What Is an Instruction Set?
Computer instructions are instructions and commands that instruct the machine to work. A program is a series of instructions arranged in a certain order. The process of executing a program is the working process of a computer. The instruction set is a set of instructions used by the CPU to calculate and control the computer system, and each new type of CPU specifies a series of instruction systems that cooperate with other hardware circuits during design. Whether the instruction set is advanced or not is also related to the performance of the CPU. It is also an important indicator of the performance of the CPU. Each CPU is specified in the design of a series of instruction systems to cooperate with its hardware circuit. The strength of the instruction is also an important indicator of the CPU. The instruction set is one of the most effective tools to improve the efficiency of the microprocessor. In terms of the current mainstream architecture, the instruction set can be divided into two parts: a complex instruction set and a reduced instruction set [1] .
- In a computer, a command that instructs the computer hardware to perform certain operations and processing functions is called an instruction. Instructions are the smallest functional unit in which a computer operates, and the role of hardware is to complete the functions specified by each instruction. The collection of all instructions on a computer is the computer's instruction system. The instruction system, also called instruction set, is the embodiment of all the functions of this computer. The first thing people consider when designing a computer is the functions it has, that is, firstly design the instruction set according to the function level, and then implement it in hardware according to the requirements of the instruction set. The instruction system is not only a collection of instructions, but also includes the instruction format, addressing mode, and data form of all instructions. Therefore, the instruction system executed by each computer not only determines the capabilities required by the machine, but also determines the format of the instructions and the structure of the machine. Conversely, machines with different structures and different instruction formats should have instruction systems that match them. For this reason, when designing the instruction system, due attention should be paid to the instruction format, type, and operation function. Software is a program of various systems and users written for the use of a computer. A program consists of a sequence of computer instructions. From this perspective, instructions are a computer language unit used to design programs [2]
- The AT command set was invented by Hayes, which was originally a company that produced dial-up modems. The original purpose of the AT command set was to control dial-up modems. The control protocol was in text format and each command Starting with AT, the AT instruction set got its name. With the continuous advancement of technology, low-speed dial-up modems have gradually started to fail to meet the requirements of high-bandwidth and high-speed applications, so they have gradually been eliminated by the market. Hayes also disappeared in this wave of technological upgrading. However, the AT command was preserved. Since then, several major mobile phone manufacturers, Nokia, Motorola, HP, and Ericsson have been extended based on the Hess AT command to develop a complete set of GSM module control in mobile phones. AT command. As a result, the GSM 07.05 standard and the GSM07.07 standard later include AT commands. And the industrial common PDU, GPRS control, etc. also use AT commands for actual control. Therefore, the AT directive has also become the de facto standard for these products. ATCoP is an abbreviation of AT Command Processor. It is a module responsible for software to implement AT commands. We add and modify AT commands through AT command processors. The specific process is: when the AT command processor receives the AT command from the serial port, performs the corresponding parsing work, and searches the AT command table to find whether there is a corresponding processing option according to the specific analysis result. If a corresponding item is found, it continues to execute corresponding
- The implementation architecture of the AT command processor is shown in the figure
- The main work of the SIO data preprocessing module is to perform a data preprocessing on the AT commands received by the serial port, and at the same time, send the non-terminated command line generated by the preprocessing to the AT command parsing module.
- The AT command parsing module parses the transmitted non-terminated command line, maps each non-interrupted command line to a token structure, and puts the token structure into a queue to form an AT command table. Wait for the AT command processing module to make a search call.
- When the AT command processing module processes the AT command, it searches the token structure in the AT command table one by one. If a matching option is found, it continues to execute the specific processing function and deletes the token structure. The AT command response generation module mainly formats and parses the response data generated by the AT command, and transmits the formatted response to the data terminal equipment (Data Terminal Equipment).
- The fault tolerance mechanism of the AT command processor is: only one AT command is processed at a time, and if there is an error in the AT command, the SIO data preprocessing module will give an error response and generate an error code, which will not be processed deal with.
- The conventional satellite mobile communication system is mainly composed of satellite, satellite antenna, power amplifier and radio frequency module, channel module and user. Among them, the ground station network control center (NCC) is responsible for the unified management and control of the satellite ground station equipment in the entire satellite network to enter and exit the network, the establishment of satellite business channels, and various business processes. Satellite ground station equipment includes satellite control channels, satellite service channels, radio frequency and power amplifier equipment, and satellite transceiver antennas. It is responsible for the business process control, service data collection, modulation and demodulation of the entire satellite service. The satellite control channel is mainly responsible for the transmission control of control signaling such as network access and network exit for the entire satellite ground station equipment. The satellite service channel is responsible for encrypting, modulating and demodulating the satellite service data or satellite voice data to be transmitted to the radio frequency. Equipment, or modulate, decode, and decrypt the received RF signals into satellite service data or voice data. The radio frequency equipment and the satellite transceiver antenna are mainly responsible for transmitting or receiving satellite radio frequency signals transmitted from the opposite end through the channel processed satellite data. When the satellite user 1 of the satellite ground station device 1 wants to perform satellite communication with the user N of the satellite ground station device N, the user 1 initiates a satellite service through a satellite telephone terminal or a satellite data terminal. At this time, the satellite control channel will initiate the service The control signaling is processed, and the air link service channel is established for the two satellite ground station devices through the ground station network management control center, and then the users of the two ground stations can perform the required service communication. When the communication is over, one user hangs up, and the satellite control terminal will initiate service end control signaling to remove the satellite link between the two satellite ground station equipment. Through the previous introduction, we can know that during the entire satellite mobile communication process, due to the inherent delays and other characteristics of satellite communications, normal satellite service communications must be performed, and the network access control, voice or satellite data of each satellite ground station equipment The initiation and end of the process, the establishment and removal of satellite service links, and other control processes play a vital role, so here we introduce the simple and reliable AT instruction set as a control protocol for satellite mobile communication systems. Here we refer to the satellite control channel as the AT Command Processor (AP Command Processor) and the satellite service channel as the Channel Processor (CP). In the satellite control channel, the AT command is used to specifically target the ground. Control and analysis of station equipment, initiation and management of satellite business processes, and setting and querying of CP. The CP mainly receives the setting and query commands of some parameters from the AP, and the specific process of business communication according to the AT instruction from the AP [4] .