Search found 23 matches

by lukexor
Tue Jun 21, 2022 8:58 pm
Forum: NESemdev
Topic: Difficulty Running Fogleman GO NES Emulator on Ubuntu 16.04
Replies: 1
Views: 581

Re: Difficulty Running Fogleman GO NES Emulator on Ubuntu 16.04

I haven't tried using Foglemans emulator in a long time, but I did get it working on macOS so it seems like it should run in Ubuntu. I used it as a starting point for TetaNES as well though while it was great for starting, there is a lot missing and it's not very well documented. There are lots of o...
by lukexor
Fri Nov 08, 2019 12:34 pm
Forum: NESemdev
Topic: Sprite 0 Hit Test ROMs
Replies: 10
Views: 19389

Re: Sprite 0 Hit Test ROMs

I know this post is rather old, but I'm trying to shore up my final few test roms I'm not passing and I found some differences between the various Sprite 0 hit test roms on the wiki. RustyNES can pass all the tests from the original zip in this post (The one that unzips to sprite_hit_tests_2005.10.0...
by lukexor
Tue Nov 05, 2019 1:42 am
Forum: NESemdev
Topic: MMC5 EXRAM
Replies: 2
Views: 7323

Re: MMC5 EXRAM

I figured it out finally! I was missing a key bit from natt on this post: 1. PPU fetches an NT byte; that is, (addr >= 0x2000 && (addr & 0x3ff) < 0x3c0) Return the NT fetched byte as requested from whatever nametable is in context. Let N = addr & 0x3ff; that will be your index into E...
by lukexor
Mon Nov 04, 2019 11:40 pm
Forum: NESemdev
Topic: MMC5 EXRAM
Replies: 2
Views: 7323

Re: MMC5 EXRAM

Well a slight update.

I managed to get the scrolling intro text to work. I feel sort of silly, my multiplier wasn't working properly.

Some screenshots. BG tiles are still broken, but working on tracking it down.
Screen Shot 2019-11-04 at 22.35.49.png
Screen Shot 2019-11-04 at 22.39.09.png
by lukexor
Fri Nov 01, 2019 11:29 am
Forum: NESemdev
Topic: MMC5 EXRAM
Replies: 2
Views: 7323

MMC5 EXRAM

So I've been working on finishing up my MMC5 implementation for several days and I can't seem to grasp how EXRAM fully works. I can play Castlevania III all the way through and even the water rising after the boss in stage 06 fills up with water like it's supposed to. Uncharted Waters loads and seem...
by lukexor
Wed Oct 30, 2019 11:45 pm
Forum: NESemdev
Topic: Academic question regarding bank switching hardware (MMC5)
Replies: 3
Views: 5959

Academic question regarding bank switching hardware (MMC5)

While I have some MMC5 functionality working (Castlevania III works fine for a full play through), I've been struggling to get other games to work and while I believe the issues lie with improper ExRAM functionality mostly, I got to thinking about how I've been doing bank switching. For most other m...
by lukexor
Sat Oct 26, 2019 9:39 am
Forum: NESemdev
Topic: scanline.nes Test Rom
Replies: 6
Views: 6973

Re: scanline.nes Test Rom

Testing OpenEMU with the Nestopia core results in some flicker of the stars in the top section, and a slight flicker (smaller than mine) of the dotted bars in the bottom section.
by lukexor
Fri Oct 25, 2019 6:39 pm
Forum: NESemdev
Topic: scanline.nes Test Rom
Replies: 6
Views: 6973

Re: scanline.nes Test Rom

Oh perfect! thank you. Guess I didn't scrounge hard enough through the search pages. Good to know, but interesting that neither OpenEMU or FCEUX have the flicker.
by lukexor
Fri Oct 25, 2019 6:21 pm
Forum: NESemdev
Topic: scanline.nes Test Rom
Replies: 6
Views: 6973

scanline.nes Test Rom

I've looked around for a good while trying to find anyone else who may have explained how this rom works in more detail. It's the one made by Quietust to test basic PPU emulation. I used to have it working fine before I implemented cycle accuracy, and now I have some slight shimmy on the bottom two ...
by lukexor
Fri Oct 25, 2019 8:00 am
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

Yeah I know, I just meant from an emulation read/write perspective the way I'm doing it there are only actually 5 read/writes from/to memory which include pushing the current PC/flags to the stack and reading the interrupt vectors so I'm faking two additional reads for the first two cycles. Things s...
by lukexor
Thu Oct 24, 2019 5:26 pm
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

Got it!! Silly me. When I converted over to be cycle accurate, I forgot that pushing/popping from the stack for IRQ/NMI also ran the PPU to catch up and instead I was running 7 cycles to catch up, which was 5 cycles too many (since IRQ and NMI performs 5 read/writes). Changing it to do 2 wait cycles...
by lukexor
Thu Oct 24, 2019 3:37 pm
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

I used my Nametable debugging and compared to FCEUX and it seems to match - it flips the top two nametables to each half of the road in front of you at several scanlines between 130 and 150 and it seems to toggle back and forth between the road and the underlying ground color. I'm sure this has to d...
by lukexor
Thu Oct 24, 2019 3:31 pm
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

Okay, ill explore that but it didn't seem to work when I allowed palette reads to clock it but I thought you said palettes weren't attached to the bus? Yes - I have FourScreen mirroring enabled. As I mentioned, these all worked fine before I changed my catch-up to be per cycle instead of per instruc...
by lukexor
Thu Oct 24, 2019 3:19 pm
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

A little update. I fixed Mickey's jittering scanline issue by implementing this bit: Here's how it works as I understand it: If background patterns are at $0000 and sprite patterns are at $1000, PA12 will rise eight times, at x=260, 268, ..., 316. It is believed that the MMC3's scanline counter igno...
by lukexor
Thu Oct 24, 2019 2:46 pm
Forum: NESemdev
Topic: MMC3 IRQ Specifics
Replies: 15
Views: 11648

Re: MMC3 IRQ Specifics

Okay, that helps! There doesn't happen to be any specific test roms for the MC-ACC? All I can find is that the difference is that it triggers on falling edges of A12 (1 -> 0)? However, I'm confused because http://forums.nesdev.com/viewtopic.php?p=116691#p116691 says it should make MC-ACC IRQ occur 4...