Specifications

System Macros Invoked by Drivers

DSBINT

Blocks interrupts from occurring on the local processor at or below a speciﬁed

IPL.

Format

DSBINT [ipl=31] [,dst=–(SP)] [,environ=MULTIPROCESSOR]

Parameters

[ipl=31]

IPL at which to block interrupts. If no ipl is speciﬁed, the default is IPL 31,

which blocks all interrupts.

[dst=–(SP)]

Location in which to save the current IPL. If no destination is speciﬁed, the

current IPL is pushed onto the stack.

[environ=MULTIPROCESSOR]

Processing environment in which the DSBINT synchronization macro

is to be assembled. If you do not specify environ, or if you do specify

environ=MULTIPROCESSOR, the DSBINT macro generates the following

assembly-time warning message, where xx is an IPL above IPL 2:

%MACRO-W-GENWARN, Generated WARNING: Raising IPL to #xx provides no multiprocessing synchronization

If you are certain that the purpose of the macro invocation is to block only

local processor events, you can disable the warning message by including

environ=UNIPROCESSOR in the invocation.

Description

The DSBINT macro ﬁrst stores the current IPL of the local processor and then

moves the speciﬁed IPL into the processor’s IPL register (PR$_IPL).

Note that the DSBINT and ENBINT macros provide full synchronization only

in a uniprocessing environment. In a multiprocessor conﬁguration, DSBINT

and ENBINT are suitable only for blocking events on the local processor. To

provide synchronized access to system resources and devices in a multiprocessing

environment, you must use the DEVICELOCK/DEVICEUNLOCK, FORKLOCK

/FORKUNLOCK, and LOCK/UNLOCK macros.

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