Search found 18 matches

by Drilian
Mon Aug 12, 2019 11:05 pm
Forum: NESemdev
Topic: Help with APU Triangle emulation bug?
Replies: 7
Views: 6560

Re: Help with APU Triangle emulation bug?

Oh awesome, thanks for the clarification! That all makes sense and, I think, jives with how I have everything implemented. $4008 doesn't SET the reload flag but it can allow a reload to proceed if one was waiting.

Thanks again!
by Drilian
Sun Aug 11, 2019 11:59 pm
Forum: NESemdev
Topic: Help with APU Triangle emulation bug?
Replies: 7
Views: 6560

Re: Help with APU Triangle emulation bug?

So I think I found the problem! In your write_a function for linear counter, you're setting should_reload to be true. However, I have a comment in my code that says "nesdev wiki says that this sets the reload flag but that seems to be untrue!" (which, incidentally, I forgot about and meant to bring ...
by Drilian
Fri Jul 26, 2019 3:00 am
Forum: NESemdev
Topic: Castlevania 2 triangle linear counter
Replies: 4
Views: 6627

Re: Castlevania 2 triangle linear counter

Oh thanks! It’s nice to have a recording of the game actually from an NES, I could not find one to save my life! Good to know that the behavior I’m seeing is, in fact, that of a real system (at least in this case) The first video was definitely nsf playback, I only linked it as an example of the inc...
by Drilian
Thu Jul 25, 2019 6:16 pm
Forum: NESemdev
Topic: Castlevania 2 triangle linear counter
Replies: 4
Views: 6627

Castlevania 2 triangle linear counter

(First off, hello it's been a long while since I posted here, and it's wild to see many of the same people still rolling along! Decided to pick up my NES emulator again after 10 years because I needed something to poke at in my spare time, and this is apparently the type of thing that I like to do f...
by Drilian
Sat Feb 09, 2008 11:09 pm
Forum: NESemdev
Topic: SMB status bar Flicker
Replies: 1
Views: 2162

SMB status bar Flicker

I'm back! Opted to resurrect my emulator project after...years. Anyway, when there is a lot of stuff going on in a SMB level (easiest to repro in 8-1 by throwing some fireballs with 3 goombas and a green turtle on-screen), I see the actual status bar flicker off to the side. Investigation has shown ...
by Drilian
Wed May 10, 2006 4:40 pm
Forum: NESemdev
Topic: more sprite wiki questions...
Replies: 1
Views: 1618

The sprites that are being evaluated during a scanline (via the sprite access information) are the sprites that will be displayed on the NEXT scanline. So while it's rendering the current scanline (and any sprites that were found during the previous line) it's finding the sprites for the next scanli...
by Drilian
Tue Jul 26, 2005 11:46 am
Forum: NESemdev
Topic: Castlevania IIIe issues
Replies: 38
Views: 17749

I think the worst thing about Nesticle is that, due to its extreme popularity, people would hack ROMs to run correctly in it, and thus ruin them when more accurate emulators eventually started coming out. I can't remember any game specifically, but I know there were changes made to ROMs for the expr...
by Drilian
Wed Feb 09, 2005 3:04 pm
Forum: NESemdev
Topic: What are the Unanswered Questions?
Replies: 5
Views: 5694

What are the Unanswered Questions?

So, what are the current "unknowns" in terms of how the base NES hardware works with respect to emulation? (base hardware being non-mapper related) The one I know if is how sprite memory is accessed during rendering. My goal is to (if possible) write some test ROMS that test these unknowns and hopef...
by Drilian
Tue Feb 01, 2005 8:38 am
Forum: NESemdev
Topic: MMC1, 32k bankswitching... Which games?
Replies: 1
Views: 3889

Dragon Warrior 3 and Dragon Warrior 4 are the only two US games that I know of that have 32K of PRG banks with the MMC1. I'm betting there are more in Japan.
by Drilian
Mon Jan 31, 2005 8:28 pm
Forum: NESemdev
Topic: Sprite memory access during rendering
Replies: 0
Views: 4535

Sprite memory access during rendering

I was under the impression that BT's doc is inaccurate with relation to how sprite memory is accessed during rendering (and how writing/reading 2003 or 2004 [when applicable] affects it). Does anyone have any accurate info on this? Currently, my emulator reads one byte of sprite memory (starting wit...
by Drilian
Thu Jan 27, 2005 3:09 pm
Forum: NESemdev
Topic: Castlevania IIIe issues
Replies: 38
Views: 17749

Ah, I wasn't looking far enough down the road in Rad Racer 2 :)
by Drilian
Thu Jan 27, 2005 1:48 pm
Forum: NESemdev
Topic: Castlevania IIIe issues
Replies: 38
Views: 17749

I see glitches in Rad Racer (1) when you go off to the left in my emulator, but nothing in RR2.

And there's no harm in this going off topic, I've solved my problems (thanks again for the help!) :)
by Drilian
Thu Jan 27, 2005 1:21 pm
Forum: NESemdev
Topic: Background/sprite clipping
Replies: 4
Views: 5101

Okay, good, I wasn't giving out incorrect info :)

What I meant was, I don't actually have an NES. Sad, but true. All I have is a laptop, a Playstation controller with a USB adapter, an SVideo cable, and an emulator currently in development.
by Drilian
Thu Jan 27, 2005 8:15 am
Forum: NESemdev
Topic: Background/sprite clipping
Replies: 4
Views: 5101

The 8 pixels on the side of the screen? I'm under the impression that the real NES draws the background color instead of just black. But I have absolutely nothing to back that up :)
by Drilian
Wed Jan 26, 2005 8:00 pm
Forum: NESemdev
Topic: Castlevania IIIe issues
Replies: 38
Views: 17749

Not quite sure what you mean, Fx3. Hyde's referring to my comment about Battletoads, where level 2 would lock up if the timing were off. He'd been helping me try to solve it back on the old boards. Yeah, I did change the V counters to cycle 251 to get it working, I remember now (it's been a while). ...