(&(((union e1000_adv_tx_desc *)((R).desc))[i]))
#define E1000_TX_CTXTDESC_ADV(R, i) \
(&(((struct e1000_adv_tx_context_desc *)((R).desc))[i]))
-#define E1000_GET_DESC(R, i, type) (&(((struct type *)((R).desc))[i]))
-#define E1000_TX_DESC(R, i) E1000_GET_DESC(R, i, e1000_tx_desc)
-#define E1000_RX_DESC(R, i) E1000_GET_DESC(R, i, e1000_rx_desc)
/* board specific private data structure */