///  a7 -- pdp-11 assembler pass 1expres:	mov	r5,-(sp)	mov	$'+,-(sp)	clr	opfound	clr	r2	mov	$1,r3	br	1fadvanc:	jsr	pc,readop1:	mov	r4,r0	jsr	r5,betwen; 0; 177		br .+4	br	7f	movb	(r4),r0	mov	2(r4),r1	br	oprand7:	cmp	r4,$141	blo	1f	cmp	r4,$141+10.	bhis	2f	movb	curfbr-141(r4),r0	asl	r4	mov	curfb-[2*141](r4),r2	cmp	r2,$-1	bne	oprand	jsr	r5,error; 'f	br	oprand2:	clr	r3	clr	r2	br	oprand1:	mov	$esw1,r11:	cmp	(r1)+,r4	beq	1f	tst	(r1)+	bne	1b	tst	opfound	bne	2f	jsr	pc,errore2:	tst	(sp)+	mov	(sp)+,r5	rts	pc1:	jmp	*(r1)esw1:	'+;	binop	'-;	binop	'*;	binop	'/;	binop	'&;	binop	037;	binop	035;	binop	036;	binop	'%;	binop	'[;	brack	'^;	binop	1;	exnum	'!;	binop	0;	0binop:	cmpb	(sp),$'+	beq	1f	jsr	pc,errore1:	movb	r4,(sp)	br	advancexnum:	mov	numval,r1	mov	$1,r0	br	oprandbrack:	mov	r2,-(sp)	mov	r3,-(sp)	jsr	pc,readop	jsr	pc,expres	cmp	r4,$']	beq	1f	jsr	r5,error; ']1:	mov	r3,r0	mov	r2,r1	mov	(sp)+,r3	mov	(sp)+,r2oprand:	inc	opfound	mov	$exsw2,r51:	cmp	(sp),(r5)+	beq	1f	tst	(r5)+	bne	1b	br	eoprnd1:	jmp	*(r5)exsw2:	'+; exadd	'-; exsub	'*; exmul	'/; exdiv	037; exor	'&; exand	035;exlsh	036;exrsh	'%; exmod	'!; exnot	'^; excmbin	0;  0excmbin:	mov	r0,r3			/ give left flag of right	br	eoprndexrsh:	neg	r1	beq	exlsh	inc	r1	clc	ror	r2exlsh:	jsr	r5,combin; 0	als	r1,r2	br	eoprndexmod:	jsr	r5,combin; 0	mov	r1,-(sp)	mov	r2,r1	clr	r0	dvd	(sp)+,r0	mov	r1,r2	br	eoprndexadd:	jsr	r5,combin; 0	add	r1,r2	br	eoprndexsub:	jsr	r5,combin; 1	sub	r1,r2	br	eoprndexand:	jsr	r5,combin; 0	com	r1	bic	r1,r2	br	eoprndexor:	jsr	r5,combin; 0	bis	r1,r2	br	eoprndexmul:	jsr	r5,combin; 0	mpy	r2,r1	mov	r1,r2	br	eoprndexdiv:	jsr	r5,combin; 0	mov	r1,-(sp)	mov	r2,r1	clr	r0	dvd	(sp)+,r0	mov	r0,r2	br	eoprndexnot:	jsr	r5,combin; 0	com	r1	add	r1,r2	br	eoprndeoprnd:	mov	$'+,(sp)	jmp	advanccombin:	mov	r0,-(sp)	bis	r3,(sp)	bic	$!40,(sp)	bic	$!37,r0	bic	$!37,r3	cmp	r0,r3	ble	1f	mov	r0,-(sp)	mov	r3,r0	mov	(sp)+,r31:	tst	r0	beq	1f	tst	(r5)+	beq	2f	cmp	r0,r3	bne	2f	mov	$1,r3	br	2f1:	tst	(r5)+	clr	r32:	bis	(sp)+,r3	rts	r5