用vhdl的4x4的数据选择器，在maxplusII下编译、仿真通过。是构成大型数字电路的重要部件。适合vhdl初学者分析学习。-4x4 with the VHDL data selectors, under the maxplusII compiler, simulation through. Yes constitute large-scale digital circuits important components. VHDL Analysis for beginners to lear