Tiger Heli on Steam - RAM CHECK C1EA Error

[thaIllsburyFlowboy]

Hi all,

I was wondering if this issue is known with either Steam or the version of the rom that they used (I assume it is emulated). My score was somewhere north of a million and I was a few loops in when the game crashed with this error. If the link below doesn't work, it's the same as in this thread's title. Does Tiger Heli max out beyond a certain score/area like Donkey Kong? Can anyone who understands computers disentangle what a C1EA is? I have gotten to around 1.6 mil in MAME's default version (tigerh.zip) but I feel like the heli is a bit faster in Steam's version. That could just be me hallucinating though. Other than that, it was well worth a few bucks. I like that the shot count is displayed although I wish they'd let you know when you're on a multiple of 8 so I could unlock the second secret car without breaking concentration.

[pegboy]

Can't help with most of that but I do know that in old versions of mame they had the dips set wrong and the ship speed set to slow. It should be set to fast on default settings. That may be why you notice a difference in speed. Im not sure if this was ever fixed in mame or not.

[thaIllsburyFlowboy]

Can't help with most of that but I do know that in old versions of mame they had the dips set wrong and the ship speed set to slow. It should be set to fast on default settings. That may be why you notice a difference in speed. Im not sure if this was ever fixed in mame or not.

Agreed, I have run into it where dip switches are set backwards before. I still feel like this is faster in both modes but it might just be the visual differences (scanlines etc.) playing tricks on me.

This is weird because the error seems to be not an emulation issue but embedded within the game itself. In other words it's presented in 8-bit looking font while Steam, etc. still runs fine, as though this would have actually happened on an eighties arcade machine. So, I wonder if they based it on one of those bootleg roms in the MAME set. Oh well, I'll go back to Wolfmame for high score runs, but boy is that shot counter handy.

[Sumez]

Oh yeah, definitely an internal check that failed, which is really weird to see on a commercially released emulator.
Without knowing anything about this feature in Tiger Heli specifically, it sounds like a checked put in to identify hardware errors - so on an emulator, that should never fail unless there's an error in the emulation!

"C1EA" could be anything, it's just a number presented in hexadecimal. But one assumption I could make is that it refers to an address, either on the RAM IC itself or (probably more likely) from the CPU's perspective. Maybe the game writes a specific value to address 0xC1EA, and then reads the same address and checks if it gets the same value out. If it doesn't, there's an error in the RAM chip.

Usually those checks are performed while booting the game however (I'm sure you've seen lots of ROM and RAM check screens like that), so it's odd to me that you'd get it during gameplay!


I think it's not unlikely that there's simply a bug in the coding of the game, and the emulator/port isn't at fault. But searching for a glitch like that without a savestate to replicate it would be a ton of work. So the best way to confirm that is if someone else here could confirm ever experiencing the same thing on a real PCB or in MAME.


EDIT: According to the MAME driver source code, 0xC1EA is definitely a RAM address. The PCB has 2kb of RAM on CPU space 0xC000-0xC7FF

[thaIllsburyFlowboy]

Oh yeah, definitely an internal check that failed, which is really weird to see on a commercially released emulator.
Without knowing anything about this feature in Tiger Heli specifically, it sounds like a checked put in to identify hardware errors - so on an emulator, that should never fail unless there's an error in the emulation!

"C1EA" could be anything, it's just a number presented in hexadecimal. But one assumption I could make is that it refers to an address, either on the RAM IC itself or (probably more likely) from the CPU's perspective. Maybe the game writes a specific value to address 0xC1EA, and then reads the same address and checks if it gets the same value out. If it doesn't, there's an error in the RAM chip.

Usually those checks are performed while booting the game however (I'm sure you've seen lots of ROM and RAM check screens like that), so it's odd to me that you'd get it during gameplay!


I think it's not unlikely that there's simply a bug in the coding of the game, and the emulator/port isn't at fault. But searching for a glitch like that without a savestate to replicate it would be a ton of work. So the best way to confirm that is if someone else here could confirm ever experiencing the same thing on a real PCB or in MAME.


EDIT: According to the MAME driver source code, 0xC1EA is definitely a RAM address. The PCB has 2kb of RAM on CPU space 0xC000-0xC7FF

Great insights, thanks. I grabbed a savestate of it today, but only after it occurred. There didn't seem to be a predictable pattern again. 902k points, ~5 extra lives and towards the end of stage 4. I did lose count of the loops and time played. I feel like it must be specific to this rom since people have rolled the game over on other ports according to the high score section.

[Sumez]

So it happens frequently on the port then?

Yeah I feel like if it wasn't an error in their emulation, people would have been much more familiar with the error on PCB/MAME. I'm actually super curious what causes it. It's easy to just put Bitwave at fault, but if it requires getting such a massive score, and doesn't (seem to) affect anything else, I can understand why they'd overlook it.

[thaIllsburyFlowboy]

So it happens frequently on the port then?

Yeah I feel like if it wasn't an error in their emulation, people would have been much more familiar with the error on PCB/MAME. I'm actually super curious what causes it. It's easy to just put Bitwave at fault, but if it requires getting such a massive score, and doesn't (seem to) affect anything else, I can understand why they'd overlook it.

Pretty consistent yeah. It happened today around ~870k points. I am hoping it is an easy fix. I shot them an email through the account they have listed with Steam but haven't heard anything.

Let's see if Imgur can help us with sharing a screenshot:



Update - the embed code is still not working; try this link: https://imgur.com/a/ZsbuBEN

[davyK]

There's no region select in that port of Tiger Heli. I have it myself. The default options seems to be for the US version (according to the high score thread for the game). So not sure if that has anything to do with it.

It does feel fast after playing the M2 port but I haven't put enough time in on either to really judge. I certainly haven't got past the 1 loop. The movement feels glacial on the M2 port but maybe that's because I'm playing it on a larger screen on a console.