logic coupled to {HEAD ~ the differentiating register} to determine {TAIL ~ which entry} is most likely to match a search key and 
to determine
logic coupled to { HEAD ~ the differentiating register } to determine { TAIL ~ which entry } is most likely to match a search key and
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH