NT1110
HK 5
Purposes, Functions, and Characteristics of a CPU
Although most tech-savvy people know that the Central Processing Unit is one of the components in the computer, but not many people understand what a CPU actually does. Infact most people would not even know what CPU stands for, if you asked them today. The CPU, or microprocessor, stands for Central Processing Unit. It is a very suitable name because it describes exactly what it does in the computer. The CPU processes instructions that it gathers from decoding the code in programs and other such files. The CPU has four primary functions: fetch, decode, execute, and writeback. In the first step, the CPU retrieves the instruction that it needs to run from program memory. Each instruction in a program (which contains millions of instructions) is stored at a specific address. The CPU has a program counter, which keeps track of the CPU’s position in the program “more specifically, the address of the instruction that the CPU is accessing”. For the next step, it is important to know no matter what code a program is written in, the compiler for that specific language is broken down to the Assembly Language. The Assembly Language is a language that the CPU understands, but may vary to different CPU’s. The “assembler” translates Assembly Language into binary code, which the CPU can manipulate to execute the instructions it is given. Based on the instructions given, the CPU can do one of three things: 1) using the Arithmetic Unit, the CPU can calculate extremely complicated mathematical equations; 2) move data from one memory location to another; 3) jump to different addresses in the program based on decisions made by the CPU itself. Typically, each of actions taken by the CPU produces some sort of output. The CPU takes this output and writes it into the computer’s memory. When these four steps have been completed, the Program Counter moves onto the next instruction and repeats the entire