设计一个字节（8 位）比较器。

要求：比较两个字节的大小，如a[7:0]大于 b[7:0]输出高电平,否则输出低电平,改写测试

模型,使其能进行比较全面的测试 。

-design a byte (8) for comparison. Requirements : To compare the size of two bytes, as a greater than [7:0] b [7:0] output margin. Otherwise, low-level output, rewritten test model, in order to enable them to conduct more comprehensive tests.