Use this system macro 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). Use of this macro
is restricted to utility type programs (such as disk copy and tape switch)
that have special requirements for this state (system programming use
only).
Required Authorizations
|
Key0
| Restricted
| System
| Common Storage
|
| X
| X
|
|
Format
- label
- A symbolic name can be assigned to the macro statement.
Entry Requirements
R9 must contain the address of the ECB being processed.
Return Conditions
- Control is returned to the next sequential instruction (NSI).
- The contents of R14 and R15 are unknown.
- The contents of registers R0 through R7 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.
- Care should be exercised when operating in this state. Any area
above the 512-byte line can be modified in low main storage with just a
MONTC. If low main storage below the 512-byte line is to be modified,
the LCPCC macro with low memory protection disabled must be issued
first. Afterward LCPCC must be issued to re-enable low memory
protection.
- 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.
- Registers R10 and R13 must be saved and restored if required by the
calling program.
Examples
None.