Use this system macro to allow an operational program to change the
operating state of the central processing unit (CPU) from problem state to
supervisor state. Supervisor state allows processing of privileged
instructions such as set system mask (SSM) and start input/output
(SIO).
Format
- label
- A symbolic name can be assigned to the macro statement.
Entry Requirements
- R9 must contain the address of the ECB being processed.
- Only use this macro with utility-type programs such as disk copy and tape
reel switch that have special requirements for supervisor state.
Return Conditions
- Control is returned to the next sequential instruction (NSI).
- The contents of R14 and R15 are unknown.
- The contents of all other registers are preserved across this macro
call.
- The CPU is in supervisor state (PSW bit 15 = 0).
- The storage protect key is zero (PSW bits 8 through 11).
Programming Considerations
- This macro can be run on any I-stream.
- Use caution when operating in this state. Any location in storage
can be modified by the operational program. A program should operate in
this state for the shortest possible time and then issue a LMONC macro to
return to problem state.
- Supervisor state is maintained across all other macros, which can be
issued by the program.
Examples
None.