"Op2" is expanded to one of:-
	(1)	<reg>
	(2)	<reg> RRX
	(3)	<reg> <s-op> <reg>
	(4)	<reg> <s-op> #<expr>
	(5)	#<expr>

Where "<s-op>" is one of:-
	(a)	ROR
	(b)	LSR
	(c)	ASR
	(d)	LSL
	(e)	ASL