ChibiAkumas ASM Programming Forum

Hi Keith,

It's been a while since I last posted on here. Hope you're doing well. I've still been dipping in/out of CPC Z80 development. Here's something that I've been working on lately and thought I'd post a video (link) for all to see.

https://youtu.be/hxBVr9IWEqE

I set myself a target of ...

Hi Keith,

Glad you liked it. I appreciate your words of encoragement. My goal is to learn code (no doubt thanks to you) and try and share with other users what I have learnt in a way of producing some simple programs. There's no doubt that it took me a while to suss out the logic for the wrapping ...

Hi All,

I've been working on learning how to wrap sprites around the screen. The effect being that when the sprite starts to leave one side of the screen it begins to appear on the opposite.

My example code works in the y-axis (I think x-axis is going to be tricky) and moves 1 pixel at a time ...

Hi Keith

I was browsing through the CPCWiki forum the other day and came across a post in which someone showed a firmware function which calculated the screen address based on x/y coordinates. The call was to &BC1D – Have you ever come across this? I immediately looked it up in the firmware ...

I think Keith's code is slightly different from what you are trying. He doesn't use the WaitChar call for user input. Instead he "pokes" the values directly to the source memory locations. Then having performed the math operation using assembly, he fetches (using peek) the result directly from ...

Hi,

I think the problem is with the &BB06 call. According to the firmware register 'a' holds the value of the character, which I think it means by that the ASCII code. Of course that value will not be the literal value your supplying. For example, if you entered 1 into b the value it's going to ...

Do you have any 'future plans' for this program?... for some reason it immediately makes me think of the 'Light cycles' Tron game

The plan is to develop a very simple (but addictive) game where the player (the pixel you see now) has to go through a vertical line (like a force field) which has a ...

Hi Keith,

Thanks for the example code. I've been looking through it and have started to understand how you are doing things. It's really puzzling why the Amstrad screen (and Spectrum) RAM was never designed to be linear. Using C on the PC I used to find it much easier to work with the screen memory ...

; 'Pixel Perfect'
; by Indy
; A big thanks to KeithS the author of Chibiakumas game.
; You encouraged me to learn assembly again.
;
;
;
; Just a simple program to learn how to program in Z80 in particular the
; Amstrad CPC range of 8 bit computers. I grew up with these machines and have always ...

Hi Keith,

I'd first like to say how glad I am you setup this forum. I think it's really going to help users out a lot. And also my personal thanks to you for giving up so much of your free time to teach assembly - greatly appreciated. It's a shame you weren't teaching 30 years ago when I was much ...