add code comment.

tb/shinTest/ShinTopBareTb.v

@@ -340,10 +340,12 @@ initial begin
 	$stop;
 end
 
+//生成高倍率的时钟
 initial begin
 	forever begin #10 clk8x <= ~clk8x; end
 end
 
+//生成主时钟
 initial begin
 	forever begin #80 clock <= ~clock; end
 end