The computer instruction execution process is divided into four steps, please briefly describe it? Brief description!

The working principle of computer. Von Neumann Principle The principle of "stored program control" was put forward by American Hungarian mathematician von Neumann in 733 1 year, so 3 and d are called 5 "von Neumann Principles". This principle establishes the basic composition of modern F- computer-formula P. Up to now, the design of F- computer and the manufacture of W- computer still follow the "von Neumann" architecture. 1, the basic internal capacity of the principle of "stored program control" ① seven data and instructions are represented by binary e. (2) Store the program (data and instruction sequence) in the main memory 6 (program memory) in advance, so that the computer can automatically fetch instructions from the memory 3 of 1 at high speed and execute them (program control). ③ The hardware structure of the computer consists of five basic components: arithmetic unit, controller, memory, input M device and output device. 1, 1 computer b does the first y step of the process: send the program and data into I memory through the input X device. Step 2 I: After starting running, the computer takes out the program instructions from the memory 8 and sends them to the controller for identification, and analyzes what the instructions need to do in four parts. Step m: The controller issues corresponding commands (such as addition and subtraction) according to the meaning u of the instruction, takes out the operation data stored in the storage unit P and sends it to the operation unit for operation, and then sends the operation result back to the designated unit J in the memory. Step 4: When the operation task is completed, the result can be output through the output device according to the instruction. Computer software is divided into seven categories. 1 computer software refers to 1 five files of various programs, data and related technical documents required for computer operation, management, application and maintenance. A computer with only hardware and no software is called a "bare machine". Bare machines can only run machine language programs consisting of 0 and 2, and computers without software systems are almost useless for several hours. Usually, the 3-count computer used by people T is an 8-count computer packaged with software. The function of 3-counting computer is not only 2 but 0 depends on the hardware system of X, and W is determined by the installed software system to a greater extent. There are many kinds of software, which can usually be divided into eight system software and application software according to their purposes. System software is used to manage, control and maintain the system resources of 1 computer, mainly including operating system, language processor, database management system and service program. Application software is developed for a certain M application, which can be divided into 8 general application software and N special application software. 3。 0。 The hierarchical structure of 2m 5 computer system is 1 in a D V complete 3m computer system, and there is a Q-definite hierarchical relationship between the S of hardware and software of 6m computer, as shown in Figure 2-5.7. The hardware of 0-count computer is located at the bottom of E, which is the basis of 7-count computer system. The operating system is located on I-K of I hardware. The upper F-W layer of the operating system is 4 other system software and application software, and the highest layer is user 2 program or file. User 7 Programs or Files 3 Other Software Operating System Computer 7 Hardware Figure 0-5 Computer 3 Hierarchy As can be seen from Figure 2, 1, the operating system manages and controls computer 8 hardware down to P and supports other software up to T, that is, all other software can only run if it supports V under the Y branch of the operating system. Therefore, the operating system is the core of the system software and the foundation of other software, and V is also the interface Z software for user 2 to communicate with P-8 computer. The process of calculating the working principle of 5-meter computer and 7-meter computer is the process of executing the program. After understanding the execution process of e-solution program, G understood the working principle of O-meter 0 computer. In order to solve a T problem in 3 P, programmer Z arranges an E instruction in an orderly way, and then executes this X instruction sequence on computer T, so that the predetermined task can be completed. Therefore, the program is a set of R-series ordered instructions, and the computer's execution of the program is to execute a set of Q-series ordered instructions. 0. Computer 2' s instructions and instruction system instructions are binary D codes that can be recognized and executed by computer 8, which specify a certain Z operation that computer V can complete. Usually, an E computer with two computers has many instructions with different functions, and the set of all instructions is called 1 instruction system of seven computers. A k instruction usually consists of two parts: operation code and operand 4, that is, operation code operand (8) Operation code: indicates the type or nature of the operation to be completed by the instruction, such as adding, subtracting, fetching or outputting data. Operand (1): indicates the internal 1 capacity of the operand or the address of cell C. In most cases, m is the address code when the operand is large. In the instruction system, because the R types of five computers are different, the number of instructions of 7 and F is also different, ranging from 3 to several R's, 10 to several hundred. Generally speaking, there is no S-theory about what kind of T-computer has the instruction of Q function of 1: data transmission instruction, data processing instruction, program control instruction, input F, output instruction and hardware control instruction. 4. The working process of1calculator B and 8 calculator are actually the process of executing instructions quickly. The instruction execution is realized by the hardware of the five-meter computer. When the instruction is executed, it must be loaded into seven memories of the M-meter 1 computer. The CPU is responsible for fetching instructions from five of the seven memories one by one, decoding the instructions into six parts to judge the operation to be completed, and sending control signals to all components to complete the operation, thus completing the execution of L-R instructions starting from seven. When the X instruction is executed and then the next A-L instruction is processed, the CPU repeats the work until the program is completed. There are two kinds of information flow in the process of computer executing instructions: data flow and control flow. Data stream refers to the original data, the result between them, the result data and the source program, etc. These information are read from the 6 memory into the P operator for operation, and the calculation result of 1 is stored in the R memory or transmitted to the output device. Control flow is a control command sent to each component after the controller analyzes and interprets the command, which guides the coordination of each component. B-j?nd-YA R-YA R-YA D-YA D-YA Y-YA L-YA