Specifications

System Macros Invoked by Drivers

LOCK_SYSTEM_PAGES

• If it speciﬁed the ipl argument to the LOCK_SYSTEM_PAGES macro, the

code segment must restore the previous IPL, either explicitly, through the use

of the ipl argument to the UNLOCK_SYSTEM_PAGES macro, or through the

use of one of the system synchronization macros.

Example

TSTB (R0) ; Fault in page

30$: LOCK_SYSTEM_PAGES,-

END=100$ ; Lock down pages

LOCK LOCKNAME=MMG,- ; Synch with MMG

SAVIPL=-(SP) ; Save current IPL

MOVL W^MMG$GL_SYSPHD,R3 ; Get system PHD

UNLOCK LOCKNAME=MMG,- ; Unlock MMG

NEWIPL=(SP)+ ; Restore IPL

UNLOCK_SYSTEM_PAGES ; Unlock pages

100$:

In this example, the LOCK_SYSTEM_PAGES macro locks all pages between

labels 30$ and 100$ into the system working set. The UNLOCK_SYSTEM_

PAGES macro does the coroutine return to unlock those pages locked by the

LOCK_SYSTEM_PAGES macro call.

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