GetRSDP finds the RSDP pointer and struct in memory.

GetRSDPEBDA finds the RSDP in the EBDA.

GetRSDPEFI finds the RSDP in the EFI System Table.

GetRSDPMem is the option of last choice, it just grovels through the e0000-ffff0 area, 16 bytes at a time, trying to find an RSDP.

NewRSDP returns a new and partially initialized RSDP, setting only the defaultRSDP values, address, length, and signature.

RSDP is the v2 version of the ACPI RSDP struct.