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