In this circuit, the number of {HEAD ~ guard bits} required to guarantee {TAIL ~ round off accuracy} is only two 
In this circuit , the number of { HEAD ~ guard bits } required to guarantee { TAIL ~ round off accuracy } is only two
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH