idmac_desc_64addr
struct idmac_desc_64addr *p;
DESC_RING_BUF_SZ / sizeof(struct idmac_desc_64addr);
(sizeof(struct idmac_desc_64addr) *
(sizeof(struct idmac_desc_64addr) *
struct idmac_desc_64addr *desc64_first, *desc64_last, *desc64;