Q. What is control function?
If transfer is to take place only under a predetermined control condition then this condition can be specified as a control function. For illustration if P is a control function then P is a Boolean variable which can have a value of 0 or 1. It is terminated by a colon (:) and placed in front of actual transfer statement. Operation specified in statement occurs only when P = 1. Consider the statements:
If (P =1) then (R2←R1)
Or,
P: R2←R1,
Where P is a control function that can be either 0 or 1.