ACPI_DESCRIPTOR
ACPI_DESCRIPTOR *Descriptor;
ACPI_DESCRIPTOR, &Element->UserSpace);
#define ACPI_GET_DESCRIPTOR_PTR(d) (((ACPI_DESCRIPTOR *)(void *)(d))->Common.CommonPointer)
#define ACPI_SET_DESCRIPTOR_PTR(d, p) (((ACPI_DESCRIPTOR *)(void *)(d))->Common.CommonPointer = (p))
#define ACPI_GET_DESCRIPTOR_TYPE(d) (((ACPI_DESCRIPTOR *)(void *)(d))->Common.DescriptorType)
#define ACPI_SET_DESCRIPTOR_TYPE(d, t) (((ACPI_DESCRIPTOR *)(void *)(d))->Common.DescriptorType = (t))