George,
I simulated your patch in VirtualT and with light testing it seems to
work.  Nicely done.
cheers


On Thu, Dec 19, 2024 at 7:57 AM Stephen Adolph <[email protected]> wrote:

> Wow, well thank you very much George.
> It did not even remotely occur to me that this problem would have shown up
> in the model 1 ROM.
>
> So this code snippet tracks back to an original Microsoft BASIC that must
> have been written for 8080; the Model 1 pre-dates the Model 100.
>
> very cool!  This is a hek of a lot better than my crude 39 byte
> replacement patch!
>
> Do you mind if I post your answer on the VCFED forum thread I started on
> this subject?
>
>
>
> On Thu, Dec 19, 2024 at 3:33 AM George Phillips <[email protected]> wrote:
>
>> And just after hitting send I realize the Z-80 version can be one byte
>> shorter still:
>> LD A,($40AF) SUB 3 CP 8-3 JR NC,_25E5 OR A SCF RET _25E5: OR A RET --
>> George
>>
>

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