Search found 623 matches

by oRBIT2002
Mon Mar 09, 2020 1:35 am
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

Yeah I have to check all things all over again I guess. In vblank I've got a joypad-routine, scrolltext handler (with a 32 byte buffer that gets copied to PPU RAM), a function that converts a letter to tilenumber for the scrolltext. The cycles are going away fast even if there's not that much code, ...
by oRBIT2002
Mon Mar 09, 2020 12:00 am
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

Seems my NMI code sometimes "spills" into the frame that's probably causing gfx-glitches. These clockcycles are going fast, I really need more / scanline. :)
You really need to know what you're doing if you're coding stuff targeting full framerate!
Well, time for some optimizing. :)
by oRBIT2002
Sun Mar 08, 2020 5:39 am
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

I'm waiting for a sprite0 hit, and yes I'm preserving/restoring registers in the NMI
by oRBIT2002
Sat Mar 07, 2020 2:18 pm
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

Here's my joypad loop at the moment. It have it in my NMI but it doesn't seem to matter where I put it, I get screen glitches here and there. When I unroll the loop (lda $4016, sta xxx, lda $4016, sta xx etc.), the glitches are gone. ReadGamepad: ldx #1 stx $4016 dex stx $4016 txa ldy #8 ReadGamePad...
by oRBIT2002
Sat Mar 07, 2020 3:52 am
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

Thanks, think I got that working. However I'm getting gfx-glitches when reading joypad in NMI now, don't really understand why at the moment. Could reading/writing $4016 during vblank cause gfx-issues in some way?
by oRBIT2002
Fri Mar 06, 2020 1:58 pm
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

Yes I only have one split, but when I set a breakpoint in FCEUX I get a spritehit on different scanlines all the time.
by oRBIT2002
Fri Mar 06, 2020 1:55 pm
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Re: Coding a scrolltext

I'm having issues with sprite 0 hit, the flag obviously isn't cleared when read so I'm getting hits on different scanlines all the time. Any secret technique here to master this? :)
by oRBIT2002
Tue Mar 03, 2020 1:39 pm
Forum: NESdev
Topic: Coding a scrolltext
Replies: 28
Views: 8959

Coding a scrolltext

It was along time ago I tried coding something on the NES and I have never coded a splitscreen scroll but I wanted to give it a try. I'm trying to code a simple scrolltext which means I want to scroll just a tiny portion of the screen. I guess I have to time it with a sprite 0-hit (this must be done...
by oRBIT2002
Fri Aug 17, 2018 1:13 pm
Forum: NESdev
Topic: Finding JSRs in PRG ROMs
Replies: 8
Views: 3473

Re: Finding JSRs in PRG ROMs

Perhaps my old FDS-Explorer might come in handy? :) It has a built-in disassembler (perhaps not state of the art but still..)
https://www.romhacking.net/utilities/662/
or
https://nes.goondocks.se/software.php
by oRBIT2002
Sun Oct 29, 2017 11:39 am
Forum: Homebrew Projects
Topic: VS Balloon Fight -> NES project
Replies: 7
Views: 5789

Re: VS Balloon Fight -> NES project

Haven't checked it out for awhile.. I suspect there's something to do with that there's only one CPU but I am not sure..
by oRBIT2002
Tue Sep 26, 2017 9:15 am
Forum: Homebrew Projects
Topic: VS Balloon Fight -> NES project
Replies: 7
Views: 5789

Re: VS Balloon Fight -> NES project

I've put this project on hold (temporary?) but it would be nice with some help.. :)
by oRBIT2002
Mon Sep 25, 2017 9:37 am
Forum: General Stuff
Topic: Technical information, Nintendo arcadegames?
Replies: 4
Views: 1750

Re: Technical information, Nintendo arcadegames?

The only "documentation" that exists seems to be in MAME-source? I expected more, but perhaps I'm spoiled with nesdev.com. :)
by oRBIT2002
Mon Sep 25, 2017 5:11 am
Forum: General Stuff
Topic: Technical information, Nintendo arcadegames?
Replies: 4
Views: 1750

Technical information, Nintendo arcadegames?

I am a little curious what kind of hardware Nintendo used in the arcades back in the good old days. Their VS-systems I am quite familiar with but I guess they used other stuff aswell? I noticed they're starting to re-release arcade games on Switch, "Mario Bros" is coming up in just a few days but th...
by oRBIT2002
Thu May 18, 2017 12:04 pm
Forum: Homebrew Projects
Topic: VS Balloon Fight -> NES project
Replies: 7
Views: 5789

VS Balloon Fight -> NES project

I wanted to see if it was possible getting VS Balloon Fight to play on a standard NES (at least in 1-player mode). Here's how far I've come: * The game "boots". Press START to insert coins and SELECT to start the game * Currently converted to MMC1, horizontal mirroring. * Palette is currently not co...
by oRBIT2002
Wed May 17, 2017 12:49 pm
Forum: NESdev
Topic: VS Dual System question about $4016
Replies: 8
Views: 2951

Re: VS Dual System question about $4016

By your explanation (which is a bit better now btw, thanks), this shared RAM at $6000, it can only be accessed by one system at a time?
And by "asserts /IRQ on the other CPU", you mean it actually triggers an IRQ on the other CPU when writing to $4016 when bit 2 is 0?