arm.c

gcc-2.95.3 Linux下最常用的C编译器

  if (!fpa_consts_inited)
    init_fpa_table ();
  
  REAL_VALUE_FROM_CONST_DOUBLE (r, x);
  if (REAL_VALUE_MINUS_ZERO (r))
    return 0;

  for (i = 0; i < 8; i++)
    if (REAL_VALUES_EQUAL (r, values_fpa[i]))
      return 1;

  return 0;
}

/* Return TRUE if rtx X is a valid immediate FPU constant. */

int
neg_const_double_rtx_ok_for_fpu (x)
     rtx x;
{
  REAL_VALUE_TYPE r;
  int i;
  
  if (!fpa_consts_inited)
    init_fpa_table ();
  
  REAL_VALUE_FROM_CONST_DOUBLE (r, x);
  r = REAL_VALUE_NEGATE (r);
  if (REAL_VALUE_MINUS_ZERO (r))
    return 0;

  for (i = 0; i < 8; i++)
    if (REAL_VALUES_EQUAL (r, values_fpa[i]))
      return 1;

  return 0;
}

/* Predicates for `match_operand' and `match_operator'.  */

/* s_register_operand is the same as register_operand, but it doesn't accept
   (SUBREG (MEM)...).

   This function exists because at the time it was put in it led to better
   code.  SUBREG(MEM) always needs a reload in the places where
   s_register_operand is used, and this seemed to lead to excessive
   reloading.  */

int
s_register_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  if (GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  /* We don't consider registers whose class is NO_REGS
     to be a register operand.  */
  return (GET_CODE (op) == REG
	  && (REGNO (op) >= FIRST_PSEUDO_REGISTER
	      || REGNO_REG_CLASS (REGNO (op)) != NO_REGS));
}

/* Only accept reg, subreg(reg), const_int.  */

int
reg_or_int_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  if (GET_CODE (op) == CONST_INT)
    return 1;

  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  if (GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  /* We don't consider registers whose class is NO_REGS
     to be a register operand.  */
  return (GET_CODE (op) == REG
	  && (REGNO (op) >= FIRST_PSEUDO_REGISTER
	      || REGNO_REG_CLASS (REGNO (op)) != NO_REGS));
}

/* Return 1 if OP is an item in memory, given that we are in reload.  */

int
reload_memory_operand (op, mode)
     rtx op;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  int regno = true_regnum (op);

  return (! CONSTANT_P (op)
	  && (regno == -1
	      || (GET_CODE (op) == REG
		  && REGNO (op) >= FIRST_PSEUDO_REGISTER)));
}

/* Return 1 if OP is a valid memory address, but not valid for a signed byte
   memory access (architecture V4) */
int
bad_signed_byte_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (! memory_operand (op, mode) || GET_CODE (op) != MEM)
    return 0;

  op = XEXP (op, 0);

  /* A sum of anything more complex than reg + reg or reg + const is bad */
  if ((GET_CODE (op) == PLUS || GET_CODE (op) == MINUS)
      && (! s_register_operand (XEXP (op, 0), VOIDmode)
	  || (! s_register_operand (XEXP (op, 1), VOIDmode)
	      && GET_CODE (XEXP (op, 1)) != CONST_INT)))
    return 1;

  /* Big constants are also bad */
  if (GET_CODE (op) == PLUS && GET_CODE (XEXP (op, 1)) == CONST_INT
      && (INTVAL (XEXP (op, 1)) > 0xff
	  || -INTVAL (XEXP (op, 1)) > 0xff))
    return 1;

  /* Everything else is good, or can will automatically be made so. */
  return 0;
}

/* Return TRUE for valid operands for the rhs of an ARM instruction.  */

int
arm_rhs_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (s_register_operand (op, mode)
	  || (GET_CODE (op) == CONST_INT && const_ok_for_arm (INTVAL (op))));
}

/* Return TRUE for valid operands for the rhs of an ARM instruction, or a load.
 */

int
arm_rhsm_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (s_register_operand (op, mode)
	  || (GET_CODE (op) == CONST_INT && const_ok_for_arm (INTVAL (op)))
	  || memory_operand (op, mode));
}

/* Return TRUE for valid operands for the rhs of an ARM instruction, or if a
   constant that is valid when negated.  */

int
arm_add_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (s_register_operand (op, mode)
	  || (GET_CODE (op) == CONST_INT
	      && (const_ok_for_arm (INTVAL (op))
		  || const_ok_for_arm (-INTVAL (op)))));
}

int
arm_not_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (s_register_operand (op, mode)
	  || (GET_CODE (op) == CONST_INT
	      && (const_ok_for_arm (INTVAL (op))
		  || const_ok_for_arm (~INTVAL (op)))));
}

/* Return TRUE if the operand is a memory reference which contains an
   offsettable address.  */
int
offsettable_memory_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  if (mode == VOIDmode)
    mode = GET_MODE (op);

  return (mode == GET_MODE (op)
	  && GET_CODE (op) == MEM
	  && offsettable_address_p (reload_completed | reload_in_progress,
				    mode, XEXP (op, 0)));
}

/* Return TRUE if the operand is a memory reference which is, or can be
   made word aligned by adjusting the offset.  */
int
alignable_memory_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  rtx reg;

  if (mode == VOIDmode)
    mode = GET_MODE (op);

  if (mode != GET_MODE (op) || GET_CODE (op) != MEM)
    return 0;

  op = XEXP (op, 0);

  return ((GET_CODE (reg = op) == REG
	   || (GET_CODE (op) == SUBREG
	       && GET_CODE (reg = SUBREG_REG (op)) == REG)
	   || (GET_CODE (op) == PLUS
	       && GET_CODE (XEXP (op, 1)) == CONST_INT
	       && (GET_CODE (reg = XEXP (op, 0)) == REG
		   || (GET_CODE (XEXP (op, 0)) == SUBREG
		       && GET_CODE (reg = SUBREG_REG (XEXP (op, 0))) == REG))))
	  && REGNO_POINTER_ALIGN (REGNO (reg)) >= 4);
}

/* Similar to s_register_operand, but does not allow hard integer 
   registers.  */
int
f_register_operand (op, mode)
     register rtx op;
     enum machine_mode mode;
{
  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  if (GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  /* We don't consider registers whose class is NO_REGS
     to be a register operand.  */
  return (GET_CODE (op) == REG
	  && (REGNO (op) >= FIRST_PSEUDO_REGISTER
	      || REGNO_REG_CLASS (REGNO (op)) == FPU_REGS));
}

/* Return TRUE for valid operands for the rhs of an FPU instruction.  */

int
fpu_rhs_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (s_register_operand (op, mode))
    return TRUE;
  else if (GET_CODE (op) == CONST_DOUBLE)
    return (const_double_rtx_ok_for_fpu (op));

  return FALSE;
}

int
fpu_add_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (s_register_operand (op, mode))
    return TRUE;
  else if (GET_CODE (op) == CONST_DOUBLE)
    return (const_double_rtx_ok_for_fpu (op) 
	    || neg_const_double_rtx_ok_for_fpu (op));

  return FALSE;
}

/* Return nonzero if OP is a constant power of two.  */

int
power_of_two_operand (op, mode)
     rtx op;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  if (GET_CODE (op) == CONST_INT)
    {
      HOST_WIDE_INT value = INTVAL(op);
      return value != 0  &&  (value & (value - 1)) == 0;
    }
  return FALSE;
}

/* Return TRUE for a valid operand of a DImode operation.
   Either: REG, SUBREG, CONST_DOUBLE or MEM(DImode_address).
   Note that this disallows MEM(REG+REG), but allows
   MEM(PRE/POST_INC/DEC(REG)).  */

int
di_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (s_register_operand (op, mode))
    return TRUE;

  if (GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  switch (GET_CODE (op))
    {
    case CONST_DOUBLE:
    case CONST_INT:
      return TRUE;

    case MEM:
      return memory_address_p (DImode, XEXP (op, 0));

    default:
      return FALSE;
    }
}

/* Return TRUE for a valid operand of a DFmode operation when -msoft-float.
   Either: REG, SUBREG, CONST_DOUBLE or MEM(DImode_address).
   Note that this disallows MEM(REG+REG), but allows
   MEM(PRE/POST_INC/DEC(REG)).  */

int
soft_df_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  if (s_register_operand (op, mode))
    return TRUE;

  if (GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  switch (GET_CODE (op))
    {
    case CONST_DOUBLE:
      return TRUE;

    case MEM:
      return memory_address_p (DFmode, XEXP (op, 0));

    default:
      return FALSE;
    }
}

/* Return TRUE for valid index operands. */

int
index_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (s_register_operand(op, mode)
	  || (immediate_operand (op, mode)
	      && INTVAL (op) < 4096 && INTVAL (op) > -4096));
}

/* Return TRUE for valid shifts by a constant. This also accepts any
   power of two on the (somewhat overly relaxed) assumption that the
   shift operator in this case was a mult. */

int
const_shift_operand (op, mode)
     rtx op;
     enum machine_mode mode;
{
  return (power_of_two_operand (op, mode)
	  || (immediate_operand (op, mode)
	      && (INTVAL (op) < 32 && INTVAL (op) > 0)));
}

/* Return TRUE for arithmetic operators which can be combined with a multiply
   (shift).  */

int
shiftable_operator (x, mode)
     rtx x;
     enum machine_mode mode;
{
  if (GET_MODE (x) != mode)
    return FALSE;
  else
    {
      enum rtx_code code = GET_CODE (x);

      return (code == PLUS || code == MINUS
	      || code == IOR || code == XOR || code == AND);
    }
}

/* Return TRUE for shift operators. */

int
shift_operator (x, mode)
     rtx x;
     enum machine_mode mode;
{
  if (GET_MODE (x) != mode)
    return FALSE;
  else
    {
      enum rtx_code code = GET_CODE (x);

      if (code == MULT)
	return power_of_two_operand (XEXP (x, 1), mode);

      return (code == ASHIFT || code == ASHIFTRT || code == LSHIFTRT
	      || code == ROTATERT);
    }
}

int equality_operator (x, mode)
     rtx x;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  return GET_CODE (x) == EQ || GET_CODE (x) == NE;
}

/* Return TRUE for SMIN SMAX UMIN UMAX operators. */

int
minmax_operator (x, mode)
     rtx x;
     enum machine_mode mode;
{
  enum rtx_code code = GET_CODE (x);

  if (GET_MODE (x) != mode)
    return FALSE;

  return code == SMIN || code == SMAX || code == UMIN || code == UMAX;
}

/* return TRUE if x is EQ or NE */

/* Return TRUE if this is the condition code register, if we aren't given
   a mode, accept any class CCmode register */

int
cc_register (x, mode)
     rtx x;
     enum machine_mode mode;
{
  if (mode == VOIDmode)
    {
      mode = GET_MODE (x);
      if (GET_MODE_CLASS (mode) != MODE_CC)
	return FALSE;
    }

  if (mode == GET_MODE (x) && GET_CODE (x) == REG && REGNO (x) == 24)
    return TRUE;

  return FALSE;
}

/* Return TRUE if this is the condition code register, if we aren't given
   a mode, accept any class CCmode register which indicates a dominance
   expression.  */

int
dominant_cc_register (x, mode)
     rtx x;
     enum machine_mode mode;
{
  if (mode == VOIDmode)
    {
      mode = GET_MODE (x);
      if (GET_MODE_CLASS (mode) != MODE_CC)
	return