Search found 1422 matches

by Drag
Fri Jul 01, 2022 5:11 pm
Forum: NESdev
Topic: Different behaviour between real NES and Emulators in Battle City
Replies: 30
Views: 1245

Re: Different behaviour between real NES and Emulators in Battle City

I'm glad this was straightened out, because I absolutely could not find anything on the cartridge-side that jumped out at me as something that would cause that kind of a fault (but again, I'm not as familiar with electrical engineering to know for sure. Meaning, if it were bus capacitance or access ...
by Drag
Thu Jun 30, 2022 11:01 am
Forum: NESdev
Topic: Different behaviour between real NES and Emulators in Battle City
Replies: 30
Views: 1245

Re: Different behaviour between real NES and Emulators in Battle City

The PPU is the interface for reading and writing on the PPU bus, so there's no way for anything connected to the PPU bus to know whether the PPU is reading on behalf of the CPU, or reading as part of normal screen rendering. If the cartridge blocks CHR-ROM reads, then the PPU would be unable to disp...
by Drag
Wed Jun 29, 2022 9:12 pm
Forum: SNESdev
Topic: Does Jurassic Park use pseudo high-res mode?
Replies: 86
Views: 2472

Re: Does Jurassic Park use pseudo high-res mode?

Well, not as teletext. It was just a regular video channel displaying the output of a teletext machine, so I'm not sure that it really counts. Just they usually had pleasant "elevator music" kinda stuff to go along with it, from what I remember. Sorry for continuing the tangent, but this ...
by Drag
Mon Jun 27, 2022 7:10 pm
Forum: General Stuff
Topic: Trying to devise some ways to extend my gameplay
Replies: 4
Views: 542

Re: Trying to devise some ways to extend my gameplay

The most fun I have in games like these is when the enemies have complex but predictable (and manipulable) AI that goes beyond a simple "go straight to the player" strategy. Crazy Castle 2 is my usual go-to when I refer to this, but Door Door and BurgerTime do similar things too with how t...
by Drag
Wed Jun 22, 2022 7:47 pm
Forum: SNESdev
Topic: camera scroll walls
Replies: 10
Views: 3419

Re: camera scroll walls

If you're asking because you're looking for ideas on how to implement camera cues, then think of them like you're defining an arbitrary region in your level where, when the player enters this region, certain restrictions are applied to the camera's behavior. When the player exits the region, the cam...
by Drag
Fri Jun 17, 2022 6:48 pm
Forum: NESdev
Topic: CRC routines as PRNGs
Replies: 50
Views: 22695

Re: CRC routines as PRNGs

A few years ago someone brought up CRC routines that essentially do 8 LFSR ticks at a time, and I ended up applying the concept to 16, 24, and 32 bit LFSRs, which I published here: Github: prng_6502 With those, I did a brute force search of all taps that gave maximal length, which had properties th...
by Drag
Fri Jun 17, 2022 5:02 pm
Forum: NESdev
Topic: CRC routines as PRNGs
Replies: 50
Views: 22695

Re: CRC routines as PRNGs

Hey all, 10 years later, I've figured out a better way to generalize the "shortcut" method of clocking a Galois LFSR multiple times in one go. Apologies if I'm covering old ground, but I've actually come back to this thread several times for reference, which is why I'm updating it instead ...
by Drag
Mon Jun 13, 2022 10:13 pm
Forum: nesdevWiki
Topic: turn off syntax highlighting in non-code code boxes
Replies: 3
Views: 327

Re: turn off syntax highlighting in non-code code boxes

It looks like ``` is the markup for code? In the nesdev wiki, all you have to do to get a non-colored monospaced plain text area is to have a leading space on each line. Does that work there? Using ``` to mark code blocks is pretty standard markdown notation. Sometimes, markdown parsers allow you t...
by Drag
Sun Jun 12, 2022 10:54 pm
Forum: phpBB Issues
Topic: Losing login cookie constantly
Replies: 11
Views: 754

Re: Losing login cookie constantly

I know it may seem redundant, but first try deleting all of the cookies and local storage which belong to nesdev.org and nesdev.com yourself, from Firefox's settings page. After that doesn't work, one or more of your add-ons might be causing a conflict when you visit here, in which case you'd need t...
by Drag
Sun Jun 12, 2022 1:21 pm
Forum: phpBB Issues
Topic: Losing login cookie constantly
Replies: 11
Views: 754

Re: Losing login cookie constantly

That could be it. How do you visit the forums? Do you have a bookmark or a pin you click on, or do you type the URL in? Are you somehow, unintentionally, switching back and forth between http and https? I'm also a firefox user and I'm not having this issue here. My gut reaction was maybe something t...
by Drag
Sat Jun 11, 2022 3:29 pm
Forum: SNESdev
Topic: Was the SPC700's noise channel based on the 2a03's noise channel?
Replies: 16
Views: 1007

Re: Was the SPC700's noise channel based on the 2a03's noise channel?

Oh, well yes I don't believe there is any kind of separate convolution, it's just the one inherent in the operation of the LFSR, so it would be at the same period as the noise itself. At least in bsnes' code, m.noise is the LFSR itself, and it just replaces the sample output directly. No separate s...
by Drag
Fri Jun 10, 2022 11:38 pm
Forum: SNESdev
Topic: Was the SPC700's noise channel based on the 2a03's noise channel?
Replies: 16
Views: 1007

Re: Was the SPC700's noise channel based on the 2a03's noise channel?

That should already be inherent in the LFSR. "Out = Out/2 + LSFROut" is equivalent. Each step feeds a new "random" bit in on one end, and then the other bits are shifted. So, each individual bit counts once at every power of 2 magnitude as it travels through the shift register, ...
by Drag
Fri Jun 10, 2022 5:57 pm
Forum: SNESdev
Topic: Was the SPC700's noise channel based on the 2a03's noise channel?
Replies: 16
Views: 1007

Re: Was the SPC700's noise channel based on the 2a03's noise channel?

Is it actually outputting the entire contents of the LFSR all at once, with each bit at a different amplitude? Or is it just doing something like Out = Out/2 + LFSROut ? It's important to know which it's actually doing because it'll sound different at lower frequencies. Either way, the convolution i...
by Drag
Wed Jun 08, 2022 10:28 pm
Forum: SNESdev
Topic: Was the SPC700's noise channel based on the 2a03's noise channel?
Replies: 16
Views: 1007

Re: Was the SPC700's noise channel based on the 2a03's noise channel?

The C64's SID chip is the only PSG I can think of off the top of my head which uses LFSR noise but outputs more than just 1-bit for the output. SID 22 = 0 xor 5. Bit of output: 7 6 5 4 3 2 1 0 Bit of LFSR: 2 4 8 11 13 17 20 22 Other than that, yes, the most common PSGs at the time (e.g., 2a03, ay-3-...
by Drag
Wed Jun 01, 2022 4:22 pm
Forum: NESemdev
Topic: PPU Player
Replies: 4
Views: 552

Re: PPU Player

This is neat! It's funny, it seemed so natural to have a recording of register writes to store music, but I'd never thought about doing the same thing to store video. :D

I like that it has the waveform outputs as well, but that's just because I'm weird. :P