Use this system macro to:
- Disable input/output (I/O) interrupts and lock a resource
- Unlock a resource and enable I/O interrupts.
Required Authorizations
|
Key0
| Restricted
| System
| Common Storage
|
| X
| X
|
|
Format
- label
- An optional label can be used with this macro.
- LKWORD=(reg)
- A register containing the address of a doubleword lock field. R0
through R7 are valid registers. This parameter is required.
- FUNC
- Specify one of the following:
- LOCK
- The lockword specified by the LKWORD parameter will be locked and I/O
interrupts will be disabled on the I-stream issuing this macro.
- UNLOCK
- The lockword specified by the LKWORD parameter will be unlocked and I/O
interrupts will be enabled on the I-stream issuing this macro.
Entry Requirements
- This macro should only be issued by ECB-controlled programs.
- The register referred to by the LKWORD parameter must contain the address
of a valid lockword name.
Return Conditions
- Control is returned to the next sequential instruction.
- Registers R0 through R7 are saved. The contents of other registers
cannot be predicted.
Programming Considerations
This macro can only be used by ECB-controlled programs.
Examples
- To disable I/O interrupts and lock the SSST in memory:
LA R2,SSTHLCK
DLCKC LKWORD=(R2),FUNC=LOCK
This causes I/O interrupts on this I-stream to be disabled and the SSST to
be locked. R2 points to the SSST lock (SSTHLCK).
- To enable I/O interrupts and unlock the SSST in memory:
LA R5,SSTHLCK
DLCKC LKWORD=(R5),FUNC=UNLOCK