When a platform which doesn't support ACPI 1.0 (no XSDT) and FADT is not produced at the first time when ACPI table is published, GetCenturyRtcAddress() unconditionally deference Rsdp->RsdtAddress but Rsdp->RsdtAddress is 0 in this case. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com>