Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Arguments
IndexName and DataName refer to field unit objects. AccessType, LockRule, UpdateRule, and
FieldList are the same format as the Field term.
Description
Creates a series of named data objects whose data values are fields within a larger object accessed by
an index/data-style reference to IndexName and DataName.
This encoding is used to define named data objects whose data values are fields within an index/data
register pair. This provides a simple way to declare register variables that occur behind a typical
index and data register pair.
Accessing the contents of an indexed field data object will automatically occur through the
DataName object by using an IndexName object aligned on an AccessType boundary, with
synchronization occurring on the operation region that contains the index data variable, and on the
Global Lock if specified by LockRule.
The value written to the IndexName register is defined to be a byte offset that is aligned on an
AccessType boundary. For example, if AccessType is DWordAcc, valid index values are 0, 4, 8, etc.
This value is always a byte offset and is independent of the width or access type of the DataName
register.
Example
The following is a block of ASL sample code using IndexField:
Creates an index/data register in system I/O space made up of 8-bit registers.
• Creates a FET0 field within the indexed range.
Method (EX1) {
// Define a 256-byte operational region in SystemIO space
// and name it GIO0
OperationRegion (GIO0, 1, 0x125, 0x100)
// Create a field named Preserve structured as a sequence
// of index and data bytes
Field (GIO0, ByteAcc, NoLock, WriteAsZeros) {
IDX0, 8,
DAT0, 8,
.
.
.
}
// Create an IndexField within IDX0 & DAT0 which has
// FETs in the first two bits of indexed offset 0,
// and another 2 FETs in the high bit on indexed
// 2F and the low bit of indexed offset 30
850 April, 2015 Version 6.0