What is the CPU of a computer?

The CPU of a computer refers to the central processing unit, which is the arithmetic unit and controller of the computer. The CPU includes arithmetic logic components, register components, control components, etc. The arithmetic logic component can perform fixed-point or floating-point arithmetic operations. , shift operations and logical operations, and can also perform address operations and conversions.

#The operating environment of this article: Windows 7 system, Dell G3 computer.

CPU is the central processing unit. Is the computer's arithmetic unit and controller

CPU includes arithmetic logic components, register components and control components, English Logic components; arithmetic logic components, which can perform fixed-point or floating-point arithmetic operations, shift operations and logic operations, and can also perform address operations and conversions.

1. Register

Register components include general-purpose registers, special-purpose registers and control registers.

General-purpose registers can be divided into fixed-point numbers and floating-point numbers. They are used to save register operands temporarily stored during instruction execution and intermediate (or final) operation results.

General-purpose registers are an important part of the CPU, and most instructions access general-purpose registers. The width of the general-purpose register determines the width of the data path inside the computer, and the number of its ports can often affect the parallelism of internal operations.

Special-purpose registers are registers needed to perform some special operations.

The control registers (CR0~CR3) are used to control and determine the operating mode of the processor and the characteristics of the currently executing tasks. CR0 contains system control flags that control the operating mode and status of the processor; CR1 is reserved; CR2 contains the linear address that causes page faults; CR3 contains the physical memory base address of the page directory table, so this register is also called the page directory base address Register PDBR (Page-Directory Base address Register).

2. Control unit

English Control unit; the control unit is mainly responsible for decoding instructions and issuing the various operations to be performed to complete each instruction. control signal.

There are two structures: one is a micro-program control method with micro-storage as the core; the other is a control method based on a logical hard-wiring structure.

Microcode is maintained in micro storage. Each microcode corresponds to one of the most basic micro-operations, also called microinstructions. Each instruction is composed of a different sequence of microcodes. This microcode sequence constitutes a microcode. program. After the central processor decodes the instruction, it sends out a certain sequence of control signals and executes several micro-operations determined by these microcodes in a given sequence and in microcycles to complete the execution of an instruction.

Simple instructions are composed of (3 to 5) micro-operations, while complex instructions are composed of dozens or even hundreds of micro-operations.

Main function editor

3. Processing instructions

Intel and AMD mainstream CPUs and CPU sockets

English Processing instructions; This refers to the order in which the instructions in the control program are executed. There is a strict sequence between the instructions in the program, and they must be executed strictly in the order specified by the program to ensure the correctness of the computer system.

4. Perform an action

English Perform an action; the function of an instruction is often implemented by components in the computer executing a sequence of operations. The CPU should generate corresponding operation control signals according to the function of the instruction and send them to the corresponding components, thereby controlling these components to act according to the requirements of the instruction.

5. Control time

English Control time; time control is to implement time timing for various operations. During the execution of an instruction, what operations are performed at what time should be strictly controlled. Only in this way can the computer work in an orderly manner.

6. Processing data

That is, performing arithmetic operations and logical operations on data, or performing other information processing.

Its function is mainly to interpret computer instructions, process data in computer software, and execute instructions. In a microcomputer, it is also called a microprocessor. All operations of the computer are controlled by the CPU. The performance indicators of the CPU directly determine the performance indicators of the microcomputer system. The CPU has the following four basic functions: data communication, resource sharing, distributed processing, and providing system reliability. The operating principle can be basically divided into four stages: Fetch, Decode, Execute and Writeback.

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