c4x.c

gcc-you can use this code to learn something about gcc, and inquire further into linux,

	  fprintf (file, "%s\t@", TARGET_C3X ? "ldp" : "ldpk");
          output_address (XEXP (op, 0));
	  fprintf (file, "\n\t");
	}
      return;

    case 'O':			/* Offset address.  */
      if (code == MEM && c4x_autoinc_operand (op, Pmode))
	break;
      else if (code == MEM)
	output_address (XEXP (adjust_address (op, VOIDmode, 1), 0));
      else if (code == REG)
	fprintf (file, "%s", reg_names[REGNO (op) + 1]);
      else
	fatal_insn ("c4x_print_operand: %%O inconsistency", op);
      return;

    case 'C':			/* Call.  */
      break;

    case 'U':			/* Call/callu.  */
      if (code != SYMBOL_REF)
	fprintf (file, "u");
      return;

    default:
      break;
    }
  
  switch (code)
    {
    case REG:
      if (GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT
	  && ! TARGET_TI)
	fprintf (file, "%s", float_reg_names[REGNO (op)]);
      else
	fprintf (file, "%s", reg_names[REGNO (op)]);
      break;
      
    case MEM:
      output_address (XEXP (op, 0));
      break;
      
    case CONST_DOUBLE:
      {
	char str[64];
	
	real_to_decimal (str, CONST_DOUBLE_REAL_VALUE (op),
			 sizeof (str), 0, 1);
	fprintf (file, "%s", str);
      }
      break;
      
    case CONST_INT:
      fprintf (file, "%d", INTVAL (op));
      break;
      
    case NE:
      fprintf (file, "ne");
      break;
      
    case EQ:
      fprintf (file, "eq");
      break;
      
    case GE:
      fprintf (file, "ge");
      break;

    case GT:
      fprintf (file, "gt");
      break;

    case LE:
      fprintf (file, "le");
      break;

    case LT:
      fprintf (file, "lt");
      break;

    case GEU:
      fprintf (file, "hs");
      break;

    case GTU:
      fprintf (file, "hi");
      break;

    case LEU:
      fprintf (file, "ls");
      break;

    case LTU:
      fprintf (file, "lo");
      break;

    case SYMBOL_REF:
      output_addr_const (file, op);
      break;

    case CONST:
      output_addr_const (file, XEXP (op, 0));
      break;

    case CODE_LABEL:
      break;

    default:
      fatal_insn ("c4x_print_operand: Bad operand case", op);
      break;
    }
}


void
c4x_print_operand_address (file, addr)
     FILE *file;
     rtx addr;
{
  switch (GET_CODE (addr))
    {
    case REG:
      fprintf (file, "*%s", reg_names[REGNO (addr)]);
      break;

    case PRE_DEC:
      fprintf (file, "*--%s", reg_names[REGNO (XEXP (addr, 0))]);
      break;

    case POST_INC:
      fprintf (file, "*%s++", reg_names[REGNO (XEXP (addr, 0))]);
      break;

    case POST_MODIFY:
      {
	rtx op0 = XEXP (XEXP (addr, 1), 0);
	rtx op1 = XEXP (XEXP (addr, 1), 1);
	
	if (GET_CODE (XEXP (addr, 1)) == PLUS && REG_P (op1))
	  fprintf (file, "*%s++(%s)", reg_names[REGNO (op0)],
		   reg_names[REGNO (op1)]);
	else if (GET_CODE (XEXP (addr, 1)) == PLUS && INTVAL (op1) > 0)
	  fprintf (file, "*%s++(%d)", reg_names[REGNO (op0)],
		   INTVAL (op1));
	else if (GET_CODE (XEXP (addr, 1)) == PLUS && INTVAL (op1) < 0)
	  fprintf (file, "*%s--(%d)", reg_names[REGNO (op0)],
		   -INTVAL (op1));
	else if (GET_CODE (XEXP (addr, 1)) == MINUS && REG_P (op1))
	  fprintf (file, "*%s--(%s)", reg_names[REGNO (op0)],
		   reg_names[REGNO (op1)]);
	else
	  fatal_insn ("c4x_print_operand_address: Bad post_modify", addr);
      }
      break;
      
    case PRE_MODIFY:
      {
	rtx op0 = XEXP (XEXP (addr, 1), 0);
	rtx op1 = XEXP (XEXP (addr, 1), 1);
	
	if (GET_CODE (XEXP (addr, 1)) == PLUS && REG_P (op1))
	  fprintf (file, "*++%s(%s)", reg_names[REGNO (op0)],
		   reg_names[REGNO (op1)]);
	else if (GET_CODE (XEXP (addr, 1)) == PLUS && INTVAL (op1) > 0)
	  fprintf (file, "*++%s(%d)", reg_names[REGNO (op0)],
		   INTVAL (op1));
	else if (GET_CODE (XEXP (addr, 1)) == PLUS && INTVAL (op1) < 0)
	  fprintf (file, "*--%s(%d)", reg_names[REGNO (op0)],
		   -INTVAL (op1));
	else if (GET_CODE (XEXP (addr, 1)) == MINUS && REG_P (op1))
	  fprintf (file, "*--%s(%s)", reg_names[REGNO (op0)],
		   reg_names[REGNO (op1)]);
	else
	  fatal_insn ("c4x_print_operand_address: Bad pre_modify", addr);
      }
      break;
      
    case PRE_INC:
      fprintf (file, "*++%s", reg_names[REGNO (XEXP (addr, 0))]);
      break;

    case POST_DEC:
      fprintf (file, "*%s--", reg_names[REGNO (XEXP (addr, 0))]);
      break;

    case PLUS:			/* Indirect with displacement.  */
      {
	rtx op0 = XEXP (addr, 0);
	rtx op1 = XEXP (addr, 1);

	if (REG_P (op0))
	  {
	    if (REG_P (op1))
	      {
		if (IS_INDEX_REG (op0))
		  {
		    fprintf (file, "*+%s(%s)",
			     reg_names[REGNO (op1)],
			     reg_names[REGNO (op0)]);	/* Index + base.  */
		  }
		else
		  {
		    fprintf (file, "*+%s(%s)",
			     reg_names[REGNO (op0)],
			     reg_names[REGNO (op1)]);	/* Base + index.  */
		  }
	      }
	    else if (INTVAL (op1) < 0)
	      {
		fprintf (file, "*-%s(%d)",
			 reg_names[REGNO (op0)],
			 -INTVAL (op1));	/* Base - displacement.  */
	      }
	    else
	      {
		fprintf (file, "*+%s(%d)",
			 reg_names[REGNO (op0)],
			 INTVAL (op1));	/* Base + displacement.  */
	      }
	  }
	else
          fatal_insn ("c4x_print_operand_address: Bad operand case", addr);
      }
      break;

    case LO_SUM:
      {
	rtx op0 = XEXP (addr, 0);
	rtx op1 = XEXP (addr, 1);
	  
	if (REG_P (op0) && REGNO (op0) == DP_REGNO)
	  c4x_print_operand_address (file, op1);
	else
          fatal_insn ("c4x_print_operand_address: Bad operand case", addr);
      }
      break;

    case CONST:
    case SYMBOL_REF:
    case LABEL_REF:
      fprintf (file, "@");
      output_addr_const (file, addr);
      break;

      /* We shouldn't access CONST_INT addresses.  */
    case CONST_INT:

    default:
      fatal_insn ("c4x_print_operand_address: Bad operand case", addr);
      break;
    }
}


/* Return nonzero if the floating point operand will fit
   in the immediate field.  */

static int
c4x_immed_float_p (op)
     rtx op;
{
  long convval[2];
  int exponent;
  REAL_VALUE_TYPE r;

  REAL_VALUE_FROM_CONST_DOUBLE (r, op);
  if (GET_MODE (op) == HFmode)
    REAL_VALUE_TO_TARGET_DOUBLE (r, convval);
  else
    {
      REAL_VALUE_TO_TARGET_SINGLE (r, convval[0]);
      convval[1] = 0;
    }

  /* Sign extend exponent.  */
  exponent = (((convval[0] >> 24) & 0xff) ^ 0x80) - 0x80;
  if (exponent == -128)
    return 1;			/* 0.0  */
  if ((convval[0] & 0x00000fff) != 0 || convval[1] != 0)
    return 0;			/* Precision doesn't fit.  */
  return (exponent <= 7)	/* Positive exp.  */
    && (exponent >= -7);	/* Negative exp.  */
}


/* The last instruction in a repeat block cannot be a Bcond, DBcound,
   CALL, CALLCond, TRAPcond, RETIcond, RETScond, IDLE, RPTB or RPTS.

   None of the last four instructions from the bottom of the block can
   be a BcondD, BRD, DBcondD, RPTBD, LAJ, LAJcond, LATcond, BcondAF,
   BcondAT or RETIcondD.

   This routine scans the four previous insns for a jump insn, and if
   one is found, returns 1 so that we bung in a nop instruction.
   This simple minded strategy will add a nop, when it may not
   be required.  Say when there is a JUMP_INSN near the end of the
   block that doesn't get converted into a delayed branch.

   Note that we cannot have a call insn, since we don't generate
   repeat loops with calls in them (although I suppose we could, but
   there's no benefit.)  

   !!! FIXME.  The rptb_top insn may be sucked into a SEQUENCE.  */

int
c4x_rptb_nop_p (insn)
     rtx insn;
{
  rtx start_label;
  int i;

  /* Extract the start label from the jump pattern (rptb_end).  */
  start_label = XEXP (XEXP (SET_SRC (XVECEXP (PATTERN (insn), 0, 0)), 1), 0);

  /* If there is a label at the end of the loop we must insert
     a NOP.  */
  do {
    insn = previous_insn (insn);
  } while (GET_CODE (insn) == NOTE
	   || GET_CODE (insn) == USE
	   || GET_CODE (insn) == CLOBBER);
  if (GET_CODE (insn) == CODE_LABEL)
    return 1;

  for (i = 0; i < 4; i++)
    {
      /* Search back for prev non-note and non-label insn.  */
      while (GET_CODE (insn) == NOTE || GET_CODE (insn) == CODE_LABEL
	     || GET_CODE (insn) == USE || GET_CODE (insn) == CLOBBER)
	{
	  if (insn == start_label)
	    return i == 0;

	  insn = previous_insn (insn);
	};

      /* If we have a jump instruction we should insert a NOP. If we
	 hit repeat block top we should only insert a NOP if the loop
	 is empty.  */
      if (GET_CODE (insn) == JUMP_INSN)
	return 1;
      insn = previous_insn (insn);
    }
  return 0;
}


/* The C4x looping instruction needs to be emitted at the top of the
  loop.  Emitting the true RTL for a looping instruction at the top of
  the loop can cause problems with flow analysis.  So instead, a dummy
  doloop insn is emitted at the end of the loop.  This routine checks
  for the presence of this doloop insn and then searches back to the
  top of the loop, where it inserts the true looping insn (provided
  there are no instructions in the loop which would cause problems).
  Any additional labels can be emitted at this point.  In addition, if
  the desired loop count register was not allocated, this routine does
  nothing. 

  Before we can create a repeat block looping instruction we have to
  verify that there are no jumps outside the loop and no jumps outside
  the loop go into this loop. This can happen in the basic blocks reorder
  pass. The C4x cpu can not handle this.  */

static int
c4x_label_ref_used_p (x, code_label)
     rtx x, code_label;
{
  enum rtx_code code;
  int i, j;
  const char *fmt;

  if (x == 0)
    return 0;

  code = GET_CODE (x);
  if (code == LABEL_REF)
    return INSN_UID (XEXP (x,0)) == INSN_UID (code_label);

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	{
          if (c4x_label_ref_used_p (XEXP (x, i), code_label))
	    return 1;
	}
      else if (fmt[i] == 'E')
        for (j = XVECLEN (x, i) - 1; j >= 0; j--)
          if (c4x_label_ref_used_p (XVECEXP (x, i, j), code_label))
	    return 1;
    }
  return 0;
}


static int
c4x_rptb_valid_p (insn, start_label)
     rtx insn, start_label;
{
  rtx end = insn;
  rtx start;
  rtx tmp;

  /* Find the start label.  */
  for (; insn; insn = PREV_INSN (insn))
    if (insn == start_label)
      break;

  /* Note found then we can not use a rptb or rpts.  The label was
     probably moved by the basic block reorder pass.  */
  if (! insn)
    return 0;

  start = insn;
  /* If any jump jumps inside this block then we must fail.  */
  for (insn = PREV_INSN (start); insn; insn = PREV_INSN (insn))
    {
      if (GET_CODE (insn) == CODE_LABEL)
	{
	  for (tmp = NEXT_INSN (start); tmp != end; tmp = NEXT_INSN(tmp))
	    if (GET_CODE (tmp) == JUMP_INSN
                && c4x_label_ref_used_p (tmp, insn))
	      return 0;
        }
    }
  for (insn = NEXT_INSN (end); insn; insn = NEXT_INSN (insn))
    {
      if (GET_CODE (insn) == CODE_LABEL)
	{
	  for (tmp = NEXT_INSN (start); tmp != end; tmp = NEXT_INSN(tmp))
	    if (GET_CODE (tmp) == JUMP_INSN
                && c4x_label_ref_used_p (tmp, insn))
	      return 0;
        }
    }
  /* If any jump jumps outside this block then we must fail.  */
  for (insn = NEXT_INSN (start); insn != end; insn = NEXT_INSN (insn))
    {
      if (GET_CODE (insn) == CODE_LABEL)
	{
	  for (tmp = NEXT_INSN (end); tmp; tmp = NEXT_INSN(tmp))
	    if (GET_CODE (tmp) == JUMP_INSN
                && c4x_label_ref_used_p (tmp, insn))
	      return 0;
	  for (tmp = PREV_INSN (start); tmp; tmp = PREV_INSN(tmp))
	    if (GET_CODE (tmp) == JUMP_INSN
                && c4x_label_ref_used_p (tmp, insn))
	      return 0;
        }
    }

  /* All checks OK.  */
  return 1;
}


void
c4x_rptb_insert (insn)
     rtx insn;
{
  rtx end_label;
  rtx start_label;
  rtx new_start_label;
  rtx count_reg;

  /* If the count register has not been allocated to RC, say if
     there is a movstr pattern in the loop, then do not insert a
     RPTB instruction.  Instead we emit a decrement and branch
     at the end of the loop.  */
  count_reg = XEXP (XEXP (SET_SRC (XVECEXP (PATTERN (insn), 0, 0)), 0), 0);
  if (REGNO (count_reg) != RC_REGNO)
    return;