Advanced Configuration and Power Interface Specification

ACPI Source Language (ASL)Reference
Description
The WordBusNumber macro evaluates to a buffer which contains a 16-bit bus-number resource
descriptor. The format of the 16-bit bus number resource descriptor can be found in “Word Address
Space Descriptor ” (page 360). The macro is designed to be used inside of a ResourceTemplate
(page 882).
19.6.145 WordIO (Word IO Resource Descriptor Macro)
Syntax
WordIO (ResourceUsage, IsMinFixed, IsMaxFixed, Decode, ISARanges, AddressGranularity,
AddressMinimum, AddressMaximum, AddressTranslation, RangeLength, ResourceSourceIndex,
ResourceSource, DescriptorName, TranslationType, TranslationDensity)
Arguments
ResourceUsage specifies whether the I/O range is consumed by this device (ResourceConsumer)
or passed on to child devices (ResourceProducer). If nothing is specified, then ResourceConsumer
is assumed.
IsMinFixed specifies whether the minimum address of this I/O range is fixed (MinFixed) or can be
changed (MinNotFixed). If nothing is specified, then MinNotFixed is assumed. The 1-bit field
DescriptorName. _MIF is automatically created to refer to this portion of the resource descriptor,
where ‘1’ is MinFixed and ‘0’ is MinNotFixed.
IsMaxFixed specifies whether the maximum address of this I/O range is fixed (MaxFixed) or can be
changed (MaxNotFixed). If nothing is specified, then MaxNotFixed is assumed. The 1-bit field
DescriptorName. _MAF is automatically created to refer to this portion of the resource descriptor,
where ‘1’ is MaxFixed and ‘0’ is MaxNotFixed.
Decode specifies whether or not the device decodes the I/O range using positive (PosDecode) or
subtractive (SubDecode) decode. If nothing is specified, then PosDecode is assumed. The 1-bit field
DescriptorName. _DEC is automatically created to refer to this portion of the resource descriptor,
where ‘1’ is SubDecode and ‘0’ is PosDecode.
ISARanges specifies whether the I/O ranges specifies are limited to valid ISA I/O ranges (ISAOnly),
valid non-ISA I/O ranges (NonISAOnly) or encompass the whole range without limitation
(EntireRange). The 2-bit field DescriptorName._RNG is automatically created to refer to this
portion of the resource descriptor, where ‘1’ is NonISAOnly, ‘2’ is ISAOnly and ‘0’ is EntireRange.
AddressGranularity evaluates to a 16-bit integer that specifies the power-of-two boundary (- 1) on
which the I/O range must be aligned. The 16-bit field DescriptorName. _GRA is automatically
created to refer to this portion of the resource descriptor.
AddressMinimum evaluates to a 16-bit integer that specifies the lowest possible base address of the I/
O range. The value must have ‘0’ in all bits where the corresponding bit in AddressGranularity is
‘1’. For bridge devices which translate addresses, this is the address on the secondary bus. The 16-bit
field DescriptorName._MIN is automatically created to refer to this portion of the resource
descriptor.
AddressMaximum evaluates to a 16-bit integer that specifies the highest possible base address of the
I/O range. The value must have ‘0’ in all bits where the corresponding bit in AddressGranularity is
‘1’. For bridge devices which translate addresses, this is the address on the secondary bus. The 16-bit
Version 6.0 903