Search found 35 matches

by timl132
Wed Aug 28, 2019 12:19 pm
Forum: NESemdev
Topic: Ice Climber in my Emulator wants to write to CHR ROM?
Replies: 7
Views: 5783

Re: Ice Climber in my Emulator wants to write to CHR ROM?

But what I think is weird is that nowhere on the internet I can find anything about this 1 byte delay. I'd expect to find at least a reference to it here but can't find it there. Anyone have like a link with all the details about this 1 byte delay? But it is documented on that page, in section 2.8....
by timl132
Wed Aug 28, 2019 9:06 am
Forum: NESemdev
Topic: Ice Climber in my Emulator wants to write to CHR ROM?
Replies: 7
Views: 5783

Re: Ice Climber in my Emulator wants to write to CHR ROM?

Yes, though there is an exception to this for $3F00-3FFF where it connects directly to the palette RAM instead with no delay. Oh okay, I'll add it as exception. It is working though! Title screen displays correctly. But what I think is weird is that nowhere on the internet I can find anything about...
by timl132
Wed Aug 28, 2019 8:24 am
Forum: NESemdev
Topic: Ice Climber in my Emulator wants to write to CHR ROM?
Replies: 7
Views: 5783

Re: Ice Climber in my Emulator wants to write to CHR ROM?

The text renders fine, but the big "Ice Climber" panel in the main menu doesn't render. Is the game by any chance trying to fetch the data for this part from CHR-ROM, like SMB does for its title screen? Some of these old games with limited PRG-ROM space use part of the CHR-ROM space for storing dat...
by timl132
Wed Aug 28, 2019 5:46 am
Forum: NESemdev
Topic: Ice Climber in my Emulator wants to write to CHR ROM?
Replies: 7
Views: 5783

Ice Climber in my Emulator wants to write to CHR ROM?

Hello, So I have been making some progress with my emulator and managed to have visual output with my PPU. Donkey kong main screen renders fine. Tests are also able to print to the screen fine. So another game I tried to render the main screen of was Ice Climber. The text renders fine, but the big "...
by timl132
Wed Jul 31, 2019 5:03 am
Forum: NESemdev
Topic: NES Emulator that logs?
Replies: 10
Views: 8101

Re: NES Emulator that logs?

Is it possible though to adjust the whitespacing in the log? Because every line in the log consists of 80% whitespace, meaning it takes up a lot more storage. That's odd. I don't recall that. Can you provide a few samples lines? Also, do you maybe know how to make a log that starts at the beginning...
by timl132
Wed Jul 31, 2019 2:40 am
Forum: NESemdev
Topic: NES Emulator that logs?
Replies: 10
Views: 8101

Re: NES Emulator that logs?

Is it possible though to adjust the whitespacing in the log? Because every line in the log consists of 80% whitespace, meaning it takes up a lot more storage. That's odd. I don't recall that. Can you provide a few samples lines? A81E 10 FC BPL $A81C A:00 X:FF Y:0E Admittetly, 80% whitespace is over...
by timl132
Tue Jul 30, 2019 1:45 pm
Forum: NESemdev
Topic: NES Emulator that logs?
Replies: 10
Views: 8101

Re: NES Emulator that logs?

So I need another NES emulator that is able to pass the tests correctly that can generate a text log for me to load into my program and compare. Does anyone know such emulator? Also, any advice on my errors is apreciated. ;) How about Nintaco ? https://nintaco.com/screenshots/11.png Nintaco is real...
by timl132
Tue Jul 30, 2019 1:25 pm
Forum: NESemdev
Topic: NES Emulator that logs?
Replies: 10
Views: 8101

Re: NES Emulator that logs?

tepples wrote:When Nintendulator crashes, what if any error message does it display?
It simply gives the generic windows crash dialog: "Nintendulator has stopped working and needs to be closed."
This is with wine on linux btw, so it's not that big of a suprise for it to be buggy. But would be nice for it to work.
by timl132
Tue Jul 30, 2019 11:11 am
Forum: NESemdev
Topic: NES Emulator that logs?
Replies: 10
Views: 8101

NES Emulator that logs?

Hi Almost finished my 6502 cpu and need to compare it to something, running nestest.nes goes *kinda* well, gives some problems with bit shifting opcodes but other than that it's fine. However the tests in instr_test_v5 all give me errors(excpet for the 01 basics test which passes for some reason). T...
by timl132
Sun Jul 28, 2019 10:47 am
Forum: NESemdev
Topic: Does the Indirect JMP instruction wrap around?
Replies: 4
Views: 5712

Re: Does the Indirect JMP instruction wrap around?

http://www.obelisk.me.uk/6502/reference.html This one mentions it very clearly in the section about the JMP instruction: NB: An original 6502 has does not correctly fetch the target address if the indirect vector falls on a page boundary (e.g. $xxFF where xx is any value from $00 to $FF). In this c...
by timl132
Sun Jul 28, 2019 8:29 am
Forum: NESemdev
Topic: Does the Indirect JMP instruction wrap around?
Replies: 4
Views: 5712

Re: Does the Indirect JMP instruction wrap around?

Yes, that's how JMP indirect works. I won't go through the trouble of looking for references now, but this is not a secret or an obscure behaviour by any means, it's mentioned fairly frequently in documents about the 6502. Maybe it's not mentioned along with the JMP instruction itself, but there's ...
by timl132
Sun Jul 28, 2019 7:33 am
Forum: NESemdev
Topic: Does the Indirect JMP instruction wrap around?
Replies: 4
Views: 5712

Does the Indirect JMP instruction wrap around?

Hello, I have a bug in my CPU where JMP Indirect reads the wrong address. I used the Nintendulator debugger to find out what it's supposed to be, and I think that the Indirect JMP instruction needs to wrap around at the end of a page. The instruction is JMP($02FF) which is supposed to end up jumping...
by timl132
Fri Jul 26, 2019 6:30 am
Forum: NESemdev
Topic: Fake microinstructions to implement 6502 cpu emulator?
Replies: 4
Views: 6030

Re: Fake microinstructions to implement 6502 cpu emulator?

I really love that video, but honestly, this approach is just about optimizing for "simple" code, and probably not widely applicable in any other way than that. In emulators it's common to have shared code between instructions, but not executed by a matrix like that. At least, not to that extent. I...
by timl132
Thu Jul 25, 2019 7:08 am
Forum: NESemdev
Topic: Fake microinstructions to implement 6502 cpu emulator?
Replies: 4
Views: 6030

Fake microinstructions to implement 6502 cpu emulator?

Hi, Dunno if this is appropriate for this subforum, but I came across this video where a guy programmed a NES emulator in a 1000 lines of code. Because it was a youtube video he had to make sure to not make it too long, so he made a lookup table for CPU "microinstructions". What I mean is he made a ...
by timl132
Thu Jul 25, 2019 12:11 am
Forum: NESemdev
Topic: I need more info about the 6502 CPU instruction set.
Replies: 36
Views: 18771

Re: I need more info about the 6502 CPU instruction set.

Okay, this behaviour needs to stop. Right now. Situations like this make me wish I hadn't rescinded my admin flag some years ago. You've now had 4 separate people tell you to read resources, and all of us giving you links/advice on what to read; one was extremely nice in referring to it as "homewor...