The instructions that computer hardware can recognize and directly execute are machine instructions. Machine instructions are instructions that the CPU can directly recognize and execute. They usually consist of two parts: an opcode and an operand. The opcode points out the operation to be completed by the instruction, that is, the function of the instruction. The operand points out the objects participating in the operation and the results of the operation. Storage location, etc.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
The instructions that computer hardware can recognize and directly execute are machine instructions.
Machine Instructions (Machine Instructions) are instructions that the CPU can directly recognize and execute. Its expression is binary encoding. Machine instructions usually consist of two parts: an operation code and an operand. The operation code indicates the operation to be completed by the instruction, that is, the function of the instruction. The operand indicates the objects participating in the operation and the location where the operation results are stored.
Since machine instructions are closely related to the CPU, different types of CPUs correspond to different machine instructions, and their instruction systems are often very different. But for CPUs of the same series, in order to achieve good compatibility between various models, it must be achieved: the instruction system of the new generation CPU must include the instruction system of the previous CPU of the same series. Only in this way can various previously developed programs run normally on the new generation of CPUs.
Machine language is used to directly describe machine instructions, rules for using machine instructions, etc. It is the only language that the CPU can directly recognize, that is, the CPU can directly execute programs described in machine language.
Writing programs in machine language was the job of professional and technical personnel who had undergone rigorous training in the early days. Ordinary programmers are generally not competent. Moreover, programs written in machine language are not easy to read, have a high error rate, are difficult to maintain, and cannot Intuitively reflect the basic ideas of using computers to solve problems.
#Due to the above inconveniences in writing programs in machine language, almost no programmers write programs in this way.
Extended knowledge: the relationship between machine instructions and microinstructions
1. Different concepts
1. Machine instructions: Machine instructions are things that the CPU can directly identify and instructions to execute.
2. Microinstructions: refers to a combination of a set of microcommands that implement certain operating functions in one CPU cycle of the machine, and statements describing microoperations.
2. Different expression formats
1. Machine instructions: The expression form is binary encoding.
2. Microinstructions: The format is divided into horizontal microinstructions and vertical microinstructions.
3. Different principles
1. Machine instruction: Machine instruction usually consists of two parts: operation code and operand. The operation code indicates the operation to be completed by the instruction, that is, the function of the instruction, and the operation The number indicates the objects involved in the operation and the location where the operation results are stored.
2. Microinstructions: The function of a machine instruction is realized by a sequence of several microinstructions, that is, the operation completed by a machine instruction is divided into several microinstructions to complete, and the microinstructions interpret and Execution, this sequence of microinstructions is often called a microprogram.
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