[Coco] CaChars - SCW-like screen characters for Color BASIC

[Juan Castro]

I'm only testing if the four upper bits of the PIA at $FF22 are all ones.
Are you saying that can cause problems in the CoCo 3?

I can't delve into CoCo code here at work, I'll take a look at that when I
get home tonight. Meanwhile, what's the most canonical/portable way of
testing whether I'm running in a CoCo 3? (So I don't try to hook CLS's
vector if I am)

Thx,
Juan

On Wed, May 16, 2012 at 10:31 AM, Robert Gault <robert.gault at att.net> wrote:

> Juan Castro wrote:
>
>> Well, I just found out the CoCo 3 destroys the capability to hook CLS. The
>> patched code doesn't bother to call the RAM vector. That's, like, rude,
>> man.
>>
>> OK, I'll just define CHR$(12) (Form Feed) as the CLS character.
>>
>>
> Juan,
>
> Seems to me that the CLS vector is still being used by the Coco3 but there
> is additional patching.
>
> What may be an issue is TSTHIRES. The Coco3 definition of hi-res is to
> look at $E7 to see what screen mode is present: 0=low-res, 1to4=hi-res.
> That means you can't use the current TSTHIRES to replace the test at $8C46
>
>  pshs cc
>  tst <$E7
>
> I think TSTHIRES is looking at the PIA to see whether low-res text or
> graphics is on.
>
> Robert
>
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