m68hc11.c

Mac OS X 10.4.9 for x86 Source Code gcc 实现源代码

  func_attr = TYPE_ATTRIBUTES (TREE_TYPE (decl));


  if (lookup_attribute ("far", func_attr) != NULL_TREE)
    is_far = 1;
  else if (lookup_attribute ("near", func_attr) == NULL_TREE)
    is_far = TARGET_LONG_CALLS != 0;

  trap_handler = lookup_attribute ("trap", func_attr) != NULL_TREE;
  if (trap_handler && is_far)
    {
      warning ("%<trap%> and %<far%> attributes are not compatible, ignoring %<far%>");
      trap_handler = 0;
    }
  if (trap_handler)
    {
      if (trap_handler_symbol != 0)
        warning ("%<trap%> attribute is already used");
      else
        trap_handler_symbol = XEXP (rtl, 0);
    }
  SYMBOL_REF_FLAG (XEXP (rtl, 0)) = is_far;
}

static unsigned int
m68hc11_section_type_flags (tree decl, const char *name, int reloc)
{
  unsigned int flags = default_section_type_flags (decl, name, reloc);

  if (strncmp (name, ".eeprom", 7) == 0)
    {
      flags |= SECTION_WRITE | SECTION_CODE | SECTION_OVERRIDE;
    }

  return flags;
}

int
m68hc11_is_far_symbol (rtx sym)
{
  if (GET_CODE (sym) == MEM)
    sym = XEXP (sym, 0);

  return SYMBOL_REF_FLAG (sym);
}

int
m68hc11_is_trap_symbol (rtx sym)
{
  if (GET_CODE (sym) == MEM)
    sym = XEXP (sym, 0);

  return trap_handler_symbol != 0 && rtx_equal_p (trap_handler_symbol, sym);
}


/* Argument support functions.  */

/* Define the offset between two registers, one to be eliminated, and the
   other its replacement, at the start of a routine.  */
int
m68hc11_initial_elimination_offset (int from, int to)
{
  int trap_handler;
  tree func_attr;
  int size;
  int regno;

  /* For a trap handler, we must take into account the registers which
     are pushed on the stack during the trap (except the PC).  */
  func_attr = TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl));
  current_function_interrupt = lookup_attribute ("interrupt",
						 func_attr) != NULL_TREE;
  trap_handler = lookup_attribute ("trap", func_attr) != NULL_TREE;

  if (lookup_attribute ("far", func_attr) != 0)
    current_function_far = 1;
  else if (lookup_attribute ("near", func_attr) != 0)
    current_function_far = 0;
  else
    current_function_far = (TARGET_LONG_CALLS != 0
                            && !current_function_interrupt
                            && !trap_handler);

  if (trap_handler && from == ARG_POINTER_REGNUM)
    size = 7;

  /* For a function using 'call/rtc' we must take into account the
     page register which is pushed in the call.  */
  else if (current_function_far && from == ARG_POINTER_REGNUM)
    size = 1;
  else
    size = 0;

  if (from == ARG_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
    {
      /* 2 is for the saved frame.
         1 is for the 'sts' correction when creating the frame.  */
      return get_frame_size () + 2 + m68hc11_sp_correction + size;
    }

  if (from == FRAME_POINTER_REGNUM && to == HARD_FRAME_POINTER_REGNUM)
    {
      return m68hc11_sp_correction;
    }

  /* Push any 2 byte pseudo hard registers that we need to save.  */
  for (regno = SOFT_REG_FIRST; regno < SOFT_REG_LAST; regno++)
    {
      if (regs_ever_live[regno] && !call_used_regs[regno])
	{
	  size += 2;
	}
    }

  if (from == ARG_POINTER_REGNUM && to == HARD_SP_REGNUM)
    {
      return get_frame_size () + size;
    }

  if (from == FRAME_POINTER_REGNUM && to == HARD_SP_REGNUM)
    {
      return size;
    }
  return 0;
}

/* 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.  */

void
m68hc11_init_cumulative_args (CUMULATIVE_ARGS *cum, tree fntype, rtx libname)
{
  tree ret_type;

  z_replacement_completed = 0;
  cum->words = 0;
  cum->nregs = 0;

  /* For a library call, we must find out the type of the return value.
     When the return value is bigger than 4 bytes, it is returned in
     memory.  In that case, the first argument of the library call is a
     pointer to the memory location.  Because the first argument is passed in
     register D, we have to identify this, so that the first function
     parameter is not passed in D either.  */
  if (fntype == 0)
    {
      const char *name;
      size_t len;

      if (libname == 0 || GET_CODE (libname) != SYMBOL_REF)
	return;

      /* If the library ends in 'di' or in 'df', we assume it's
         returning some DImode or some DFmode which are 64-bit wide.  */
      name = XSTR (libname, 0);
      len = strlen (name);
      if (len > 3
	  && ((name[len - 2] == 'd'
	       && (name[len - 1] == 'f' || name[len - 1] == 'i'))
	      || (name[len - 3] == 'd'
		  && (name[len - 2] == 'i' || name[len - 2] == 'f'))))
	{
	  /* We are in.  Mark the first parameter register as already used.  */
	  cum->words = 1;
	  cum->nregs = 1;
	}
      return;
    }

  ret_type = TREE_TYPE (fntype);

  if (ret_type && aggregate_value_p (ret_type, fntype))
    {
      cum->words = 1;
      cum->nregs = 1;
    }
}

/* 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
m68hc11_function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode,
                              tree type, int named ATTRIBUTE_UNUSED)
{
  if (mode != BLKmode)
    {
      if (cum->words == 0 && GET_MODE_SIZE (mode) == 4)
	{
	  cum->nregs = 2;
	  cum->words = GET_MODE_SIZE (mode);
	}
      else
	{
	  cum->words += GET_MODE_SIZE (mode);
	  if (cum->words <= HARD_REG_SIZE)
	    cum->nregs = 1;
	}
    }
  else
    {
      cum->words += int_size_in_bytes (type);
    }
  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 *
m68hc11_function_arg (const CUMULATIVE_ARGS *cum, enum machine_mode mode,
                      tree type ATTRIBUTE_UNUSED, int named ATTRIBUTE_UNUSED)
{
  if (cum->words != 0)
    {
      return NULL_RTX;
    }

  if (mode != BLKmode)
    {
      if (GET_MODE_SIZE (mode) == 2 * HARD_REG_SIZE)
	return gen_rtx_REG (mode, HARD_X_REGNUM);

      if (GET_MODE_SIZE (mode) > HARD_REG_SIZE)
	{
	  return NULL_RTX;
	}
      return gen_rtx_REG (mode, HARD_D_REGNUM);
    }
  return NULL_RTX;
}

/* If defined, a C expression which determines whether, and in which direction,
   to pad out an argument with extra space.  The value should be of type
   `enum direction': either `upward' to pad above the argument,
   `downward' to pad below, or `none' to inhibit padding.

   Structures are stored left shifted in their argument slot.  */
int
m68hc11_function_arg_padding (enum machine_mode mode, tree type)
{
  if (type != 0 && AGGREGATE_TYPE_P (type))
    return upward;

  /* Fall back to the default.  */
  return DEFAULT_FUNCTION_ARG_PADDING (mode, type);
}


/* Function prologue and epilogue.  */

/* Emit a move after the reload pass has completed.  This is used to
   emit the prologue and epilogue.  */
static void
emit_move_after_reload (rtx to, rtx from, rtx scratch)
{
  rtx insn;

  if (TARGET_M6812 || H_REG_P (to) || H_REG_P (from))
    {
      insn = emit_move_insn (to, from);
    }
  else
    {
      emit_move_insn (scratch, from);
      insn = emit_move_insn (to, scratch);
    }

  /* Put a REG_INC note to tell the flow analysis that the instruction
     is necessary.  */
  if (IS_STACK_PUSH (to))
    {
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC,
					    XEXP (XEXP (to, 0), 0),
					    REG_NOTES (insn));
    }
  else if (IS_STACK_POP (from))
    {
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC,
					    XEXP (XEXP (from, 0), 0),
					    REG_NOTES (insn));
    }

  /* For 68HC11, put a REG_INC note on `sts _.frame' to prevent the cse-reg
     to think that sp == _.frame and later replace a x = sp with x = _.frame.
     The problem is that we are lying to gcc and use `txs' for x = sp
     (which is not really true because txs is really x = sp + 1).  */
  else if (TARGET_M6811 && SP_REG_P (from))
    {
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_INC,
					    from,
					    REG_NOTES (insn));
    }
}

int
m68hc11_total_frame_size (void)
{
  int size;
  int regno;

  size = get_frame_size ();
  if (current_function_interrupt)
    {
      size += 3 * HARD_REG_SIZE;
    }
  if (frame_pointer_needed)
    size += HARD_REG_SIZE;

  for (regno = SOFT_REG_FIRST; regno <= SOFT_REG_LAST; regno++)
    if (regs_ever_live[regno] && !call_used_regs[regno])
      size += HARD_REG_SIZE;

  return size;
}

static void
m68hc11_output_function_epilogue (FILE *out ATTRIBUTE_UNUSED,
                                  HOST_WIDE_INT size ATTRIBUTE_UNUSED)
{
  /* We catch the function epilogue generation to have a chance
     to clear the z_replacement_completed flag.  */
  z_replacement_completed = 0;
}

void
expand_prologue (void)
{
  tree func_attr;
  int size;
  int regno;
  rtx scratch;

  if (reload_completed != 1)
    abort ();

  size = get_frame_size ();

  create_regs_rtx ();

  /* Generate specific prologue for interrupt handlers.  */
  func_attr = TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl));
  current_function_interrupt = lookup_attribute ("interrupt",
						 func_attr) != NULL_TREE;
  current_function_trap = lookup_attribute ("trap", func_attr) != NULL_TREE;
  if (lookup_attribute ("far", func_attr) != NULL_TREE)
    current_function_far = 1;
  else if (lookup_attribute ("near", func_attr) != NULL_TREE)
    current_function_far = 0;
  else
    current_function_far = (TARGET_LONG_CALLS != 0
                            && !current_function_interrupt
                            && !current_function_trap);

  /* Get the scratch register to build the frame and push registers.
     If the first argument is a 32-bit quantity, the D+X registers
     are used.  Use Y to compute the frame.  Otherwise, X is cheaper.
     For 68HC12, this scratch register is not used.  */
  if (current_function_args_info.nregs == 2)
    scratch = iy_reg;
  else
    scratch = ix_reg;

  /* Save current stack frame.  */
  if (frame_pointer_needed)
    emit_move_after_reload (stack_push_word, hard_frame_pointer_rtx, scratch);

  /* For an interrupt handler, we must preserve _.tmp, _.z and _.xy.
     Other soft registers in page0 need not to be saved because they
     will be restored by C functions.  For a trap handler, we don't
     need to preserve these registers because this is a synchronous call.  */
  if (current_function_interrupt)
    {
      emit_move_after_reload (stack_push_word, m68hc11_soft_tmp_reg, scratch);
      emit_move_after_reload (stack_push_word,
			      gen_rtx_REG (HImode, SOFT_Z_REGNUM), scratch);
      emit_move_after_reload (stack_push_word,
			      gen_rtx_REG (HImode, SOFT_SAVED_XY_REGNUM),
			      scratch);
    }

  /* Allocate local variables.  */
  if (TARGET_M6812 && (size > 4 || size == 3))
    {
      emit_insn (gen_addhi3 (stack_pointer_rtx,
			     stack_pointer_rtx, GEN_INT (-size)));
    }
  else if ((!optimize_size && size > 8) || (optimize_size && size > 10))
    {
      rtx insn;

      insn = gen_rtx_PARALLEL
	(VOIDmode,
	 gen_rtvec (2,
		    gen_rtx_SET (VOIDmode,
				 stack_pointer_rtx,
				 gen_rtx_PLUS (HImode,
					       stack_pointer_rtx,
					       GEN_INT (-size))),
		    gen_rtx_CLOBBER (VOIDmode, scratch)));
      emit_insn (insn);
    }
  else
    {
      int i;

      /* Allocate by pushing scratch values.  */
      for (i = 2; i <= size; i += 2)
	emit_move_after_reload (stack_push_word, ix_reg, 0);

      if (size & 1)
	emit_insn (gen_addhi3 (stack_pointer_rtx,
			       stack_pointer_rtx, constm1_rtx));
    }

  /* Create the frame pointer.  */
  if (frame_pointer_needed)
    emit_move_after_reload (hard_frame_pointer_rtx,
			    stack_pointer_rtx, scratch);

  /* Push any 2 byte pseudo hard registers that we need to save.  */
  for (regno = SOFT_REG_FIRST; regno <= SOFT_REG_LAST; regno++)
    {
      if (regs_ever_live[regno] && !call_used_regs[regno])
	{
	  emit_move_after_reload (stack_push_word,
				  gen_rtx_REG (HImode, regno), scratch);
	}
    }
}

void
expand_epilogue (void)
{
  int size;
  register int regno;
  int return_size;
  rtx scratch;

  if (reload_completed != 1)
    abort ();

  size = get_frame_size ();

  /* If we are returning a value in two registers, we have to preserve the
     X register and use the Y register to restore the stack and the saved
     registers.  Otherwise, use X because it's faster (and smaller).  */
  if (current_function_return_rtx == 0)
    return_size = 0;
  else if (GET_CODE (current_function_return_rtx) == MEM)
    return_size = HARD_REG_SIZE;
  else
    return_size = GET_MODE_SIZE (GET_MODE (current_function_return_rtx));

  if (return_size > HARD_REG_SIZE && return_size <= 2 * HARD_REG_SIZE)
    scratch = iy_reg;
  else
    scratch = ix_reg;

  /* Pop any 2 byte pseudo hard registers that we saved.  */
  for (regno = SOFT_REG_LAST; regno >= SOFT_REG_FIRST; regno--)
    {
      if (regs_ever_live[regno] && !call_used_regs[regno])