ZX DRAWING BOARD (1K ZX80, 1K ZX81)
from ZX Computing 1, Summer 1982, page 90

ZX80 PROGRAM:
- Program 1 [original program name unknown]

This simple little program, quite apart from enabling one to draw pretty
pictures on the screen of one's ZX80, shows how you can control on-screen
movement. You can change the symbol in use and the direction in which you are
moving at any time during the program execution.

When the program is RUN an asterisk (star) it displayed on the screen. To alter
the symbol in use press '5' then 'NEWLINE' followed by the code of the required
symbol and 'NEWLINE'. Changes in the direction of movement can be made by
keying the desired direction code (shown below) and the inevitable 'NEWLINE'.

  7  8  9
   \ | /
  4--+--6
   / | \
  1  2  3

The program uses the following variables:
D - Position on-screen of current symbol.
C - Code of displayed symbol.
A - Direction code.
I - Dummy variable.


Try the following data string, the '/' represents the NEWLINE.

5/128/8/4/2/2/4/4/2/2/2/2/6/6/2/6/8/6/6/6/6/6/
6/2/6/8/6/6/8/4/8/8/8/8/8/6/8/4/4/4/2/2/2/4/4/
4/4/4/4/8/8/8/5/8/9/9/9/9


ZX81 PROGRAM:
- Sketchpad
- Program 2 [original program name unknown]

