[Coco] Assembly lang questions

[Arthur Flexser]

This is the difference between how characters are represented in Ascii vs
how they are represented in the CoCo's screen memory, I assume.  If you
print with Basic's print commands, or by using the CHROUT routine, chr(32)
will display as a space, since 32 is space's Ascii value.  But if you poke
a 32 into screen memory, it will display as a reverse video space.
(Decimal 96--$60 instead of $20--would poke in as a regular space.)  Same
with other text characters--reverse video instead of the regular character
if you poke them in.

If you use Basic's routines, the cursor position is in $88-89.

Art

On Thu, Oct 11, 2018 at 7:15 PM, Salvador Garcia via Coco <
coco at maltedmedia.com> wrote:

> Hi all, I am following the Long Branch Never video where Paul  displays
> the message HELLO WORLD on the screen.
> He uses char(32) for the space, but it displays as black. To fix this he
> substituted the ASCII from 32 to something else (I think it was 76?) That
> printed out the space as expected. What I did not understand is why chr(32)
> displayed as a black box.
>
> I understand that reverse video chars are lower case, but I never heard of
> a lower case space :-).
>
> He later modifies the program to start displaying chars at $500 which
> pushed the text line below the copyright notice. The cursor blinked one or
> two lines above the displayed text, so this got me wondering. Is there any
> way to know the cursor's position?
>
> I am enjoying this video series and also Steve Bjork's series on COCOTALK!
>
> Salvador
>
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