m68k.c

gcc库的原代码,对编程有很大帮助.

#endif

  if (! inited_FPA_table)
    init_FPA_table ();

  REAL_VALUE_FROM_CONST_DOUBLE (r, x);

  for (i=0; i<12; i++)
    {
      if (REAL_VALUES_EQUAL (r, values_FPA[i]))
        return (codes_FPA[i]);
    }

  if (GET_MODE (x) == SFmode)
    {
      for (i=25; i<38; i++)
        {
          if (REAL_VALUES_EQUAL (r, values_FPA[i]))
            return (codes_FPA[i]);
        }
    }
  else
    {
      for (i=12; i<25; i++)
        {
          if (REAL_VALUES_EQUAL (r, values_FPA[i]))
            return (codes_FPA[i]);
        }
    }
  return 0x0;
}
#endif /* define SUPPORT_SUN_FPA */

/* A C compound statement to output to stdio stream STREAM the
   assembler syntax for an instruction operand X.  X is an RTL
   expression.

   CODE is a value that can be used to specify one of several ways
   of printing the operand.  It is used when identical operands
   must be printed differently depending on the context.  CODE
   comes from the `%' specification that was used to request
   printing of the operand.  If the specification was just `%DIGIT'
   then CODE is 0; if the specification was `%LTR DIGIT' then CODE
   is the ASCII code for LTR.

   If X is a register, this macro should print the register's name.
   The names can be found in an array `reg_names' whose type is
   `char *[]'.  `reg_names' is initialized from `REGISTER_NAMES'.

   When the machine description has a specification `%PUNCT' (a `%'
   followed by a punctuation character), this macro is called with
   a null pointer for X and the punctuation character for CODE.

   The m68k specific codes are:

   '.' for dot needed in Motorola-style opcode names.
   '-' for an operand pushing on the stack:
       sp@-, -(sp) or -(%sp) depending on the style of syntax.
   '+' for an operand pushing on the stack:
       sp@+, (sp)+ or (%sp)+ depending on the style of syntax.
   '@' for a reference to the top word on the stack:
       sp@, (sp) or (%sp) depending on the style of syntax.
   '#' for an immediate operand prefix (# in MIT and Motorola syntax
       but & in SGS syntax).
   '!' for the cc register (used in an `and to cc' insn).
   '$' for the letter `s' in an op code, but only on the 68040.
   '&' for the letter `d' in an op code, but only on the 68040.
   '/' for register prefix needed by longlong.h.

   'b' for byte insn (no effect, on the Sun; this is for the ISI).
   'd' to force memory addressing to be absolute, not relative.
   'f' for float insn (print a CONST_DOUBLE as a float rather than in hex)
   'w' for FPA insn (print a CONST_DOUBLE as a SunFPA constant rather
       than directly).  Second part of 'y' below.
   'x' for float insn (print a CONST_DOUBLE as a float rather than in hex),
       or print pair of registers as rx:ry.
   'y' for a FPA insn (print pair of registers as rx:ry).  This also outputs
       CONST_DOUBLE's as SunFPA constant RAM registers if
       possible, so it should not be used except for the SunFPA.

   */

void
print_operand (file, op, letter)
     FILE *file;		/* file to write to */
     rtx op;			/* operand to print */
     int letter;		/* %<letter> or 0 */
{
  int i;

  if (letter == '.')
    {
#ifdef MOTOROLA
      asm_fprintf (file, ".");
#endif
    }
  else if (letter == '#')
    {
      asm_fprintf (file, "%0I");
    }
  else if (letter == '-')
    {
#ifdef MOTOROLA
      asm_fprintf (file, "-(%Rsp)");
#else
      asm_fprintf (file, "%Rsp@-");
#endif
    }
  else if (letter == '+')
    {
#ifdef MOTOROLA
      asm_fprintf (file, "(%Rsp)+");
#else
      asm_fprintf (file, "%Rsp@+");
#endif
    }
  else if (letter == '@')
    {
#ifdef MOTOROLA
      asm_fprintf (file, "(%Rsp)");
#else
      asm_fprintf (file, "%Rsp@");
#endif
    }
  else if (letter == '!')
    {
      asm_fprintf (file, "%Rfpcr");
    }
  else if (letter == '$')
    {
      if (TARGET_68040_ONLY)
	{
	  fprintf (file, "s");
	}
    }
  else if (letter == '&')
    {
      if (TARGET_68040_ONLY)
	{
	  fprintf (file, "d");
	}
    }
  else if (letter == '/')
    {
      asm_fprintf (file, "%R");
    }
  else if (GET_CODE (op) == REG)
    {
#ifdef SUPPORT_SUN_FPA
      if (REGNO (op) < 16
	  && (letter == 'y' || letter == 'x')
	  && GET_MODE (op) == DFmode)
	{
	  fprintf (file, "%s:%s", reg_names[REGNO (op)],
		   reg_names[REGNO (op)+1]);
	}
      else
#endif
	{
	  if (letter == 'R')
	    /* Print out the second register name of a register pair.
	       I.e., R (6) => 7.  */
	    fputs (reg_names[REGNO (op) + 1], file);
	  else
	    fputs (reg_names[REGNO (op)], file);
	}
    }
  else if (GET_CODE (op) == MEM)
    {
      output_address (XEXP (op, 0));
      if (letter == 'd' && ! TARGET_68020
	  && CONSTANT_ADDRESS_P (XEXP (op, 0))
	  && !(GET_CODE (XEXP (op, 0)) == CONST_INT
	       && INTVAL (XEXP (op, 0)) < 0x8000
	       && INTVAL (XEXP (op, 0)) >= -0x8000))
	{
	  fprintf (file, ":l");
	}
    }
#ifdef SUPPORT_SUN_FPA
  else if ((letter == 'y' || letter == 'w')
	   && GET_CODE (op) == CONST_DOUBLE
	   && (i = standard_sun_fpa_constant_p (op)))
    {
      fprintf (file, "%%%d", i & 0x1ff);
    }
#endif
  else if (GET_CODE (op) == CONST_DOUBLE && GET_MODE (op) == SFmode)
    {
      REAL_VALUE_TYPE r;
      REAL_VALUE_FROM_CONST_DOUBLE (r, op);
      ASM_OUTPUT_FLOAT_OPERAND (letter, file, r);
    }
  else if (GET_CODE (op) == CONST_DOUBLE && GET_MODE (op) == XFmode)
    {
      REAL_VALUE_TYPE r;
      REAL_VALUE_FROM_CONST_DOUBLE (r, op);
      ASM_OUTPUT_LONG_DOUBLE_OPERAND (file, r);
    }
  else if (GET_CODE (op) == CONST_DOUBLE && GET_MODE (op) == DFmode)
    {
      REAL_VALUE_TYPE r;
      REAL_VALUE_FROM_CONST_DOUBLE (r, op);
      ASM_OUTPUT_DOUBLE_OPERAND (file, r);
    }
  else
    {
      asm_fprintf (file, "%0I"); output_addr_const (file, op);
    }
}


/* A C compound statement to output to stdio stream STREAM the
   assembler syntax for an instruction operand that is a memory
   reference whose address is ADDR.  ADDR is an RTL expression.

   Note that this contains a kludge that knows that the only reason
   we have an address (plus (label_ref...) (reg...)) when not generating
   PIC code is in the insn before a tablejump, and we know that m68k.md
   generates a label LInnn: on such an insn.

   It is possible for PIC to generate a (plus (label_ref...) (reg...))
   and we handle that just like we would a (plus (symbol_ref...) (reg...)).

   Some SGS assemblers have a bug such that "Lnnn-LInnn-2.b(pc,d0.l*2)"
   fails to assemble.  Luckily "Lnnn(pc,d0.l*2)" produces the results
   we want.  This difference can be accommodated by using an assembler
   define such "LDnnn" to be either "Lnnn-LInnn-2.b", "Lnnn", or any other
   string, as necessary.  This is accomplished via the ASM_OUTPUT_CASE_END
   macro.  See m68k/sgs.h for an example; for versions without the bug.
   Some assemblers refuse all the above solutions.  The workaround is to
   emit "K(pc,d0.l*2)" with K being a small constant known to give the
   right behaviour.

   They also do not like things like "pea 1.w", so we simple leave off
   the .w on small constants. 

   This routine is responsible for distinguishing between -fpic and -fPIC 
   style relocations in an address.  When generating -fpic code the
   offset is output in word mode (eg movel a5@(_foo:w), a0).  When generating
   -fPIC code the offset is output in long mode (eg movel a5@(_foo:l), a0) */

#ifndef ASM_OUTPUT_CASE_FETCH
#ifdef MOTOROLA
#ifdef SGS
#define ASM_OUTPUT_CASE_FETCH(file, labelno, regname)\
	asm_fprintf (file, "%LLD%d(%Rpc,%s.", labelno, regname)
#else
#define ASM_OUTPUT_CASE_FETCH(file, labelno, regname)\
	asm_fprintf (file, "%LL%d-%LLI%d.b(%Rpc,%s.", labelno, labelno, regname)
#endif
#else
#define ASM_OUTPUT_CASE_FETCH(file, labelno, regname)\
	asm_fprintf (file, "%Rpc@(%LL%d-%LLI%d-2:b,%s:", labelno, labelno, regname)
#endif
#endif /* ASM_OUTPUT_CASE_FETCH */

void
print_operand_address (file, addr)
     FILE *file;
     rtx addr;
{
  register rtx reg1, reg2, breg, ireg;
  rtx offset;

  switch (GET_CODE (addr))
    {
      case REG:
#ifdef MOTOROLA
	fprintf (file, "(%s)", reg_names[REGNO (addr)]);
#else
	fprintf (file, "%s@", reg_names[REGNO (addr)]);
#endif
	break;
      case PRE_DEC:
#ifdef MOTOROLA
	fprintf (file, "-(%s)", reg_names[REGNO (XEXP (addr, 0))]);
#else
	fprintf (file, "%s@-", reg_names[REGNO (XEXP (addr, 0))]);
#endif
	break;
      case POST_INC:
#ifdef MOTOROLA
	fprintf (file, "(%s)+", reg_names[REGNO (XEXP (addr, 0))]);
#else
	fprintf (file, "%s@+", reg_names[REGNO (XEXP (addr, 0))]);
#endif
	break;
      case PLUS:
	reg1 = reg2 = ireg = breg = offset = 0;
	if (CONSTANT_ADDRESS_P (XEXP (addr, 0)))
	  {
	    offset = XEXP (addr, 0);
	    addr = XEXP (addr, 1);
	  }
	else if (CONSTANT_ADDRESS_P (XEXP (addr, 1)))
	  {
	    offset = XEXP (addr, 1);
	    addr = XEXP (addr, 0);
	  }
	if (GET_CODE (addr) != PLUS)
	  {
	    ;
	  }
	else if (GET_CODE (XEXP (addr, 0)) == SIGN_EXTEND)
	  {
	    reg1 = XEXP (addr, 0);
	    addr = XEXP (addr, 1);
	  }
	else if (GET_CODE (XEXP (addr, 1)) == SIGN_EXTEND)
	  {
	    reg1 = XEXP (addr, 1);
	    addr = XEXP (addr, 0);
	  }
	else if (GET_CODE (XEXP (addr, 0)) == MULT)
	  {
	    reg1 = XEXP (addr, 0);
	    addr = XEXP (addr, 1);
	  }
	else if (GET_CODE (XEXP (addr, 1)) == MULT)
	  {
	    reg1 = XEXP (addr, 1);
	    addr = XEXP (addr, 0);
	  }
	else if (GET_CODE (XEXP (addr, 0)) == REG)
	  {
	    reg1 = XEXP (addr, 0);
	    addr = XEXP (addr, 1);
	  }
	else if (GET_CODE (XEXP (addr, 1)) == REG)
	  {
	    reg1 = XEXP (addr, 1);
	    addr = XEXP (addr, 0);
	  }
	if (GET_CODE (addr) == REG || GET_CODE (addr) == MULT
	    || GET_CODE (addr) == SIGN_EXTEND)
	  {
	    if (reg1 == 0)
	      {
		reg1 = addr;
	      }
	    else
	      {
		reg2 = addr;
	      }
	    addr = 0;
	  }
#if 0	/* for OLD_INDEXING */
	else if (GET_CODE (addr) == PLUS)
	  {
	    if (GET_CODE (XEXP (addr, 0)) == REG)
	      {
		reg2 = XEXP (addr, 0);
		addr = XEXP (addr, 1);
	      }
	    else if (GET_CODE (XEXP (addr, 1)) == REG)
	      {
		reg2 = XEXP (addr, 1);
		addr = XEXP (addr, 0);
	      }
	  }
#endif
	if (offset != 0)
	  {
	    if (addr != 0)
	      {
		abort ();
	      }
	    addr = offset;
	  }
	if ((reg1 && (GET_CODE (reg1) == SIGN_EXTEND
		      || GET_CODE (reg1) == MULT))
	    || (reg2 != 0 && REGNO_OK_FOR_BASE_P (REGNO (reg2))))
	  {
	    breg = reg2;
	    ireg = reg1;
	  }
	else if (reg1 != 0 && REGNO_OK_FOR_BASE_P (REGNO (reg1)))
	  {
	    breg = reg1;
	    ireg = reg2;
	  }
	if (ireg != 0 && breg == 0 && GET_CODE (addr) == LABEL_REF
	    && ! (flag_pic && ireg == pic_offset_table_rtx))
	  {
	    int scale = 1;
	    if (GET_CODE (ireg) == MULT)
	      {
		scale = INTVAL (XEXP (ireg, 1));
		ireg = XEXP (ireg, 0);
	      }
	    if (GET_CODE (ireg) == SIGN_EXTEND)
	      {
		ASM_OUTPUT_CASE_FETCH (file,
			     CODE_LABEL_NUMBER (XEXP (addr, 0)),
			     reg_names[REGNO (XEXP (ireg, 0))]);
		fprintf (file, "w");
	      }
	    else
	      {
		ASM_OUTPUT_CASE_FETCH (file,
			     CODE_LABEL_NUMBER (XEXP (addr, 0)),
			     reg_names[REGNO (ireg)]);
		fprintf (file, "l");
	      }
	    if (scale != 1)
	      {
#ifdef MOTOROLA
		fprintf (file, "*%d", scale);
#else
		fprintf (file, ":%d", scale);
#endif
	      }
	    putc (')', file);
	    break;
	  }
	if (breg != 0 && ireg == 0 && GET_CODE (addr) == LABEL_REF
	    && ! (flag_pic && breg == pic_offset_table_rtx))
	  {
	    ASM_OUTPUT_CASE_FETCH (file,
			 CODE_LABEL_NUMBER (XEXP (addr, 0)),
			 reg_names[REGNO (breg)]);
	    fprintf (file, "l)");
	    break;
	  }
	if (ireg != 0 || breg != 0)
	  {
	    int scale = 1;
	    if (breg == 0)
	      {
		abort ();
	      }
	    if (! flag_pic && addr && GET_CODE (addr) == LABEL_REF)
	      {
		abort ();
	      }
#ifdef MOTOROLA
	    if (addr != 0)
	      {
		output_addr_const (file, addr);
	        if (flag_pic && (breg == pic_offset_table_rtx))
	          fprintf (file, "@GOT");
	      }
	    fprintf (file, "(%s", reg_names[REGNO (breg)]);
	    if (ireg != 0)
	      {
		putc (',', file);
	      }
#else
	    fprintf (file, "%s@(", reg_names[REGNO (breg)]);
	    if (addr != 0)
	      {
		output_addr_const (file, addr);
	        if ((flag_pic == 1) && (breg == pic_offset_table_rtx))
	          fprintf (file, ":w");
	        if ((flag_pic == 2) && (breg == pic_offset_table_rtx))
	          fprintf (file, ":l");
	      }
	    if (addr != 0 && ireg != 0)
	      {
		putc (',', file);
	      }
#endif
	    if (ireg != 0 && GET_CODE (ireg) == MULT)
	      {
		scale = INTVAL (XEXP (ireg, 1));
		ireg = XEXP (ireg, 0);
	      }
	    if (ireg != 0 && GET_CODE (ireg) == SIGN_EXTEND)
	      {
#ifdef MOTOROLA
		fprintf (file, "%s.w", reg_names[REGNO (XEXP (ireg, 0))]);
#else
		fprintf (file, "%s:w", reg_names[REGNO (XEXP (ireg, 0))]);
#endif
	      }
	    else if (ireg != 0)
	      {
#ifdef MOTOROLA
		fprintf (file, "%s.l", reg_names[REGNO (ireg)]);
#else
		fprintf (file, "%s:l", reg_names[REGNO (ireg)]);
#endif
	      }
	    if (scale != 1)
	      {
#ifdef MOTOROLA
		fprintf (file, "*%d", scale);
#else
		fprintf (file, ":%d", scale);
#endif
	      }
	    putc (')', file);
	    break;
	  }
	else if (reg1 != 0 && GET_CODE (addr) == L