gtps1m3l | System Macros |
Use this system macro to set the low address protect hardware feature. This feature protects the first 512 bytes of storage against alteration by a program regardless of the storage key used by the program.
Format
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It is assumed that a call to LCPCC to turn off the low address protection bit is issued with the same save area as that used by a call to LCPCC to obtain status for the low address protect bit.
It is assumed that an LCPCC call was issued turning off the low address protection bit, using the same save area as the LCPCC call that obtained the low address protect status.
The low address protect bit is retrieved from CR0SAVE and loaded into control register 0. The other bits in the control register are unchanged. If other bits were modified in control register 0 between when LCPCC PROTECT=OFF was issued and when LCPCC PROTECT=RESTORE was issued, these bits are not be affected by this macro.
Entry Requirements
E-type programs must be in supervisor state to run this macro. This requires a MONTC call and authorization to use it through correct program allocation.
Return Conditions
None.
Programming Considerations
Examples
* TURN LOW CORE PROTECTION OFF LCPCC PROTECT=OFF,CR0SAVE=EBW000
* RESTORE LOW CORE PROTECTION LCPCC PROTECT=RESTORE,CR0SAVE=EBW000
* TURN LOW CORE PROTECTION ON LCPCC PROTECT=ON,CR0SAVE=EBW000