What's Inside a CPU
There are three components of a CPU. The arithmetic unit, the logic unit, and the registers.
The Control Unit (CU) controls the sequence of instructions to be executed and it also manages the flow of data to and from other parts of the computer such as the PC's memory, hard drive, video card or network adapter. It interprets instructions and it regulates the timing of the processor.
The Arithmetic and Logic Unit (ALU) is two components that perform different operations, but in similar ways. The Arithmetic unit processes mathmatical data and spits out results. The logic unit handles additional processing like combination, deletion or interruption processes. This help keeps the processor on-task.
The Registers are special memory elements used by the CPU for storing data temporarily during execution of instruction. For instance, the Instruction Register (IR) holds the instruction being executed. Meanwhile the Process Status Register holds "processor bits" about operations done by ALU. These registers are pseudo memory modules; useful because they don't have to leave the CPU so they are in the same "room" when the ALU or Control unit needs them again.
The Program Counter (PC) holds the address of the next instruction to be executed, and the Instruction Decoder is a device which interprets the instruction to be executed. The Accumulator (ACC) stores the intermediate and final results of calculation. It's the main working area of the ALU.