Write a function that returns zero if INDF is a power of two, else returns
non-zero.

For example, here's one of the most inefficient ones I can think of:


    clrw
loop:


    btfsc   indf,0     ;count the 1's
     addlw  1

    clrc
    rrf     indf,f     ;move the next bit to bit 0

    skpz               ;If more 1's, loop more
     goto   loop

    xorlw   1          ;If only one 1, then we found a power
                       ;of 2, so return a zero.

    return


Hint: The most efficient one I can think of off the top of my head only takes 6
cycles (counting the return). I'm quite certain a 5 cycle version lurks in the
midst.

Scott

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