439 lines
12 KiB
C
439 lines
12 KiB
C
/* symbols.c -symbol table-
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Copyright (C) 1987 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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GAS is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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GAS is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GAS; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "as.h"
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#include "hash.h"
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#include "obstack.h" /* For "symbols.h" */
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#include "struc-symbol.h"
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#include "symbols.h"
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#include "frags.h"
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#ifndef WORKING_DOT_WORD
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extern int new_broken_words;
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#endif
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#ifdef VMS
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extern char const_flag;
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#endif
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static
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struct hash_control *
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sy_hash; /* symbol-name => struct symbol pointer */
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/* Below are commented in "symbols.h". */
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unsigned int local_bss_counter;
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symbolS * symbol_rootP;
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symbolS * symbol_lastP;
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symbolS abs_symbol;
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struct obstack notes;
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symbolS * symbol_find(); /* Keep C compiler happy. */
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/*
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* Un*x idea of local labels. They are made by "n:" where n
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* is any decimal digit. Refer to them with
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* "nb" for previous (backward) n:
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* or "nf" for next (forward) n:.
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*
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* Like Un*x AS, we have one set of local label counters for entire assembly,
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* not one set per (sub)segment like in most assemblers. This implies that
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* one can refer to a label in another segment, and indeed some crufty
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* compilers have done just that.
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*
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* I document the symbol names here to save duplicating words elsewhere.
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* The mth occurence of label n: is turned into the symbol "Ln^Am" where
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* n is a digit and m is a decimal number. "L" makes it a label discarded
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* unless debugging and "^A"('\1') ensures no ordinary symbol SHOULD get the
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* same name as a local label symbol. The first "4:" is "L4^A1" - the m
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* numbers begin at 1.
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*/
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typedef short unsigned int
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local_label_countT;
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static local_label_countT
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local_label_counter[10];
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static /* Returned to caller, then copied. */
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char symbol_name_build[12]; /* used for created names ("4f") */
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#ifdef SUN_ASM_SYNTAX
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int local_label_defined[10];
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#endif
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void
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symbol_begin()
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{
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symbol_lastP = NULL;
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symbol_rootP = NULL; /* In case we have 0 symbols (!!) */
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sy_hash = hash_new();
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bzero ((char *)(& abs_symbol), sizeof(abs_symbol));
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abs_symbol . sy_type = N_ABS; /* Can't initialise a union. Sigh. */
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bzero ((char *)(local_label_counter), sizeof(local_label_counter) );
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local_bss_counter = 0;
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}
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/*
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* local_label_name()
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*
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* Caller must copy returned name: we re-use the area for the next name.
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*/
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char * /* Return local label name. */
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local_label_name(n, augend)
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register int n; /* we just saw "n:", "nf" or "nb" : n a digit */
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register int augend; /* 0 for nb, 1 for n:, nf */
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{
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register char * p;
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register char * q;
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char symbol_name_temporary[10]; /* build up a number, BACKWARDS */
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know( n >= 0 );
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know( augend == 0 || augend == 1 );
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p = symbol_name_build;
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* p ++ = 'L';
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* p ++ = n + '0'; /* Make into ASCII */
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* p ++ = 1; /* ^A */
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n = local_label_counter [ n ] + augend;
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/* version number of this local label */
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/*
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* Next code just does sprintf( {}, "%d", n);
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* It is more elegant to do the next part recursively, but a procedure
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* call for each digit emitted is considered too costly.
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*/
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q = symbol_name_temporary;
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for (*q++=0; n; q++) /* emits NOTHING if n starts as 0 */
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{
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know(n>0); /* We expect n > 0 always */
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*q = n % 10 + '0';
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n /= 10;
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}
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while ( * p ++ = * -- q )
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{
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}
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/* The label, as a '\0' ended string, starts at symbol_name_build. */
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return (symbol_name_build);
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}
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void
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local_colon (n)
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int n; /* just saw "n:" */
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{
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local_label_counter [n] ++;
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#ifdef SUN_ASM_SYNTAX
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local_label_defined[n]=1;
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#endif
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colon (local_label_name (n, 0));
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}
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/*
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* symbol_new()
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*
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* Return a pointer to a new symbol.
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* Die if we can't make a new symbol.
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* Fill in the symbol's values.
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* Add symbol to end of symbol chain.
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*
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*
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* Please always call this to create a new symbol.
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*
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* Changes since 1985: Symbol names may not contain '\0'. Sigh.
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*/
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symbolS *
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symbol_new (name, type, other, desc, value, frag)
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char * name; /* We copy this: OK to alter your copy. */
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unsigned char type; /* As in <a.out.h>. */
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char other; /* As in <a.out.h>. */
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short int desc; /* As in <a.out.h>. */
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valueT value; /* As in <a.out.h>, often an address. */
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/* Often used as offset from frag address. */
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struct frag * frag; /* For sy_frag. */
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{
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register symbolS * symbolP;
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register char * preserved_copy_of_name;
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register unsigned int name_length;
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char * p;
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name_length = strlen(name) + 1;
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obstack_grow(¬es,name,name_length);
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p=obstack_finish(¬es);
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/* obstack_1done( ¬es, name, name_length, &p ); */
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preserved_copy_of_name = p;
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p=obstack_alloc(¬es,sizeof(struct symbol));
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/* obstack_1blank( ¬es, sizeof(struct symbol), &p ); */
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symbolP = (symbolS *) p;
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symbolP -> sy_name = preserved_copy_of_name;
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symbolP -> sy_type = type;
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symbolP -> sy_other = other;
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symbolP -> sy_desc = desc;
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symbolP -> sy_value = value;
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symbolP -> sy_frag = frag;
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symbolP -> sy_next = NULL; /* End of chain. */
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symbolP -> sy_forward = NULL; /* JF */
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#ifdef SUSPECT
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symbolP -> sy_name_offset = ~ 0; /* Impossible offset catches errors. */
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symbolP -> sy_number = ~ 0; /* Ditto. */
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#endif
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/*
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* Link to end of symbol chain.
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*/
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if (symbol_lastP)
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{
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symbol_lastP -> sy_next = symbolP;
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}
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else
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{
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symbol_rootP = symbolP;
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}
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symbol_lastP = symbolP;
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return (symbolP);
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}
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/*
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* colon()
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*
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* We have just seen "<name>:".
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* Creates a struct symbol unless it already exists.
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*
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* Gripes if we are redefining a symbol incompatibly (and ignores it).
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*
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*/
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void
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colon (sym_name) /* just seen "x:" - rattle symbols & frags */
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register char * sym_name; /* symbol name, as a cannonical string */
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/* We copy this string: OK to alter later. */
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{
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register struct symbol * symbolP; /* symbol we are working with */
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#ifdef SUN_ASM_SYNTAX
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/* Sun local labes go out of scope whenever a non-local symbol is
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defined. */
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if(*sym_name !='L')
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bzero((void *)local_label_defined,sizeof(local_label_defined));
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#endif
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#ifndef WORKING_DOT_WORD
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if(new_broken_words) {
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struct broken_word *a;
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int possible_bytes;
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fragS *frag_tmp;
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char *frag_opcode;
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extern md_short_jump_size;
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extern md_long_jump_size;
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possible_bytes=md_short_jump_size+new_broken_words*md_long_jump_size;
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frag_tmp=frag_now;
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frag_opcode=frag_var(rs_broken_word,possible_bytes,possible_bytes,(relax_substateT)0,(symbolS *)broken_words,(long int)0,(char *)0);
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/* We want to store the pointer to where to insert the jump table in the
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fr_opcode of the rs_broken_word frag. This requires a little hackery */
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while(frag_tmp && (frag_tmp->fr_type!=rs_broken_word || frag_tmp->fr_opcode))
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frag_tmp=frag_tmp->fr_next;
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know(frag_tmp);
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frag_tmp->fr_opcode=frag_opcode;
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new_broken_words = 0;
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for(a=broken_words;a && a->dispfrag==0;a=a->next_broken_word)
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a->dispfrag=frag_tmp;
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}
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#endif
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if (symbolP = symbol_table_lookup( sym_name ))
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{
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#ifdef VMS
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/*
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* If the new symbol is .comm AND it has a size of zero,
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* we ignore it (i.e. the old symbol overrides it)
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*/
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if ((seg_N_TYPE [(int) now_seg] == (N_UNDF | N_EXT)) &&
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((obstack_next_free(& frags) - frag_now -> fr_literal) == 0))
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return;
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/*
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* If the old symbol is .comm and it has a size of zero,
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* we override it with the new symbol value.
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*/
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if ((symbolP -> sy_type == (N_UNDF | N_EXT)) &&
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(symbolP->sy_value == 0)) {
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symbolP -> sy_frag = frag_now;
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symbolP -> sy_other = const_flag;
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symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
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symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
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return;
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}
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#endif /* VMS */
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/*
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* Now check for undefined symbols
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*/
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if ((symbolP -> sy_type & N_TYPE) == N_UNDF)
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{
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if( symbolP -> sy_other == 0
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&& symbolP -> sy_desc == 0
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&& symbolP -> sy_value == 0)
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{
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symbolP -> sy_frag = frag_now;
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#ifdef VMS
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symbolP -> sy_other = const_flag;
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#endif
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symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
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know( N_UNDF == 0 );
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symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
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}
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else
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{
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#ifdef VMS
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/*
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* There are still several cases to check:
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* A .comm/.lcomm symbol being redefined as
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* initialized data is OK
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* A .comm/.lcomm symbol being redefined with
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* a larger size is also OK
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*/
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char New_Type = seg_N_TYPE [(int) now_seg];
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if (((symbolP->sy_type == (N_UNDF | N_EXT)) ||
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(symbolP->sy_type == N_BSS)) &&
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(((New_Type & ~N_EXT) == N_DATA) ||
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(New_Type == symbolP->sy_type))) {
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/*
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* Select which of the 2 cases this is
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*/
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if (New_Type == symbolP->sy_type) {
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/*
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* If the new size is larger we just
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* change its value. If the new size
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* is smaller, we ignore this symbol
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*/
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if (symbolP->sy_value <
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(obstack_next_free(& frags) -
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frag_now -> fr_literal)) {
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symbolP -> sy_value =
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obstack_next_free(& frags) -
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frag_now -> fr_literal;
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}
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} else {
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/*
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* It is a .comm/.lcomm being converted
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* to initialized data.
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*/
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symbolP -> sy_frag = frag_now;
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symbolP -> sy_other = const_flag;
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symbolP -> sy_value = obstack_next_free(& frags) - frag_now -> fr_literal;
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symbolP -> sy_type |= seg_N_TYPE [(int) now_seg]; /* keep N_EXT bit */
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}
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} else {
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#endif /* VMS */
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as_fatal( "Symbol \"%s\" is already defined as \"%s\"/%d.%d.%d.",
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sym_name,
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seg_name [(int) N_TYPE_seg [symbolP -> sy_type & N_TYPE]],
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symbolP -> sy_other, symbolP -> sy_desc,
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symbolP -> sy_value);
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#ifdef VMS
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}
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#endif /* VMS */
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}
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}
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else
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{
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as_fatal("Symbol %s already defined.",sym_name);
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}
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}
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else
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{
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symbolP = symbol_new (sym_name,
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(unsigned char)(seg_N_TYPE [(int) now_seg]),
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#ifdef VMS
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const_flag,
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#else
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0,
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#endif
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0,
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(valueT)(obstack_next_free(&frags)-frag_now->fr_literal),
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frag_now);
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symbol_table_insert (symbolP);
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}
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}
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/*
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* symbol_table_insert()
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*
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* Die if we can't insert the symbol.
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*
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*/
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void
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symbol_table_insert (symbolP)
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struct symbol * symbolP;
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{
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register char * error_string;
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know( symbolP );
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know( symbolP -> sy_name );
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if ( * (error_string = hash_jam (sy_hash, symbolP -> sy_name, (char *)symbolP)))
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{
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as_fatal( "Inserting \"%s\" into symbol table failed: %s",
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symbolP -> sy_name, error_string);
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}
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}
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/*
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* symbol_find_or_make()
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*
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* If a symbol name does not exist, create it as undefined, and insert
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* it into the symbol table. Return a pointer to it.
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*/
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symbolS *
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symbol_find_or_make (name)
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char * name;
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{
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register symbolS * symbolP;
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symbolP = symbol_table_lookup (name);
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if (symbolP == NULL)
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{
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symbolP = symbol_new (name, N_UNDF, 0, 0, 0, & zero_address_frag);
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symbol_table_insert (symbolP);
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}
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return (symbolP);
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}
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/*
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* symbol_find()
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*
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* Implement symbol table lookup.
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* In: A symbol's name as a string: '\0' can't be part of a symbol name.
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* Out: NULL if the name was not in the symbol table, else the address
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* of a struct symbol associated with that name.
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*/
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symbolS *
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symbol_find (name)
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char * name;
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{
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return ( (symbolS *) hash_find( sy_hash, name ));
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}
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/* end: symbols.c */
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