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/* expr.c -operands, expressions-

   Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,

   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2010, 2011,

   2012 Free Software Foundation, Inc.

   This file is part of GAS, the GNU Assembler.

   GAS is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   GAS is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with GAS; see the file COPYING.  If not, write to the Free

   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA

   02110-1301, USA.  */

/* This is really a branch office of as-read.c. I split it out to clearly

   distinguish the world of expressions from the world of statements.

   (It also gives smaller files to re-compile.)

   Here, "operand"s are of expressions, not instructions.  */

#define min(a, b)       ((a) < (b) ? (a) : (b))

#include "as.h"

#include "safe-ctype.h"

#include "obstack.h"

#ifdef HAVE_LIMITS_H

#include 

#endif

#ifndef CHAR_BIT

#define CHAR_BIT 8

#endif

static void floating_constant (expressionS * expressionP);

static valueT generic_bignum_to_int32 (void);

#ifdef BFD64

static valueT generic_bignum_to_int64 (void);

#endif

static void integer_constant (int radix, expressionS * expressionP);

static void mri_char_constant (expressionS *);

static void clean_up_expression (expressionS * expressionP);

static segT operand (expressionS *, enum expr_mode);

static operatorT operatorf (int *);

extern const char EXP_CHARS[], FLT_CHARS[];

/* We keep a mapping of expression symbols to file positions, so that

   we can provide better error messages.  */

struct expr_symbol_line {

  struct expr_symbol_line *next;

  symbolS *sym;

  char *file;

  unsigned int line;

};

static struct expr_symbol_line *expr_symbol_lines;

/* Build a dummy symbol to hold a complex expression.  This is how we

   build expressions up out of other expressions.  The symbol is put

   into the fake section expr_section.  */

symbolS *

make_expr_symbol (expressionS *expressionP)

{

  expressionS zero;

  symbolS *symbolP;

  struct expr_symbol_line *n;

  if (expressionP->X_op == O_symbol

      && expressionP->X_add_number == 0)

    return expressionP->X_add_symbol;

  if (expressionP->X_op == O_big)

    {

      /* This won't work, because the actual value is stored in

	 generic_floating_point_number or generic_bignum, and we are

	 going to lose it if we haven't already.  */

      if (expressionP->X_add_number > 0)

	as_bad (_("bignum invalid"));

      else

	as_bad (_("floating point number invalid"));

      zero.X_op = O_constant;

      zero.X_add_number = 0;

      zero.X_unsigned = 0;

      zero.X_extrabit = 0;

      clean_up_expression (&zero);

      expressionP = &zero;

    }

  /* Putting constant symbols in absolute_section rather than

     expr_section is convenient for the old a.out code, for which

     S_GET_SEGMENT does not always retrieve the value put in by

     S_SET_SEGMENT.  */

  symbolP = symbol_create (FAKE_LABEL_NAME,

			   (expressionP->X_op == O_constant

			    ? absolute_section

			    : expressionP->X_op == O_register

			      ? reg_section

			      : expr_section),

			   0, &zero_address_frag);

  symbol_set_value_expression (symbolP, expressionP);

  if (expressionP->X_op == O_constant)

    resolve_symbol_value (symbolP);

  n = (struct expr_symbol_line *) xmalloc (sizeof *n);

  n->sym = symbolP;

  as_where (&n->file, &n->line);

  n->next = expr_symbol_lines;

  expr_symbol_lines = n;

  return symbolP;

}

/* Return the file and line number for an expr symbol.  Return

   non-zero if something was found, 0 if no information is known for

   the symbol.  */

int

expr_symbol_where (symbolS *sym, char **pfile, unsigned int *pline)

{

  register struct expr_symbol_line *l;

  for (l = expr_symbol_lines; l != NULL; l = l->next)

    {

      if (l->sym == sym)

	{

	  *pfile = l->file;

	  *pline = l->line;

	  return 1;

	}

    }

  return 0;

}

/* Utilities for building expressions.

   Since complex expressions are recorded as symbols for use in other

   expressions these return a symbolS * and not an expressionS *.

   These explicitly do not take an "add_number" argument.  */

/* ??? For completeness' sake one might want expr_build_symbol.

   It would just return its argument.  */

/* Build an expression for an unsigned constant.

   The corresponding one for signed constants is missing because

   there's currently no need for it.  One could add an unsigned_p flag

   but that seems more clumsy.  */

symbolS *

expr_build_uconstant (offsetT value)

{

  expressionS e;

  e.X_op = O_constant;

  e.X_add_number = value;

  e.X_unsigned = 1;

  e.X_extrabit = 0;

  return make_expr_symbol (&e);

}

/* Build an expression for the current location ('.').  */

symbolS *

expr_build_dot (void)

{

  expressionS e;

  current_location (&e);

  return symbol_clone_if_forward_ref (make_expr_symbol (&e));

}

/* Build any floating-point literal here.

   Also build any bignum literal here.  */

/* Seems atof_machine can backscan through generic_bignum and hit whatever

   happens to be loaded before it in memory.  And its way too complicated

   for me to fix right.  Thus a hack.  JF:  Just make generic_bignum bigger,

   and never write into the early words, thus they'll always be zero.

   I hate Dean's floating-point code.  Bleh.  */

LITTLENUM_TYPE generic_bignum[SIZE_OF_LARGE_NUMBER + 6];

FLONUM_TYPE generic_floating_point_number = {

  &generic_bignum[6],		/* low.  (JF: Was 0)  */

  &generic_bignum[SIZE_OF_LARGE_NUMBER + 6 - 1], /* high.  JF: (added +6)  */

  0,				/* leader.  */

  0,				/* exponent.  */

};

static void

floating_constant (expressionS *expressionP)

{

  /* input_line_pointer -> floating-point constant.  */

  int error_code;

  error_code = atof_generic (&input_line_pointer, ".", EXP_CHARS,

			     &generic_floating_point_number);

  if (error_code)

    {

      if (error_code == ERROR_EXPONENT_OVERFLOW)

	{

	  as_bad (_("bad floating-point constant: exponent overflow"));

	}

      else

	{

	  as_bad (_("bad floating-point constant: unknown error code=%d"),

		  error_code);

	}

    }

  expressionP->X_op = O_big;

  /* input_line_pointer -> just after constant, which may point to

     whitespace.  */

  expressionP->X_add_number = -1;

}

static valueT

generic_bignum_to_int32 (void)

{

  valueT number =

	   ((generic_bignum[1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS)

	   | (generic_bignum[0] & LITTLENUM_MASK);

  number &= 0xffffffff;

  return number;

}

#ifdef BFD64

static valueT

generic_bignum_to_int64 (void)

{

  valueT number =

    ((((((((valueT) generic_bignum[3] & LITTLENUM_MASK)

	  << LITTLENUM_NUMBER_OF_BITS)

	 | ((valueT) generic_bignum[2] & LITTLENUM_MASK))

	<< LITTLENUM_NUMBER_OF_BITS)

       | ((valueT) generic_bignum[1] & LITTLENUM_MASK))

      << LITTLENUM_NUMBER_OF_BITS)

     | ((valueT) generic_bignum[0] & LITTLENUM_MASK));

  return number;

}

#endif

static void

integer_constant (int radix, expressionS *expressionP)

{

  char *start;		/* Start of number.  */

  char *suffix = NULL;

  char c;

  valueT number;	/* Offset or (absolute) value.  */

  short int digit;	/* Value of next digit in current radix.  */

  short int maxdig = 0;	/* Highest permitted digit value.  */

  int too_many_digits = 0;	/* If we see >= this number of.  */

  char *name;		/* Points to name of symbol.  */

  symbolS *symbolP;	/* Points to symbol.  */

  int small;			/* True if fits in 32 bits.  */

  /* May be bignum, or may fit in 32 bits.  */

  /* Most numbers fit into 32 bits, and we want this case to be fast.

     so we pretend it will fit into 32 bits.  If, after making up a 32

     bit number, we realise that we have scanned more digits than

     comfortably fit into 32 bits, we re-scan the digits coding them

     into a bignum.  For decimal and octal numbers we are

     conservative: Some numbers may be assumed bignums when in fact

     they do fit into 32 bits.  Numbers of any radix can have excess

     leading zeros: We strive to recognise this and cast them back

     into 32 bits.  We must check that the bignum really is more than

     32 bits, and change it back to a 32-bit number if it fits.  The

     number we are looking for is expected to be positive, but if it

     fits into 32 bits as an unsigned number, we let it be a 32-bit

     number.  The cavalier approach is for speed in ordinary cases.  */

  /* This has been extended for 64 bits.  We blindly assume that if

     you're compiling in 64-bit mode, the target is a 64-bit machine.

     This should be cleaned up.  */

#ifdef BFD64

#define valuesize 64

#else /* includes non-bfd case, mostly */

#define valuesize 32

#endif

  if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri) && radix == 0)

    {

      int flt = 0;

      /* In MRI mode, the number may have a suffix indicating the

	 radix.  For that matter, it might actually be a floating

	 point constant.  */

      for (suffix = input_line_pointer; ISALNUM (*suffix); suffix++)

	{

	  if (*suffix == 'e' || *suffix == 'E')

	    flt = 1;

	}

      if (suffix == input_line_pointer)

	{

	  radix = 10;

	  suffix = NULL;

	}

      else

	{

	  c = *--suffix;

	  c = TOUPPER (c);

	  /* If we have both NUMBERS_WITH_SUFFIX and LOCAL_LABELS_FB,

	     we distinguish between 'B' and 'b'.  This is the case for

	     Z80.  */

	  if ((NUMBERS_WITH_SUFFIX && LOCAL_LABELS_FB ? *suffix : c) == 'B')

	    radix = 2;

	  else if (c == 'D')

	    radix = 10;

	  else if (c == 'O' || c == 'Q')

	    radix = 8;

	  else if (c == 'H')

	    radix = 16;

	  else if (suffix[1] == '.' || c == 'E' || flt)

	    {

	      floating_constant (expressionP);

	      return;

	    }

	  else

	    {

	      radix = 10;

	      suffix = NULL;

	    }

	}

    }

  switch (radix)

    {

    case 2:

      maxdig = 2;

      too_many_digits = valuesize + 1;

      break;

    case 8:

      maxdig = radix = 8;

      too_many_digits = (valuesize + 2) / 3 + 1;

      break;

    case 16:

      maxdig = radix = 16;

      too_many_digits = (valuesize + 3) / 4 + 1;

      break;

    case 10:

      maxdig = radix = 10;

      too_many_digits = (valuesize + 11) / 4; /* Very rough.  */

    }

#undef valuesize

  start = input_line_pointer;

  c = *input_line_pointer++;

  for (number = 0;

       (digit = hex_value (c)) < maxdig;

       c = *input_line_pointer++)

    {

      number = number * radix + digit;

    }

  /* c contains character after number.  */

  /* input_line_pointer->char after c.  */

  small = (input_line_pointer - start - 1) < too_many_digits;

  if (radix == 16 && c == '_')

    {

      /* This is literal of the form 0x333_0_12345678_1.

	 This example is equivalent to 0x00000333000000001234567800000001.  */

      int num_little_digits = 0;

      int i;

      input_line_pointer = start;	/* -> 1st digit.  */

      know (LITTLENUM_NUMBER_OF_BITS == 16);

      for (c = '_'; c == '_'; num_little_digits += 2)

	{

	  /* Convert one 64-bit word.  */

	  int ndigit = 0;

	  number = 0;

	  for (c = *input_line_pointer++;

	       (digit = hex_value (c)) < maxdig;

	       c = *(input_line_pointer++))

	    {

	      number = number * radix + digit;

	      ndigit++;

	    }

	  /* Check for 8 digit per word max.  */

	  if (ndigit > 8)

	    as_bad (_("a bignum with underscores may not have more than 8 hex digits in any word"));

	  /* Add this chunk to the bignum.

	     Shift things down 2 little digits.  */

	  know (LITTLENUM_NUMBER_OF_BITS == 16);

	  for (i = min (num_little_digits + 1, SIZE_OF_LARGE_NUMBER - 1);

	       i >= 2;

	       i--)

	    generic_bignum[i] = generic_bignum[i - 2];

	  /* Add the new digits as the least significant new ones.  */

	  generic_bignum[0] = number & 0xffffffff;

	  generic_bignum[1] = number >> 16;

	}

      /* Again, c is char after number, input_line_pointer->after c.  */

      if (num_little_digits > SIZE_OF_LARGE_NUMBER - 1)

	num_little_digits = SIZE_OF_LARGE_NUMBER - 1;

      gas_assert (num_little_digits >= 4);

      if (num_little_digits != 8)

	as_bad (_("a bignum with underscores must have exactly 4 words"));

      /* We might have some leading zeros.  These can be trimmed to give

	 us a change to fit this constant into a small number.  */

      while (generic_bignum[num_little_digits - 1] == 0

	     && num_little_digits > 1)

	num_little_digits--;

      if (num_little_digits <= 2)

	{

	  /* will fit into 32 bits.  */

	  number = generic_bignum_to_int32 ();

	  small = 1;

	}

#ifdef BFD64

      else if (num_little_digits <= 4)

	{

	  /* Will fit into 64 bits.  */

	  number = generic_bignum_to_int64 ();

	  small = 1;

	}

#endif

      else

	{

	  small = 0;

	  /* Number of littlenums in the bignum.  */

	  number = num_little_digits;

	}

    }

  else if (!small)

    {

      /* We saw a lot of digits. manufacture a bignum the hard way.  */

      LITTLENUM_TYPE *leader;	/* -> high order littlenum of the bignum.  */

      LITTLENUM_TYPE *pointer;	/* -> littlenum we are frobbing now.  */

      long carry;

      leader = generic_bignum;

      generic_bignum[0] = 0;

      generic_bignum[1] = 0;

      generic_bignum[2] = 0;

      generic_bignum[3] = 0;

      input_line_pointer = start;	/* -> 1st digit.  */

      c = *input_line_pointer++;

      for (; (carry = hex_value (c)) < maxdig; c = *input_line_pointer++)

	{

	  for (pointer = generic_bignum; pointer <= leader; pointer++)

	    {

	      long work;

	      work = carry + radix * *pointer;

	      *pointer = work & LITTLENUM_MASK;

	      carry = work >> LITTLENUM_NUMBER_OF_BITS;

	    }

	  if (carry)

	    {

	      if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1)

		{

		  /* Room to grow a longer bignum.  */

		  *++leader = carry;

		}

	    }

	}

      /* Again, c is char after number.  */

      /* input_line_pointer -> after c.  */

      know (LITTLENUM_NUMBER_OF_BITS == 16);

      if (leader < generic_bignum + 2)

	{

	  /* Will fit into 32 bits.  */

	  number = generic_bignum_to_int32 ();

	  small = 1;

	}

#ifdef BFD64

      else if (leader < generic_bignum + 4)

	{

	  /* Will fit into 64 bits.  */

	  number = generic_bignum_to_int64 ();

	  small = 1;

	}

#endif

      else

	{

	  /* Number of littlenums in the bignum.  */

	  number = leader - generic_bignum + 1;

	}

    }

  if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)

      && suffix != NULL

      && input_line_pointer - 1 == suffix)

    c = *input_line_pointer++;

  if (small)

    {

      /* Here with number, in correct radix. c is the next char.

	 Note that unlike un*x, we allow "011f" "0x9f" to both mean

	 the same as the (conventional) "9f".

	 This is simply easier than checking for strict canonical

	 form.  Syntax sux!  */

      if (LOCAL_LABELS_FB && c == 'b')

	{

	  /* Backward ref to local label.

	     Because it is backward, expect it to be defined.  */

	  /* Construct a local label.  */

	  name = fb_label_name ((int) number, 0);

	  /* Seen before, or symbol is defined: OK.  */

	  symbolP = symbol_find (name);

	  if ((symbolP != NULL) && (S_IS_DEFINED (symbolP)))

	    {

	      /* Local labels are never absolute.  Don't waste time

		 checking absoluteness.  */

	      know (SEG_NORMAL (S_GET_SEGMENT (symbolP)));

	      expressionP->X_op = O_symbol;

	      expressionP->X_add_symbol = symbolP;

	    }

	  else

	    {

	      /* Either not seen or not defined.  */

	      /* @@ Should print out the original string instead of

		 the parsed number.  */

	      as_bad (_("backward ref to unknown label \"%d:\""),

		      (int) number);

	      expressionP->X_op = O_constant;

	    }

	  expressionP->X_add_number = 0;

	}			/* case 'b' */

      else if (LOCAL_LABELS_FB && c == 'f')

	{

	  /* Forward reference.  Expect symbol to be undefined or

	     unknown.  undefined: seen it before.  unknown: never seen

	     it before.

	     Construct a local label name, then an undefined symbol.

	     Don't create a xseg frag for it: caller may do that.

	     Just return it as never seen before.  */

	  name = fb_label_name ((int) number, 1);

	  symbolP = symbol_find_or_make (name);

	  /* We have no need to check symbol properties.  */

#ifndef many_segments

	  /* Since "know" puts its arg into a "string", we

	     can't have newlines in the argument.  */

	  know (S_GET_SEGMENT (symbolP) == undefined_section || S_GET_SEGMENT (symbolP) == text_section || S_GET_SEGMENT (symbolP) == data_section);

#endif

	  expressionP->X_op = O_symbol;

	  expressionP->X_add_symbol = symbolP;

	  expressionP->X_add_number = 0;

	}			/* case 'f' */

      else if (LOCAL_LABELS_DOLLAR && c == '$')

	{

	  /* If the dollar label is *currently* defined, then this is just

	     another reference to it.  If it is not *currently* defined,

	     then this is a fresh instantiation of that number, so create

	     it.  */

	  if (dollar_label_defined ((long) number))

	    {

	      name = dollar_label_name ((long) number, 0);

	      symbolP = symbol_find (name);

	      know (symbolP != NULL);

	    }

	  else

	    {

	      name = dollar_label_name ((long) number, 1);

	      symbolP = symbol_find_or_make (name);

	    }

	  expressionP->X_op = O_symbol;

	  expressionP->X_add_symbol = symbolP;

	  expressionP->X_add_number = 0;

	}			/* case '$' */

      else

	{

	  expressionP->X_op = O_constant;

	  expressionP->X_add_number = number;

	  input_line_pointer--;	/* Restore following character.  */

	}			/* Really just a number.  */

    }

  else

    {

      /* Not a small number.  */

      expressionP->X_op = O_big;

      expressionP->X_add_number = number;	/* Number of littlenums.  */

      input_line_pointer--;	/* -> char following number.  */

    }

}

/* Parse an MRI multi character constant.  */

static void

mri_char_constant (expressionS *expressionP)

{

  int i;

  if (*input_line_pointer == '\''

      && input_line_pointer[1] != '\'')

    {

      expressionP->X_op = O_constant;

      expressionP->X_add_number = 0;

      return;

    }

  /* In order to get the correct byte ordering, we must build the

     number in reverse.  */

  for (i = SIZE_OF_LARGE_NUMBER - 1; i >= 0; i--)

    {

      int j;

      generic_bignum[i] = 0;

      for (j = 0; j < CHARS_PER_LITTLENUM; j++)

	{

	  if (*input_line_pointer == '\'')

	    {

	      if (input_line_pointer[1] != '\'')

		break;

	      ++input_line_pointer;

	    }

	  generic_bignum[i] <<= 8;

	  generic_bignum[i] += *input_line_pointer;

	  ++input_line_pointer;

	}

      if (i < SIZE_OF_LARGE_NUMBER - 1)

	{

	  /* If there is more than one littlenum, left justify the

	     last one to make it match the earlier ones.  If there is

	     only one, we can just use the value directly.  */

	  for (; j < CHARS_PER_LITTLENUM; j++)

	    generic_bignum[i] <<= 8;

	}

      if (*input_line_pointer == '\''

	  && input_line_pointer[1] != '\'')

	break;

    }

  if (i < 0)

    {

      as_bad (_("character constant too large"));

      i = 0;

    }

  if (i > 0)

    {

      int c;

      int j;

      c = SIZE_OF_LARGE_NUMBER - i;

      for (j = 0; j < c; j++)

	generic_bignum[j] = generic_bignum[i + j];

      i = c;

    }

  know (LITTLENUM_NUMBER_OF_BITS == 16);

  if (i > 2)

    {

      expressionP->X_op = O_big;

      expressionP->X_add_number = i;

    }

  else

    {

      expressionP->X_op = O_constant;

      if (i < 2)

	expressionP->X_add_number = generic_bignum[0] & LITTLENUM_MASK;

      else

	expressionP->X_add_number =

	  (((generic_bignum[1] & LITTLENUM_MASK)

	    << LITTLENUM_NUMBER_OF_BITS)

	   | (generic_bignum[0] & LITTLENUM_MASK));

    }

  /* Skip the final closing quote.  */

  ++input_line_pointer;

}

/* Return an expression representing the current location.  This

   handles the magic symbol `.'.  */

void

current_location (expressionS *expressionp)

{

  if (now_seg == absolute_section)

    {

      expressionp->X_op = O_constant;

      expressionp->X_add_number = abs_section_offset;

    }

  else

    {

      expressionp->X_op = O_symbol;

      expressionp->X_add_symbol = &dot_symbol;

      expressionp->X_add_number = 0;

    }

}

/* In:	Input_line_pointer points to 1st char of operand, which may

	be a space.

   Out:	An expressionS.

	The operand may have been empty: in this case X_op == O_absent.

	Input_line_pointer->(next non-blank) char after operand.  */

static segT

operand (expressionS *expressionP, enum expr_mode mode)

{

  char c;

  symbolS *symbolP;	/* Points to symbol.  */

  char *name;		/* Points to name of symbol.  */

  segT segment;

  /* All integers are regarded as unsigned unless they are negated.

     This is because the only thing which cares whether a number is

     unsigned is the code in emit_expr which extends constants into

     bignums.  It should only sign extend negative numbers, so that

     something like ``.quad 0x80000000'' is not sign extended even

     though it appears negative if valueT is 32 bits.  */

  expressionP->X_unsigned = 1;

  expressionP->X_extrabit = 0;

  /* Digits, assume it is a bignum.  */

  SKIP_WHITESPACE ();		/* Leading whitespace is part of operand.  */

  c = *input_line_pointer++;	/* input_line_pointer -> past char in c.  */

  if (is_end_of_line[(unsigned char) c])

    goto eol;

  switch (c)

    {

    case '1':

    case '2':

    case '3':

    case '4':

    case '5':

    case '6':

    case '7':

    case '8':

    case '9':

      input_line_pointer--;

      integer_constant ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)

			? 0 : 10,

			expressionP);

      break;

#ifdef LITERAL_PREFIXDOLLAR_HEX

    case '$':

      /* $L is the start of a local label, not a hex constant.  */

      if (* input_line_pointer == 'L')

      goto isname;

      integer_constant (16, expressionP);

      break;

#endif

#ifdef LITERAL_PREFIXPERCENT_BIN

    case '%':

      integer_constant (2, expressionP);

      break;

#endif

    case '0':

      /* Non-decimal radix.  */

      if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)

	{

	  char *s;

	  /* Check for a hex or float constant.  */

	  for (s = input_line_pointer; hex_p (*s); s++)

	    ;

	  if (*s == 'h' || *s == 'H' || *input_line_pointer == '.')

	    {

	      --input_line_pointer;

	      integer_constant (0, expressionP);

	      break;

	    }

	}

      c = *input_line_pointer;

      switch (c)

	{

	case 'o':

	case 'O':

	case 'q':

	case 'Q':

	case '8':

	case '9':

	  if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)

	    {

	      integer_constant (0, expressionP);

	      break;

	    }

	  /* Fall through.  */

	default:

	default_case:

	  if (c && strchr (FLT_CHARS, c))

	    {

	      input_line_pointer++;

	      floating_constant (expressionP);

	      expressionP->X_add_number = - TOLOWER (c);

	    }

	  else

	    {

	      /* The string was only zero.  */

	      expressionP->X_op = O_constant;

	      expressionP->X_add_number = 0;

	    }

	  break;

	case 'x':

	case 'X':

	  if (flag_m68k_mri)

	    goto default_case;

	  input_line_pointer++;

	  integer_constant (16, expressionP);

	  break;

	case 'b':

	  if (LOCAL_LABELS_FB && ! (flag_m68k_mri || NUMBERS_WITH_SUFFIX))

	    {

	      /* This code used to check for '+' and '-' here, and, in

		 some conditions, fall through to call

		 integer_constant.  However, that didn't make sense,

		 as integer_constant only accepts digits.  */

	      /* Some of our code elsewhere does permit digits greater

		 than the expected base; for consistency, do the same

		 here.  */

	      if (input_line_pointer[1] < '0'

		  || input_line_pointer[1] > '9')

		{

		  /* Parse this as a back reference to label 0.  */

		  input_line_pointer--;

		  integer_constant (10, expressionP);

		  break;

		}

	      /* Otherwise, parse this as a binary number.  */

	    }

	  /* Fall through.  */

	case 'B':

	  input_line_pointer++;

	  if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)

	    goto default_case;

	  integer_constant (2, expressionP);

	  break;

	case '0':

	case '1':

	case '2':

	case '3':

	case '4':

	case '5':

	case '6':

	case '7':

	  integer_constant ((flag_m68k_mri || NUMBERS_WITH_SUFFIX)

			    ? 0 : 8,

			    expressionP);

	  break;

	case 'f':

	  if (LOCAL_LABELS_FB)

	    {

	      /* If it says "0f" and it could possibly be a floating point

		 number, make it one.  Otherwise, make it a local label,

		 and try to deal with parsing the rest later.  */

	      if (!input_line_pointer[1]

		  || (is_end_of_line[0xff & input_line_pointer[1]])

		  || strchr (FLT_CHARS, 'f') == NULL)

		goto is_0f_label;

	      {

		char *cp = input_line_pointer + 1;

		int r = atof_generic (&cp, ".", EXP_CHARS,

				      &generic_floating_point_number);

		switch (r)

		  {

		  case 0:

		  case ERROR_EXPONENT_OVERFLOW:

		    if (*cp == 'f' || *cp == 'b')

		      /* Looks like a difference expression.  */

		      goto is_0f_label;

		    else if (cp == input_line_pointer + 1)

		      /* No characters has been accepted -- looks like

			 end of operand.  */

		      goto is_0f_label;

		    else

		      goto is_0f_float;

		  default:

		    as_fatal (_("expr.c(operand): bad atof_generic return val %d"),

			      r);

		  }

	      }

	      /* Okay, now we've sorted it out.  We resume at one of these

		 two labels, depending on what we've decided we're probably

		 looking at.  */

	    is_0f_label:

	      input_line_pointer--;

	      integer_constant (10, expressionP);

	      break;

	    is_0f_float:

	      /* Fall through.  */

	      ;

	    }

	case 'd':

	case 'D':

	  if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)

	    {

	      integer_constant (0, expressionP);

	      break;

	    }

	  /* Fall through.  */

	case 'F':

	case 'r':

	case 'e':

	case 'E':

	case 'g':

	case 'G':

	  input_line_pointer++;

	  floating_constant (expressionP);

	  expressionP->X_add_number = - TOLOWER (c);

	  break;

	case '$':

	  if (LOCAL_LABELS_DOLLAR)

	    {

	      integer_constant (10, expressionP);

	      break;

	    }

	  else

	    goto default_case;

	}

      break;

#ifndef NEED_INDEX_OPERATOR

    case '[':

# ifdef md_need_index_operator

      if (md_need_index_operator())

	goto de_fault;

# endif

      /* FALLTHROUGH */

#endif

    case '(':

      /* Didn't begin with digit & not a name.  */

      segment = expr (0, expressionP, mode);

      /* expression () will pass trailing whitespace.  */

      if ((c == '(' && *input_line_pointer != ')')

	  || (c == '[' && *input_line_pointer != ']'))

	as_bad (_("missing '%c'"), c == '(' ? ')' : ']');

      else

	input_line_pointer++;

      SKIP_WHITESPACE ();

      /* Here with input_line_pointer -> char after "(...)".  */

      return segment;

#ifdef TC_M68K

    case 'E':

      if (! flag_m68k_mri || *input_line_pointer != '\'')

	goto de_fault;

      as_bad (_("EBCDIC constants are not supported"));

      /* Fall through.  */

    case 'A':

      if (! flag_m68k_mri || *input_line_pointer != '\'')

	goto de_fault;

      ++input_line_pointer;

      /* Fall through.  */

#endif

    case '\'':

      if (! flag_m68k_mri)

	{

	  /* Warning: to conform to other people's assemblers NO

	     ESCAPEMENT is permitted for a single quote.  The next

	     character, parity errors and all, is taken as the value

	     of the operand.  VERY KINKY.  */

	  expressionP->X_op = O_constant;

	  expressionP->X_add_number = *input_line_pointer++;

	  break;

	}

      mri_char_constant (expressionP);

      break;

#ifdef TC_M68K

    case '"':

      /* Double quote is the bitwise not operator in MRI mode.  */

      if (! flag_m68k_mri)

	goto de_fault;

      /* Fall through.  */

#endif

    case '~':

      /* '~' is permitted to start a label on the Delta.  */

      if (is_name_beginner (c))

	goto isname;

    case '!':

    case '-':

    case '+':

      {

#ifdef md_operator

      unary:

#endif

	operand (expressionP, mode);

	if (expressionP->X_op == O_constant)

	  {

	    /* input_line_pointer -> char after operand.  */

	    if (c == '-')

	      {

		expressionP->X_add_number = - expressionP->X_add_number;

		/* Notice: '-' may overflow: no warning is given.

		   This is compatible with other people's

		   assemblers.  Sigh.  */

		expressionP->X_unsigned = 0;

		if (expressionP->X_add_number)

		  expressionP->X_extrabit ^= 1;

	      }

	    else if (c == '~' || c == '"')

	      expressionP->X_add_number = ~ expressionP->X_add_number;

	    else if (c == '!')

	      expressionP->X_add_number = ! expressionP->X_add_number;

	  }

	else if (expressionP->X_op == O_big

		 && expressionP->X_add_number <= 0

		 && c == '-'

		 && (generic_floating_point_number.sign == '+'

		     || generic_floating_point_number.sign == 'P'))

	  {

	    /* Negative flonum (eg, -1.000e0).  */

	    if (generic_floating_point_number.sign == '+')

	      generic_floating_point_number.sign = '-';

	    else

	      generic_floating_point_number.sign = 'N';

	  }

	else if (expressionP->X_op == O_big

		 && expressionP->X_add_number > 0)

	  {

	    int i;

	    if (c == '~' || c == '-')

	      {

		for (i = 0; i < expressionP->X_add_number; ++i)

		  generic_bignum[i] = ~generic_bignum[i];

		/* Extend the bignum to at least the size of .octa.  */

		if (expressionP->X_add_number < SIZE_OF_LARGE_NUMBER)

		  {

		    expressionP->X_add_number = SIZE_OF_LARGE_NUMBER;

		    for (; i < expressionP->X_add_number; ++i)

		      generic_bignum[i] = ~(LITTLENUM_TYPE) 0;

		  }

		if (c == '-')

		  for (i = 0; i < expressionP->X_add_number; ++i)

		    {

		      generic_bignum[i] += 1;

		      if (generic_bignum[i])

			break;

		    }

	      }

	    else if (c == '!')

	      {

		for (i = 0; i < expressionP->X_add_number; ++i)

		  if (generic_bignum[i] != 0)

		    break;

		expressionP->X_add_number = i >= expressionP->X_add_number;

		expressionP->X_op = O_constant;

		expressionP->X_unsigned = 1;

		expressionP->X_extrabit = 0;

	      }

	  }

	else if (expressionP->X_op != O_illegal

		 && expressionP->X_op != O_absent)

	  {

	    if (c != '+')

	      {

		expressionP->X_add_symbol = make_expr_symbol (expressionP);

		if (c == '-')

		  expressionP->X_op = O_uminus;

		else if (c == '~' || c == '"')

		  expressionP->X_op = O_bit_not;

		else

		  expressionP->X_op = O_logical_not;

		expressionP->X_add_number = 0;

	      }

	  }

	else

	  as_warn (_("Unary operator %c ignored because bad operand follows"),

		   c);

      }

      break;

#if defined (DOLLAR_DOT) || defined (TC_M68K)

    case '$':

      /* '$' is the program counter when in MRI mode, or when

	 DOLLAR_DOT is defined.  */

#ifndef DOLLAR_DOT

      if (! flag_m68k_mri)

	goto de_fault;

#endif

      if (DOLLAR_AMBIGU && hex_p (*input_line_pointer))

	{

	  /* In MRI mode and on Z80, '$' is also used as the prefix

	     for a hexadecimal constant.  */

	  integer_constant (16, expressionP);

	  break;

	}

      if (is_part_of_name (*input_line_pointer))

	goto isname;

      current_location (expressionP);