Yu-Gi-Oh! Forbidden Memories - Finding what modifies card drops [HELP]

[GFC_]

Hey everyone!

My name is GFC. I'm a speedrunner (attempt to complete games as fast as possible) of the PSX game Yu-Gi-Oh! Forbidden Memories.

For years now we have been doing our best to try to find out how card drops work in this game. Basically, at the end of every duel, you win a card.

We were able to find out what cards drop where, and their percent chance of it, and we made some other small discoveries, but to this day how exactly the cards are selected are beyond us.

We teamed up with people on Neoseeker trying to finally crack the game apart in this sense to no avail. Some of us (like me) have little to no knowledge of game hacking. Others in the community know quite a bit about it and have researched many things far too technical for me to understand without being able to find everything.

In an old thread on this topic here (back in July), it was basically said to just locate the card you won's address, and then trace it back and eventually we should end up at some type of table that describes what factors into how it got there. We had our most knowledgeable members of the community try this, but they were not successful. They said either the trace ends, or it gets so mixed up with variables that it's nearly impossible to follow along.

I myself do not understand much of this, but I do know that we need help in this regard. There are well over 200 people very interested in figuring this out, but it's surprising how much trouble even the smartest among us are having.

I am posting here asking for help on the entire communities behalf on this subject. It may seem extremely simple to other, more experienced users here than it is to us. I also understand it is probably not in the interest of any of you to help in this regard, but even some simple guidance that I can pass off to those who know better than me in the community would be greatly appreciated.

Thanks everyone!

EDIT: I realize I posted this in the wrong section. This should be in the Retro Hacking area. My apologies.

[Helder]

What info do you have in regards to the technical info or whatever you used to determine the cards won. With that info someone here (maybe myself if I find the time) can have an easier time doing this since we will have some details instead of starting from scratch.

The trace basically is used with the Emulator MESS which has a trace log feature which will log every instruction executed which helps immensely in figuring things out and more than likely there is some form of math used to determine a random card based on some other data which can all be discovered (I doubt with ease) on how the game determines what card to give out...... Holy Run On sentence Batman!!

[Duncan Idaho]

What info do you have in regards to the technical info or whatever you used to determine the cards won. With that info someone here (maybe myself if I find the time) can have an easier time doing this since we will have some details instead of starting from scratch.

The trace basically is used with the Emulator MESS which has a trace log feature which will log every instruction executed which helps immensely in figuring things out and more than likely there is some form of math used to determine a random card based on some other data which can all be discovered (I doubt with ease) on how the game determines what card to give out...... Holy Run On sentence Batman!!

Time for me to bump this.

We acquired some of this info via savestating, quite a lot, we are convinced there is some sort of RNG in it, however I did manage to make a big discovery, at the start of every duel there is an unkown number of pre selected cards you may win, the last action determines what you win, this was determined via savestating, before I finishe the duel, I savestated.

Any action before the last hit changes the card, attacking? Changes it, Fusion summoning a monster? Changes it, placing the same monster with a different sign? Changes it again, use the 3D battle feature? Changes the card again.

However a savestate from the very beggining of the duel demonstrates that the cards are pre selected.

[crabchurch]

Bumping this thread. I've been looking into hacking this game for the past week and haven't really gotten any farther than the two above me. Apparently the game was coded on a Macintosh computer which may or may not make it difficult to manipulate with a PC. The .ISO contains two .dat files and these appear to contain the games' code, but this is more of a guess than anything. And using a disassembler hasn't really gotten me anywhere either.