What is meant by a privileged instruction How does it apply

What is meant by a \" privileged\" instruction? How does it apply to operating systems?

Solution

1)it is type of instruction which contains protection settings,interrupt handlers,i/o, process status instruction

and this instruction is executed only when system is in supervised mode or priviliged mode which is in operating
system

2)in os there are two modes user mode and previliged mode all preveliged instruction run in this mode

1)these instruction are used in memory address mapping and flush the cache data
2)it also read and load system registers
3)changing the modes in operating system
4)it also perform some i/o operations