i960.c

GUN开源阻止下的编译器GCC

  if (GET_CODE (x) == PLUS)
    {
      rtx base = XEXP (x, 0);
      rtx offset = XEXP (x, 1);

      if (GET_CODE (base) == SUBREG)
	base = SUBREG_REG (base);
      if (GET_CODE (offset) == SUBREG)
	offset = SUBREG_REG (offset);

      if (GET_CODE (base) == REG)
	{
	  if (GET_CODE (offset) == REG)
	    return 2;
	  if (GET_CODE (offset) == CONST_INT)
	    {
	      if ((unsigned)INTVAL (offset) < 2047)
		return 2;
	      return 4;
	    }
	  if (CONSTANT_P (offset))
	    return 4;
	}
      if (GET_CODE (base) == PLUS || GET_CODE (base) == MULT)
	return 6;

      /* This is an invalid address.  The return value doesn't matter, but
	 for convenience we make this more expensive than anything else.  */
      return 12;
    }
  if (GET_CODE (x) == MULT)
    return 6;

  /* Symbol_refs and other unrecognized addresses are cost 4.  */
  return 4;
}

/* Emit insns to move operands[1] into operands[0].

   Return 1 if we have written out everything that needs to be done to
   do the move.  Otherwise, return 0 and the caller will emit the move
   normally.  */

int
emit_move_sequence (operands, mode)
     rtx *operands;
     enum machine_mode mode;
{
  /* We can only store registers to memory.  */

  if (GET_CODE (operands[0]) == MEM && GET_CODE (operands[1]) != REG)
    operands[1] = force_reg (mode, operands[1]);

  /* Storing multi-word values in unaligned hard registers to memory may
     require a scratch since we have to store them a register at a time and
     adding 4 to the memory address may not yield a valid insn.  */
  /* ??? We don't always need the scratch, but that would complicate things.
     Maybe later.  */
  if (GET_MODE_SIZE (mode) > UNITS_PER_WORD
      && GET_CODE (operands[0]) == MEM
      && GET_CODE (operands[1]) == REG
      && REGNO (operands[1]) < FIRST_PSEUDO_REGISTER
      && ! HARD_REGNO_MODE_OK (REGNO (operands[1]), mode))
    {
      emit_insn (gen_rtx (PARALLEL, VOIDmode,
			  gen_rtvec (2,
				     gen_rtx (SET, VOIDmode,
					      operands[0], operands[1]),
				     gen_rtx (CLOBBER, VOIDmode,
					      gen_rtx (SCRATCH, Pmode)))));
      return 1;
    }

  return 0;
}

/* Output assembler to move a double word value.  */

char *
i960_output_move_double (dst, src)
     rtx dst, src;
{
  rtx operands[5];

  if (GET_CODE (dst) == REG
      && GET_CODE (src) == REG)
    {
      if ((REGNO (src) & 1)
	  || (REGNO (dst) & 1))
	{
	  /* We normally copy the low-numbered register first.  However, if
	     the second source register is the same as the first destination
	     register, we must copy in the opposite order.  */
	  if (REGNO (src) + 1 == REGNO (dst))
	    return "mov	%D1,%D0\n\tmov	%1,%0";
	  else
	    return "mov	%1,%0\n\tmov	%D1,%D0";
	}
      else
	return "movl	%1,%0";
    }
  else if (GET_CODE (dst) == REG
	   && GET_CODE (src) == CONST_INT
	   && CONST_OK_FOR_LETTER_P (INTVAL (src), 'I'))
    {
      if (REGNO (dst) & 1)
	return "mov	%1,%0\n\tmov	0,%D0";
      else
	return "movl	%1,%0";
    }
  else if (GET_CODE (dst) == REG
	   && GET_CODE (src) == MEM)
    {
      if (REGNO (dst) & 1)
	{
	  /* One can optimize a few cases here, but you have to be
	     careful of clobbering registers used in the address and
	     edge conditions.  */
	  operands[0] = dst;
	  operands[1] = src;
	  operands[2] = gen_rtx (REG, Pmode, REGNO (dst) + 1);
	  operands[3] = gen_rtx (MEM, word_mode, operands[2]);
	  operands[4] = adj_offsettable_operand (operands[3], UNITS_PER_WORD);
	  output_asm_insn ("lda	%1,%2\n\tld	%3,%0\n\tld	%4,%D0", operands);
	  return "";
	}
      else
	return "ldl	%1,%0";
    }
  else if (GET_CODE (dst) == MEM
	   && GET_CODE (src) == REG)
    {
      if (REGNO (src) & 1)
	{
	  /* This is handled by emit_move_sequence so we shouldn't get here.  */
	  abort ();
	}
      return "stl	%1,%0";
    }
  else
    abort ();
}

/* Output assembler to move a quad word value.  */

char *
i960_output_move_quad (dst, src)
     rtx dst, src;
{
  rtx operands[7];

  if (GET_CODE (dst) == REG
      && GET_CODE (src) == REG)
    {
      if ((REGNO (src) & 3)
	  || (REGNO (dst) & 3))
	{
	  /* We normally copy starting with the low numbered register.
	     However, if there is an overlap such that the first dest reg
	     is <= the last source reg but not < the first source reg, we
	     must copy in the opposite order.  */
	  if (REGNO (dst) <= REGNO (src) + 3
	      && REGNO (dst) >= REGNO (src))
	    return "mov	%F1,%F0\n\tmov	%E1,%E0\n\tmov	%D1,%D0\n\tmov	%1,%0";
	  else
	    return "mov	%1,%0\n\tmov	%D1,%D0\n\tmov	%E1,%E0\n\tmov	%F1,%F0";
	}
      else
	return "movq	%1,%0";
    }
  else if (GET_CODE (dst) == REG
	   && GET_CODE (src) == CONST_INT
	   && CONST_OK_FOR_LETTER_P (INTVAL (src), 'I'))
    {
      if (REGNO (dst) & 3)
	return "mov	%1,%0\n\tmov	0,%D0\n\tmov	0,%E0\n\tmov	0,%F0";
      else
	return "movq	%1,%0";
    }
  else if (GET_CODE (dst) == REG
	   && GET_CODE (src) == MEM)
    {
      if (REGNO (dst) & 3)
	{
	  /* One can optimize a few cases here, but you have to be
	     careful of clobbering registers used in the address and
	     edge conditions.  */
	  operands[0] = dst;
	  operands[1] = src;
	  operands[2] = gen_rtx (REG, Pmode, REGNO (dst) + 3);
	  operands[3] = gen_rtx (MEM, word_mode, operands[2]);
	  operands[4] = adj_offsettable_operand (operands[3], UNITS_PER_WORD);
	  operands[5] = adj_offsettable_operand (operands[4], UNITS_PER_WORD);
	  operands[6] = adj_offsettable_operand (operands[5], UNITS_PER_WORD);
	  output_asm_insn ("lda	%1,%2\n\tld	%3,%0\n\tld	%4,%D0\n\tld	%5,%E0\n\tld	%6,%F0", operands);
	  return "";
	}
      else
	return "ldq	%1,%0";
    }
  else if (GET_CODE (dst) == MEM
	   && GET_CODE (src) == REG)
    {
      if (REGNO (src) & 3)
	{
	  /* This is handled by emit_move_sequence so we shouldn't get here.  */
	  abort ();
	}
      return "stq	%1,%0";
    }
  else
    abort ();
}

/* Emit insns to load a constant to non-floating point registers.
   Uses several strategies to try to use as few insns as possible.  */

char *
i960_output_ldconst (dst, src)
     register rtx dst, src;
{
  register int rsrc1;
  register unsigned rsrc2;
  enum machine_mode mode = GET_MODE (dst);
  rtx operands[4];

  operands[0] = operands[2] = dst;
  operands[1] = operands[3] = src;

  /* Anything that isn't a compile time constant, such as a SYMBOL_REF,
     must be a ldconst insn.  */

  if (GET_CODE (src) != CONST_INT && GET_CODE (src) != CONST_DOUBLE)
    {
      output_asm_insn ("ldconst	%1,%0", operands);
      return "";
    }
  else if (mode == XFmode)
    {
      REAL_VALUE_TYPE d;
      long value_long[3];
      int i;

      if (fp_literal_zero (src, XFmode))
	return "movt	0,%0";

      REAL_VALUE_FROM_CONST_DOUBLE (d, src);
      REAL_VALUE_TO_TARGET_LONG_DOUBLE (d, value_long);

      output_asm_insn ("# ldconst	%1,%0",operands);

      for (i = 0; i < 3; i++)
	{
	  operands[0] = gen_rtx (REG, SImode, REGNO (dst) + i);
	  operands[1] = GEN_INT (value_long[i]);
	  output_asm_insn (i960_output_ldconst (operands[0], operands[1]),
			   operands);
	}

      return ""; 
   }
  else if (mode == DFmode)
    {
      rtx first, second;

      if (fp_literal_zero (src, DFmode))
	return "movl	0,%0";

      split_double (src, &first, &second);

      output_asm_insn ("# ldconst	%1,%0",operands);

      operands[0] = gen_rtx (REG, SImode, REGNO (dst));
      operands[1] = first;
      output_asm_insn (i960_output_ldconst (operands[0], operands[1]),
		      operands);
      operands[0] = gen_rtx (REG, SImode, REGNO (dst) + 1);
      operands[1] = second;
      output_asm_insn (i960_output_ldconst (operands[0], operands[1]),
		      operands);
      return "";
    }
  else if (mode == SFmode)
    {
      REAL_VALUE_TYPE d;
      long value;

      REAL_VALUE_FROM_CONST_DOUBLE (d, src);
      REAL_VALUE_TO_TARGET_SINGLE (d, value);

      output_asm_insn ("# ldconst	%1,%0",operands);
      operands[0] = gen_rtx (REG, SImode, REGNO (dst));
      operands[1] = gen_rtx (CONST_INT, VOIDmode, value);
      output_asm_insn (i960_output_ldconst (operands[0], operands[1]),
		      operands);
      return "";
    }
  else if (mode == TImode)
    {
      /* ??? This is currently not handled at all.  */
      abort ();

      /* Note: lowest order word goes in lowest numbered reg.  */
      rsrc1 = INTVAL (src);
      if (rsrc1 >= 0 && rsrc1 < 32)
	return "movq	%1,%0";
      else
	output_asm_insn ("movq\t0,%0\t# ldconstq %1,%0",operands);
      /* Go pick up the low-order word.  */
    }
  else if (mode == DImode)
    {
      rtx upperhalf, lowerhalf, xoperands[2];

      if (GET_CODE (src) == CONST_DOUBLE || GET_CODE (src) == CONST_INT)
 	split_double (src, &lowerhalf, &upperhalf);

      else
	abort ();

      /* Note: lowest order word goes in lowest numbered reg.  */
      /* Numbers from 0 to 31 can be handled with a single insn.  */
      rsrc1 = INTVAL (lowerhalf);
      if (upperhalf == const0_rtx && rsrc1 >= 0 && rsrc1 < 32)
	return "movl	%1,%0";

      /* Output the upper half with a recursive call.  */
      xoperands[0] = gen_rtx (REG, SImode, REGNO (dst) + 1);
      xoperands[1] = upperhalf;
      output_asm_insn (i960_output_ldconst (xoperands[0], xoperands[1]),
		       xoperands);
      /* The lower word is emitted as normally.  */
    }
  else
    {
      rsrc1 = INTVAL (src);
      if (mode == QImode)
	{
	  if (rsrc1 > 0xff)
	    rsrc1 &= 0xff;
	}
      else if (mode == HImode)
	{
	  if (rsrc1 > 0xffff)
	    rsrc1 &= 0xffff;
	}
    }

  if (rsrc1 >= 0)
    {
      /* ldconst	0..31,X		-> 	mov	0..31,X  */
      if (rsrc1 < 32)
	{
	  if (i960_last_insn_type == I_TYPE_REG && TARGET_C_SERIES)
	    return "lda	%1,%0";
	  return "mov	%1,%0";
	}

      /* ldconst	32..63,X	->	add	31,nn,X  */
      if (rsrc1 < 63)
	{
	  if (i960_last_insn_type == I_TYPE_REG && TARGET_C_SERIES)
	    return "lda	%1,%0";
	  operands[1] = gen_rtx (CONST_INT, VOIDmode, rsrc1 - 31);
	  output_asm_insn ("addo\t31,%1,%0\t# ldconst %3,%0", operands);
	  return "";
	}
    }
  else if (rsrc1 < 0)
    {
      /* ldconst	-1..-31		->	sub	0,0..31,X  */
      if (rsrc1 >= -31)
	{
	  /* return 'sub -(%1),0,%0' */
	  operands[1] = gen_rtx (CONST_INT, VOIDmode, - rsrc1);
	  output_asm_insn ("subo\t%1,0,%0\t# ldconst %3,%0", operands);
	  return "";
	}
      
      /* ldconst	-32		->	not	31,X  */
      if (rsrc1 == -32)
	{
	  operands[1] = gen_rtx (CONST_INT, VOIDmode, ~rsrc1);
	  output_asm_insn ("not\t%1,%0	# ldconst %3,%0", operands);
	  return "";
	}
    }

  /* If const is a single bit.  */
  if (bitpos (rsrc1) >= 0)
    {
      operands[1] = gen_rtx (CONST_INT, VOIDmode, bitpos (rsrc1));
      output_asm_insn ("setbit\t%1,0,%0\t# ldconst %3,%0", operands);
      return "";
    }

  /* If const is a bit string of less than 6 bits (1..31 shifted).  */
  if (is_mask (rsrc1))
    {
      int s, e;

      if (bitstr (rsrc1, &s, &e) < 6)
	{
	  rsrc2 = ((unsigned int) rsrc1) >> s;
	  operands[1] = gen_rtx (CONST_INT, VOIDmode, rsrc2);
	  operands[2] = gen_rtx (CONST_INT, VOIDmode, s);
	  output_asm_insn ("shlo\t%2,%1,%0\t# ldconst %3,%0", operands);
	  return "";
	}
    }

  /* Unimplemented cases:
     const is in range 0..31 but rotated around end of word:
     ror	31,3,g0	-> ldconst 0xe0000003,g0
   
     and any 2 instruction cases that might be worthwhile  */
  
  output_asm_insn ("ldconst	%1,%0", operands);
  return "";
}

/* Determine if there is an opportunity for a bypass optimization.
   Bypass succeeds on the 960K* if the destination of the previous
   instruction is the second operand of the current instruction.
   Bypass always succeeds on the C*.
 
   Return 1 if the pattern should interchange the operands.

   CMPBR_FLAG is true if this is for a compare-and-branch insn.
   OP1 and OP2 are the two source operands of a 3 operand insn.  */

int
i960_bypass (insn, op1, op2, cmpbr_flag)
     register rtx insn, op1, op2;
     int cmpbr_flag;
{
  register rtx prev_insn, prev_dest;

  if (TARGET_C_SERIES)
    return 0;

  /* Can't do this if op1 isn't a register.  */
  if (! REG_P (op1))
    return 0;

  /* Can't do this for a compare-and-branch if both ops aren't regs.  */
  if (cmpbr_flag && ! REG_P (op2))
    return 0;

  prev_insn = prev_real_insn (insn);

  if (prev_insn && GET_CODE (prev_insn) == INSN
      && GET_CODE (PATTERN (prev_insn)) == SET)
    {
      prev_dest = SET_DEST (PATTERN (prev_insn));
      if ((GET_CODE (prev_dest) == REG && REGNO (prev_dest) == REGNO (op1))
	  || (GET_CODE (prev_dest) == SUBREG
	      && GET_CODE (SUBREG_REG (prev_dest)) == REG
	      && REGNO (SUBREG_REG (prev_dest)) == REGNO (op1)))
	return 1;
    }
  return 0;
}

/* Output the code which declares the function name.  This also handles
   leaf routines, which have special requirements, and initializes some
   global variables.  */

void
i960_function_name_declare (file, name, fndecl)
     FILE *file;
     char *name;
     tree fndecl;
{
  register int i, j;
  int leaf_proc_ok;
  rtx insn;

  /* Increment global return label.  */

  ret_label++;

  /* Compute whether tail calls and leaf routine optimizations can be performed
     for this function.  */

  if (TARGET_TAILCALL)
    tail_call_ok = 1;
  else
    tail_call_ok = 0;

  if (TARGET_LEAFPROC)
    leaf_proc_ok = 1;
  else
    leaf_proc_ok = 0;

  /* Even if nobody uses extra parms, can't have leafproc or tail calls if
     argblock, because argblock uses g14 implicitly.  */

  if (current_function_args_size != 0 || VARARGS_STDARG_FUNCTION (fndecl))
    {
      tail_call_ok = 0;
      leaf_proc_ok = 0;
    }
      
  /* See if caller passes in an address to return value. */

  if (aggregate_value_p (DECL_RESULT (fndecl)))
    {
      tail_call_ok = 0;
      leaf_proc_ok = 0;
    }

  /* Can not use tail calls or make this a leaf routine if there is a non
     zero frame size.  */