C6678外接4片ddr3，阅读sprabi1b文档，存在疑问如下：
（1） p21写有如下片段
Each trace to the respective within 500 mils and the opposite side of the termination£termination should be resistor should tie directly to the VTT rail.
疑问：上面写的500mils是指ddr3到另外一片ddr3的地址、控制信号走线长度不超过500mils么？
（2）p27写有如下片段
Address and command fly-by groups must have stubs less than 80 mils and be length-matched within +/- 10 mils.
疑问：请问80mil是指下图的哪段线的长度？
