On Wed, 5 Apr 2017 16:25:23 -0400
Mike Nugent <[email protected]> wrote:

> LOL I think it’s the other way around these days.

Huh? I'm just another failed CS student who never finishes anything.

> I took another look, and it appears the address Tandy gave you is
> where it checks to see whether CTRL-C or CTRL-S is pressed, setting
> the carry flag if so. Here’s what this area of ROM looks like in my
> notes:
> 
> ———   
> KEYX
> 7270H - Check keyboard queue for pending characters
>          Exit:
>                 A - Destroyed
>            Z flag - Set if character pending
>            C flag - Set if break is present
>          Note: called via CHSNS

Works as advertised.
> 
> CTLCHK
> 7283H - Check for break (Control C) or wait (Control S)
>          Exit:
>                 A - Destroyed
>            C flag - Set if Control C or S
>            Z flag - Set if no control C or S
>          Note: called from KEYX (7270)
> 
Experimentally, it looks to me that this returns Z set if no (^C or ^S)
or Z clear if (^C or ^S). I can't get it to return C set ever.


> BRKCHK
> 729FH - Check to see if SHIFT BREAK is being pressed.
>          Exit:
>                 A - Destroyed
>            Z flag - Set if shift break is being pressed
>            C flag - Set if shift break is being pressed

Yes, this one sets both Z and C! As advertised.
> 
> 72B1H - Scan BREAK, CAPS, NUM, CODE, GRAPH, CONTROL, and SHIFT key
> column of keyboard.  Reset the bit in the A register that corresponds
> the key being pressed
>          Exit:
>                 A - Each reset bit corresponds to a key being pressed 
>                     (BREAK=bit 7, CAPS=bit 5, etc.)

And I just plain didn't have this one!
> ———   
> 
> I think I’ll have to post this version of the maps somewhere soon.
> Just have to deal with some urgent business first. Meantime, hoping
> the above is helpful.

Oh yes. You're a lifesaver!
> 
> I’m also going to send a copy (about 93Kb) to your sdc.org address if
> you say it’s okay.

That would be awesome! Thanks!


> 
> — Nuge —
> 
Thanks,
Willard

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