{HEAD ~ Appropriate registers} are provided to store the numbers which represent the subtrahend and {TAIL ~ minuend} of a subtraction operation 
{ HEAD ~ Appropriate registers } are provided to store the numbers which represent the subtrahend and { TAIL ~ minuend } of a subtraction operation
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH