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Nybble Help

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    Nybble Help

    If I XOR the upper Nybble of a tasty Byte, will I have more friends?

    #2
    Originally posted by DimPrawn View Post
    If I XOR the upper Nybble of a tasty Byte, will I have more friends?
    Only of a certain 'type'
    Me, me, me...

    Comment


      #3
      If you do it twice you'll be where you started.

      See the (bit)pattern?

      Comment


        #4
        Originally posted by Churchill View Post
        If you do it twice you'll be where you started.

        See the (bit)pattern?
        Except in the case where you XOR it with itself... the first time will zero it, and the second will just leave it set to zero.

        This is why the "swap two values without an intermediate location" trick only works if you can guarantee that the two locations holding the values are different.


        Comment


          #5
          Originally posted by NickFitz View Post
          Except in the case where you XOR it with itself... the first time will zero it, and the second will just leave it set to zero.

          This is why the "swap two values without an intermediate location" trick only works if you can guarantee that the two locations holding the values are different.


          Take the 'mask' off.

          Comment


            #6
            Originally posted by Churchill View Post
            Take the 'mask' off.
            You can't - if the source, mask and destination are all the same location (i.e. the value at that location is XORed with itself and the result stored back into that location in one atomic operation), then the mask has become zero.

            Comment


              #7
              Nybble - that was a cool mag. dedicated to Apple II. i can remember entering hex code by hand from the pages. What was hilarious is watching terminator and seeing the code scroll by.
              McCoy: "Medical men are trained in logic."
              Spock: "Trained? Judging from you, I would have guessed it was trial and error."

              Comment


                #8
                I have absolutely no idea what any of you are talking about
                ǝןqqıʍ

                Comment


                  #9
                  Originally posted by DiscoStu View Post
                  I have absolutely no idea what any of you are talking about
                  Never mind Junior

                  Before your time son
                  Confusion is a natural state of being

                  Comment


                    #10
                    Originally posted by DiscoStu View Post
                    I have absolutely no idea what any of you are talking about
                    That's why it's called an exclusive or

                    Comment

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