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Just a quick word about the 6502' interrupts. If an interrupt happens during an opcode (lets say cycle 3 of 6 ASL ZPX) is the opcode finished before the interrupt is executed? Also apparently the BRK opcode's breakpoint is ignored if the occurs, doe anyone have any more information regarding this?

Thanks, just to confirm; 1st Write = 1 2nd Write = 1 3rd Write = 1 4th Write = 0 5th Write = 1 Would mean: MSB-10111-LSB? You see the trouble that I am having is on Zelda. It writes a 7 then a 5 to register 3. The first write is ok but on the second switch I get the illegal opcode error. Does Zelda ...

Since Battletoads is an AOROM (mapper 7) it is no wonder that it requires that much timing. Anes, is your emulator precise?

Exactly the same things happens on my emulator. When the toad drops before he gets to the ground the game just freezes. I think that it is to do with my sprite 0 hit detection as I am still getting an error in NEStress.

Maybe the game requires precise timing?

How is data entered into the 5-bit array?

Like this:

1st Write == 1

00001 <-- LSB

or:

1st Write == 1

--> MSB 10000

Also is the LSB of the data written the actual value that goes into the array? Or is it if the data is equal to anything other than 0?

After doing some testing, FCE Ultra is the only emulator that seems to get an ok from NEStress, even though there seems to be no issues with other emulators and their hit detection (i.e. games that use it play just fine). Let's just clarify one thing. If a sprite's pixel (i.e. 1-3 in the palette ind...

Because WedNESday renders a scanline and THEN goes back and draws the sprites I suppose tha this may have an effect on certain games. Would it explain why NEStress gives me an error then?

Yeah, I am already doing that, but for some unknown reason collision detection is a bit buggy. Games that seems to use a bg #0 sprite are ok but the other way around seems to fail. I'll keep trying.

I am finding it hard to get my Sprite #0 hit detection to work. Here are the circumstances that I set bit 6 of 2002 under; if( Sprite == 0 && Pixel != Transparent ) SetFlag; If the collision is behind the background then I have no problem. But if the sprite is in the foreground (like the 2nd...

Thanks for letting me know. For the time being i'll stick with my scanline engine, just so I can play some of the more basic ROMs. But in the future I will write an accurate PPU renderer. The real point that I am making is that I never intended to make my NES emulator 100% accurate, I just did it fo...

I am currently emulating accurate CPU timing so that may help. What kind of effect does Final Fantasy etc. use that may effect my emulator?

WedNESday can do both vertical and horizontal scrolling including split screen scrolling no problem. Also, WedNESday ignores the PPU documents (341 ppu cc etc.) and just renders the scanline normally (i.e. it just fetches 1 tile every 8 pixels and renders it). I know that some of you may think that ...

WedNESday draws the screen (and has no issues with priority or anything else) by drawing the scanline and then going back and drawing the sprites on a pixel for pixel basis. When it has found 8 sprites it then stops. So far this method is very simple and proves very accurate.

Thanks for all of the replies but I have managed to solve the problem now.

Btw, WedNESday draws the screen on a scanline for scanline basis.

Thanks everyone, now I have it sorted (it was my own fault lol)...