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 Post subject: Strikers 1945 (Japan, unprotected)
PostPosted: Wed Apr 10, 2019 2:59 am 


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Clone s1945jn: Slowdown in certain scenarios. pooyan (ID 03693)

Is this issue MAME-exclusive (an emulation bug) or does that game version also suffer from it in the PCB?
If the latter is true, you may want to revise the highscore table for Strikers 1945, since the current best:
https://www.youtube.com/watch?v=YKYUKsZW6UA
is being played on this particular rom; pay attention to the music:
https://vgmrips.net/packs/pack/strikers-1945-ym2610-version-psikyo
As far as I know he didn't report playing with this different rom, even though the current thread states that this release has to be studied for differences. At the very least this should warrant a different ladder.


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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Wed Apr 17, 2019 8:50 pm 


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Weird watching this whilst listening to a different soundtrack.
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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Wed May 01, 2019 4:45 pm 


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Wow. I didn't even know this existed! Thx.


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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Wed May 01, 2019 11:30 pm 



Joined: 08 Mar 2019
Posts: 88
I'd be very surprised if this bug didn't occur randomly on the PCB too as it's relatively simple hardware and this version is almost like a prototype* with it being on the older hardware type and I'm inclined to believe it could have issues that weren't fully ironed out.

* although it seems common enough to suggest it was released in some capacity


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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Thu May 02, 2019 9:24 am 


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Sup, MameHaze. I checked the difference between the regular Japan rom and the unprotected one according to MAME's notes.
https://imgur.com/a/8elnRzv
Plasmo's rom lacks the Microchip PIC16C57, which may explain the slowdown.
Of course, that version also has the cheaper sound chip which leads to the different soundtrack.
But also notice how the Hz are slightly lower in the unprotected rom.

EDIT: Apparently Microchip PIC16C57 is just for copy protection. If the game slows down it's more likely due to an earlier version of the code, or even to the different sound chip.
The YM2610 probably requires (offhand) more sample mixing in software than the YMF278B does. The lower refresh rate is also suspect.


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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Thu May 02, 2019 11:20 am 



Joined: 08 Mar 2019
Posts: 88
The Z80 is in charge of the sound hardware anyway, shouldn't cause the main game to slowdown, it's plenty fast enough.

I really think it's just an earlier code revision without some fixes / optimizations.


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 Post subject: Re: Strikers 1945 (Japan, unprotected)
PostPosted: Thu May 02, 2019 11:27 am 


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Can we get in contact with someone that owns the unprotected PCB to test this? Maybe of the MAME team. Because on MAME the issues are undeniable.


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