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PostPosted: Wed Aug 10, 2005 9:38 am 
My NES emulator is working fairly well for the most part. However, I'm at a point where there are several issues that I don't know how to solve. I thought maybe some of you might have come across these and could offer suggestions. I have sprite zero (not perfect) in place, pass all of the CPU tests in Nestress, and most mapper 0 - 4, 7, 9 games work flawlessly (except the timing tough ones like rad racer, marble madness, battletoads, etc...)

0) Topgun. The dashboard flickers a lot when taking off. It is stable in flight.

1) Puchout: there is a white box over Glass Joe's face.

2) Air Fortress: The star sprites on the first rendered screen with the spaceship are messed up. It seems to be pulling tiles from the wrong pattern table.

3) Kung Fu. Does this game require precice timing? The background scrolls incorrectly making the main character have no legs when he walks.

4) Ice Hockey. On the title screen, there is a grabage scroll under the title. It's supposed to be a bunch of characters. This is between the Ice Hockey title and the "1 player start" text

5) Blades of Steel: In the demo after the title, the referee flickers, and no characters come out. There are also grabage sprites randomlly placed on the screen.

6) Zelda 2: In the overworld, pressing left or right is not responsive. Link moves....pauses for 2 seconds....moves...and so on. In the battles, left and right movement is fluid.

7) Excitebike: Once a race has started, the motorcycle/rider flicker a lot. Then after 10 seconds or so down the track, the race (not the game) resets.

8) What mapper is "The Goonies (J).nes"

9) Legend of Zelda: When I press start, the item screen scrolls down, nut then immediatly the screen asking to "continue, save, retry" apears. This makes it so I have to reset the game.

10) SMB3: When mario jumps up and pulls down the SMB3 title on the initial game intro, the title doesn't "shake" when it gets to the bottom. It just flickers for a few seconds instead.

11) Star Voyager hangs after the character gets into the spaceship in the hangar.

12) Duck Tales 1 + 2, Ms Pacman, and more won't work correctl (if at all) unless I don't clear 2002.D7 after a read.

13) Games that hang before displaying any graphics (Hoops, Jordon Verses Byrd, RBI Baseball). This happens whether I clear 2002.7 after a read or not.

14) Games that crash (invalid opcode) within seconds or starting: Who Framed Roger Rabbit (U), TMNT 3 (U), Cobra Triangle (U), Wheel of Fortune Family Edition (U), Wheel of Fortune (U).

The crashes are not mapper related issues (I assume) because all the other games work fine. In fact TMNT crashes before ever writing to a mapper register. This must be a core bug, but I have no idea how to go about tracking these down.

Thanks in advance.


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PostPosted: Wed Aug 10, 2005 10:31 am 
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The Goonies ROM that I have is called "Goonies, The (J).nes" It uses mapper 87 according to Nintendulator.


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PostPosted: Wed Aug 10, 2005 12:20 pm 
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Emugalaxy wrote:
My NES emulator is working fairly well for the most part. However, I'm at a point where there are several issues that I don't know how to solve. I thought maybe some of you might have come across these and could offer suggestions. I have sprite zero (not perfect) in place, pass all of the CPU tests in Nestress, and most mapper 0 - 4, 7, 9 games work flawlessly (except the timing tough ones like rad racer, marble madness, battletoads, etc...)

0) Topgun. The dashboard flickers a lot when taking off. It is stable in flight.

It shouldn't flicker.

Emugalaxy wrote:
1) Puchout: there is a white box over Glass Joe's face.

2) Air Fortress: The star sprites on the first rendered screen with the spaceship are messed up. It seems to be pulling tiles from the wrong pattern table.

3) Kung Fu. Does this game require precice timing? The background scrolls incorrectly making the main character have no legs when he walks.

It does not need precise timing. Should be fairly easy to get this one working.

Emugalaxy wrote:
4) Ice Hockey. On the title screen, there is a grabage scroll under the title. It's supposed to be a bunch of characters. This is between the Ice Hockey title and the "1 player start" text

Up to here I'd bet your emu's problem is not having a correct scrolling scheme. Have you read Loopys scrolling texts? You can find'em on the NesDev's main page. You can also check older posts on this board, you'll surely find useful info on how to get it working.

Emugalaxy wrote:
5) Blades of Steel: In the demo after the title, the referee flickers, and no characters come out. There are also grabage sprites randomlly placed on the screen.

I dunno what precission this game requires, but should be too high. I guess this has something to do with not having sprites properly emulated (may it be related with regs r/w too?)

Emugalaxy wrote:
6) Zelda 2: In the overworld, pressing left or right is not responsive. Link moves....pauses for 2 seconds....moves...and so on. In the battles, left and right movement is fluid.

7) Excitebike: Once a race has started, the motorcycle/rider flicker a lot. Then after 10 seconds or so down the track, the race (not the game) resets.

Huh.. rider shouldn't flicker, though the strangest thing here is the game being reset..

Emugalaxy wrote:
8) What mapper is "The Goonies (J).nes"

9) Legend of Zelda: When I press start, the item screen scrolls down, nut then immediatly the screen asking to "continue, save, retry" apears. This makes it so I have to reset the game.

Huh.. you know, that isn't the expected behaviour. Have you checked your CPU core using Kevin Horton's nestest.nes demo?

Emugalaxy wrote:
10) SMB3: When mario jumps up and pulls down the SMB3 title on the initial game intro, the title doesn't "shake" when it gets to the bottom. It just flickers for a few seconds instead.

11) Star Voyager hangs after the character gets into the spaceship in the hangar.

12) Duck Tales 1 + 2, Ms Pacman, and more won't work correctl (if at all) unless I don't clear 2002.D7 after a read.

13) Games that hang before displaying any graphics (Hoops, Jordon Verses Byrd, RBI Baseball). This happens whether I clear 2002.7 after a read or not.

Again, check your CPU core using the demo I mentioned some lines above.

Emugalaxy wrote:
14) Games that crash (invalid opcode) within seconds or starting: Who Framed Roger Rabbit (U), TMNT 3 (U), Cobra Triangle (U), Wheel of Fortune Family Edition (U), Wheel of Fortune (U).

Not sure about these ones but, if they're not bad dumps, they should work flawlessly..

Emugalaxy wrote:
The crashes are not mapper related issues (I assume) because all the other games work fine. In fact TMNT crashes before ever writing to a mapper register. This must be a core bug, but I have no idea how to go about tracking these down.

My advice would be to check if 2005/6/7 reads & writes are being handled correctly (Loopy's docs are quite helpful), plus revising your sprite #0 hit handler. Those usually solve the kind of problems you're having.

Emugalaxy wrote:
Thanks in advance.

You're welcome. :wink:


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PostPosted: Wed Aug 10, 2005 1:01 pm 
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resets, bad opcodes, and other odd behaviors are almost ALWAYS caused by either improper mapper emulation or CPU bugs. Since Excitebike is mapper 0, I'm betting on the latter.

Go over your CPU emulator with a fine-tooth comb. If you have some sort of tracer or something make logs and look over them, verifying the CPu is flowing as it should. This will be easier in the games which are hitting bad opcodes because it'll be easy to see exactly where the CPU has gone off track.

Fix your CPU bug(s) and most of these problems will almost certainly disappear.


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PostPosted: Wed Aug 10, 2005 1:40 pm 
I created logs for the games that crashed. The problem is that 1000's of instructions execute making it nearly impossible to trace. It would take forever examining the logic. Any suggestions?


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PostPosted: Wed Aug 10, 2005 1:52 pm 
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Start following the log from the bad opcode and work back from there.


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PostPosted: Thu Aug 11, 2005 10:36 am 
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You can also modify a known working emulator to output log info similar to what your emulator outputs. Then, you can do a diff of the two output logs and see where things go differently.


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PostPosted: Mon Aug 29, 2005 10:48 pm 
i was looking for Kevin Horton's nestest.nes demo and could not find it. anyone know where?

and i was trying to get nestress to work, but i only get a grey screen. but still early testing right now.

any other test roms that are good ? maybe cpu and ppu ?

thanks matt.

and i still cannot log in....


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PostPosted: Tue Aug 30, 2005 5:55 am 
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Anonymous wrote:
i was looking for Kevin Horton's nestest.nes demo and could not find it. anyone know where?


I found a demo by the same name here:

http://tripoint.org/kevtris/mappers/incoming/


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PostPosted: Tue Aug 30, 2005 8:37 am 
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Anonymous wrote:
and i still cannot log in....


Which username? If it's mattmatteh, it's already active. Try the 'forgot my password' and see if it emails that you (I haven't got any bounced msgs lately).


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 Post subject: nestest and log in
PostPosted: Tue Aug 30, 2005 10:52 am 
thanks i got nestest.

memblers,

still can not log in, and i started a post here;

http://nesdev.com/bbs/viewtopi ... =4173#4173

thought it should be moved or sent to you?

matt


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PostPosted: Tue Oct 25, 2005 2:30 pm 
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I can't find the source code to nestest anywhere.
Can somebody tell me where I can find it?

Have trouble running it in my emu.


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