local2.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

		s = talloc();
		rt = r->in.type;

		s->in.op = SCONV;
		s->in.left = l;
		s->in.type = rt;
		zzzcode(s, 'A');
		putstr("\n\t");

		hopcode(rt == FLOAT ? 'F' : 'D', p->in.op);
		putstr("2\t");
		adrput(r);
		putchar(',');
		adrput(resc);
		putstr("\n\t");

		s->in.op = ASSIGN;
		s->in.left = l;
		s->in.right = resc;
		s->in.type = l->in.type;
		zzzcode(s, 'A');

		s->in.op = FREE;
		return;
		}

	case 'B':	/* get oreg value in temp register for left shift */
		{
		register NODE *r;
		if (xdebug) eprint(p, 0, &val, &val);
		r = p->in.right;
		if( tlen(r) == sizeof(int) && r->in.type != FLOAT )
			putstr("movl");
		else {
			putstr("cvt");
			prtype(r);
			putchar('l');
			}
		return;
		}

	case 'C':	/* num words pushed on arg stack */
		{
		extern int gc_numbytes;
		extern int xdebug;

		if (xdebug) printf("->%d<-",gc_numbytes);

		printf("$%d", gc_numbytes/(SZLONG/SZCHAR) );
		return;
		}

	case 'D':	/* INCR and DECR */
		zzzcode(p->in.left, 'A');
		putchar('\n');
		putchar('\t');

	case 'E':	/* INCR and DECR, FOREFF */
		if (p->in.right->tn.lval == 1)
			{
			putstr( p->in.op == INCR ? "inc" : "dec" );
			prtype(p->in.left);
			putchar('\t');
			adrput(p->in.left);
			return;
			}
		putstr( p->in.op == INCR ? "add" : "sub" );
		prtype(p->in.left);
		putchar('2');
		putchar('\t');
		adrput(p->in.right);
		putchar(',');
		adrput(p->in.left);
		return;

	case 'F':	/* register type of right operand */
		{
		register NODE *n;
		extern int xdebug;
		register int ty;

		n = getlr( p, 'R' );
		ty = n->in.type;

		if (xdebug) printf("->%d<-", ty);

		if ( ty==DOUBLE)
		    {

		    /*
		     * 	If -M flag is set then use gfloat suffix
		     *
		     */

		    if ( Mflag )			/* slr001 */
			putchar('g');			/* slr001 */
		    else				/* slr001 */
			 putchar('d');			/* slr001 */

		    }

		else if ( ty==FLOAT ) putchar('f');
		else putchar('l');
		return;
		}

	case 'L':	/* type of left operand */
	case 'R':	/* type of right operand */
		{
		register NODE *n;
		extern int xdebug;

		n = getlr( p, c );
		if (xdebug) printf("->%d<-", n->in.type);

		prtype(n);
		return;
		}

	case 'Z':	/* complement mask for bit instr */
		printf("$%ld", ~p->in.right->tn.lval);
		return;

	case 'U':	/* 32 - n, for unsigned right shifts */
		printf("$%d", 32 - p->in.right->tn.lval );
		return;

	case 'T':	/* rounded structure length for arguments */
		{
		int size;

		size = p->stn.stsize;
		SETOFF( size, 4);
		printf("$%d", size);
		return;
		}

	case 'S':  /* structure assignment */
		{
			register NODE *l, *r;
			register size;

			if( p->in.op == STASG ){
				l = p->in.left;
				r = p->in.right;

				}
			else if( p->in.op == STARG ){  /* store an arg into a temporary */
				l = getlr( p, '3' );
				r = p->in.left;
				}
			else cerror( "STASG bad" );

			if( r->in.op == ICON ) r->in.op = NAME;
			else if( r->in.op == REG ) r->in.op = OREG;
			else if( r->in.op != OREG ) cerror( "STASG-r" );

			size = p->stn.stsize;

			if( size <= 0 || size > 65535 )
				cerror("structure size <0=0 or >65535");

			switch(size) {
				case 1:
					putstr("	movb	");
					break;
				case 2:
					putstr("	movw	");
					break;
				case 4:
					putstr("	movl	");
					break;
				case 8:
					putstr("	movq	");
					break;
				default:
					printf("	movc3	$%d,", size);
					break;
			}
			adrput(r);
			putchar(',');
			adrput(l);
			putchar('\n');

			if( r->in.op == NAME ) r->in.op = ICON;
			else if( r->in.op == OREG ) r->in.op = REG;

			}
		break;

	case 'V':	/* slr001 Data type used for float instruction */

		/*
		 *	If Mflag is set it indicates that gfloat instruction
		 *	are wanted
		 *	
		 */

	        if ( Mflag )			/* slr001 */
		    putchar('g');			/* slr001 */
		else					/* slr001 */
		    putchar('d');			/* slr001 */

		break;					/* slr001 */

	case 'W':	
		/* 	vdp004 Data type used for float instruction  either
		 * 	f, d, or g. 
		 *	If Mflag is set it indicates that gfloat instruction
		 *	are wanted
		 *	If fflag is set it indicates that floating point 
		 *	arithmetic should be done in float.
		 *	
		 */

		if (fflag)
		  /* call prtype to give it a chance to print 
		   * out float vdp04 
		   */
		    prtype(p) ;				/* vdp004  */ 
	        else if ( Mflag )			/* vdp004 */
		    putchar('g');			/* vdp004  */
		else					/* vdp004  */
		    putchar('d');			/* vdp004  */

		break;					/* vdp004  */

	default:
		cerror( "illegal zzzcode" );
		}
	}

/*
 * collapsible(dest, src) -- if a conversion with a register destination
 *	can be accomplished in one instruction, return the type of src
 *	that will do the job correctly; otherwise return 0.  Note that
 *	a register must always end up having type INT or UNSIGNED.
 */
int
collapsible(dest, src)
NODE *dest, *src;
{
	int st = src->in.type;
	int dt = dest->in.type;
	int newt = 0;

	/*
	 * Are there side effects of evaluating src?
	 * If the derived type will not be the same size as src,
	 * we may have to use two steps.
	 */
	if (tlen(src) > tlen(dest)) {
		if (tshape(src, STARREG))
			return (0);
		if (src->in.op == OREG && R2TEST(src->tn.rval))
			return (0);
		}

	/*
	 * Can we get an object of dest's type by punning src?
	 * Praises be to great Cthulhu for little-endian machines...
	 */
	if (st == CHAR && dt == USHORT)
		/*
		 * Special case -- we must sign-extend to 16 bits.
		 */
		return (0);

	if (tlen(src) < tlen(dest))
		newt = st;
	else
		newt = dt;

	return (newt);
	}

rmove( rt, rs, t ) TWORD t; {
	printf( "	%s	%s,%s\n",
#ifdef FORT
		!Oflag ? (t==DOUBLE ? "movq" : "movl") :
#endif
		(t==FLOAT ? "movf" :			/* slr001 */
			(t==DOUBLE ? ( Mflag ? "movg" : "movd" ) : "movl")),
		rnames[rs], rnames[rt] );
	}

struct respref
respref[] = {
	INTAREG|INTBREG,	INTAREG|INTBREG,
	INAREG|INBREG,	INAREG|INBREG|SOREG|STARREG|STARNM|SNAME|SCON,
	INTEMP,	INTEMP,
	FORARG,	FORARG,
	INTEMP,	INTAREG|INAREG|INTBREG|INBREG|SOREG|STARREG|STARNM,
	0,	0 };

setregs(){ /* set up temporary registers */
	fregs = 6;	/* tbl- 6 free regs on VAX (0-5) */
	;
	}

szty(t){ 
	/* size, in registers, needed to hold thing of type t
	 *vdp004 for f floats with fflag only need 1 register
	 */

	if (fflag)					 
		return (  (t==DOUBLE) ? 2 : 1 ); 
	else
		return( (t==DOUBLE||t==FLOAT) ? 2 : 1 );
	}

rewfld( p ) NODE *p; {
	return(1);
	}

callreg(p) NODE *p; {
	return( R0 );
	}

base( p ) register NODE *p; {
	register int o = p->in.op;

	if( (o==ICON && p->in.name[0] != '\0')) return( 100 ); /* ie no base reg */
	if( o==REG ) return( p->tn.rval );
    if( (o==PLUS || o==MINUS) && p->in.left->in.op == REG && p->in.right->in.op==ICON)
		return( p->in.left->tn.rval );
    if( o==OREG && !R2TEST(p->tn.rval) && (p->in.type==INT || p->in.type==UNSIGNED || ISPTR(p->in.type)) )
		return( p->tn.rval + 0200*1 );
	if( o==INCR && p->in.left->in.op==REG ) return( p->in.left->tn.rval + 0200*2 );
	if( o==ASG MINUS && p->in.left->in.op==REG) return( p->in.left->tn.rval + 0200*4 );
	if( o==UNARY MUL && p->in.left->in.op==INCR && p->in.left->in.left->in.op==REG
	  && (p->in.type==INT || p->in.type==UNSIGNED || ISPTR(p->in.type)) )
		return( p->in.left->in.left->tn.rval + 0200*(1+2) );
	return( -1 );
	}

offset( p, tyl ) register NODE *p; int tyl; {

	if( tyl==1 &&
	    p->in.op==REG &&
	    (p->in.type==INT || p->in.type==UNSIGNED) )
		return( p->tn.rval );
	if( p->in.op==LS &&
	    p->in.left->in.op==REG &&
	    (p->in.left->in.type==INT || p->in.left->in.type==UNSIGNED) &&
	    p->in.right->in.op==ICON &&
	    p->in.right->in.name[0]=='\0' &&
	    (1<<p->in.right->tn.lval)==tyl)
		return( p->in.left->tn.rval );
	return( -1 );
	}

makeor2( p, q, b, o) register NODE *p, *q; register int b, o; {
	register NODE *t;
	register int i;
	NODE *f;

	p->in.op = OREG;
	f = p->in.left; 	/* have to free this subtree later */

	/* init base */
	switch (q->in.op) {
		case ICON:
		case REG:
		case OREG:
			t = q;
			break;

		case MINUS:
			q->in.right->tn.lval = -q->in.right->tn.lval;
		case PLUS:
			t = q->in.right;
			break;

		case INCR:
		case ASG MINUS:
			t = q->in.left;
			break;

		case UNARY MUL:
			t = q->in.left->in.left;
			break;

		default:
			cerror("illegal makeor2");
	}

	p->tn.lval = t->tn.lval;
#ifndef FLEXNAMES
	for(i=0; i<NCHNAM; ++i)
		p->in.name[i] = t->in.name[i];
#else
	p->in.name = t->in.name;
#endif

	/* init offset */
	p->tn.rval = R2PACK( (b & 0177), o, (b>>7) );

	tfree(f);
	return;
	}

canaddr( p ) NODE *p; {
	register int o = p->in.op;

	if( o==NAME || o==REG || o==ICON || o==OREG || (o==UNARY MUL && shumul(p->in.left)) ) return(1);
	return(0);
	}

shltype( o, p ) register NODE *p; {
	return( o== REG || o == NAME || o == ICON || o == OREG || ( o==UNARY MUL && shumul(p->in.left)) );
	}

flshape( p ) register NODE *p; {
	return( p->in.op == REG || p->in.op == NAME || p->in.op == ICON ||
		(p->in.op == OREG && (!R2TEST(p->tn.rval) || tlen(p) == 1)) );
	}

shtemp( p ) register NODE *p; {
	if( p->in.op == STARG ) p = p->in.left;
	return( p->in.op==NAME || p->in.op ==ICON || p->in.op == OREG || (p->in.op==UNARY MUL && shumul(p->in.left)) );
	}

shumul( p ) register NODE *p; {
	register o;
	extern int xdebug;

	if (xdebug) {
		 printf("\nshumul:op=%d,lop=%d,rop=%d", p->in.op, p->in.left->in.op, p->in.right->in.op);
		printf(" prname=%s,plty=%d, prlval=%D\n", p->in.right->in.name, p->in.left->in.type, p->in.right->tn.lval);
		}


	o = p->in.op;
	if( o == NAME || (o == OREG && !R2TEST(p->tn.rval)) || o == ICON ) return( STARNM );

	if( ( o == INCR || o == ASG MINUS ) &&
	    ( p->in.left->in.op == REG && p->in.right->in.op == ICON ) &&
	    p->in.right->in.name[0] == '\0' )
		{
		switch (p->in.type)
			{
			case CHAR|PTR:
			case UCHAR|PTR:
				o = 1;
				break;

			case SHORT|PTR:
			case USHORT|PTR:
				o = 2;
				break;

			case INT|PTR:
			case UNSIGNED|PTR:
			case LONG|PTR:
			case ULONG|PTR:
			case FLOAT|PTR:
				o = 4;
				break;

			case DOUBLE|PTR:
				o = 8;
				break;

			default:
				/*
				 * To fix the problem when the increment
				 * of a structure class is a register
				 * and is part of a condition test.
				 */

				if ( (ISPTR(p->in.left->in.type)) && /*RAP003*/
				     (p->in.type == p->in.left->in.type))
				    {
				    o = p->in.right->tn.lval;
				    if (o==1|o==2|o==4|o==8)
					return(STARREG);
				    }
				return(0);
			}
		return( p->in.right->tn.lval == o ? STARREG : 0);
		}

	return( 0 );
	}

adrcon( val ) CONSZ val; {
	putchar( '$' );
	printf( CONFMT, val );
	}

conput( p ) register NODE *p; {
	switch( p->in.op ){

	case ICON:
		acon( p );