Porting the ChibiAkumas to the Elektronika MS-0511

[aberrant_hacker]

At the end of 2018, I started the project. But I worked only occasionally.
Recent events allowed me to spend a lot more time on the game)))

Still, there is much more work to do.

So I decided to create a topic here, to track progress and ask questions.
There is another topic about the project in the "Show and Tell".
But for now, I feel like I have nothing to show, only questions))

[aberrant_hacker]

About the progress

• The main menu level is working, but it launches only Introduction level
• Introduction level partially working
• Sound and music started to working on

The sound and music subsystem quickly turned into a project on its own:

• I started to port full-blown Arkos Tracker Generic Player for future use.
• But the machine has no AY(or any PSG ) chip.
• As a quick solution, I connected the AY chip to a printer port.
• And in parallel working on a sound card for the machine.
• Schematic of the card is finished, and now the most intimidating task has to be done - draw a circuit board)))
  

[akuyou]

Wow, that's absolutely amazing!... it must have taken an incredible amount of work to get any of the game working at all, and as for connecting an AY chip to the UKNC, that's really incredible.

[aberrant_hacker]

as for connecting an AY chip to the UKNC, that's really incredible

In terms of logic, it's not as difficult as it may seem. It rather resembles programming.
The tricky part is in physics. You have to consider what happens on the level of physics to design a circuit board.
This is why it most intimidating for me. And this is why I finally gave up and decided to ask a professional to do the design


Also, some parts of the code were just translated from one assembler to another without deep understanding.
Currently, some of the spite code is not working as expected.
For example:

There is some garbage on a screen when sprite crosses the edges of the screen. And the decapitated body displayed not where it supposed :Confused:

I have a vague idea that one of the reasons is a difference in how the screen memory organized.
CPC byte contains 4 pixels. UKNC byte contains 8 half-pixels (next byte contains the other 8 halves).
And what makes the code work, despite the difference, is the way how PDP-11 treats uneven addresses - it just ignores the least significant bit of an address.

[akuyou]

I'm guessing the sprite on the left is a glitch with the clipping code?

Truth be told, my clipping code was very bad, because I'm awful at maths and stuff!... there was a bug in the final code, where if a code was clipped in the X and Y axis it would mess up... fortunately it almost never happened, so no one noticed!

I'm not sure about the 'body' problem... I can't remember if that was made up of one sprite or two?

[aberrant_hacker]

I'm not sure about the 'body' problem... I can't remember if that was made up of one sprite or two?

The body made up of one sprite. The sprite has some lines to skip, and it looks like the line-skipping breaks something.