bfin.c

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  do_unlink (spreg, get_frame_size (), false);

  expand_epilogue_reg_restore (spreg, false, false);

  /* Omit the return insn if this is for a sibcall.  */
  if (! need_return)
    return;

  if (eh_return)
    emit_insn (gen_addsi3 (spreg, spreg, gen_rtx_REG (Pmode, REG_P2)));

  emit_jump_insn (gen_return_internal (GEN_INT (SUBROUTINE)));
}

/* Return nonzero if register OLD_REG can be renamed to register NEW_REG.  */

int
bfin_hard_regno_rename_ok (unsigned int old_reg ATTRIBUTE_UNUSED,
			   unsigned int new_reg)
{
  /* Interrupt functions can only use registers that have already been
     saved by the prologue, even if they would normally be
     call-clobbered.  */

  if (funkind (TREE_TYPE (current_function_decl)) != SUBROUTINE
      && !regs_ever_live[new_reg])
    return 0;

  return 1;
}

/* Return the value of the return address for the frame COUNT steps up
   from the current frame, after the prologue.
   We punt for everything but the current frame by returning const0_rtx.  */

rtx
bfin_return_addr_rtx (int count)
{
  if (count != 0)
    return const0_rtx;

  return get_hard_reg_initial_val (Pmode, REG_RETS);
}

/* Try machine-dependent ways of modifying an illegitimate address X
   to be legitimate.  If we find one, return the new, valid address,
   otherwise return NULL_RTX.

   OLDX is the address as it was before break_out_memory_refs was called.
   In some cases it is useful to look at this to decide what needs to be done.

   MODE is the mode of the memory reference.  */

rtx
legitimize_address (rtx x ATTRIBUTE_UNUSED, rtx oldx ATTRIBUTE_UNUSED,
		    enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return NULL_RTX;
}

/* This predicate is used to compute the length of a load/store insn.
   OP is a MEM rtx, we return nonzero if its addressing mode requires a
   32 bit instruction.  */

int
effective_address_32bit_p (rtx op, enum machine_mode mode) 
{
  HOST_WIDE_INT offset;

  mode = GET_MODE (op);
  op = XEXP (op, 0);

  if (GET_CODE (op) != PLUS)
    {
      gcc_assert (REG_P (op) || GET_CODE (op) == POST_INC
		  || GET_CODE (op) == PRE_DEC || GET_CODE (op) == POST_DEC);
      return 0;
    }

  offset = INTVAL (XEXP (op, 1));

  /* All byte loads use a 16 bit offset.  */
  if (GET_MODE_SIZE (mode) == 1)
    return 1;

  if (GET_MODE_SIZE (mode) == 4)
    {
      /* Frame pointer relative loads can use a negative offset, all others
	 are restricted to a small positive one.  */
      if (XEXP (op, 0) == frame_pointer_rtx)
	return offset < -128 || offset > 60;
      return offset < 0 || offset > 60;
    }

  /* Must be HImode now.  */
  return offset < 0 || offset > 30;
}

/* Return cost of the memory address ADDR.
   All addressing modes are equally cheap on the Blackfin.  */

static int
bfin_address_cost (rtx addr ATTRIBUTE_UNUSED)
{
  return 1;
}

/* Subroutine of print_operand; used to print a memory reference X to FILE.  */

void
print_address_operand (FILE *file, rtx x)
{
  switch (GET_CODE (x))
    {
    case PLUS:
      output_address (XEXP (x, 0));
      fprintf (file, "+");
      output_address (XEXP (x, 1));
      break;

    case PRE_DEC:
      fprintf (file, "--");
      output_address (XEXP (x, 0));    
      break;
    case POST_INC:
      output_address (XEXP (x, 0));
      fprintf (file, "++");
      break;
    case POST_DEC:
      output_address (XEXP (x, 0));
      fprintf (file, "--");
      break;

    default:
      gcc_assert (GET_CODE (x) != MEM);
      print_operand (file, x, 0);
      break;
    }
}

/* Adding intp DImode support by Tony
 * -- Q: (low  word)
 * -- R: (high word)
 */

void
print_operand (FILE *file, rtx x, char code)
{
  enum machine_mode mode = GET_MODE (x);

  switch (code)
    {
    case 'j':
      switch (GET_CODE (x))
	{
	case EQ:
	  fprintf (file, "e");
	  break;
	case NE:
	  fprintf (file, "ne");
	  break;
	case GT:
	  fprintf (file, "g");
	  break;
	case LT:
	  fprintf (file, "l");
	  break;
	case GE:
	  fprintf (file, "ge");
	  break;
	case LE:
	  fprintf (file, "le");
	  break;
	case GTU:
	  fprintf (file, "g");
	  break;
	case LTU:
	  fprintf (file, "l");
	  break;
	case GEU:
	  fprintf (file, "ge");
	  break;
	case LEU:
	  fprintf (file, "le");
	  break;
	default:
	  output_operand_lossage ("invalid %%j value");
	}
      break;
    
    case 'J':					 /* reverse logic */
      switch (GET_CODE(x))
	{
	case EQ:
	  fprintf (file, "ne");
	  break;
	case NE:
	  fprintf (file, "e");
	  break;
	case GT:
	  fprintf (file, "le");
	  break;
	case LT:
	  fprintf (file, "ge");
	  break;
	case GE:
	  fprintf (file, "l");
	  break;
	case LE:
	  fprintf (file, "g");
	  break;
	case GTU:
	  fprintf (file, "le");
	  break;
	case LTU:
	  fprintf (file, "ge");
	  break;
	case GEU:
	  fprintf (file, "l");
	  break;
	case LEU:
	  fprintf (file, "g");
	  break;
	default:
	  output_operand_lossage ("invalid %%J value");
	}
      break;

    default:
      switch (GET_CODE (x))
	{
	case REG:
	  if (code == 'h')
	    {
	      gcc_assert (REGNO (x) < 32);
	      fprintf (file, "%s", short_reg_names[REGNO (x)]);
	      /*fprintf (file, "\n%d\n ", REGNO (x));*/
	      break;
	    }
	  else if (code == 'd')
	    {
	      gcc_assert (REGNO (x) < 32);
	      fprintf (file, "%s", high_reg_names[REGNO (x)]);
	      break;
	    }
	  else if (code == 'w')
	    {
	      gcc_assert (REGNO (x) == REG_A0 || REGNO (x) == REG_A1);
	      fprintf (file, "%s.w", reg_names[REGNO (x)]);
	    }
	  else if (code == 'x')
	    {
	      gcc_assert (REGNO (x) == REG_A0 || REGNO (x) == REG_A1);
	      fprintf (file, "%s.x", reg_names[REGNO (x)]);
	    }
	  else if (code == 'D')
	    {
	      fprintf (file, "%s", dregs_pair_names[REGNO (x)]);
	    }
	  else if (code == 'H')
	    {
	      gcc_assert (mode == DImode || mode == DFmode);
	      gcc_assert (REG_P (x));
	      fprintf (file, "%s", reg_names[REGNO (x) + 1]);
	    }
	  else if (code == 'T')
	    {
	      gcc_assert (D_REGNO_P (REGNO (x)));
	      fprintf (file, "%s", byte_reg_names[REGNO (x)]);
	    }
	  else 
	    fprintf (file, "%s", reg_names[REGNO (x)]);
	  break;

	case MEM:
	  fputc ('[', file);
	  x = XEXP (x,0);
	  print_address_operand (file, x);
	  fputc (']', file);
	  break;

	case CONST_INT:
	  /* Moves to half registers with d or h modifiers always use unsigned
	     constants.  */
	  if (code == 'd')
	    x = GEN_INT ((INTVAL (x) >> 16) & 0xffff);
	  else if (code == 'h')
	    x = GEN_INT (INTVAL (x) & 0xffff);
	  else if (code == 'X')
	    x = GEN_INT (exact_log2 (0xffffffff & INTVAL (x)));
	  else if (code == 'Y')
	    x = GEN_INT (exact_log2 (0xffffffff & ~INTVAL (x)));
	  else if (code == 'Z')
	    /* Used for LINK insns.  */
	    x = GEN_INT (-8 - INTVAL (x));

	  /* fall through */

	case SYMBOL_REF:
	  output_addr_const (file, x);
	  if (code == 'G' && flag_pic)
	    fprintf (file, "@GOT");
	  break;

	case CONST_DOUBLE:
	  output_operand_lossage ("invalid const_double operand");
	  break;

	case UNSPEC:
	  switch (XINT (x, 1))
	    {
	    case UNSPEC_MOVE_PIC:
	      output_addr_const (file, XVECEXP (x, 0, 0));
	      fprintf (file, "@GOT");
	      break;

	    case UNSPEC_LIBRARY_OFFSET:
	      fprintf (file, "_current_shared_library_p5_offset_");
	      break;

	    default:
	      gcc_unreachable ();
	    }
	  break;

	default:
	  output_addr_const (file, x);
	}
    }
}

/* Argument support functions.  */

/* Initialize a variable CUM of type CUMULATIVE_ARGS
   for a call to a function whose data type is FNTYPE.
   For a library call, FNTYPE is 0.  
   VDSP C Compiler manual, our ABI says that
   first 3 words of arguments will use R0, R1 and R2.
*/

void
init_cumulative_args (CUMULATIVE_ARGS *cum, tree fntype,
		      rtx libname ATTRIBUTE_UNUSED)
{
  static CUMULATIVE_ARGS zero_cum;

  *cum = zero_cum;

  /* Set up the number of registers to use for passing arguments.  */

  cum->nregs = max_arg_registers;
  cum->arg_regs = arg_regs;

  cum->call_cookie = CALL_NORMAL;
  /* Check for a longcall attribute.  */
  if (fntype && lookup_attribute ("shortcall", TYPE_ATTRIBUTES (fntype)))
    cum->call_cookie |= CALL_SHORT;
  else if (fntype && lookup_attribute ("longcall", TYPE_ATTRIBUTES (fntype)))
    cum->call_cookie |= CALL_LONG;

  return;
}

/* Update the data in CUM to advance over an argument
   of mode MODE and data type TYPE.
   (TYPE is null for libcalls where that information may not be available.)  */

void
function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode, tree type,
		      int named ATTRIBUTE_UNUSED)
{
  int count, bytes, words;

  bytes = (mode == BLKmode) ? int_size_in_bytes (type) : GET_MODE_SIZE (mode);
  words = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;

  cum->words += words;
  cum->nregs -= words;

  if (cum->nregs <= 0)
    {
      cum->nregs = 0;
      cum->arg_regs = NULL;
    }
  else
    {
      for (count = 1; count <= words; count++)
        cum->arg_regs++;
    }

  return;
}

/* Define where to put the arguments to a function.
   Value is zero to push the argument on the stack,
   or a hard register in which to store the argument.

   MODE is the argument's machine mode.
   TYPE is the data type of the argument (as a tree).
    This is null for libcalls where that information may
    not be available.
   CUM is a variable of type CUMULATIVE_ARGS which gives info about
    the preceding args and about the function being called.
   NAMED is nonzero if this argument is a named parameter
    (otherwise it is an extra parameter matching an ellipsis).  */

struct rtx_def *
function_arg (CUMULATIVE_ARGS *cum, enum machine_mode mode, tree type,
	      int named ATTRIBUTE_UNUSED)
{
  int bytes
    = (mode == BLKmode) ? int_size_in_bytes (type) : GET_MODE_SIZE (mode);

  if (mode == VOIDmode)
    /* Compute operand 2 of the call insn.  */
    return GEN_INT (cum->call_cookie);

  if (bytes == -1)
    return NULL_RTX;

  if (cum->nregs)
    return gen_rtx_REG (mode, *(cum->arg_regs));

  return NULL_RTX;
}

/* For an arg passed partly in registers and partly in memory,
   this is the number of bytes passed in registers.
   For args passed entirely in registers or entirely in memory, zero.

   Refer VDSP C Compiler manual, our ABI.
   First 3 words are in registers. So, if a an argument is larger
   than the registers available, it will span the register and
   stack.   */

static int
bfin_arg_partial_bytes (CUMULATIVE_ARGS *cum, enum machine_mode mode,
			tree type ATTRIBUTE_UNUSED,
			bool named ATTRIBUTE_UNUSED)
{
  int bytes
    = (mode == BLKmode) ? int_size_in_bytes (type) : GET_MODE_SIZE (mode);
  int bytes_left = cum->nregs * UNITS_PER_WORD;
  
  if (bytes == -1)
    return 0;

  if (bytes_left == 0)
    return 0;
  if (bytes > bytes_left)
    return bytes_left;
  return 0;
}

/* Variable sized types are passed by reference.  */

static bool
bfin_pass_by_reference (CUMULATIVE_ARGS *cum ATTRIBUTE_UNUSED,
			enum machine_mode mode ATTRIBUTE_UNUSED,
			tree type, bool named ATTRIBUTE_UNUSED)
{
  return type && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST;
}

/* Decide whether a type should be returned in memory (true)
   or in a register (false).  This is called by the macro
   RETURN_IN_MEMORY.  */

int
bfin_return_in_memory (tree type)
{
  int size = int_size_in_bytes (type);
  return size > 2 * UNITS_PER_WORD || size == -1;
}

/* Register in which address to store a structure value
   is passed to a function.  */
static rtx
bfin_struct_value_rtx (tree fntype ATTRIBUTE_UNUSED,
		      int incoming ATTRIBUTE_UNUSED)
{
  return gen_rtx_REG (Pmode, REG_P0);
}