RX_MASK
head = pp->r_head & RX_MASK;
while (head == (pp->r_tail & RX_MASK))
pp->r_head = (head + 2) & RX_MASK;
(head = pp->r_head & RX_MASK) != (pp->r_tail & RX_MASK) &&
pp->r_head = (head + 2) & RX_MASK;
pp->r_head = pp->r_tail & RX_MASK;
head = pp->r_head & RX_MASK;
while (head != (pp->r_tail & RX_MASK)) {
head = (head + 2) & RX_MASK;
head = pp->r_head & RX_MASK;
if (head == (pp->r_tail & RX_MASK))
pp->r_head = (head + 2) & RX_MASK;
bus_space_write_1(bst, bsh, DLCR_RX_INT_EN, RX_MASK);
bus_space_write_1(bst, bsh, DLCR_RX_INT_EN, RX_MASK);
#define CLEAR_RX_ERR RX_MASK /* Clear receive and errors */