Item Hacking (Skeans and Rename Card)

Hey, everyone! So I'm pretty new to hacking -- just yesterday did my first successful hack to turn every instance of 'GP/Gp' into 'Gil'; I'm still praying I didn't write 'il' over a character I actually need somewhere... -- and I've been sitting down with usME trying to figure out how to make some item adjustments. I'm working on a hack -- eventually it's going to be as complete as I can make it, for now it's just ability system -- for which I want to create some new items, and because I'm anal about organisation, I'm trying to not only overwrite existing items, but actually reorder them so I can group my new items together on the list.

I've got two problems (so far, anyway), although I expect they're connected. I'm trying to a) move (or possibly remove) the Rename Card, but usME doesn't seem to list its rename functionality anywhere so I'm assuming it's hardcoded to the item ID? (like with Tintinnabar/item 229) in which case whatever item ends up with that same ID would bring up the rename menu, yes? and b) move the existing skeans as well as create old ones, but I similarly can't figure out how they're connected to the 'spell' abilities called when they're thrown.

I'm really getting into usME, am comfortable with hex editing (I've done a fair bit of save editing in the past and have a half-complete map of the CC:FFVII save file somewhere), and while I haven't done any ASM hacking before, I'm definitely willing to get my hands dirty with it. So if anyone has an idea of where I could /start/ with this, that'd be awesome! I mean, obviously if anyone knows exactly how to fix it, that'd be great, too, but something to narrow it down a bit would be a big help, too.

The check for the rename card item id is done here:

Code:

C3/8AA5:    C9E7        CMP #$E7
C3/8AA7:    F017        BEQ $8AC0

By changing that E7 to another item number, you can call the rename screen for another item. By using NOP (EA) on those 4 bytes, you remove the pop-up of the rename screen.


As for you skean question, here is the relevant code:

Code:

C2/2708: A2 04        LDX #$04
C2/270A: DF 78 27 C2  CMP $C22778,X (is the tool or skean one that uses a spell?)
C2/270E: D0 06        BNE $2716     (if not, branch)
C2/2710: FF 7D 27 C2  SBC $C2277D,X (if yes, subtract constant to determine its spell number)
C2/2714: 80 37        BRA $274D     (see, certain Tools and Skeans just load spells to do their work)

                    (Bio Blaster will use spell 7D, Bio Blast
                     Flash will use spell 7E, Flash
                     Fire Skean will use spell 51h, Fire Skean
                     Water Edge will use spell 52, Water Edge
                     Bolt Edge will use spell 53, Bolt Edge

And the tables used in the above code (this is where you would need extra room):

Code:

(Data - item numbers of Tools and Skeans that use spells to do a good chunk
of their work)

C2/2778: A4  (Bio Blaster)
C2/2779: A5  (Flash)
C2/277A: AB  (Fire Skean)
C2/277B: AC  (Water Edge)
C2/277C: AD  (Bolt Edge)

(Data - constants we subtract from the above item #s to get the numbers
of the spells they rely on)

C2/277D: 27
C2/277E: 27
C2/277F: 5A
C2/2780: 5A
C2/2781: 5A

Edit: You could move those two tables elsewhere in bank C2 to have more room and add extra entries. Then there would be the above and some other code in bank C2 to modify. You can make a search for "skean" in the C2 disassembly to have a better idea of how it works.

By using NOP (EA) on those 4 bytes, you remove the pop-up of the rename screen.

-- to clarify, that means it would become:

Code:

C3/8AA5:    EAEA
C3/8AA7:    EAEA

correct? To remove the pop-up entirely, I mean.

As for the rest of it, thank you so much! That is exactly what I was looking for; I'll sit down with it and puzzle through what I can. (Free-space-wise in C2, I know there's lists around for where free space is, but I can generally assume that if it's a block of FF, it's not used for anything, right?)

Code:

C3/8AA5:    EAEA
C3/8AA7:    EAEA

This is correct.

Free-space-wise in C2, I know there's lists around for where free space is, but I can generally assume that if it's a block of FF, it's not used for anything, right?

Yes this is right. You can check the list posted by Gi Nattak.