(PC) A register in the central processing unit that contains the addresss of the next instruction to be executed. After each instruction is fetched, the PC is automatically incremented to point to the following instruction. It is not normally manipulated like an ordinary register but instead, special instructions are provided to alter the flow of control by writing a new value to the PC, e.g. JUMP, CALL, RTS.
IBM call it the Instruction Address Register.
When the transfer takes place, the program counter holds the address of the instruction following the jsp.
The program counter holds the memory location of the next instruction to be executed.