Baseball Stars 2: 2-player credits bug

Neo Alec

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Can anyone else confirm this bug on their system? Please post your bios and cart type (AES/MVS/multicart)

While running Baseball Stars 2 in MVS USA mode, the game requires 2 credits inserted in order to select the 2-player mode. But if at least one of those credits (one or both) is on the 2-player side, then the game only subtracts 1 credit when the game is started. If both credits are on the 1-player side, then it costs 2 credits to start the 2-player game.

This happened with my Unibios 4.0 with original MVS cart.
 

Neo Alec

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Bump. I know this is not an interesting bug. On its own, it's not worth mentioning in my next video. However, it is tangentially related to an old item I do want to show in the video.

If you have the game or a flash cart and have a moment, please help confirm. I'd appreciate it.
 

city41

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I see this happening in MAME. Possibly related to having two separate credit pools in USA mode but only one credit pool in Euro or Jpn mode.
 

city41

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This is pretty interesting. You also can't play on the P2 side in a single player game in KOF94 in JPN MVS or Euro MVS, but you can in USA.

I guess that makes sense as versus cabs aren't really a thing in Japan? I was surprised it's true for Europe too, but I know even less about their cabs.

The hardware dips page says
  • Switch 2: Number of coin chutes (1 or 2 Euro & Japan, 2 or 4 on USA)

But when I turn that dip on, the service menu screen says the chutes are in VS-MODE, but nothing acts differently for coining up or starting a game that I can see.

Anyway, I didn't mean to derail the thread but it feels like this difference in how USA handles credits is related to what bstars2 is doing.
 

prof

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Alec, I just saw a 2 slot repair video where the guy addressed something similar to what you're asking about. Watch at the 34 minute mark. If you're experiencing the same thing, it sounds like it can be adjusted in the "test menu."

 

Pro_Gear

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I tested this with my MVS BS2 cart on 4.0 UniBIOS set to USA- I can confirm this behavior with one additional condition to your original findings:

In a situation where both 1P and 2P sides have entered 1 credit, if you use the 1P start button to begin, it only costs 1 credit for both players like you stated.
If you use the 2P start to begin it will cost 2 credits for the 2 player game.
 

Neo Alec

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This is pretty interesting. You also can't play on the P2 side in a single player game in KOF94 in JPN MVS or Euro MVS, but you can in USA.

I guess that makes sense as versus cabs aren't really a thing in Japan? I was surprised it's true for Europe too, but I know even less about their cabs.

The hardware dips page says
  • Switch 2: Number of coin chutes (1 or 2 Euro & Japan, 2 or 4 on USA)

But when I turn that dip on, the service menu screen says the chutes are in VS-MODE, but nothing acts differently for coining up or starting a game that I can see.

Anyway, I didn't mean to derail the thread but it feels like this difference in how USA handles credits is related to what bstars2 is doing.
Yeah, that's why I specified the region. The USA region is the only one I'm really concerned with for the sake of the video. You'll see why.

Alec, I just saw a 2 slot repair video where the guy addressed something similar to what you're asking about. Watch at the 34 minute mark. If you're experiencing the same thing, it sounds like it can be adjusted in the "test menu."

Yeah, that's hard dip switch 2 @city41 mentioned.

I tested this with my MVS BS2 cart on 4.0 UniBIOS set to USA- I can confirm this behavior with one additional condition to your original findings:

In a situation where both 1P and 2P sides have entered 1 credit, if you use the 1P start button to begin, it only costs 1 credit for both players like you stated.
If you use the 2P start to begin it will cost 2 credits for the 2 player game.
Wow, you're right. I can confirm. That's bizarre. Thanks for checking this for me. I'm starting to not want to go down this rabbit hole at all.
 

city41

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Wow, you're right. I can confirm. That's bizarre. Thanks for checking this for me. I'm starting to not want to go down this rabbit hole at all
According to the dev wiki, it's up to the bios to handle decrementing credits. So probably a bug in the US bios and at that point I turned around myself. I think debugging the bios would be a tedious time.
 

Neo Alec

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According to the dev wiki, it's up to the bios to handle decrementing credits. So probably a bug in the US bios and at that point I turned around myself. I think debugging the bios would be a tedious time.
So I was wondering if other games are impacted. I believe your standard fighters and Metal Slug games don't have this problem. I might try 2020 Super Baseball.

The thing about Baseball Stars 2 is you select 2-player from a menu rather than simply coining up and joining with start. The fact that the second credit is only deducted when the game starts make me think it's a bug in the game.
 

Neo Alec

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2020 Super Baseball seems to work completely differently. It requires a credit in each side to select 2-player mode. And if you already hit start before the credits are added, you're stuck playing 1-player. It won't even let you join during the game.
 

city41

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Addresses 10fdb0-3 are BIOS_CREDIT_DEC for each player
Credit decrement value for each player (1, 2, 3, 4) when calling CREDIT DOWN.

CREDIT_DOWN is a routine in the bios that the game calls to decrement credits. The game first sets up BIOS_CREDIT_DEC values depending on who is playing and how much the game should cost, then the bios decrements the credits.

So now I'm thinking this is a bug in BS2 itself. It seems to be calling this routine incorrectly in some situations.
 

Neo Alec

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Addresses 10fdb0-3 are BIOS_CREDIT_DEC for each player


CREDIT_DOWN is a routine in the bios that the game calls to decrement credits. The game first sets up BIOS_CREDIT_DEC values depending on who is playing and how much the game should cost, then the bios decrements the credits.

So now I'm thinking this is a bug in BS2 itself. It seems to be calling this routine incorrectly in some situations.
Yeah, that's what I'm thinking. There's a CREDIT_DOWN that's getting missed depending on how you start the game. In situations where it costs 2 credits to start, it doesn't take them both at once. It takes one when start is pressed, and second when the 2-player mode is selected. That second one doesn't always happen.
 

Neo Alec

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I think the bug is that the second credit (the one where you select the mode) always gets deducted from the 1-player side (BIOS_CREDIT_DEC1 ( $10FDB0)). If there aren't any credits there, the game proceeds anyway.

They probably should've coded it so that on it always pulls the second credit from the opposite side that started the game, unless there aren't any, then it pulls them both from the same side.

Or better yet, maybe no credits get deducted at all when start is pressed, and the credits all come out only after the mode is selected (not deducting it when start is pressed might violate some bios rule though).
 
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city41

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Or better yet, maybe no credits get deducted at all when start is pressed, and the credits all come out only after the mode is selected
It looks to be both. 1 credit is immediately deducted when you press start. The other credit is deducted if you decide to do a two player game.
 

city41

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btw KOF94 in Euro/MVS mode lets you push 1p or 2p start once it has two credits. But if you push 2p start, it consumes both of them and you get a versus game. I would imagine most neo fighters act like that?

I never knew this. It's interesting how something seemingly so simple can be different across regions.
 

Neo Alec

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btw KOF94 in Euro/MVS mode lets you push 1p or 2p start once it has two credits. But if you push 2p start, it consumes both of them and you get a versus game. I would imagine most neo fighters act like that?

I never knew this. It's interesting how something seemingly so simple can be different across regions.
That's really stupid. I can imagine someone doing that because they prefer the 2-player side and getting an unwanted versus game. Luckily most people only add one credit at a time, so this stuff probably went mostly unnoticed.

Anyway, I think I have enough info for the one sentence going in my video at least. I appreciate the help!
 
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