1 /* expr.c -operands, expressions-
2 Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
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 2, or (at your option)
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.
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
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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.
35 static void clean_up_expression(expressionS *expressionP);
37 static void clean_up_expression(); /* Internal. */
38 #endif /* not __STDC__ */
39 extern const char EXP_CHARS[]; /* JF hide MD floating pt stuff all the same place */
40 extern const char FLT_CHARS[];
43 * Build any floating-point literal here.
44 * Also build any bignum literal here.
47 /* LITTLENUM_TYPE generic_buffer [6]; */ /* JF this is a hack */
48 /* Seems atof_machine can backscan through generic_bignum and hit whatever
49 happens to be loaded before it in memory. And its way too complicated
50 for me to fix right. Thus a hack. JF: Just make generic_bignum bigger,
51 and never write into the early words, thus they'll always be zero.
52 I hate Dean's floating-point code. Bleh.
54 LITTLENUM_TYPE generic_bignum [SIZE_OF_LARGE_NUMBER+6];
55 FLONUM_TYPE generic_floating_point_number =
57 & generic_bignum [6], /* low (JF: Was 0) */
58 & generic_bignum [SIZE_OF_LARGE_NUMBER+6 - 1], /* high JF: (added +6) */
63 /* If nonzero, we've been asked to assemble nan, +inf or -inf */
64 int generic_floating_point_magic;
66 floating_constant(expressionP)
67 expressionS *expressionP;
69 /* input_line_pointer->*/
70 /* floating-point constant. */
73 error_code = atof_generic
74 (& input_line_pointer, ".", EXP_CHARS,
75 & generic_floating_point_number);
79 if (error_code == ERROR_EXPONENT_OVERFLOW)
81 as_bad("bad floating-point constant: exponent overflow, probably assembling junk");
85 as_bad("bad floating-point constant: unknown error code=%d.", error_code);
88 expressionP->X_seg = SEG_BIG;
89 /* input_line_pointer->just after constant, */
90 /* which may point to whitespace. */
91 expressionP->X_add_number =-1;
97 integer_constant(radix, expressionP)
99 expressionS *expressionP;
101 register char * digit_2; /*->2nd digit of number. */
104 register valueT number; /* offset or (absolute) value */
105 register short int digit; /* value of next digit in current radix */
106 register short int maxdig = 0; /* highest permitted digit value. */
107 register int too_many_digits = 0; /* if we see >= this number of */
108 register char *name; /* points to name of symbol */
109 register symbolS * symbolP; /* points to symbol */
111 int small; /* true if fits in 32 bits. */
112 extern char hex_value[]; /* in hex_value.c */
114 /* may be bignum, or may fit in 32 bits. */
116 * most numbers fit into 32 bits, and we want this case to be fast.
117 * so we pretend it will fit into 32 bits. if, after making up a 32
118 * bit number, we realise that we have scanned more digits than
119 * comfortably fit into 32 bits, we re-scan the digits coding
120 * them into a bignum. for decimal and octal numbers we are conservative: some
121 * numbers may be assumed bignums when in fact they do fit into 32 bits.
122 * numbers of any radix can have excess leading zeros: we strive
123 * to recognise this and cast them back into 32 bits.
124 * we must check that the bignum really is more than 32
125 * bits, and change it back to a 32-bit number if it fits.
126 * the number we are looking for is expected to be positive, but
127 * if it fits into 32 bits as an unsigned number, we let it be a 32-bit
128 * number. the cavalier approach is for speed in ordinary cases.
136 too_many_digits = 33;
140 too_many_digits = 11;
150 too_many_digits = 11;
152 c = *input_line_pointer;
153 input_line_pointer++;
154 digit_2 = input_line_pointer;
155 for (number=0; (digit=hex_value[c])<maxdig; c = * input_line_pointer ++)
157 number = number * radix + digit;
159 /* c contains character after number. */
160 /* input_line_pointer->char after c. */
161 small = input_line_pointer - digit_2 < too_many_digits;
165 * we saw a lot of digits. manufacture a bignum the hard way.
167 LITTLENUM_TYPE * leader; /*->high order littlenum of the bignum. */
168 LITTLENUM_TYPE * pointer; /*->littlenum we are frobbing now. */
171 leader = generic_bignum;
172 generic_bignum [0] = 0;
173 generic_bignum [1] = 0;
174 /* we could just use digit_2, but lets be mnemonic. */
175 input_line_pointer = --digit_2; /*->1st digit. */
176 c = *input_line_pointer++;
177 for (; (carry = hex_value[c]) < maxdig; c = *input_line_pointer++)
179 for (pointer = generic_bignum;
185 work = carry + radix * * pointer;
186 *pointer = work & LITTLENUM_MASK;
187 carry = work >> LITTLENUM_NUMBER_OF_BITS;
191 if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1)
192 { /* room to grow a longer bignum. */
197 /* again, c is char after number, */
198 /* input_line_pointer->after c. */
199 know(sizeof (int) * 8 == 32);
200 know(LITTLENUM_NUMBER_OF_BITS == 16);
201 /* hence the constant "2" in the next line. */
202 if (leader < generic_bignum + 2)
203 { /* will fit into 32 bits. */
205 ((generic_bignum [1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS)
206 | (generic_bignum [0] & LITTLENUM_MASK);
211 number = leader - generic_bignum + 1; /* number of littlenums in the bignum. */
216 * here with number, in correct radix. c is the next char.
217 * note that unlike un*x, we allow "011f" "0x9f" to
218 * both mean the same as the (conventional) "9f". this is simply easier
219 * than checking for strict canonical form. syntax sux!
224 #ifdef LOCAL_LABELS_FB
227 * backward ref to local label.
228 * because it is backward, expect it to be defined.
231 * construct a local label.
233 name = fb_label_name((int) number, 0);
235 /* seen before, or symbol is defined: ok */
236 symbolP = symbol_find(name);
237 if ((symbolP != NULL) && (S_IS_DEFINED(symbolP))) {
239 /* local labels are never absolute. don't waste time checking absoluteness. */
240 know(SEG_NORMAL(S_GET_SEGMENT(symbolP)));
242 expressionP->X_add_symbol = symbolP;
243 expressionP->X_seg = S_GET_SEGMENT(symbolP);
245 } else { /* either not seen or not defined. */
246 as_bad("backw. ref to unknown label \"%d:\", 0 assumed.", number);
247 expressionP->X_seg = SEG_ABSOLUTE;
250 expressionP->X_add_number = 0;
256 * forward reference. expect symbol to be undefined or
257 * unknown. undefined: seen it before. unknown: never seen
259 * construct a local label name, then an undefined symbol.
260 * don't create a xseg frag for it: caller may do that.
261 * just return it as never seen before.
263 name = fb_label_name((int) number, 1);
264 symbolP = symbol_find_or_make(name);
265 /* we have no need to check symbol properties. */
266 #ifndef many_segments
267 /* since "know" puts its arg into a "string", we
268 can't have newlines in the argument. */
269 know(S_GET_SEGMENT(symbolP) == SEG_UNKNOWN || S_GET_SEGMENT(symbolP) == SEG_TEXT || S_GET_SEGMENT(symbolP) == SEG_DATA);
271 expressionP->X_add_symbol = symbolP;
272 expressionP->X_seg = SEG_UNKNOWN;
273 expressionP->X_subtract_symbol = NULL;
274 expressionP->X_add_number = 0;
279 #endif /* LOCAL_LABELS_FB */
281 #ifdef LOCAL_LABELS_DOLLAR
285 /* if the dollar label is *currently* defined, then this is just another
286 reference to it. If it is not *currently* defined, then this is a
287 fresh instantiation of that number, so create it. */
289 if (dollar_label_defined(number)) {
290 name = dollar_label_name(number, 0);
291 symbolP = symbol_find(name);
292 know(symbolP != NULL);
294 name = dollar_label_name(number, 1);
295 symbolP = symbol_find_or_make(name);
298 expressionP->X_add_symbol = symbolP;
299 expressionP->X_add_number = 0;
300 expressionP->X_seg = S_GET_SEGMENT(symbolP);
305 #endif /* LOCAL_LABELS_DOLLAR */
308 expressionP->X_add_number = number;
309 expressionP->X_seg = SEG_ABSOLUTE;
310 input_line_pointer--; /* restore following character. */
312 } /* really just a number */
314 } /* switch on char following the number */
317 } else { /* not a small number */
318 expressionP->X_add_number = number;
319 expressionP->X_seg = SEG_BIG;
320 input_line_pointer --; /*->char following number. */
322 } /* integer_constant() */
326 * Summary of operand().
328 * in: Input_line_pointer points to 1st char of operand, which may
331 * out: A expressionS. X_seg determines how to understand the rest of the
333 * The operand may have been empty: in this case X_seg == SEG_ABSENT.
334 * Input_line_pointer->(next non-blank) char after operand.
341 operand (expressionP)
342 register expressionS * expressionP;
345 register symbolS * symbolP; /* points to symbol */
346 register char *name; /* points to name of symbol */
347 /* invented for humans only, hope */
348 /* optimising compiler flushes it! */
349 register short int radix; /* 2, 8, 10 or 16, 0 when floating */
350 /* 0 means we saw start of a floating- */
351 /* point constant. */
353 /* digits, assume it is a bignum. */
358 SKIP_WHITESPACE(); /* leading whitespace is part of operand. */
359 c = * input_line_pointer ++; /* input_line_pointer->past char in c. */
365 integer_constant(2, expressionP);
368 integer_constant(8, expressionP);
371 integer_constant(16, expressionP);
383 input_line_pointer--;
385 integer_constant(10, expressionP);
389 /* non-decimal radix */
392 c = *input_line_pointer;
397 if (c && strchr(FLT_CHARS,c))
399 input_line_pointer++;
400 floating_constant(expressionP);
406 /* The string was only zero */
407 expressionP->X_add_symbol = 0;
408 expressionP->X_add_number = 0;
409 expressionP->X_seg = SEG_ABSOLUTE;
416 input_line_pointer++;
417 integer_constant(16, expressionP);
421 input_line_pointer++;
422 integer_constant(2, expressionP);
433 integer_constant(8, expressionP);
437 /* if it says '0f' and the line ends or it doesn't look like
438 a floating point #, its a local label ref. dtrt */
439 /* likewise for the b's. xoxorich. */
440 if ((c == 'f' || c == 'b' || c == 'b')
441 && (!*input_line_pointer ||
442 (!strchr("+-.0123456789",*input_line_pointer) &&
443 !strchr(EXP_CHARS,*input_line_pointer))))
445 input_line_pointer -= 2;
446 integer_constant(10, expressionP);
459 input_line_pointer++;
460 floating_constant(expressionP);
466 /* didn't begin with digit & not a name */
468 (void)expression(expressionP);
469 /* Expression() will pass trailing whitespace */
470 if (* input_line_pointer ++ != ')')
472 as_bad("Missing ')' assumed");
473 input_line_pointer --;
475 /* here with input_line_pointer->char after "(...)" */
477 return expressionP->X_seg;
482 * Warning: to conform to other people's assemblers NO ESCAPEMENT is permitted
483 * for a single quote. The next character, parity errors and all, is taken
484 * as the value of the operand. VERY KINKY.
486 expressionP->X_add_number = * input_line_pointer ++;
487 expressionP->X_seg = SEG_ABSOLUTE;
495 /* unary operator: hope for SEG_ABSOLUTE */
496 switch(operand (expressionP)) {
498 /* input_line_pointer -> char after operand */
501 expressionP -> X_add_number = - expressionP -> X_add_number;
503 * Notice: '-' may overflow: no warning is given. This is compatible
504 * with other people's assemblers. Sigh.
509 expressionP -> X_add_number = ~ expressionP -> X_add_number;
518 if(c=='-') { /* JF I hope this hack works */
519 expressionP->X_subtract_symbol=expressionP->X_add_symbol;
520 expressionP->X_add_symbol=0;
521 expressionP->X_seg=SEG_DIFFERENCE;
524 default: /* unary on non-absolute is unsuported */
525 as_warn("Unary operator %c ignored because bad operand follows", c);
527 /* Expression undisturbed from operand(). */
536 if( !is_part_of_name(*input_line_pointer))
538 extern struct obstack frags;
541 JF: '.' is pseudo symbol with value of current location in current
544 symbolP = symbol_new("L0\001",
546 (valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
549 expressionP->X_add_number=0;
550 expressionP->X_add_symbol=symbolP;
551 expressionP->X_seg = now_seg;
563 /* can't imagine any other kind of operand */
564 expressionP->X_seg = SEG_ABSENT;
565 input_line_pointer --;
566 md_operand (expressionP);
570 if (is_name_beginner(c)) /* here if did not begin with a digit */
573 * Identifier begins here.
574 * This is kludged for speed, so code is repeated.
577 name = -- input_line_pointer;
578 c = get_symbol_end();
579 symbolP = symbol_find_or_make(name);
581 * If we have an absolute symbol or a reg, then we know its value now.
583 expressionP->X_seg = S_GET_SEGMENT(symbolP);
584 switch (expressionP->X_seg)
588 expressionP->X_add_number = S_GET_VALUE(symbolP);
592 expressionP->X_add_number = 0;
593 expressionP->X_add_symbol = symbolP;
595 * input_line_pointer = c;
596 expressionP->X_subtract_symbol = NULL;
600 as_bad("Bad expression");
601 expressionP->X_add_number = 0;
602 expressionP->X_seg = SEG_ABSOLUTE;
615 * It is more 'efficient' to clean up the expressionS when they are created.
616 * Doing it here saves lines of code.
618 clean_up_expression (expressionP);
619 SKIP_WHITESPACE(); /*->1st char after operand. */
620 know(* input_line_pointer != ' ');
621 return (expressionP->X_seg);
625 /* Internal. Simplify a struct expression for use by expr() */
628 * In: address of a expressionS.
629 * The X_seg field of the expressionS may only take certain values.
630 * Now, we permit SEG_PASS1 to make code smaller & faster.
631 * Elsewise we waste time special-case testing. Sigh. Ditto SEG_ABSENT.
632 * Out: expressionS may have been modified:
633 * 'foo-foo' symbol references cancelled to 0,
634 * which changes X_seg from SEG_DIFFERENCE to SEG_ABSOLUTE;
635 * Unused fields zeroed to help expr().
639 clean_up_expression (expressionP)
640 register expressionS * expressionP;
642 switch (expressionP->X_seg)
646 expressionP->X_add_symbol = NULL;
647 expressionP->X_subtract_symbol = NULL;
648 expressionP->X_add_number = 0;
653 expressionP->X_subtract_symbol = NULL;
654 expressionP->X_add_symbol = NULL;
658 expressionP->X_subtract_symbol = NULL;
663 * It does not hurt to 'cancel' NULL==NULL
664 * when comparing symbols for 'eq'ness.
665 * It is faster to re-cancel them to NULL
666 * than to check for this special case.
668 if (expressionP->X_subtract_symbol == expressionP->X_add_symbol
669 || (expressionP->X_subtract_symbol
670 && expressionP->X_add_symbol
671 && expressionP->X_subtract_symbol->sy_frag==expressionP->X_add_symbol->sy_frag
672 && S_GET_VALUE(expressionP->X_subtract_symbol) == S_GET_VALUE(expressionP->X_add_symbol))) {
673 expressionP->X_subtract_symbol = NULL;
674 expressionP->X_add_symbol = NULL;
675 expressionP->X_seg = SEG_ABSOLUTE;
680 expressionP->X_add_symbol = NULL;
681 expressionP->X_subtract_symbol = NULL;
685 if (SEG_NORMAL(expressionP->X_seg)) {
686 expressionP->X_subtract_symbol = NULL;
689 BAD_CASE (expressionP->X_seg);
693 } /* clean_up_expression() */
698 * Internal. Made a function because this code is used in 2 places.
699 * Generate error or correct X_?????_symbol of expressionS.
703 * symbol_1 += symbol_2 ... well ... sort of.
707 expr_part (symbol_1_PP, symbol_2_P)
708 symbolS ** symbol_1_PP;
709 symbolS * symbol_2_P;
712 #ifndef MANY_SEGMENTS
713 know((* symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == SEG_TEXT) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_DATA) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_BSS) || (!S_IS_DEFINED(* symbol_1_PP)));
714 know(symbol_2_P == NULL || (S_GET_SEGMENT(symbol_2_P) == SEG_TEXT) || (S_GET_SEGMENT(symbol_2_P) == SEG_DATA) || (S_GET_SEGMENT(symbol_2_P) == SEG_BSS) || (!S_IS_DEFINED(symbol_2_P)));
718 if (!S_IS_DEFINED(* symbol_1_PP))
722 return_value = SEG_PASS1;
723 * symbol_1_PP = NULL;
727 know(!S_IS_DEFINED(* symbol_1_PP));
728 return_value = SEG_UNKNOWN;
735 if (!S_IS_DEFINED(symbol_2_P))
737 * symbol_1_PP = NULL;
738 return_value = SEG_PASS1;
742 /* {seg1} - {seg2} */
743 as_bad("Expression too complex, 2 symbolS forgotten: \"%s\" \"%s\"",
744 S_GET_NAME(* symbol_1_PP), S_GET_NAME(symbol_2_P));
745 * symbol_1_PP = NULL;
746 return_value = SEG_ABSOLUTE;
751 return_value = S_GET_SEGMENT(* symbol_1_PP);
756 { /* (* symbol_1_PP) == NULL */
759 * symbol_1_PP = symbol_2_P;
760 return_value = S_GET_SEGMENT(symbol_2_P);
764 * symbol_1_PP = NULL;
765 return_value = SEG_ABSOLUTE;
768 #ifndef MANY_SEGMENTS
769 know(return_value == SEG_ABSOLUTE || return_value == SEG_TEXT || return_value == SEG_DATA || return_value == SEG_BSS || return_value == SEG_UNKNOWN || return_value == SEG_PASS1);
771 know((*symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == return_value));
772 return (return_value);
775 /* Expression parser. */
778 * We allow an empty expression, and just assume (absolute,0) silently.
779 * Unary operators and parenthetical expressions are treated as operands.
780 * As usual, Q==quantity==operand, O==operator, X==expression mnemonics.
782 * We used to do a aho/ullman shift-reduce parser, but the logic got so
783 * warped that I flushed it and wrote a recursive-descent parser instead.
784 * Now things are stable, would anybody like to write a fast parser?
785 * Most expressions are either register (which does not even reach here)
786 * or 1 symbol. Then "symbol+constant" and "symbol-symbol" are common.
787 * So I guess it doesn't really matter how inefficient more complex expressions
790 * After expr(RANK,resultP) input_line_pointer->operator of rank <= RANK.
791 * Also, we have consumed any leading or trailing spaces (operand does that)
792 * and done all intervening operators.
797 O_illegal, /* (0) what we get for illegal op */
799 O_multiply, /* (1) * */
800 O_divide, /* (2) / */
801 O_modulus, /* (3) % */
802 O_left_shift, /* (4) < */
803 O_right_shift, /* (5) > */
804 O_bit_inclusive_or, /* (6) | */
805 O_bit_or_not, /* (7) ! */
806 O_bit_exclusive_or, /* (8) ^ */
807 O_bit_and, /* (9) & */
809 O_subtract /* (11) - */
815 static const operatorT op_encoding [256] = { /* maps ASCII->operators */
817 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
818 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
820 __, O_bit_or_not, __, __, __, O_modulus, O_bit_and, __,
821 __, __, O_multiply, O_add, __, O_subtract, __, O_divide,
822 __, __, __, __, __, __, __, __,
823 __, __, __, __, O_left_shift, __, O_right_shift, __,
824 __, __, __, __, __, __, __, __,
825 __, __, __, __, __, __, __, __,
826 __, __, __, __, __, __, __, __,
827 __, __, __, __, __, __, O_bit_exclusive_or, __,
828 __, __, __, __, __, __, __, __,
829 __, __, __, __, __, __, __, __,
830 __, __, __, __, __, __, __, __,
831 __, __, __, __, O_bit_inclusive_or, __, __, __,
833 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
834 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
835 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
836 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
837 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
838 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
839 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __,
840 __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __
846 * 0 operand, (expression)
851 static const operator_rankT
852 op_rank [] = { 0, 3, 3, 3, 3, 3, 2, 2, 2, 2, 1, 1 };
854 /* Return resultP->X_seg. */
855 segT expr(rank, resultP)
856 register operator_rankT rank; /* Larger # is higher rank. */
857 register expressionS *resultP; /* Deliver result here. */
860 register operatorT op_left;
861 register char c_left; /* 1st operator character. */
862 register operatorT op_right;
863 register char c_right;
866 (void)operand (resultP);
867 know(* input_line_pointer != ' '); /* Operand() gobbles spaces. */
868 c_left = * input_line_pointer; /* Potential operator character. */
869 op_left = op_encoding [c_left];
870 while (op_left != O_illegal && op_rank [(int) op_left] > rank)
872 input_line_pointer ++; /*->after 1st character of operator. */
873 /* Operators "<<" and ">>" have 2 characters. */
874 if (* input_line_pointer == c_left && (c_left == '<' || c_left == '>'))
876 input_line_pointer ++;
877 } /*->after operator. */
878 if (SEG_ABSENT == expr (op_rank[(int) op_left], &right))
880 as_warn("Missing operand value assumed absolute 0.");
881 resultP->X_add_number = 0;
882 resultP->X_subtract_symbol = NULL;
883 resultP->X_add_symbol = NULL;
884 resultP->X_seg = SEG_ABSOLUTE;
886 know(* input_line_pointer != ' ');
887 c_right = * input_line_pointer;
888 op_right = op_encoding [c_right];
889 if (* input_line_pointer == c_right && (c_right == '<' || c_right == '>'))
891 input_line_pointer ++;
892 } /*->after operator. */
893 know((int) op_right == 0 || op_rank [(int) op_right] <= op_rank[(int) op_left]);
894 /* input_line_pointer->after right-hand quantity. */
895 /* left-hand quantity in resultP */
896 /* right-hand quantity in right. */
897 /* operator in op_left. */
898 if (resultP->X_seg == SEG_PASS1 || right . X_seg == SEG_PASS1)
900 resultP->X_seg = SEG_PASS1;
904 if (resultP->X_seg == SEG_BIG)
906 as_warn("Left operand of %c is a %s. Integer 0 assumed.",
907 c_left, resultP->X_add_number > 0 ? "bignum" : "float");
908 resultP->X_seg = SEG_ABSOLUTE;
909 resultP->X_add_symbol = 0;
910 resultP->X_subtract_symbol = 0;
911 resultP->X_add_number = 0;
913 if (right . X_seg == SEG_BIG)
915 as_warn("Right operand of %c is a %s. Integer 0 assumed.",
916 c_left, right . X_add_number > 0 ? "bignum" : "float");
917 right . X_seg = SEG_ABSOLUTE;
918 right . X_add_symbol = 0;
919 right . X_subtract_symbol = 0;
920 right . X_add_number = 0;
922 if (op_left == O_subtract)
925 * Convert - into + by exchanging symbolS and negating number.
926 * I know -infinity can't be negated in 2's complement:
927 * but then it can't be subtracted either. This trick
928 * does not cause any further inaccuracy.
931 register symbolS * symbolP;
933 right . X_add_number = - right . X_add_number;
934 symbolP = right . X_add_symbol;
935 right . X_add_symbol = right . X_subtract_symbol;
936 right . X_subtract_symbol = symbolP;
939 right . X_seg = SEG_DIFFERENCE;
944 if (op_left == O_add)
948 #ifndef MANY_SEGMENTS
949 know(resultP->X_seg == SEG_DATA || resultP->X_seg == SEG_TEXT || resultP->X_seg == SEG_BSS || resultP->X_seg ==
950 SEG_UNKNOWN || resultP->X_seg == SEG_DIFFERENCE || resultP->X_seg == SEG_ABSOLUTE || resultP->X_seg == SEG_PASS1
951 || resultP->X_seg == SEG_REGISTER);
952 know(right.X_seg == SEG_DATA || right.X_seg == SEG_TEXT || right.X_seg == SEG_BSS || right.X_seg == SEG_UNKNOWN || right.X_seg == SEG_DIFFERENCE || right.X_seg == SEG_ABSOLUTE || right.X_seg == SEG_PASS1);
954 clean_up_expression (& right);
955 clean_up_expression (resultP);
957 seg1 = expr_part (& resultP->X_add_symbol, right . X_add_symbol);
958 seg2 = expr_part (& resultP->X_subtract_symbol, right . X_subtract_symbol);
959 if (seg1 == SEG_PASS1 || seg2 == SEG_PASS1) {
961 resultP->X_seg = SEG_PASS1;
962 } else if (seg2 == SEG_ABSOLUTE)
963 resultP->X_seg = seg1;
964 else if (seg1 != SEG_UNKNOWN
965 && seg1 != SEG_ABSOLUTE
966 && seg2 != SEG_UNKNOWN
968 know(seg2 != SEG_ABSOLUTE);
969 know(resultP->X_subtract_symbol);
970 #ifndef MANY_SEGMENTS
971 know(seg1 == SEG_TEXT || seg1 == SEG_DATA || seg1== SEG_BSS);
972 know(seg2 == SEG_TEXT || seg2 == SEG_DATA || seg2== SEG_BSS);
974 know(resultP->X_add_symbol);
975 know(resultP->X_subtract_symbol);
976 as_bad("Expression too complex: forgetting %s - %s",
977 S_GET_NAME(resultP->X_add_symbol),
978 S_GET_NAME(resultP->X_subtract_symbol));
979 resultP->X_seg = SEG_ABSOLUTE;
980 /* Clean_up_expression() will do the rest. */
982 resultP->X_seg = SEG_DIFFERENCE;
984 resultP->X_add_number += right . X_add_number;
985 clean_up_expression (resultP);
989 if (resultP->X_seg == SEG_UNKNOWN || right . X_seg == SEG_UNKNOWN)
991 resultP->X_seg = SEG_PASS1;
996 resultP->X_subtract_symbol = NULL;
997 resultP->X_add_symbol = NULL;
998 /* Will be SEG_ABSOLUTE. */
999 if (resultP->X_seg != SEG_ABSOLUTE || right . X_seg != SEG_ABSOLUTE)
1001 as_bad("Relocation error. Absolute 0 assumed.");
1002 resultP->X_seg = SEG_ABSOLUTE;
1003 resultP->X_add_number = 0;
1009 case O_bit_inclusive_or:
1010 resultP->X_add_number |= right . X_add_number;
1014 if (right . X_add_number)
1016 resultP->X_add_number %= right . X_add_number;
1020 as_warn("Division by 0. 0 assumed.");
1021 resultP->X_add_number = 0;
1026 resultP->X_add_number &= right . X_add_number;
1030 resultP->X_add_number *= right . X_add_number;
1034 if (right . X_add_number)
1036 resultP->X_add_number /= right . X_add_number;
1040 as_warn("Division by 0. 0 assumed.");
1041 resultP->X_add_number = 0;
1046 resultP->X_add_number <<= right . X_add_number;
1050 resultP->X_add_number >>= right . X_add_number;
1053 case O_bit_exclusive_or:
1054 resultP->X_add_number ^= right . X_add_number;
1058 resultP->X_add_number |= ~ right . X_add_number;
1064 } /* switch(operator) */
1066 } /* If we have to force need_pass_2. */
1067 } /* If operator was +. */
1068 } /* If we didn't set need_pass_2. */
1070 } /* While next operator is >= this rank. */
1071 return (resultP->X_seg);
1077 * This lives here because it belongs equally in expr.c & read.c.
1078 * Expr.c is just a branch office read.c anyway, and putting it
1079 * here lessens the crowd at read.c.
1081 * Assume input_line_pointer is at start of symbol name.
1082 * Advance input_line_pointer past symbol name.
1083 * Turn that character into a '\0', returning its former value.
1084 * This allows a string compare (RMS wants symbol names to be strings)
1085 * of the symbol name.
1086 * There will always be a char following symbol name, because all good
1087 * lines end in end-of-line.
1094 while (is_part_of_name(c = * input_line_pointer ++))
1096 * -- input_line_pointer = 0;
1101 unsigned int get_single_number()
1105 return exp.X_add_number;