BTH_PSN_MASK
qp->send_psn &= BTH_PSN_MASK;
swq->start_psn = sq->psn & BTH_PSN_MASK;
sq->psn = (sq->psn + 1) & BTH_PSN_MASK;
sq->psn = (sq->psn + pkt_num) & BTH_PSN_MASK;
sq->psn = (sq->psn + pkt_num) & BTH_PSN_MASK;
sq->psn = (sq->psn + pkt_num) & BTH_PSN_MASK;
swq->next_psn = sq->psn & BTH_PSN_MASK;