For counting half clock cycles, {HEAD ~ the interpreter} 30 may double the count of the counter 12 and then add or subtract {TAIL ~ one count} based on the values of the GH and GL signals 
add
For counting half clock cycles , { HEAD ~ the interpreter } 30 may double the count of the counter 12 and then add or subtract { TAIL ~ one count } based on the values of the GH and GL signals
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH