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EFI System Table
Version 1.10 12/01/02 4-3
4.2 EFI Table Header
The data type EFI_TABLE_HEADER is the data structure that precedes all of the standard EFI
table types. It includes a signature that is unique for each table type, a revision of the table that may
be updated as extensions are added to the EFI table types, and a 32-bit CRC so a consumer of an
EFI table type can validate the contents of the EFI table.
EFI_TABLE_HEADER
Summary
Data structure that precedes all of the standard EFI table types.
Related Definitions
typedef struct {
UINT64 Signature;
UINT32 Revision;
UINT32 HeaderSize;
UINT32 CRC32;
UINT32 Reserved;
} EFI_TABLE_HEADER;
Parameters
Signature A 64-bit signature that identifies the type of table that follows.
Unique signatures have been generated for the EFI System Table,
the EFI Boot Services Table, and the EFI Runtime Services Table.
Revision The revision of the EFI Specification to which this table conforms.
The upper 16 bits of this field contain the major revision value, and
the lower 16 bits contain the minor revision value. The minor
revision values are limited to the range of 00..99.
HeaderSize The size, in bytes, of the entire table including the
EFI_TABLE_HEADER.
CRC32 The 32-bit CRC for the entire table. This value is computed by
setting this field to 0, and computing the 32-bit CRC for
HeaderSize bytes.
Reserved Reserved field that must be set to 0.
NOTE
The size of the EFI system table, runtime services table, and boot services table may increase over
time. It is very important to always use the HeaderSize field of the EFI_TABLE_HEADER to
determine the size of these tables.