nesdev.org

Thanks for the updates sonder. Is your implementation living somewhere out on the web for perusal? I am interested in checking it out. No not yet. It just needs to be taken out of the game project folder and cleaned up. I will do that tomorrow since it's in a good working state and throw it in a SV...

Update: During the past couple days I debugged it and optimized it more. Comparison tests, if/then, for loops and while/until control structures are supported and functioning perfectly. A very small set of opcodes and routines for working with 16-bit numbers were added. On the testing side of things...

If it isn't destructible, honestly sounds like a huge waste. You'll still have to decompress it. Might as well make it stage-based. Well that's the point, I want to be able to see how I can maximize a large decompressed map and do beyond what 2K permits. BTW the game idea is a top-down open world a...

Just curious: what do you need the PRG-RAM for? Are you sure you can't make it work with only 2KB of RAM? Basically primarily to have an easier time of programming. Decompress a large horizontally scrolling map (8-screen wide maximum) in one go and use 16-bit coordinates for objects. It will have l...

Originally I was going to look into beginning UxROM development but the I realized from looking at the wiki that it doesn't have PRG RAM. I checked the other mappers and couldn't find the combination of both CHR RAM and PRG RAM I was looking for, in a discrete mapper like NROM - I don't get why that...

The interesting thing about grey in NES games is that it can be combined with different colors to create the illusion of more colors. Look at Blaster Master for example... they use the same grey to highlight the rocks and the grass, requiring only one palette to color both of them. But you have to ...

However gray is a weird colour choice I'd have picked dark green. Taking a guess, it's probably to work around color count limitations. that's partly correct, however i come from an oil painting background and thought that the dark green was far too dark and saturated. i like grey as a shading colo...

Ever read about Steve Wozniak's Sweet16 interpreter? Neato - no I hadn't heard of that. It isn't practical to have a full 16-bit VM for realtime code (rather I'm going to just have some extra instructions for doing a couple 16-bit operations) but I will have to look into this later for ideas or cod...

I had a eureka moment and figured out a way to speed it up by 1.5x using a tiny bit of self-modifying code, while also saving a significant amount of ROM space. Like hundreds of bytes. An additional improvement is it can now call arbitrary asm, so asm and bytecode can be freely mixed. I am looking t...

It's with a little disappointment that I have to announce that this project has been put on hiatus. Mike and I agreed to cease working on it together for the time being, due to differences in priorities and ability to contribute (basically I became the only one making progress while he was tied up w...

So I've been developing a bytecode interpreter for the NES to solve a few problems. I'm using it to do r&d. Here's why I did it: 1) 6502 is hard - too hard to try out ideas on or get something running quickly. 2) C is not much easier and not space-efficient at all. 3) NES has tight storage, so s...

On NTSC, something 7x8 pixels in size is a perfect square/circle by definition. (Rec. 601 defines the active width of a scanline as equivalent to 280 dots, giving 8:7 PAR that a 7x8 pixel object cancels out.) But on PAL, you're right that 8x11 is closer. I'm not sure what you mean by "invasion...

16x8 has some more interesting caveats i've found through creating graphics within this constraint. when a sprite leaves the top of the screen, it leaves sooner than 8x8 does. 16x8 sprites allow invasion of the background's patterns. use of some tiles as priority-quirk sprites is possible but you ha...

Yeah, when you only have 32KB of PRG-ROM, you shouldn't use a lot of look-up tables. We are going to upgrade to UnROM. Maybe. I flip flop a lot internally on what I want the scope of this project to be. We are in that awkward stage between deciding what to do and experimenting with actual code and ...

Every time I had to do this I used the old "shift and add + throw away lower byte(s)" method. The only way I know to actually speed up multiplications is to use the method explained here . The idea is to build a table using this formula: f(x) = x^2 / 4 and then do f(a+b) - f(a-b) to calcu...