+ @retval EFI_NOT_FOUND Some necessary information cannot be found. \r
+\r
+**/\r
+typedef\r
+EFI_STATUS\r
+(EFIAPI *EFI_ACPI_S3_SAVE)(\r
+ IN EFI_ACPI_S3_SAVE_PROTOCOL * This,\r
+ IN VOID * LegacyMemoryAddress\r
+ );\r
+\r
+/**\r
+ This function returns the size of the legacy memory (meaning below 1 MB) that is required during an S3\r
+ resume. Before the Framework-based firmware transfers control to the OS, it has to transition from\r
+ flat mode into real mode in case the OS supplies only a real-mode waking vector. This transition\r
+ requires a certain amount of legacy memory. After getting the size of legacy memory\r
+ below, the caller is responsible for allocating the legacy memory below 1 MB according to\r
+ the size that is returned. The specific implementation of allocating the legacy memory is out of the\r
+ scope of this specification.\r
+\r
+ @param This A pointer to the EFI_ACPI_S3_SAVE_PROTOCOL instance.\r
+ @param Size The returned size of legacy memory below 1MB.\r
+\r
+ @retval EFI_SUCCESS Size is successfully returned.\r
+ @retval EFI_INVALID_PARAMETER The pointer Size is NULL.\r
+ \r