RED ARROW

by Menno van der Star



Well it's not, actually, it's a variety of colours, but red sounds

nicer. This routine is the work of Menno van der Star who, with a name

like that, could only come from the Netherlands. It does the mind-

bogglingly useful job of giving you a little pointer which you can

move round the screen and use to select icons, draw pictures or

anything like that. The code works under interrupt mode two, so once

you've run it the computer can get on with running your Basic program

while the pointer moves around as a "background task" (100%

computer-speak there).



Usage

Couldn't be more straightforward. Type in the Hex with, of course, the

Hexloader (check out issue 45 for more info on that), and save it.

Then reset the computer, put it into 48k mode if necessary, CLEAR

64999 and then load the code back in.



When you RANDOMIZE USR 65000, up it comes (fnurk). The arrow can be

moved around using Q, A, O and P, and M "fires". It's best if you put

the computer into some kind of a loop at this point, otherwise loads

of letters appear at the bottom of the screen. The longer you hold

down a key, the faster the arrow moves, but it never goes off the

screen.



When it comes to actually using the thing, you'll find that 65485

holds the x position of the tip of the arrow and 65486 holds they

position.



When you press M, 65487 changes from nought to one. By peeking these

addresses and getting your program to respond accordingly, you'll find

you can generate a masterpiece in minutes.



If, for some perverse reason, you want to get rid of the arrow,

RANDOMIZE USR 65006.