xref: /csrg-svn/old/as.vax/asparse.c (revision 16570)

/*
 *	Copyright (c) 1982 Regents of the University of California
 */
#ifndef lint
static char sccsid[] = "@(#)asparse.c 4.19 06/06/84";
#endif not lint

#include <stdio.h>
#include "as.h"
#include "asscan.h"
#include "assyms.h"
#include "asexpr.h"

int	lgensym[10];
char	genref[10];

long	bitfield;
int	bitoff;
int	curlen;			/* current length of literals */

/*
 *	The following three variables are communication between various
 *	modules to special case a number of things.  They are properly
 *	categorized as hacks.
 */
extern	struct	symtab *lastnam;/*last name seen by the lexical analyzer*/
int	exprisname;		/*last factor in an expression was a name*/
int	droppedLP;		/*one is analyzing an expression beginning with*/
				/*a left parenthesis, which has already been*/
				/*shifted. (Used to parse (<expr>)(rn)*/

char	yytext[NCPName+2];	/*the lexical image*/
int	yylval;			/*the lexical value; sloppy typing*/
struct	Opcode		yyopcode;	/* lexical value for an opcode */
Bignum	yybignum;		/* lexical value for a big number */
/*
 *	Expression and argument managers
 */
struct	exp	*xp;		/*next free expression slot, used by expr.c*/
struct	exp	explist[NEXP];	/*max of 20 expressions in one opcode*/
struct	arg	arglist[NARG];	/*building up operands in instructions*/
/*
 *	Sets to accelerate token discrimination
 */
char	tokensets[(LASTTOKEN) - (FIRSTTOKEN) + 1];

static	char	UDotsname[64];	/*name of the assembly source*/

yyparse()
{
	reg	struct	exp	*locxp;
		/*
		 *	loc1xp and ptrloc1xp are used in the
		 * 	expression lookahead
		 */
		struct	exp	*loc1xp;	/*must be non register*/
		struct	exp	**ptrloc1xp = & loc1xp;
		struct	exp	*pval;		/*hacking expr:expr*/

	reg	struct	symtab	*np;
	reg	int		argcnt;

	reg	inttoktype	val;		/*what yylex gives*/
	reg	inttoktype	auxval;		/*saves val*/

	reg	struct 	arg	*ap;		/*first free argument*/

	reg	struct	symtab	*p;
	reg	struct	symtab	*stpt;

		struct	strdesc *stringp;	/*handles string lists*/

		int	regno;		/*handles arguments*/
		int	*ptrregno = &regno;
		int	sawmul;		/*saw * */
		int	sawindex;	/*saw [rn]*/
		int	sawsize;
		int	seg_type; 	/*the kind of segment: data or text*/
		int	seg_number;	/*the segment number*/
		int	space_value;	/*how much .space needs*/
		int	fill_rep;	/*how many reps for .fill */
		int	fill_size;	/*how many bytes for .fill */

		int	field_width;	/*how wide a field is to be*/
		int	field_value;	/*the value to stuff in a field*/
		char	*stabname;	/*name of stab dealing with*/
		ptrall	stabstart;	/*where the stab starts in the buffer*/
		int	reloc_how;	/* how to relocate expressions */
		int	toconv;		/* how to convert bignums */
		int	incasetable;	/* set if in a case table */

	incasetable = 0;
	xp = explist;
	ap = arglist;

	val = yylex();

    while (val != PARSEEOF){	/* primary loop */

	while (INTOKSET(val, LINSTBEGIN)){
		if (val == INT) {
			int i = ((struct exp *)yylval)->e_xvalue;
			shift;
			if (val != COLON){
				yyerror("Local label %d is not followed by a ':' for a label definition",
					i);
				goto  errorfix;
			}
			if (i < 0 || i > 9) {
				yyerror("Local labels are 0-9");
				goto errorfix;
			}
			(void)sprintf(yytext, "L%d\001%d", i, lgensym[i]);
			lgensym[i]++;
			genref[i] = 0;
			yylval = (int)*lookup(passno == 1);
			val = NAME;
			np = (struct symtab *)yylval;
			goto restlab;
		}
		if (val == NL){
			lineno++;
			shift;
		} else
		if (val == SEMI)
			shift;
		else {	/*its a name, so we have a label or def */
			if (val != NAME){
				ERROR("Name expected for a label");
			}
			np = (struct symtab *)yylval;
			shiftover(NAME);
			if (val != COLON) {
				yyerror("\"%s\" is not followed by a ':' for a label definition",
					FETCHNAME(np));
				goto  errorfix;
			}
restlab:
			shift;
			flushfield(NBPW/4);
			if ((np->s_type&XTYPE)!=XUNDEF) {
				if (  (np->s_type&XTYPE) != dotp->e_xtype
				   || np->s_value != dotp->e_xvalue
				   || (   passno == 1
				       && np->s_index != dotp->e_xloc) ) {
					if (passno == 1)
						yyerror("%s redefined",
							FETCHNAME(np));
					else
						yyerror("%s redefined: PHASE ERROR, 1st: %d, 2nd: %d",
							FETCHNAME(np),
							np->s_value,
							dotp->e_xvalue);
				}
			}
			np->s_type &= ~(XTYPE|XFORW);
			np->s_type |= dotp->e_xtype;
			np->s_value = dotp->e_xvalue;
			if (passno == 1){
				np->s_index = dotp-usedot;
				if (FETCHNAME(np)[0] == 'L'){
					nlabels++;
				}
				np->s_tag = LABELID;
			}
		}	/*end of this being a label*/
	}	/*end of consuming all labels, NLs and SEMIS */

	xp = explist;
	ap = arglist;

	/*
	 *	process the INSTRUCTION body
	 */
	switch(val){

    default:
	ERROR("Unrecognized instruction or directive");

   case IABORT:
	shift;
	sawabort();
	/*NOTREACHED*/
	break;

   case PARSEEOF:
	tokptr -= sizeof(bytetoktype);
	*tokptr++ = VOID;
	tokptr[1] = VOID;
	tokptr[2] = PARSEEOF;
	break;

   case IFILE:
	shift;
	stringp = (struct strdesc *)yylval;
	shiftover(STRING);
	dotsname = &UDotsname[0];
	movestr(dotsname, stringp->sd_string,
		min(stringp->sd_strlen, sizeof(UDotsname)));
	break;

   case ILINENO:
	shift;		/*over the ILINENO*/
	expr(locxp, val);
	lineno = locxp->e_xvalue;
	break;

   case ISET: 	/* .set  <name> , <expr> */
	shift;
	np = (struct symtab *)yylval;
	shiftover(NAME);
	shiftover(CM);
	expr(locxp, val);
	np->s_type &= (XXTRN|XFORW);
	np->s_type |= locxp->e_xtype&(XTYPE|XFORW);
	np->s_value = locxp->e_xvalue;
	if (passno==1)
		np->s_index = locxp->e_xloc;
	if ((locxp->e_xtype&XTYPE) == XUNDEF)
		yyerror("Illegal set?");
	break;

   case ILSYM: 	/*.lsym name , expr */
	shift;
	np = (struct symtab *)yylval;
	shiftover(NAME);
	shiftover(CM);
	expr(locxp, val);
	/*
	 *	Build the unique occurance of the
	 *	symbol.
	 *	The character scanner will have
	 *	already entered it into the symbol
	 *	table, but we should remove it
	 */
	if (passno == 1){
		stpt = (struct symtab *)symalloc();
		stpt->s_name = np->s_name;
		np->s_tag = OBSOLETE;	/*invalidate original */
		nforgotten++;
		np = stpt;
		if ( (locxp->e_xtype & XTYPE) != XABS)
			yyerror("Illegal second argument to lsym");
		np->s_value = locxp->e_xvalue;
		np->s_type = XABS;
		np->s_tag = ILSYM;
	}
	break;

   case IGLOBAL: 	/*.globl <name> */
	shift;
	np = (struct symtab *)yylval;
	shiftover(NAME);
	np->s_type |= XXTRN;
	break;

   case IDATA: 	/*.data [ <expr> ] */
   case ITEXT: 	/*.text [ <expr> ] */
	seg_type = -val;
	shift;
	if (INTOKSET(val, EBEGOPS+YUKKYEXPRBEG+SAFEEXPRBEG)){
		expr(locxp, val);
		seg_type = -seg_type;   /*now, it is positive*/
	}

	if (seg_type < 0) {	/*there wasn't an associated expr*/
		seg_number = 0;
		seg_type = -seg_type;
	} else {
		if (   ((locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		    || (seg_number = locxp->e_xvalue) >= NLOC) {
			yyerror("illegal location counter");
			seg_number = 0;
		}
	}
	if (seg_type == IDATA)
		seg_number += NLOC;
	flushfield(NBPW/4);
	dotp = &usedot[seg_number];
	if (passno==2) {	/* go salt away in pass 2*/
		txtfil = usefile[seg_number];
		relfil = rusefile[seg_number];
	}
	break;

	/*
	 *	Storage filler directives:
	 *
	 *	.byte	[<exprlist>]
	 *
	 *	exprlist:  empty | exprlist outexpr
	 *	outexpr:   <expr> | <expr> : <expr>
	 */
   case IBYTE:	curlen = NBPW/4; goto elist;
   case IWORD:	curlen = NBPW/2; goto elist;
   case IINT:	curlen = NBPW;   goto elist;
   case ILONG:	curlen = NBPW;   goto elist;

   elist:
	seg_type = val;
	shift;

	/*
	 *	Expression List processing
	 */
	if (INTOKSET(val, EBEGOPS+YUKKYEXPRBEG+SAFEEXPRBEG)){
	    do{
		/*
		 *	expression list consists of a list of :
		 *	<expr>
		 *	<expr> : <expr>
		 *		(pack expr2 into expr1 bits
		 */
		expr(locxp, val);
		/*
		 *	now, pointing at the next token
		 */
		if (val == COLON){
			shiftover(COLON);
			expr(pval, val);
			if ((locxp->e_xtype & XTYPE) != XABS) /* tekmdp */
				yyerror("Width not absolute");
			field_width = locxp->e_xvalue;
			locxp = pval;
			if (bitoff + field_width > curlen)
				flushfield(curlen);
			if (field_width > curlen)
				yyerror("Expression crosses field boundary");
		} else {
			field_width = curlen;
			flushfield(curlen);
		}

		if ((locxp->e_xtype & XTYPE) != XABS) {
			if (bitoff)
				yyerror("Illegal relocation in field");
			switch(curlen){
				case NBPW/4:	reloc_how = TYPB; break;
				case NBPW/2:	reloc_how = TYPW; break;
				case NBPW:	reloc_how = TYPL; break;
			}
			if (passno == 1){
				dotp->e_xvalue += ty_nbyte[reloc_how];
			} else {
				outrel(locxp, reloc_how);
			}
		} else {
			/*
			 *
			 *	See if we are doing a case instruction.
			 *	If so, then see if the branch distance,
			 *	stored as a word,
			 *	is going to loose sig bits.
			 */
			if (passno == 2 && incasetable){
				if (  (locxp->e_xvalue < -32768)
				    ||(locxp->e_xvalue > 32767)){
					yyerror("Case will branch too far");
				}
			}
			field_value = locxp->e_xvalue & ( (1L << field_width)-1);
			bitfield |= field_value << bitoff;
			bitoff += field_width;
		}
		xp = explist;
		if (auxval = (val == CM))
			shift;
	    } while (auxval);
	}	/* there existed an expression at all */

	flushfield(curlen);
	if ( ( curlen == NBPW/4) && bitoff)
		dotp->e_xvalue ++;
	break;
	/*end of case IBYTE, IWORD, ILONG, IINT*/

   case ISPACE: 	/* .space <expr> */
	shift;
	expr(locxp, val);
	if ((locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		yyerror("Space size not absolute");
	space_value = locxp->e_xvalue;
  ospace:
	flushfield(NBPW/4);
	{
		static char spacebuf[128];
		while (space_value > sizeof(spacebuf)){
			outs(spacebuf, sizeof(spacebuf));
			space_value -= sizeof(spacebuf);
		}
		outs(spacebuf, space_value);
	}
	break;

	/*
	 *	.fill rep, size, value
	 *	repeat rep times: fill size bytes with (truncated) value
	 *	size must be between 1 and 8
	 */
   case	IFILL:
	shift;
	expr(locxp, val);
	if ( (locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		yyerror("Fill repetition count not absolute");
	fill_rep = locxp->e_xvalue;
	shiftover(CM);
	expr(locxp, val);
	if ( (locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		yyerror("Fill size not absolute");
	fill_size = locxp->e_xvalue;
	if (fill_size <= 0 || fill_size > 8)
		yyerror("Fill count not in in 1..8");
	shiftover(CM);
	expr(locxp, val);
	if (passno == 2 && (locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		yyerror("Fill value not absolute");
	flushfield(NBPW/4);
	dotp->e_xvalue += fill_rep * fill_size;
	if (passno == 2) {
		while(fill_rep-- > 0)
			bwrite((char *)&locxp->e_xvalue, fill_size, txtfil);
	}
	break;

   case IASCII:		/* .ascii [ <stringlist> ] */
   case IASCIZ: 	/* .asciz [ <stringlist> ] */
	auxval = val;
	shift;
	/*
	 *	Code to consume a string list
	 *
	 *	stringlist: empty | STRING | stringlist STRING
	 */
	while (val == STRING){
		int	mystrlen;
		flushfield(NBPW/4);
		if (bitoff)
			dotp->e_xvalue++;
		stringp = (struct strdesc *)yylval;
		/*
		 *	utilize the string scanner cheat;
		 *	the scanner appended a null byte on the string,
		 *	but didn't charge it to sd_strlen
		 */
		mystrlen = stringp->sd_strlen;
		mystrlen += (auxval == IASCIZ) ? 1 : 0;
		if (passno == 2){
			if (stringp->sd_place & STR_CORE){
				outs(stringp->sd_string, mystrlen);
			} else {
				int	i, nread;
				fseek(strfile, stringp->sd_stroff, 0);
				for (i = 0; i < mystrlen;/*VOID*/){
					nread = fread(yytext, 1,
						min(mystrlen - i,
						  sizeof(yytext)), strfile);
					outs(yytext, nread);
					i += nread;
				}
			}
		} else {
			dotp->e_xvalue += mystrlen;
		}
		shift;		/*over the STRING*/
		if (val == CM)	/*could be a split string*/
			shift;
	}
	break;

   case IORG: 	/* .org <expr> */
	shift;
	expr(locxp, val);

	if ((locxp->e_xtype & XTYPE) == XABS)	/* tekmdp */
		orgwarn++;
	else if ((locxp->e_xtype & ~XXTRN) != dotp->e_xtype)
		yyerror("Illegal expression to set origin");
	space_value = locxp->e_xvalue - dotp->e_xvalue;
	if (space_value < 0)
		yyerror("Backwards 'org'");
	goto ospace;
	break;

/*
 *
 *	Process stabs.  Stabs are created only by the f77
 *	and the C compiler with the -g flag set.
 *	We only look at the stab ONCE, during pass 1, and
 *	virtually remove the stab from the intermediate file
 *	so it isn't seen during pass2.  This makes for some
 *	hairy processing to handle labels occuring in
 *	stab entries, but since most expressions in the
 *	stab are integral we save lots of time in the second
 *	pass by not looking at the stabs.
 *	A stab that is tagged floating will be bumped during
 *	the jxxx resolution phase.  A stab tagged fixed will
 *	not be be bumped.
 *
 *	.stab:	Old fashioned stabs
 *	.stabn: For stabs without names
 *	.stabs:	For stabs with string names
 *	.stabd: For stabs for line numbers or bracketing,
 *		without a string name, without
 *		a final expression.  The value of the
 *		final expression is taken to be  the current
 *		location counter, and is patched by the 2nd pass
 *
 *	.stab{<expr>,}*NCPName,<expr>, <expr>, <expr>, <expr>
 *	.stabn		 <expr>, <expr>, <expr>, <expr>
 *	.stabs   STRING, <expr>, <expr>, <expr>, <expr>
 *	.stabd		 <expr>, <expr>, <expr> # .
 */
   case ISTAB:
	yyerror(".stab directive no longer supported");
	goto errorfix;

  tailstab:
	expr(locxp, val);
	if (! (locxp->e_xvalue & STABTYPS)){
		yyerror("Invalid type in %s", stabname);
		goto errorfix;
	}
	stpt->s_ptype = locxp->e_xvalue;
	shiftover(CM);
	expr(locxp, val);
	stpt->s_other = locxp->e_xvalue;
	shiftover(CM);
	expr(locxp, val);
	stpt->s_desc = locxp->e_xvalue;
	shiftover(CM);
	exprisname = 0;
	expr(locxp, val);
	p = locxp->e_xname;
	if (p == NULL) {	/*absolute expr to begin with*/
		stpt->s_value = locxp->e_xvalue;
		stpt->s_index = dotp - usedot;
		if (exprisname){
			switch(stpt->s_ptype){
				case N_GSYM:
				case N_FNAME:
				case N_RSYM:
				case N_SSYM:
				case N_LSYM:
				case N_PSYM:
				case N_BCOMM:
				case N_ECOMM:
				case N_LENG:
					stpt->s_tag = STABFIXED;
					break;
				default:
					stpt->s_tag = STABFLOATING;
					break;
			}
		} else
			stpt->s_tag = STABFIXED;
	}
	else {		/*really have a name*/
		stpt->s_dest = locxp->e_xname;
		stpt->s_index = p->s_index;
		stpt->s_type = p->s_type | STABFLAG;
		/*
		 *	We will assign a more accruate
		 *	guess of locxp's location when
		 *	we sort the symbol table
		 *	The final value of value is
		 *	given by stabfix()
		 */
/*
 * For exprs of the form (name + value) one needs to remember locxp->e_xvalue
 * for use in stabfix. The right place to keep this is in stpt->s_value
 * however this gets corrupted at an unknown point.
 * As a bandaid hack the value is preserved in s_desc and s_other (a
 * short and a char). This destroys these two values and will
 * be fixed. May 19 ,1983 Alastair Fyfe
 */
		if(locxp->e_xvalue) {
			stpt->s_other = (locxp->e_xvalue >> 16);
			stpt->s_desc =  (locxp->e_xvalue  & 0x0000ffff);
			stpt->s_tag = STABFLOATING;
		}
	}
	/*
	 *	tokptr now points at one token beyond
	 *	the current token stored in val and yylval,
	 *	which are the next tokens after the end of
	 *	this .stab directive.  This next token must
	 *	be either a SEMI or NL, so is of width just
	 *	one.  Therefore, to point to the next token
	 *	after the end of this stab, just back up one..
	 */
	buildskip(stabstart, (bytetoktype *)tokptr - sizeof(bytetoktype));
	break;	/*end of the .stab*/

   case ISTABDOT:
	stabname = ".stabd";
	stpt = (struct symtab *)yylval;
	/*
	 *	We clobber everything after the
	 *	.stabd and its pointer... we MUST
	 *	be able to get back to this .stabd
	 *	so that we can resolve its final value
	 */
	stabstart = tokptr;
	shift;		/*over the ISTABDOT*/
	if (passno == 1){
		expr(locxp, val);
		if (! (locxp->e_xvalue & STABTYPS)){
			yyerror("Invalid type in .stabd");
			goto errorfix;
		}
		stpt->s_ptype = locxp->e_xvalue;
		shiftover(CM);
		expr(locxp, val);
		stpt->s_other = locxp->e_xvalue;
		shiftover(CM);
		expr(locxp, val);
		stpt->s_desc = locxp->e_xvalue;
		/*
		 *
		 *	Now, clobber everything but the
		 *	.stabd pseudo and the pointer
		 *	to its symbol table entry
		 *	tokptr points to the next token,
		 *	build the skip up to this
		 */
		buildskip(stabstart, (bytetoktype *)tokptr - sizeof(bytetoktype));
	}
	/*
	 *	pass 1:	Assign a good guess for its position
	 *		(ensures they are sorted into right place)/
	 *	pass 2:	Fix the actual value
	 */
	stpt->s_value = dotp->e_xvalue;
	stpt->s_index = dotp - usedot;
	stpt->s_tag = STABFLOATING;	/*although it has no effect in pass 2*/
	break;

   case ISTABNONE:	stabname = ".stabn"; goto shortstab;

   case ISTABSTR: 	stabname = ".stabs";
   shortstab:
	auxval = val;
	if (passno == 2) goto errorfix;
	stpt = (struct symtab *)yylval;
	stabstart = tokptr;
	(bytetoktype *)stabstart -= sizeof(struct symtab *);
	(bytetoktype *)stabstart -= sizeof(bytetoktype);
	shift;
	if (auxval == ISTABSTR){
		stringp = (struct strdesc *)yylval;
		shiftover(STRING);
		stpt->s_name = (char *)stringp;
		/*
		 *	We want the trailing null included in this string.
		 *	We utilize the cheat the string scanner used,
		 *	and merely increment the string length
		 */
		stringp->sd_strlen += 1;
		shiftover(CM);
	} else {
		stpt->s_name = (char *)savestr("\0", 0, STR_BOTH);
	}
	goto tailstab;
	break;

   case ICOMM:		/* .comm  <name> , <expr> */
   case ILCOMM: 	/* .lcomm <name> , <expr> */
	auxval = val;
	shift;
	np = (struct symtab *)yylval;
	shiftover(NAME);
	shiftover(CM);
	expr(locxp, val);

	if ( (locxp->e_xtype & XTYPE) != XABS)	/* tekmdp */
		yyerror("comm size not absolute");
	if (passno == 1 && (np->s_type&XTYPE) != XUNDEF)
		yyerror("Redefinition of %s", FETCHNAME(np));
	if (passno==1) {
		np->s_value = locxp->e_xvalue;
		if (auxval == ICOMM)
			np->s_type |= XXTRN;
		else {
			np->s_type &= ~XTYPE;
			np->s_type |= XBSS;
		}
	}
	break;

   case IALIGN: 		/* .align <expr> */
	stpt = (struct symtab *)yylval;
	shift;
	expr(locxp, val);
	jalign(locxp, stpt);
	break;

   case INST0: 		/* instructions w/o arguments*/
	incasetable = 0;
	insout(yyopcode, (struct arg *)0, 0);
	shift;
	break;

   case INSTn:		/* instructions with arguments*/
   case IJXXX: 		/* UNIX style jump instructions */
	auxval = val;
	/*
	 *	Code to process an argument list
	 */
	ap = arglist;
	xp = explist;

	shift;		/* bring in the first token for the arg list*/

	for (argcnt = 1; argcnt <= 6; argcnt++, ap++){
		/*
		 *	code to process an argument proper
		 */
	    sawindex  = sawmul = sawsize = 0;
	    {
		switch(val) {

		   default:
		     disp:
			if( !(INTOKSET(val,
				 EBEGOPS
				+YUKKYEXPRBEG
				+SAFEEXPRBEG)) ) {
				ERROR("expression expected");
			}
			expr(ap->a_xp,val);
		     overdisp:
			if ( val == LP || sawsize){
				shiftover(LP);
				findreg(regno);
				shiftover(RP);
				ap->a_atype = ADISP;
				ap->a_areg1 = regno;
			} else {
				ap->a_atype = AEXP;
				ap->a_areg1 = 0;
			}
			goto index;

		   case SIZESPEC:
		     sizespec:
			sawsize = yylval;
			shift;
			goto disp;

		   case REG:
		   case REGOP:
			findreg(regno);
			ap->a_atype = AREG;
			ap->a_areg1 = regno;
			break;

		   case MUL:
			sawmul = 1;
			shift;
			if (val == LP) goto base;
			if (val == LITOP) goto imm;
			if (val == SIZESPEC) goto sizespec;
			if (INTOKSET(val,
				 EBEGOPS
				+YUKKYEXPRBEG
				+SAFEEXPRBEG)) goto disp;
			ERROR("expression, '(' or '$' expected");
			break;

		   case LP:
		     base:
			shift;	/*consume the LP*/
			/*
			 *	hack the ambiguity of
			 *	movl (expr) (rn), ...
			 *	note that (expr) could also
			 *	be (rn) (by special hole in the
			 *	grammar), which we ensure
			 *	means register indirection, instead
			 *	of an expression with value n
			 */
			if (val != REG && val != REGOP){
				droppedLP = 1;
				val = exprparse(val, &(ap->a_xp));
				droppedLP = 0;
				goto overdisp;
			}
			findreg(regno);
			shiftover(RP);
			if (val == PLUS){
				shift;
				ap->a_atype = AINCR;
			} else
				ap->a_atype = ABASE;
			ap->a_areg1 = regno;
			goto index;

		   case LITOP:
		      imm:
			shift;
			expr(locxp, val);
			ap->a_atype = AIMM;
			ap->a_areg1 = 0;
			ap->a_xp = locxp;
			goto index;

		   case MP:
			shift;	/* -(reg) */
			findreg(regno);
			shiftover(RP);
			ap->a_atype = ADECR;
			ap->a_areg1 = regno;
	  index:			/*look for [reg] */
			if (val == LB){
				shift;
				findreg(regno);
				shiftover(RB);
				sawindex = 1;
				ap->a_areg2 = regno;
			}
			break;

		}	/*end of the switch to process an arg*/
	    }	/*end of processing an argument*/

	    if (sawmul){
			/*
			 * Make a concession for *(%r)
			 * meaning *0(%r)
			 */
			if (ap->a_atype == ABASE) {
				ap->a_atype = ADISP;
				xp->e_xtype = XABS;
				xp->e_number = Znumber;
				xp->e_number.num_tag = TYPL;
				xp->e_xloc = 0;
				ap->a_xp = xp++;
			}
			ap->a_atype |= ASTAR;
			sawmul = 0;
	    }
	    if (sawindex){
		ap->a_atype |= AINDX;
		sawindex = 0;
	    }
	    ap->a_dispsize = sawsize == 0 ? d124 : sawsize;
		if (val != CM) break;
		shiftover(CM);
	}	/*processing all the arguments*/

	if (argcnt > 6){
		yyerror("More than 6 arguments");
		goto errorfix;
	}

	/*
	 *	See if this is a case instruction,
	 *	so we can set up tests on the following
	 *	vector of branch displacements
	 */
	if (yyopcode.Op_eopcode == CORE){
		switch(yyopcode.Op_popcode){
		case 0x8f:	/* caseb */
		case 0xaf:	/* casew */
		case 0xcf:	/* casel */
			incasetable++;
			break;
		default:
			incasetable = 0;
			break;
		}
	}

	insout(yyopcode, arglist,
		auxval == INSTn ? argcnt : - argcnt);
	break;

   case IQUAD:		toconv = TYPQ;	goto bignumlist;
   case IOCTA:		toconv = TYPO;	goto bignumlist;

   case IFFLOAT:	toconv = TYPF;	goto bignumlist;
   case IDFLOAT:	toconv = TYPD;	goto bignumlist;
   case IGFLOAT:	toconv = TYPG;	goto bignumlist;
   case IHFLOAT:	toconv = TYPH;	goto bignumlist;
   bignumlist:
	/*
	 *	eat a list of non 32 bit numbers.
	 *	IQUAD and IOCTA can, possibly, return
	 *	INT's, if the numbers are "small".
	 *
	 *	The value of the numbers is coming back
	 *	as an expression, NOT in yybignum.
	 */
	shift;	/* over the opener */
	if ((val == BIGNUM) || (val == INT)){
		do{
			if ((val != BIGNUM) && (val != INT)){
				ERROR(ty_float[toconv]
				   ? "floating number expected"
				   : "integer number expected" );
			}
			dotp->e_xvalue += ty_nbyte[toconv];
			if (passno == 2){
				bignumwrite(
					((struct exp *)yylval)->e_number,
					toconv);
			}
			xp = explist;
			shift;		/* over this number */
			if (auxval = (val == CM))
				shift;	/* over the comma */
		} while (auxval);	/* as long as there are commas */
	}
	break;
	/* end of the case for initialized big numbers */
    }	/*end of the switch for looking at each reserved word*/

	continue;

   errorfix:
	/*
	 *	got here by either requesting to skip to the
	 *	end of this statement, or by erroring out and
	 *	wanting to apply panic mode recovery
	 */
	while (    (val != NL)
		&& (val != SEMI)
		&& (val != PARSEEOF)
	      ){
		shift;
	}
	if (val == NL)
		lineno++;
	shift;

    }	/*end of the loop to read the entire file, line by line*/

}	/*end of yyparse*/

/*
 *	Process a register declaration of the form
 *	% <expr>
 *
 *	Note:
 *		The scanner has already processed funny registers of the form
 *	%dd[+-]*, where dd is a decimal number in the range 00 to 15 (optional
 *	preceding zero digit).  If there was any space between the % and
 *	the digit, the scanner wouldn't have recognized it, so we
 *	hack it out here.
 */
inttoktype funnyreg(val, regnoback)	/*what the read head will sit on*/
	inttoktype	val;		/*what the read head is sitting on*/
	int	*regnoback;		/*call by return*/
{
	reg	struct	exp *locxp;
		struct	exp *loc1xp;
		struct	exp **ptrloc1xp = & loc1xp;

	expr(locxp, val);	/*and leave the current read head with value*/
	if ( (passno == 2) &&
	    (   (locxp->e_xtype & XTYPE) != XABS
	     || (locxp->e_xvalue < 0)
	     || (locxp->e_xvalue >= 16)
	    )
	  ){
		yyerror("Illegal register");
		return(0);
	}
	*regnoback = locxp->e_xvalue;
	return(val);
}
/*
 *	Shift over error
 */
shiftoerror(token)
	int	token;
{
	char	*tok_to_name();
	yyerror("%s expected", tok_to_name(token));
}

/*VARARGS1*/
yyerror(s, a1, a2,a3,a4,a5)
	char	*s;
{

#define	sink stdout

	if (anyerrs == 0 && anywarnings == 0 && ! silent)
		fprintf(sink, "Assembler:\n");
	anyerrs++;
	if (silent)
		return;
	fprintf(sink, "\"%s\", line %d: ", dotsname, lineno);
	fprintf(sink, s, a1, a2,a3,a4,a5);
	fprintf(sink, "\n");
#undef sink
}

/*VARARGS1*/
yywarning(s, a1, a2,a3,a4,a5)
	char	*s;
{
#define	sink stdout
	if (anyerrs == 0 && anywarnings == 0 && ! silent)
		fprintf(sink, "Assembler:\n");
	anywarnings++;
	if (silent)
		return;
	fprintf(sink, "\"%s\", line %d: WARNING: ", dotsname, lineno);
	fprintf(sink, s, a1, a2,a3,a4,a5);
	fprintf(sink, "\n");
#undef sink
}