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  1. /* expr.c -operands, expressions-
  2.    Copyright (C) 1987-2015 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. extern const char EXP_CHARS[], FLT_CHARS[];
  50.  
  51. /* We keep a mapping of expression symbols to file positions, so that
  52.    we can provide better error messages.  */
  53.  
  54. struct expr_symbol_line {
  55.   struct expr_symbol_line *next;
  56.   symbolS *sym;
  57.   char *file;
  58.   unsigned int line;
  59. };
  60.  
  61. static struct expr_symbol_line *expr_symbol_lines;
  63. /* Build a dummy symbol to hold a complex expression.  This is how we
  64.    build expressions up out of other expressions.  The symbol is put
  65.    into the fake section expr_section.  */
  66.  
  67. symbolS *
  68. make_expr_symbol (expressionS *expressionP)
  69. {
  70.   expressionS zero;
  71.   symbolS *symbolP;
  72.   struct expr_symbol_line *n;
  73.  
  74.   if (expressionP->X_op == O_symbol
  75.       && expressionP->X_add_number == 0)
  76.     return expressionP->X_add_symbol;
  77.  
  78.   if (expressionP->X_op == O_big)
  79.     {
  80.       /* This won't work, because the actual value is stored in
  81.          generic_floating_point_number or generic_bignum, and we are
  82.          going to lose it if we haven't already.  */
  83.       if (expressionP->X_add_number > 0)
  84.         as_bad (_("bignum invalid"));
  85.       else
  86.         as_bad (_("floating point number invalid"));
  87.       zero.X_op = O_constant;
  88.       zero.X_add_number = 0;
  89.       zero.X_unsigned = 0;
  90.       zero.X_extrabit = 0;
  91.       clean_up_expression (&zero);
  92.       expressionP = &zero;
  93.     }
  94.  
  95.   /* Putting constant symbols in absolute_section rather than
  96.      expr_section is convenient for the old a.out code, for which
  97.      S_GET_SEGMENT does not always retrieve the value put in by
  98.      S_SET_SEGMENT.  */
  99.   symbolP = symbol_create (FAKE_LABEL_NAME,
  100.                            (expressionP->X_op == O_constant
  101.                             ? absolute_section
  102.                             : expressionP->X_op == O_register
  103.                               ? reg_section
  104.                               : expr_section),
  105.                            0, &zero_address_frag);
  106.   symbol_set_value_expression (symbolP, expressionP);
  107.  
  108.   if (expressionP->X_op == O_constant)
  109.     resolve_symbol_value (symbolP);
  110.  
  111.   n = (struct expr_symbol_line *) xmalloc (sizeof *n);
  112.   n->sym = symbolP;
  113.   as_where (&n->file, &n->line);
  114.   n->next = expr_symbol_lines;
  115.   expr_symbol_lines = n;
  116.  
  117.   return symbolP;
  118. }
  119.  
  120. /* Return the file and line number for an expr symbol.  Return
  121.    non-zero if something was found, 0 if no information is known for
  122.    the symbol.  */
  123.  
  124. int
  125. expr_symbol_where (symbolS *sym, char **pfile, unsigned int *pline)
  126. {
  127.   struct expr_symbol_line *l;
  128.  
  129.   for (l = expr_symbol_lines; l != NULL; l = l->next)
  130.     {
  131.       if (l->sym == sym)
  132.         {
  133.           *pfile = l->file;
  134.           *pline = l->line;
  135.           return 1;
  136.         }
  137.     }
  138.  
  139.   return 0;
  140. }
  142. /* Utilities for building expressions.
  143.    Since complex expressions are recorded as symbols for use in other
  144.    expressions these return a symbolS * and not an expressionS *.
  145.    These explicitly do not take an "add_number" argument.  */
  146. /* ??? For completeness' sake one might want expr_build_symbol.
  147.    It would just return its argument.  */
  148.  
  149. /* Build an expression for an unsigned constant.
  150.    The corresponding one for signed constants is missing because
  151.    there's currently no need for it.  One could add an unsigned_p flag
  152.    but that seems more clumsy.  */
  153.  
  154. symbolS *
  155. expr_build_uconstant (offsetT value)
  156. {
  157.   expressionS e;
  158.  
  159.   e.X_op = O_constant;
  160.   e.X_add_number = value;
  161.   e.X_unsigned = 1;
  162.   e.X_extrabit = 0;
  163.   return make_expr_symbol (&e);
  164. }
  165.  
  166. /* Build an expression for the current location ('.').  */
  167.  
  168. symbolS *
  169. expr_build_dot (void)
  170. {
  171.   expressionS e;
  172.  
  173.   current_location (&e);
  174.   return symbol_clone_if_forward_ref (make_expr_symbol (&e));
  175. }
  177. /* Build any floating-point literal here.
  178.    Also build any bignum literal here.  */
  179.  
  180. /* Seems atof_machine can backscan through generic_bignum and hit whatever
  181.    happens to be loaded before it in memory.  And its way too complicated
  182.    for me to fix right.  Thus a hack.  JF:  Just make generic_bignum bigger,
  183.    and never write into the early words, thus they'll always be zero.
  184.    I hate Dean's floating-point code.  Bleh.  */
  185. LITTLENUM_TYPE generic_bignum[SIZE_OF_LARGE_NUMBER + 6];
  186.  
  187. FLONUM_TYPE generic_floating_point_number = {
  188.   &generic_bignum[6],           /* low.  (JF: Was 0)  */
  189.   &generic_bignum[SIZE_OF_LARGE_NUMBER + 6 - 1], /* high.  JF: (added +6)  */
  190.   0,                            /* leader.  */
  191.   0,                            /* exponent.  */
  192.   0                             /* sign.  */
  193. };
  194.  
  196. static void
  197. floating_constant (expressionS *expressionP)
  198. {
  199.   /* input_line_pointer -> floating-point constant.  */
  200.   int error_code;
  201.  
  202.   error_code = atof_generic (&input_line_pointer, ".", EXP_CHARS,
  203.                              &generic_floating_point_number);
  204.  
  205.   if (error_code)
  206.     {
  207.       if (error_code == ERROR_EXPONENT_OVERFLOW)
  208.         {
  209.           as_bad (_("bad floating-point constant: exponent overflow"));
  210.         }
  211.       else
  212.         {
  213.           as_bad (_("bad floating-point constant: unknown error code=%d"),
  214.                   error_code);
  215.         }
  216.     }
  217.   expressionP->X_op = O_big;
  218.   /* input_line_pointer -> just after constant, which may point to
  219.      whitespace.  */
  220.   expressionP->X_add_number = -1;
  221. }
  222.  
  223. static valueT
  224. generic_bignum_to_int32 (void)
  225. {
  226.   valueT number =
  227.            ((generic_bignum[1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS)
  228.            | (generic_bignum[0] & LITTLENUM_MASK);
  229.   number &= 0xffffffff;
  230.   return number;
  231. }
  232.  
  233. #ifdef BFD64
  234. static valueT
  235. generic_bignum_to_int64 (void)
  236. {
  237.   valueT number =
  238.     ((((((((valueT) generic_bignum[3] & LITTLENUM_MASK)
  239.           << LITTLENUM_NUMBER_OF_BITS)
  240.          | ((valueT) generic_bignum[2] & LITTLENUM_MASK))
  241.         << LITTLENUM_NUMBER_OF_BITS)
  242.        | ((valueT) generic_bignum[1] & LITTLENUM_MASK))
  243.       << LITTLENUM_NUMBER_OF_BITS)
  244.      | ((valueT) generic_bignum[0] & LITTLENUM_MASK));
  245.   return number;
  246. }
  247. #endif
  248.  
  249. static void
  250. integer_constant (int radix, expressionS *expressionP)
  251. {
  252.   char *start;          /* Start of number.  */
  253.   char *suffix = NULL;
  254.   char c;
  255.   valueT number;        /* Offset or (absolute) value.  */
  256.   short int digit;      /* Value of next digit in current radix.  */
  257.   short int maxdig = 0; /* Highest permitted digit value.  */
  258.   int too_many_digits = 0;      /* If we see >= this number of.  */
  259.   char *name;           /* Points to name of symbol.  */
  260.   symbolS *symbolP;     /* Points to symbol.  */
  261.  
  262.   int small;                    /* True if fits in 32 bits.  */
  263.  
  264.   /* May be bignum, or may fit in 32 bits.  */
  265.   /* Most numbers fit into 32 bits, and we want this case to be fast.
  266.      so we pretend it will fit into 32 bits.  If, after making up a 32
  267.      bit number, we realise that we have scanned more digits than
  268.      comfortably fit into 32 bits, we re-scan the digits coding them
  269.      into a bignum.  For decimal and octal numbers we are
  270.      conservative: Some numbers may be assumed bignums when in fact
  271.      they do fit into 32 bits.  Numbers of any radix can have excess
  272.      leading zeros: We strive to recognise this and cast them back
  273.      into 32 bits.  We must check that the bignum really is more than
  274.      32 bits, and change it back to a 32-bit number if it fits.  The
  275.      number we are looking for is expected to be positive, but if it
  276.      fits into 32 bits as an unsigned number, we let it be a 32-bit
  277.      number.  The cavalier approach is for speed in ordinary cases.  */
  278.   /* This has been extended for 64 bits.  We blindly assume that if
  279.      you're compiling in 64-bit mode, the target is a 64-bit machine.
  280.      This should be cleaned up.  */
  281.  
  282. #ifdef BFD64
  283. #define valuesize 64
  284. #else /* includes non-bfd case, mostly */
  285. #define valuesize 32
  286. #endif
  287.  
  288.   if (is_end_of_line[(unsigned char) *input_line_pointer])
  289.     {
  290.       expressionP->X_op = O_absent;
  291.       return;
  292.     }
  293.  
  294.   if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri) && radix == 0)
  295.     {
  296.       int flt = 0;
  297.  
  298.       /* In MRI mode, the number may have a suffix indicating the
  299.          radix.  For that matter, it might actually be a floating
  300.          point constant.  */
  301.       for (suffix = input_line_pointer; ISALNUM (*suffix); suffix++)
  302.         {
  303.           if (*suffix == 'e' || *suffix == 'E')
  304.             flt = 1;
  305.         }
  306.  
  307.       if (suffix == input_line_pointer)
  308.         {
  309.           radix = 10;
  310.           suffix = NULL;
  311.         }
  312.       else
  313.         {
  314.           c = *--suffix;
  315.           c = TOUPPER (c);
  316.           /* If we have both NUMBERS_WITH_SUFFIX and LOCAL_LABELS_FB,
  317.              we distinguish between 'B' and 'b'.  This is the case for
  318.              Z80.  */
  319.           if ((NUMBERS_WITH_SUFFIX && LOCAL_LABELS_FB ? *suffix : c) == 'B')
  320.             radix = 2;
  321.           else if (c == 'D')
  322.             radix = 10;
  323.           else if (c == 'O' || c == 'Q')
  324.             radix = 8;
  325.           else if (c == 'H')
  326.             radix = 16;
  327.           else if (suffix[1] == '.' || c == 'E' || flt)
  328.             {
  329.               floating_constant (expressionP);
  330.               return;
  331.             }
  332.           else
  333.             {
  334.               radix = 10;
  335.               suffix = NULL;
  336.             }
  337.         }
  338.     }
  339.  
  340.   switch (radix)
  341.     {
  342.     case 2:
  343.       maxdig = 2;
  344.       too_many_digits = valuesize + 1;
  345.       break;
  346.     case 8:
  347.       maxdig = radix = 8;
  348.       too_many_digits = (valuesize + 2) / 3 + 1;
  349.       break;
  350.     case 16:
  351.       maxdig = radix = 16;
  352.       too_many_digits = (valuesize + 3) / 4 + 1;
  353.       break;
  354.     case 10:
  355.       maxdig = radix = 10;
  356.       too_many_digits = (valuesize + 11) / 4; /* Very rough.  */
  357.     }
  358. #undef valuesize
  359.   start = input_line_pointer;
  360.   c = *input_line_pointer++;
  361.   for (number = 0;
  362.        (digit = hex_value (c)) < maxdig;
  363.        c = *input_line_pointer++)
  364.     {
  365.       number = number * radix + digit;
  366.     }
  367.   /* c contains character after number.  */
  368.   /* input_line_pointer->char after c.  */
  369.   small = (input_line_pointer - start - 1) < too_many_digits;
  370.  
  371.   if (radix == 16 && c == '_')
  372.     {
  373.       /* This is literal of the form 0x333_0_12345678_1.
  374.          This example is equivalent to 0x00000333000000001234567800000001.  */
  375.  
  376.       int num_little_digits = 0;
  377.       int i;
  378.       input_line_pointer = start;       /* -> 1st digit.  */
  379.  
  380.       know (LITTLENUM_NUMBER_OF_BITS == 16);
  381.  
  382.       for (c = '_'; c == '_'; num_little_digits += 2)
  383.         {
  384.  
  385.           /* Convert one 64-bit word.  */
  386.           int ndigit = 0;
  387.           number = 0;
  388.           for (c = *input_line_pointer++;
  389.                (digit = hex_value (c)) < maxdig;
  390.                c = *(input_line_pointer++))
  391.             {
  392.               number = number * radix + digit;
  393.               ndigit++;
  394.             }
  395.  
  396.           /* Check for 8 digit per word max.  */
  397.           if (ndigit > 8)
  398.             as_bad (_("a bignum with underscores may not have more than 8 hex digits in any word"));
  399.  
  400.           /* Add this chunk to the bignum.
  401.              Shift things down 2 little digits.  */
  402.           know (LITTLENUM_NUMBER_OF_BITS == 16);
  403.           for (i = min (num_little_digits + 1, SIZE_OF_LARGE_NUMBER - 1);
  404.                i >= 2;
  405.                i--)
  406.             generic_bignum[i] = generic_bignum[i - 2];
  407.  
  408.           /* Add the new digits as the least significant new ones.  */
  409.           generic_bignum[0] = number & 0xffffffff;
  410.           generic_bignum[1] = number >> 16;
  411.         }
  412.  
  413.       /* Again, c is char after number, input_line_pointer->after c.  */
  414.  
  415.       if (num_little_digits > SIZE_OF_LARGE_NUMBER - 1)
  416.         num_little_digits = SIZE_OF_LARGE_NUMBER - 1;
  417.  
  418.       gas_assert (num_little_digits >= 4);
  419.  
  420.       if (num_little_digits != 8)
  421.         as_bad (_("a bignum with underscores must have exactly 4 words"));
  422.  
  423.       /* We might have some leading zeros.  These can be trimmed to give
  424.          us a change to fit this constant into a small number.  */
  425.       while (generic_bignum[num_little_digits - 1] == 0
  426.              && num_little_digits > 1)
  427.         num_little_digits--;
  428.  
  429.       if (num_little_digits <= 2)
  430.         {
  431.           /* will fit into 32 bits.  */
  432.           number = generic_bignum_to_int32 ();
  433.           small = 1;
  434.         }
  435. #ifdef BFD64
  436.       else if (num_little_digits <= 4)
  437.         {
  438.           /* Will fit into 64 bits.  */
  439.           number = generic_bignum_to_int64 ();
  440.           small = 1;
  441.         }
  442. #endif
  443.       else
  444.         {
  445.           small = 0;
  446.  
  447.           /* Number of littlenums in the bignum.  */
  448.           number = num_little_digits;
  449.         }
  450.     }
  451.   else if (!small)
  452.     {
  453.       /* We saw a lot of digits. manufacture a bignum the hard way.  */
  454.       LITTLENUM_TYPE *leader;   /* -> high order littlenum of the bignum.  */
  455.       LITTLENUM_TYPE *pointer;  /* -> littlenum we are frobbing now.  */
  456.       long carry;
  457.  
  458.       leader = generic_bignum;
  459.       generic_bignum[0] = 0;
  460.       generic_bignum[1] = 0;
  461.       generic_bignum[2] = 0;
  462.       generic_bignum[3] = 0;
  463.       input_line_pointer = start;       /* -> 1st digit.  */
  464.       c = *input_line_pointer++;
  465.       for (; (carry = hex_value (c)) < maxdig; c = *input_line_pointer++)
  466.         {
  467.           for (pointer = generic_bignum; pointer <= leader; pointer++)
  468.             {
  469.               long work;
  470.  
  471.               work = carry + radix * *pointer;
  472.               *pointer = work & LITTLENUM_MASK;
  473.               carry = work >> LITTLENUM_NUMBER_OF_BITS;
  474.             }
  475.           if (carry)
  476.             {
  477.               if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1)
  478.                 {
  479.                   /* Room to grow a longer bignum.  */
  480.                   *++leader = carry;
  481.                 }
  482.             }
  483.         }
  484.       /* Again, c is char after number.  */
  485.       /* input_line_pointer -> after c.  */
  486.       know (LITTLENUM_NUMBER_OF_BITS == 16);
  487.       if (leader < generic_bignum + 2)
  488.         {
  489.           /* Will fit into 32 bits.  */
  490.           number = generic_bignum_to_int32 ();
  491.           small = 1;
  492.         }
  493. #ifdef BFD64
  494.       else if (leader < generic_bignum + 4)
  495.         {
  496.           /* Will fit into 64 bits.  */
  497.           number = generic_bignum_to_int64 ();
  498.           small = 1;
  499.         }
  500. #endif
  501.       else
  502.         {
  503.           /* Number of littlenums in the bignum.  */
  504.           number = leader - generic_bignum + 1;
  505.         }
  506.     }
  507.  
  508.   if ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)
  509.       && suffix != NULL
  510.       && input_line_pointer - 1 == suffix)
  511.     c = *input_line_pointer++;
  512.  
  513.   if (small)
  514.     {
  515.       /* Here with number, in correct radix. c is the next char.
  516.          Note that unlike un*x, we allow "011f" "0x9f" to both mean
  517.          the same as the (conventional) "9f".
  518.          This is simply easier than checking for strict canonical
  519.          form.  Syntax sux!  */
  520.  
  521.       if (LOCAL_LABELS_FB && c == 'b')
  522.         {
  523.           /* Backward ref to local label.
  524.              Because it is backward, expect it to be defined.  */
  525.           /* Construct a local label.  */
  526.           name = fb_label_name ((int) number, 0);
  527.  
  528.           /* Seen before, or symbol is defined: OK.  */
  529.           symbolP = symbol_find (name);
  530.           if ((symbolP != NULL) && (S_IS_DEFINED (symbolP)))
  531.             {
  532.               /* Local labels are never absolute.  Don't waste time
  533.                  checking absoluteness.  */
  534.               know (SEG_NORMAL (S_GET_SEGMENT (symbolP)));
  535.  
  536.               expressionP->X_op = O_symbol;
  537.               expressionP->X_add_symbol = symbolP;
  538.             }
  539.           else
  540.             {
  541.               /* Either not seen or not defined.  */
  542.               /* @@ Should print out the original string instead of
  543.                  the parsed number.  */
  544.               as_bad (_("backward ref to unknown label \"%d:\""),
  545.                       (int) number);
  546.               expressionP->X_op = O_constant;
  547.             }
  548.  
  549.           expressionP->X_add_number = 0;
  550.         }                       /* case 'b' */
  551.       else if (LOCAL_LABELS_FB && c == 'f')
  552.         {
  553.           /* Forward reference.  Expect symbol to be undefined or
  554.              unknown.  undefined: seen it before.  unknown: never seen
  555.              it before.
  556.  
  557.              Construct a local label name, then an undefined symbol.
  558.              Don't create a xseg frag for it: caller may do that.
  559.              Just return it as never seen before.  */
  560.           name = fb_label_name ((int) number, 1);
  561.           symbolP = symbol_find_or_make (name);
  562.           /* We have no need to check symbol properties.  */
  563. #ifndef many_segments
  564.           /* Since "know" puts its arg into a "string", we
  565.              can't have newlines in the argument.  */
  566.           know (S_GET_SEGMENT (symbolP) == undefined_section || S_GET_SEGMENT (symbolP) == text_section || S_GET_SEGMENT (symbolP) == data_section);
  567. #endif
  568.           expressionP->X_op = O_symbol;
  569.           expressionP->X_add_symbol = symbolP;
  570.           expressionP->X_add_number = 0;
  571.         }                       /* case 'f' */
  572.       else if (LOCAL_LABELS_DOLLAR && c == '$')
  573.         {
  574.           /* If the dollar label is *currently* defined, then this is just
  575.              another reference to it.  If it is not *currently* defined,
  576.              then this is a fresh instantiation of that number, so create
  577.              it.  */
  578.  
  579.           if (dollar_label_defined ((long) number))
  580.             {
  581.               name = dollar_label_name ((long) number, 0);
  582.               symbolP = symbol_find (name);
  583.               know (symbolP != NULL);
  584.             }
  585.           else
  586.             {
  587.               name = dollar_label_name ((long) number, 1);
  588.               symbolP = symbol_find_or_make (name);
  589.             }
  590.  
  591.           expressionP->X_op = O_symbol;
  592.           expressionP->X_add_symbol = symbolP;
  593.           expressionP->X_add_number = 0;
  594.         }                       /* case '$' */
  595.       else
  596.         {
  597.           expressionP->X_op = O_constant;
  598.           expressionP->X_add_number = number;
  599.           input_line_pointer--; /* Restore following character.  */
  600.         }                       /* Really just a number.  */
  601.     }
  602.   else
  603.     {
  604.       /* Not a small number.  */
  605.       expressionP->X_op = O_big;
  606.       expressionP->X_add_number = number;       /* Number of littlenums.  */
  607.       input_line_pointer--;     /* -> char following number.  */
  608.     }
  609. }
  610.  
  611. /* Parse an MRI multi character constant.  */
  612.  
  613. static void
  614. mri_char_constant (expressionS *expressionP)
  615. {
  616.   int i;
  617.  
  618.   if (*input_line_pointer == '\''
  619.       && input_line_pointer[1] != '\'')
  620.     {
  621.       expressionP->X_op = O_constant;
  622.       expressionP->X_add_number = 0;
  623.       return;
  624.     }
  625.  
  626.   /* In order to get the correct byte ordering, we must build the
  627.      number in reverse.  */
  628.   for (i = SIZE_OF_LARGE_NUMBER - 1; i >= 0; i--)
  629.     {
  630.       int j;
  631.  
  632.       generic_bignum[i] = 0;
  633.       for (j = 0; j < CHARS_PER_LITTLENUM; j++)
  634.         {
  635.           if (*input_line_pointer == '\'')
  636.             {
  637.               if (input_line_pointer[1] != '\'')
  638.                 break;
  639.               ++input_line_pointer;
  640.             }
  641.           generic_bignum[i] <<= 8;
  642.           generic_bignum[i] += *input_line_pointer;
  643.           ++input_line_pointer;
  644.         }
  645.  
  646.       if (i < SIZE_OF_LARGE_NUMBER - 1)
  647.         {
  648.           /* If there is more than one littlenum, left justify the
  649.              last one to make it match the earlier ones.  If there is
  650.              only one, we can just use the value directly.  */
  651.           for (; j < CHARS_PER_LITTLENUM; j++)
  652.             generic_bignum[i] <<= 8;
  653.         }
  654.  
  655.       if (*input_line_pointer == '\''
  656.           && input_line_pointer[1] != '\'')
  657.         break;
  658.     }
  659.  
  660.   if (i < 0)
  661.     {
  662.       as_bad (_("character constant too large"));
  663.       i = 0;
  664.     }
  665.  
  666.   if (i > 0)
  667.     {
  668.       int c;
  669.       int j;
  670.  
  671.       c = SIZE_OF_LARGE_NUMBER - i;
  672.       for (j = 0; j < c; j++)
  673.         generic_bignum[j] = generic_bignum[i + j];
  674.       i = c;
  675.     }
  676.  
  677.   know (LITTLENUM_NUMBER_OF_BITS == 16);
  678.   if (i > 2)
  679.     {
  680.       expressionP->X_op = O_big;
  681.       expressionP->X_add_number = i;
  682.     }
  683.   else
  684.     {
  685.       expressionP->X_op = O_constant;
  686.       if (i < 2)
  687.         expressionP->X_add_number = generic_bignum[0] & LITTLENUM_MASK;
  688.       else
  689.         expressionP->X_add_number =
  690.           (((generic_bignum[1] & LITTLENUM_MASK)
  691.             << LITTLENUM_NUMBER_OF_BITS)
  692.            | (generic_bignum[0] & LITTLENUM_MASK));
  693.     }
  694.  
  695.   /* Skip the final closing quote.  */
  696.   ++input_line_pointer;
  697. }
  698.  
  699. /* Return an expression representing the current location.  This
  700.    handles the magic symbol `.'.  */
  701.  
  702. void
  703. current_location (expressionS *expressionp)
  704. {
  705.   if (now_seg == absolute_section)
  706.     {
  707.       expressionp->X_op = O_constant;
  708.       expressionp->X_add_number = abs_section_offset;
  709.     }
  710.   else
  711.     {
  712.       expressionp->X_op = O_symbol;
  713.       expressionp->X_add_symbol = &dot_symbol;
  714.       expressionp->X_add_number = 0;
  715.     }
  716. }
  717.  
  718. /* In:  Input_line_pointer points to 1st char of operand, which may
  719.         be a space.
  720.  
  721.    Out: An expressionS.
  722.         The operand may have been empty: in this case X_op == O_absent.
  723.         Input_line_pointer->(next non-blank) char after operand.  */
  724.  
  725. static segT
  726. operand (expressionS *expressionP, enum expr_mode mode)
  727. {
  728.   char c;
  729.   symbolS *symbolP;     /* Points to symbol.  */
  730.   char *name;           /* Points to name of symbol.  */
  731.   segT segment;
  732.  
  733.   /* All integers are regarded as unsigned unless they are negated.
  734.      This is because the only thing which cares whether a number is
  735.      unsigned is the code in emit_expr which extends constants into
  736.      bignums.  It should only sign extend negative numbers, so that
  737.      something like ``.quad 0x80000000'' is not sign extended even
  738.      though it appears negative if valueT is 32 bits.  */
  739.   expressionP->X_unsigned = 1;
  740.   expressionP->X_extrabit = 0;
  741.  
  742.   /* Digits, assume it is a bignum.  */
  743.  
  744.   SKIP_WHITESPACE ();           /* Leading whitespace is part of operand.  */
  745.   c = *input_line_pointer++;    /* input_line_pointer -> past char in c.  */
  746.  
  747.   if (is_end_of_line[(unsigned char) c])
  748.     goto eol;
  749.  
  750.   switch (c)
  751.     {
  752.     case '1':
  753.     case '2':
  754.     case '3':
  755.     case '4':
  756.     case '5':
  757.     case '6':
  758.     case '7':
  759.     case '8':
  760.     case '9':
  761.       input_line_pointer--;
  762.  
  763.       integer_constant ((NUMBERS_WITH_SUFFIX || flag_m68k_mri)
  764.                         ? 0 : 10,
  765.                         expressionP);
  766.       break;
  767.  
  768. #ifdef LITERAL_PREFIXDOLLAR_HEX
  769.     case '$':
  770.       /* $L is the start of a local label, not a hex constant.  */
  771.       if (* input_line_pointer == 'L')
  772.       goto isname;
  773.       integer_constant (16, expressionP);
  774.       break;
  775. #endif
  776.  
  777. #ifdef LITERAL_PREFIXPERCENT_BIN
  778.     case '%':
  779.       integer_constant (2, expressionP);
  780.       break;
  781. #endif
  782.  
  783.     case '0':
  784.       /* Non-decimal radix.  */
  785.  
  786.       if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)
  787.         {
  788.           char *s;
  789.  
  790.           /* Check for a hex or float constant.  */
  791.           for (s = input_line_pointer; hex_p (*s); s++)
  792.             ;
  793.           if (*s == 'h' || *s == 'H' || *input_line_pointer == '.')
  794.             {
  795.               --input_line_pointer;
  796.               integer_constant (0, expressionP);
  797.               break;
  798.             }
  799.         }
  800.       c = *input_line_pointer;
  801.       switch (c)
  802.         {
  803.         case 'o':
  804.         case 'O':
  805.         case 'q':
  806.         case 'Q':
  807.         case '8':
  808.         case '9':
  809.           if (NUMBERS_WITH_SUFFIX || flag_m68k_mri)
  810.             {
  811.               integer_constant (0, expressionP);
  812.               break;
  813.             }
  814.           /* Fall through.  */
  815.         default:
  816.         default_case:
  817.           if (c && strchr (FLT_CHARS, c))
  818.             {
  819.               input_line_pointer++;
  820.               floating_constant (expressionP);
  821.               expressionP->X_add_number = - TOLOWER (c);
  822.             }
  823.           else
  824.             {
  825.               /* The string was only zero.  */
  826.               expressionP->X_op = O_constant;
  827.               expressionP->X_add_number = 0;
  828.             }
  829.  
  830.           break;
  831.  
  832.         case 'x':
  833.         case 'X':
  834.           if (flag_m68k_mri)
  835.             goto default_case;
  836.           input_line_pointer++;
  837.           integer_constant (16, expressionP);
  838.           break;
  839.  
  840.         case 'b':
  841.           if (LOCAL_LABELS_FB && !flag_m68k_mri
  842.               && input_line_pointer[1] != '0'
  843.               && input_line_pointer[1] != '1')
  844.                 {
  845.                   /* Parse this as a back reference to label 0.  */
  846.                   input_line_pointer--;
  847.                   integer_constant (10, expressionP);
  848.                   break;
  849.                 }
  850.               /* Otherwise, parse this as a binary number.  */
  851.           /* Fall through.  */
  852.         case 'B':
  853.           if (input_line_pointer[1] == '0'
  854.               || input_line_pointer[1] == '1')
  855.             {
  856.           input_line_pointer++;
  857.               integer_constant (2, expressionP);
  858.               break;
  859.             }
  860.           if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)
  861.             input_line_pointer++;
  862.             goto default_case;
  863.  
  864.         case '0':
  865.         case '1':
  866.         case '2':
  867.         case '3':
  868.         case '4':
  869.         case '5':
  870.         case '6':
  871.         case '7':
  872.           integer_constant ((flag_m68k_mri || NUMBERS_WITH_SUFFIX)
  873.                             ? 0 : 8,
  874.                             expressionP);
  875.           break;
  876.  
  877.         case 'f':
  878.           if (LOCAL_LABELS_FB)
  879.             {
  880.               int is_label = 1;
  881.  
  882.               /* If it says "0f" and it could possibly be a floating point
  883.                  number, make it one.  Otherwise, make it a local label,
  884.                  and try to deal with parsing the rest later.  */
  885.               if (!is_end_of_line[(unsigned char) input_line_pointer[1]]
  886.                   && strchr (FLT_CHARS, 'f') != NULL)
  887.               {
  888.                 char *cp = input_line_pointer + 1;
  889.  
  890.                   atof_generic (&cp, ".", EXP_CHARS,
  891.                                       &generic_floating_point_number);
  892.  
  893.                   /* Was nothing parsed, or does it look like an
  894.                      expression?  */
  895.                   is_label = (cp == input_line_pointer + 1
  896.                               || (cp == input_line_pointer + 2
  897.                                   && (cp[-1] == '-' || cp[-1] == '+'))
  898.                               || *cp == 'f'
  899.                               || *cp == 'b');
  900.                 }
  901.               if (is_label)
  902.                   {
  903.               input_line_pointer--;
  904.               integer_constant (10, expressionP);
  905.               break;
  906.                 }
  907.             }
  908.               /* Fall through.  */
  909.  
  910.         case 'd':
  911.         case 'D':
  912.           if (flag_m68k_mri || NUMBERS_WITH_SUFFIX)
  913.             {
  914.               integer_constant (0, expressionP);
  915.               break;
  916.             }
  917.           /* Fall through.  */
  918.         case 'F':
  919.         case 'r':
  920.         case 'e':
  921.         case 'E':
  922.         case 'g':
  923.         case 'G':
  924.           input_line_pointer++;
  925.           floating_constant (expressionP);
  926.           expressionP->X_add_number = - TOLOWER (c);
  927.           break;
  928.  
  929.         case '$':
  930.           if (LOCAL_LABELS_DOLLAR)
  931.             {
  932.               integer_constant (10, expressionP);
  933.               break;
  934.             }
  935.           else
  936.             goto default_case;
  937.         }
  938.  
  939.       break;
  940.  
  941. #ifndef NEED_INDEX_OPERATOR
  942.     case '[':
  943. # ifdef md_need_index_operator
  944.       if (md_need_index_operator())
  945.         goto de_fault;
  946. # endif
  947.       /* FALLTHROUGH */
  948. #endif
  949.     case '(':
  950.       /* Didn't begin with digit & not a name.  */
  951.       segment = expr (0, expressionP, mode);
  952.       /* expression () will pass trailing whitespace.  */
  953.       if ((c == '(' && *input_line_pointer != ')')
  954.           || (c == '[' && *input_line_pointer != ']'))
  955.         as_bad (_("missing '%c'"), c == '(' ? ')' : ']');
  956.       else
  957.         input_line_pointer++;
  958.       SKIP_WHITESPACE ();
  959.       /* Here with input_line_pointer -> char after "(...)".  */
  960.       return segment;
  961.  
  962. #ifdef TC_M68K
  963.     case 'E':
  964.       if (! flag_m68k_mri || *input_line_pointer != '\'')
  965.         goto de_fault;
  966.       as_bad (_("EBCDIC constants are not supported"));
  967.       /* Fall through.  */
  968.     case 'A':
  969.       if (! flag_m68k_mri || *input_line_pointer != '\'')
  970.         goto de_fault;
  971.       ++input_line_pointer;
  972.       /* Fall through.  */
  973. #endif
  974.     case '\'':
  975.       if (! flag_m68k_mri)
  976.         {
  977.           /* Warning: to conform to other people's assemblers NO
  978.              ESCAPEMENT is permitted for a single quote.  The next
  979.              character, parity errors and all, is taken as the value
  980.              of the operand.  VERY KINKY.  */
  981.           expressionP->X_op = O_constant;
  982.           expressionP->X_add_number = *input_line_pointer++;
  983.           break;
  984.         }
  985.  
  986.       mri_char_constant (expressionP);
  987.       break;
  988.  
  989. #ifdef TC_M68K
  990.     case '"':
  991.       /* Double quote is the bitwise not operator in MRI mode.  */
  992.       if (! flag_m68k_mri)
  993.         goto de_fault;
  994.       /* Fall through.  */
  995. #endif
  996.     case '~':
  997.       /* '~' is permitted to start a label on the Delta.  */
  998.       if (is_name_beginner (c))
  999.         goto isname;
  1000.     case '!':
  1001.     case '-':
  1002.     case '+':
  1003.       {
  1004. #ifdef md_operator
  1005.       unary:
  1006. #endif
  1007.         operand (expressionP, mode);
  1008.         if (expressionP->X_op == O_constant)
  1009.           {
  1010.             /* input_line_pointer -> char after operand.  */
  1011.             if (c == '-')
  1012.               {
  1013.                 expressionP->X_add_number
  1014.                   = - (addressT) expressionP->X_add_number;
  1015.                 /* Notice: '-' may overflow: no warning is given.
  1016.                    This is compatible with other people's
  1017.                    assemblers.  Sigh.  */
  1018.                 expressionP->X_unsigned = 0;
  1019.                 if (expressionP->X_add_number)
  1020.                   expressionP->X_extrabit ^= 1;
  1021.               }
  1022.             else if (c == '~' || c == '"')
  1023.               expressionP->X_add_number = ~ expressionP->X_add_number;
  1024.             else if (c == '!')
  1025.               expressionP->X_add_number = ! expressionP->X_add_number;
  1026.           }
  1027.         else if (expressionP->X_op == O_big
  1028.                  && expressionP->X_add_number <= 0
  1029.                  && c == '-'
  1030.                  && (generic_floating_point_number.sign == '+'
  1031.                      || generic_floating_point_number.sign == 'P'))
  1032.           {
  1033.             /* Negative flonum (eg, -1.000e0).  */
  1034.             if (generic_floating_point_number.sign == '+')
  1035.               generic_floating_point_number.sign = '-';
  1036.             else
  1037.               generic_floating_point_number.sign = 'N';
  1038.           }
  1039.         else if (expressionP->X_op == O_big
  1040.                  && expressionP->X_add_number > 0)
  1041.           {
  1042.             int i;
  1043.  
  1044.             if (c == '~' || c == '-')
  1045.               {
  1046.                 for (i = 0; i < expressionP->X_add_number; ++i)
  1047.                   generic_bignum[i] = ~generic_bignum[i];
  1048.  
  1049.                 /* Extend the bignum to at least the size of .octa.  */
  1050.                 if (expressionP->X_add_number < SIZE_OF_LARGE_NUMBER)
  1051.                   {
  1052.                     expressionP->X_add_number = SIZE_OF_LARGE_NUMBER;
  1053.                     for (; i < expressionP->X_add_number; ++i)
  1054.                       generic_bignum[i] = ~(LITTLENUM_TYPE) 0;
  1055.                   }
  1056.  
  1057.                 if (c == '-')
  1058.                   for (i = 0; i < expressionP->X_add_number; ++i)
  1059.                     {
  1060.                       generic_bignum[i] += 1;
  1061.                       if (generic_bignum[i])
  1062.                         break;
  1063.                     }
  1064.               }
  1065.             else if (c == '!')
  1066.               {
  1067.                 for (i = 0; i < expressionP->X_add_number; ++i)
  1068.                   if (generic_bignum[i] != 0)
  1069.                     break;
  1070.                 expressionP->X_add_number = i >= expressionP->X_add_number;
  1071.                 expressionP->X_op = O_constant;
  1072.                 expressionP->X_unsigned = 1;
  1073.                 expressionP->X_extrabit = 0;
  1074.               }
  1075.           }
  1076.         else if (expressionP->X_op != O_illegal
  1077.                  && expressionP->X_op != O_absent)
  1078.           {
  1079.             if (c != '+')
  1080.               {
  1081.                 expressionP->X_add_symbol = make_expr_symbol (expressionP);
  1082.                 if (c == '-')
  1083.                   expressionP->X_op = O_uminus;
  1084.                 else if (c == '~' || c == '"')
  1085.                   expressionP->X_op = O_bit_not;
  1086.                 else
  1087.                   expressionP->X_op = O_logical_not;
  1088.                 expressionP->X_add_number = 0;
  1089.               }
  1090.           }
  1091.         else
  1092.           as_warn (_("Unary operator %c ignored because bad operand follows"),
  1093.                    c);
  1094.       }
  1095.       break;
  1096.  
  1097. #if defined (DOLLAR_DOT) || defined (TC_M68K)
  1098.     case '$':
  1099.       /* '$' is the program counter when in MRI mode, or when
  1100.          DOLLAR_DOT is defined.  */
  1101. #ifndef DOLLAR_DOT
  1102.       if (! flag_m68k_mri)
  1103.         goto de_fault;
  1104. #endif
  1105.       if (DOLLAR_AMBIGU && hex_p (*input_line_pointer))
  1106.         {
  1107.           /* In MRI mode and on Z80, '$' is also used as the prefix
  1108.              for a hexadecimal constant.  */
  1109.           integer_constant (16, expressionP);
  1110.           break;
  1111.         }
  1112.  
  1113.       if (is_part_of_name (*input_line_pointer))
  1114.         goto isname;
  1115.  
  1116.       current_location (expressionP);
  1117.       break;
  1118. #endif
  1119.  
  1120.     case '.':
  1121.       if (!is_part_of_name (*input_line_pointer))
  1122.         {
  1123.           current_location (expressionP);
  1124.           break;
  1125.         }
  1126.       else if ((strncasecmp (input_line_pointer, "startof.", 8) == 0
  1127.                 && ! is_part_of_name (input_line_pointer[8]))
  1128.                || (strncasecmp (input_line_pointer, "sizeof.", 7) == 0
  1129.                    && ! is_part_of_name (input_line_pointer[7])))
  1130.         {
  1131.           int start;
  1132.  
  1133.           start = (input_line_pointer[1] == 't'
  1134.                    || input_line_pointer[1] == 'T');
  1135.           input_line_pointer += start ? 8 : 7;
  1136.           SKIP_WHITESPACE ();
  1137.           if (*input_line_pointer != '(')
  1138.             as_bad (_("syntax error in .startof. or .sizeof."));
  1139.           else
  1140.             {
  1141.               char *buf;
  1142.  
  1143.               ++input_line_pointer;
  1144.               SKIP_WHITESPACE ();
  1145.               c = get_symbol_name (& name);
  1146.  
  1147.               buf = (char *) xmalloc (strlen (name) + 10);
  1148.               if (start)
  1149.                 sprintf (buf, ".startof.%s", name);
  1150.               else
  1151.                 sprintf (buf, ".sizeof.%s", name);
  1152.               symbolP = symbol_make (buf);
  1153.               free (buf);
  1154.  
  1155.               expressionP->X_op = O_symbol;
  1156.               expressionP->X_add_symbol = symbolP;
  1157.               expressionP->X_add_number = 0;
  1158.  
  1159.               *input_line_pointer = c;
  1160.               SKIP_WHITESPACE_AFTER_NAME ();
  1161.               if (*input_line_pointer != ')')
  1162.                 as_bad (_("syntax error in .startof. or .sizeof."));
  1163.               else
  1164.                 ++input_line_pointer;
  1165.             }
  1166.           break;
  1167.         }
  1168.       else
  1169.         {
  1170.           goto isname;
  1171.         }
  1172.  
  1173.     case ',':
  1174.     eol:
  1175.       /* Can't imagine any other kind of operand.  */
  1176.       expressionP->X_op = O_absent;
  1177.       input_line_pointer--;
  1178.       break;
  1179.  
  1180. #ifdef TC_M68K
  1181.     case '%':
  1182.       if (! flag_m68k_mri)
  1183.         goto de_fault;
  1184.       integer_constant (2, expressionP);
  1185.       break;
  1186.  
  1187.     case '@':
  1188.       if (! flag_m68k_mri)
  1189.         goto de_fault;
  1190.       integer_constant (8, expressionP);
  1191.       break;
  1192.  
  1193.     case ':':
  1194.       if (! flag_m68k_mri)
  1195.         goto de_fault;
  1196.  
  1197.       /* In MRI mode, this is a floating point constant represented
  1198.          using hexadecimal digits.  */
  1199.  
  1200.       ++input_line_pointer;
  1201.       integer_constant (16, expressionP);
  1202.       break;
  1203.  
  1204.     case '*':
  1205.       if (! flag_m68k_mri || is_part_of_name (*input_line_pointer))
  1206.         goto de_fault;
  1207.  
  1208.       current_location (expressionP);
  1209.       break;
  1210. #endif
  1211.  
  1212.     default:
  1213. #if defined(md_need_index_operator) || defined(TC_M68K)
  1214.     de_fault:
  1215. #endif
  1216.       if (is_name_beginner (c) || c == '"')     /* Here if did not begin with a digit.  */
  1217.         {
  1218.           /* Identifier begins here.
  1219.              This is kludged for speed, so code is repeated.  */
  1220.         isname:
  1221.           -- input_line_pointer;
  1222.           c = get_symbol_name (&name);
  1223.  
  1224. #ifdef md_operator
  1225.           {
  1226.             operatorT op = md_operator (name, 1, &c);
  1227.  
  1228.             switch (op)
  1229.               {
  1230.               case O_uminus:
  1231.                 restore_line_pointer (c);
  1232.                 c = '-';
  1233.                 goto unary;
  1234.               case O_bit_not:
  1235.                 restore_line_pointer (c);
  1236.                 c = '~';
  1237.                 goto unary;
  1238.               case O_logical_not:
  1239.                 restore_line_pointer (c);
  1240.                 c = '!';
  1241.                 goto unary;
  1242.               case O_illegal:
  1243.                 as_bad (_("invalid use of operator \"%s\""), name);
  1244.                 break;
  1245.               default:
  1246.                 break;
  1247.               }
  1248.  
  1249.             if (op != O_absent && op != O_illegal)
  1250.               {
  1251.                 restore_line_pointer (c);
  1252.                 expr (9, expressionP, mode);
  1253.                 expressionP->X_add_symbol = make_expr_symbol (expressionP);
  1254.                 expressionP->X_op_symbol = NULL;
  1255.                 expressionP->X_add_number = 0;
  1256.                 expressionP->X_op = op;
  1257.                 break;
  1258.               }
  1259.           }
  1260. #endif
  1261.  
  1262. #ifdef md_parse_name
  1263.           /* This is a hook for the backend to parse certain names
  1264.              specially in certain contexts.  If a name always has a
  1265.              specific value, it can often be handled by simply
  1266.              entering it in the symbol table.  */
  1267.           if (md_parse_name (name, expressionP, mode, &c))
  1268.             {
  1269.               restore_line_pointer (c);
  1270.               break;
  1271.             }
  1272. #endif
  1273.  
  1274. #ifdef TC_I960
  1275.           /* The MRI i960 assembler permits
  1276.                  lda sizeof code,g13
  1277.              FIXME: This should use md_parse_name.  */
  1278.           if (flag_mri
  1279.               && (strcasecmp (name, "sizeof") == 0
  1280.                   || strcasecmp (name, "startof") == 0))
  1281.             {
  1282.               int start;
  1283.               char *buf;
  1284.  
  1285.               start = (name[1] == 't'
  1286.                        || name[1] == 'T');
  1287.  
  1288.               *input_line_pointer = c;
  1289.               SKIP_WHITESPACE_AFTER_NAME ();
  1290.  
  1291.               c = get_symbol_name (& name);
  1292.  
  1293.               buf = (char *) xmalloc (strlen (name) + 10);
  1294.               if (start)
  1295.                 sprintf (buf, ".startof.%s", name);
  1296.               else
  1297.                 sprintf (buf, ".sizeof.%s", name);
  1298.               symbolP = symbol_make (buf);
  1299.               free (buf);
  1300.  
  1301.               expressionP->X_op = O_symbol;
  1302.               expressionP->X_add_symbol = symbolP;
  1303.               expressionP->X_add_number = 0;
  1304.  
  1305.               *input_line_pointer = c;
  1306.               SKIP_WHITESPACE_AFTER_NAME ();
  1307.               break;
  1308.             }
  1309. #endif
  1310.  
  1311.           symbolP = symbol_find_or_make (name);
  1312.  
  1313.           /* If we have an absolute symbol or a reg, then we know its
  1314.              value now.  */
  1315.           segment = S_GET_SEGMENT (symbolP);
  1316.           if (mode != expr_defer
  1317.               && segment == absolute_section
  1318.               && !S_FORCE_RELOC (symbolP, 0))
  1319.             {
  1320.               expressionP->X_op = O_constant;
  1321.               expressionP->X_add_number = S_GET_VALUE (symbolP);
  1322.             }
  1323.           else if (mode != expr_defer && segment == reg_section)
  1324.             {
  1325.               expressionP->X_op = O_register;
  1326.               expressionP->X_add_number = S_GET_VALUE (symbolP);
  1327.             }
  1328.           else
  1329.             {
  1330.               expressionP->X_op = O_symbol;
  1331.               expressionP->X_add_symbol = symbolP;
  1332.               expressionP->X_add_number = 0;
  1333.             }
  1334.  
  1335.           restore_line_pointer (c);
  1336.         }
  1337.       else
  1338.         {
  1339.           /* Let the target try to parse it.  Success is indicated by changing
  1340.              the X_op field to something other than O_absent and pointing
  1341.              input_line_pointer past the expression.  If it can't parse the
  1342.              expression, X_op and input_line_pointer should be unchanged.  */
  1343.           expressionP->X_op = O_absent;
  1344.           --input_line_pointer;
  1345.           md_operand (expressionP);
  1346.           if (expressionP->X_op == O_absent)
  1347.             {
  1348.               ++input_line_pointer;
  1349.               as_bad (_("bad expression"));
  1350.               expressionP->X_op = O_constant;
  1351.               expressionP->X_add_number = 0;
  1352.             }
  1353.         }
  1354.       break;
  1355.     }
  1356.  
  1357.   /* It is more 'efficient' to clean up the expressionS when they are
  1358.      created.  Doing it here saves lines of code.  */
  1359.   clean_up_expression (expressionP);
  1360.   SKIP_WHITESPACE ();           /* -> 1st char after operand.  */
  1361.   know (*input_line_pointer != ' ');
  1362.  
  1363.   /* The PA port needs this information.  */
  1364.   if (expressionP->X_add_symbol)
  1365.     symbol_mark_used (expressionP->X_add_symbol);
  1366.  
  1367.   if (mode != expr_defer)
  1368.     {
  1369.       expressionP->X_add_symbol
  1370.         = symbol_clone_if_forward_ref (expressionP->X_add_symbol);
  1371.       expressionP->X_op_symbol
  1372.         = symbol_clone_if_forward_ref (expressionP->X_op_symbol);
  1373.     }
  1374.  
  1375.   switch (expressionP->X_op)
  1376.     {
  1377.     default:
  1378.       return absolute_section;
  1379.     case O_symbol:
  1380.       return S_GET_SEGMENT (expressionP->X_add_symbol);
  1381.     case O_register:
  1382.       return reg_section;
  1383.     }
  1384. }
  1386. /* Internal.  Simplify a struct expression for use by expr ().  */
  1387.  
  1388. /* In:  address of an expressionS.
  1389.         The X_op field of the expressionS may only take certain values.
  1390.         Elsewise we waste time special-case testing. Sigh. Ditto SEG_ABSENT.
  1391.  
  1392.    Out: expressionS may have been modified:
  1393.         Unused fields zeroed to help expr ().  */
  1394.  
  1395. static void
  1396. clean_up_expression (expressionS *expressionP)
  1397. {
  1398.   switch (expressionP->X_op)
  1399.     {
  1400.     case O_illegal:
  1401.     case O_absent:
  1402.       expressionP->X_add_number = 0;
  1403.       /* Fall through.  */
  1404.     case O_big:
  1405.     case O_constant:
  1406.     case O_register:
  1407.       expressionP->X_add_symbol = NULL;
  1408.       /* Fall through.  */
  1409.     case O_symbol:
  1410.     case O_uminus:
  1411.     case O_bit_not:
  1412.       expressionP->X_op_symbol = NULL;
  1413.       break;
  1414.     default:
  1415.       break;
  1416.     }
  1417. }
  1419. /* Expression parser.  */
  1420.  
  1421. /* We allow an empty expression, and just assume (absolute,0) silently.
  1422.    Unary operators and parenthetical expressions are treated as operands.
  1423.    As usual, Q==quantity==operand, O==operator, X==expression mnemonics.
  1424.  
  1425.    We used to do an aho/ullman shift-reduce parser, but the logic got so
  1426.    warped that I flushed it and wrote a recursive-descent parser instead.
  1427.    Now things are stable, would anybody like to write a fast parser?
  1428.    Most expressions are either register (which does not even reach here)
  1429.    or 1 symbol. Then "symbol+constant" and "symbol-symbol" are common.
  1430.    So I guess it doesn't really matter how inefficient more complex expressions
  1431.    are parsed.
  1432.  
  1433.    After expr(RANK,resultP) input_line_pointer->operator of rank <= RANK.
  1434.    Also, we have consumed any leading or trailing spaces (operand does that)
  1435.    and done all intervening operators.
  1436.  
  1437.    This returns the segment of the result, which will be
  1438.    absolute_section or the segment of a symbol.  */
  1439.  
  1440. #undef __
  1441. #define __ O_illegal
  1442. #ifndef O_SINGLE_EQ
  1443. #define O_SINGLE_EQ O_illegal
  1444. #endif
  1445.  
  1446. /* Maps ASCII -> operators.  */
  1447. static const operatorT op_encoding[256] = {
  1448.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1449.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1450.  
  1451.   __, O_bit_or_not, __, __, __, O_modulus, O_bit_and, __,
  1452.   __, __, O_multiply, O_add, __, O_subtract, __, O_divide,
  1453.   __, __, __, __, __, __, __, __,
  1454.   __, __, __, __, O_lt, O_SINGLE_EQ, O_gt, __,
  1455.   __, __, __, __, __, __, __, __,
  1456.   __, __, __, __, __, __, __, __,
  1457.   __, __, __, __, __, __, __, __,
  1458.   __, __, __,
  1459. #ifdef NEED_INDEX_OPERATOR
  1460.   O_index,
  1461. #else
  1462.   __,
  1463. #endif
  1464.   __, __, O_bit_exclusive_or, __,
  1465.   __, __, __, __, __, __, __, __,
  1466.   __, __, __, __, __, __, __, __,
  1467.   __, __, __, __, __, __, __, __,
  1468.   __, __, __, __, O_bit_inclusive_or, __, __, __,
  1469.  
  1470.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1471.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1472.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1473.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1474.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1475.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1476.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
  1477.   __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __
  1478. };
  1479.  
  1480. /* Rank Examples
  1481.    0    operand, (expression)
  1482.    1    ||
  1483.    2    &&
  1484.    3    == <> < <= >= >
  1485.    4    + -
  1486.    5    used for * / % in MRI mode
  1487.    6    & ^ ! |
  1488.    7    * / % << >>
  1489.    8    unary - unary ~
  1490. */
  1491. static operator_rankT op_rank[O_max] = {
  1492.   0,    /* O_illegal */
  1493.   0,    /* O_absent */
  1494.   0,    /* O_constant */
  1495.   0,    /* O_symbol */
  1496.   0,    /* O_symbol_rva */
  1497.   0,    /* O_register */
  1498.   0,    /* O_big */
  1499.   9,    /* O_uminus */
  1500.   9,    /* O_bit_not */
  1501.   9,    /* O_logical_not */
  1502.   8,    /* O_multiply */
  1503.   8,    /* O_divide */
  1504.   8,    /* O_modulus */
  1505.   8,    /* O_left_shift */
  1506.   8,    /* O_right_shift */
  1507.   7,    /* O_bit_inclusive_or */
  1508.   7,    /* O_bit_or_not */
  1509.   7,    /* O_bit_exclusive_or */
  1510.   7,    /* O_bit_and */
  1511.   5,    /* O_add */
  1512.   5,    /* O_subtract */
  1513.   4,    /* O_eq */
  1514.   4,    /* O_ne */
  1515.   4,    /* O_lt */
  1516.   4,    /* O_le */
  1517.   4,    /* O_ge */
  1518.   4,    /* O_gt */
  1519.   3,    /* O_logical_and */
  1520.   2,    /* O_logical_or */
  1521.   1,    /* O_index */
  1522. };
  1523.  
  1524. /* Unfortunately, in MRI mode for the m68k, multiplication and
  1525.    division have lower precedence than the bit wise operators.  This
  1526.    function sets the operator precedences correctly for the current
  1527.    mode.  Also, MRI uses a different bit_not operator, and this fixes
  1528.    that as well.  */
  1529.  
  1530. #define STANDARD_MUL_PRECEDENCE 8
  1531. #define MRI_MUL_PRECEDENCE 6
  1532.  
  1533. void
  1534. expr_set_precedence (void)
  1535. {
  1536.   if (flag_m68k_mri)
  1537.     {
  1538.       op_rank[O_multiply] = MRI_MUL_PRECEDENCE;
  1539.       op_rank[O_divide] = MRI_MUL_PRECEDENCE;
  1540.       op_rank[O_modulus] = MRI_MUL_PRECEDENCE;
  1541.     }
  1542.   else
  1543.     {
  1544.       op_rank[O_multiply] = STANDARD_MUL_PRECEDENCE;
  1545.       op_rank[O_divide] = STANDARD_MUL_PRECEDENCE;
  1546.       op_rank[O_modulus] = STANDARD_MUL_PRECEDENCE;
  1547.     }
  1548. }
  1549.  
  1550. void
  1551. expr_set_rank (operatorT op, operator_rankT rank)
  1552. {
  1553.   gas_assert (op >= O_md1 && op < ARRAY_SIZE (op_rank));
  1554.   op_rank[op] = rank;
  1555. }
  1556.  
  1557. /* Initialize the expression parser.  */
  1558.  
  1559. void
  1560. expr_begin (void)
  1561. {
  1562.   expr_set_precedence ();
  1563.  
  1564.   /* Verify that X_op field is wide enough.  */
  1565.   {
  1566.     expressionS e;
  1567.     e.X_op = O_max;
  1568.     gas_assert (e.X_op == O_max);
  1569.   }
  1570. }
  1572. /* Return the encoding for the operator at INPUT_LINE_POINTER, and
  1573.    sets NUM_CHARS to the number of characters in the operator.
  1574.    Does not advance INPUT_LINE_POINTER.  */
  1575.  
  1576. static inline operatorT
  1577. operatorf (int *num_chars)
  1578. {
  1579.   int c;
  1580.   operatorT ret;
  1581.  
  1582.   c = *input_line_pointer & 0xff;
  1583.   *num_chars = 1;
  1584.  
  1585.   if (is_end_of_line[c])
  1586.     return O_illegal;
  1587.  
  1588. #ifdef md_operator
  1589.   if (is_name_beginner (c))
  1590.     {
  1591.       char *name;
  1592.       char ec = get_symbol_name (& name);
  1593.  
  1594.       ret = md_operator (name, 2, &ec);
  1595.       switch (ret)
  1596.         {
  1597.         case O_absent:
  1598.           *input_line_pointer = ec;
  1599.           input_line_pointer = name;
  1600.           break;
  1601.         case O_uminus:
  1602.         case O_bit_not:
  1603.         case O_logical_not:
  1604.           as_bad (_("invalid use of operator \"%s\""), name);
  1605.           ret = O_illegal;
  1606.           /* FALLTHROUGH */
  1607.         default:
  1608.           *input_line_pointer = ec;
  1609.           *num_chars = input_line_pointer - name;
  1610.           input_line_pointer = name;
  1611.           return ret;
  1612.         }
  1613.     }
  1614. #endif
  1615.  
  1616.   switch (c)
  1617.     {
  1618.     default:
  1619.       ret = op_encoding[c];
  1620. #ifdef md_operator
  1621.       if (ret == O_illegal)
  1622.         {
  1623.           char *start = input_line_pointer;
  1624.  
  1625.           ret = md_operator (NULL, 2, NULL);
  1626.           if (ret != O_illegal)
  1627.             *num_chars = input_line_pointer - start;
  1628.           input_line_pointer = start;
  1629.         }
  1630. #endif
  1631.       return ret;
  1632.  
  1633.     case '+':
  1634.     case '-':
  1635.       return op_encoding[c];
  1636.  
  1637.     case '<':
  1638.       switch (input_line_pointer[1])
  1639.         {
  1640.         default:
  1641.           return op_encoding[c];
  1642.         case '<':
  1643.           ret = O_left_shift;
  1644.           break;
  1645.         case '>':
  1646.           ret = O_ne;
  1647.           break;
  1648.         case '=':
  1649.           ret = O_le;
  1650.           break;
  1651.         }
  1652.       *num_chars = 2;
  1653.       return ret;
  1654.  
  1655.     case '=':
  1656.       if (input_line_pointer[1] != '=')
  1657.         return op_encoding[c];
  1658.  
  1659.       *num_chars = 2;
  1660.       return O_eq;
  1661.  
  1662.     case '>':
  1663.       switch (input_line_pointer[1])
  1664.         {
  1665.         default:
  1666.           return op_encoding[c];
  1667.         case '>':
  1668.           ret = O_right_shift;
  1669.           break;
  1670.         case '=':
  1671.           ret = O_ge;
  1672.           break;
  1673.         }
  1674.       *num_chars = 2;
  1675.       return ret;
  1676.  
  1677.     case '!':
  1678.       switch (input_line_pointer[1])
  1679.         {
  1680.         case '!':
  1681.           /* We accept !! as equivalent to ^ for MRI compatibility. */
  1682.           *num_chars = 2;
  1683.           return O_bit_exclusive_or;
  1684.         case '=':
  1685.           /* We accept != as equivalent to <>.  */
  1686.           *num_chars = 2;
  1687.           return O_ne;
  1688.         default:
  1689.           if (flag_m68k_mri)
  1690.             return O_bit_inclusive_or;
  1691.           return op_encoding[c];
  1692.         }
  1693.  
  1694.     case '|':
  1695.       if (input_line_pointer[1] != '|')
  1696.         return op_encoding[c];
  1697.  
  1698.       *num_chars = 2;
  1699.       return O_logical_or;
  1700.  
  1701.     case '&':
  1702.       if (input_line_pointer[1] != '&')
  1703.         return op_encoding[c];
  1704.  
  1705.       *num_chars = 2;
  1706.       return O_logical_and;
  1707.     }
  1708.  
  1709.   /* NOTREACHED  */
  1710. }
  1711.  
  1712. /* Implement "word-size + 1 bit" addition for
  1713.    {resultP->X_extrabit:resultP->X_add_number} + {rhs_highbit:amount}.  This
  1714.    is used so that the full range of unsigned word values and the full range of
  1715.    signed word values can be represented in an O_constant expression, which is
  1716.    useful e.g. for .sleb128 directives.  */
  1717.  
  1718. void
  1719. add_to_result (expressionS *resultP, offsetT amount, int rhs_highbit)
  1720. {
  1721.   valueT ures = resultP->X_add_number;
  1722.   valueT uamount = amount;
  1723.  
  1724.   resultP->X_add_number += amount;
  1725.  
  1726.   resultP->X_extrabit ^= rhs_highbit;
  1727.  
  1728.   if (ures + uamount < ures)
  1729.     resultP->X_extrabit ^= 1;
  1730. }
  1731.  
  1732. /* Similarly, for subtraction.  */
  1733.  
  1734. void
  1735. subtract_from_result (expressionS *resultP, offsetT amount, int rhs_highbit)
  1736. {
  1737.   valueT ures = resultP->X_add_number;
  1738.   valueT uamount = amount;
  1739.  
  1740.   resultP->X_add_number -= amount;
  1741.  
  1742.   resultP->X_extrabit ^= rhs_highbit;
  1743.  
  1744.   if (ures < uamount)
  1745.     resultP->X_extrabit ^= 1;
  1746. }
  1747.  
  1748. /* Parse an expression.  */
  1749.  
  1750. segT
  1751. expr (int rankarg,              /* Larger # is higher rank.  */
  1752.       expressionS *resultP,     /* Deliver result here.  */
  1753.       enum expr_mode mode       /* Controls behavior.  */)
  1754. {
  1755.   operator_rankT rank = (operator_rankT) rankarg;
  1756.   segT retval;
  1757.   expressionS right;
  1758.   operatorT op_left;
  1759.   operatorT op_right;
  1760.   int op_chars;
  1761.  
  1762.   know (rankarg >= 0);
  1763.  
  1764.   /* Save the value of dot for the fixup code.  */
  1765.   if (rank == 0)
  1766.     {
  1767.       dot_value = frag_now_fix ();
  1768.       dot_frag = frag_now;
  1769.     }
  1770.  
  1771.   retval = operand (resultP, mode);
  1772.  
  1773.   /* operand () gobbles spaces.  */
  1774.   know (*input_line_pointer != ' ');
  1775.  
  1776.   op_left = operatorf (&op_chars);
  1777.   while (op_left != O_illegal && op_rank[(int) op_left] > rank)
  1778.     {
  1779.       segT rightseg;
  1780.       offsetT frag_off;
  1781.  
  1782.       input_line_pointer += op_chars;   /* -> after operator.  */
  1783.  
  1784.       right.X_md = 0;
  1785.       rightseg = expr (op_rank[(int) op_left], &right, mode);
  1786.       if (right.X_op == O_absent)
  1787.         {
  1788.           as_warn (_("missing operand; zero assumed"));
  1789.           right.X_op = O_constant;
  1790.           right.X_add_number = 0;
  1791.           right.X_add_symbol = NULL;
  1792.           right.X_op_symbol = NULL;
  1793.         }
  1794.  
  1795.       know (*input_line_pointer != ' ');
  1796.  
  1797.       if (op_left == O_index)
  1798.         {
  1799.           if (*input_line_pointer != ']')
  1800.             as_bad ("missing right bracket");
  1801.           else
  1802.             {
  1803.               ++input_line_pointer;
  1804.               SKIP_WHITESPACE ();
  1805.             }
  1806.         }
  1807.  
  1808.       op_right = operatorf (&op_chars);
  1809.  
  1810.       know (op_right == O_illegal || op_left == O_index
  1811.             || op_rank[(int) op_right] <= op_rank[(int) op_left]);
  1812.       know ((int) op_left >= (int) O_multiply);
  1813. #ifndef md_operator
  1814.       know ((int) op_left <= (int) O_index);
  1815. #else
  1816.       know ((int) op_left < (int) O_max);
  1817. #endif
  1818.  
  1819.       /* input_line_pointer->after right-hand quantity.  */
  1820.       /* left-hand quantity in resultP.  */
  1821.       /* right-hand quantity in right.  */
  1822.       /* operator in op_left.  */
  1823.  
  1824.       if (resultP->X_op == O_big)
  1825.         {
  1826.           if (resultP->X_add_number > 0)
  1827.             as_warn (_("left operand is a bignum; integer 0 assumed"));
  1828.           else
  1829.             as_warn (_("left operand is a float; integer 0 assumed"));
  1830.           resultP->X_op = O_constant;
  1831.           resultP->X_add_number = 0;
  1832.           resultP->X_add_symbol = NULL;
  1833.           resultP->X_op_symbol = NULL;
  1834.         }
  1835.       if (right.X_op == O_big)
  1836.         {
  1837.           if (right.X_add_number > 0)
  1838.             as_warn (_("right operand is a bignum; integer 0 assumed"));
  1839.           else
  1840.             as_warn (_("right operand is a float; integer 0 assumed"));
  1841.           right.X_op = O_constant;
  1842.           right.X_add_number = 0;
  1843.           right.X_add_symbol = NULL;
  1844.           right.X_op_symbol = NULL;
  1845.         }
  1846.  
  1847.       /* Optimize common cases.  */
  1848. #ifdef md_optimize_expr
  1849.       if (md_optimize_expr (resultP, op_left, &right))
  1850.         {
  1851.           /* Skip.  */
  1852.           ;
  1853.         }
  1854.       else
  1855. #endif
  1856. #ifndef md_register_arithmetic
  1857. # define md_register_arithmetic 1
  1858. #endif
  1859.       if (op_left == O_add && right.X_op == O_constant
  1860.           && (md_register_arithmetic || resultP->X_op != O_register))
  1861.         {
  1862.           /* X + constant.  */
  1863.           add_to_result (resultP, right.X_add_number, right.X_extrabit);
  1864.         }
  1865.       /* This case comes up in PIC code.  */
  1866.       else if (op_left == O_subtract
  1867.                && right.X_op == O_symbol
  1868.                && resultP->X_op == O_symbol
  1869.                && retval == rightseg
  1870. #ifdef md_allow_local_subtract
  1871.                && md_allow_local_subtract (resultP, & right, rightseg)
  1872. #endif
  1873.                && ((SEG_NORMAL (rightseg)
  1874.                     && !S_FORCE_RELOC (resultP->X_add_symbol, 0)
  1875.                     && !S_FORCE_RELOC (right.X_add_symbol, 0))
  1876.                    || right.X_add_symbol == resultP->X_add_symbol)
  1877.                && frag_offset_fixed_p (symbol_get_frag (resultP->X_add_symbol),
  1878.                                        symbol_get_frag (right.X_add_symbol),
  1879.                                        &frag_off))
  1880.         {
  1881.           offsetT symval_diff = S_GET_VALUE (resultP->X_add_symbol)
  1882.                                 - S_GET_VALUE (right.X_add_symbol);
  1883.           subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
  1884.           subtract_from_result (resultP, frag_off / OCTETS_PER_BYTE, 0);
  1885.           add_to_result (resultP, symval_diff, symval_diff < 0);
  1886.           resultP->X_op = O_constant;
  1887.           resultP->X_add_symbol = 0;
  1888.         }
  1889.       else if (op_left == O_subtract && right.X_op == O_constant
  1890.                && (md_register_arithmetic || resultP->X_op != O_register))
  1891.         {
  1892.           /* X - constant.  */
  1893.           subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
  1894.         }
  1895.       else if (op_left == O_add && resultP->X_op == O_constant
  1896.                && (md_register_arithmetic || right.X_op != O_register))
  1897.         {
  1898.           /* Constant + X.  */
  1899.           resultP->X_op = right.X_op;
  1900.           resultP->X_add_symbol = right.X_add_symbol;
  1901.           resultP->X_op_symbol = right.X_op_symbol;
  1902.           add_to_result (resultP, right.X_add_number, right.X_extrabit);
  1903.           retval = rightseg;
  1904.         }
  1905.       else if (resultP->X_op == O_constant && right.X_op == O_constant)
  1906.         {
  1907.           /* Constant OP constant.  */
  1908.           offsetT v = right.X_add_number;
  1909.           if (v == 0 && (op_left == O_divide || op_left == O_modulus))
  1910.             {
  1911.               as_warn (_("division by zero"));
  1912.               v = 1;
  1913.             }
  1914.           if ((valueT) v >= sizeof(valueT) * CHAR_BIT
  1915.               && (op_left == O_left_shift || op_left == O_right_shift))
  1916.             {
  1917.               as_warn_value_out_of_range (_("shift count"), v, 0,
  1918.                                           sizeof(valueT) * CHAR_BIT - 1,
  1919.                                           NULL, 0);
  1920.               resultP->X_add_number = v = 0;
  1921.             }
  1922.           switch (op_left)
  1923.             {
  1924.             default:                    goto general;
  1925.             case O_multiply:            resultP->X_add_number *= v; break;
  1926.             case O_divide:              resultP->X_add_number /= v; break;
  1927.             case O_modulus:             resultP->X_add_number %= v; break;
  1928.             case O_left_shift:          resultP->X_add_number <<= v; break;
  1929.             case O_right_shift:
  1930.               /* We always use unsigned shifts, to avoid relying on
  1931.                  characteristics of the compiler used to compile gas.  */
  1932.               resultP->X_add_number =
  1933.                 (offsetT) ((valueT) resultP->X_add_number >> (valueT) v);
  1934.               break;
  1935.             case O_bit_inclusive_or:    resultP->X_add_number |= v; break;
  1936.             case O_bit_or_not:          resultP->X_add_number |= ~v; break;
  1937.             case O_bit_exclusive_or:    resultP->X_add_number ^= v; break;
  1938.             case O_bit_and:             resultP->X_add_number &= v; break;
  1939.               /* Constant + constant (O_add) is handled by the
  1940.                  previous if statement for constant + X, so is omitted
  1941.                  here.  */
  1942.             case O_subtract:
  1943.               subtract_from_result (resultP, v, 0);
  1944.               break;
  1945.             case O_eq:
  1946.               resultP->X_add_number =
  1947.                 resultP->X_add_number == v ? ~ (offsetT) 0 : 0;
  1948.               break;
  1949.             case O_ne:
  1950.               resultP->X_add_number =
  1951.                 resultP->X_add_number != v ? ~ (offsetT) 0 : 0;
  1952.               break;
  1953.             case O_lt:
  1954.               resultP->X_add_number =
  1955.                 resultP->X_add_number <  v ? ~ (offsetT) 0 : 0;
  1956.               break;
  1957.             case O_le:
  1958.               resultP->X_add_number =
  1959.                 resultP->X_add_number <= v ? ~ (offsetT) 0 : 0;
  1960.               break;
  1961.             case O_ge:
  1962.               resultP->X_add_number =
  1963.                 resultP->X_add_number >= v ? ~ (offsetT) 0 : 0;
  1964.               break;
  1965.             case O_gt:
  1966.               resultP->X_add_number =
  1967.                 resultP->X_add_number >  v ? ~ (offsetT) 0 : 0;
  1968.               break;
  1969.             case O_logical_and:
  1970.               resultP->X_add_number = resultP->X_add_number && v;
  1971.               break;
  1972.             case O_logical_or:
  1973.               resultP->X_add_number = resultP->X_add_number || v;
  1974.               break;
  1975.             }
  1976.         }
  1977.       else if (resultP->X_op == O_symbol
  1978.                && right.X_op == O_symbol
  1979.                && (op_left == O_add
  1980.                    || op_left == O_subtract
  1981.                    || (resultP->X_add_number == 0
  1982.                        && right.X_add_number == 0)))
  1983.         {
  1984.           /* Symbol OP symbol.  */
  1985.           resultP->X_op = op_left;
  1986.           resultP->X_op_symbol = right.X_add_symbol;
  1987.           if (op_left == O_add)
  1988.             add_to_result (resultP, right.X_add_number, right.X_extrabit);
  1989.           else if (op_left == O_subtract)
  1990.             {
  1991.               subtract_from_result (resultP, right.X_add_number,
  1992.                                     right.X_extrabit);
  1993.               if (retval == rightseg
  1994.                   && SEG_NORMAL (retval)
  1995.                   && !S_FORCE_RELOC (resultP->X_add_symbol, 0)
  1996.                   && !S_FORCE_RELOC (right.X_add_symbol, 0))
  1997.                 {
  1998.                   retval = absolute_section;
  1999.                   rightseg = absolute_section;
  2000.                 }
  2001.             }
  2002.         }
  2003.       else
  2004.         {
  2005.         general:
  2006.           /* The general case.  */
  2007.           resultP->X_add_symbol = make_expr_symbol (resultP);
  2008.           resultP->X_op_symbol = make_expr_symbol (&right);
  2009.           resultP->X_op = op_left;
  2010.           resultP->X_add_number = 0;
  2011.           resultP->X_unsigned = 1;
  2012.           resultP->X_extrabit = 0;
  2013.         }
  2014.  
  2015.       if (retval != rightseg)
  2016.         {
  2017.           if (retval == undefined_section)
  2018.             ;
  2019.           else if (rightseg == undefined_section)
  2020.             retval = rightseg;
  2021.           else if (retval == expr_section)
  2022.             ;
  2023.           else if (rightseg == expr_section)
  2024.             retval = rightseg;
  2025.           else if (retval == reg_section)
  2026.             ;
  2027.           else if (rightseg == reg_section)
  2028.             retval = rightseg;
  2029.           else if (rightseg == absolute_section)
  2030.             ;
  2031.           else if (retval == absolute_section)
  2032.             retval = rightseg;
  2033. #ifdef DIFF_EXPR_OK
  2034.           else if (op_left == O_subtract)
  2035.             ;
  2036. #endif
  2037.           else
  2038.             as_bad (_("operation combines symbols in different segments"));
  2039.         }
  2040.  
  2041.       op_left = op_right;
  2042.     }                           /* While next operator is >= this rank.  */
  2043.  
  2044.   /* The PA port needs this information.  */
  2045.   if (resultP->X_add_symbol)
  2046.     symbol_mark_used (resultP->X_add_symbol);
  2047.  
  2048.   if (rank == 0 && mode == expr_evaluate)
  2049.     resolve_expression (resultP);
  2050.  
  2051.   return resultP->X_op == O_constant ? absolute_section : retval;
  2052. }
  2053.  
  2054. /* Resolve an expression without changing any symbols/sub-expressions
  2055.    used.  */
  2056.  
  2057. int
  2058. resolve_expression (expressionS *expressionP)
  2059. {
  2060.   /* Help out with CSE.  */
  2061.   valueT final_val = expressionP->X_add_number;
  2062.   symbolS *add_symbol = expressionP->X_add_symbol;
  2063.   symbolS *orig_add_symbol = add_symbol;
  2064.   symbolS *op_symbol = expressionP->X_op_symbol;
  2065.   operatorT op = expressionP->X_op;
  2066.   valueT left, right;
  2067.   segT seg_left, seg_right;
  2068.   fragS *frag_left, *frag_right;
  2069.   offsetT frag_off;
  2070.  
  2071.   switch (op)
  2072.     {
  2073.     default:
  2074.       return 0;
  2075.  
  2076.     case O_constant:
  2077.     case O_register:
  2078.       left = 0;
  2079.       break;
  2080.  
  2081.     case O_symbol:
  2082.     case O_symbol_rva:
  2083.       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
  2084.         return 0;
  2085.  
  2086.       break;
  2087.  
  2088.     case O_uminus:
  2089.     case O_bit_not:
  2090.     case O_logical_not:
  2091.       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
  2092.         return 0;
  2093.  
  2094.       if (seg_left != absolute_section)
  2095.         return 0;
  2096.  
  2097.       if (op == O_logical_not)
  2098.         left = !left;
  2099.       else if (op == O_uminus)
  2100.         left = -left;
  2101.       else
  2102.         left = ~left;
  2103.       op = O_constant;
  2104.       break;
  2105.  
  2106.     case O_multiply:
  2107.     case O_divide:
  2108.     case O_modulus:
  2109.     case O_left_shift:
  2110.     case O_right_shift:
  2111.     case O_bit_inclusive_or:
  2112.     case O_bit_or_not:
  2113.     case O_bit_exclusive_or:
  2114.     case O_bit_and:
  2115.     case O_add:
  2116.     case O_subtract:
  2117.     case O_eq:
  2118.     case O_ne:
  2119.     case O_lt:
  2120.     case O_le:
  2121.     case O_ge:
  2122.     case O_gt:
  2123.     case O_logical_and:
  2124.     case O_logical_or:
  2125.       if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left)
  2126.           || !snapshot_symbol (&op_symbol, &right, &seg_right, &frag_right))
  2127.         return 0;
  2128.  
  2129.       /* Simplify addition or subtraction of a constant by folding the
  2130.          constant into X_add_number.  */
  2131.       if (op == O_add)
  2132.         {
  2133.           if (seg_right == absolute_section)
  2134.             {
  2135.               final_val += right;
  2136.               op = O_symbol;
  2137.               break;
  2138.             }
  2139.           else if (seg_left == absolute_section)
  2140.             {
  2141.               final_val += left;
  2142.               left = right;
  2143.               seg_left = seg_right;
  2144.               add_symbol = op_symbol;
  2145.               orig_add_symbol = expressionP->X_op_symbol;
  2146.               op = O_symbol;
  2147.               break;
  2148.             }
  2149.         }
  2150.       else if (op == O_subtract)
  2151.         {
  2152.           if (seg_right == absolute_section)
  2153.             {
  2154.               final_val -= right;
  2155.               op = O_symbol;
  2156.               break;
  2157.             }
  2158.         }
  2159.  
  2160.       /* Equality and non-equality tests are permitted on anything.
  2161.          Subtraction, and other comparison operators are permitted if
  2162.          both operands are in the same section.
  2163.          Shifts by constant zero are permitted on anything.
  2164.          Multiplies, bit-ors, and bit-ands with constant zero are
  2165.          permitted on anything.
  2166.          Multiplies and divides by constant one are permitted on
  2167.          anything.
  2168.          Binary operations with both operands being the same register
  2169.          or undefined symbol are permitted if the result doesn't depend
  2170.          on the input value.
  2171.          Otherwise, both operands must be absolute.  We already handled
  2172.          the case of addition or subtraction of a constant above.  */
  2173.       frag_off = 0;
  2174.       if (!(seg_left == absolute_section
  2175.                && seg_right == absolute_section)
  2176.           && !(op == O_eq || op == O_ne)
  2177.           && !((op == O_subtract
  2178.                 || op == O_lt || op == O_le || op == O_ge || op == O_gt)
  2179.                && seg_left == seg_right
  2180.                && (finalize_syms
  2181.                    || frag_offset_fixed_p (frag_left, frag_right, &frag_off))
  2182.                && (seg_left != reg_section || left == right)
  2183.                && (seg_left != undefined_section || add_symbol == op_symbol)))
  2184.         {
  2185.           if ((seg_left == absolute_section && left == 0)
  2186.               || (seg_right == absolute_section && right == 0))
  2187.             {
  2188.               if (op == O_bit_exclusive_or || op == O_bit_inclusive_or)
  2189.                 {
  2190.                   if (!(seg_right == absolute_section && right == 0))
  2191.                     {
  2192.                       seg_left = seg_right;
  2193.                       left = right;
  2194.                       add_symbol = op_symbol;
  2195.                       orig_add_symbol = expressionP->X_op_symbol;
  2196.                     }
  2197.                   op = O_symbol;
  2198.                   break;
  2199.                 }
  2200.               else if (op == O_left_shift || op == O_right_shift)
  2201.                 {
  2202.                   if (!(seg_left == absolute_section && left == 0))
  2203.                     {
  2204.                       op = O_symbol;
  2205.                       break;
  2206.                     }
  2207.                 }
  2208.               else if (op != O_multiply
  2209.                        && op != O_bit_or_not && op != O_bit_and)
  2210.                 return 0;
  2211.             }
  2212.           else if (op == O_multiply
  2213.                    && seg_left == absolute_section && left == 1)
  2214.             {
  2215.               seg_left = seg_right;
  2216.               left = right;
  2217.               add_symbol = op_symbol;
  2218.               orig_add_symbol = expressionP->X_op_symbol;
  2219.               op = O_symbol;
  2220.               break;
  2221.             }
  2222.           else if ((op == O_multiply || op == O_divide)
  2223.                    && seg_right == absolute_section && right == 1)
  2224.             {
  2225.               op = O_symbol;
  2226.               break;
  2227.             }
  2228.           else if (!(left == right
  2229.                      && ((seg_left == reg_section && seg_right == reg_section)
  2230.                          || (seg_left == undefined_section
  2231.                              && seg_right == undefined_section
  2232.                              && add_symbol == op_symbol))))
  2233.             return 0;
  2234.           else if (op == O_bit_and || op == O_bit_inclusive_or)
  2235.             {
  2236.               op = O_symbol;
  2237.               break;
  2238.             }
  2239.           else if (op != O_bit_exclusive_or && op != O_bit_or_not)
  2240.             return 0;
  2241.         }
  2242.  
  2243.       right += frag_off / OCTETS_PER_BYTE;
  2244.       switch (op)
  2245.         {
  2246.         case O_add:                     left += right; break;
  2247.         case O_subtract:                left -= right; break;
  2248.         case O_multiply:                left *= right; break;
  2249.         case O_divide:
  2250.           if (right == 0)
  2251.             return 0;
  2252.           left = (offsetT) left / (offsetT) right;
  2253.           break;
  2254.         case O_modulus:
  2255.           if (right == 0)
  2256.             return 0;
  2257.           left = (offsetT) left % (offsetT) right;
  2258.           break;
  2259.         case O_left_shift:              left <<= right; break;
  2260.         case O_right_shift:             left >>= right; break;
  2261.         case O_bit_inclusive_or:        left |= right; break;
  2262.         case O_bit_or_not:              left |= ~right; break;
  2263.         case O_bit_exclusive_or:        left ^= right; break;
  2264.         case O_bit_and:                 left &= right; break;
  2265.         case O_eq:
  2266.         case O_ne:
  2267.           left = (left == right
  2268.                   && seg_left == seg_right
  2269.                   && (finalize_syms || frag_left == frag_right)
  2270.                   && (seg_left != undefined_section
  2271.                       || add_symbol == op_symbol)
  2272.                   ? ~ (valueT) 0 : 0);
  2273.           if (op == O_ne)
  2274.             left = ~left;
  2275.           break;
  2276.         case O_lt:
  2277.           left = (offsetT) left <  (offsetT) right ? ~ (valueT) 0 : 0;
  2278.           break;
  2279.         case O_le:
  2280.           left = (offsetT) left <= (offsetT) right ? ~ (valueT) 0 : 0;
  2281.           break;
  2282.         case O_ge:
  2283.           left = (offsetT) left >= (offsetT) right ? ~ (valueT) 0 : 0;
  2284.           break;
  2285.         case O_gt:
  2286.           left = (offsetT) left >  (offsetT) right ? ~ (valueT) 0 : 0;
  2287.           break;
  2288.         case O_logical_and:     left = left && right; break;
  2289.         case O_logical_or:      left = left || right; break;
  2290.         default:                abort ();
  2291.         }
  2292.  
  2293.       op = O_constant;
  2294.       break;
  2295.     }
  2296.  
  2297.   if (op == O_symbol)
  2298.     {
  2299.       if (seg_left == absolute_section)
  2300.         op = O_constant;
  2301.       else if (seg_left == reg_section && final_val == 0)
  2302.         op = O_register;
  2303.       else if (!symbol_same_p (add_symbol, orig_add_symbol))
  2304.         final_val += left;
  2305.       expressionP->X_add_symbol = add_symbol;
  2306.     }
  2307.   expressionP->X_op = op;
  2308.  
  2309.   if (op == O_constant || op == O_register)
  2310.     final_val += left;
  2311.   expressionP->X_add_number = final_val;
  2312.  
  2313.   return 1;
  2314. }
  2316. /* This lives here because it belongs equally in expr.c & read.c.
  2317.    expr.c is just a branch office read.c anyway, and putting it
  2318.    here lessens the crowd at read.c.
  2319.  
  2320.    Assume input_line_pointer is at start of symbol name, or the
  2321.     start of a double quote enclosed symbol name.
  2322.    Advance input_line_pointer past symbol name.
  2323.    Turn that character into a '\0', returning its former value,
  2324.     which may be the closing double quote.
  2325.    This allows a string compare (RMS wants symbol names to be strings)
  2326.    of the symbol name.
  2327.    There will always be a char following symbol name, because all good
  2328.    lines end in end-of-line.  */
  2329.  
  2330. char
  2331. get_symbol_name (char ** ilp_return)
  2332. {
  2333.   char c;
  2334.  
  2335.   * ilp_return = input_line_pointer;
  2336.   /* We accept \001 in a name in case this is being called with a
  2337.      constructed string.  */
  2338.   if (is_name_beginner (c = *input_line_pointer++) || c == '\001')
  2339.     {
  2340.       while (is_part_of_name (c = *input_line_pointer++)
  2341.              || c == '\001')
  2342.         ;
  2343.       if (is_name_ender (c))
  2344.         c = *input_line_pointer++;
  2345.     }
  2346.   else if (c == '"')
  2347.     {
  2348.       bfd_boolean backslash_seen;
  2349.  
  2350.       * ilp_return = input_line_pointer;
  2351.       do
  2352.         {
  2353.           backslash_seen = c == '\\';
  2354.           c = * input_line_pointer ++;
  2355.         }
  2356.       while (c != 0 && (c != '"' || backslash_seen));
  2357.  
  2358.       if (c == 0)
  2359.         as_warn (_("missing closing '\"'"));
  2360.     }
  2361.   *--input_line_pointer = 0;
  2362.   return c;
  2363. }
  2364.  
  2365. /* Replace the NUL character pointed to by input_line_pointer
  2366.    with C.  If C is \" then advance past it.  Return the character
  2367.    now pointed to by input_line_pointer.  */
  2368.  
  2369. char
  2370. restore_line_pointer (char c)
  2371. {
  2372.   * input_line_pointer = c;
  2373.   if (c == '"')
  2374.     c = * ++ input_line_pointer;
  2375.   return c;
  2376. }
  2377.  
  2378. unsigned int
  2379. get_single_number (void)
  2380. {
  2381.   expressionS exp;
  2382.   operand (&exp, expr_normal);
  2383.   return exp.X_add_number;
  2384. }
  2385.