8位流水灯程序设计，跑马灯效果显示，里面是VHDL程序。-8 water lamps program design, which is a VHDL program

用VHDL语言设计实现一个彩灯控制（8个发光二极管）电路，仿真并下载验证其功能。彩灯有两种工作模式，可通过拨码开关或按键进行切换。 ? 单点移动模式：一个点在8个发光二极管上来回的亮。 ? 幕布式：从中间两个点，同时向两边依次点亮直至全亮， 然后再向中间点灭，依次往复。 -VHDL Language Design and Implementation with a lantern control (8 LEDs) circuit, simulation and download v

Write VHDL codes to show, on two 7-segment LEDs, the binary coded decimal (BCD) equivalence of the binary representation of the state of eight switches. Use a function to perform the specified task. Assume that the 7-segment LEDs are turned on with l