{TAIL ~ a second logic unit} which logically operates the first data and the second transfer control signal, and outputs the result of {HEAD ~ the logical operation}; and 
{ TAIL ~ a second logic unit } which logically operates the first data and the second transfer control signal , and outputs the result of { HEAD ~ the logical operation } ; and
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH