Actually, this has an AVERAGE number of cycles per loop of very close to 3,
since the first goto is only skipped 1/256th of the time.

Sean

At 09:42 AM 5/7/99 +0800, you wrote:
>Hi Scott,
>
>How about, 5 cycles per loop, doesn't use W:
>
>        clrf    lo
>        clrf    hi
>
>loop    incfsz  lo,f
>         goto   $+2
>        incfsz  hi,f
>         goto   loop
>
>regards,
>Reggie
>
>--
>e-mail: rberdin@bigfoot.com
>ICQ#:   31651436
>URL:    http://www.bigfoot.com/~rberdin
>
>
>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
>
|
| Sean Breheny
| Amateur Radio Callsign: KA3YXM
| Electrical Engineering Student
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