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