The mask generated from the most significant bits section of the pointer includes {TAIL ~ bits} corresponding to various regions of {HEAD ~ the output mask} 
The mask generated from the most significant bits section of the pointer includes { TAIL ~ bits } corresponding to various regions of { HEAD ~ the output mask }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD