In a modern computer, the instructions are in a process control block, which is stored in memory, not the CPU . Technically, they tend to be stored in logical memory, where part is in a backing store and part is in physical memory, but it appears to be all real memory to the CPU . So, that would be like a separate Turing machine all together that sends information to the CPU . Trying to simplify a CPU down to a Turing machine requires you to ignore the complexities.
