A stored$-$program computer requires a memory or register to store the address of the current

instruction to be executed. For historical reasons this register is often referred to as the program

counter $($PC$).$ On each clock cycle, an instruction is fetched from memory $($from the address specified

by the PC$)$ and the PC is updated to contain the address of the next instruction $($i$.$e$.,$ the instruction to

be fetched on the next clock cycle$).$ Figure $1$ illustrates the portion of a CPUs datapath for managing

the program counter.