DEMO SOURCE CODES
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By Pirx/O5/BC


On the second side of the MegaZine you will again find some source code made by Pirx/O5/BC.
This time it is a special demo for Micro Discount from England. I called it a 'special' demo because it requests that DOS is present in memory (curious, eh.).
Demo after running loads two data files into memory. It enabled making different texts, etc.
Read about the demo below.


The demo consists of three files:

AUTORUN.SYS
The main file containing a code, graphics and music.

TEXT.TXT
ATASCII scrolltext. It can be made and edited under The First XLent Wordprocessor.
Every character except A-Z, 0-9 and some punctuation marks (. , ! ? -) are treated as blank spaces.
Some chars have special functions - they turn on options of horizontal and vertical scrolling of the main scroller.
 < |turn on slow horizontal scrolling
 = |fast hscrol
 > |very fast hscrol e) hscrol
 ^ |smooth vertical jumping
 _ |no vjumping
 / |crazy vjmp

Lenght of this text must be shorter than $4100 (dec 16,640) bytes.


WATER.TXT
another text file which contains wave data for "ATARI logo F/X" at the top of the screen.
I didn't like the current version of the wave, so I decided to make an ability to change it easily.
This file must NOT contain any chars except for 0,1,2,3,4,5,6,7.
This is why it has to be edited under a text processor like First XLent (or other where EOLs are not necessary).
Meaning of those numbers is ho skip after showing former line of "ATARI logo".
Simpler - after "0" computer will show the same line again, "1" makes it show  the next one, "2" - the second after current, "3" - third, etc, etc.
Every frame (1/50 s) computer takes 46 (number of showed lines) values and built a picture of them.
Then the pointer of this table is incremented and next time it takes those 46 numbers from one byte higher. Sorry, but I had to include this nonunderstandable stuff to allow you to operate my program.

Maybe an example will help:
11111111111111111111111111111232111010010111101111111111234543211111111110111011111232111.......and so on
THE DATA SHOULD BEGIN WITH ABOUT 50 "1"'s !!!
At the end program automatically adds $40 "1"'s, so you needn't do it.

Lenght of "WATER.TXT" file shouldn't be bigger than $0FC0 (dec 4032 bytes). It is about 32 single density sectors.

On this disk you can find a complete source code of this demo (MAC65 format) in case you want to change something (colors, music, add next F/X, etc).
To assemble it you have to copy all *.M65 and *.SYS files to ramdisk (D8:), load into MAC65 file DISC4.M65 and assemble it on (ram)disk - ASM,,#D8:DISC.COM.
You will get the pure code file without music module.
To link music and code load to cleared memory two music files (M3.CMC and M3.REP - if you use DOS XL 2.xx try MUS command) than
DISC.COM file and save it (SAV DISCOUNT.COM,2300,61FF).
Than append START.COM to the end of DISCOUNT.COM and save it as AUTORUN.SYS on bootable dos disk.
Don't forget to save on that disk TEXT.TXT and WATER.TXT files. If you are lucky, it will be working Micro Discount demo.

There are no SHORT.SYS and IO.MAC files on the disk, because they are not a Public Domain or a proprerty of Our 5oft. I count that other guys make those files for MegaMagazine readers... Sorry.

Pirx/Our 5oft/Bloody Coders.