With these data structures, code modules, and system registers initialized, the processor can be switched to protected mode by loading control register CR0 with a value that sets the PE flag(bit 0).

• 当设置好这些数据结构，代码段以及系统寄存器之后，可以通过设置控制寄存器CR0的PE位(第0位)为1来进入保护模式。