if tok.ScanToken == scanner.Ident && p.atStartOfRegister(name) {
		if p.atRegisterShift() {
			// ARM shifted register such as R1<<R2 or R1>>2.
			a.Type = obj.TYPE_SHIFT
			a.Offset = p.registerShift(tok.String(), prefix)
			if p.peek() == '(' {
				// Can only be a literal register here.
				p.next()
				tok := p.next()
				name := tok.String()
				if !p.atStartOfRegister(name) {