Call on C language experts to enlighten me

Http://topic.csdn.net/u/20101124/19/4e061ce6-07ee-4cdf-98ee-f249f9919068.html? 10951

 

// Execute different functions () based on the received data when reading the serial port ();
// In this way, the data can only be read once, and then how to write data to the serial port cannot be read.
// How can I modify it to implement it: once there is data, it will interrupt the current funtion (), re-read and execute the new function.
// Isn't the serial port itself an IRQ operation? I used cortex m0.

While (1)
{
Data = receivebyte ();
Switch (data)
{
Case 'A ':
Function1 ()...
Break;

Case 'B ':
...
Break;
Case 'Z ':
...
Break;
Default:

Break;
}

}