In this scheme, look up {TAIL ~ table} of Φv1 or Φv2 is selected based on the output from the logical OR gate by feeding this output to the chip selection pin of {HEAD ~ the ROM chips} 
In this scheme , look up { TAIL ~ table } of Φv1 or Φv2 is selected based on the output from the logical OR gate by feeding this output to the chip selection pin of { HEAD ~ the ROM chips }
OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD