Each time a segment selector is loaded on to segment registers, the corresponding segment descriptor is loaded from memory into a matching non-programmable CPUregister.
每次将段选择器加载到段寄存器中时，对应的段描述符都会从内存加载到相匹配的不可编程CPU寄存器中。
2
In order to know this, the CPU must be continually 'polling' the interface (reading the status register), and finally latched the data.
为了得知外设是否就绪，CPU必须不停地轮询接口(读状态寄存器)并最终锁存数据。
3
The CPU reads the register and calculates residence and latency times that is entered in PTP follow up packets.