Microprocessors serve as the central processing unit in a computer system and are involved in the actual execution of machine instructions. Instructions stored in the memory of a computer tell the microprocessors what to do and how to do it. A component of the microprocessor called the arithmetic/logic unit performs arithmetic operations such as addition, subtraction, multiplication and division. Microprocessors also transfer data from one memory location to another.
Logical operations performed by the arithmetic/logic unit include jumping to execute a specific set of instructions if certain conditions are valid. The fetch-decode-execute cycle sums up a successful operation of the microprocessor. During the fetch phase, the microprocessor collects and stores in its own temporary memory data and instructions that tell it what to do with the data. The main memory of the computer stores the data and instructions permanently. During the decode phase, the microprocessor interprets the instructions and prepares several components within the chip for the next phase. The microprocessor performs an operation on the fetched data in line with the provided instructions during the execute stage. After execution, the CPU resets in readiness for another fetch-decode-execute cycle.
Parts of the microprocessor include an address bus, data bus, a read-and-write line, a clock line and a reset line.