a differentiating register to store values that differentiate entries in a section of {TAIL ~ a memory}, wherein each value comprises a bit position, a reference value, and {HEAD ~ a pointer} 
a differentiating register to store values that differentiate entries in a section of { TAIL ~ a memory } , wherein each value comprises a bit position , a reference value , and { HEAD ~ a pointer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD