[unix-history] / usr / src / old / pcc / mip / allo.c

#ifndef lint
static char *sccsid ="@(#)allo.c	4.8 (Berkeley) %G%";
#endif lint

# include "pass2.h"

NODE resc[3];

int busy[REGSZ];

int maxa, mina, maxb, minb;

# ifndef ALLO0
allo0(){ /* free everything */

	register i;

	maxa = maxb = -1;
	mina = minb = 0;

	REGLOOP(i){
		busy[i] = 0;
		if( rstatus[i] & STAREG ){
			if( maxa<0 ) mina = i;
			maxa = i;
			}
		if( rstatus[i] & STBREG ){
			if( maxb<0 ) minb = i;
			maxb = i;
			}
		}
	}
# endif

# ifndef ALLO
allo( p, q ) NODE *p; struct optab *q; {

	register n, i, j;
	int either;

	n = q->needs;
	either = ( EITHER & n );
	i = 0;

	while( n & NACOUNT ){
		resc[i].in.op = REG;
		resc[i].tn.rval = freereg( p, n&NAMASK );
		resc[i].tn.lval = 0;
#ifdef FLEXNAMES
		resc[i].in.name = "";
#else
		resc[i].in.name[0] = '\0';
#endif
		n -= NAREG;
		++i;
		}

	if (either) { /* all or nothing at all */
		for( j = 0; j < i; j++ )
			if( resc[j].tn.rval < 0 ) { /* nothing */
				i = 0;
				break;
				}
		if( i != 0 ) goto ok; /* all */
		}

	while( n & NBCOUNT ){
		resc[i].in.op = REG;
		resc[i].tn.rval = freereg( p, n&NBMASK );
		resc[i].tn.lval = 0;
#ifdef FLEXNAMES
		resc[i].in.name = "";
#else
		resc[i].in.name[0] = '\0';
#endif
		n -= NBREG;
		++i;
		}
	if (either) { /* all or nothing at all */
		for( j = 0; j < i; j++ )
			if( resc[j].tn.rval < 0 ) { /* nothing */
				i = 0;
				break;
				}
		if( i != 0 ) goto ok; /* all */
		}

	if( n & NTMASK ){
		resc[i].in.op = OREG;
		resc[i].tn.rval = TMPREG;
		if( p->in.op == STCALL || p->in.op == STARG || p->in.op == UNARY STCALL || p->in.op == STASG ){
			resc[i].tn.lval = freetemp( (SZCHAR*p->stn.stsize + (SZINT-1))/SZINT );
			}
		else {
			resc[i].tn.lval = freetemp( (n&NTMASK)/NTEMP );
			}
#ifdef FLEXNAMES
		resc[i].in.name = "";
#else
		resc[i].in.name[0] = '\0';
#endif

		resc[i].tn.lval = BITOOR(resc[i].tn.lval);
		++i;
		}

	/* turn off "temporarily busy" bit */

	ok:
	REGLOOP(j){
		busy[j] &= ~TBUSY;
		}

	for( j=0; j<i; ++j ) if( resc[j].tn.rval < 0 ) return(0);
	return(1);

	}
# endif

extern unsigned int offsz;
freetemp( k ){ /* allocate k integers worth of temp space */
	/* we also make the convention that, if the number of words is more than 1,
	/* it must be aligned for storing doubles... */

# ifndef BACKTEMP
	int t;

	if( k>1 ){
		SETOFF( tmpoff, ALDOUBLE );
		}

	t = tmpoff;
	tmpoff += k*SZINT;
	if( tmpoff > maxoff ) maxoff = tmpoff;
	if( tmpoff >= offsz )
		cerror( "stack overflow" );
	if( tmpoff-baseoff > maxtemp ) maxtemp = tmpoff-baseoff;
	return(t);

# else
	tmpoff += k*SZINT;
	if( k>1 ) {
		SETOFF( tmpoff, ALDOUBLE );
		}
	if( tmpoff > maxoff ) maxoff = tmpoff;
	if( tmpoff >= offsz )
		cerror( "stack overflow" );
	if( tmpoff-baseoff > maxtemp ) maxtemp = tmpoff-baseoff;
	return( -tmpoff );
# endif
	}

freereg( p, n ) NODE *p; {
	/* allocate a register of type n */
	/* p gives the type, if floating */

	register j;

	/* not general; means that only one register (the result) OK for call */
	if( callop(p->in.op) ){
		j = callreg(p);
		if( usable( p, n, j ) ) return( j );
		/* have allocated callreg first */
		}
	j = p->in.rall & ~MUSTDO;
	if( j!=NOPREF && usable(p,n,j) ){ /* needed and not allocated */
		return( j );
		}
	if( n&NAMASK ){
		for( j=mina; j<=maxa; ++j ) if( rstatus[j]&STAREG ){
			if( usable(p,n,j) ){
				return( j );
				}
			}
		}
	else if( n &NBMASK ){
		for( j=minb; j<=maxb; ++j ) if( rstatus[j]&STBREG ){
			if( usable(p,n,j) ){
				return(j);
				}
			}
		}

	return( -1 );
	}

# ifndef USABLE
usable( p, n, r ) NODE *p; {
	/* decide if register r is usable in tree p to satisfy need n */

	/* checks, for the moment */
	if( !istreg(r) ) cerror( "usable asked about nontemp register" );

	if( busy[r] > 1 ) return(0);
	if( isbreg(r) ){
		if( n&NAMASK ) return(0);
		}
	else {
		if( n & NBMASK ) return(0);
		}
	/*
	 * Some special cases that require register pairs...
	 * Have to check for ==, <=, etc. because the result is type int
	 * but need a register pair temp if either side is wide.
	 * For +=, *= etc. where lhs is narrow and rhs is wide, the temp
	 * register must be wide.
	 */
	if( (n&NAMASK) &&
	    (szty(p->in.type) == 2 ||
	     (logop(p->in.op) && (szty(p->in.left->in.type) == 2 ||
	      szty(p->in.right->in.type) == 2)) ||
	     (asgop(p->in.op) && szty(p->in.right->in.type) == 2 &&
	      szty(p->in.left->in.type) == 1))
	){
#ifndef NOEVENODD
		if( r&01 ) return(0);
#endif
		if( !istreg(r+1) ) return( 0 );
		if( busy[r+1] > 1 ) return( 0 );
		if( busy[r] == 0 && busy[r+1] == 0  ||
		    busy[r+1] == 0 && shareit( p, r, n ) ||
		    busy[r] == 0 && shareit( p, r+1, n ) ){
			busy[r] |= TBUSY;
			busy[r+1] |= TBUSY;
			return(1);
			}
		else return(0);
		}
	if( busy[r] == 0 ) {
		busy[r] |= TBUSY;
		return(1);
		}

	/* busy[r] is 1: is there chance for sharing */
	return( shareit( p, r, n ) );

	}
# endif

shareit( p, r, n ) NODE *p; {
	/* can we make register r available by sharing from p
	   given that the need is n */
	if( (n&(NASL|NBSL)) && ushare( p, 'L', r ) ) return(1);
	if( (n&(NASR|NBSR)) && ushare( p, 'R', r ) ) return(1);
	return(0);
	}

ushare( p, f, r ) NODE *p; {
	/* can we find a register r to share on the left or right
		(as f=='L' or 'R', respectively) of p */
	p = getlr( p, f );
	if( p->in.op == UNARY MUL ) p = p->in.left;
	if( p->in.op == OREG ){
		if( R2TEST(p->tn.rval) ){
			return( r==R2UPK1(p->tn.rval) || r==R2UPK2(p->tn.rval) );
			}
		else return( r == p->tn.rval );
		}
	if( p->in.op == REG ){
		return( r == p->tn.rval || ( szty(p->in.type) == 2 && r==p->tn.rval+1 ) );
		}
	return(0);
	}

recl2( p ) register NODE *p; {
	register r = p->tn.rval;
#ifndef OLD
	int op = p->in.op;
	if (op == REG && r >= REGSZ)
		op = OREG;
	if( op == REG ) rfree( r, p->in.type );
	else if( op == OREG ) {
		if( R2TEST( r ) ) {
			if( R2UPK1( r ) != 100 ) rfree( R2UPK1( r ), PTR+INT );
			rfree( R2UPK2( r ), INT );
			}
		else {
			rfree( r, PTR+INT );
			}
		}
#else
	if( p->in.op == REG ) rfree( r, p->in.type );
	else if( p->in.op == OREG ) {
		if( R2TEST( r ) ) {
			if( R2UPK1( r ) != 100 ) rfree( R2UPK1( r ), PTR+INT );
			rfree( R2UPK2( r ), INT );
			}
		else {
			rfree( r, PTR+INT );
			}
		}
#endif
	}

int rdebug = 0;

# ifndef RFREE
rfree( r, t ) TWORD t; {
	/* mark register r free, if it is legal to do so */
	/* t is the type */

# ifndef BUG3
	if( rdebug ){
		printf( "rfree( %s ), size %d\n", rnames[r], szty(t) );
		}
# endif

	if( istreg(r) ){
		if( --busy[r] < 0 ) cerror( "register overfreed");
		if( szty(t) == 2 ){
#ifdef NOEVENODD
			if( istreg(r) ^ istreg(r+1) ) cerror( "illegal free" );
#else
			if( (r&01) || (istreg(r)^istreg(r+1)) ) cerror( "illegal free" );
#endif
			if( --busy[r+1] < 0 ) cerror( "register overfreed" );
			}
		}
	}
# endif

# ifndef RBUSY
rbusy(r,t) TWORD t; {
	/* mark register r busy */
	/* t is the type */

# ifndef BUG3
	if( rdebug ){
		printf( "rbusy( %s ), size %d\n", rnames[r], szty(t) );
		}
# endif

	if( istreg(r) ) ++busy[r];
	if( szty(t) == 2 ){
		if( istreg(r+1) ) ++busy[r+1];
#ifdef NOEVENODD
		if( istreg(r) ^ istreg(r+1) ) cerror( "illegal register pair freed" );
#else
		if( (r&01) || (istreg(r)^istreg(r+1)) ) cerror( "illegal register pair freed" );
#endif
		}
	}
# endif

# ifndef BUG3
rwprint( rw ){ /* print rewriting rule */
	register i, flag;
	static char * rwnames[] = {

		"RLEFT",
		"RRIGHT",
		"RESC1",
		"RESC2",
		"RESC3",
		0,
		};

	if( rw == RNULL ){
		printf( "RNULL" );
		return;
		}

	if( rw == RNOP ){
		printf( "RNOP" );
		return;
		}

	flag = 0;
	for( i=0; rwnames[i]; ++i ){
		if( rw & (1<<i) ){
			if( flag ) printf( "|" );
			++flag;
			printf( rwnames[i] );
			}
		}
	}
# endif

reclaim( p, rw, cookie ) NODE *p; {
	register NODE **qq;
	register NODE *q;
	register i;
	NODE *recres[5];
	struct respref *r;

	/* get back stuff */

# ifndef BUG3
	if( rdebug ){
		printf( "reclaim( %o, ", p );
		rwprint( rw );
		printf( ", " );
		prcook( cookie );
		printf( " )\n" );
		}
# endif

	if( rw == RNOP || ( p->in.op==FREE && rw==RNULL ) ) return;  /* do nothing */

	walkf( p, recl2 );

	if( callop(p->in.op) ){
		/* check that all scratch regs are free */
		callchk(p);  /* ordinarily, this is the same as allchk() */
		}

	if( rw == RNULL || (cookie&FOREFF) ){ /* totally clobber, leaving nothing */
		tfree(p);
		return;
		}

	/* handle condition codes specially */

	if( (cookie & FORCC) && (rw&RESCC)) {
		/* result is CC register */
		tfree(p);
		p->in.op = CCODES;
		p->tn.lval = 0;
		p->tn.rval = 0;
		return;
		}

	/* locate results */

	qq = recres;

	if( rw&RLEFT) *qq++ = getlr( p, 'L' );;
	if( rw&RRIGHT ) *qq++ = getlr( p, 'R' );
	if( rw&RESC1 ) *qq++ = &resc[0];
	if( rw&RESC2 ) *qq++ = &resc[1];
	if( rw&RESC3 ) *qq++ = &resc[2];

	if( qq == recres ){
		cerror( "illegal reclaim");
		}

	*qq = NIL;

	/* now, select the best result, based on the cookie */

	for( r=respref; r->cform; ++r ){
		if( cookie & r->cform ){
			for( qq=recres; (q= *qq) != NIL; ++qq ){
				if( tshape( q, r->mform ) ) goto gotit;
				}
			}
		}

	/* we can't do it; die */
	cerror( "cannot reclaim");

	gotit:

	if( p->in.op == STARG ) p = p->in.left;  /* STARGs are still STARGS */

	q->in.type = p->in.type;  /* to make multi-register allocations work */
		/* maybe there is a better way! */
	q = tcopy(q);

	tfree(p);

	p->in.op = q->in.op;
	p->tn.lval = q->tn.lval;
	p->tn.rval = q->tn.rval;
#ifdef FLEXNAMES
	p->in.name = q->in.name;
#ifdef ONEPASS
	p->in.stalign = q->in.stalign;
#endif
#else
	for( i=0; i<NCHNAM; ++i )
		p->in.name[i] = q->in.name[i];
#endif

	q->in.op = FREE;

	/* if the thing is in a register, adjust the type */

	switch( p->in.op ){

	case REG:
		if( !rtyflg ){
			/* the C language requires intermediate results to change type */
			/* this is inefficient or impossible on some machines */
			/* the "T" command in match supresses this type changing */
			if( p->in.type == CHAR || p->in.type == SHORT ) p->in.type = INT;
			else if( p->in.type == UCHAR || p->in.type == USHORT ) p->in.type = UNSIGNED;
#if !defined(FORT) && !defined(SPRECC)
			else if( p->in.type == FLOAT ) p->in.type = DOUBLE;
#endif
			}
		if( ! (p->in.rall & MUSTDO ) ) return;  /* unless necessary, ignore it */
		i = p->in.rall & ~MUSTDO;
		if( i & NOPREF ) return;
		if( i != p->tn.rval ){
			if( busy[i] || ( szty(p->in.type)==2 && busy[i+1] ) ){
				cerror( "faulty register move" );
				}
			rbusy( i, p->in.type );
			rfree( p->tn.rval, p->in.type );
			rmove( i, p->tn.rval, p->in.type );
			p->tn.rval = i;
			}

	case OREG:
		if( p->in.op == REG || !R2TEST(p->tn.rval) ) {
			if( busy[p->tn.rval]>1 && istreg(p->tn.rval) ) cerror( "potential register overwrite");
			}
		else
			if( (R2UPK1(p->tn.rval) != 100 && busy[R2UPK1(p->tn.rval)]>1 && istreg(R2UPK1(p->tn.rval)) )
				|| (busy[R2UPK2(p->tn.rval)]>1 && istreg(R2UPK2(p->tn.rval)) ) )
			   cerror( "potential register overwrite");
		}

	}

#ifndef ncopy
ncopy( q, p ) NODE *p, *q; {
	/* copy the contents of p into q, without any feeling for
	   the contents */
	/* this code assume that copying rval and lval does the job;
	   in general, it might be necessary to special case the
	   operator types */
	register i;

	q->in.op = p->in.op;
	q->in.rall = p->in.rall;
	q->in.type = p->in.type;
	q->tn.lval = p->tn.lval;
	q->tn.rval = p->tn.rval;
#ifdef FLEXNAMES
	q->in.name = p->in.name;
#ifdef ONEPASS
	q->in.stalign = p->in.stalign;
#endif
#else
	for( i=0; i<NCHNAM; ++i ) q->in.name[i]  = p->in.name[i];
#endif

	}
#endif

NODE *
tcopy( p ) register NODE *p; {
	/* make a fresh copy of p */

	register NODE *q;
	register r;

	ncopy( q=talloc(), p );

	r = p->tn.rval;
	if( p->in.op == REG ) rbusy( r, p->in.type );
	else if( p->in.op == OREG ) {
		if( R2TEST(r) ){
			if( R2UPK1(r) != 100 ) rbusy( R2UPK1(r), PTR+INT );
			rbusy( R2UPK2(r), INT );
			}
		else {
			rbusy( r, PTR+INT );
			}
		}

	switch( optype(q->in.op) ){

	case BITYPE:
		q->in.right = tcopy(p->in.right);
	case UTYPE:
		q->in.left = tcopy(p->in.left);
		}

	return(q);
	}

allchk(){
	/* check to ensure that all register are free */

	register i;

	REGLOOP(i){
		if( istreg(i) && busy[i] ){
			cerror( "register allocation error");
			}
		}

	}
Commit	Line	Data
262eaf56	1	#ifndef lint
57b6b508	2	static char *sccsid ="@(#)allo.c 4.8 (Berkeley) %G%";
262eaf56 RC	3	#endif lint
262eaf56 RC	4
69023ebb	5	# include "pass2.h"
e91423bb RC	6
	7	NODE resc[3];
	8
	9	int busy[REGSZ];
	10
	11	int maxa, mina, maxb, minb;
	12
	13	# ifndef ALLO0
	14	allo0(){ /* free everything */
	15
	16	register i;
	17
	18	maxa = maxb = -1;
	19	mina = minb = 0;
	20
	21	REGLOOP(i){
	22	busy[i] = 0;
	23	if( rstatus[i] & STAREG ){
	24	if( maxa<0 ) mina = i;
	25	maxa = i;
	26	}
	27	if( rstatus[i] & STBREG ){
	28	if( maxb<0 ) minb = i;
	29	maxb = i;
	30	}
	31	}
	32	}
	33	# endif
	34
e91423bb RC	35	# ifndef ALLO
	36	allo( p, q ) NODE p; struct optab q; {
	37
	38	register n, i, j;
	39	int either;
	40
	41	n = q->needs;
	42	either = ( EITHER & n );
	43	i = 0;
	44
	45	while( n & NACOUNT ){
	46	resc[i].in.op = REG;
	47	resc[i].tn.rval = freereg( p, n&NAMASK );
	48	resc[i].tn.lval = 0;
	49	#ifdef FLEXNAMES
	50	resc[i].in.name = "";
	51	#else
	52	resc[i].in.name[0] = '\0';
	53	#endif
	54	n -= NAREG;
	55	++i;
	56	}
	57
	58	if (either) { /* all or nothing at all */
	59	for( j = 0; j < i; j++ )
	60	if( resc[j].tn.rval < 0 ) { /* nothing */
	61	i = 0;
	62	break;
	63	}
	64	if( i != 0 ) goto ok; /* all */
	65	}
	66
	67	while( n & NBCOUNT ){
	68	resc[i].in.op = REG;
	69	resc[i].tn.rval = freereg( p, n&NBMASK );
	70	resc[i].tn.lval = 0;
	71	#ifdef FLEXNAMES
	72	resc[i].in.name = "";
	73	#else
	74	resc[i].in.name[0] = '\0';
	75	#endif
	76	n -= NBREG;
	77	++i;
	78	}
	79	if (either) { /* all or nothing at all */
	80	for( j = 0; j < i; j++ )
	81	if( resc[j].tn.rval < 0 ) { /* nothing */
	82	i = 0;
	83	break;
	84	}
	85	if( i != 0 ) goto ok; /* all */
	86	}
	87
	88	if( n & NTMASK ){
	89	resc[i].in.op = OREG;
	90	resc[i].tn.rval = TMPREG;
	91	if( p->in.op == STCALL \|\| p->in.op == STARG \|\| p->in.op == UNARY STCALL \|\| p->in.op == STASG ){
	92	resc[i].tn.lval = freetemp( (SZCHAR*p->stn.stsize + (SZINT-1))/SZINT );
	93	}
	94	else {
	95	resc[i].tn.lval = freetemp( (n&NTMASK)/NTEMP );
	96	}
	97	#ifdef FLEXNAMES
	98	resc[i].in.name = "";
99	#else
100	resc[i].in.name[0] = '\0';
101	#endif
102
103	resc[i].tn.lval = BITOOR(resc[i].tn.lval);
104	++i;
105	}
106
107	/* turn off "temporarily busy" bit */
108
109	ok:
110	REGLOOP(j){
111	busy[j] &= ~TBUSY;
112	}
113
114	for( j=0; j<i; ++j ) if( resc[j].tn.rval < 0 ) return(0);
115	return(1);
116
117	}
118	# endif
119
120	extern unsigned int offsz;
121	freetemp( k ){ /* allocate k integers worth of temp space */
122	/* we also make the convention that, if the number of words is more than 1,
123	/* it must be aligned for storing doubles... */
124
125	# ifndef BACKTEMP
126	int t;
127
128	if( k>1 ){
129	SETOFF( tmpoff, ALDOUBLE );
130	}
131
132	t = tmpoff;
133	tmpoff += k*SZINT;
134	if( tmpoff > maxoff ) maxoff = tmpoff;
135	if( tmpoff >= offsz )
136	cerror( "stack overflow" );
137	if( tmpoff-baseoff > maxtemp ) maxtemp = tmpoff-baseoff;
138	return(t);
139
140	# else
141	tmpoff += k*SZINT;
142	if( k>1 ) {
143	SETOFF( tmpoff, ALDOUBLE );
144	}
145	if( tmpoff > maxoff ) maxoff = tmpoff;
146	if( tmpoff >= offsz )
147	cerror( "stack overflow" );
148	if( tmpoff-baseoff > maxtemp ) maxtemp = tmpoff-baseoff;
149	return( -tmpoff );
150	# endif
151	}
152
153	freereg( p, n ) NODE *p; {
154	/* allocate a register of type n */
155	/* p gives the type, if floating */
156
157	register j;
158
159	/* not general; means that only one register (the result) OK for call */
160	if( callop(p->in.op) ){
161	j = callreg(p);
162	if( usable( p, n, j ) ) return( j );
163	/* have allocated callreg first */
164	}
165	j = p->in.rall & ~MUSTDO;
166	if( j!=NOPREF && usable(p,n,j) ){ /* needed and not allocated */
167	return( j );
168	}
169	if( n&NAMASK ){
170	for( j=mina; j<=maxa; ++j ) if( rstatus[j]&STAREG ){
171	if( usable(p,n,j) ){
172	return( j );
173	}
174	}
175	}
176	else if( n &NBMASK ){
177	for( j=minb; j<=maxb; ++j ) if( rstatus[j]&STBREG ){
178	if( usable(p,n,j) ){
179	return(j);
180	}
181	}
182	}
183
184	return( -1 );
185	}
186
187	# ifndef USABLE
188	usable( p, n, r ) NODE *p; {
189	/* decide if register r is usable in tree p to satisfy need n */
190
191	/* checks, for the moment */
192	if( !istreg(r) ) cerror( "usable asked about nontemp register" );
193
194	if( busy[r] > 1 ) return(0);
195	if( isbreg(r) ){
196	if( n&NAMASK ) return(0);
197	}
198	else {
199	if( n & NBMASK ) return(0);
200	}
a380d75d	201	/*
57b6b508 DS	202	* Some special cases that require register pairs...
	203	* Have to check for ==, <=, etc. because the result is type int
	204	* but need a register pair temp if either side is wide.
	205	* For +=, *= etc. where lhs is narrow and rhs is wide, the temp
	206	* register must be wide.
a380d75d	207	*/
57b6b508 DS	208	if( (n&NAMASK) &&
	209	(szty(p->in.type) == 2 \|\|
	210	(logop(p->in.op) && (szty(p->in.left->in.type) == 2 \|\|
	211	szty(p->in.right->in.type) == 2)) \|\|
	212	(asgop(p->in.op) && szty(p->in.right->in.type) == 2 &&
	213	szty(p->in.left->in.type) == 1))
	214	){
bd4e35d4	215	#ifndef NOEVENODD
e91423bb	216	if( r&01 ) return(0);
bd4e35d4	217	#endif
e91423bb RC	218	if( !istreg(r+1) ) return( 0 );
	219	if( busy[r+1] > 1 ) return( 0 );
	220	if( busy[r] == 0 && busy[r+1] == 0 \|\|
	221	busy[r+1] == 0 && shareit( p, r, n ) \|\|
	222	busy[r] == 0 && shareit( p, r+1, n ) ){
	223	busy[r] \|= TBUSY;
	224	busy[r+1] \|= TBUSY;
	225	return(1);
	226	}
	227	else return(0);
	228	}
	229	if( busy[r] == 0 ) {
	230	busy[r] \|= TBUSY;
	231	return(1);
	232	}
	233
	234	/* busy[r] is 1: is there chance for sharing */
	235	return( shareit( p, r, n ) );
	236
	237	}
	238	# endif
	239
	240	shareit( p, r, n ) NODE *p; {
	241	/* can we make register r available by sharing from p
	242	given that the need is n */
	243	if( (n&(NASL\|NBSL)) && ushare( p, 'L', r ) ) return(1);
	244	if( (n&(NASR\|NBSR)) && ushare( p, 'R', r ) ) return(1);
	245	return(0);
	246	}
	247
	248	ushare( p, f, r ) NODE *p; {
	249	/* can we find a register r to share on the left or right
	250	(as f=='L' or 'R', respectively) of p */
	251	p = getlr( p, f );
	252	if( p->in.op == UNARY MUL ) p = p->in.left;
	253	if( p->in.op == OREG ){
	254	if( R2TEST(p->tn.rval) ){
	255	return( r==R2UPK1(p->tn.rval) \|\| r==R2UPK2(p->tn.rval) );
	256	}
	257	else return( r == p->tn.rval );
	258	}
	259	if( p->in.op == REG ){
	260	return( r == p->tn.rval \|\| ( szty(p->in.type) == 2 && r==p->tn.rval+1 ) );
	261	}
	262	return(0);
	263	}
	264
	265	recl2( p ) register NODE *p; {
	266	register r = p->tn.rval;
	267	#ifndef OLD
	268	int op = p->in.op;
	269	if (op == REG && r >= REGSZ)
	270	op = OREG;
	271	if( op == REG ) rfree( r, p->in.type );
	272	else if( op == OREG ) {
	273	if( R2TEST( r ) ) {
	274	if( R2UPK1( r ) != 100 ) rfree( R2UPK1( r ), PTR+INT );
	275	rfree( R2UPK2( r ), INT );
	276	}
	277	else {
	278	rfree( r, PTR+INT );
	279	}
	280	}
	281	#else
282	if( p->in.op == REG ) rfree( r, p->in.type );
283	else if( p->in.op == OREG ) {
284	if( R2TEST( r ) ) {
285	if( R2UPK1( r ) != 100 ) rfree( R2UPK1( r ), PTR+INT );
286	rfree( R2UPK2( r ), INT );
287	}
288	else {
289	rfree( r, PTR+INT );
290	}
291	}
292	#endif
293	}
294
295	int rdebug = 0;
296
297	# ifndef RFREE
298	rfree( r, t ) TWORD t; {
299	/* mark register r free, if it is legal to do so */
300	/* t is the type */
301
302	# ifndef BUG3
303	if( rdebug ){
304	printf( "rfree( %s ), size %d\n", rnames[r], szty(t) );
305	}
306	# endif
307
308	if( istreg(r) ){
309	if( --busy[r] < 0 ) cerror( "register overfreed");
310	if( szty(t) == 2 ){
bd4e35d4 RC	311	#ifdef NOEVENODD
	312	if( istreg(r) ^ istreg(r+1) ) cerror( "illegal free" );
	313	#else
e91423bb	314	if( (r&01) \|\| (istreg(r)^istreg(r+1)) ) cerror( "illegal free" );
bd4e35d4	315	#endif
e91423bb RC	316	if( --busy[r+1] < 0 ) cerror( "register overfreed" );
	317	}
	318	}
	319	}
	320	# endif
	321
	322	# ifndef RBUSY
	323	rbusy(r,t) TWORD t; {
	324	/* mark register r busy */
	325	/* t is the type */
	326
	327	# ifndef BUG3
	328	if( rdebug ){
	329	printf( "rbusy( %s ), size %d\n", rnames[r], szty(t) );
	330	}
	331	# endif
	332
	333	if( istreg(r) ) ++busy[r];
	334	if( szty(t) == 2 ){
	335	if( istreg(r+1) ) ++busy[r+1];
bd4e35d4 RC	336	#ifdef NOEVENODD
	337	if( istreg(r) ^ istreg(r+1) ) cerror( "illegal register pair freed" );
	338	#else
e91423bb	339	if( (r&01) \|\| (istreg(r)^istreg(r+1)) ) cerror( "illegal register pair freed" );
bd4e35d4	340	#endif
e91423bb RC	341	}
	342	}
	343	# endif
	344
	345	# ifndef BUG3
	346	rwprint( rw ){ /* print rewriting rule */
	347	register i, flag;
	348	static char * rwnames[] = {
	349
	350	"RLEFT",
	351	"RRIGHT",
	352	"RESC1",
	353	"RESC2",
	354	"RESC3",
	355	0,
	356	};
	357
	358	if( rw == RNULL ){
	359	printf( "RNULL" );
	360	return;
	361	}
	362
	363	if( rw == RNOP ){
	364	printf( "RNOP" );
	365	return;
	366	}
	367
	368	flag = 0;
	369	for( i=0; rwnames[i]; ++i ){
	370	if( rw & (1<<i) ){
	371	if( flag ) printf( "\|" );
	372	++flag;
	373	printf( rwnames[i] );
	374	}
	375	}
	376	}
	377	# endif
	378
	379	reclaim( p, rw, cookie ) NODE *p; {
	380	register NODE **qq;
	381	register NODE *q;
	382	register i;
	383	NODE *recres[5];
	384	struct respref *r;
	385
	386	/* get back stuff */
	387
	388	# ifndef BUG3
	389	if( rdebug ){
	390	printf( "reclaim( %o, ", p );
	391	rwprint( rw );
	392	printf( ", " );
	393	prcook( cookie );
	394	printf( " )\n" );
	395	}
	396	# endif
	397
	398	if( rw == RNOP \|\| ( p->in.op==FREE && rw==RNULL ) ) return; /* do nothing */
	399
	400	walkf( p, recl2 );
	401
	402	if( callop(p->in.op) ){
	403	/* check that all scratch regs are free */
	404	callchk(p); /* ordinarily, this is the same as allchk() */
405	}
406
407	if( rw == RNULL \|\| (cookie&FOREFF) ){ /* totally clobber, leaving nothing */
408	tfree(p);
409	return;
410	}
411
412	/* handle condition codes specially */
413
414	if( (cookie & FORCC) && (rw&RESCC)) {
415	/* result is CC register */
416	tfree(p);
417	p->in.op = CCODES;
418	p->tn.lval = 0;
419	p->tn.rval = 0;
420	return;
421	}
422
423	/* locate results */
424
425	qq = recres;
426
427	if( rw&RLEFT) *qq++ = getlr( p, 'L' );;
428	if( rw&RRIGHT ) *qq++ = getlr( p, 'R' );
429	if( rw&RESC1 ) *qq++ = &resc[0];
430	if( rw&RESC2 ) *qq++ = &resc[1];
431	if( rw&RESC3 ) *qq++ = &resc[2];
432
433	if( qq == recres ){
434	cerror( "illegal reclaim");
435	}
436
437	*qq = NIL;
438
439	/* now, select the best result, based on the cookie */
440
441	for( r=respref; r->cform; ++r ){
442	if( cookie & r->cform ){
443	for( qq=recres; (q= *qq) != NIL; ++qq ){
444	if( tshape( q, r->mform ) ) goto gotit;
445	}
446	}
447	}
448
449	/* we can't do it; die */
450	cerror( "cannot reclaim");
451
452	gotit:
453
454	if( p->in.op == STARG ) p = p->in.left; /* STARGs are still STARGS */
455
456	q->in.type = p->in.type; /* to make multi-register allocations work */
457	/* maybe there is a better way! */
458	q = tcopy(q);
459
460	tfree(p);
461
462	p->in.op = q->in.op;
463	p->tn.lval = q->tn.lval;
464	p->tn.rval = q->tn.rval;
465	#ifdef FLEXNAMES
466	p->in.name = q->in.name;
467	#ifdef ONEPASS
468	p->in.stalign = q->in.stalign;
469	#endif
470	#else
471	for( i=0; i<NCHNAM; ++i )
472	p->in.name[i] = q->in.name[i];
473	#endif
474
475	q->in.op = FREE;
476
477	/* if the thing is in a register, adjust the type */
478
479	switch( p->in.op ){
480
481	case REG:
482	if( !rtyflg ){
483	/* the C language requires intermediate results to change type */
484	/* this is inefficient or impossible on some machines */
485	/* the "T" command in match supresses this type changing */
486	if( p->in.type == CHAR \|\| p->in.type == SHORT ) p->in.type = INT;
487	else if( p->in.type == UCHAR \|\| p->in.type == USHORT ) p->in.type = UNSIGNED;
262eaf56	488	#if !defined(FORT) && !defined(SPRECC)
e91423bb	489	else if( p->in.type == FLOAT ) p->in.type = DOUBLE;
bd4e35d4	490	#endif
e91423bb RC	491	}
	492	if( ! (p->in.rall & MUSTDO ) ) return; /* unless necessary, ignore it */
	493	i = p->in.rall & ~MUSTDO;
	494	if( i & NOPREF ) return;
	495	if( i != p->tn.rval ){
	496	if( busy[i] \|\| ( szty(p->in.type)==2 && busy[i+1] ) ){
	497	cerror( "faulty register move" );
	498	}
	499	rbusy( i, p->in.type );
	500	rfree( p->tn.rval, p->in.type );
	501	rmove( i, p->tn.rval, p->in.type );
	502	p->tn.rval = i;
	503	}
	504
	505	case OREG:
	506	if( p->in.op == REG \|\| !R2TEST(p->tn.rval) ) {
	507	if( busy[p->tn.rval]>1 && istreg(p->tn.rval) ) cerror( "potential register overwrite");
	508	}
	509	else
	510	if( (R2UPK1(p->tn.rval) != 100 && busy[R2UPK1(p->tn.rval)]>1 && istreg(R2UPK1(p->tn.rval)) )
	511	\|\| (busy[R2UPK2(p->tn.rval)]>1 && istreg(R2UPK2(p->tn.rval)) ) )
	512	cerror( "potential register overwrite");
	513	}
	514
	515	}
	516
3464f46e	517	#ifndef ncopy
e91423bb RC	518	ncopy( q, p ) NODE p, q; {
	519	/* copy the contents of p into q, without any feeling for
	520	the contents */
	521	/* this code assume that copying rval and lval does the job;
	522	in general, it might be necessary to special case the
	523	operator types */
	524	register i;
	525
	526	q->in.op = p->in.op;
	527	q->in.rall = p->in.rall;
	528	q->in.type = p->in.type;
	529	q->tn.lval = p->tn.lval;
	530	q->tn.rval = p->tn.rval;
	531	#ifdef FLEXNAMES
	532	q->in.name = p->in.name;
	533	#ifdef ONEPASS
	534	q->in.stalign = p->in.stalign;
	535	#endif
	536	#else
	537	for( i=0; i<NCHNAM; ++i ) q->in.name[i] = p->in.name[i];
	538	#endif
	539
	540	}
3464f46e	541	#endif
e91423bb RC	542
	543	NODE *
	544	tcopy( p ) register NODE *p; {
	545	/* make a fresh copy of p */
	546
	547	register NODE *q;
	548	register r;
	549
	550	ncopy( q=talloc(), p );
	551
	552	r = p->tn.rval;
	553	if( p->in.op == REG ) rbusy( r, p->in.type );
	554	else if( p->in.op == OREG ) {
	555	if( R2TEST(r) ){
	556	if( R2UPK1(r) != 100 ) rbusy( R2UPK1(r), PTR+INT );
	557	rbusy( R2UPK2(r), INT );
	558	}
	559	else {
	560	rbusy( r, PTR+INT );
	561	}
	562	}
	563
	564	switch( optype(q->in.op) ){
	565
	566	case BITYPE:
	567	q->in.right = tcopy(p->in.right);
	568	case UTYPE:
	569	q->in.left = tcopy(p->in.left);
	570	}
	571
	572	return(q);
	573	}
	574
	575	allchk(){
	576	/* check to ensure that all register are free */
	577
	578	register i;
	579
	580	REGLOOP(i){
	581	if( istreg(i) && busy[i] ){
	582	cerror( "register allocation error");
	583	}
	584	}
	585
	586	}