[Coco] [CoCo] The Trials to disable RS232 Status

[Mathieu Bouchard]

Le 2017-10-02 à 09:54:00, David Ladd a écrit :
> On Sun, Oct 1, 2017 at 12:39 PM, Darren A <mechacoco at gmail.com> wrote:
>> David, not a big deal, but you could cut the number of POKEs in half by
>> changing the two instructions to BRN rather than NOPs.
>>
>> POKE &HA2C7,&H21:POKE &HA2F7,&H21
>
> ​Darren, that is a good idea.  I didn’t know there was a branch never
> instruction.  Otherwise I would have used it. :D Thank you :)

On the 6809, every conditional jump has its opposite. It's also the case on the 
8086 series, where flipping bit 0 of the opcode reverses its meaning, except 
that the 8086 series doesn't have an always/never pair, it has a parity even/odd 
branch instead.

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| Mathieu BOUCHARD --- tél: 514.623.3801, 514.383.3801 --- Montréal, QC