出典:Wikipedia
出典:『Wikipedia』 (2011/04/09 08:43 UTC 版)
The IOPL (I/O Privilege level) flag is a flag found on all IA-32 compatible x86 CPUs. It occupies bits 12 and 13 in the FLAGS register. In protected and long mode, it shows the I/O privilege level of the current program or task. The CPL (Current Privilege Level) of the task or program must be less than or equal to the IOPL in order for the task or program to access I/O ports.