Was keeping this under wraps but DIABLO comes to the Colecovision

[Captain Cozmos]

I've been playing this and have identified at least 3 bugs I have to rewrite in order to release this rom.

 

Still under 7k

 

This game is one of the simplest of games when you decipher what each thing does.

 

Basically how it works is it prints several predefined 8x8 but those 8x8 are tabled into 4x4 4 blocks that scroll to the next position.
There is no memory other than the high score and the ram is used for scrolling purposes and general crap.

No set bitmap to remember.  The ball reacts to whatever the adjacent square is in real time.

What I mean by no memory is that there is no set map outside of a general set of rules so you are not constantly moving stuff just to get to the next square.

 

When you think about it.  All it has to do is encounter a particular number than move the sprite in a manner that represents the 8x8 pattern.
 

There are a total of 3 sprites in 3 different colors plus black.
When the ball passes under a bridge be it the side walls or pattern it is actually going behind a sprite square for that color region.  Red, green (border) Yellow (track).

This gives the illusion that it is going under something then the pattern changes to it's match but without those two lines that formed the bridge.

 

It's not as complicated that you would think when playing it.

 

My problem with this, along with all these other roms, are the shifting pointers.

 

I am finding that a lot of these tables do not have a visible, permanent address that you can define a label too in order to recompile.
A lot of these use something to the effect of LD BC, ??  ADD HL, BC, pass that to IY then jump to that address that was defined 35 years ago when compiled.

 

So, if anyone has any bright idea on how to track down because I am going through the math until my eyes are puffy and swollen and nothing concrete.

I am however learning a lot about linking classes and routines together through IX and IY.
Apparently you can come up with some complicated stuff that will run with just one call and let IX do the rest.

Diablo has a custom NMI that runs off a table which also aids in scrolling the pattern.

This also exchanges with the stack pointer for a bit of speed up.

I have yet to find any time manager in order to control the speed of the game

 

There is one other issue.
I have not used original equipment with this recompiled version.
 

When using the ADAM Keyboard when you double tap the keys a whole row of tiles move.

Since I removed the keyboard function and now only use the controller I can not duplicate that action as of this writing.

The game is playable and to prove it here is a rom that you can test to show you I am not full of ****

 

 

 

CC

Diablo v6.rom

Edited July 29, 2022 by Captain Cozmos