基于VHDL语言的设计8位CISC微处理器实例

以8位的CISC微控制器为例，说明采用硬件描述语言（HDL）进行数字系统设计的方法．首先采用典型的模块化设计的思想把整个系统分解成数据处理通道和控制通道．数据处理通道主要负责数据处理等，包含所有内部寄存器、算术逻辑单元（ALU）、程序及堆栈指针等．控制通道主要负责系统的控制，其主要的核心部件为一个状态机、状态机根据指令的内容执行不同的控制操作，数据通道在控制通道控制下完成指令的操作内容．采用数据处理和控制独立设计的优点是可以根据他们各自的特点进行相应的设计、文中设计的微处理器可单独使用也可做嵌入式系统．

An Example of 8 Bits CISC Microcontroller Design Using VHDL

The design of 8 bits microcontroller is taken as an example of methodology of digital system design using HDL. At first, the whole system is divided into two parts by the concept of the modulation design. The two parts are the data path unit and the control unit. The data path unit processes data conjsisting registers, ALU, program, stack pointer and so on. The control unit takes over the whole system. Its core component is a SM （State Machine）. The SM executes operations according to the content of instructions and controls the data path unit. The scheme considering the two parts separately is that they can be designed according their characters. The microcontroller designed in this paper can be used independently or as an embedded system.