What Any Instruction Register Can Contain

An instruction can include the data that is going to act on, or it can include an address which points to the location where the data can be found. Another thing that the instruction registered can contain are special signals for selecting which instruction will follow from the current one. These are called branching signals. And also, the instruction register may also contain immediate values, which could be memory addresses or just straight up values that the operation is to be performed on. It's essentially tells the process what to do now, what to do next, and what to do it on.