An instruction that may be executed in supervisor or master modes but not in the application or I / O modes .
u4e00u79cdu53efu4ee5u5728 u7ba1 u6001u6216u4e3bu6001u4e0bu6267u884cuff0cu4f46u4e0du80fdu5728 u76ee u6001u6216 u8f93u5165 u8f93u51fau72b6u6001u4e0bu6267u884cu7684u6307u4ee4u3002
[计] 管理程序输入输出