MAX_BIT
#define ENCODE_ERROR(StatusCode) ((RETURN_STATUS)(MAX_BIT | (StatusCode)))
#define DXE_ERROR(StatusCode) (MAX_BIT | (MAX_BIT >> 2) | StatusCode)
#define PI_ENCODE_WARNING(a) ((MAX_BIT >> 2) | (a))
#define PI_ENCODE_ERROR(a) (MAX_BIT | (MAX_BIT >> 2) | (a))
(unsigned long)(StatusCode & ~MAX_BIT)