If {TAIL ~ the vector length} is smaller than the threshold map value, the block 1250 is entered, this block representing the substituting of {HEAD ~ a 0 bit} for the vector 
If { TAIL ~ the vector length } is smaller than the threshold map value , the block 1250 is entered , this block representing the substituting of { HEAD ~ a 0 bit } for the vector
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH