LM_MEDIUM_TYPE_MASK
#define GET_MEDIUM_TYPE(m) ((m) & LM_MEDIUM_TYPE_MASK)
(m) = ((m) & ~LM_MEDIUM_TYPE_MASK) | (t)
#define GET_MEDIUM_TYPE(m) ((m) & LM_MEDIUM_TYPE_MASK)
(m) = ((m) & ~LM_MEDIUM_TYPE_MASK) | (t)