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Acknowledgements

Redistribution and use in source (original document form) and 'compiled' forms (converted to PDF, epub, HTML and other formats) with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code (original document form) must retain the above copyright notice, this list of conditions and the following disclaimer as the first lines of this file unmodified.

2. Redistributions in compiled form (transformed to other DTDs, converted to PDF, epub, HTML and other formats) must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS DOCUMENTATION IS PROVIDED BY TIANOCORE PROJECT "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL TIANOCORE PROJECT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Copyright (c) 2006-2017, Intel Corporation. All rights reserved.

Revision History

Revision	Revision History	Date
1.0	Initial release.	December 2007
1.1	Updated based on errata	August 2008
1.2	Updated based on enhancement requests	June 2009
1.21	Updated based on errata and enhancement requests	March 2010
	Added language filters: RFC_LANGUAGES and ISO_LANGUAGES
	Added Note that a reserved macro name, MDEPKG_NDEBUG
	Definitions in DSC file are now global to both DSC and FDF files
	PCD Values may be constructed using C-style expressions provided the result of the expression matches the datum type of the PCD
	FeatureFlagExpression is now defined as a C-style expression using C relational, equality and logical numeric and bitwise operators and/or arithmetic and bitwise operators that evaluate to a value that matches the Datum Type of the PCD. Precedence and associativity follow C standards
	Spec changed to match existing formats:
	SUPPORTED_ARCHITECTURES and BUILD_TARGETS use the "|" separator, not the comma character
1.22	Errata and grammatical changes	May 2010
1.22 w/	Updates:	December 2011
Errata A	Updated to support UEFI version 2.3.1 and updated spec release dates in Introduction
	Clarify UEFI's PI Distribution Package Specification
	Standardize Common data definitions for all specifications
	Grammatical, formatting and spelling changes
	Replaced "should" with wording saying that it is "recommended"
	Remove "$(WORKSPACE)/" from the examples
	Removed content that only applied to the EDK build system and EDK DSC format that is not used by the EDK II build system
	Rename $(TAGNAME) to $(TOOL_CHAIN_TAG) and remove the synonym $(TOOLCHAIN)
	Added TIME_STAMP_FILE back into the [Defines] section
	Added the SOURCE_OVERRIDE_PATH for EDK components (not valid for EDK II modules)
	Added EDK_GLOBAL as a special type of MACRO statement only valid for EDK INF files
	Added VPD_TOOL_GUID in [Defines] section
	Allow the OUTPUT_DIRECTORY path to be either absolute or relative to the WORKSPACE
	Revised EBNF for PCD sections to allow more precise definitions
	Added EBNF for <Extension>
	Added EBNF for <Keyword> 3.9.x and renamed <LibInstanceMap> to <ClassInstanceMap> in 3.10.
	Require PCDs to use the full name, removing ShortPcdName from definitions
	Updated to clarify that a PCD cannot be used in multiple methods; a PCD can ONLY be used in one way, Also, the <PcdsDyanmic> sub section can only be used if the PCD is not listed in any of the common sections; All instances of the PCD must then use this method
	Revised grammar and include additional clarifications for conditional directives and macro usage; clarify PCD usage in conditional directives and expressions - the $(PcdName) format is never used
	Fixed VPD PCD format; allow the MAX size value to use a wildcard character & added info about where it comes from; added appendix for BPDG file formats; renamed some PCD example tokens and PCD names; cleaned up the sample DSC file
	Removed invalid [|MaximumDatumSize] for HII PCDs in section 2.2.13.3
	Document where VOID* lengths are derived from when not specified in the DSC file
	Clarify that C data arrays must be byte arrays for PCD value fields; both C format and Registry format GUIDs structures are not permitted in VOID* PCD value fields
	Removed the SET statement, used to define values for PCDs from all sections of this document. The SET statement is only valid in FDF files
	Specify how sections are merged during parsing of the EDK II meta-data files	December 2011
	Specifically state how [BuildOptions] content should be applied; define how [BuildOptions] sections are merged
	Clarify where macros are evaluated/expanded
	Provide rules for how macros can be used in different BuildOptions sections
	Clarify Macros in [Defines] section can automatically be used in FDF files.
	Removed references to system environment variables in the Macros section
	Updated conditional rules in 2.2.7 for how to use macro and PCDs; change #elif to #elseif in 3.2.3 to match implementation
	Added the "IN" operator as an Equality Operator - added description and restriction of it's usage using <MemberExpression>
	Corrected [Defines] section information, changed format of for paths, directories and files in common section
	Added table of valid environment variables that can be used in this file
	Make sure that macros are not restricted to directory/path usage - also update EBNF to specifically show MACROVAL - Added <Filename> to macro values.
	Removed unused <VALUE> EBNF from [Defines] section
	Prohibit macros in the filename specified in !include statements; clarify the rules for finding the !include files
	Clarify how macros can be shared between sections
1..22 w/	Updates:	June 2012
Errata B	Section 3.2.1 Fixed the DOS EOL character sequence
	Section 1.2 and 1.3, Updated specs to include current errata versions
	Section 3.2.1 Removed reference to the LineExtension parameter description;1 line entries in the DSC file cannot be extended to multiple lines
	Section 3.2.2 Prohibit macros that replace or define tokens that are defined in this specification, as well as to prohibit <EOL> characters in a macro's value field
	Section 3.4 Revised the value of the BuildNumber to be a NumValUint16, per the PI Specification
	Section 2.8, fix precedence description for obtaining the length of a VOID* PCD: DSC, INF, DEC
	Section 1.3 and 1.4, updated UEFI PI Distribution Package Specification Errata from A to B
	Section 2.2.8,and 3.2.3 Clarify PCD usage in conditional directive statements
	Section 2.3, and 3.4 Clarify location of FDF file
1.22 w/	Updates:	August 2013
Errata C	Sections 1.3 and 1.4 updated UEFI specification versions
	Sections 2.2.8 and 3.2.3 Clarify PCD usage in conditional directive statements
	Sections 2.3 and 3.4, Clarify location of FDF file
	Section 2.8, fixed precedence description for obtaining the length of VOID* PCDs
	Section 3.2.1 Fixed DOS EOL Character Sequence
	Section 3.2.1 Removed reference to the LineExtension parameter description; 1 line entries in the DSC file cannot be extended to multiple lines.
	Section 3.2.1 Require C format for all arrays using curly braces around the byte elements in an array
	Section 3.2.2 Prohibit macros that replace or define tokens that are defined in this specification, as well as to prohibit <EOL> characters in a macro's value field
	Section 3.4, Revised the value of the BUILD_NUMBER to be NumValUint16, per the PI Specification
	Section 3.8 Restrict the size of the HiiOffset to a UINT16
	Appendix D, Added VPD data file examples.
	Various locations, replaced UCS-2 with UCS-2LE
1.24	Updates:	December 2014
	Changed specification from 1.22 Errata C to 1.24.
	Allow specifying the DSC_SPECIFICATION as either 0x00010018 or 1.24.
	Updates specification dates in 1.2 and added new specifications.
	Removed Expression syntax with reference to external document.
	Provide information on how to build multiple instances of a single module.
	Updated the Terms in 1.3.
1.24 w/	Updates:	March 2015
Errata A	Update link to the EDK II Specifications, fixed the name of the Multi-String .UNI File Format Specification
1.25	Updates:	June 2015
	Updated support for UEFI 2.5 and PI 1.4
	Added clarification regarding the use of .. and . in path names in section 2
	In section 2.8.3.7, added clarification regarding allocation of memory based on calculation of maximum size for VOID* PCD entries when the maximum size is not specified in the DSC file
	In section 3.6 added optional <ModuleType> element to the section header in order to support UEFI 2.5 Runtime Drivers that must be 4K page aligned
	Also in 3.6, updated the priority of [BuildOptions] to match current implementation that follows the Build Specification
	In sections 2.3 and 3.5, added new [Defines] boolean entry PCD_VAR_CHECK_GENERATION
	In sections 2.9.3.2, 2.9.3.5, 3.10.4 and 3.10.5 added HII Attribute entry.
	Since the above changes are new features, update the minor revision of the DSC_SPECIFICATION to 0x00010019, older DSC files that do not use the new features do not need to modify the DSC_SPECIFICATION values
	Added clarification on when the DSC_SPECIFICATION value must be updated to 0x00010019
1.26	Specification revision to 1.26	January 2016
	Update the DSC_SPECIFICATION version to 0x0001001A
	Revised WORKSPACE wording for updated build system that can handle packages located outside of the WORKSPACE directory tree (refer to the TianoCore.org/ EDKII website for additional instructions on setting up a development environment).
	Added new system environment variables used by the build system.
1.27	Convert to GitBooks	June 2017
	#351 [DSC Spec] Extend macro usage in the !include statement
	#484 DSC spec: support Prebuild and Postbuild in the [Defines] section
	#353 Build spec: Allow nested includes in DSC and FDF files
	#521 DSC spec: add clarification for mixed PCD usage in the DSC spec
	#519 DSC Spec: update Precedence of PCD Values
	#584 DSC Spec: Update the DSC_SPECIFICATION version to 0x0001001B or 1.27
	#645 DSC Spec: Remove Restriction on Using NULL in [LibraryClasses] Section
	#669 DSC Spec: Add multi-arg support to PREBUILD/POSTBUILD
	#597 DSC Spec: Hii type Pcd VariableName is NOT allowed to be empty string
1.28	Update Version to 1.28	Mar 2018
	Update Skuid value to support Hex number
	Add flexible PCD value format into spec
	Add syntax to support SKU ID inherit from another SKU ID
	Add DefaultStores section to describe the default setting
	Add structure PCD field value assignment syntax
	Add !error statement section
	#1110 Extend exclamation statement's keyword to case-insensitive
1.29	#1453 Update DSC spec to remove EDK related contents	Mar 2019
1.30	#1952 add HOST_APPLIACTION ModuleTpye	July 2019