[Coco] Mod10 Suggestions

[William Mikrut]

I missed the TSTA -- Done!

I need to have A start at 16.

The reason being I am actually reading the number from right to left.
So I need that A,x   (16,X) then (15,X) and so on offset to process the
numbers.

I don't know of another way to maintain that index while counting down.


On Fri, Feb 17, 2017 at 4:34 PM, William Astle <lost at l-w.ca> wrote:

> You can replace CMPA #0 with TSTA to save one more byte.
>
> Alternatively, you can start with A at 15 and not bother with the DECA at
> the start of the loop. Then replace your CMPA #0 with DECA and use BMI to
> branch if you've gone past 0 (negative). (DEC sets N (negative), Z (zero),
> and V (overflow) correctly. It just doesn't change C (carry))
>
>
> On 2017-02-17 02:58 PM, William Mikrut wrote:
>
>> Thank you for all of the great suggestion!
>>
>> I have implemented them and the byte count shrunk from 79 -> 65 ( Almost
>> 20% reduction) and it actually runs faster without the excessive loop
>> overhead.
>>
>> The only thing I didn't try was storing a variable in the DP ($0003)
>> because I always want my code to be completely independent of there it's
>> loaded.
>>
>> Here is the revised version 2!
>>
>> (A CoCo based CCD reader would be Awesome!
>> I wonder if Ingenico would be on board!!)
>>
>>
>>
>> On Fri, Feb 17, 2017 at 4:34 AM, Mark McDougall <msmcdoug at iinet.net.au>
>> wrote:
>>
>> On 17/02/2017 5:57 PM, Dave Philipsen wrote:
>>>
>>> Here's a problem.  It's not the credit card digit itself that is being
>>>
>>>> tested for odd/even.  It's the position of the digit.  So you need to do
>>>> a  'bitb #1' instead of a 'bita #1'.
>>>>
>>>>
>>> Good catch - thanks!
>>>
>>> Regards,
>>>
>>> --
>>> Mark McDougall
>>> <http://retroports.blogspot.com.au>
>>>
>>> --
>>> Coco mailing list
>>> Coco at maltedmedia.com
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>>>
>>>
>>>
>>>
>>>
>
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