Advanced Configuration and Power Interface Specification

ACPI Source Language (ASL)Reference
19.6.85 Multiply (Integer Multiply)
Syntax
Multiply (Multiplicand, Multiplier, Result) => Integer
Result = Multiplicand * Multiplier => Integer
Result *= Multiplier => Integer
Arguments
Multiplicand and Multiplier are evaluated as Integers.
Description
The Multiplicand is multiplied by Multiplier and the result is optionally stored into Result. Overflow
conditions are ignored and results are undefined.
19.6.86 Mutex (Declare Synchronization/Mutex Object)
Syntax
Mutex (MutexName, SyncLevel)
Arguments
Creates a data mutex synchronization object named MutexName, with a synchronization level from
0 to 15 as specified by the Integer SyncLevel.
Description
A synchronization object provides a control method with a mechanism for waiting for certain events.
To prevent deadlocks, wherever more than one synchronization object must be owned, the
synchronization objects must always be released in the order opposite the order in which they were
acquired.
The SyncLevel parameter declares the logical nesting level of the synchronization object. The
current sync level is maintained internally for a thread, and represents the greatest SyncLevel among
mutex objects that are currently acquired by the thread. The SyncLevel of a thread before acquiring
any mutexes is zero. The SyncLevel of the Global Lock (\_GL) is zero.
All Acquire terms must refer to a synchronization object with a SyncLevel that is equal or greater
than the current level, and all Release terms must refer to a synchronization object with a SyncLevel
that is equal to the current level.
Mutex synchronization provides the means for mutually exclusive ownership. Ownership is acquired
using an Acquire term and is released using a Release term. Ownership of a Mutex must be
relinquished before completion of any invocation. For example, the top-level control method cannot
exit while still holding ownership of a Mutex. Acquiring ownership of a Mutex can be nested (can be
acquired multiple times by the same thread).
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