rs6000.c

早期freebsd实现

	fprintf (file, "u");
      return;

    case 'I':
      /* Print `i' is this is a constant, else nothing.  */
      if (INT_P (x))
	fprintf (file, "i");
      return;

    case 'N':
      /* Write the number of elements in the vector times 4.  */
      if (GET_CODE (x) != PARALLEL)
	output_operand_lossage ("invalid %%N value");

      fprintf (file, "%d", XVECLEN (x, 0) * 4);
      return;

    case 'O':
      /* Similar, but subtract 1 first.  */
      if (GET_CODE (x) != PARALLEL)
	output_operand_lossage ("invalid %%N value");

      fprintf (file, "%d", (XVECLEN (x, 0) - 1) * 4);
      return;

    case 'P':
      /* The operand must be an indirect memory reference.  The result
	 is the register number. */
      if (GET_CODE (x) != MEM || GET_CODE (XEXP (x, 0)) != REG
	  || REGNO (XEXP (x, 0)) >= 32)
	output_operand_lossage ("invalid %%P value");

      fprintf (file, "%d", REGNO (XEXP (x, 0)));
      return;

    case 'L':
      /* Write second word of DImode or DFmode reference.  Works on register
	 or non-indexed memory only.  */
      if (GET_CODE (x) == REG)
	fprintf (file, "%d", REGNO (x) + 1);
      else if (GET_CODE (x) == MEM)
	{
	  /* Handle possible auto-increment.  Since it is pre-increment and
	     we have already done it, we can just use an offset of four.  */
	  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));
	}
      return;
			    
    case 'Y':
      /* Similar, for third word of TImode  */
      if (GET_CODE (x) == REG)
	fprintf (file, "%d", REGNO (x) + 2);
      else if (GET_CODE (x) == MEM)
	{
	  if (GET_CODE (XEXP (x, 0)) == PRE_INC
	      || GET_CODE (XEXP (x, 0)) == PRE_DEC)
	    output_address (plus_constant (XEXP (XEXP (x, 0), 0), 8));
	  else
	    output_address (plus_constant (XEXP (x, 0), 8));
	}
      return;
			    
    case 'Z':
      /* Similar, for last word of TImode.  */
      if (GET_CODE (x) == REG)
	fprintf (file, "%d", REGNO (x) + 3);
      else if (GET_CODE (x) == MEM)
	{
	  if (GET_CODE (XEXP (x, 0)) == PRE_INC
	      || GET_CODE (XEXP (x, 0)) == PRE_DEC)
	    output_address (plus_constant (XEXP (XEXP (x, 0), 0), 12));
	  else
	    output_address (plus_constant (XEXP (x, 0), 12));
	}
      return;
			    
    case 't':
      /* Write 12 if this jump operation will branch if true, 4 otherwise. 
	 All floating-point operations except NE branch true and integer
	 EQ, LT, GT, LTU and GTU also branch true.  */
      if (GET_RTX_CLASS (GET_CODE (x)) != '<')
	output_operand_lossage ("invalid %%t value");

      else if ((GET_MODE (XEXP (x, 0)) == CCFPmode
		&& GET_CODE (x) != NE)
	       || GET_CODE (x) == EQ
	       || GET_CODE (x) == LT || GET_CODE (x) == GT
	       || GET_CODE (x) == LTU || GET_CODE (x) == GTU)
	fprintf (file, "12");
      else
	fprintf (file, "4");
      return;
      
    case 'T':
      /* Opposite of 't': write 4 if this jump operation will branch if true,
	 12 otherwise.   */
      if (GET_RTX_CLASS (GET_CODE (x)) != '<')
	output_operand_lossage ("invalid %%t value");

      else if ((GET_MODE (XEXP (x, 0)) == CCFPmode
		&& GET_CODE (x) != NE)
	       || GET_CODE (x) == EQ
	       || GET_CODE (x) == LT || GET_CODE (x) == GT
	       || GET_CODE (x) == LTU || GET_CODE (x) == GTU)
	fprintf (file, "4");
      else
	fprintf (file, "12");
      return;
      
    case 'j':
      /* Write the bit number in CCR for jump.  */
      i = ccr_bit (x, 0);
      if (i == -1)
	output_operand_lossage ("invalid %%j code");
      else
	fprintf (file, "%d", i);
      return;

    case 'J':
      /* Similar, but add one for shift count in rlinm for scc and pass
	 scc flag to `ccr_bit'.  */
      i = ccr_bit (x, 1);
      if (i == -1)
	output_operand_lossage ("invalid %%J code");
      else
	fprintf (file, "%d", i + 1);
      return;

    case 'C':
      /* This is an optional cror needed for LE or GE floating-point
	 comparisons.  Otherwise write nothing.  */
      if ((GET_CODE (x) == LE || GET_CODE (x) == GE)
	  && GET_MODE (XEXP (x, 0)) == CCFPmode)
	{
	  int base_bit = 4 * (REGNO (XEXP (x, 0)) - 68);

	  fprintf (file, "cror %d,%d,%d\n\t", base_bit + 3,
		   base_bit + 2, base_bit + (GET_CODE (x) == GE));
	}
      return;

    case 'D':
      /* Similar, except that this is for an scc, so we must be able to
	 encode the test in a single bit that is one.  We do the above
	 for any LE, GE, GEU, or LEU and invert the bit for NE.  */
      if (GET_CODE (x) == LE || GET_CODE (x) == GE
	  || GET_CODE (x) == LEU || GET_CODE (x) == GEU)
	{
	  int base_bit = 4 * (REGNO (XEXP (x, 0)) - 68);

	  fprintf (file, "cror %d,%d,%d\n\t", base_bit + 3,
		   base_bit + 2,
		   base_bit + (GET_CODE (x) == GE || GET_CODE (x) == GEU));
	}

      else if (GET_CODE (x) == NE)
	{
	  int base_bit = 4 * (REGNO (XEXP (x, 0)) - 68);

	  fprintf (file, "crnor %d,%d,%d\n\t", base_bit + 3,
		   base_bit + 2, base_bit + 2);
	}
      return;

    case 'z':
      /* X is a SYMBOL_REF.  Write out the name preceded by a
	 period and without any trailing data in brackets.  Used for function
	 names.  */
      if (GET_CODE (x) != SYMBOL_REF)
	abort ();

      fprintf (file, ".");
      RS6000_OUTPUT_BASENAME (file, XSTR (x, 0));
      return;

    case 'A':
      /* If X is a constant integer whose low-order 5 bits are zero,
	 write 'l'.  Otherwise, write 'r'.  This is a kludge to fix a bug
	 in the RS/6000 assembler where "sri" with a zero shift count
	 write a trash instruction.  */
      if (GET_CODE (x) == CONST_INT && (INTVAL (x) & 31) == 0)
	fprintf (file, "l");
      else
	fprintf (file, "r");
      return;

    case 0:
      if (GET_CODE (x) == REG)
	fprintf (file, "%s", reg_names[REGNO (x)]);
      else if (GET_CODE (x) == MEM)
	{
	  /* We need to handle PRE_INC and PRE_DEC here, since we need to
	     know the width from the mode.  */
	  if (GET_CODE (XEXP (x, 0)) == PRE_INC)
	    fprintf (file, "%d(%d)", GET_MODE_SIZE (GET_MODE (x)),
		     REGNO (XEXP (XEXP (x, 0), 0)));
	  else if (GET_CODE (XEXP (x, 0)) == PRE_DEC)
	    fprintf (file, "%d(%d)", - GET_MODE_SIZE (GET_MODE (x)),
		     REGNO (XEXP (XEXP (x, 0), 0)));
	  else
	    output_address (XEXP (x, 0));
	}
      else
	output_addr_const (file, x);
      break;

    default:
      output_operand_lossage ("invalid %%xn code");
    }
}

/* Print the address of an operand.  */

void
print_operand_address (file, x)
     FILE *file;
     register rtx x;
{
  if (GET_CODE (x) == REG)
    fprintf (file, "0(%d)", REGNO (x));
  else if (GET_CODE (x) == SYMBOL_REF || GET_CODE (x) == CONST)
    {
      output_addr_const (file, x);
      fprintf (file, "(2)");
    }
  else if (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == REG)
    {
      if (REGNO (XEXP (x, 0)) == 0)
	fprintf (file, "%d,%d", REGNO (XEXP (x, 1)), REGNO (XEXP (x, 0)));
      else
	fprintf (file, "%d,%d", REGNO (XEXP (x, 0)), REGNO (XEXP (x, 1)));
    }
  else if (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT)
    fprintf (file, "%d(%d)", INTVAL (XEXP (x, 1)), REGNO (XEXP (x, 0)));
  else
    abort ();
}

/* This page contains routines that are used to determine what the function
   prologue and epilogue code will do and write them out.  */

/*  Return the first fixed-point register that is required to be saved. 32 if
    none.  */

int
first_reg_to_save ()
{
  int first_reg;

  /* Find lowest numbered live register.  */
  for (first_reg = 13; first_reg <= 31; first_reg++)
    if (regs_ever_live[first_reg])
      break;

  /* If profiling, then we must save/restore every register that contains
     a parameter before/after the .mcount call.  Use registers from 30 down
     to 23 to do this.  Don't use the frame pointer in reg 31.

     For now, save enough room for all of the parameter registers.  */
  if (profile_flag)
    if (first_reg > 23)
      first_reg = 23;

  return first_reg;
}

/* Similar, for FP regs.  */

int
first_fp_reg_to_save ()
{
  int first_reg;

  /* Find lowest numbered live register.  */
  for (first_reg = 14 + 32; first_reg <= 63; first_reg++)
    if (regs_ever_live[first_reg])
      break;

  return first_reg;
}

/* Return 1 if we need to save CR.  */

int
must_save_cr ()
{
  return regs_ever_live[70] || regs_ever_live[71] || regs_ever_live[72];
}

/* Compute the size of the save area in the stack, including the space for
   the fixed area.  */

int
rs6000_sa_size ()
{
  int size;
  int i;

  /* We have the six fixed words, plus the size of the register save 
     areas, rounded to a double-word.  */
  size = 6 + (32 - first_reg_to_save ()) + (64 - first_fp_reg_to_save ()) * 2;
  if (size & 1)
    size++;

  return size * 4;
}

/* Return non-zero if this function makes calls.  */

int
rs6000_makes_calls ()
{
  rtx insn;

  for (insn = get_insns (); insn; insn = next_insn (insn))
    if (GET_CODE (insn) == CALL_INSN)
      return 1;

  return 0;
}

/* Return non-zero if this function needs to push space on the stack.  */

int
rs6000_pushes_stack ()
{
  int total_size = (rs6000_sa_size () + get_frame_size ()
		    + current_function_outgoing_args_size);

  /* We need to push the stack if a frame pointer is needed (because the
     stack might be dynamically adjusted), if we are debugging, if the
     total stack size is more than 220 bytes, or if we make calls.  */

  return (frame_pointer_needed || write_symbols != NO_DEBUG
	  || total_size > 220
	  || rs6000_makes_calls ());
}

/* Write function prologue.  */

void
output_prolog (file, size)
     FILE *file;
     int size;
{
  int first_reg = first_reg_to_save ();
  int must_push = rs6000_pushes_stack ();
  int first_fp_reg = first_fp_reg_to_save ();
  int basic_size = rs6000_sa_size ();
  int total_size = (basic_size + size + current_function_outgoing_args_size);

  /* Round size to multiple of 8 bytes.  */
  total_size = (total_size + 7) & ~7;

  /* Write .extern for any function we will call to save and restore fp
     values.  */
  if (first_fp_reg < 62)
    fprintf (file, "\t.extern ._savef%d\n\t.extern ._restf%d\n",
	     first_fp_reg - 32, first_fp_reg - 32);

  /* Write .extern for truncation routines, if needed.  */
  if (rs6000_trunc_used && ! trunc_defined)
    {
      fprintf (file, "\t.extern .itrunc\n\t.extern .uitrunc\n");
      trunc_defined = 1;
    }

  /* If we have to call a function to save fpr's, or if we are doing profiling,
     then we will be using LR.  */
  if (first_fp_reg < 62 || profile_flag)
    regs_ever_live[65] = 1;

  /* If we use the link register, get it into r0.  */
  if (regs_ever_live[65])
    fprintf (file, "\tmflr 0\n");

  /* If we need to save CR, put it into r12.  */
  if (must_save_cr ())
    fprintf (file, "\tmfcr 12\n");

  /* Do any required saving of fpr's.  If only one or two to save, do it
     ourself.  Otherwise, call function.  */
  if (first_fp_reg == 62)
    fprintf (file, "\tstfd 30,-16(1)\n\tstfd 31,-8(1)\n");
  else if (first_fp_reg == 63)
    fprintf (file, "\tstfd 31,-8(1)\n");
  else if (first_fp_reg != 64)
    fprintf (file, "\tbl ._savef%d\n\tcror 15,15,15\n", first_fp_reg - 32);

  /* Now save gpr's.  */
  if (first_reg == 31)
    fprintf (file, "\tst 31,%d(1)\n", -4 - (64 - first_fp_reg) * 8);
  else if (first_reg != 32)
    fprintf (file, "\tstm %d,%d(1)\n", first_reg,
	     - (32 - first_reg) * 4 - (64 - first_fp_reg) * 8);

  /* Save lr if we used it.  */
  if (regs_ever_live[65])
    fprintf (file, "\tst 0,8(1)\n");

  /* Save CR if we use any that must be preserved.  */
  if (must_save_cr ())
    fprintf (file, "\tst 12,4(1)\n");

  /* Update stack and set back pointer.  */
  if (must_push)
    {
      if (total_size < 32767)
	fprintf (file, "\tstu 1,%d(1)\n", - total_size);
      else
	{
	  fprintf (file, "\tcau 0,0,%d\n\toril 0,0,%d\n",
		   (total_size >> 16) & 0xffff, total_size & 0xffff);
	  fprintf (file, "\tsf 12,0,1\n\tst 1,0(12)\n\toril 1,12,0\n");
	}
    }

  /* Set frame pointer, if needed.  */
  if (frame_pointer_needed)
    fprintf (file, "\toril 31,1,0\n");
}

/* Write function epilogue.  */

void
output_epilog (file, size)
     FILE *file;
     int size;
{
  int first_reg = first_reg_to_save ();
  int must_push = rs6000_pushes_stack ();
  int first_fp_reg = first_fp_reg_to_save ();
  int basic_size = rs6000_sa_size ();
  int total_size = (basic_size + size + current_function_outgoing_args_size);
  rtx insn = get_last_insn ();

  /* Round size to multiple of 8 bytes.  */
  total_size = (total_size + 7) & ~7;

  /* If the last insn was a BARRIER, we don't have to write anything except
     the trace table.  */
  if (GET_CODE (insn) == NOTE)
    insn = prev_nonnote_insn (insn);
  if (insn == 0 ||  GET_CODE (insn) != BARRIER)
    {
      /* If we have a frame pointer, a call to alloca,  or a large stack
	 frame, restore the old stack pointer using the backchain.  Otherwise,
	 we know what size to update it with.  */