Scott Dattalo wrote:
>
> Guys & Alice
>
> It seems like there's been several questions about delay loops in the
> last few weeks. So I thought it'd be interesting to see if we could
> turn
> this into a challenge:
>
> Create a delay loop that can loop for up to 2^16 times while
> mininmizing
> the number of cycles per iteration. For example:
>
>   clrf   lo
>   clrf   hi
>
>   movlw  1
>
> loop:
>
>   addwf  lo,f    ;increment the low byte
>   skpnc          ;if low byte rolls over
>    addwf hi,f    ; then increment the high byte
>
>   skpc           ;We're done if the high byte rolls over.
>    goto  loop
>
> This will loop 2^16 times and each pass through the loop is 6 cycles.
>
> I've got a solution that takes 5 cycles per iteration and doesn't use
> W
> (oh I shouldn't have said that - now you know the answer!).
>
> Any takers?
>
> Scott



        clrf    lo
        clrf    hi
loop:
        incf    lo, f
        skpnz
        incfsz  hi, f
        goto    loop

Bob Fehrenbach
Wauwatosa, WI