上一讲我们介绍了一位机的系统结构和各主要芯片,这一讲介绍一位机基本指令系统。所谓“指令”,就是指示微处理器执行某种操作的“命令”。对一个具体的微处理器来说,它能接受和执行的指令种类和数目是有限的,少则十几条,多则百余条,有的16位机甚至可达千余条。一个微处理器可以接受和执行的指令的总和就叫作它的“指令系统”。不同的微处理器具有不同的指令系统。一般说,指令系统中包含的指令愈多,则微处理器的功能愈强,编 Last talk we introduced a machine’s system architecture and the main chip, this talk introduces a machine basic instruction system. The so-called “instructions”, is to instruct the microprocessor to perform some kind of “command”. For a specific microprocessor, it can accept and implement the type and number of instructions is limited, ranging from as few as ten, as many as more than 100, and some 16-bit machine even up to more than a thousand. The sum of instructions that a microprocessor accepts and executes is called its “instruction set.” Different microprocessors have different instruction systems. In general, the more instructions contained in the instruction system, the stronger the function of the microprocessor, compiled