sentences:  If this condition holds, the control unit will stall the instruction by one clock cycle.It also stalls the instruction in the fetch stage, to prevent the instruction in that stage from being overwritten by the next instruction in the program.In a Von Neumann architecture which uses the program counter (PC) register to determine the current instruction being fetched in the pipeline, to prevent new instructions from being fetched when an instruction in the decoding stage has been stalled, the value in the PC register and the instruction in the fetch stage are preserved to prevent changes.