Disassemble a mapper2 game which with 218K pro and no chr

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xian106
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Disassemble a mapper2 game which with 218K pro and no chr

Post by xian106 » Mon Aug 29, 2005 8:04 pm

I want to disassemble a game "RAINBOW ". It's Mapper 2 and have no CHR,just 128K program rom. So I want to get its CHR date too.
Who could give me an advice or tel me what tool I can use.
Thank you.

tepples
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Post by tepples » Mon Aug 29, 2005 9:21 pm

There are two possibilities:
  1. The CHR data is stored uncompressed in PRG ROM. This is the case for Ikari Warriors. Use a tile editor such as Tile Layer, 8TED, or Tile Molester to view the tile data; just don't head straight for the second half as you would with a VROM game. You may also have to switch between normal NES format and a 1-bit-per-pixel format used for some games' text fonts.
  2. The CHR data is stored compressed in PRG ROM, more than likely with a run-length codec. This is the case for Contra, The Legend of Zelda, and Who's Cuter. You'll need to make or find a tool to decompress the graphics.

Celius
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Post by Celius » Mon Aug 29, 2005 9:29 pm

Um, are you saying you want to get it's character data too? Well, I'm not quite sure of what you're asking, are you saying you want to get the character data in a seperate file? Well, if you are, open up the game in a tile editor such as YY-CHR, and scroll down until you get an area with graphics that you know are actual graphics, and not hibber jibber graphics that aren't used in the game. Once you do that, select the graphics and copy/paste them into a new file, and there you go. Again, I'm not quite sure what you were asking for, so I don't know if that was valueble info. But if you're trying to change the graphics in the game once you dissassemble it, it will be alot harder than you think, because the graphics are coded into the PRG file, which explains why there's no CHR ROM.

xian106
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Post by xian106 » Tue Aug 30, 2005 12:34 am

Thank you .
Last edited by xian106 on Tue Aug 30, 2005 12:38 am, edited 1 time in total.

xian106
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Post by xian106 » Tue Aug 30, 2005 12:36 am

I want to change a mapper 2 game to a MMC3 game using VROM.
I don't know how could I do that. But I think,
1 I must find the CHR data which is in PRG rom now,and cut them in VROM for MMC3
2 I must find where he changed the bank,and change them to MMC3 mode.
Is it right?I don't how to do it. Could you help me?Tel me what I must do first ,and second...etc..give me a way to think. Thank you.


And tepples,how can I know it's compressed or not? I using a tile editor to open it,and find somewhere like the CHR data,It is close whith actual graphics.So it is stored uncompressed,yes?

Celius,I use a tool,find somewhere is the CHR data.But I find CHR data is scattered not just in one place.And there are some data I am not sure it's CHR data or PRG rom. So I think "select the graphics and copy/paste them into a new file" is very hard. Could you give me some advice?


Say again,What I want to do is just change this game to MMC3 mode with a VROM. The game name is RainBOW,and it have no CHR data just have 128K PRG rom,and using mapper 2. If you want get this game please give me your E-mail. Thanks for your help! My English is poor,don't laugh at me~ sorry.
Thank you .

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Memblers
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Post by Memblers » Tue Aug 30, 2005 7:42 am

A lot of CHR viewers will let you adjust the viewing offset (I think with the cursor keys, usually). That will help, since CHR tiles have to aligned by 16 to be viewed (and in PRG-ROM, they'll be offset by whatever code/data is around them). If the tiles are uncompressed, they should look perfect once you adjust the alignment.

If the tiles are compressed, an easy way to extract them without decoding them would be to use an emulator like NESten. You'd run the game so the graphics load, look at the pattern tables and save a copy of PPU memory. I've used this trick before with Hot Seat Harry and Munchie Attack to quickly throw together a CHR-ROM version of them (they both used compression on the tiles).

xian106
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Post by xian106 » Tue Aug 30, 2005 5:32 pm

Need I get the character data Or do other first?
I have no a clear thoughtway

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Bregalad
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Post by Bregalad » Wed Aug 31, 2005 8:54 am

Keep in mind that CHRAM and CHROM are usually not compatible, assuming that the original game uses customized tilesets that can't be done with CHROM or special graphic effects that CHROM can't reproduce.
I'm not sure of what you really want to do tough. It's still not impossible in function of how the game does actually work, so more info is needed.
PS: I'm fairly happy to see that I'm not the worst english speaker in there, but I'd reccomand to you to practice a lot, just like I did, hehe.
Life is complex: it has both real and imaginary components.

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Memblers
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Post by Memblers » Wed Aug 31, 2005 9:20 am

Yeah, like Bregalad said you'd better check if the game uses CHR-RAM tricks. To do that, you could play the game in an emulator with a pattern table viewer, and see what kind of changes happen to the tiles. If they only change all at once it'd be ok with ROM, but if the game is changing individual tiles randomly, converting it to CHR-ROM will be kinda difficult.

xian106
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Post by xian106 » Wed Aug 31, 2005 6:37 pm

Yes,tiles only change all at once.

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Bregalad
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Post by Bregalad » Thu Sep 01, 2005 9:45 am

Then check with FCE Ultra XD with it's cool quick breakpoint feature for any write to PPU $0-$1000 then trace the algorithm that does that. If it does just read ROM and write to the PPU then you just have to copy from this ROM aera to your new CHR data. Else, you have to hack the game or something to be able to get all its CHR data, and you may also do check for it in savestates.
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byemu
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Re: Disassemble a mapper2 game which with 218K pro and no ch

Post by byemu » Tue Apr 09, 2013 3:46 am

I can made the chr data~~

I decoder scuedd the jackal and rush data!

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