how to crack a rom?

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By wolf_

Ambassador_ (9774)

wolf_'s picture

30-07-2010, 01:11

I'll upload Oxygene IV to my youtube page this night. But as for MSX, no short term plans.. or actually, tons o' plans, just no results so far.. ^^

But, as flyguille noted, you want a disassembler. And you certainly don't want to crack ROMs yourself, just grab 'm from the net.

By NYYRIKKI

Enlighted (5396)

NYYRIKKI's picture

30-07-2010, 07:09

Yup... like I said... Super-X is the tool for you... It has disassembler & monitor built in... Identifying graphic blocks is also easy with it as well as copying ROMs to disk. If you want to write custom loaders for BASIC or something like that it is also easy to do with Super-X.

By Hrothgar

Champion (479)

Hrothgar's picture

30-07-2010, 09:09

Even when having 'disassembled' roms I assume the resulting code still requires intimite knowledge of MSX assembly language in order to be able to read it. I personally have difficulties 'reading' other people's visual basic scripts or elaborate Excel or Access databases as everyone uses his own style, so I assume reading other persons' ASM codings requires a lot of patience and practice.

By NYYRIKKI

Enlighted (5396)

NYYRIKKI's picture

30-07-2010, 10:50

In ASM coding there is less reasonable ways to code with own style. The problem is the size of code... When we talk about programs that are only few kilobytes then understanding the code is possible without going mad, but when the size grows understanding gets harder in exponent. Usually it is the number of sub routines that really slows down the process of learning. Adding good documentation while reverse engineering sure helps, but that is something that at least I don't do... Eek!

Sometimes the ROMs or parts of them are made with other language than ASM in the first place... in that case you need to learn to see trough the compiled code and imagine the code before compile in order to get big picture of what the coder was thinking... That is really not easy...

By Yukio

Paragon (1541)

Yukio's picture

30-07-2010, 15:31

In ASM coding there is less reasonable ways to code with own style. The problem is the size of code... When we talk about programs that are only few kilobytes then understanding the code is possible without going mad, but when the size grows understanding gets harder in exponent. Usually it is the number of sub routines that really slows down the process of learning.

This could be the case of the Intel 8080, but the Z80 has doubled the registers and there are more Op Codes.
The amount of pushing and popping plus the swapping about registers could be confusing.
There are even instruction that could use 8-bit or 16-bit registers either ...

There are the Main Register Set and the Alternate Register Set.
The Main Register is:
A,F,B,C,D,E,H,L (8-bit registers) ... and could be combined into AF,BC,DE,HL (16-bit registers).
The Alternate Register Set is:
A',F',B',C',D',E',H',L', (8-bit registers) ... and could be combined into AF',BC',DE',HL' (16-bit registers).

Using EX AF,AF' (for pairs AF and AF') and EXX (for pairs BC<->BC',DE<->DE',HL<->HL') swap the values on the 16-bit registers.

By ZanacX

Expert (81)

ZanacX's picture

30-07-2010, 16:45

this is to hardoO i didnt think it would be to hard to read programing code.but there must be a way to see the programing code (to be honest my uncle cracked Knightmare when he was young and increased the lifes up to 99 when you start the game but he died before teaching me MSX BASIC ) so im trying hard to continue with the MSX historySmile,anyway thanx for your answers i think super-x is the right one(thanks NYYRIKKI) ,but if you know how to do it in a real MSX with a real ROM then please enlight meWinkBig smile

By muffie

Paladin (933)

muffie's picture

30-07-2010, 17:31

ZanacX, believe me, this is what you'll need first:

http://en.wikiversity.org/wiki/Introduction_to_Programming

By Yukio

Paragon (1541)

Yukio's picture

30-07-2010, 17:59

After copying the game content it is possible to just use one or two pokes to change the numbers of lives on some games. Now, to find the correct memory address on Real MSX microcomputers ... There are a lot of special software on PC that would allow the people to use trainer versions of the programs (changing the values on memory and with a debuger).

Konami has their own Game Master cartridges to change the number of lives on their cartridges.

A note, it is illegal to to this type of task if you are not a game developer or the owner of a Software House. It is considered a crime in most countries ... If it is illegal on your nation, Just take a trip to another place!

By muffie

Paladin (933)

muffie's picture

30-07-2010, 18:09

That's a very CLEVER advice. If it's illegal in your country, pack everything, take a plane, rent a place (maybe a hotel), start learning how to disassemble a binary,...

Go for it Zanac!

By ZanacX

Expert (81)

ZanacX's picture

30-07-2010, 19:02

i am packing right now the caps are behind my car i'll catch up with you when i get to the hotel Tongue ,just kidding dont worry MSX is dead in my country and i am toooo lucky if i found any one who knows the words MSX, im the only one (not proud to say Eek!) that has MSX stuff (that belongs to my uncle)

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