R_DUART_INCHREG
#define A_DUART_INCHREG(chan) A_DUART_CTRLREG(R_DUART_INCHREG(chan))
delta = read_sbdshr(sport, R_DUART_INCHREG((uport->line) % 2));
read_sbdshr(sport, R_DUART_INCHREG((uport->line) % 2));