LSR_THRE
while ((com_port->lsr & LSR_THRE) == 0)
while ((INP(LSR) & LSR_THRE) == 0)
while ((com_port->lsr & LSR_THRE) == 0)
while ((com_port->lsr & LSR_THRE) == 0)
} while (timo-- > 0 && (lsr & LSR_THRE) == 0);