RSDP: Difference between revisions
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==Validating the RSDP==
{{In Progress}}
If the RSDP revision field is zero, it is ACPI version 1.0 and the first structure should be used, otherwise it is the second structure that should be used, as that has data about the [[XSDT]], an extended [[RSDT]].
Before the RSDP is relied upon you should check that the checksum is valid. For ACPI 1.0 (the first structure) you add up every byte in the structure and make sure the lowest byte of the result is equal to zero. For ACPI 2.0 and later you'd do exactly the same thing for the original (ACPI 1.0) part of the second structure, and then do it again for the fields that are part of the ACPI 2.0 extension.
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