avr.c

俄罗斯高人Mamaich的Pocket gcc编译器（运行在PocketPC上）的全部源代码。

    default:
      abort ();
    }
  return NULL;
}

/* Return the condition name as a string.
   Used in conditional jump constructing  */

static const char *
cond_string (code)
     enum rtx_code code;
{
  switch (code)
    {
    case NE:
      return "ne";
    case EQ:
      return "eq";
    case GE:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
	return "pl";
      else
	return "ge";
    case LT:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
	return "mi";
      else
	return "lt";
    case GEU:
      return "sh";
    case LTU:
      return "lo";
    default:
      abort ();
    }
}

/* Output ADDR to FILE as address */

void
print_operand_address (file, addr)
     FILE *file;
     rtx addr;
{
  switch (GET_CODE (addr))
    {
    case REG:
      fprintf (file, ptrreg_to_str (REGNO (addr)));
      break;

    case PRE_DEC:
      fprintf (file, "-%s", ptrreg_to_str (REGNO (XEXP (addr, 0))));
      break;

    case POST_INC:
      fprintf (file, "%s+", ptrreg_to_str (REGNO (XEXP (addr, 0))));
      break;

    default:
      if (CONSTANT_ADDRESS_P (addr)
	  && ((GET_CODE (addr) == SYMBOL_REF && SYMBOL_REF_FLAG (addr))
	      || GET_CODE (addr) == LABEL_REF))
	{
	  fprintf (file, "pm(");
	  output_addr_const (file,addr);
	  fprintf (file ,")");
	}
      else
	output_addr_const (file, addr);
    }
}


/* Output X as assembler operand to file FILE */
     
void
print_operand (file, x, code)
     FILE *file;
     rtx x;
     int code;
{
  int abcd = 0;

  if (code >= 'A' && code <= 'D')
    abcd = code - 'A';

  if (code == '~')
    {
      if (!AVR_MEGA)
	fputc ('r', file);
    }
  else if (REG_P (x))
    {
      if (x == zero_reg_rtx)
	fprintf (file, "__zero_reg__");
      else
	fprintf (file, reg_names[true_regnum (x) + abcd]);
    }
  else if (GET_CODE (x) == CONST_INT)
    fprintf (file, "%d", INTVAL (x) + abcd);
  else if (GET_CODE (x) == MEM)
    {
      rtx addr = XEXP (x,0);

      if (CONSTANT_P (addr) && abcd)
	{
	  fputc ('(', file);
	  output_address (addr);
	  fprintf (file, ")+%d", abcd);
	}
      else if (code == 'o')
	{
	  if (GET_CODE (addr) != PLUS)
	    fatal_insn ("bad address, not (reg+disp):", addr);

	  print_operand (file, XEXP (addr, 1), 0);
	}
      else if (GET_CODE (addr) == PLUS)
	{
	  print_operand_address (file, XEXP (addr,0));
	  if (REGNO (XEXP (addr, 0)) == REG_X)
	    fatal_insn ("internal compiler error.  Bad address:"
			,addr);
	  fputc ('+', file);
	  print_operand (file, XEXP (addr,1), code);
	}
      else
	print_operand_address (file, addr);
    }
  else if (GET_CODE (x) == CONST_DOUBLE)
    {
      long val;
      REAL_VALUE_TYPE rv;
      if (GET_MODE (x) != SFmode)
	fatal_insn ("internal compiler error.  Unknown mode:", x);
      REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
      REAL_VALUE_TO_TARGET_SINGLE (rv, val);
      fprintf (file, "0x%lx", val);
    }
  else if (code == 'j')
    fputs (cond_string (GET_CODE (x)), file);
  else if (code == 'k')
    fputs (cond_string (reverse_condition (GET_CODE (x))), file);
  else
    print_operand_address (file, x);
}

/* Recognize operand OP of mode MODE used in call instructions */

int
call_insn_operand (op, mode)
     rtx op;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  if (GET_CODE (op) == MEM)
    {
      rtx inside = XEXP (op, 0);
      if (register_operand (inside, Pmode))
        return 1;
      if (CONSTANT_ADDRESS_P (inside))
        return 1;
    }
  return 0;
}

/* Update the condition code in the INSN.  */

void
notice_update_cc (body, insn)
     rtx body ATTRIBUTE_UNUSED;
     rtx insn;
{
  rtx set;
  
  switch (get_attr_cc (insn))
    {
    case CC_NONE:
      /* Insn does not affect CC at all.  */
      break;

    case CC_SET_N:
      CC_STATUS_INIT;
      break;

    case CC_SET_ZN:
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
	{
	  cc_status.flags |= CC_NO_OVERFLOW;
	  cc_status.value1 = SET_DEST (set);
	}
      break;

    case CC_SET_CZN:
      /* Insn sets the Z,N,C flags of CC to recog_operand[0].
         The V flag may or may not be known but that's ok because
         alter_cond will change tests to use EQ/NE.  */
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
	{
	  cc_status.value1 = SET_DEST (set);
	  cc_status.flags |= CC_OVERFLOW_UNUSABLE;
	}
      break;

    case CC_COMPARE:
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
	cc_status.value1 = SET_SRC (set);
      break;
      
    case CC_CLOBBER:
      /* Insn doesn't leave CC in a usable state.  */
      CC_STATUS_INIT;

      /* Correct CC for the ashrqi3 with the shift count as CONST_INT != 6 */
      set = single_set (insn);
      if (set)
	{
	  rtx src = SET_SRC (set);
	  
	  if (GET_CODE (src) == ASHIFTRT
	      && GET_MODE (src) == QImode)
	    {
	      rtx x = XEXP (src, 1);

	      if (GET_CODE (x) == CONST_INT
		  && INTVAL (x) != 6)
		{
		  cc_status.value1 = SET_DEST (set);
		  cc_status.flags |= CC_OVERFLOW_UNUSABLE;
		}
	    }
	}
      break;
    }
}

/* Return maximum number of consecutive registers of
   class CLASS needed to hold a value of mode MODE.  */

int
class_max_nregs (class, mode)
     enum reg_class class ATTRIBUTE_UNUSED;
     enum machine_mode mode;
{
  return ((GET_MODE_SIZE (mode) + UNITS_PER_WORD - 1) / UNITS_PER_WORD);
}

/* Choose mode for jump insn:
   1 - relative jump in range -63 <= x <= 62 ;
   2 - relative jump in range -2046 <= x <= 2045 ;
   3 - absolute jump (only for ATmega[16]03).  */

int
avr_jump_mode (x, insn)
     rtx x;                     /* jump operand */
     rtx insn;                  /* jump insn */
{
  int dest_addr = INSN_ADDRESSES (INSN_UID (GET_MODE (x) == LABEL_REF
					    ? XEXP (x, 0) : x));
  int cur_addr = INSN_ADDRESSES (INSN_UID (insn));
  int jump_distance = cur_addr - dest_addr;
  
  if (-63 <= jump_distance && jump_distance <= 62)
    return 1;
  else if (-2046 <= jump_distance && jump_distance <= 2045)
    return 2;
  else if (AVR_MEGA)
    return 3;
  
  return 2;
}

/* return an AVR condition jump commands.
   X is a comparison RTX.
   LEN is a number returned by avr_jump_mode function.
   if REVERSE nonzero then condition code in X must be reversed.  */

const char *
ret_cond_branch (x, len, reverse)
     rtx x;
     int len;
     int reverse;
{
  RTX_CODE cond = reverse ? reverse_condition (GET_CODE (x)) : GET_CODE (x);
  
  switch (cond)
    {
    case GT:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
	return (len == 1 ? (AS1 (breq,.+2) CR_TAB
			    AS1 (brpl,%0)) :
		len == 2 ? (AS1 (breq,.+4) CR_TAB
			    AS1 (brmi,.+2) CR_TAB
			    AS1 (rjmp,%0)) :
		(AS1 (breq,.+6) CR_TAB
		 AS1 (brmi,.+4) CR_TAB
		 AS1 (jmp,%0)));
	  
      else
	return (len == 1 ? (AS1 (breq,.+2) CR_TAB
			    AS1 (brge,%0)) :
		len == 2 ? (AS1 (breq,.+4) CR_TAB
			    AS1 (brlt,.+2) CR_TAB
			    AS1 (rjmp,%0)) :
		(AS1 (breq,.+6) CR_TAB
		 AS1 (brlt,.+4) CR_TAB
		 AS1 (jmp,%0)));
    case GTU:
      return (len == 1 ? (AS1 (breq,.+2) CR_TAB
                          AS1 (brsh,%0)) :
              len == 2 ? (AS1 (breq,.+4) CR_TAB
                          AS1 (brlo,.+2) CR_TAB
                          AS1 (rjmp,%0)) :
              (AS1 (breq,.+6) CR_TAB
               AS1 (brlo,.+4) CR_TAB
               AS1 (jmp,%0)));
    case LE:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
	return (len == 1 ? (AS1 (breq,%0) CR_TAB
			    AS1 (brmi,%0)) :
		len == 2 ? (AS1 (breq,.+2) CR_TAB
			    AS1 (brpl,.+2) CR_TAB
			    AS1 (rjmp,%0)) :
		(AS1 (breq,.+2) CR_TAB
		 AS1 (brpl,.+4) CR_TAB
		 AS1 (jmp,%0)));
      else
	return (len == 1 ? (AS1 (breq,%0) CR_TAB
			    AS1 (brlt,%0)) :
		len == 2 ? (AS1 (breq,.+2) CR_TAB
			    AS1 (brge,.+2) CR_TAB
			    AS1 (rjmp,%0)) :
		(AS1 (breq,.+2) CR_TAB
		 AS1 (brge,.+4) CR_TAB
		 AS1 (jmp,%0)));
    case LEU:
      return (len == 1 ? (AS1 (breq,%0) CR_TAB
                          AS1 (brlo,%0)) :
              len == 2 ? (AS1 (breq,.+2) CR_TAB
                          AS1 (brsh,.+2) CR_TAB
			  AS1 (rjmp,%0)) :
              (AS1 (breq,.+2) CR_TAB
               AS1 (brsh,.+4) CR_TAB
	       AS1 (jmp,%0)));
    default:
      if (reverse)
	{
	  switch (len)
	    {
	    case 1:
	      return AS1 (br%k1,%0);
	    case 2:
	      return (AS1 (br%j1,.+2) CR_TAB
		      AS1 (rjmp,%0));
	    default:
	      return (AS1 (br%j1,.+4) CR_TAB
		      AS1 (jmp,%0));
	    }
	}
	else
	  {
	    switch (len)
	      {
	      case 1:
		return AS1 (br%j1,%0);
	      case 2:
		return (AS1 (br%k1,.+2) CR_TAB
			AS1 (rjmp,%0));
	      default:
		return (AS1 (br%k1,.+4) CR_TAB
			AS1 (jmp,%0));
	      }
	  }
    }
  return "";
}

/* Predicate function for immediate operand which fits to byte (8bit) */

int
byte_immediate_operand (op, mode)
     register rtx op;
     enum machine_mode mode ATTRIBUTE_UNUSED;
{
  return (GET_CODE (op) == CONST_INT
          && INTVAL (op) <= 0xff && INTVAL (op) >= 0);
}

/* Output all insn addresses and their sizes into the assembly language
   output file.  This is helpful for debugging whether the length attributes
   in the md file are correct.
   Output insn cost for next insn.  */

void
final_prescan_insn (insn, operand, num_operands)
     rtx insn, *operand ATTRIBUTE_UNUSED;
     int num_operands ATTRIBUTE_UNUSED;
{
  int uid = INSN_UID (insn);

  if (TARGET_INSN_SIZE_DUMP || TARGET_ALL_DEBUG)
    {
      fprintf (asm_out_file, "/*DEBUG: 0x%x\t\t%d\t%d */\n",
	       INSN_ADDRESSES (uid),
               INSN_ADDRESSES (uid) - last_insn_address,
	       rtx_cost (PATTERN (insn), INSN));
    }
  last_insn_address = INSN_ADDRESSES (uid);

  if (TARGET_RTL_DUMP)
    {
      fprintf (asm_out_file, "/*****************\n");
      print_rtl_single (asm_out_file, insn);
      fprintf (asm_out_file, "*****************/\n");
    }
}

/* Return 0 if undefined, 1 if always true or always false.  */

int
avr_simplify_comparision_p (mode, operator, x)
     enum machine_mode mode;
     RTX_CODE operator;
     rtx x;
{
  unsigned int max = (mode == QImode ? 0xff :
                      mode == HImode ? 0xffff :
                      mode == SImode ? 0xffffffff : 0);
  if (max && operator && GET_CODE (x) == CONST_INT)
    {
      if (unsigned_condition (operator) != operator)
	max >>= 1;

      if (max != (INTVAL (x) & max)
	  && INTVAL (x) != 0xff)
	return 1;
    }
  return 0;
}


/* Returns nonzero if REGNO is the number of a hard
   register in which function arguments are sometimes passed.  */

int
function_arg_regno_p(r)
     int r;
{
  return (r >= 8 && r <= 25);
}

/* Initializing the variable cum for the state at the beginning
   of the argument list.  */

void
init_cumulative_args (cum, fntype, libname, indirect)
     CUMULATIVE_ARGS *cum;
     tree fntype;
     rtx libname;
     int indirect ATTRIBUTE_UNUSED;
{
  cum->nregs = 18;
  cum->regno = FIRST_CUM_REG;
  if (!libname && fntype)
    {
      int stdarg = (TYPE_ARG_TYPES (fntype) != 0
                    && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype)))
                        != void_type_node));
      if (stdarg)
        cum->nregs = 0;
    }
}

/* Returns the number of registers to allocate for a function argument.  */

static int
avr_num_arg_regs (mode, type)
     enum machine_mode mode;
     tree type;
{
  int size;

  if (mode == BLKmode)
    size = int_size_in_bytes (type);
  else
    size = GET_MODE_SIZE (mode);

  /* Align all function arguments to start in even-numbered registers.
     Odd-sized arguments leave holes above them.  */

  return (size + 1) & ~1;
}

/* Controls whether a function argument is passed
   in a register, and which register. */

rtx
function_arg (cum, mode, type, named)
     CUMULATIVE_ARGS *cum;
     enum machine_mode mode;
     tree type;
     int named ATTRIBUTE_UNUSED;
{
  int bytes = avr_num_arg_regs (mode, type);