Dua| Mode Operation两状态运行cont) Mode bit added to computer hardware to indicate the current mode monitor(o)or user(1 状态位添入计算机硬件,指示正确的状态:管态(0)或用户态(1) e When an interrupt or fault occurs hardware switches to monitor mode 当中断或错误出现,硬件切换至管态 Interrupt/fault monitor user set user mode e Privileged instructions can be issued only in monitor mode. 特权指令只能在管态下使用 Applied Operating System Concepts 2.17Applied Operating System Concepts 2.17 Dual-Mode Operation两状态运行(Cont.) • Mode bit added to computer hardware to indicate the current mode: monitor (0) or user (1). 状态位添入计算机硬件，指示正确的状态：管态（0） 或用户态（1） • When an interrupt or fault occurs hardware switches to monitor mode. • 当中断或错误出现，硬件切换至管态 • Privileged instructions can be issued only in monitor mode. 特权指令只能在管态下使用 monitor user Interrupt/fault set user mode