81 lines
1.1 KiB
C++
81 lines
1.1 KiB
C++
// The symbol table is a simple array of struct U.
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#include "stdafx.h"
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#include "defs.h"
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#define NSYM 1000
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U symtab[NSYM];
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char *printname[NSYM];
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int nsym; // number of symbols in table;
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// put symbol at index n
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void
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std_symbol(char *s, int n)
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{
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U *p;
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p = symtab + n;
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p->k = SYM;
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p->u.sym.binding = p;
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p->u.sym.binding2 = symbol(NIL);
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printname[n] = s;
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}
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// symbol lookup, create symbol if need be
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U *
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usr_symbol(char *s)
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{
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int i;
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U *p;
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for (i = 0; i < nsym; i++)
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if (strcmp(s, printname[i]) == 0)
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return symtab + i;
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if (nsym == NSYM)
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stop("symbol table overflow");
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p = symtab + nsym;
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printname[nsym] = strdup(s);
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nsym++;
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p->k = SYM;
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p->u.sym.binding = p;
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p->u.sym.binding2 = symbol(NIL);
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return p;
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}
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// get the symbol's printname
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char *
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get_printname(U *p)
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{
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int n;
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n = (int) (p - symtab);
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return printname[n];
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}
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// get symbol's index from ptr
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int
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symbol_index(U *p)
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{
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return (int) (p - symtab);
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}
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// push indexed symbol
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void
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push_symbol(int k)
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{
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push(symtab + k);
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}
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void
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clear_symbols(void)
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{
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int i;
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U *p;
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for (i = 0; i < nsym; i++) {
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p = symtab + i;
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p->u.sym.binding = p;
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p->u.sym.binding2 = symbol(NIL);
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}
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}
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