Graphics corruption on The Cure

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By blur2040

Rookie (18)

blur2040's picture

17-02-2017, 16:30

Apologies for the necro-bump, but I can't resist thanking someone for a good thread and making it easier to find for others, too.

I have a Yamaha CX5M and I was experiencing graphics glitches/corruptions when trying to play "The Cure." I found this thread, but the video in the initial post is no longer available, so I wasn't sure if it was the same corruption/glitching as I was experiencing. The results of the corruption though were that the XL2S splash screen was scrambled and when the game began, the graphics were mostly there, but the whole screen would...shift left and right when I attempted to use the whip.

I tried downloading the apparently alternative dump of The Cure posted in this thread, but the download link is dead. I tried finding alternate versions of the ROM elsewhere online, but all have the same issue--this includes the downloads from the XL2S website and the MSXdev contest page.

After exhausting all other options, I attempted to implement the fix that gdx suggested below. I'm not a programmer of any sort and had no clue what I was doing, but I knew enough that I could fudge with the ROM file in a hex editor. After spending a good chunk of time trying to figure out how to identify which location I was at, I was able to implement the changes that gdx suggested. I would note that in the ROM copy I edited, the first two edits (000010 and
00001B) were already implemented.

So, thanks, gdx, your fix works and now I get to play "The Cure."

gdx wrote:

Hap, your version still bugged.

The bug that sets the VDP to 4K RAM mode is not complety fixed. To fix it change following bytes.

000010: 62 -> E2
00001B: 22 -> A2
004065: 22 -> A2

I have found another issue. An OTIR causes a too fast access to the VRAM. To fix it change following bytes.

003835: 3E 00 F3 D3 99 3E 58 -> AF F3 D3 99 3E 58 FB
00383E: FB 21 C0 CA 01 98 00 ED B3 3E 02 ED A3 04 00 -> 21 C0 CA 01 98 00 ED A3 20 FC 3E 02 ED A3 04
00384E: FA -> FB
003851: F7 -> F8

I noticed another bug again: the bats are white on MSX1 instead of gray. I have not found the cause.

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