1. instructions and data only on the concept of the application, in fact, in memory, and there is no difference.
2. When the CPU work, as will a number of binary information instruction, while others act as data, the same information will have a different meaning.
Such as:
1000100111011000
As the instruction: mov ax, bx
As data: 89D8H
3. The distinction is an instruction or data is to distinguish between instructions and data over different time periods, i.e., at the instruction fetch stage (or fetch a microprogram) fetched instruction, fetched in the instruction execution stage (or the corresponding microprogram) namely data.
If the bank address provided by the address sources distinguished by the PC is fetched instruction, the instruction provided by the bank address portion of the address code fetched operands.