Q.2. Prerequisite Specifications¶
In general, this specification requires that functionality defined in a number of other existing specifications be present on a system that implements this specification. This specification requires that those specifications be implemented at least to the extent that all the required elements are present.
This specification prescribes the use and extension of previously established industry specification tables whenever possible. The trend to remove runtime call-based interfaces is well documented. The ACPI (Advanced Configuration and Power Interface) specification is an example of new and innovative firmware technologies that were designed on the premise that OS developers prefer to minimize runtime calls into firmware. ACPI focuses on no runtime calls to the BIOS.
Q.2.1. ACPI Specification¶
The interface defined by the Advanced Configuration and Power Interface (ACPI) Specification is the primary OS runtime interface for IA-32, x64 and Itanium platforms. ACPI fully defines the methodology that allows the OS to discover and configure all platform resources. ACPI allows the description of non-Plug and Play motherboard devices in a plug and play manner. ACPI also is capable of describing power management and hot plug events to the OS. (For more information on ACPI, see “Links to UEFI-Related Documents” (http://uefi.org/uefi ) under the heading “ACPI”; see also http://uefi.org/acpi ).
Q.2.2. Additional Considerations for Itanium-BasedPlatforms¶
Any information or service that is available in Itanium architecture firmware specifications supercedes any requirement in the common supported 32-bit and Itanium architecture specifications listed above. The Itanium architecture firmware specifications (currently the Itanium® System Abstraction Layer Specification and portions of the Intel® Itanium® Architecture Software Developer’s Manual, volumes 1-3) define the baseline functionality required for all Itanium architecture platforms. The major addition that UEFI makes to these Itanium architecture firmware specifications is that it defines a boot infrastructure and a set of services that constitute a common platform definition for high-volume Itanium architecture-based systems to implement based on the more generalized Itanium architecture firmware specifications.
The following specifications are the required Intel Itanium architecture specifications for all Itanium architecture-based platforms:
“Itanium® System Abstraction Layer Specification” heading at “Links to UEFI-Related Documents” (http://uefi.org/uefi) .
“Itanium® Architecture Software Developer’s Manual, Volume 1: Application Architecture, Rev. 2.2,” heading at “Links to UEFI-Related Documents” (http://uefi.org/uefi) .
“Itanium® Architecture Software Developer’s Manual, Volume 2: System Architecture, Rev. 2.2” heading at “Links to UEFI-Related Documents” (http://uefi.org/uefi) .
“Itanium® Architecture Software Developer’s Manual, Volume 3: Instruction Set Reference, Rev. 2.2” heading at “Links to UEFI-Related Documents” (http://uefi.org/uefi) .