TN40_REG_TXD_WPTR_0
for (i = TN40_REG_TXD_WPTR_0; i <= TN40_REG_TXF_RPTR_3; i += 0x10)
TN40_REG_TXD_RPTR_0, TN40_REG_TXD_WPTR_0);