Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
To convert
from an
object of this
Data Type
Field Unit
To an object
of this Data
Type
[See the
Integer and
Buffer Rules]
This action is performed by the AML Interpreter:
If the Field Unit is smaller than or equal to the size of an Integer (in bits), it
will be treated as an Integer. If the Field Unit is larger than the size of an
Integer, it will be treated as a Buffer. The size of an Integer is indicated by
the Definition Block table header’s Revision field. A Revision field value
less than 2 indicates that the size of an Integer is 32 bits. A value greater
than or equal to 2 signifies that the size of an Integer is 64 bits. (See the
conversion rules for the Integer and Buffer data types.)
Integer Buffer If no buffer object exists, a new buffer object is created based on the size of
the integer (4 bytes for 32-bit integers and 8 bytes for 64-bit integers). If a
buffer object already exists, the Integer overwrites the entire Buffer object.
If the integer requires more bits than the size of the Buffer, then the integer
is truncated before being copied to the Buffer. If the integer contains fewer
bits than the size of the buffer, the Integer is zero-extended to fill the entire
buffer.
Buffer Field The Integer overwrites the entire Buffer Field. If the integer is smaller than
the size of the buffer field, it is zero-extended. If the integer is larger than
the size of the buffer field, the upper bits are truncated.
Compatibility Note: This conversion was first introduced in ACPI 2.0. The
behavior in ACPI 1.0 was undefined.
Debug Object The integer is displayed as a hexadecimal value.
Field Unit The Integer overwrites the entire Field Unit. If the integer is smaller than the
size of the buffer field, it is zero-extended. If the integer is larger than the
size of the buffer field, the upper bits are truncated.
String If no string object exists, a new string object is created based on the size of
the integer (8 characters for 32-bit integers and 16 characters for 64-bit
integers). If the string already exists, it is completely overwritten and
truncated or extended to accommodate the converted integer exactly. In
either case, the entire integer is converted to a string of hexadecimal ASCII
characters.
Package Package If no package object exists, a new package object is created. If the package
already exists, it is completely overwritten and truncated or extended to
accommodate the source package exactly. Any and all existing valid (nonnull)
package elements of the target package are deleted, and the entire
contents of the source package are copied into the target package.
Debug Object Each element of the package is displayed based on its type.
796 April, 2015 Version 6.0