Stage select on the fly

[JonteP]

I just started learning about the cheat system in MAME/MESS and have started to become comfortable in making stage select cheats in various console games.
Now I got the idea that it would be fun to be able to change the stage "on the fly"; that is the stage will chage immediately as you toggle between the values.

I have 2 ideas how to go about this, but have no idea how to implement them.
1. Write the stage # at the appropriate RAM location. Write a jumper opcode to the stage load code after the currently executed opcode.
2. Write the stage # at the appropriate RAM location. Use the cheat system to jump to the stage load code adress.

Now, alt. 1 would require a function that lets you fetch the currently executed adress (and what opcode is executed so you know where to write the jumper)
alt. 2 would require a function in the cheat system to perform that jump.

Is there any function like this? Or is there another solution to work around this issue? Maybe I'm just missing the obvious. As I said, I'm sort of a newbie on this still.

Thanks for any help!

/J

[Pugsy]

All that depends on how the game is programmed, there are no functions in the cheat engine to do something like that. It could only be done by rewriting the games code so you'd have to be fairly handy with the assembler of the chosen game...and it would be an immense amount of work for a single game - it's not something you could easily replicate for other games either.