After spending forty hours in three days of trying, I finally copied some source code out of the IBM Technical Reference Manual, and I was able to enter protected mode and then return to DOS.

• 在3天里，进行了40个小时的尝试之后，我终于可以在模仿IBM技术参考手册里的一些源代码的情况下，自由的进入保护模式并且返回DOS。