Search found 4242 matches

by Dwedit
Sat Feb 08, 2020 9:17 pm
Forum: NESemdev
Topic: agnes - single C header NES emulation library
Replies: 11
Views: 8907

Re: agnes - single C header NES emulation library

If raster effects are causing problems, you need a different way to think about whole-screen rendering. After a frame runs, you can collect information for each scanline: (possibly sample this information at the middle of each scanline) * X Scroll * Y Scroll * PPU Control * PPU Mask * 8 selected CHR...
by Dwedit
Fri Jan 31, 2020 9:40 am
Forum: NESdev
Topic: New NES Homebrew Demo (Wart Worm Wingding)
Replies: 6
Views: 754

Re: New NES Homebrew Demo (Wart Worm Wingding)

Unfortunately, this is a copypasta from /r/nes/comments/ec8kg1/new_nes_homebrew_demo_wart_worm_wingding/

And "davidbrok5" is not the creator of the game, that would be "jvanderhoef".

We have a spam post here, well-disguised as stealing credit for a game.
by Dwedit
Sat Jan 25, 2020 11:06 am
Forum: NESdev
Topic: NES-001 PPU compatible questionan issue after rgb mod
Replies: 16
Views: 2056

Re: NES-001 PPU compatible questionan issue after rgb mod

Is the exact text "PUST STEVT"? Improperly connected address lines cause the wrong tile to be fetched. I don't know any combination of address line failures that would produce that exact message.
by Dwedit
Thu Jan 23, 2020 10:53 pm
Forum: NESdev
Topic: NES-001 PPU compatible questionan issue after rgb mod
Replies: 16
Views: 2056

Re: NES-001 PPU compatible questionan issue after rgb mod

Maybe try using a voltmeter or oscilloscope to see if the pins have the correct signal levels. Around 11:55 in this video, https://www.youtube.com/watch?v=N8YVX75Qr-0 (Apple IIc Repair), he uses an oscilloscope to diagnose the address and data lines. At about 14:22, there's a bad data connection see...
by Dwedit
Thu Jan 23, 2020 10:51 am
Forum: NESdev
Topic: NES-001 PPU compatible questionan issue after rgb mod
Replies: 16
Views: 2056

Re: NES-001 PPU compatible questionan issue after rgb mod

Getting properly formed numbers tells you a lot of about the status of the PPU. In order to get a properly formed number, the data bus must be connected correctly. Any improperly connected bit will show up as a vertical line on the screen. It also tells you that the low 3 bits of the address bus are...
by Dwedit
Thu Jan 09, 2020 4:24 pm
Forum: NESdev
Topic: Auditing your own code.
Replies: 9
Views: 1814

Re: Auditing your own code.

Generally not a problem with your own assembly code, since you had to make everything. You can read through the listing file if you need to see if anything is out of place.
by Dwedit
Wed Jan 08, 2020 4:31 pm
Forum: NESemdev
Topic: Kid Dracula from Castlevania Anniversary Collection - incompatibility with emulators
Replies: 8
Views: 1234

Re: Kid Dracula from Castlevania Anniversary Collection - incompatibility with emulators

Kid Dracula should be 384kb, not 256kb? Probably an underdump of some kind.
by Dwedit
Tue Jan 07, 2020 11:27 am
Forum: NESemdev
Topic: Some pipes lead to weird non-rooms in Super Mario Bros.
Replies: 15
Views: 2772

Re: Some pipes lead to weird non-rooms in Super Mario Bros.

I think the ROM Singles are mapper 0, so you can just run those for now.
Note that they test unofficial instructions too, so if you're not trying for those at the moment, you can ignore errors regarding them.
by Dwedit
Mon Jan 06, 2020 12:42 pm
Forum: NESemdev
Topic: Some pipes lead to weird non-rooms in Super Mario Bros.
Replies: 15
Views: 2772

Re: Some pipes lead to weird non-rooms in Super Mario Bros.

Start with the basics.

First confirm that you pass CPU tests.

Then confirm that the memory map is correct, and that when you read a byte, the correct byte is read, including page crossing and zeropage wrapping.
by Dwedit
Fri Jan 03, 2020 11:37 am
Forum: NESemdev
Topic: Some pipes lead to weird non-rooms in Super Mario Bros.
Replies: 15
Views: 2772

Re: Some pipes lead to weird non-rooms in Super Mario Bros.

As fas as I know, it's not level data in CHR ROM, it's the title screen.
by Dwedit
Fri Jan 03, 2020 10:32 am
Forum: General Stuff
Topic: Multi-pass assembler questions
Replies: 7
Views: 1725

Re: Multi-pass assembler questions

You can keep a symbol dependency tree if you need to. Declare that A depends on B and C, and B depends on D, etc. Much easier to do this in a language with easy hashtables.
by Dwedit
Sun Dec 29, 2019 12:09 pm
Forum: NESdev
Topic: Proper way to animate tiles with an NROM
Replies: 7
Views: 2107

Re: Proper way to animate tiles with an NROM

You'd probably want to create some kind of Packet system for playing back your upcoming PPU changes. Example of how to make a VRAM writing system: * Reserve a big block of memory, maybe 128 bytes large. (Maybe use the stack page 0x100) * Write formatted data like this: High Byte of PPU Address, Low ...
by Dwedit
Tue Dec 24, 2019 9:58 am
Forum: phpBB Issues
Topic: Posts per page?
Replies: 0
Views: 1404

Posts per page?

I was wondering if there was any way to increase the posts per page up to something really big, so I don't have to look at separate pages of a long thread?
by Dwedit
Tue Dec 24, 2019 9:45 am
Forum: NESdev
Topic: Random glitchy line in Super Mario Bros. on real hardware?
Replies: 94
Views: 66500

Re: Random glitchy line in Super Mario Bros. on real hardware?

It's still unclear exactly what the timing is for the glitch, and what the actual behavior is. It seems to happen when "T" is changed for any reason, such as $2000 writes, or scrolling/VRAM address register writes. It seems to affect the value that is written to "V" without affecting the value of "T...