on failure.

   cPP	     Pointer to pointer to string begining
	     with the operand

   prefixp   Pointer to structure containing an
	     instruction prefix

   Returns 1 iff a correct indirect operand is found.  */

static int
get_3op_or_dip_prefix_op (cPP, prefixp)
     char **cPP;
     struct cris_prefix *prefixp;
{
  int reg_number;

  if (**cPP != '[')