Computer instruction format usually contains two parts: operation code and operand (address code).
Computer instructions are instructions and commands that direct the work of the machine. A program is a series of instructions arranged in a certain order, and the process of executing the program This is the working process of a computer.
The controller relies on instructions to direct the machine to work. People use instructions to express their intentions and give them to the controller for execution. (Recommended learning:web front-end video tutorial)
Principle
The controller relies on instructions to direct the machine to work, and people use instructions to express their intentions. and handed over to the controller for execution. The total set of different instructions that a computer can execute is called the computer's instruction system. Each computer has its own specific instruction system, and its instruction content and format are different.
Content
Usually an instruction includes two aspects: operation code and operand (address code),The operation code determines the operation to be completed, the operation The number refers to the data participating in the operation and the unit address where it is located.
In computers, operation requirements and operand addresses are represented by binary numbers, called operation codes and address codes respectively. The entire instruction is stored in the memory in the form of binary encoding.
The type and number of instructions are related to the specific machine model and will not be described in detail here. Please refer to the specific machine data manual.
Execute the program
The sequential execution of the instructions will complete the execution of the program, so it is necessary to understand the execution process of the instructions. The first is to fetch and analyze instructions. According to the order specified by the program, the currently executed instructions are fetched from the internal memory and sent to the instruction register of the controller. The fetched instructions are analyzed, that is, what operations the computer should perform are determined based on the operation codes in the instructions.
The second is to execute the instructions. According to the instruction analysis results, the controller issues a series of control potentials required to complete the operation in order to direct the relevant components of the computer to complete the operation. At the same time, it is also ready to fetch an instruction.
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