how to check the serial port see the data is ready to be picked up ( 1 indicates ready and 0 indicates not ready )

Give a sequence of assembly language nstructions to check the serial port to see it data is ready to be picked up. The "A" register should be "t" to indicate data is ready or to" to indicate that it is not ready. Give a sequence of assembly language nstructions to check the serial port to see it data is ready to be picked up. The "A" register should be "t" to indicate data is ready or to" to indicate that it is not ready