All registers included in this partition are dedicated to the USB Root Hub which is an integral part of the Host Controller though still a functionally separate entity. The HCD emulates USBD accesses to the Root Hub via a register interface. The HCD maintains many USB-defined hub features which are not required to be supported in hardware. For example, the Hub’s Device, Configuration, Interface, and Endpoint Descriptors are maintained only in the HCD as well as some static fields of the Class Descriptor. The HCD also maintains and decodes the Root Hub’s device address as well as other trivial operations which are better suited to software than hardware.

上文:
本分区包含的所有寄存器均专用于USB根集线器（Root Hub）——该器件虽是主机控制器的集成部件，但仍为功能独立的实体。主机控制器驱动程序（HCD）通过寄存器接口模拟USBD对根集线器的访问。HCD维护了许多USB定义的集线器特性，这些特性无需硬件支持。例如：集线器的设备描述符、配置描述符、接口描述符和端点描述符仅由HCD维护，类别描述符的某些静态字段亦同。HCD还维护并解码根集线器的设备地址，以及其他更适合软件处理而非硬件实现的简易操作。

The Root Hub register interface is otherwise developed to maintain similarity of bit organization and operation to typical hubs which are found in the system. Below are four register definitions: HcRhDescriptorA, HcRhDescriptorB, HcRhStatus, and HcRhPortStatus[1:NDP]. Each register is read and written as a Dword. These registers are only written during initialization to correspond with the system implementation. The HcRhDescriptorA and HcRhDescriptorB registers should be implemented such that they are writeable regardless of the HC USB state. HcRhStatus and HcRhPortStatus must be writeable during the USBOPERATIONAL state.

上文:
根集线器寄存器接口的设计保持了与系统中典型集线器在比特位组织和操作上的相似性。以下为四个寄存器定义：HcRhDescriptorA、HcRhDescriptorB、HcRhStatus和HcRhPortStatus[1:NDP]。每个寄存器均以双字（Dword）为单位进行读写操作。这些寄存器仅在初始化阶段根据系统实现进行写入。HcRhDescriptorA和HcRhDescriptorB寄存器应实现为可写状态（无论HC处于何种USB状态）。HcRhStatus和HcRhPortStatus必须在USBOPERATIONAL状态下保持可写。

Note: IS denotes an implementation-specific reset value for that field.

注：IS表示该字段的复位值为实现特定值。