All the CPU does is run programs by fetching instructions from
RAM, evaluating them, and executing them in
sequence. The instructions are numbers of the
binary system, in a special format that is unique
for each machine. The CPU breaks an instruction into parts to see if it has
to do something. For instance, a '1' in a certain position in an instruction
could mean that the CPU would have to load data in from RAM, or that it would
have to add two numbers. After the CPU determines what an instruction is
supposed to do, it tells its component parts what to do to complete the
instruction. The parts of a CPU include the ALU,
Registers, and the
Control Store.