bfin.c

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

      }
    while (value != 0);
}

/* Generate a LINK insn for a frame sized FRAME_SIZE.  If this constant
   is too large, generate a sequence of insns that has the same effect.
   SPREG contains (reg:SI REG_SP).  */

static void
emit_link_insn (rtx spreg, HOST_WIDE_INT frame_size)
{
  HOST_WIDE_INT link_size = frame_size;
  rtx insn;
  int i;

  if (link_size > 262140)
    link_size = 262140;

  /* Use a LINK insn with as big a constant as possible, then subtract
     any remaining size from the SP.  */
  insn = emit_insn (gen_link (GEN_INT (-8 - link_size)));
  RTX_FRAME_RELATED_P (insn) = 1;

  for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
    {
      rtx set = XVECEXP (PATTERN (insn), 0, i);
      if (GET_CODE (set) != SET)
	abort ();
      RTX_FRAME_RELATED_P (set) = 1;
    }

  frame_size -= link_size;

  if (frame_size > 0)
    {
      /* Must use a call-clobbered PREG that isn't the static chain.  */
      rtx tmpreg = gen_rtx_REG (Pmode, REG_P1);

      frame_related_constant_load (tmpreg, -frame_size);
      insn = emit_insn (gen_addsi3 (spreg, spreg, tmpreg));
      RTX_FRAME_RELATED_P (insn) = 1;
    }
}

/* Return the number of bytes we must reserve for outgoing arguments
   in the current function's stack frame.  */

static HOST_WIDE_INT
arg_area_size (void)
{
  if (current_function_outgoing_args_size)
    {
      if (current_function_outgoing_args_size >= FIXED_STACK_AREA)
	return current_function_outgoing_args_size;
      else
	return FIXED_STACK_AREA;
    }
  return 0;
}

/* Save RETS and FP, and allocate a stack frame.  */

static void
do_link (rtx spreg, HOST_WIDE_INT frame_size)
{
  frame_size += arg_area_size ();

  if (stack_frame_needed_p ()
      || (must_save_fp_p () && ! current_function_is_leaf))
    emit_link_insn (spreg, frame_size);
  else
    {
      if (! current_function_is_leaf)
	{
	  rtx pat = gen_movsi (gen_rtx_MEM (Pmode,
					    gen_rtx_PRE_DEC (Pmode, spreg)),
			       bfin_rets_rtx);
	  rtx insn = emit_insn (pat);
	  RTX_FRAME_RELATED_P (insn) = 1;
	}
      if (must_save_fp_p ())
	{
	  rtx pat = gen_movsi (gen_rtx_MEM (Pmode,
					    gen_rtx_PRE_DEC (Pmode, spreg)),
			       gen_rtx_REG (Pmode, REG_FP));
	  rtx insn = emit_insn (pat);
	  RTX_FRAME_RELATED_P (insn) = 1;
	}
      add_to_sp (spreg, -frame_size, 1);
    }
}

/* Like do_link, but used for epilogues to deallocate the stack frame.  */

static void
do_unlink (rtx spreg, HOST_WIDE_INT frame_size)
{
  frame_size += arg_area_size ();

  if (stack_frame_needed_p ())
    emit_insn (gen_unlink ());
  else 
    {
      rtx postinc = gen_rtx_MEM (Pmode, gen_rtx_POST_INC (Pmode, spreg));

      add_to_sp (spreg, frame_size, 0);
      if (must_save_fp_p ())
	{
	  rtx fpreg = gen_rtx_REG (Pmode, REG_FP);
	  emit_move_insn (fpreg, postinc);
	  emit_insn (gen_rtx_USE (VOIDmode, fpreg));
	}
      if (! current_function_is_leaf)
	{
	  emit_move_insn (bfin_rets_rtx, postinc);
	  emit_insn (gen_rtx_USE (VOIDmode, bfin_rets_rtx));
	}
    }
}

/* Generate a prologue suitable for a function of kind FKIND.  This is
   called for interrupt and exception handler prologues.
   SPREG contains (reg:SI REG_SP).  */

static void
expand_interrupt_handler_prologue (rtx spreg, e_funkind fkind)
{
  int i;
  HOST_WIDE_INT frame_size = get_frame_size ();
  rtx predec1 = gen_rtx_PRE_DEC (SImode, spreg);
  rtx predec = gen_rtx_MEM (SImode, predec1);
  rtx insn;
  tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl));
  tree all = lookup_attribute ("saveall", attrs);
  tree kspisusp = lookup_attribute ("kspisusp", attrs);

  if (kspisusp)
    {
      insn = emit_move_insn (spreg, gen_rtx_REG (Pmode, REG_USP));
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  /* We need space on the stack in case we need to save the argument
     registers.  */
  if (fkind == EXCPT_HANDLER)
    {
      insn = emit_insn (gen_addsi3 (spreg, spreg, GEN_INT (-12)));
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  insn = emit_move_insn (predec, gen_rtx_REG (SImode, REG_ASTAT));
  RTX_FRAME_RELATED_P (insn) = 1;

  expand_prologue_reg_save (spreg, all != NULL_TREE);

  for (i = REG_P7 + 1; i < REG_CC; i++)
    if (all 
	|| regs_ever_live[i]
	|| (!leaf_function_p () && call_used_regs[i]))
      {
	if (i == REG_A0 || i == REG_A1)
	  insn = emit_move_insn (gen_rtx_MEM (PDImode, predec1),
				 gen_rtx_REG (PDImode, i));
	else
	  insn = emit_move_insn (predec, gen_rtx_REG (SImode, i));
	RTX_FRAME_RELATED_P (insn) = 1;
      }

  if (lookup_attribute ("nesting", attrs))
    {
      rtx srcreg = gen_rtx_REG (Pmode, (fkind == EXCPT_HANDLER ? REG_RETX
					: fkind == NMI_HANDLER ? REG_RETN
					: REG_RETI));
      insn = emit_move_insn (predec, srcreg);
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  do_link (spreg, frame_size);

  if (fkind == EXCPT_HANDLER)
    {
      rtx r0reg = gen_rtx_REG (SImode, REG_R0);
      rtx r1reg = gen_rtx_REG (SImode, REG_R1);
      rtx r2reg = gen_rtx_REG (SImode, REG_R2);
      rtx insn;

      insn = emit_move_insn (r0reg, gen_rtx_REG (SImode, REG_SEQSTAT));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
      insn = emit_insn (gen_ashrsi3 (r0reg, r0reg, GEN_INT (26)));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
      insn = emit_insn (gen_ashlsi3 (r0reg, r0reg, GEN_INT (26)));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
      insn = emit_move_insn (r1reg, spreg);
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
      insn = emit_move_insn (r2reg, gen_rtx_REG (Pmode, REG_FP));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
      insn = emit_insn (gen_addsi3 (r2reg, r2reg, GEN_INT (8)));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx,
					    NULL_RTX);
    }
}

/* Generate an epilogue suitable for a function of kind FKIND.  This is
   called for interrupt and exception handler epilogues.
   SPREG contains (reg:SI REG_SP).  */

static void
expand_interrupt_handler_epilogue (rtx spreg, e_funkind fkind) 
{
  int i;
  rtx postinc1 = gen_rtx_POST_INC (SImode, spreg);
  rtx postinc = gen_rtx_MEM (SImode, postinc1);
  tree attrs = TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl));
  tree all = lookup_attribute ("saveall", attrs);

  /* A slightly crude technique to stop flow from trying to delete "dead"
     insns.  */
  MEM_VOLATILE_P (postinc) = 1;

  do_unlink (spreg, get_frame_size ());

  if (lookup_attribute ("nesting", attrs))
    {
      rtx srcreg = gen_rtx_REG (Pmode, (fkind == EXCPT_HANDLER ? REG_RETX
					: fkind == NMI_HANDLER ? REG_RETN
					: REG_RETI));
      emit_move_insn (srcreg, postinc);
    }

  for (i = REG_CC - 1; i > REG_P7; i--)
    if (all
	|| regs_ever_live[i] 
	|| (!leaf_function_p () && call_used_regs[i]))
      {
	if (i == REG_A0 || i == REG_A1)
	  {
	    rtx mem = gen_rtx_MEM (PDImode, postinc1);
	    MEM_VOLATILE_P (mem) = 1;
	    emit_move_insn (gen_rtx_REG (PDImode, i), mem);
	  }
	else
	  emit_move_insn (gen_rtx_REG (SImode, i), postinc);
      }

  expand_epilogue_reg_restore (spreg, all != NULL_TREE);

  emit_move_insn (gen_rtx_REG (SImode, REG_ASTAT), postinc);

  /* Deallocate any space we left on the stack in case we needed to save the
     argument registers.  */
  if (fkind == EXCPT_HANDLER)
    emit_insn (gen_addsi3 (spreg, spreg, GEN_INT (12)));

  emit_jump_insn (gen_return_internal (GEN_INT (fkind)));
}

/* Generate RTL for the prologue of the current function.  */

void
bfin_expand_prologue (void)
{
  rtx insn;
  HOST_WIDE_INT frame_size = get_frame_size ();
  rtx spreg = gen_rtx_REG (Pmode, REG_SP);
  e_funkind fkind = funkind (TREE_TYPE (current_function_decl));

  if (fkind != SUBROUTINE)
    {
      expand_interrupt_handler_prologue (spreg, fkind);
      return;
    }

  expand_prologue_reg_save (spreg, 0);

  do_link (spreg, frame_size);

  if (TARGET_ID_SHARED_LIBRARY
      && (current_function_uses_pic_offset_table
	  || !current_function_is_leaf))
    {
      rtx addr;
      
      if (bfin_library_id_string)
	addr = plus_constant (pic_offset_table_rtx, atoi (bfin_library_id_string));
      else
	addr = gen_rtx_PLUS (Pmode, pic_offset_table_rtx,
			     gen_rtx_UNSPEC (Pmode, gen_rtvec (1, const0_rtx),
					     UNSPEC_LIBRARY_OFFSET));
      insn = emit_insn (gen_movsi (pic_offset_table_rtx,
				   gen_rtx_MEM (Pmode, addr)));
      REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, const0_rtx, NULL);
    }
}

/* Generate RTL for the epilogue of the current function.  NEED_RETURN is zero
   if this is for a sibcall.  EH_RETURN is nonzero if we're expanding an
   eh_return pattern.  */

void
bfin_expand_epilogue (int need_return, int eh_return)
{
  rtx spreg = gen_rtx_REG (Pmode, REG_SP);
  e_funkind fkind = funkind (TREE_TYPE (current_function_decl));

  if (fkind != SUBROUTINE)
    {
      expand_interrupt_handler_epilogue (spreg, fkind);
      return;
    }

  do_unlink (spreg, get_frame_size ());

  expand_epilogue_reg_restore (spreg, 0);

  /* 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 (REG_P (op) || GET_CODE (op) == POST_INC
      || GET_CODE (op) == PRE_DEC || GET_CODE (op) == POST_DEC)
    return 0;
  if (GET_CODE (op) != PLUS)
    abort ();

  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)
{
  if (GET_CODE (x) == MEM) 
    abort ();

  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:
      print_operand (file, x, 0);
    }
}

/* 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;