cris.c

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

      putc (INTVAL (x) >= -128 && INTVAL (x) <= 255 ? 'b' : 'w', file);
      return;

    case '#':
      /* Output a 'nop' if there's nothing for the delay slot.
	 This method stolen from the sparc files.  */
      if (dbr_sequence_length () == 0)
	fputs ("\n\tnop", file);
      return;

    case 'H':
      /* Print high (most significant) part of something.  */
      switch (GET_CODE (operand))
	{
	case CONST_INT:
	  if (HOST_BITS_PER_WIDE_INT == 32)
	    /* Sign-extension from a normal int to a long long.  */
	    fprintf (file, INTVAL (operand) < 0 ? "-1" : "0");
	  else
	    fprintf (file, "0x%x", (unsigned int)(INTVAL (x) >> 31 >> 1));
	  return;

	case CONST_DOUBLE:
	  /* High part of a long long constant.  */
	  if (GET_MODE (operand) == VOIDmode)
	    {
	      fprintf (file, "0x%x", CONST_DOUBLE_HIGH (x));
	      return;
	    }
	  else
	    LOSE_AND_RETURN ("invalid operand for 'H' modifier", x);

	case REG:
	  /* Print reg + 1.  Check that there's not an attempt to print
	     high-parts of registers like stack-pointer or higher.  */
	  if (REGNO (operand) > STACK_POINTER_REGNUM - 2)
	    LOSE_AND_RETURN ("bad register", operand);
	  fprintf (file, "$%s", reg_names[REGNO (operand) + 1]);
	  return;

	case MEM:
	  /* Adjust memory address to high part.  */
	  {
	    rtx adj_mem = operand;
	    int size
	      = GET_MODE_BITSIZE (GET_MODE (operand)) / BITS_PER_UNIT;

	    /* Adjust so we can use two SImode in DImode.
	       Calling adj_offsettable_operand will make sure it is an
	       offsettable address.  Don't do this for a postincrement
	       though; it should remain as it was.  */
	    if (GET_CODE (XEXP (adj_mem, 0)) != POST_INC)
	      adj_mem
		= adjust_address (adj_mem, GET_MODE (adj_mem), size / 2);

	    output_address (XEXP (adj_mem, 0));
	    return;
	  }

	default:
	  LOSE_AND_RETURN ("invalid operand for 'H' modifier", x);
	}

    case 'L':
      /* Strip the MEM expression.  */
      operand = XEXP (operand, 0);
      break;

    case 'e':
      /* Print 's' if operand is SIGN_EXTEND or 'u' if ZERO_EXTEND unless
	 cris_output_insn_is_bound is nonzero.  */
      if (GET_CODE (operand) != SIGN_EXTEND
	  && GET_CODE (operand) != ZERO_EXTEND
	  && GET_CODE (operand) != CONST_INT)
	LOSE_AND_RETURN ("invalid operand for 'e' modifier", x);

      if (cris_output_insn_is_bound)
	{
	  cris_output_insn_is_bound = 0;
	  return;
	}

      putc (GET_CODE (operand) == SIGN_EXTEND
	    || (GET_CODE (operand) == CONST_INT && INTVAL (operand) < 0)
	    ? 's' : 'u', file);
      return;

    case 'm':
      /* Print the size letter of the inner element.  We can do it by
	 calling ourselves with the 's' modifier.  */
      if (GET_CODE (operand) != SIGN_EXTEND && GET_CODE (operand) != ZERO_EXTEND)
	LOSE_AND_RETURN ("invalid operand for 'm' modifier", x);
      cris_print_operand (file, XEXP (operand, 0), 's');
      return;

    case 'M':
      /* Print the least significant part of operand.  */
      if (GET_CODE (operand) == CONST_DOUBLE)
	{
	  fprintf (file, "0x%x", CONST_DOUBLE_LOW (x));
	  return;
	}
      else if (HOST_BITS_PER_WIDE_INT > 32 && GET_CODE (operand) == CONST_INT)
	{
	  fprintf (file, "0x%x",
		   INTVAL (x) & ((unsigned int) 0x7fffffff * 2 + 1));
	  return;
	}
      /* Otherwise the least significant part equals the normal part,
	 so handle it normally.  */
      break;

    case 'A':
      /* When emitting an add for the high part of a DImode constant, we
	 want to use addq for 0 and adds.w for -1.  */
      if (GET_CODE (operand) != CONST_INT)
	LOSE_AND_RETURN ("invalid operand for 'A' modifier", x);
      fprintf (file, INTVAL (operand) < 0 ? "adds.w" : "addq");
      return;

    case 'D':
      /* When emitting an sub for the high part of a DImode constant, we
	 want to use subq for 0 and subs.w for -1.  */
      if (GET_CODE (operand) != CONST_INT)
	LOSE_AND_RETURN ("invalid operand for 'D' modifier", x);
      fprintf (file, INTVAL (operand) < 0 ? "subs.w" : "subq");
      return;

    case 'S':
      /* Print the operand as the index-part of an address.
	 Easiest way out is to use cris_print_index.  */
      cris_print_index (operand, file);
      return;

    case 'T':
      /* Print the size letter for an operand to a MULT, which must be a
	 const_int with a suitable value.  */
      if (GET_CODE (operand) != CONST_INT || INTVAL (operand) > 4)
	LOSE_AND_RETURN ("invalid operand for 'T' modifier", x);
      fprintf (file, "%s", mults[INTVAL (operand)]);
      return;

    case 0:
      /* No code, print as usual.  */
      break;

    default:
      LOSE_AND_RETURN ("invalid operand modifier letter", x);
    }

  /* Print an operand as without a modifier letter.  */
  switch (GET_CODE (operand))
    {
    case REG:
      if (REGNO (operand) > 15)
	internal_error ("internal error: bad register: %d", REGNO (operand));
      fprintf (file, "$%s", reg_names[REGNO (operand)]);
      return;

    case MEM:
      output_address (XEXP (operand, 0));
      return;

    case CONST_DOUBLE:
      if (GET_MODE (operand) == VOIDmode)
	/* A long long constant.  */
	output_addr_const (file, operand);
      else
	{
	  /* Only single precision is allowed as plain operands the
	     moment.  FIXME:  REAL_VALUE_FROM_CONST_DOUBLE isn't
	     documented.  */
	  REAL_VALUE_TYPE r;
	  long l;

	  /* FIXME:  Perhaps check overflow of the "single".  */
	  REAL_VALUE_FROM_CONST_DOUBLE (r, operand);
	  REAL_VALUE_TO_TARGET_SINGLE (r, l);

	  fprintf (file, "0x%lx", l);
	}
      return;

    case UNSPEC:
      ASSERT_PLT_UNSPEC (operand);
      /* Fall through.  */

    case CONST:
      cris_output_addr_const (file, operand);
      return;

    case MULT:
    case ASHIFT:
      {
	/* For a (MULT (reg X) const_int) we output "rX.S".  */
	int i = GET_CODE (XEXP (operand, 1)) == CONST_INT
	  ? INTVAL (XEXP (operand, 1)) : INTVAL (XEXP (operand, 0));
	rtx reg = GET_CODE (XEXP (operand, 1)) == CONST_INT
	  ? XEXP (operand, 0) : XEXP (operand, 1);

	if (GET_CODE (reg) != REG
	    || (GET_CODE (XEXP (operand, 0)) != CONST_INT
		&& GET_CODE (XEXP (operand, 1)) != CONST_INT))
	  LOSE_AND_RETURN ("unexpected multiplicative operand", x);

	cris_print_base (reg, file);
	fprintf (file, ".%c",
		 i == 0 || (i == 1 && GET_CODE (operand) == MULT) ? 'b'
		 : i == 4 ? 'd'
		 : (i == 2 && GET_CODE (operand) == MULT) || i == 1 ? 'w'
		 : 'd');
	return;
      }

    default:
      /* No need to handle all strange variants, let output_addr_const
	 do it for us.  */
      if (CONSTANT_P (operand))
	{
	  cris_output_addr_const (file, operand);
	  return;
	}

      LOSE_AND_RETURN ("unexpected operand", x);
    }
}

/* The PRINT_OPERAND_ADDRESS worker.  */

void
cris_print_operand_address (file, x)
     FILE *file;
     rtx x;
{
  /* All these were inside MEM:s so output indirection characters.  */
  putc ('[', file);

  if (CONSTANT_ADDRESS_P (x))
    cris_output_addr_const (file, x);
  else if (BASE_OR_AUTOINCR_P (x))
    cris_print_base (x, file);
  else if (GET_CODE (x) == PLUS)
    {
      rtx x1, x2;

      x1 = XEXP (x, 0);
      x2 = XEXP (x, 1);
      if (BASE_P (x1))
	{
	  cris_print_base (x1, file);
	  cris_print_index (x2, file);
	}
      else if (BASE_P (x2))
	{
	  cris_print_base (x2, file);
	  cris_print_index (x1, file);
	}
      else
	LOSE_AND_RETURN ("unrecognized address", x);
    }
  else if (GET_CODE (x) == MEM)
    {
      /* A DIP.  Output more indirection characters.  */
      putc ('[', file);
      cris_print_base (XEXP (x, 0), file);
      putc (']', file);
    }
  else
    LOSE_AND_RETURN ("unrecognized address", x);

  putc (']', file);
}

/* The RETURN_ADDR_RTX worker.
   We mark that the return address is used, either by EH or
   __builtin_return_address, for use by the function prologue and
   epilogue.  FIXME: This isn't optimal; we just use the mark in the
   prologue and epilogue to say that the return address is to be stored
   in the stack frame.  We could return SRP for leaf-functions and use the
   initial-value machinery.  */

rtx
cris_return_addr_rtx (count, frameaddr)
     int count;
     rtx frameaddr ATTRIBUTE_UNUSED;
{
  cfun->machine->needs_return_address_on_stack = 1;

  /* The return-address is stored just above the saved frame-pointer (if
     present).  Apparently we can't eliminate from the frame-pointer in
     that direction, so use the incoming args (maybe pretended) pointer.  */
  return count == 0
    ? gen_rtx_MEM (Pmode, plus_constant (virtual_incoming_args_rtx, -4))
    : NULL_RTX;
}

/* This used to be the INITIAL_FRAME_POINTER_OFFSET worker; now only
   handles FP -> SP elimination offset.  */

static int
cris_initial_frame_pointer_offset ()
{
  int regno;

  /* Initial offset is 0 if we don't have a frame pointer.  */
  int offs = 0;

  /* And 4 for each register pushed.  */
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if ((((regs_ever_live[regno]
	   && !call_used_regs[regno])
	  || (regno == (int) PIC_OFFSET_TABLE_REGNUM
	      && (current_function_uses_pic_offset_table
		  /* It is saved anyway, if there would be a gap.  */
		  || (flag_pic
		      && regs_ever_live[regno + 1]
		      && !call_used_regs[regno + 1]))))
	 && (regno != FRAME_POINTER_REGNUM || !frame_pointer_needed)
	 && regno != CRIS_SRP_REGNUM)
	|| (current_function_calls_eh_return
	    && (regno == EH_RETURN_DATA_REGNO (0)
		|| regno == EH_RETURN_DATA_REGNO (1)
		|| regno == EH_RETURN_DATA_REGNO (2)
		|| regno == EH_RETURN_DATA_REGNO (3))))
      offs += 4;

  /* And then, last, we add the locals allocated.  */
  offs += get_frame_size ();

  /* And more; the accumulated args size.  */
  offs += current_function_outgoing_args_size;

  /* Then round it off, in case we use aligned stack.  */
  if (TARGET_STACK_ALIGN)
    offs = TARGET_ALIGN_BY_32 ? (offs + 3) & ~3 : (offs + 1) & ~1;

  return offs;
}

/* The INITIAL_ELIMINATION_OFFSET worker.
   Calculate the difference between imaginary registers such as frame
   pointer and the stack pointer.  Used to eliminate the frame pointer
   and imaginary arg pointer.  */

int
cris_initial_elimination_offset (fromreg, toreg)
     int fromreg;
     int toreg;
{
  int fp_sp_offset
    = cris_initial_frame_pointer_offset ();

  /* We should be able to use regs_ever_live and related prologue
     information here, or alpha should not as well.  */
  int return_address_on_stack
    = regs_ever_live[CRIS_SRP_REGNUM]
    || cfun->machine->needs_return_address_on_stack != 0;

  /* Here we act as if the frame-pointer is needed.  */
  int ap_fp_offset = 4 + (return_address_on_stack ? 4 : 0);

  if (fromreg == ARG_POINTER_REGNUM
      && toreg == FRAME_POINTER_REGNUM)
    return ap_fp_offset;

  /* Between the frame pointer and the stack are only "normal" stack
     variables and saved registers.  */
  if (fromreg == FRAME_POINTER_REGNUM
      && toreg == STACK_POINTER_REGNUM)
    return fp_sp_offset;

  /* We need to balance out the frame pointer here.  */
  if (fromreg == ARG_POINTER_REGNUM
      && toreg == STACK_POINTER_REGNUM)
    return ap_fp_offset + fp_sp_offset - 4;

  abort ();
}

/*  This function looks into the pattern to see how this insn affects
    condition codes.

    Used when to eliminate test insns before a condition-code user,
    such as a "scc" insn or a conditional branch.  This includes
    checking if the entities that cc was updated by, are changed by the
    operation.

    Currently a jumble of the old peek-inside-the-insn and the newer
    check-cc-attribute methods.  */

void
cris_notice_update_cc (exp, insn)
     rtx exp;
     rtx insn;
{
  /* Check if user specified "-mcc-init" as a bug-workaround.  FIXME:
     TARGET_CCINIT does not work; we must set CC_REVERSED as below.
     Several test-cases will otherwise fail, for example
     gcc.c-torture/execute/20000217-1.c -O0 and -O1.  */
  if (TARGET_CCINIT)
    {
      CC_STATUS_INIT;
      return;
    }

  /* Slowly, we're converting to using attributes to control the setting
     of condition-code status.  */
  switch (get_attr_cc (insn))
    {
    case CC_NONE:
      /* Even if it is "none", a setting may clobber a previous
	 cc-value, so check.  */
      if (GET_CODE (exp) == SET)
	{
	  if (cc_status.value1
	      && cris_reg_overlap_mentioned_p (SET_DEST (exp),
					     cc_status.value1))
	    cc_status.value1 = 0;

	  if (cc_status.value2
	      && cris_reg_overlap_mentioned_p (SET_DEST (exp),
					     cc_status.value2))
	    cc_status.value2 = 0;
	}
      return;

    case CC_CLOBBER:
      CC_STATUS_INIT;
      break;

    case CC_NORMAL:
      /* Which means, for:
	 (set (cc0) (...)):
	 CC is (...).

	 (set (reg) (...)):
	 CC is (reg) and (...) - unless (...) is 0, then CC does not change.
	 CC_NO_OVERFLOW unless (...) is reg or mem.

	 (set (mem) (...)):
	 CC does not change.

	 (set (pc) (...)):
	 CC does not change.

	 (parallel
	  (set (reg1) (mem (bdap/biap)))
	  (set (reg2) (bdap/biap))):
	 CC is (reg1) and (mem (reg2))

	 (parallel
	  (set (mem (bdap/biap)) (reg1)) [or 0]
	  (set (reg2) (bdap/biap))):
	 CC does not change.

	 (where reg and mem includes strict_low_parts variants thereof)

	 For all others, assume CC is clobbered.
	 Note that we do not have to care about setting CC_NO_OVERFLOW,
	 since the overflow flag is set to 0 (i.e. right) for