In response to this comparison, the interpreter 30 adjusts the value of the pulse count {HEAD ~ Data1} by adding or subtracting from {TAIL ~ the pulse count} 
by subtracting from
In response to this comparison , the interpreter 30 adjusts the value of the pulse count { HEAD ~ Data1 } by adding or subtracting from { TAIL ~ the pulse count }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL