UART_LSR
while (!(In8(UART_LSR) & (1<<6))) {
while (!(In8(UART_LSR) & (1<<0)));
if (!(In8(UART_LSR) & (1<<0)))
while (!(In8(UART_LSR) & (1<<6)));
while (In8(UART_LSR) & (1<<0)) {