Apple IIc+ boot disk for DOS3.3

From: Derek Peschel <dpeschel_at_eskimo.com>
Date: Sun Aug 6 04:25:10 2000

> To plot lines or points in lo-res:
>
> Points:
>
> PLOT x,y
>
> Lines:
>
> PLOT w,x TO y,z
>
> w,x,y,z=0-39

You can't do that. You can only do:

HLIN x1, x2 AT y

or

VLIN y1, y2 AT x

And if you POKE 49234,1 you will get a full 40x48 screen of graphics. Do
POKE 49235,1 to get the four-line text window back. There are a number of
other "soft switch" locations. POKE 49236,1 selects graphics page 1 and POKE
49237,1 selects page 2. The last two are most useful in high-res mode,
because low-res page 2 is the default starting location for BASIC programs.

Incidentally, low-res and text modes use the same memory locations but
interpret them differently. So of course there is a text page 2 but you
still have to move your program to use it (just as with low-res page 2).

> To get into the monitor:
>
> CALL -151
>
> L - list a section of memory (example: 300L)
> G - executes instructions (example: 300G)

To get out of the monitor:

Ctrl-C Return - return to BASIC

There are, of course, many other features in the ROM; it's just a matter of
digging up the programming info. And (since you have such a late member of
the ][ series) there are also features in the hardware, such as double-
resolution text, low-res, and high-res modes, that the ROM was never updated
to handle. However, you might try

PR#3

and see if you get 80-column mode.

-- Derek
Received on Sun Aug 06 2000 - 04:25:10 BST