Control instructions include all privileged and semiprivileged machine instructions, except the input/output instructions described in Input/output operations.

Privileged instructions are processed only when the processor is in the supervisor state. An attempt to process an installed privileged instruction in the problem state generates a privileged-operation exception.

Semiprivileged instructions are those instructions that can be processed in the problem state when certain authority requirements are met. An attempt to process an installed semiprivileged instruction in the problem state when the authority requirements are not met generates a privileged-operation exception or some other program-interruption condition depending on the particular requirement that is violated.

For further details, see "Control Instructions" in the z/Architecture Principles of Operation information.