WM_NTXDESC
if ((start + num) > WM_NTXDESC(txq)) {
(WM_NTXDESC(txq) - start), ops);
num -= (WM_NTXDESC(txq) - start);
#define WM_NTXDESC_MASK(txq) (WM_NTXDESC(txq) - 1)
#define WM_TXDESCS_SIZE(txq) (WM_NTXDESC(txq) * (txq)->txq_descsize)
if (txq->txq_free == WM_NTXDESC(txq)) {
wm_cdtxsync(txq, 0, WM_NTXDESC(txq),
WM_NTXDESC(txq) = WM_NTXDESC_82542;
WM_NTXDESC(txq) = WM_NTXDESC_82544;
wm_cdtxsync(txq, 0, WM_NTXDESC(txq),
txq->txq_free = WM_NTXDESC(txq);