The central processing unit includes: arithmetic unit and controller. The arithmetic unit refers to the component in the computer that performs various arithmetic and logical operations. The arithmetic logic unit is part of the central processing core; the controller refers to changing the wiring of the main circuit or control circuit and changing the resistance value in the circuit in a predetermined sequence. The master device that controls the starting, speed regulation, braking and reversal of the motor.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
Central processing unit (CPU) is one of the main devices of electronic computers and the core component of computers. Its function is mainly to interpret computer instructions and process data in computer software. The CPU is the core component of the computer that reads instructions, decodes them, and executes them. The central processing unit mainly consists of two parts, namely the controller and the arithmetic unit, which also include cache memory and the data and control bus that realize the connection between them. The three core components of an electronic computer are the CPU, internal memory, and input/output devices. The main functions of the central processing unit are to process instructions, perform operations, control time, and process data.
In the computer architecture, the CPU is the core hardware unit that controls and allocates all hardware resources of the computer (such as memory, input and output units) and performs general operations. The CPU is the computing and control core of the computer. The operations of all software layers in the computer system will eventually be mapped to CPU operations through the instruction set.
For the central processing unit, it can be regarded as a large-scale integrated circuit, and its main task is to process and process various data. The storage capacity of traditional computers is relatively small, which makes it difficult to process large-scale data, and the processing effect is relatively low. With the rapid development of my country's information technology level, high-configuration processor computers have emerged. High-configuration processors are used as control centers and play an important role in improving the structure and function of computer CPUs. The core part of the central processing unit is the controller and arithmetic unit, which plays an important role in improving the overall function of the computer. It can realize the proliferation of multiple functions such as register control, logical operations, and signal transmission and reception, laying a good foundation for improving the performance of the computer. Base.
Integrated circuits play a role in regulating signals within the computer and perform different instruction tasks according to user operation instructions. The central processing unit is a very large-scale integrated circuit. It consists of arithmetic units, controllers, registers, etc., as shown in the figure below. The key operation lies in the processing and processing of various types of data.
Traditional computers have small storage capacity and low operating efficiency when faced with large-scale data sets. The new generation of computers uses high-configuration processors as the control center, and the CPU has great room for improvement in terms of structure and function. The central processing unit uses arithmetic units and controllers as its main devices, and gradually expands into multiple functions such as logical operations, register control, program coding, and signal transmission and reception. These speed up the optimization and upgrade of CPU control performance.
Core part
Operator
Operator refers to various arithmetic in the computer and components for logical operation operations, where the arithmetic logic unit is part of the central processing core.
(1) Arithmetic logic unit (ALU). Arithmetic logic unit refers to a combinational logic circuit that can realize multiple sets of arithmetic operations and logical operations. It is an important part of central processing. The operations of the arithmetic logic unit are mainly two-bit arithmetic operations, such as addition, subtraction, and multiplication. During the operation process, the arithmetic logic unit mainly performs arithmetic and logical operations using computer instructions. Generally speaking, the ALU can play the role of direct read-in and read-out, which is specifically reflected in the processor controller, memory and input and output devices. , input and output are implemented based on the bus. The input command contains an instruction word, including operation code, format code, etc.
(2) Intermediate register (IR). Its length is 128 bits, and its actual length is determined by the operands. IR plays an important role in the "push and fetch" instruction. During the execution of this instruction, the content of ACC is sent to IR, then the operand is fetched to ACC, and then the content of IR is pushed onto the stack.
(3) Operation accumulator (ACC). Current registers are generally single accumulators with a length of 128 bits. For ACC, it can be regarded as a variable-length accumulator. In the process of describing instructions, the expression of ACC length is generally based on the value of ACS, and the ACS length is directly related to the ACC length. Doubling or halving the ACS length can also be regarded as doubling or halving the ACC length.
(4) Descriptor register (DR). It is mainly used to store and modify descriptors. The length of DR is 64 bits. In order to simplify data structure processing, the use of descriptors plays an important role.
(5)B register. It plays an important role in the modification of instructions. The length of the B register is 32 bits. It can save the address modification amount during the address modification process. The main memory address can only be modified using descriptors. The descriptor points to the first element in the array, so accessing other elements in the array should require modifiers. For arrays, they are composed of data of the same size or elements of the same size and are stored continuously. The common access method is the vector descriptor, because the address in the vector descriptor is a byte address, so when proceeding During the conversion process, the base addresses should first be added. For the conversion work, it is mainly implemented automatically by the hardware. In this process, special attention must be paid to alignment to avoid exceeding the array boundaries.
Controller
The controller refers to changing the wiring of the main circuit or control circuit in a predetermined sequence and changing the resistance value in the circuit to control the starting, speed regulation, and Braking and reverse master device. The controller is composed of program status register PSR, system status register SSR, program counter PC, instruction register, etc. As a "decision-making mechanism", its main task is to issue commands and play a coordination and command role in the operation of the entire computer system. There are two main categories of control: combinational logic controllers and microprogrammed controllers. Both parts have their own advantages and disadvantages. Among them, the structure of the combinational logic controller is relatively complex, but its advantage is that it is faster; the microprogrammed controller design has a simple structure, but when modifying the function of a machine instruction, the entire microprogram needs to be reprogrammed.
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