Advanced Configuration and Power Interface Specification

ACPI Source Language (ASL)Reference
Example
The following example creates the name CNT that references an integer data object with the value 5
and then stores CNT to Local0. After the Store operation, Local0 is an integer object with the value
5.
Name (CNT, 5)
Store (CNT, Local0)
19.6.125 Subtract (Integer Subtract)
Syntax
Subtract (Minuend, Subtrahend, Result) => Integer
Result = Minuend - Subtrahend => Integer
Result -= Subtrahend => Integer
Arguments
Minuend and Subtrahend are evaluated as Integers.
Description
Subtrahend is subtracted from Minuend, and the result is optionally stored into Result. Underflow
conditions are ignored and the result simply loses the most significant bits.
19.6.126 Switch (Select Code To Execute Based On Expression)
Syntax
Switch (Expression) {CaseTermList}
Arguments
Expression is an ASL expression that evaluates to an Integer, String or Buffer.
Description
The Switch, Case and Default statements help simplify the creation of conditional and branching
code. The Switch statement transfers control to a statement within the enclosed body of executable
ASL code
If the Case Value is an Integer, Buffer or String, then control passes to the statement that matches the
value of Switch (Expression). If the Case value is a Package, then control passes if any member of
the package matches the Switch (Value) The Switch CaseTermList can include any number of Case
instances, but no two Case Values (or members of a Value, if Value is a Package) within the same
Switch statement can have the same value.
Execution of the statement body begins at the selected TermList and proceeds until the TermList end
of body or until a Break or Continue statement transfers control out of the body.
The Default statement is executed if no Case Value matches the value of Switch (expression). If the
Default statement is omitted, and no Case match is found, none of the statements in the Switch body
Version 6.0 889