(PC, or "instruction address register") A
register in the
central processing unit that contains the
addresss of the next instruction to be executed. The PC is
automatically incremented after each instruction is fetched 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.