3.4.1 Modes of Execution(1/ 1) User mode Less-privileged mode User programs typically execute in this mode System mode, control mode, or kernel mode More-privileged mode Kernel of the operating system Translation between the two model Processor status register(psr) and current privileged level(cpl User mode-> System mode System mode->User mode3.4.1 Modes of Execution(1/1) • User mode • Less-privileged mode • User programs typically execute in this mode • System mode, control mode, or kernel mode • More-privileged mode • Kernel of the operating system • Translation between the two model • Processor status register (psr) and current privileged level (cpl) • User mode->System mode • System mode->User mode 4