Controlling a GPIO in Assembly

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    Question: I understand how to put a byte out to a register. How do I control P1(0) without effecting other pins ?

     

    Answer:

    You will have to mask the other bits of the register. You can do so in assembly by the following instructions:

    To set bit 0: or reg[PRT1DR],1

    To clear bit 0: and reg[PRT1DR],~1