说明：  介绍vhdl硬件描述语言的特点及设计思想，运用vhdl硬件描述语言实现计算机原理实验中RAM存储器的设计方法，重点描述了对传统计算机组成原理实验中移植到基于CPLD平台的思想
(introduced vhdl hardware description language features and design ideas, vhdl use hardware description language computer science experiments RAM memory design, Description of key computer components of the traditional principle experiment to transplant platform based on the idea of CPLD)