499 lines
		
	
	
	
		
			8.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			499 lines
		
	
	
	
		
			8.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
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 *
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 *          This product is part of the Amsterdam Compiler Kit.
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 *
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 * Permission to use, sell, duplicate or disclose this software must be
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 * obtained in writing. Requests for such permissions may be sent to
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 *
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 *      Dr. Andrew S. Tanenbaum
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 *      Wiskundig Seminarium
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 *      Vrije Universiteit
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 *      Postbox 7161
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 *      1007 MC Amsterdam
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 *      The Netherlands
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 *
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 */
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#ifndef NORCSID
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static char rcsid[] = "$Header$";
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#endif
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/*
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 * Decode compact EM assembly language
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 *
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 * Author: Johan Stevenson, Vrije Universiteit, Amsterdam
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 */
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#include        <stdio.h>
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#include        <assert.h>
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#include        <ctype.h>
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#include        <em_spec.h>
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#include        <em_pseu.h>
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#include        <em_flag.h>
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#include        <em_ptyp.h>
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#include        <em_mes.h>
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#define get8()          ((unsigned)getchar())
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#define check(x)        if (!(x)) fail_check()
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#define MAXSTR          256
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/*
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 * global variables
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 */
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int     opcode;
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int     offtyp;
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long    argval;
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int     dlbval;
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char    string[MAXSTR];
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int     strsiz;
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int     wsize;
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int     psize;
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int     lineno;
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int     argnum;
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int     errors;
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char    *progname;
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char    *filename;
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long    wordmask[] = {  /* allowed bits in a word */
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	0x00000000,
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	0x000000FF,
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	0x0000FFFF,
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	0x00000000,
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	0xFFFFFFFF
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};
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long    sizemask[] = {  /* allowed bits in multiples of 'wsize' */
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	0x00000000,
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	0x7FFFFFFF,
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	0x7FFFFFFE,
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	0x00000000,
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	0x7FFFFFFC
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};
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/*
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 * external tables
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 */
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extern  char    em_flag[];
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extern  short   em_ptyp[];
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extern  char    em_mnem[][4];
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extern  char    em_pseu[][4];
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/*
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 * routines
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 */
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int     get16();
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long    get32();
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main(argc,argv) char **argv; {
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	progname = argv[0];
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	if (argc >= 2) {
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		filename = argv[1];
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		if (freopen(argv[1],"r",stdin) == NULL)
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			fatal("can't open %s",argv[1]);
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	}
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	if (argc >= 3)
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		if (freopen(argv[2],"w",stdout) == NULL)
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			fatal("can't create %s",argv[2]);
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	if (get16() != sp_magic)
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		fatal("bad magic word");
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	/* In System III the array is called _ctype[] without the trailing '_' */
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	(_ctype_+1)['_'] = (_ctype_+1)['a'];
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	while (nextline())
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		;
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	return(errors ? -1 : 0);
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}
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/* ----- copy ----- */
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int nextline() {
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	register t;
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	lineno++;
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	argnum = 1;
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	switch (t = table1()) {
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	case EOF:
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		return(0);
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	case sp_fmnem:
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		instr();
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		break;
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	case sp_fpseu:
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		pseudo();
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		break;
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	case sp_ilb1:
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	case sp_ilb2:
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		argnum = 0;
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		putarg(sp_cst2);
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		break;
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	case sp_dlb1:
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	case sp_dlb2:
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	case sp_dnam:
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		argnum = 0;
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		putarg(t);
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		break;
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	default:
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		error("unknown opcode %d",t);
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	}
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	putchar('\n');
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	return(1);
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}
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instr() {
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	register i,j,t;
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	register long l;
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	i = opcode - sp_fmnem;
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	printf(" %s",em_mnem[i]);
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	j = em_flag[i] & EM_PAR;
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	if (j == PAR_NO)
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		return;
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	t = em_ptyp[j];
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	t = getarg(t);
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	/*
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	 * range checking
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	 */
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	switch (j) {
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	case PAR_N:
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		check(argval >= 0);
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		break;
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	case PAR_G:
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		if (t != sp_cst2 && t != sp_cst4)
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			break;
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		check(argval >= 0);
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		/* fall through */
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	case PAR_L:
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		l = argval >= 0 ? argval : -argval;
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		check((l & ~wordmask[psize]) == 0);
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		break;
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	case PAR_W:
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		if (t == sp_cend)
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			break;
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		check((argval & ~wordmask[wsize]) == 0);
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		/* fall through */
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	case PAR_S:
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		check(argval != 0);
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		/* fall through */
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	case PAR_Z:
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		check((argval & ~sizemask[wsize]) == 0);
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		break;
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	case PAR_O:
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		check(argval != 0);
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		check((argval & ~sizemask[wsize])==0 || (wsize % argval)==0);
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		break;
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	case PAR_B:
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		t = sp_ilb2;
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		break;
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	case PAR_R:
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		check(argval >= 0 && argval <= 2);
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		break;
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	}
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	putarg(t);
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}
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pseudo() {
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	register i,t;
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	i = opcode;
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	printf(" %s",em_pseu[i - sp_fpseu]);
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	switch (i) {
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	case ps_bss:
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	case ps_hol:
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		putarg(getarg(cst_ptyp));
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		putarg(getarg(val_ptyp));
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		putarg(getarg(ptyp(sp_cst2)));
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		check(argval==0 || argval==1);
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		break;
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	case ps_rom:
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	case ps_con:
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		putarg(getarg(val_ptyp));
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		while ((t = getarg(any_ptyp)) != sp_cend)
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			putarg(t);
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		break;
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	case ps_mes:
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		putarg(getarg(ptyp(sp_cst2)));
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		if (argval == ms_emx) {
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			putarg(getarg(ptyp(sp_cst2)));
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			check(argval > 0 && argval <= 4);
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			wsize = (int) argval;
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			putarg(getarg(ptyp(sp_cst2)));
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			check(argval > 0 && argval <= 4);
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			psize = (int) argval;
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		}
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		while ((t = getarg(any_ptyp)) != sp_cend)
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			putarg(t);
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		break;
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	case ps_exa:
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	case ps_ina:
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		putarg(getarg(sym_ptyp));
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		break;
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	case ps_exp:
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	case ps_inp:
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		putarg(getarg(ptyp(sp_pnam)));
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		break;
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	case ps_exc:
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		putarg(getarg(ptyp(sp_cst2)));
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		putarg(getarg(ptyp(sp_cst2)));
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		break;
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	case ps_pro:
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		putarg(getarg(ptyp(sp_pnam)));
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		putarg(getarg(cst_ptyp|ptyp(sp_cend)));
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		break;
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	case ps_end:
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		putarg(getarg(cst_ptyp|ptyp(sp_cend)));
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		break;
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	default:
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		error("bad pseudo %d",i);
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	}
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}
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/* ----- input ----- */
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int getarg(typset) {
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	register t,argtyp;
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	argtyp = t = table2();
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	if (t == EOF)
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		fatal("unexpected EOF");
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	t -= sp_fspec;
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	assert(t >= 0 && t < 16);
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	t = 1 << t;
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	if ((typset & t) == 0)
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		error("bad argument type %d",argtyp);
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	return(argtyp);
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}
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int table1() {
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	register i;
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	i = get8();
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	if (i < sp_fmnem+sp_nmnem && i >= sp_fmnem) {
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		opcode = i;
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		return(sp_fmnem);
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	}
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	if (i < sp_fpseu+sp_npseu && i >= sp_fpseu) {
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		opcode = i;
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		return(sp_fpseu);
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	}
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	if (i < sp_filb0+sp_nilb0 && i >= sp_filb0) {
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		argval = i - sp_filb0;
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		return(sp_ilb2);
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	}
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	return(table3(i));
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}
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int table2() {
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	register i;
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	i = get8();
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	if (i < sp_fcst0+sp_ncst0 && i >= sp_fcst0) {
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		argval = i - sp_zcst0;
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		return(sp_cst2);
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	}
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	return(table3(i));
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}
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int table3(i) {
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	long consiz;
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	switch(i) {
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	case sp_ilb1:
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		argval = get8();
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		break;
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	case sp_dlb1:
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		dlbval = get8();
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		break;
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	case sp_dlb2:
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		dlbval = get16();
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		if ( dlbval<0 ) {
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			error("illegal data label .%d",dlbval);
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			dlbval=0 ;
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		}
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		break;
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	case sp_cst2:
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		argval = get16();
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		break;
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	case sp_ilb2:
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		argval = get16();
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		if ( argval<0 ) {
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			error("illegal instruction label %D",argval);
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			argval=0 ;
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		}
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		break;
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	case sp_cst4:
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		argval = get32();
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		break;
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	case sp_dnam:
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	case sp_pnam:
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		getstring(1);
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		break;
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	case sp_scon:
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		getstring(0);
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		break;
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	case sp_doff:
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		offtyp = getarg(sym_ptyp);
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		getarg(cst_ptyp);
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		break;
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	case sp_icon:
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	case sp_ucon:
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	case sp_fcon:
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		getarg(cst_ptyp);
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		consiz = (long) argval;
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		getstring(0);
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		argval = consiz;
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		break;
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	}
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	return(i);
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}
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int get16() {
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	register int l_byte, h_byte;
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	l_byte = get8();
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	h_byte = get8();
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	if ( h_byte>=128 ) h_byte -= 256 ;
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	return l_byte | (h_byte*256) ;
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}
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long get32() {
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	register long l;
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	register int h_byte;
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	l = get8(); l |= (unsigned)get8()*256 ; l |= get8()*256L*256L ;
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	h_byte = get8() ;
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	if ( h_byte>=128 ) h_byte -= 256 ;
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	return l | (h_byte*256L*256*256L) ;
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}
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getstring(ident) {
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	register char *p;
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	register n;
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	getarg(cst_ptyp);
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	if (argval < 0 || argval > MAXSTR)
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		fatal("string/identifier too long");
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	strsiz = n = argval;
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	p = string;
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	while (--n >= 0)
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		*p++ = get8();
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	if (ident) {
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		if (!isascii(string[0]) || !isalpha(string[0])) {
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			identerror();
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			return;
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		}
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		for (n=strsiz,p=string+1;--n>0;p++)
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			if (!isascii(*p) || !isalnum(*p)) {
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				identerror();
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				return;
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			}
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	}
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}
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 | 
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/* ----- output ----- */
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putarg(t) {
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	if (argnum != 0)
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		putchar(argnum == 1 ? ' ' : ',');
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	argnum++;
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	puttyp(t);
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}
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puttyp(t) {
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	switch (t) {
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	case sp_ilb1:
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	case sp_ilb2:
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		printf("*%d",(int) argval);
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		break;
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	case sp_dlb1:
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	case sp_dlb2:
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		printf(".%d",dlbval);
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		break;
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	case sp_dnam:
 | 
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		putstr(0,0);
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		break;
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	case sp_cst2:
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	case sp_cst4:
 | 
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		printf("%D",argval);
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		break;
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	case sp_doff:
 | 
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		puttyp(offtyp);
 | 
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		if (argval >= 0) putchar('+');
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		printf("%D",argval);
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		break;
 | 
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	case sp_pnam:
 | 
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		putstr('$',0);
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		break;
 | 
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	case sp_scon:
 | 
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		putstr('\'','\'');
 | 
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		break;
 | 
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	case sp_icon:
 | 
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		putstr(0,'I');
 | 
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		printf("%D",argval);
 | 
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		break;
 | 
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	case sp_ucon:
 | 
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		putstr(0,'U');
 | 
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		printf("%D",argval);
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		break;
 | 
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	case sp_fcon:
 | 
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		putstr(0,'F');
 | 
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		printf("%D",argval);
 | 
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		break;
 | 
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	case sp_cend:
 | 
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		putchar('?');
 | 
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		break;
 | 
						|
	}
 | 
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}
 | 
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 | 
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putstr(c,c2) register c; {
 | 
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	register char *p;
 | 
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 | 
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	if (c)
 | 
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		putchar(c);
 | 
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	p = string;
 | 
						|
	while (--strsiz >= 0) {
 | 
						|
		c = *p++ & 0377;
 | 
						|
		if (c >= 040 && c < 0177) {
 | 
						|
			if (c == '\'' || c == '\\')
 | 
						|
				putchar('\\');
 | 
						|
			putchar(c);
 | 
						|
		} else
 | 
						|
			printf("\\%03o",c);
 | 
						|
	}
 | 
						|
	if (c2)
 | 
						|
		putchar(c2);
 | 
						|
}
 | 
						|
 | 
						|
/* ----- error handling ----- */
 | 
						|
 | 
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fail_check() {
 | 
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	error("argument range error");
 | 
						|
}
 | 
						|
 | 
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identerror() {
 | 
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	error("'%s' is not a correct identifier",string);
 | 
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}
 | 
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 | 
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/* VARARGS */
 | 
						|
error(s,a1,a2,a3,a4) char *s; {
 | 
						|
	fprintf(stderr,
 | 
						|
		"%s: line %d: ",
 | 
						|
		filename ? filename : progname,
 | 
						|
		lineno);
 | 
						|
	fprintf(stderr,s,a1,a2,a3,a4);
 | 
						|
	fprintf(stderr,"\n");
 | 
						|
	errors++;
 | 
						|
}
 | 
						|
 | 
						|
/* VARARGS */
 | 
						|
fatal(s,a1,a2,a3,a4) char *s; {
 | 
						|
	error(s,a1,a2,a3,a4);
 | 
						|
	exit(-1);
 | 
						|
}
 |