I has the code. Took me a long while to understand precisely how the canonical code works, but when you see the codes laid out it becomes clear how to figure out to do the decoding without having to scan the entire code table.

Here's a blog post where I go into a bit more detail.

https://github ...

Thanks guys.

Lots of helpful info at Garth's website, that place is a bit of a treasure trove.

Dwight- strings is the thing for the adventure game I am working on, you might like some of the posts I made on string compression. My github blog is really more of a personal diary than something for ...

'XY' is a 16-bit pointer to a parameter block,

This is a good idea for when the parameter block is dynamic- I hadn't thought of that and have been stuffing things into the zero-page which takes the extra STA/STX.

I have the luxury of using a LISP program to generate most of the assembly so I can ...

An alternative to the parameter passing described at NesDev. The main difference is that the target routine is responsible for calling the parameter-extracting code. (I'm guessing this is a well used technique- I would be interested to know where it was first used and what the most efficient ...

I have been posting over in the General section about an adventure game project I am working on. Out of that has come the need for image compression. Rather than just pick out the best one from the demoscenesters bag of tricks I decided the best way to learn about it was to do it. It is also a topic ...

Some example sizes for images,


Original Simple Best

cellardoor 1352 1073 995 26%
porsche 1352 1182 1042 23%
maxine 1352 1054 762 44%


I've implemented the simple scheme, but am working on the extension to make it a bit better. This involves removing some of the constraints in the LISP ...

Finally, some 6502. I spent far too long fiddling with the compression algorithm but I finally came up with something that works. Now I can put images in the top right corner of the screen.

Image no longer available: https://github.com/djangojames/exploratory/blob/master/blog/odysseus.png?raw=true ...

Thanks, that's useful information. The black scanlines are part of the my renderer, so reducing the harshness should be straightforward (half bright alternating lines?) Scaling to a non-integer aspect ratio may be trickier with the code I have- it's just a simple blit at the moment. I'll have a look ...

Thanks Garth

I have begun jotting down my thoughts on it here, https://github.com/djangojames/explorat ... er/blog.md

I will post something to the Programming section when I have some code to show.

Final images... I promise. Next I will post some actual 6502- I'm going to move onto image compression. Is there a section for this, or should I just keep posting here? What I really need is some of you assembler wizards to critique the number of cycles I am using...

Image no longer available ...

And more,

So I had my first go at images! Woo. No 6502 compression yet, that's next on the list. For now just experimenting with converting images to use...

Image no longer available: https://github.com/djangojames/exploratory/blob/master/blog/conversion.png?raw=true
https://github.com/djangojames ...

I am now wondering if the SSD failed because of my misunderstanding of how mmap works- I have never had a HDD fail before in 20 years, guess I have been lucky.

Here's the same text in the two other fonts, thanks for all your suggestions.

Image no longer available: https://github.com/djangojames ...

I was going to upload a new screen shot with the other two fonts, a gothic, medievally one and a futuristic one, however my Ubuntu laptop has decided to die with all the work I did. What is the MTTF for an SSD? It was about four years old...

I had the colour attributes working, with the C64 palette ...

Thangs Big Ed for the welcome and to everyone else for their replies. I will no doubt be tapping people for their knowledge, especially any C64 lurkers with specific knowledge of VIC-II.

Yes, the wobbly font. It's going to be polarising all right. I kind of like it, but I agree that it might be ...