macro
	loopBody640 &iters
	lcla	&n
.top
	ldx	|4*&n,Y
	lda	>BCT640A,X
	ldx	|4*&n+2,Y
	ora	>BCT640B,X
	LDX	destOfst
	STA	>destBuf+&n,X
&n	seta	&n+1
	aif	&n<&iters,.top
	mend