arc.c

gcc-2.95.3 Linux下最常用的C编译器

   using call-saved regs as they'll be restored before the delay slot insn.
   Functions with non-empty frames already have enough choices for the epilogue
   delay slot so for now we only consider functions with empty frames.  */

int
arc_delay_slots_for_epilogue ()
{
  if (arc_compute_function_type (current_function_decl) != ARC_FUNCTION_NORMAL)
    return 0;
  if (!current_frame_info.initialized)
    (void) arc_compute_frame_size (get_frame_size ());
  if (current_frame_info.total_size == 0)
    return 1;
  return 0;
}

/* Return true if TRIAL is a valid insn for the epilogue delay slot.
   Any single length instruction which doesn't reference the stack or frame
   pointer or any call-saved register is OK.  SLOT will always be 0.  */

int
arc_eligible_for_epilogue_delay (trial, slot)
     rtx trial;
     int slot;
{
  if (slot != 0)
    abort ();

  if (get_attr_length (trial) == 1
      /* If registers where saved, presumably there's more than enough
	 possibilities for the delay slot.  The alternative is something
	 more complicated (of course, if we expanded the epilogue as rtl
	 this problem would go away).  */
      /* ??? Note that this will always be true since only functions with
	 empty frames have epilogue delay slots.  See
	 arc_delay_slots_for_epilogue.  */
      && current_frame_info.gmask == 0
      && ! reg_mentioned_p (stack_pointer_rtx, PATTERN (trial))
      && ! reg_mentioned_p (frame_pointer_rtx, PATTERN (trial)))
    return 1;
  return 0;
}

/* PIC */

/* Emit special PIC prologues and epilogues.  */

void
arc_finalize_pic ()
{
  /* nothing to do */
}

/* Return true if OP is a shift operator.  */

int
shift_operator (op, mode)
     rtx op;
     enum machine_mode mode;
{
  switch (GET_CODE (op))
    {
    case ASHIFTRT:
    case LSHIFTRT:
    case ASHIFT:
      return 1;
    default:
      return 0;
    }
}

/* Output the assembler code for doing a shift.
   We go to a bit of trouble to generate efficient code as the ARC only has
   single bit shifts.  This is taken from the h8300 port.  We only have one
   mode of shifting and can't access individual bytes like the h8300 can, so
   this is greatly simplified (at the expense of not generating hyper-
   efficient code).

   This function is not used if the variable shift insns are present.  */

/* ??? We assume the output operand is the same as operand 1.
   This can be optimized (deleted) in the case of 1 bit shifts.  */
/* ??? We use the loop register here.  We don't use it elsewhere (yet) and
   using it here will give us a chance to play with it.  */

char *
output_shift (operands)
     rtx *operands;
{
  static int loopend_lab;
  rtx shift = operands[3];
  enum machine_mode mode = GET_MODE (shift);
  enum rtx_code code = GET_CODE (shift);
  char *shift_one;

  if (mode != SImode)
    abort ();

  switch (code)
    {
    case ASHIFT:   shift_one = "asl %0,%0"; break;
    case ASHIFTRT: shift_one = "asr %0,%0"; break;
    case LSHIFTRT: shift_one = "lsr %0,%0"; break;
    default:       abort ();
    }

  if (GET_CODE (operands[2]) != CONST_INT)
    {
      if (optimize)
	output_asm_insn ("mov lp_count,%2", operands);
      else
	output_asm_insn ("mov %4,%2", operands);
      goto shiftloop;
    }
  else
    {
      int n = INTVAL (operands[2]);

      /* If the count is negative, make it 0.  */
      if (n < 0)
	n = 0;
      /* If the count is too big, truncate it.
         ANSI says shifts of GET_MODE_BITSIZE are undefined - we choose to
	 do the intuitive thing.  */
      else if (n > GET_MODE_BITSIZE (mode))
	n = GET_MODE_BITSIZE (mode);

      /* First see if we can do them inline.  */
      if (n <= 8)
	{
	  while (--n >= 0)
	    output_asm_insn (shift_one, operands);
	}
      /* See if we can use a rotate/and.  */
      else if (n == BITS_PER_WORD - 1)
	{
	  switch (code)
	    {
	    case ASHIFT :
	      output_asm_insn ("and %0,%0,1\n\tror %0,%0", operands);
	      break;
	    case ASHIFTRT :
	      /* The ARC doesn't have a rol insn.  Use something else.  */
	      output_asm_insn ("asl.f 0,%0\n\tsbc %0,0,0", operands);
	      break;
	    case LSHIFTRT :
	      /* The ARC doesn't have a rol insn.  Use something else.  */
	      output_asm_insn ("asl.f 0,%0\n\tadc %0,0,0", operands);
	      break;
	    }
	}
      /* Must loop.  */
      else
	{
	  char buf[100];

	  if (optimize)
	    output_asm_insn ("mov lp_count,%c2", operands);
	  else
	    output_asm_insn ("mov %4,%c2", operands);
	shiftloop:
	  if (optimize)
	    {
	      if (flag_pic)
		sprintf ("lr %%4,[status]\n\tadd %%4,%%4,6\t%s single insn loop start",
			 ASM_COMMENT_START);
	      else
		sprintf (buf, "mov %%4,%%%%st(1f)\t%s (single insn loop start) >> 2",
			 ASM_COMMENT_START);
	      output_asm_insn (buf, operands);
	      output_asm_insn ("sr %4,[lp_start]", operands);
	      output_asm_insn ("add %4,%4,1", operands);
	      output_asm_insn ("sr %4,[lp_end]", operands);
	      output_asm_insn ("nop\n\tnop", operands);
	      if (flag_pic)
		asm_fprintf (asm_out_file, "\t%s single insn loop\n",
			     ASM_COMMENT_START);
	      else
		asm_fprintf (asm_out_file, "1:\t%s single insn loop\n",
			     ASM_COMMENT_START);
	      output_asm_insn (shift_one, operands);
	    }
	  else 
	    {
	      asm_fprintf (asm_out_file, "1:\t%s begin shift loop\n",
			   ASM_COMMENT_START);
	      output_asm_insn ("sub.f %4,%4,1", operands);
	      output_asm_insn ("nop", operands);
	      output_asm_insn ("bn.nd 2f", operands);
	      output_asm_insn (shift_one, operands);
	      output_asm_insn ("b.nd 1b", operands);
	      asm_fprintf (asm_out_file, "2:\t%s end shift loop\n",
			   ASM_COMMENT_START);
	    }
	}
    }

  return "";
}

/* Nested function support.  */

/* Emit RTL insns to initialize the variable parts of a trampoline.
   FNADDR is an RTX for the address of the function's pure code.
   CXT is an RTX for the static chain value for the function.  */

void
arc_initialize_trampoline (tramp, fnaddr, cxt)
     rtx tramp, fnaddr, cxt;
{
}

/* Set the cpu type and print out other fancy things,
   at the top of the file.  */

void
arc_asm_file_start (file)
     FILE *file;
{
  fprintf (file, "\t.cpu %s\n", arc_cpu_string);
}

/* Print operand X (an rtx) in assembler syntax to file FILE.
   CODE is a letter or dot (`z' in `%z0') or 0 if no letter was specified.
   For `%' followed by punctuation, CODE is the punctuation and X is null.  */

void
arc_print_operand (file, x, code)
     FILE *file;
     rtx x;
     int code;
{
  switch (code)
    {
    case '#' :
      /* Conditional branches.  For now these are equivalent.  */
    case '*' :
      /* Unconditional branches.  Output the appropriate delay slot suffix.  */
      if (!final_sequence || XVECLEN (final_sequence, 0) == 1)
	{
	  /* There's nothing in the delay slot.  */
	  fputs (".nd", file);
	}
      else
	{
	  rtx jump = XVECEXP (final_sequence, 0, 0);
	  rtx delay = XVECEXP (final_sequence, 0, 1);
	  if (INSN_ANNULLED_BRANCH_P (jump))
	    fputs (INSN_FROM_TARGET_P (delay) ? ".jd" : ".nd", file);
	  else
	    fputs (".d", file);
	}
      return;
    case '?' : /* with leading "." */
    case '!' : /* without leading "." */
      /* This insn can be conditionally executed.  See if the ccfsm machinery
	 says it should be conditionalized.  */
      if (arc_ccfsm_state == 3 || arc_ccfsm_state == 4)
	{
	  /* Is this insn in a delay slot?  */
	  if (final_sequence && XVECLEN (final_sequence, 0) == 2)
	    {
	      rtx insn = XVECEXP (final_sequence, 0, 1);

	      /* If the insn is annulled and is from the target path, we need
		 to inverse the condition test.  */
	      if (INSN_ANNULLED_BRANCH_P (insn))
		{
		  if (INSN_FROM_TARGET_P (insn))
		    fprintf (file, "%s%s",
			     code == '?' ? "." : "",
			     arc_condition_codes[ARC_INVERSE_CONDITION_CODE (arc_ccfsm_current_cc)]);
		  else
		    fprintf (file, "%s%s",
			     code == '?' ? "." : "",
			     arc_condition_codes[arc_ccfsm_current_cc]);
		}
	      else
		/* This insn is executed for either path, so don't
		   conditionalize it at all.  */
		; /* nothing to do */
	    }
	  else
	    {
	      /* This insn isn't in a delay slot.  */
	      fprintf (file, "%s%s",
		       code == '?' ? "." : "",
		       arc_condition_codes[arc_ccfsm_current_cc]);
	    }
	}
      return;
    case '~' :
      /* Output a nop if we're between a set of the condition codes,
	 and a conditional branch.  */
      if (last_insn_set_cc_p)
	fputs ("nop\n\t", file);
      return;
    case 'd' :
      fputs (arc_condition_codes[get_arc_condition_code (x)], file);
      return;
    case 'D' :
      fputs (arc_condition_codes[ARC_INVERSE_CONDITION_CODE
				 (get_arc_condition_code (x))],
	     file);
      return;
    case 'R' :
      /* Write second word of DImode or DFmode reference,
	 register or memory.  */
      if (GET_CODE (x) == REG)
	fputs (reg_names[REGNO (x)+1], file);
      else if (GET_CODE (x) == MEM)
	{
	  fputc ('[', file);
	  /* Handle possible auto-increment.  Since it is pre-increment and
	     we have already done it, we can just use an offset of four.  */
	  /* ??? This is taken from rs6000.c I think.  I don't think it is
	     currently necessary, but keep it around.  */
	  if (GET_CODE (XEXP (x, 0)) == PRE_INC
	      || GET_CODE (XEXP (x, 0)) == PRE_DEC)
	    output_address (plus_constant (XEXP (XEXP (x, 0), 0), 4));
	  else
	    output_address (plus_constant (XEXP (x, 0), 4));
	  fputc (']', file);
	}
      else
	output_operand_lossage ("invalid operand to %R code");
      return;
    case 'S' :
      if ((GET_CODE (x) == SYMBOL_REF && SYMBOL_REF_FLAG (x))
	  || GET_CODE (x) == LABEL_REF)
	{
	  fprintf (file, "%%st(");
	  output_addr_const (file, x);
	  fprintf (file, ")");
	  return;
	}
      break;
    case 'H' :
    case 'L' :
      if (GET_CODE (x) == REG)
	{
	  /* L = least significant word, H = most significant word */
	  if ((TARGET_BIG_ENDIAN != 0) ^ (code == 'L'))
	    fputs (reg_names[REGNO (x)], file);
	  else
	    fputs (reg_names[REGNO (x)+1], file);
	}
      else if (GET_CODE (x) == CONST_INT
	       || GET_CODE (x) == CONST_DOUBLE)
	{
	  rtx first, second;

	  split_double (x, &first, &second);
	  fprintf (file, "0x%08lx",
		   code == 'L' ? INTVAL (first) : INTVAL (second));
	}
      else
	output_operand_lossage ("invalid operand to %H/%L code");
      return;
    case 'A' :
      {
	REAL_VALUE_TYPE d;
	char str[30];

	if (GET_CODE (x) != CONST_DOUBLE
	    || GET_MODE_CLASS (GET_MODE (x)) != MODE_FLOAT)
	  abort ();
	REAL_VALUE_FROM_CONST_DOUBLE (d, x);
	REAL_VALUE_TO_DECIMAL (d, "%.20e", str);
	fprintf (file, "%s", str);
	return;
      }
    case 'U' :
      /* Output a load/store with update indicator if appropriate.  */
      if (GET_CODE (x) == MEM)
	{
	  if (GET_CODE (XEXP (x, 0)) == PRE_INC
	      || GET_CODE (XEXP (x, 0)) == PRE_DEC)
	    fputs (".a", file);
	}
      else
	output_operand_lossage ("invalid operand to %U code");
      return;
    case 'V' :
      /* Output cache bypass indicator for a load/store insn.  Volatile memory
	 refs are defined to use the cache bypass mechanism.  */
      if (GET_CODE (x) == MEM)
	{
	  if (MEM_VOLATILE_P (x))
	    fputs (".di", file);
	}
      else
	output_operand_lossage ("invalid operand to %V code");
      return;
    case 0 :
      /* Do nothing special.  */
      break;
    default :
      /* Unknown flag.  */
      output_operand_lossage ("invalid operand output code");
    }

  switch (GET_CODE (x))
    {
    case REG :
      fputs (reg_names[REGNO (x)], file);
      break;
    case MEM :
      fputc ('[', file);
      if (GET_CODE (XEXP (x, 0)) == PRE_INC)
	output_address (plus_constant (XEXP (XEXP (x, 0), 0),
				       GET_MODE_SIZE (GET_MODE (x))));
      else if (GET_CODE (XEXP (x, 0)) == PRE_DEC)
	output_address (plus_constant (XEXP (XEXP (x, 0), 0),
				       - GET_MODE_SIZE (GET_MODE (x))));
      else
	output_address (XEXP (x, 0));
      fputc (']', file);
      break;
    case CONST_DOUBLE :
      /* We handle SFmode constants here as output_addr_const doesn't.  */
      if (GET_MODE (x) == SFmode)
	{
	  REAL_VALUE_TYPE d;
	  long l;

	  REAL_VALUE_FROM_CONST_DOUBLE (d, x);
	  REAL_VALUE_TO_TARGET_SINGLE (d, l);
	  fprintf (file, "0x%08lx", l);
	  break;
	}
      /* Fall through.  Let output_addr_const deal with it.  */
    default :
      output_addr_const (file, x);
      break;
    }
}

/* Print a memory address as an operand to reference that memory location.  */

void