xref: /csrg-svn/old/pcc/ccom.vax/local.c (revision 16181)

static char *sccsid ="@(#)local.c	1.3 (Berkeley) 03/14/84";
# include "mfile1"

/*	this file contains code which is dependent on the target machine */

NODE *
cast( p, t ) register NODE *p; TWORD t; {
	/* cast node p to type t */

	p = buildtree( CAST, block( NAME, NIL, NIL, t, 0, (int)t ), p );
	p->in.left->in.op = FREE;
	p->in.op = FREE;
	return( p->in.right );
	}

NODE *
clocal(p) NODE *p; {

	/* this is called to do local transformations on
	   an expression tree preparitory to its being
	   written out in intermediate code.
	*/

	/* the major essential job is rewriting the
	   automatic variables and arguments in terms of
	   REG and OREG nodes */
	/* conversion ops which are not necessary are also clobbered here */
	/* in addition, any special features (such as rewriting
	   exclusive or) are easily handled here as well */

	register struct symtab *q;
	register NODE *r;
	register o;
	register m, ml;

	switch( o = p->in.op ){

	case NAME:
		if( p->tn.rval < 0 ) { /* already processed; ignore... */
			return(p);
			}
		q = &stab[p->tn.rval];
		switch( q->sclass ){

		case AUTO:
		case PARAM:
			/* fake up a structure reference */
			r = block( REG, NIL, NIL, PTR+STRTY, 0, 0 );
			r->tn.lval = 0;
			r->tn.rval = (q->sclass==AUTO?STKREG:ARGREG);
			p = stref( block( STREF, r, p, 0, 0, 0 ) );
			break;

		case ULABEL:
		case LABEL:
		case STATIC:
			if( q->slevel == 0 ) break;
			p->tn.lval = 0;
			p->tn.rval = -q->offset;
			break;

		case REGISTER:
			p->in.op = REG;
			p->tn.lval = 0;
			p->tn.rval = q->offset;
			break;

			}
		break;

	case PCONV:
		/* do pointer conversions for char and longs */
		ml = p->in.left->in.type;
		if( ( ml==CHAR || ml==UCHAR || ml==SHORT || ml==USHORT ) && p->in.left->in.op != ICON ) break;

		/* pointers all have the same representation; the type is inherited */

	inherit:
		p->in.left->in.type = p->in.type;
		p->in.left->fn.cdim = p->fn.cdim;
		p->in.left->fn.csiz = p->fn.csiz;
		p->in.op = FREE;
		return( p->in.left );

	case SCONV:
		m = (p->in.type == FLOAT || p->in.type == DOUBLE );
		ml = (p->in.left->in.type == FLOAT || p->in.left->in.type == DOUBLE );
		if( m != ml ) break;

		/* now, look for conversions downwards */

		m = p->in.type;
		ml = p->in.left->in.type;
		if( p->in.left->in.op == ICON ){ /* simulate the conversion here */
			CONSZ val;
			val = p->in.left->tn.lval;
			switch( m ){
			case CHAR:
				p->in.left->tn.lval = (char) val;
				break;
			case UCHAR:
				p->in.left->tn.lval = val & 0XFF;
				break;
			case USHORT:
				p->in.left->tn.lval = val & 0XFFFFL;
				break;
			case SHORT:
				p->in.left->tn.lval = (short)val;
				break;
			case UNSIGNED:
				p->in.left->tn.lval = val & 0xFFFFFFFFL;
				break;
			case INT:
				p->in.left->tn.lval = (int)val;
				break;
				}
			p->in.left->in.type = m;
			}
		else
			break;

		/* clobber conversion */
		p->in.op = FREE;
		return( p->in.left );  /* conversion gets clobbered */

	case PVCONV:
	case PMCONV:
		if( p->in.right->in.op != ICON ) cerror( "bad conversion", 0);
		p->in.op = FREE;
		return( buildtree( o==PMCONV?MUL:DIV, p->in.left, p->in.right ) );

	case RS:
	case ASG RS:
		/* convert >> to << with negative shift count */
		/* only if type of left operand is not unsigned */

		if( ISUNSIGNED(p->in.left->in.type) ) break;
		p->in.right = buildtree( UNARY MINUS, p->in.right, NIL );
		if( p->in.op == RS ) p->in.op = LS;
		else p->in.op = ASG LS;
		break;

	case FLD:
		/* make sure that the second pass does not make the
		   descendant of a FLD operator into a doubly indexed OREG */

		if( p->in.left->in.op == UNARY MUL
				&& (r=p->in.left->in.left)->in.op == PCONV)
			if( r->in.left->in.op == PLUS || r->in.left->in.op == MINUS )
				if( ISPTR(r->in.type) ) {
					if( ISUNSIGNED(p->in.left->in.type) )
						p->in.left->in.type = UCHAR;
					else
						p->in.left->in.type = CHAR;
				}
		break;
		}

	return(p);
	}

andable( p ) NODE *p; {
	return(1);  /* all names can have & taken on them */
	}

cendarg(){ /* at the end of the arguments of a ftn, set the automatic offset */
	autooff = AUTOINIT;
	}

cisreg( t ) TWORD t; { /* is an automatic variable of type t OK for a register variable */

#ifdef TRUST_REG_CHAR_AND_REG_SHORT
	if( t==INT || t==UNSIGNED || t==LONG || t==ULONG	/* tbl */
		|| t==CHAR || t==UCHAR || t==SHORT 		/* tbl */
		|| t==USHORT || ISPTR(t)) return(1);		/* tbl */
#else
	if( t==INT || t==UNSIGNED || t==LONG || t==ULONG	/* wnj */
		|| ISPTR(t)) return (1);			/* wnj */
#endif
	return(0);
	}

NODE *
offcon( off, t, d, s ) OFFSZ off; TWORD t; {

	/* return a node, for structure references, which is suitable for
	   being added to a pointer of type t, in order to be off bits offset
	   into a structure */

	register NODE *p;

	/* t, d, and s are the type, dimension offset, and sizeoffset */
	/* in general they  are necessary for offcon, but not on H'well */

	p = bcon(0);
	p->tn.lval = off/SZCHAR;
	return(p);

	}


static inwd	/* current bit offsed in word */;
static word	/* word being built from fields */;

incode( p, sz ) register NODE *p; {

	/* generate initialization code for assigning a constant c
		to a field of width sz */
	/* we assume that the proper alignment has been obtained */
	/* inoff is updated to have the proper final value */
	/* we also assume sz  < SZINT */

	if((sz+inwd) > SZINT) cerror("incode: field > int");
	word |= ((unsigned)(p->tn.lval<<(32-sz))) >> (32-sz-inwd);
	inwd += sz;
	inoff += sz;
	if(inoff%SZINT == 0) {
		printf( "	.long	0x%x\n", word);
		word = inwd = 0;
		}
	}

fincode( d, sz ) double d; {
	/* output code to initialize space of size sz to the value d */
	/* the proper alignment has been obtained */
	/* inoff is updated to have the proper final value */
	/* on the target machine, write it out in octal! */


	printf("	%s	0%c%.20e\n", sz == SZDOUBLE ? ".double" : ".float",
		sz == SZDOUBLE ? 'd' : 'f', d);
	inoff += sz;
	}

cinit( p, sz ) NODE *p; {
	/* arrange for the initialization of p into a space of
	size sz */
	/* the proper alignment has been opbtained */
	/* inoff is updated to have the proper final value */
	ecode( p );
	inoff += sz;
	}

vfdzero( n ){ /* define n bits of zeros in a vfd */

	if( n <= 0 ) return;

	inwd += n;
	inoff += n;
	if( inoff%ALINT ==0 ) {
		printf( "	.long	0x%x\n", word );
		word = inwd = 0;
		}
	}

char *
exname( p ) char *p; {
	/* make a name look like an external name in the local machine */

#ifndef FLEXNAMES
	static char text[NCHNAM+1];
#else
	static char text[BUFSIZ+1];
#endif

	register i;

	text[0] = '_';
#ifndef FLEXNAMES
	for( i=1; *p&&i<NCHNAM; ++i ){
#else
	for( i=1; *p; ++i ){
#endif
		text[i] = *p++;
		}

	text[i] = '\0';
#ifndef FLEXNAMES
	text[NCHNAM] = '\0';  /* truncate */
#endif

	return( text );
	}

ctype( type ){ /* map types which are not defined on the local machine */
	switch( BTYPE(type) ){

	case LONG:
		MODTYPE(type,INT);
		break;

	case ULONG:
		MODTYPE(type,UNSIGNED);
		}
	return( type );
	}

noinit( t ) { /* curid is a variable which is defined but
	is not initialized (and not a function );
	This routine returns the stroage class for an uninitialized declaration */

	return(EXTERN);

	}

commdec( id ){ /* make a common declaration for id, if reasonable */
	register struct symtab *q;
	OFFSZ off, tsize();

	q = &stab[id];
	printf( "	.comm	%s,", exname( q->sname ) );
	off = tsize( q->stype, q->dimoff, q->sizoff );
	printf( CONFMT, off/SZCHAR );
	printf( "\n" );
	}

isitlong( cb, ce ){ /* is lastcon to be long or short */
	/* cb is the first character of the representation, ce the last */

	if( ce == 'l' || ce == 'L' ||
		lastcon >= (1L << (SZINT-1) ) ) return (1);
	return(0);
	}


isitfloat( s ) char *s; {
	double atof();
	dcon = atof(s);
	return( FCON );
	}

ecode( p ) NODE *p; {

	/* walk the tree and write out the nodes.. */

	if( nerrors ) return;
	p2tree( p );
	p2compile( p );
	}

#ifndef ONEPASS
tlen(p) NODE *p;
{
	switch(p->in.type) {
		case CHAR:
		case UCHAR:
			return(1);

		case SHORT:
		case USHORT:
			return(2);

		case DOUBLE:
			return(8);

		default:
			return(4);
		}
	}
#endif