General CPU Experiment System Design And Implementation

Teaching experiment computer is a essential tool in computer organization course,it provides the hardware and software platform for experiment. With the up-to-date computer and microelectronics technology innovation, CPU design has been a hot research topic in recent years. At present, all kinds of experiment tools such as TEC-2000 and XS40 are all limited to instruction set, instruction format, data expression, addressing mode and storage mode. Student only could make CPU implementation and verification, or design function unit under the determinate computer architecture. Therefore, traditional experiment tools are not flexible and couldn't meet the computer self-design requirement. The reason for such limitation is that the monitor and test program must run in the same CPU, namely it is a binary compatible problem. In this paper, we provide a new thought to build a general CPU experiment platform for research and design purpose. In this platform, experimenter could be free to design their own CPU from instruction set, instruction format, data expression, addressing mode and storage mode, it also could debug and verify all kinds of 16 bit CPU with different architecture. The whole platform is divided into two parts, CPU core and mainboard that provide core's running environment. Firstly, we design a reference CPU, and then design the mainborad to provide the debug and test environment for it. The reference CPU core use VHDL language input, make logic synthesis and simulation through the popular EDA tools, then it was implemented in FPGA. As long as experimenter provide the description of instruction set, this platform could generate the assembly code for making test and verification. Therefore, experimenter could be free to design their own CPU without any limitation, such as instruction set, data path, control path .General CPU platform provide the great flexibility. Experimenter could design CPU at the beginning without limitation of the computer architecture and hardware. Experimenter also could study the popular design tools and method , as well as understand computer organization in depth. It achieved a good result. This system not only plays a positive role in computer organization experiment, but also provides a open platform for different CPU architecture design and research purpose.