xref: /netbsd-src/external/gpl3/binutils.old/dist/gas/expr.c (revision 82d56013d7b633d116a93943de88e08335357a7c)
1 /* expr.c -operands, expressions-
2    Copyright (C) 1987-2018 Free Software Foundation, Inc.
3 
4    This file is part of GAS, the GNU Assembler.
5 
6    GAS is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3, or (at your option)
9    any later version.
10 
11    GAS is distributed in the hope that it will be useful,
12    but WITHOUT ANY WARRANTY; without even the implied warranty of
13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with GAS; see the file COPYING.  If not, write to the Free
18    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
19    02110-1301, USA.  */
20 
21 /* This is really a branch office of as-read.c. I split it out to clearly
22    distinguish the world of expressions from the world of statements.
23    (It also gives smaller files to re-compile.)
24    Here, "operand"s are of expressions, not instructions.  */
25 
26 #define min(a, b)       ((a) < (b) ? (a) : (b))
27 
28 #include "as.h"
29 #include "safe-ctype.h"
30 
31 #ifdef HAVE_LIMITS_H
32 #include <limits.h>
33 #endif
34 #ifndef CHAR_BIT
35 #define CHAR_BIT 8
36 #endif
37 
38 static void floating_constant (expressionS * expressionP);
39 static valueT generic_bignum_to_int32 (void);
40 #ifdef BFD64
41 static valueT generic_bignum_to_int64 (void);
42 #endif
43 static void integer_constant (int radix, expressionS * expressionP);
44 static void mri_char_constant (expressionS *);
45 static void clean_up_expression (expressionS * expressionP);
46 static segT operand (expressionS *, enum expr_mode);
47 static operatorT operatorf (int *);
48 
49 /* We keep a mapping of expression symbols to file positions, so that
50    we can provide better error messages.  */
51 
52 struct expr_symbol_line {
53   struct expr_symbol_line *next;
54   symbolS *sym;
55   const char *file;
56   unsigned int line;
57 };
58 
59 static struct expr_symbol_line *expr_symbol_lines;
60 
61 /* Build a dummy symbol to hold a complex expression.  This is how we
62    build expressions up out of other expressions.  The symbol is put
63    into the fake section expr_section.  */
64 
65 symbolS *
66 make_expr_symbol (expressionS *expressionP)
67 {
68   expressionS zero;
69   symbolS *symbolP;
70   struct expr_symbol_line *n;
71 
72   if (expressionP->X_op == O_symbol
73       && expressionP->X_add_number == 0)
74     return expressionP->X_add_symbol;
75 
76   if (expressionP->X_op == O_big)
77     {
78       /* This won't work, because the actual value is stored in
79 	 generic_floating_point_number or generic_bignum, and we are
80 	 going to lose it if we haven't already.  */
81       if (expressionP->X_add_number > 0)
82 	as_bad (_("bignum invalid"));
83       else
84 	as_bad (_("floating point number invalid"));
85       zero.X_op = O_constant;
86       zero.X_add_number = 0;
87       zero.X_unsigned = 0;
88       zero.X_extrabit = 0;
89       clean_up_expression (&zero);
90       expressionP = &zero;
91     }
92 
93   /* Putting constant symbols in absolute_section rather than
94      expr_section is convenient for the old a.out code, for which
95      S_GET_SEGMENT does not always retrieve the value put in by
96      S_SET_SEGMENT.  */
97   symbolP = symbol_create (FAKE_LABEL_NAME,
98 			   (expressionP->X_op == O_constant
99 			    ? absolute_section
100 			    : expressionP->X_op == O_register
101 			      ? reg_section
102 			      : expr_section),
103 			   0, &zero_address_frag);
104   symbol_set_value_expression (symbolP, expressionP);
105 
106   if (expressionP->X_op == O_constant)
107     resolve_symbol_value (symbolP);
108 
109   n = XNEW (struct expr_symbol_line);
110   n->sym = symbolP;
111   n->file = as_where (&n->line);
112   n->next = expr_symbol_lines;
113   expr_symbol_lines = n;
114 
115   return symbolP;
116 }
117 
118 /* Return the file and line number for an expr symbol.  Return
119    non-zero if something was found, 0 if no information is known for
120    the symbol.  */
121 
122 int
123 expr_symbol_where (symbolS *sym, const char **pfile, unsigned int *pline)
124 {
125   struct expr_symbol_line *l;
126 
127   for (l = expr_symbol_lines; l != NULL; l = l->next)
128     {
129       if (l->sym == sym)
130 	{
131 	  *pfile = l->file;
132 	  *pline = l->line;
133 	  return 1;
134 	}
135     }
136 
137   return 0;
138 }
139 
140 /* Utilities for building expressions.
141    Since complex expressions are recorded as symbols for use in other
142    expressions these return a symbolS * and not an expressionS *.
143    These explicitly do not take an "add_number" argument.  */
144 /* ??? For completeness' sake one might want expr_build_symbol.
145    It would just return its argument.  */
146 
147 /* Build an expression for an unsigned constant.
148    The corresponding one for signed constants is missing because
149    there's currently no need for it.  One could add an unsigned_p flag
150    but that seems more clumsy.  */
151 
152 symbolS *
153 expr_build_uconstant (offsetT value)
154 {
155   expressionS e;
156 
157   e.X_op = O_constant;
158   e.X_add_number = value;
159   e.X_unsigned = 1;
160   e.X_extrabit = 0;
161   return make_expr_symbol (&e);
162 }
163 
164 /* Build an expression for the current location ('.').  */
165 
166 symbolS *
167 expr_build_dot (void)
168 {
169   expressionS e;
170 
171   current_location (&e);
172   return symbol_clone_if_forward_ref (make_expr_symbol (&e));
173 }
174 
175 /* Build any floating-point literal here.
176    Also build any bignum literal here.  */
177 
178 /* Seems atof_machine can backscan through generic_bignum and hit whatever
179    happens to be loaded before it in memory.  And its way too complicated
180    for me to fix right.  Thus a hack.  JF:  Just make generic_bignum bigger,
181    and never write into the early words, thus they'll always be zero.
182    I hate Dean's floating-point code.  Bleh.  */
183 LITTLENUM_TYPE generic_bignum[SIZE_OF_LARGE_NUMBER + 6];
184 
185 FLONUM_TYPE generic_floating_point_number = {
186   &generic_bignum[6],		/* low.  (JF: Was 0)  */
187   &generic_bignum[SIZE_OF_LARGE_NUMBER + 6 - 1], /* high.  JF: (added +6)  */
188   0,				/* leader.  */
189   0,				/* exponent.  */
190   0				/* sign.  */
191 };
192 
193 
194 static void
195 floating_constant (expressionS *expressionP)
196 {
197   /* input_line_pointer -> floating-point constant.  */
198   int error_code;
199 
200   error_code = atof_generic (&input_line_pointer, ".", EXP_CHARS,
201 			     &generic_floating_point_number);
202 
203   if (error_code)
204     {
205       if (error_code == ERROR_EXPONENT_OVERFLOW)
206 	{
207 	  as_bad (_("bad floating-point constant: exponent overflow"));
208 	}
209       else
210 	{
211 	  as_bad (_("bad floating-point constant: unknown error code=%d"),
212 		  error_code);
213 	}
214     }
215   expressionP->X_op = O_big;
216   /* input_line_pointer -> just after constant, which may point to
217      whitespace.  */
218   expressionP->X_add_number = -1;
219 }
220 
221 static valueT
222 generic_bignum_to_int32 (void)
223 {
224   valueT number =
225 	   ((generic_bignum[1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS)
226 	   | (generic_bignum[0] & LITTLENUM_MASK);
227   number &= 0xffffffff;
228   return number;
229 }
230 
231 #ifdef BFD64
232 static valueT
233 generic_bignum_to_int64 (void)
234 {
235   valueT number =
236     ((((((((valueT) generic_bignum[3] & LITTLENUM_MASK)
237 	  << LITTLENUM_NUMBER_OF_BITS)
238 	 | ((valueT) generic_bignum[2] & LITTLENUM_MASK))
239 	<< LITTLENUM_NUMBER_OF_BITS)
240        | ((valueT) generic_bignum[1] & LITTLENUM_MASK))
241       << LITTLENUM_NUMBER_OF_BITS)
242      | ((valueT) generic_bignum[0] & LITTLENUM_MASK));
243   return number;
244 }
245 #endif
246 
247 static void
248 integer_constant (int radix, expressionS *expressionP)
249 {
250   char *start;		/* Start of number.  */
251   char *suffix = NULL;
252   char c;
253   valueT number;	/* Offset or (absolute) value.  */
254   short int digit;	/* Value of next digit in current radix.  */
255   short int maxdig = 0;	/* Highest permitted digit value.  */
256   int too_many_digits = 0;	/* If we see >= this number of.  */
257   char *name;		/* Points to name of symbol.  */
258   symbolS *symbolP;	/* Points to symbol.  */
259 
260   int small;			/* True if fits in 32 bits.  */
261 
262   /* May be bignum, or may fit in 32 bits.  */
263   /* Most numbers fit into 32 bits, and we want this case to be fast.
264      so we pretend it will fit into 32 bits.  If, after making up a 32
265      bit number, we realise that we have scanned more digits than
266      comfortably fit into 32 bits, we re-scan the digits coding them
267      into a bignum.  For decimal and octal numbers we are
268      conservative: Some numbers may be assumed bignums when in fact
269      they do fit into 32 bits.  Numbers of any radix can have excess
270      leading zeros: We strive to recognise this and cast them back
271      into 32 bits.  We must check that the bignum really is more than
272      32 bits, and change it back to a 32-bit number if it fits.  The
273      number we are looking for is expected to be positive, but if it
274      fits into 32 bits as an unsigned number, we let it be a 32-bit
275      number.  The cavalier approach is for speed in ordinary cases.  */
276   /* This has been extended for 64 bits.  We blindly assume that if
277      you're compiling in 64-bit mode, the target is a 64-bit machine.
278      This should be cleaned up.  */
279 
280 #ifdef BFD64
281 #define valuesize 64
282 #else /* includes non-bfd case, mostly */
283 #define valuesize 32
284 #endif
285 
286   if (is_end_of_line[(unsigned char) *input_line_pointer])
287     {
288       expressionP->X_op = O_absent;
289       return;
290     }
291 
292   if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri) && radix == 0)
293     {
294       int flt = 0;
295 
296       /* In MRI mode, the number may have a suffix indicating the
297 	 radix.  For that matter, it might actually be a floating
298 	 point constant.  */
299       for (suffix = input_line_pointer; ISALNUM (*suffix); suffix++)
300 	{
301 	  if (*suffix == 'e' || *suffix == 'E')
302 	    flt = 1;
303 	}
304 
305       if (suffix == input_line_pointer)
306 	{
307 	  radix = 10;
308 	  suffix = NULL;
309 	}
310       else
311 	{
312 	  c = *--suffix;
313 	  c = TOUPPER (c);
314 	  /* If we have both NUMBERS_WITH_SUFFIX and LOCAL_LABELS_FB,
315 	     we distinguish between 'B' and 'b'.  This is the case for
316 	     Z80.  */
317 	  if ((NUMBERS_WITH_SUFFIX && LOCAL_LABELS_FB ? *suffix : c) == 'B')
318 	    radix = 2;
319 	  else if (c == 'D')
320 	    radix = 10;
321 	  else if (c == 'O' || c == 'Q')
322 	    radix = 8;
323 	  else if (c == 'H')
324 	    radix = 16;
325 	  else if (suffix[1] == '.' || c == 'E' || flt)
326 	    {
327 	      floating_constant (expressionP);
328 	      return;
329 	    }
330 	  else
331 	    {
332 	      radix = 10;
333 	      suffix = NULL;
334 	    }
335 	}
336     }
337 
338   switch (radix)
339     {
340     case 2:
341       maxdig = 2;
342       too_many_digits = valuesize + 1;
343       break;
344     case 8:
345       maxdig = radix = 8;
346       too_many_digits = (valuesize + 2) / 3 + 1;
347       break;
348     case 16:
349       maxdig = radix = 16;
350       too_many_digits = (valuesize + 3) / 4 + 1;
351       break;
352     case 10:
353       maxdig = radix = 10;
354       too_many_digits = (valuesize + 11) / 4; /* Very rough.  */
355     }
356 #undef valuesize
357   start = input_line_pointer;
358   c = *input_line_pointer++;
359   for (number = 0;
360        (digit = hex_value (c)) < maxdig;
361        c = *input_line_pointer++)
362     {
363       number = number * radix + digit;
364     }
365   /* c contains character after number.  */
366   /* input_line_pointer->char after c.  */
367   small = (input_line_pointer - start - 1) < too_many_digits;
368 
369   if (radix == 16 && c == '_')
370     {
371       /* This is literal of the form 0x333_0_12345678_1.
372 	 This example is equivalent to 0x00000333000000001234567800000001.  */
373 
374       int num_little_digits = 0;
375       int i;
376       input_line_pointer = start;	/* -> 1st digit.  */
377 
378       know (LITTLENUM_NUMBER_OF_BITS == 16);
379 
380       for (c = '_'; c == '_'; num_little_digits += 2)
381 	{
382 
383 	  /* Convert one 64-bit word.  */
384 	  int ndigit = 0;
385 	  number = 0;
386 	  for (c = *input_line_pointer++;
387 	       (digit = hex_value (c)) < maxdig;
388 	       c = *(input_line_pointer++))
389 	    {
390 	      number = number * radix + digit;
391 	      ndigit++;
392 	    }
393 
394 	  /* Check for 8 digit per word max.  */
395 	  if (ndigit > 8)
396 	    as_bad (_("a bignum with underscores may not have more than 8 hex digits in any word"));
397 
398 	  /* Add this chunk to the bignum.
399 	     Shift things down 2 little digits.  */
400 	  know (LITTLENUM_NUMBER_OF_BITS == 16);
401 	  for (i = min (num_little_digits + 1, SIZE_OF_LARGE_NUMBER - 1);
402 	       i >= 2;
403 	       i--)
404 	    generic_bignum[i] = generic_bignum[i - 2];
405 
406 	  /* Add the new digits as the least significant new ones.  */
407 	  generic_bignum[0] = number & 0xffffffff;
408 	  generic_bignum[1] = number >> 16;
409 	}
410 
411       /* Again, c is char after number, input_line_pointer->after c.  */
412 
413       if (num_little_digits > SIZE_OF_LARGE_NUMBER - 1)
414 	num_little_digits = SIZE_OF_LARGE_NUMBER - 1;
415 
416       gas_assert (num_little_digits >= 4);
417 
418       if (num_little_digits != 8)
419 	as_bad (_("a bignum with underscores must have exactly 4 words"));
420 
421       /* We might have some leading zeros.  These can be trimmed to give
422 	 us a change to fit this constant into a small number.  */
423       while (generic_bignum[num_little_digits - 1] == 0
424 	     && num_little_digits > 1)
425 	num_little_digits--;
426 
427       if (num_little_digits <= 2)
428 	{
429 	  /* will fit into 32 bits.  */
430 	  number = generic_bignum_to_int32 ();
431 	  small = 1;
432 	}
433 #ifdef BFD64
434       else if (num_little_digits <= 4)
435 	{
436 	  /* Will fit into 64 bits.  */
437 	  number = generic_bignum_to_int64 ();
438 	  small = 1;
439 	}
440 #endif
441       else
442 	{
443 	  small = 0;
444 
445 	  /* Number of littlenums in the bignum.  */
446 	  number = num_little_digits;
447 	}
448     }
449   else if (!small)
450     {
451       /* We saw a lot of digits. manufacture a bignum the hard way.  */
452       LITTLENUM_TYPE *leader;	/* -> high order littlenum of the bignum.  */
453       LITTLENUM_TYPE *pointer;	/* -> littlenum we are frobbing now.  */
454       long carry;
455 
456       leader = generic_bignum;
457       generic_bignum[0] = 0;
458       generic_bignum[1] = 0;
459       generic_bignum[2] = 0;
460       generic_bignum[3] = 0;
461       input_line_pointer = start;	/* -> 1st digit.  */
462       c = *input_line_pointer++;
463       for (; (carry = hex_value (c)) < maxdig; c = *input_line_pointer++)
464 	{
465 	  for (pointer = generic_bignum; pointer <= leader; pointer++)
466 	    {
467 	      long work;
468 
469 	      work = carry + radix * *pointer;
470 	      *pointer = work & LITTLENUM_MASK;
471 	      carry = work >> LITTLENUM_NUMBER_OF_BITS;
472 	    }
473 	  if (carry)
474 	    {
475 	      if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1)
476 		{
477 		  /* Room to grow a longer bignum.  */
478 		  *++leader = carry;
479 		}
480 	    }
481 	}
482       /* Again, c is char after number.  */
483       /* input_line_pointer -> after c.  */
484       know (LITTLENUM_NUMBER_OF_BITS == 16);
485       if (leader < generic_bignum + 2)
486 	{
487 	  /* Will fit into 32 bits.  */
488 	  number = generic_bignum_to_int32 ();
489 	  small = 1;
490 	}
491 #ifdef BFD64
492       else if (leader < generic_bignum + 4)
493 	{
494 	  /* Will fit into 64 bits.  */
495 	  number = generic_bignum_to_int64 ();
496 	  small = 1;
497 	}
498 #endif
499       else
500 	{
501 	  /* Number of littlenums in the bignum.  */
502 	  number = leader - generic_bignum + 1;
503 	}
504     }
505 
506   if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)
507       && suffix != NULL
508       && input_line_pointer - 1 == suffix)
509     c = *input_line_pointer++;
510 
511 #ifndef tc_allow_U_suffix
512 #define tc_allow_U_suffix 1
513 #endif
514   /* PR 19910: Look for, and ignore, a U suffix to the number.  */
515   if (tc_allow_U_suffix && (c == 'U' || c == 'u'))
516     c = * input_line_pointer++;
517 
518 #ifndef tc_allow_L_suffix
519 #define tc_allow_L_suffix 1
520 #endif
521   /* PR 20732: Look for, and ignore, a L or LL suffix to the number.  */
522   if (tc_allow_L_suffix)
523     while (c == 'L' || c == 'l')
524       c = * input_line_pointer++;
525 
526   if (small)
527     {
528       /* Here with number, in correct radix. c is the next char.
529 	 Note that unlike un*x, we allow "011f" "0x9f" to both mean
530 	 the same as the (conventional) "9f".
531 	 This is simply easier than checking for strict canonical
532 	 form.  Syntax sux!  */
533 
534       if (LOCAL_LABELS_FB && c == 'b')
535 	{
536 	  /* Backward ref to local label.
537 	     Because it is backward, expect it to be defined.  */
538 	  /* Construct a local label.  */
539 	  name = fb_label_name ((int) number, 0);
540 
541 	  /* Seen before, or symbol is defined: OK.  */
542 	  symbolP = symbol_find (name);
543 	  if ((symbolP != NULL) && (S_IS_DEFINED (symbolP)))
544 	    {
545 	      /* Local labels are never absolute.  Don't waste time
546 		 checking absoluteness.  */
547 	      know (SEG_NORMAL (S_GET_SEGMENT (symbolP)));
548 
549 	      expressionP->X_op = O_symbol;
550 	      expressionP->X_add_symbol = symbolP;
551 	    }
552 	  else
553 	    {
554 	      /* Either not seen or not defined.  */
555 	      /* @@ Should print out the original string instead of
556 		 the parsed number.  */
557 	      as_bad (_("backward ref to unknown label \"%d:\""),
558 		      (int) number);
559 	      expressionP->X_op = O_constant;
560 	    }
561 
562 	  expressionP->X_add_number = 0;
563 	}			/* case 'b' */
564       else if (LOCAL_LABELS_FB && c == 'f')
565 	{
566 	  /* Forward reference.  Expect symbol to be undefined or
567 	     unknown.  undefined: seen it before.  unknown: never seen
568 	     it before.
569 
570 	     Construct a local label name, then an undefined symbol.
571 	     Don't create a xseg frag for it: caller may do that.
572 	     Just return it as never seen before.  */
573 	  name = fb_label_name ((int) number, 1);
574 	  symbolP = symbol_find_or_make (name);
575 	  /* We have no need to check symbol properties.  */
576 #ifndef many_segments
577 	  /* Since "know" puts its arg into a "string", we
578 	     can't have newlines in the argument.  */
579 	  know (S_GET_SEGMENT (symbolP) == undefined_section || S_GET_SEGMENT (symbolP) == text_section || S_GET_SEGMENT (symbolP) == data_section);
580 #endif
581 	  expressionP->X_op = O_symbol;
582 	  expressionP->X_add_symbol = symbolP;
583 	  expressionP->X_add_number = 0;
584 	}			/* case 'f' */
585       else if (LOCAL_LABELS_DOLLAR && c == '$')
586 	{
587 	  /* If the dollar label is *currently* defined, then this is just
588 	     another reference to it.  If it is not *currently* defined,
589 	     then this is a fresh instantiation of that number, so create
590 	     it.  */
591 
592 	  if (dollar_label_defined ((long) number))
593 	    {
594 	      name = dollar_label_name ((long) number, 0);
595 	      symbolP = symbol_find (name);
596 	      know (symbolP != NULL);
597 	    }
598 	  else
599 	    {
600 	      name = dollar_label_name ((long) number, 1);
601 	      symbolP = symbol_find_or_make (name);
602 	    }
603 
604 	  expressionP->X_op = O_symbol;
605 	  expressionP->X_add_symbol = symbolP;
606 	  expressionP->X_add_number = 0;
607 	}			/* case '$' */
608       else
609 	{
610 	  expressionP->X_op = O_constant;
611 	  expressionP->X_add_number = number;
612 	  input_line_pointer--;	/* Restore following character.  */
613 	}			/* Really just a number.  */
614     }
615   else
616     {
617       /* Not a small number.  */
618       expressionP->X_op = O_big;
619       expressionP->X_add_number = number;	/* Number of littlenums.  */
620       input_line_pointer--;	/* -> char following number.  */
621     }
622 }
623 
624 /* Parse an MRI multi character constant.  */
625 
626 static void
627 mri_char_constant (expressionS *expressionP)
628 {
629   int i;
630 
631   if (*input_line_pointer == '\''
632       && input_line_pointer[1] != '\'')
633     {
634       expressionP->X_op = O_constant;
635       expressionP->X_add_number = 0;
636       return;
637     }
638 
639   /* In order to get the correct byte ordering, we must build the
640      number in reverse.  */
641   for (i = SIZE_OF_LARGE_NUMBER - 1; i >= 0; i--)
642     {
643       int j;
644 
645       generic_bignum[i] = 0;
646       for (j = 0; j < CHARS_PER_LITTLENUM; j++)
647 	{
648 	  if (*input_line_pointer == '\'')
649 	    {
650 	      if (input_line_pointer[1] != '\'')
651 		break;
652 	      ++input_line_pointer;
653 	    }
654 	  generic_bignum[i] <<= 8;
655 	  generic_bignum[i] += *input_line_pointer;
656 	  ++input_line_pointer;
657 	}
658 
659       if (i < SIZE_OF_LARGE_NUMBER - 1)
660 	{
661 	  /* If there is more than one littlenum, left justify the
662 	     last one to make it match the earlier ones.  If there is
663 	     only one, we can just use the value directly.  */
664 	  for (; j < CHARS_PER_LITTLENUM; j++)
665 	    generic_bignum[i] <<= 8;
666 	}
667 
668       if (*input_line_pointer == '\''
669 	  && input_line_pointer[1] != '\'')
670 	break;
671     }
672 
673   if (i < 0)
674     {
675       as_bad (_("character constant too large"));
676       i = 0;
677     }
678 
679   if (i > 0)
680     {
681       int c;
682       int j;
683 
684       c = SIZE_OF_LARGE_NUMBER - i;
685       for (j = 0; j < c; j++)
686 	generic_bignum[j] = generic_bignum[i + j];
687       i = c;
688     }
689 
690   know (LITTLENUM_NUMBER_OF_BITS == 16);
691   if (i > 2)
692     {
693       expressionP->X_op = O_big;
694       expressionP->X_add_number = i;
695     }
696   else
697     {
698       expressionP->X_op = O_constant;
699       if (i < 2)
700 	expressionP->X_add_number = generic_bignum[0] & LITTLENUM_MASK;
701       else
702 	expressionP->X_add_number =
703 	  (((generic_bignum[1] & LITTLENUM_MASK)
704 	    << LITTLENUM_NUMBER_OF_BITS)
705 	   | (generic_bignum[0] & LITTLENUM_MASK));
706     }
707 
708   /* Skip the final closing quote.  */
709   ++input_line_pointer;
710 }
711 
712 /* Return an expression representing the current location.  This
713    handles the magic symbol `.'.  */
714 
715 void
716 current_location (expressionS *expressionp)
717 {
718   if (now_seg == absolute_section)
719     {
720       expressionp->X_op = O_constant;
721       expressionp->X_add_number = abs_section_offset;
722     }
723   else
724     {
725       expressionp->X_op = O_symbol;
726       expressionp->X_add_symbol = &dot_symbol;
727       expressionp->X_add_number = 0;
728     }
729 }
730 
731 /* In:	Input_line_pointer points to 1st char of operand, which may
732 	be a space.
733 
734    Out:	An expressionS.
735 	The operand may have been empty: in this case X_op == O_absent.
736 	Input_line_pointer->(next non-blank) char after operand.  */
737 
738 static segT
739 operand (expressionS *expressionP, enum expr_mode mode)
740 {
741   char c;
742   symbolS *symbolP;	/* Points to symbol.  */
743   char *name;		/* Points to name of symbol.  */
744   segT segment;
745 
746   /* All integers are regarded as unsigned unless they are negated.
747      This is because the only thing which cares whether a number is
748      unsigned is the code in emit_expr which extends constants into
749      bignums.  It should only sign extend negative numbers, so that
750      something like ``.quad 0x80000000'' is not sign extended even
751      though it appears negative if valueT is 32 bits.  */
752   expressionP->X_unsigned = 1;
753   expressionP->X_extrabit = 0;
754 
755   /* Digits, assume it is a bignum.  */
756 
757   SKIP_WHITESPACE ();		/* Leading whitespace is part of operand.  */
758   c = *input_line_pointer++;	/* input_line_pointer -> past char in c.  */
759 
760   if (is_end_of_line[(unsigned char) c])
761     goto eol;
762 
763   switch (c)
764     {
765     case '1':
766     case '2':
767     case '3':
768     case '4':
769     case '5':
770     case '6':
771     case '7':
772     case '8':
773     case '9':
774       input_line_pointer--;
775 
776       integer_constant ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)
777 			? 0 : 10,
778 			expressionP);
779       break;
780 
781 #ifdef LITERAL_PREFIXDOLLAR_HEX
782     case '$':
783       /* $L is the start of a local label, not a hex constant.  */
784       if (* input_line_pointer == 'L')
785       goto isname;
786       integer_constant (16, expressionP);
787       break;
788 #endif
789 
790 #ifdef LITERAL_PREFIXPERCENT_BIN
791     case '%':
792       integer_constant (2, expressionP);
793       break;
794 #endif
795 
796     case '0':
797       /* Non-decimal radix.  */
798 
799       if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)
800 	{
801 	  char *s;
802 
803 	  /* Check for a hex or float constant.  */
804 	  for (s = input_line_pointer; hex_p (*s); s++)
805 	    ;
806 	  if (*s == 'h' || *s == 'H' || *input_line_pointer == '.')
807 	    {
808 	      --input_line_pointer;
809 	      integer_constant (0, expressionP);
810 	      break;
811 	    }
812 	}
813       c = *input_line_pointer;
814       switch (c)
815 	{
816 	case 'o':
817 	case 'O':
818 	case 'q':
819 	case 'Q':
820 	case '8':
821 	case '9':
822 	  if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)
823 	    {
824 	      integer_constant (0, expressionP);
825 	      break;
826 	    }
827 	  /* Fall through.  */
828 	default:
829 	default_case:
830 	  if (c && strchr (FLT_CHARS, c))
831 	    {
832 	      input_line_pointer++;
833 	      floating_constant (expressionP);
834 	      expressionP->X_add_number = - TOLOWER (c);
835 	    }
836 	  else
837 	    {
838 	      /* The string was only zero.  */
839 	      expressionP->X_op = O_constant;
840 	      expressionP->X_add_number = 0;
841 	    }
842 
843 	  break;
844 
845 	case 'x':
846 	case 'X':
847 	  if (flag_m68k_mri)
848 	    goto default_case;
849 	  input_line_pointer++;
850 	  integer_constant (16, expressionP);
851 	  break;
852 
853 	case 'b':
854 	  if (LOCAL_LABELS_FB && !flag_m68k_mri
855 	      && input_line_pointer[1] != '0'
856 	      && input_line_pointer[1] != '1')
857 	    {
858 	      /* Parse this as a back reference to label 0.  */
859 	      input_line_pointer--;
860 	      integer_constant (10, expressionP);
861 	      break;
862 	    }
863 	  /* Otherwise, parse this as a binary number.  */
864 	  /* Fall through.  */
865 	case 'B':
866 	  if (input_line_pointer[1] == '0'
867 	      || input_line_pointer[1] == '1')
868 	    {
869 	      input_line_pointer++;
870 	      integer_constant (2, expressionP);
871 	      break;
872 	    }
873 	  if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)
874 	    input_line_pointer++;
875 	  goto default_case;
876 
877 	case '0':
878 	case '1':
879 	case '2':
880 	case '3':
881 	case '4':
882 	case '5':
883 	case '6':
884 	case '7':
885 	  integer_constant ((flag_m68k_mri || NUMBERS_WITH_SUFFIX)
886 			    ? 0 : 8,
887 			    expressionP);
888 	  break;
889 
890 	case 'f':
891 	  if (LOCAL_LABELS_FB)
892 	    {
893 	      int is_label = 1;
894 
895 	      /* If it says "0f" and it could possibly be a floating point
896 		 number, make it one.  Otherwise, make it a local label,
897 		 and try to deal with parsing the rest later.  */
898 	      if (!is_end_of_line[(unsigned char) input_line_pointer[1]]
899 		  && strchr (FLT_CHARS, 'f') != NULL)
900 		{
901 		  char *cp = input_line_pointer + 1;
902 
903 		  atof_generic (&cp, ".", EXP_CHARS,
904 				&generic_floating_point_number);
905 
906 		  /* Was nothing parsed, or does it look like an
907 		     expression?  */
908 		  is_label = (cp == input_line_pointer + 1
909 			      || (cp == input_line_pointer + 2
910 				  && (cp[-1] == '-' || cp[-1] == '+'))
911 			      || *cp == 'f'
912 			      || *cp == 'b');
913 		}
914 	      if (is_label)
915 		{
916 		  input_line_pointer--;
917 		  integer_constant (10, expressionP);
918 		  break;
919 		}
920 	    }
921 	  /* Fall through.  */
922 
923 	case 'd':
924 	case 'D':
925 	  if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)
926 	    {
927 	      integer_constant (0, expressionP);
928 	      break;
929 	    }
930 	  /* Fall through.  */
931 	case 'F':
932 	case 'r':
933 	case 'e':
934 	case 'E':
935 	case 'g':
936 	case 'G':
937 	  input_line_pointer++;
938 	  floating_constant (expressionP);
939 	  expressionP->X_add_number = - TOLOWER (c);
940 	  break;
941 
942 	case '$':
943 	  if (LOCAL_LABELS_DOLLAR)
944 	    {
945 	      integer_constant (10, expressionP);
946 	      break;
947 	    }
948 	  else
949 	    goto default_case;
950 	}
951 
952       break;
953 
954 #ifndef NEED_INDEX_OPERATOR
955     case '[':
956 # ifdef md_need_index_operator
957       if (md_need_index_operator())
958 	goto de_fault;
959 # endif
960 #endif
961       /* Fall through.  */
962     case '(':
963       /* Didn't begin with digit & not a name.  */
964       segment = expr (0, expressionP, mode);
965       /* expression () will pass trailing whitespace.  */
966       if ((c == '(' && *input_line_pointer != ')')
967 	  || (c == '[' && *input_line_pointer != ']'))
968 	{
969 	  if (* input_line_pointer)
970 	    as_bad (_("found '%c', expected: '%c'"),
971 		    * input_line_pointer, c == '(' ? ')' : ']');
972 	  else
973 	    as_bad (_("missing '%c'"), c == '(' ? ')' : ']');
974 	}
975       else
976 	input_line_pointer++;
977       SKIP_WHITESPACE ();
978       /* Here with input_line_pointer -> char after "(...)".  */
979       return segment;
980 
981 #ifdef TC_M68K
982     case 'E':
983       if (! flag_m68k_mri || *input_line_pointer != '\'')
984 	goto de_fault;
985       as_bad (_("EBCDIC constants are not supported"));
986       /* Fall through.  */
987     case 'A':
988       if (! flag_m68k_mri || *input_line_pointer != '\'')
989 	goto de_fault;
990       ++input_line_pointer;
991 #endif
992       /* Fall through.  */
993     case '\'':
994       if (! flag_m68k_mri)
995 	{
996 	  /* Warning: to conform to other people's assemblers NO
997 	     ESCAPEMENT is permitted for a single quote.  The next
998 	     character, parity errors and all, is taken as the value
999 	     of the operand.  VERY KINKY.  */
1000 	  expressionP->X_op = O_constant;
1001 	  expressionP->X_add_number = *input_line_pointer++;
1002 	  break;
1003 	}
1004 
1005       mri_char_constant (expressionP);
1006       break;
1007 
1008 #ifdef TC_M68K
1009     case '"':
1010       /* Double quote is the bitwise not operator in MRI mode.  */
1011       if (! flag_m68k_mri)
1012 	goto de_fault;
1013 #endif
1014       /* Fall through.  */
1015     case '~':
1016       /* '~' is permitted to start a label on the Delta.  */
1017       if (is_name_beginner (c))
1018 	goto isname;
1019       /* Fall through.  */
1020     case '!':
1021     case '-':
1022     case '+':
1023       {
1024 #ifdef md_operator
1025       unary:
1026 #endif
1027 	operand (expressionP, mode);
1028 	if (expressionP->X_op == O_constant)
1029 	  {
1030 	    /* input_line_pointer -> char after operand.  */
1031 	    if (c == '-')
1032 	      {
1033 		expressionP->X_add_number
1034 		  = - (addressT) expressionP->X_add_number;
1035 		/* Notice: '-' may overflow: no warning is given.
1036 		   This is compatible with other people's
1037 		   assemblers.  Sigh.  */
1038 		expressionP->X_unsigned = 0;
1039 		if (expressionP->X_add_number)
1040 		  expressionP->X_extrabit ^= 1;
1041 	      }
1042 	    else if (c == '~' || c == '"')
1043 	      expressionP->X_add_number = ~ expressionP->X_add_number;
1044 	    else if (c == '!')
1045 	      expressionP->X_add_number = ! expressionP->X_add_number;
1046 	  }
1047 	else if (expressionP->X_op == O_big
1048 		 && expressionP->X_add_number <= 0
1049 		 && c == '-'
1050 		 && (generic_floating_point_number.sign == '+'
1051 		     || generic_floating_point_number.sign == 'P'))
1052 	  {
1053 	    /* Negative flonum (eg, -1.000e0).  */
1054 	    if (generic_floating_point_number.sign == '+')
1055 	      generic_floating_point_number.sign = '-';
1056 	    else
1057 	      generic_floating_point_number.sign = 'N';
1058 	  }
1059 	else if (expressionP->X_op == O_big
1060 		 && expressionP->X_add_number > 0)
1061 	  {
1062 	    int i;
1063 
1064 	    if (c == '~' || c == '-')
1065 	      {
1066 		for (i = 0; i < expressionP->X_add_number; ++i)
1067 		  generic_bignum[i] = ~generic_bignum[i];
1068 
1069 		/* Extend the bignum to at least the size of .octa.  */
1070 		if (expressionP->X_add_number < SIZE_OF_LARGE_NUMBER)
1071 		  {
1072 		    expressionP->X_add_number = SIZE_OF_LARGE_NUMBER;
1073 		    for (; i < expressionP->X_add_number; ++i)
1074 		      generic_bignum[i] = ~(LITTLENUM_TYPE) 0;
1075 		  }
1076 
1077 		if (c == '-')
1078 		  for (i = 0; i < expressionP->X_add_number; ++i)
1079 		    {
1080 		      generic_bignum[i] += 1;
1081 		      if (generic_bignum[i])
1082 			break;
1083 		    }
1084 	      }
1085 	    else if (c == '!')
1086 	      {
1087 		for (i = 0; i < expressionP->X_add_number; ++i)
1088 		  if (generic_bignum[i] != 0)
1089 		    break;
1090 		expressionP->X_add_number = i >= expressionP->X_add_number;
1091 		expressionP->X_op = O_constant;
1092 		expressionP->X_unsigned = 1;
1093 		expressionP->X_extrabit = 0;
1094 	      }
1095 	  }
1096 	else if (expressionP->X_op != O_illegal
1097 		 && expressionP->X_op != O_absent)
1098 	  {
1099 	    if (c != '+')
1100 	      {
1101 		expressionP->X_add_symbol = make_expr_symbol (expressionP);
1102 		if (c == '-')
1103 		  expressionP->X_op = O_uminus;
1104 		else if (c == '~' || c == '"')
1105 		  expressionP->X_op = O_bit_not;
1106 		else
1107 		  expressionP->X_op = O_logical_not;
1108 		expressionP->X_add_number = 0;
1109 	      }
1110 	  }
1111 	else
1112 	  as_warn (_("Unary operator %c ignored because bad operand follows"),
1113 		   c);
1114       }
1115       break;
1116 
1117 #if defined (DOLLAR_DOT) || defined (TC_M68K)
1118     case '$':
1119       /* '$' is the program counter when in MRI mode, or when
1120 	 DOLLAR_DOT is defined.  */
1121 #ifndef DOLLAR_DOT
1122       if (! flag_m68k_mri)
1123 	goto de_fault;
1124 #endif
1125       if (DOLLAR_AMBIGU && hex_p (*input_line_pointer))
1126 	{
1127 	  /* In MRI mode and on Z80, '$' is also used as the prefix
1128 	     for a hexadecimal constant.  */
1129 	  integer_constant (16, expressionP);
1130 	  break;
1131 	}
1132 
1133       if (is_part_of_name (*input_line_pointer))
1134 	goto isname;
1135 
1136       current_location (expressionP);
1137       break;
1138 #endif
1139 
1140     case '.':
1141       if (!is_part_of_name (*input_line_pointer))
1142 	{
1143 	  current_location (expressionP);
1144 	  break;
1145 	}
1146       else if ((strncasecmp (input_line_pointer, "startof.", 8) == 0
1147 		&& ! is_part_of_name (input_line_pointer[8]))
1148 	       || (strncasecmp (input_line_pointer, "sizeof.", 7) == 0
1149 		   && ! is_part_of_name (input_line_pointer[7])))
1150 	{
1151 	  int start;
1152 
1153 	  start = (input_line_pointer[1] == 't'
1154 		   || input_line_pointer[1] == 'T');
1155 	  input_line_pointer += start ? 8 : 7;
1156 	  SKIP_WHITESPACE ();
1157 
1158 	  /* Cover for the as_bad () invocations below.  */
1159 	  expressionP->X_op = O_absent;
1160 
1161 	  if (*input_line_pointer != '(')
1162 	    as_bad (_("syntax error in .startof. or .sizeof."));
1163 	  else
1164 	    {
1165 	      char *buf;
1166 
1167 	      ++input_line_pointer;
1168 	      SKIP_WHITESPACE ();
1169 	      c = get_symbol_name (& name);
1170 	      if (! *name)
1171 		{
1172 		  as_bad (_("expected symbol name"));
1173 		  (void) restore_line_pointer (c);
1174 		  if (c != ')')
1175 		    ignore_rest_of_line ();
1176 		  else
1177 		    ++input_line_pointer;
1178 		  break;
1179 		}
1180 
1181 	      buf = concat (start ? ".startof." : ".sizeof.", name,
1182 			    (char *) NULL);
1183 	      symbolP = symbol_make (buf);
1184 	      free (buf);
1185 
1186 	      expressionP->X_op = O_symbol;
1187 	      expressionP->X_add_symbol = symbolP;
1188 	      expressionP->X_add_number = 0;
1189 
1190 	      *input_line_pointer = c;
1191 	      SKIP_WHITESPACE_AFTER_NAME ();
1192 	      if (*input_line_pointer != ')')
1193 		as_bad (_("syntax error in .startof. or .sizeof."));
1194 	      else
1195 		++input_line_pointer;
1196 	    }
1197 	  break;
1198 	}
1199       else
1200 	{
1201 	  goto isname;
1202 	}
1203 
1204     case ',':
1205     eol:
1206       /* Can't imagine any other kind of operand.  */
1207       expressionP->X_op = O_absent;
1208       input_line_pointer--;
1209       break;
1210 
1211 #ifdef TC_M68K
1212     case '%':
1213       if (! flag_m68k_mri)
1214 	goto de_fault;
1215       integer_constant (2, expressionP);
1216       break;
1217 
1218     case '@':
1219       if (! flag_m68k_mri)
1220 	goto de_fault;
1221       integer_constant (8, expressionP);
1222       break;
1223 
1224     case ':':
1225       if (! flag_m68k_mri)
1226 	goto de_fault;
1227 
1228       /* In MRI mode, this is a floating point constant represented
1229 	 using hexadecimal digits.  */
1230 
1231       ++input_line_pointer;
1232       integer_constant (16, expressionP);
1233       break;
1234 
1235     case '*':
1236       if (! flag_m68k_mri || is_part_of_name (*input_line_pointer))
1237 	goto de_fault;
1238 
1239       current_location (expressionP);
1240       break;
1241 #endif
1242 
1243     default:
1244 #if defined(md_need_index_operator) || defined(TC_M68K)
1245     de_fault:
1246 #endif
1247       if (is_name_beginner (c) || c == '"')	/* Here if did not begin with a digit.  */
1248 	{
1249 	  /* Identifier begins here.
1250 	     This is kludged for speed, so code is repeated.  */
1251 	isname:
1252 	  -- input_line_pointer;
1253 	  c = get_symbol_name (&name);
1254 
1255 #ifdef md_operator
1256 	  {
1257 	    operatorT op = md_operator (name, 1, &c);
1258 
1259 	    switch (op)
1260 	      {
1261 	      case O_uminus:
1262 		restore_line_pointer (c);
1263 		c = '-';
1264 		goto unary;
1265 	      case O_bit_not:
1266 		restore_line_pointer (c);
1267 		c = '~';
1268 		goto unary;
1269 	      case O_logical_not:
1270 		restore_line_pointer (c);
1271 		c = '!';
1272 		goto unary;
1273 	      case O_illegal:
1274 		as_bad (_("invalid use of operator \"%s\""), name);
1275 		break;
1276 	      default:
1277 		break;
1278 	      }
1279 
1280 	    if (op != O_absent && op != O_illegal)
1281 	      {
1282 		restore_line_pointer (c);
1283 		expr (9, expressionP, mode);
1284 		expressionP->X_add_symbol = make_expr_symbol (expressionP);
1285 		expressionP->X_op_symbol = NULL;
1286 		expressionP->X_add_number = 0;
1287 		expressionP->X_op = op;
1288 		break;
1289 	      }
1290 	  }
1291 #endif
1292 
1293 #ifdef md_parse_name
1294 	  /* This is a hook for the backend to parse certain names
1295 	     specially in certain contexts.  If a name always has a
1296 	     specific value, it can often be handled by simply
1297 	     entering it in the symbol table.  */
1298 	  if (md_parse_name (name, expressionP, mode, &c))
1299 	    {
1300 	      restore_line_pointer (c);
1301 	      break;
1302 	    }
1303 #endif
1304 
1305 	  symbolP = symbol_find_or_make (name);
1306 
1307 	  /* If we have an absolute symbol or a reg, then we know its
1308 	     value now.  */
1309 	  segment = S_GET_SEGMENT (symbolP);
1310 	  if (mode != expr_defer
1311 	      && segment == absolute_section
1312 	      && !S_FORCE_RELOC (symbolP, 0))
1313 	    {
1314 	      expressionP->X_op = O_constant;
1315 	      expressionP->X_add_number = S_GET_VALUE (symbolP);
1316 	    }
1317 	  else if (mode != expr_defer && segment == reg_section)
1318 	    {
1319 	      expressionP->X_op = O_register;
1320 	      expressionP->X_add_number = S_GET_VALUE (symbolP);
1321 	    }
1322 	  else
1323 	    {
1324 	      expressionP->X_op = O_symbol;
1325 	      expressionP->X_add_symbol = symbolP;
1326 	      expressionP->X_add_number = 0;
1327 	    }
1328 
1329 	  restore_line_pointer (c);
1330 	}
1331       else
1332 	{
1333 	  /* Let the target try to parse it.  Success is indicated by changing
1334 	     the X_op field to something other than O_absent and pointing
1335 	     input_line_pointer past the expression.  If it can't parse the
1336 	     expression, X_op and input_line_pointer should be unchanged.  */
1337 	  expressionP->X_op = O_absent;
1338 	  --input_line_pointer;
1339 	  md_operand (expressionP);
1340 	  if (expressionP->X_op == O_absent)
1341 	    {
1342 	      ++input_line_pointer;
1343 	      as_bad (_("bad expression"));
1344 	      expressionP->X_op = O_constant;
1345 	      expressionP->X_add_number = 0;
1346 	    }
1347 	}
1348       break;
1349     }
1350 
1351   /* It is more 'efficient' to clean up the expressionS when they are
1352      created.  Doing it here saves lines of code.  */
1353   clean_up_expression (expressionP);
1354   SKIP_ALL_WHITESPACE ();		/* -> 1st char after operand.  */
1355   know (*input_line_pointer != ' ');
1356 
1357   /* The PA port needs this information.  */
1358   if (expressionP->X_add_symbol)
1359     symbol_mark_used (expressionP->X_add_symbol);
1360 
1361   if (mode != expr_defer)
1362     {
1363       expressionP->X_add_symbol
1364 	= symbol_clone_if_forward_ref (expressionP->X_add_symbol);
1365       expressionP->X_op_symbol
1366 	= symbol_clone_if_forward_ref (expressionP->X_op_symbol);
1367     }
1368 
1369   switch (expressionP->X_op)
1370     {
1371     default:
1372       return absolute_section;
1373     case O_symbol:
1374       return S_GET_SEGMENT (expressionP->X_add_symbol);
1375     case O_register:
1376       return reg_section;
1377     }
1378 }
1379 
1380 /* Internal.  Simplify a struct expression for use by expr ().  */
1381 
1382 /* In:	address of an expressionS.
1383 	The X_op field of the expressionS may only take certain values.
1384 	Elsewise we waste time special-case testing. Sigh. Ditto SEG_ABSENT.
1385 
1386    Out:	expressionS may have been modified:
1387 	Unused fields zeroed to help expr ().  */
1388 
1389 static void
1390 clean_up_expression (expressionS *expressionP)
1391 {
1392   switch (expressionP->X_op)
1393     {
1394     case O_illegal:
1395     case O_absent:
1396       expressionP->X_add_number = 0;
1397       /* Fall through.  */
1398     case O_big:
1399     case O_constant:
1400     case O_register:
1401       expressionP->X_add_symbol = NULL;
1402       /* Fall through.  */
1403     case O_symbol:
1404     case O_uminus:
1405     case O_bit_not:
1406       expressionP->X_op_symbol = NULL;
1407       break;
1408     default:
1409       break;
1410     }
1411 }
1412 
1413 /* Expression parser.  */
1414 
1415 /* We allow an empty expression, and just assume (absolute,0) silently.
1416    Unary operators and parenthetical expressions are treated as operands.
1417    As usual, Q==quantity==operand, O==operator, X==expression mnemonics.
1418 
1419    We used to do an aho/ullman shift-reduce parser, but the logic got so
1420    warped that I flushed it and wrote a recursive-descent parser instead.
1421    Now things are stable, would anybody like to write a fast parser?
1422    Most expressions are either register (which does not even reach here)
1423    or 1 symbol. Then "symbol+constant" and "symbol-symbol" are common.
1424    So I guess it doesn't really matter how inefficient more complex expressions
1425    are parsed.
1426 
1427    After expr(RANK,resultP) input_line_pointer->operator of rank <= RANK.
1428    Also, we have consumed any leading or trailing spaces (operand does that)
1429    and done all intervening operators.
1430 
1431    This returns the segment of the result, which will be
1432    absolute_section or the segment of a symbol.  */
1433 
1434 #undef __
1435 #define __ O_illegal
1436 #ifndef O_SINGLE_EQ
1437 #define O_SINGLE_EQ O_illegal
1438 #endif
1439 
1440 /* Maps ASCII -> operators.  */
1441 static const operatorT op_encoding[256] = {
1442   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1443   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1444 
1445   __, O_bit_or_not, __, __, __, O_modulus, O_bit_and, __,
1446   __, __, O_multiply, O_add, __, O_subtract, __, O_divide,
1447   __, __, __, __, __, __, __, __,
1448   __, __, __, __, O_lt, O_SINGLE_EQ, O_gt, __,
1449   __, __, __, __, __, __, __, __,
1450   __, __, __, __, __, __, __, __,
1451   __, __, __, __, __, __, __, __,
1452   __, __, __,
1453 #ifdef NEED_INDEX_OPERATOR
1454   O_index,
1455 #else
1456   __,
1457 #endif
1458   __, __, O_bit_exclusive_or, __,
1459   __, __, __, __, __, __, __, __,
1460   __, __, __, __, __, __, __, __,
1461   __, __, __, __, __, __, __, __,
1462   __, __, __, __, O_bit_inclusive_or, __, __, __,
1463 
1464   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1465   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1466   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1467   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1468   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1469   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1470   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
1471   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __
1472 };
1473 
1474 /* Rank	Examples
1475    0	operand, (expression)
1476    1	||
1477    2	&&
1478    3	== <> < <= >= >
1479    4	+ -
1480    5	used for * / % in MRI mode
1481    6	& ^ ! |
1482    7	* / % << >>
1483    8	unary - unary ~
1484 */
1485 static operator_rankT op_rank[O_max] = {
1486   0,	/* O_illegal */
1487   0,	/* O_absent */
1488   0,	/* O_constant */
1489   0,	/* O_symbol */
1490   0,	/* O_symbol_rva */
1491   0,	/* O_register */
1492   0,	/* O_big */
1493   9,	/* O_uminus */
1494   9,	/* O_bit_not */
1495   9,	/* O_logical_not */
1496   8,	/* O_multiply */
1497   8,	/* O_divide */
1498   8,	/* O_modulus */
1499   8,	/* O_left_shift */
1500   8,	/* O_right_shift */
1501   7,	/* O_bit_inclusive_or */
1502   7,	/* O_bit_or_not */
1503   7,	/* O_bit_exclusive_or */
1504   7,	/* O_bit_and */
1505   5,	/* O_add */
1506   5,	/* O_subtract */
1507   4,	/* O_eq */
1508   4,	/* O_ne */
1509   4,	/* O_lt */
1510   4,	/* O_le */
1511   4,	/* O_ge */
1512   4,	/* O_gt */
1513   3,	/* O_logical_and */
1514   2,	/* O_logical_or */
1515   1,	/* O_index */
1516 };
1517 
1518 /* Unfortunately, in MRI mode for the m68k, multiplication and
1519    division have lower precedence than the bit wise operators.  This
1520    function sets the operator precedences correctly for the current
1521    mode.  Also, MRI uses a different bit_not operator, and this fixes
1522    that as well.  */
1523 
1524 #define STANDARD_MUL_PRECEDENCE 8
1525 #define MRI_MUL_PRECEDENCE 6
1526 
1527 void
1528 expr_set_precedence (void)
1529 {
1530   if (flag_m68k_mri)
1531     {
1532       op_rank[O_multiply] = MRI_MUL_PRECEDENCE;
1533       op_rank[O_divide] = MRI_MUL_PRECEDENCE;
1534       op_rank[O_modulus] = MRI_MUL_PRECEDENCE;
1535     }
1536   else
1537     {
1538       op_rank[O_multiply] = STANDARD_MUL_PRECEDENCE;
1539       op_rank[O_divide] = STANDARD_MUL_PRECEDENCE;
1540       op_rank[O_modulus] = STANDARD_MUL_PRECEDENCE;
1541     }
1542 }
1543 
1544 void
1545 expr_set_rank (operatorT op, operator_rankT rank)
1546 {
1547   gas_assert (op >= O_md1 && op < ARRAY_SIZE (op_rank));
1548   op_rank[op] = rank;
1549 }
1550 
1551 /* Initialize the expression parser.  */
1552 
1553 void
1554 expr_begin (void)
1555 {
1556   expr_set_precedence ();
1557 
1558   /* Verify that X_op field is wide enough.  */
1559   {
1560     expressionS e;
1561     e.X_op = O_max;
1562     gas_assert (e.X_op == O_max);
1563   }
1564 }
1565 
1566 /* Return the encoding for the operator at INPUT_LINE_POINTER, and
1567    sets NUM_CHARS to the number of characters in the operator.
1568    Does not advance INPUT_LINE_POINTER.  */
1569 
1570 static inline operatorT
1571 operatorf (int *num_chars)
1572 {
1573   int c;
1574   operatorT ret;
1575 
1576   c = *input_line_pointer & 0xff;
1577   *num_chars = 1;
1578 
1579   if (is_end_of_line[c])
1580     return O_illegal;
1581 
1582 #ifdef md_operator
1583   if (is_name_beginner (c))
1584     {
1585       char *name;
1586       char ec = get_symbol_name (& name);
1587 
1588       ret = md_operator (name, 2, &ec);
1589       switch (ret)
1590 	{
1591 	case O_absent:
1592 	  *input_line_pointer = ec;
1593 	  input_line_pointer = name;
1594 	  break;
1595 	case O_uminus:
1596 	case O_bit_not:
1597 	case O_logical_not:
1598 	  as_bad (_("invalid use of operator \"%s\""), name);
1599 	  ret = O_illegal;
1600 	  /* FALLTHROUGH */
1601 	default:
1602 	  *input_line_pointer = ec;
1603 	  *num_chars = input_line_pointer - name;
1604 	  input_line_pointer = name;
1605 	  return ret;
1606 	}
1607     }
1608 #endif
1609 
1610   switch (c)
1611     {
1612     default:
1613       ret = op_encoding[c];
1614 #ifdef md_operator
1615       if (ret == O_illegal)
1616 	{
1617 	  char *start = input_line_pointer;
1618 
1619 	  ret = md_operator (NULL, 2, NULL);
1620 	  if (ret != O_illegal)
1621 	    *num_chars = input_line_pointer - start;
1622 	  input_line_pointer = start;
1623 	}
1624 #endif
1625       return ret;
1626 
1627     case '+':
1628     case '-':
1629       return op_encoding[c];
1630 
1631     case '<':
1632       switch (input_line_pointer[1])
1633 	{
1634 	default:
1635 	  return op_encoding[c];
1636 	case '<':
1637 	  ret = O_left_shift;
1638 	  break;
1639 	case '>':
1640 	  ret = O_ne;
1641 	  break;
1642 	case '=':
1643 	  ret = O_le;
1644 	  break;
1645 	}
1646       *num_chars = 2;
1647       return ret;
1648 
1649     case '=':
1650       if (input_line_pointer[1] != '=')
1651 	return op_encoding[c];
1652 
1653       *num_chars = 2;
1654       return O_eq;
1655 
1656     case '>':
1657       switch (input_line_pointer[1])
1658 	{
1659 	default:
1660 	  return op_encoding[c];
1661 	case '>':
1662 	  ret = O_right_shift;
1663 	  break;
1664 	case '=':
1665 	  ret = O_ge;
1666 	  break;
1667 	}
1668       *num_chars = 2;
1669       return ret;
1670 
1671     case '!':
1672       switch (input_line_pointer[1])
1673 	{
1674 	case '!':
1675 	  /* We accept !! as equivalent to ^ for MRI compatibility. */
1676 	  *num_chars = 2;
1677 	  return O_bit_exclusive_or;
1678 	case '=':
1679 	  /* We accept != as equivalent to <>.  */
1680 	  *num_chars = 2;
1681 	  return O_ne;
1682 	default:
1683 	  if (flag_m68k_mri)
1684 	    return O_bit_inclusive_or;
1685 	  return op_encoding[c];
1686 	}
1687 
1688     case '|':
1689       if (input_line_pointer[1] != '|')
1690 	return op_encoding[c];
1691 
1692       *num_chars = 2;
1693       return O_logical_or;
1694 
1695     case '&':
1696       if (input_line_pointer[1] != '&')
1697 	return op_encoding[c];
1698 
1699       *num_chars = 2;
1700       return O_logical_and;
1701     }
1702 
1703   /* NOTREACHED  */
1704 }
1705 
1706 /* Implement "word-size + 1 bit" addition for
1707    {resultP->X_extrabit:resultP->X_add_number} + {rhs_highbit:amount}.  This
1708    is used so that the full range of unsigned word values and the full range of
1709    signed word values can be represented in an O_constant expression, which is
1710    useful e.g. for .sleb128 directives.  */
1711 
1712 void
1713 add_to_result (expressionS *resultP, offsetT amount, int rhs_highbit)
1714 {
1715   valueT ures = resultP->X_add_number;
1716   valueT uamount = amount;
1717 
1718   resultP->X_add_number += amount;
1719 
1720   resultP->X_extrabit ^= rhs_highbit;
1721 
1722   if (ures + uamount < ures)
1723     resultP->X_extrabit ^= 1;
1724 }
1725 
1726 /* Similarly, for subtraction.  */
1727 
1728 void
1729 subtract_from_result (expressionS *resultP, offsetT amount, int rhs_highbit)
1730 {
1731   valueT ures = resultP->X_add_number;
1732   valueT uamount = amount;
1733 
1734   resultP->X_add_number -= amount;
1735 
1736   resultP->X_extrabit ^= rhs_highbit;
1737 
1738   if (ures < uamount)
1739     resultP->X_extrabit ^= 1;
1740 }
1741 
1742 /* Parse an expression.  */
1743 
1744 segT
1745 expr (int rankarg,		/* Larger # is higher rank.  */
1746       expressionS *resultP,	/* Deliver result here.  */
1747       enum expr_mode mode	/* Controls behavior.  */)
1748 {
1749   operator_rankT rank = (operator_rankT) rankarg;
1750   segT retval;
1751   expressionS right;
1752   operatorT op_left;
1753   operatorT op_right;
1754   int op_chars;
1755 
1756   know (rankarg >= 0);
1757 
1758   /* Save the value of dot for the fixup code.  */
1759   if (rank == 0)
1760     {
1761       dot_value = frag_now_fix ();
1762       dot_frag = frag_now;
1763     }
1764 
1765   retval = operand (resultP, mode);
1766 
1767   /* operand () gobbles spaces.  */
1768   know (*input_line_pointer != ' ');
1769 
1770   op_left = operatorf (&op_chars);
1771   while (op_left != O_illegal && op_rank[(int) op_left] > rank)
1772     {
1773       segT rightseg;
1774       offsetT frag_off;
1775 
1776       input_line_pointer += op_chars;	/* -> after operator.  */
1777 
1778       right.X_md = 0;
1779       rightseg = expr (op_rank[(int) op_left], &right, mode);
1780       if (right.X_op == O_absent)
1781 	{
1782 	  as_warn (_("missing operand; zero assumed"));
1783 	  right.X_op = O_constant;
1784 	  right.X_add_number = 0;
1785 	  right.X_add_symbol = NULL;
1786 	  right.X_op_symbol = NULL;
1787 	}
1788 
1789       know (*input_line_pointer != ' ');
1790 
1791       if (op_left == O_index)
1792 	{
1793 	  if (*input_line_pointer != ']')
1794 	    as_bad ("missing right bracket");
1795 	  else
1796 	    {
1797 	      ++input_line_pointer;
1798 	      SKIP_WHITESPACE ();
1799 	    }
1800 	}
1801 
1802       op_right = operatorf (&op_chars);
1803 
1804       know (op_right == O_illegal || op_left == O_index
1805 	    || op_rank[(int) op_right] <= op_rank[(int) op_left]);
1806       know ((int) op_left >= (int) O_multiply);
1807 #ifndef md_operator
1808       know ((int) op_left <= (int) O_index);
1809 #else
1810       know ((int) op_left < (int) O_max);
1811 #endif
1812 
1813       /* input_line_pointer->after right-hand quantity.  */
1814       /* left-hand quantity in resultP.  */
1815       /* right-hand quantity in right.  */
1816       /* operator in op_left.  */
1817 
1818       if (resultP->X_op == O_big)
1819 	{
1820 	  if (resultP->X_add_number > 0)
1821 	    as_warn (_("left operand is a bignum; integer 0 assumed"));
1822 	  else
1823 	    as_warn (_("left operand is a float; integer 0 assumed"));
1824 	  resultP->X_op = O_constant;
1825 	  resultP->X_add_number = 0;
1826 	  resultP->X_add_symbol = NULL;
1827 	  resultP->X_op_symbol = NULL;
1828 	}
1829       if (right.X_op == O_big)
1830 	{
1831 	  if (right.X_add_number > 0)
1832 	    as_warn (_("right operand is a bignum; integer 0 assumed"));
1833 	  else
1834 	    as_warn (_("right operand is a float; integer 0 assumed"));
1835 	  right.X_op = O_constant;
1836 	  right.X_add_number = 0;
1837 	  right.X_add_symbol = NULL;
1838 	  right.X_op_symbol = NULL;
1839 	}
1840 
1841       /* Optimize common cases.  */
1842 #ifdef md_optimize_expr
1843       if (md_optimize_expr (resultP, op_left, &right))
1844 	{
1845 	  /* Skip.  */
1846 	  ;
1847 	}
1848       else
1849 #endif
1850 #ifndef md_register_arithmetic
1851 # define md_register_arithmetic 1
1852 #endif
1853       if (op_left == O_add && right.X_op == O_constant
1854 	  && (md_register_arithmetic || resultP->X_op != O_register))
1855 	{
1856 	  /* X + constant.  */
1857 	  add_to_result (resultP, right.X_add_number, right.X_extrabit);
1858 	}
1859       /* This case comes up in PIC code.  */
1860       else if (op_left == O_subtract
1861 	       && right.X_op == O_symbol
1862 	       && resultP->X_op == O_symbol
1863 	       && retval == rightseg
1864 #ifdef md_allow_local_subtract
1865 	       && md_allow_local_subtract (resultP, & right, rightseg)
1866 #endif
1867 	       && ((SEG_NORMAL (rightseg)
1868 		    && !S_FORCE_RELOC (resultP->X_add_symbol, 0)
1869 		    && !S_FORCE_RELOC (right.X_add_symbol, 0))
1870 		   || right.X_add_symbol == resultP->X_add_symbol)
1871 	       && frag_offset_fixed_p (symbol_get_frag (resultP->X_add_symbol),
1872 				       symbol_get_frag (right.X_add_symbol),
1873 				       &frag_off))
1874 	{
1875 	  offsetT symval_diff = S_GET_VALUE (resultP->X_add_symbol)
1876 				- S_GET_VALUE (right.X_add_symbol);
1877 	  subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
1878 	  subtract_from_result (resultP, frag_off / OCTETS_PER_BYTE, 0);
1879 	  add_to_result (resultP, symval_diff, symval_diff < 0);
1880 	  resultP->X_op = O_constant;
1881 	  resultP->X_add_symbol = 0;
1882 	}
1883       else if (op_left == O_subtract && right.X_op == O_constant
1884 	       && (md_register_arithmetic || resultP->X_op != O_register))
1885 	{
1886 	  /* X - constant.  */
1887 	  subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
1888 	}
1889       else if (op_left == O_add && resultP->X_op == O_constant
1890 	       && (md_register_arithmetic || right.X_op != O_register))
1891 	{
1892 	  /* Constant + X.  */
1893 	  resultP->X_op = right.X_op;
1894 	  resultP->X_add_symbol = right.X_add_symbol;
1895 	  resultP->X_op_symbol = right.X_op_symbol;
1896 	  add_to_result (resultP, right.X_add_number, right.X_extrabit);
1897 	  retval = rightseg;
1898 	}
1899       else if (resultP->X_op == O_constant && right.X_op == O_constant)
1900 	{
1901 	  /* Constant OP constant.  */
1902 	  offsetT v = right.X_add_number;
1903 	  if (v == 0 && (op_left == O_divide || op_left == O_modulus))
1904 	    {
1905 	      as_warn (_("division by zero"));
1906 	      v = 1;
1907 	    }
1908 	  if ((valueT) v >= sizeof(valueT) * CHAR_BIT
1909 	      && (op_left == O_left_shift || op_left == O_right_shift))
1910 	    {
1911 	      as_warn_value_out_of_range (_("shift count"), v, 0,
1912 					  sizeof(valueT) * CHAR_BIT - 1,
1913 					  NULL, 0);
1914 	      resultP->X_add_number = v = 0;
1915 	    }
1916 	  switch (op_left)
1917 	    {
1918 	    default:			goto general;
1919 	    case O_multiply:		resultP->X_add_number *= v; break;
1920 	    case O_divide:		resultP->X_add_number /= v; break;
1921 	    case O_modulus:		resultP->X_add_number %= v; break;
1922 	    case O_left_shift:		resultP->X_add_number <<= v; break;
1923 	    case O_right_shift:
1924 	      /* We always use unsigned shifts, to avoid relying on
1925 		 characteristics of the compiler used to compile gas.  */
1926 	      resultP->X_add_number =
1927 		(offsetT) ((valueT) resultP->X_add_number >> (valueT) v);
1928 	      break;
1929 	    case O_bit_inclusive_or:	resultP->X_add_number |= v; break;
1930 	    case O_bit_or_not:		resultP->X_add_number |= ~v; break;
1931 	    case O_bit_exclusive_or:	resultP->X_add_number ^= v; break;
1932 	    case O_bit_and:		resultP->X_add_number &= v; break;
1933 	      /* Constant + constant (O_add) is handled by the
1934 		 previous if statement for constant + X, so is omitted
1935 		 here.  */
1936 	    case O_subtract:
1937 	      subtract_from_result (resultP, v, 0);
1938 	      break;
1939 	    case O_eq:
1940 	      resultP->X_add_number =
1941 		resultP->X_add_number == v ? ~ (offsetT) 0 : 0;
1942 	      break;
1943 	    case O_ne:
1944 	      resultP->X_add_number =
1945 		resultP->X_add_number != v ? ~ (offsetT) 0 : 0;
1946 	      break;
1947 	    case O_lt:
1948 	      resultP->X_add_number =
1949 		resultP->X_add_number <  v ? ~ (offsetT) 0 : 0;
1950 	      break;
1951 	    case O_le:
1952 	      resultP->X_add_number =
1953 		resultP->X_add_number <= v ? ~ (offsetT) 0 : 0;
1954 	      break;
1955 	    case O_ge:
1956 	      resultP->X_add_number =
1957 		resultP->X_add_number >= v ? ~ (offsetT) 0 : 0;
1958 	      break;
1959 	    case O_gt:
1960 	      resultP->X_add_number =
1961 		resultP->X_add_number >  v ? ~ (offsetT) 0 : 0;
1962 	      break;
1963 	    case O_logical_and:
1964 	      resultP->X_add_number = resultP->X_add_number && v;
1965 	      break;
1966 	    case O_logical_or:
1967 	      resultP->X_add_number = resultP->X_add_number || v;
1968 	      break;
1969 	    }
1970 	}
1971       else if (resultP->X_op == O_symbol
1972 	       && right.X_op == O_symbol
1973 	       && (op_left == O_add
1974 		   || op_left == O_subtract
1975 		   || (resultP->X_add_number == 0
1976 		       && right.X_add_number == 0)))
1977 	{
1978 	  /* Symbol OP symbol.  */
1979 	  resultP->X_op = op_left;
1980 	  resultP->X_op_symbol = right.X_add_symbol;
1981 	  if (op_left == O_add)
1982 	    add_to_result (resultP, right.X_add_number, right.X_extrabit);
1983 	  else if (op_left == O_subtract)
1984 	    {
1985 	      subtract_from_result (resultP, right.X_add_number,
1986 				    right.X_extrabit);
1987 	      if (retval == rightseg
1988 		  && SEG_NORMAL (retval)
1989 		  && !S_FORCE_RELOC (resultP->X_add_symbol, 0)
1990 		  && !S_FORCE_RELOC (right.X_add_symbol, 0))
1991 		{
1992 		  retval = absolute_section;
1993 		  rightseg = absolute_section;
1994 		}
1995 	    }
1996 	}
1997       else
1998 	{
1999         general:
2000 	  /* The general case.  */
2001 	  resultP->X_add_symbol = make_expr_symbol (resultP);
2002 	  resultP->X_op_symbol = make_expr_symbol (&right);
2003 	  resultP->X_op = op_left;
2004 	  resultP->X_add_number = 0;
2005 	  resultP->X_unsigned = 1;
2006 	  resultP->X_extrabit = 0;
2007 	}
2008 
2009       if (retval != rightseg)
2010 	{
2011 	  if (retval == undefined_section)
2012 	    ;
2013 	  else if (rightseg == undefined_section)
2014 	    retval = rightseg;
2015 	  else if (retval == expr_section)
2016 	    ;
2017 	  else if (rightseg == expr_section)
2018 	    retval = rightseg;
2019 	  else if (retval == reg_section)
2020 	    ;
2021 	  else if (rightseg == reg_section)
2022 	    retval = rightseg;
2023 	  else if (rightseg == absolute_section)
2024 	    ;
2025 	  else if (retval == absolute_section)
2026 	    retval = rightseg;
2027 #ifdef DIFF_EXPR_OK
2028 	  else if (op_left == O_subtract)
2029 	    ;
2030 #endif
2031 	  else
2032 	    as_bad (_("operation combines symbols in different segments"));
2033 	}
2034 
2035       op_left = op_right;
2036     }				/* While next operator is >= this rank.  */
2037 
2038   /* The PA port needs this information.  */
2039   if (resultP->X_add_symbol)
2040     symbol_mark_used (resultP->X_add_symbol);
2041 
2042   if (rank == 0 && mode == expr_evaluate)
2043     resolve_expression (resultP);
2044 
2045   return resultP->X_op == O_constant ? absolute_section : retval;
2046 }
2047 
2048 /* Resolve an expression without changing any symbols/sub-expressions
2049    used.  */
2050 
2051 int
2052 resolve_expression (expressionS *expressionP)
2053 {
2054   /* Help out with CSE.  */
2055   valueT final_val = expressionP->X_add_number;
2056   symbolS *add_symbol = expressionP->X_add_symbol;
2057   symbolS *orig_add_symbol = add_symbol;
2058   symbolS *op_symbol = expressionP->X_op_symbol;
2059   operatorT op = expressionP->X_op;
2060   valueT left, right;
2061   segT seg_left, seg_right;
2062   fragS *frag_left, *frag_right;
2063   offsetT frag_off;
2064 
2065   switch (op)
2066     {
2067     default:
2068       return 0;
2069 
2070     case O_constant:
2071     case O_register:
2072       left = 0;
2073       break;
2074 
2075     case O_symbol:
2076     case O_symbol_rva:
2077       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
2078 	return 0;
2079 
2080       break;
2081 
2082     case O_uminus:
2083     case O_bit_not:
2084     case O_logical_not:
2085       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
2086 	return 0;
2087 
2088       if (seg_left != absolute_section)
2089 	return 0;
2090 
2091       if (op == O_logical_not)
2092 	left = !left;
2093       else if (op == O_uminus)
2094 	left = -left;
2095       else
2096 	left = ~left;
2097       op = O_constant;
2098       break;
2099 
2100     case O_multiply:
2101     case O_divide:
2102     case O_modulus:
2103     case O_left_shift:
2104     case O_right_shift:
2105     case O_bit_inclusive_or:
2106     case O_bit_or_not:
2107     case O_bit_exclusive_or:
2108     case O_bit_and:
2109     case O_add:
2110     case O_subtract:
2111     case O_eq:
2112     case O_ne:
2113     case O_lt:
2114     case O_le:
2115     case O_ge:
2116     case O_gt:
2117     case O_logical_and:
2118     case O_logical_or:
2119       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left)
2120 	  || !snapshot_symbol (&op_symbol, &right, &seg_right, &frag_right))
2121 	return 0;
2122 
2123       /* Simplify addition or subtraction of a constant by folding the
2124 	 constant into X_add_number.  */
2125       if (op == O_add)
2126 	{
2127 	  if (seg_right == absolute_section)
2128 	    {
2129 	      final_val += right;
2130 	      op = O_symbol;
2131 	      break;
2132 	    }
2133 	  else if (seg_left == absolute_section)
2134 	    {
2135 	      final_val += left;
2136 	      left = right;
2137 	      seg_left = seg_right;
2138 	      add_symbol = op_symbol;
2139 	      orig_add_symbol = expressionP->X_op_symbol;
2140 	      op = O_symbol;
2141 	      break;
2142 	    }
2143 	}
2144       else if (op == O_subtract)
2145 	{
2146 	  if (seg_right == absolute_section)
2147 	    {
2148 	      final_val -= right;
2149 	      op = O_symbol;
2150 	      break;
2151 	    }
2152 	}
2153 
2154       /* Equality and non-equality tests are permitted on anything.
2155 	 Subtraction, and other comparison operators are permitted if
2156 	 both operands are in the same section.
2157 	 Shifts by constant zero are permitted on anything.
2158 	 Multiplies, bit-ors, and bit-ands with constant zero are
2159 	 permitted on anything.
2160 	 Multiplies and divides by constant one are permitted on
2161 	 anything.
2162 	 Binary operations with both operands being the same register
2163 	 or undefined symbol are permitted if the result doesn't depend
2164 	 on the input value.
2165 	 Otherwise, both operands must be absolute.  We already handled
2166 	 the case of addition or subtraction of a constant above.  */
2167       frag_off = 0;
2168       if (!(seg_left == absolute_section
2169 	       && seg_right == absolute_section)
2170 	  && !(op == O_eq || op == O_ne)
2171 	  && !((op == O_subtract
2172 		|| op == O_lt || op == O_le || op == O_ge || op == O_gt)
2173 	       && seg_left == seg_right
2174 	       && (finalize_syms
2175 		   || frag_offset_fixed_p (frag_left, frag_right, &frag_off))
2176 	       && (seg_left != reg_section || left == right)
2177 	       && (seg_left != undefined_section || add_symbol == op_symbol)))
2178 	{
2179 	  if ((seg_left == absolute_section && left == 0)
2180 	      || (seg_right == absolute_section && right == 0))
2181 	    {
2182 	      if (op == O_bit_exclusive_or || op == O_bit_inclusive_or)
2183 		{
2184 		  if (!(seg_right == absolute_section && right == 0))
2185 		    {
2186 		      seg_left = seg_right;
2187 		      left = right;
2188 		      add_symbol = op_symbol;
2189 		      orig_add_symbol = expressionP->X_op_symbol;
2190 		    }
2191 		  op = O_symbol;
2192 		  break;
2193 		}
2194 	      else if (op == O_left_shift || op == O_right_shift)
2195 		{
2196 		  if (!(seg_left == absolute_section && left == 0))
2197 		    {
2198 		      op = O_symbol;
2199 		      break;
2200 		    }
2201 		}
2202 	      else if (op != O_multiply
2203 		       && op != O_bit_or_not && op != O_bit_and)
2204 	        return 0;
2205 	    }
2206 	  else if (op == O_multiply
2207 		   && seg_left == absolute_section && left == 1)
2208 	    {
2209 	      seg_left = seg_right;
2210 	      left = right;
2211 	      add_symbol = op_symbol;
2212 	      orig_add_symbol = expressionP->X_op_symbol;
2213 	      op = O_symbol;
2214 	      break;
2215 	    }
2216 	  else if ((op == O_multiply || op == O_divide)
2217 		   && seg_right == absolute_section && right == 1)
2218 	    {
2219 	      op = O_symbol;
2220 	      break;
2221 	    }
2222 	  else if (!(left == right
2223 		     && ((seg_left == reg_section && seg_right == reg_section)
2224 			 || (seg_left == undefined_section
2225 			     && seg_right == undefined_section
2226 			     && add_symbol == op_symbol))))
2227 	    return 0;
2228 	  else if (op == O_bit_and || op == O_bit_inclusive_or)
2229 	    {
2230 	      op = O_symbol;
2231 	      break;
2232 	    }
2233 	  else if (op != O_bit_exclusive_or && op != O_bit_or_not)
2234 	    return 0;
2235 	}
2236 
2237       right += frag_off / OCTETS_PER_BYTE;
2238       switch (op)
2239 	{
2240 	case O_add:			left += right; break;
2241 	case O_subtract:		left -= right; break;
2242 	case O_multiply:		left *= right; break;
2243 	case O_divide:
2244 	  if (right == 0)
2245 	    return 0;
2246 	  left = (offsetT) left / (offsetT) right;
2247 	  break;
2248 	case O_modulus:
2249 	  if (right == 0)
2250 	    return 0;
2251 	  left = (offsetT) left % (offsetT) right;
2252 	  break;
2253 	case O_left_shift:		left <<= right; break;
2254 	case O_right_shift:		left >>= right; break;
2255 	case O_bit_inclusive_or:	left |= right; break;
2256 	case O_bit_or_not:		left |= ~right; break;
2257 	case O_bit_exclusive_or:	left ^= right; break;
2258 	case O_bit_and:			left &= right; break;
2259 	case O_eq:
2260 	case O_ne:
2261 	  left = (left == right
2262 		  && seg_left == seg_right
2263 		  && (finalize_syms || frag_left == frag_right)
2264 		  && (seg_left != undefined_section
2265 		      || add_symbol == op_symbol)
2266 		  ? ~ (valueT) 0 : 0);
2267 	  if (op == O_ne)
2268 	    left = ~left;
2269 	  break;
2270 	case O_lt:
2271 	  left = (offsetT) left <  (offsetT) right ? ~ (valueT) 0 : 0;
2272 	  break;
2273 	case O_le:
2274 	  left = (offsetT) left <= (offsetT) right ? ~ (valueT) 0 : 0;
2275 	  break;
2276 	case O_ge:
2277 	  left = (offsetT) left >= (offsetT) right ? ~ (valueT) 0 : 0;
2278 	  break;
2279 	case O_gt:
2280 	  left = (offsetT) left >  (offsetT) right ? ~ (valueT) 0 : 0;
2281 	  break;
2282 	case O_logical_and:	left = left && right; break;
2283 	case O_logical_or:	left = left || right; break;
2284 	default:		abort ();
2285 	}
2286 
2287       op = O_constant;
2288       break;
2289     }
2290 
2291   if (op == O_symbol)
2292     {
2293       if (seg_left == absolute_section)
2294 	op = O_constant;
2295       else if (seg_left == reg_section && final_val == 0)
2296 	op = O_register;
2297       else if (!symbol_same_p (add_symbol, orig_add_symbol))
2298 	final_val += left;
2299       expressionP->X_add_symbol = add_symbol;
2300     }
2301   expressionP->X_op = op;
2302 
2303   if (op == O_constant || op == O_register)
2304     final_val += left;
2305   expressionP->X_add_number = final_val;
2306 
2307   return 1;
2308 }
2309 
2310 /* This lives here because it belongs equally in expr.c & read.c.
2311    expr.c is just a branch office read.c anyway, and putting it
2312    here lessens the crowd at read.c.
2313 
2314    Assume input_line_pointer is at start of symbol name, or the
2315     start of a double quote enclosed symbol name.
2316    Advance input_line_pointer past symbol name.
2317    Turn that character into a '\0', returning its former value,
2318     which may be the closing double quote.
2319    This allows a string compare (RMS wants symbol names to be strings)
2320     of the symbol name.
2321    There will always be a char following symbol name, because all good
2322    lines end in end-of-line.  */
2323 
2324 char
2325 get_symbol_name (char ** ilp_return)
2326 {
2327   char c;
2328 
2329   * ilp_return = input_line_pointer;
2330   /* We accept FAKE_LABEL_CHAR in a name in case this is being called with a
2331      constructed string.  */
2332   if (is_name_beginner (c = *input_line_pointer++)
2333       || (input_from_string && c == FAKE_LABEL_CHAR))
2334     {
2335       while (is_part_of_name (c = *input_line_pointer++)
2336 	     || (input_from_string && c == FAKE_LABEL_CHAR))
2337 	;
2338       if (is_name_ender (c))
2339 	c = *input_line_pointer++;
2340     }
2341   else if (c == '"')
2342     {
2343       bfd_boolean backslash_seen;
2344 
2345       * ilp_return = input_line_pointer;
2346       do
2347 	{
2348 	  backslash_seen = c == '\\';
2349 	  c = * input_line_pointer ++;
2350 	}
2351       while (c != 0 && (c != '"' || backslash_seen));
2352 
2353       if (c == 0)
2354 	as_warn (_("missing closing '\"'"));
2355     }
2356   *--input_line_pointer = 0;
2357   return c;
2358 }
2359 
2360 /* Replace the NUL character pointed to by input_line_pointer
2361    with C.  If C is \" then advance past it.  Return the character
2362    now pointed to by input_line_pointer.  */
2363 
2364 char
2365 restore_line_pointer (char c)
2366 {
2367   * input_line_pointer = c;
2368   if (c == '"')
2369     c = * ++ input_line_pointer;
2370   return c;
2371 }
2372 
2373 unsigned int
2374 get_single_number (void)
2375 {
2376   expressionS exp;
2377   operand (&exp, expr_normal);
2378   return exp.X_add_number;
2379 }
2380