Can you tell me what editing this assembly value did?

[SirEnder125]

Hello. I used CTRPF search to find the address of gem apples in TKCD.
I then watched the value with GDB debugger, and then edited the value.
Once I edited the value, GDB told me the address of the function that
made that happen (I think). And it was 0x1e8ca0.

I used CTRPF hex editor to edit the ARM value ("instruction"?) at this
address. I don't know what E1A00000 means, but that's what I changed
the value to. After changing 0x1e8c98 through 0x1e8ca0 to E1A000000,
it no longer changed my amount of gem apples when I bought something.
(Which is very useful, but I want to understand what I did.)

If you can tell me what I did exactly, that'd be great!

[RedShyGuy]

E1A00000 is the instruction mov r0, r0 which moves the data from register 0 to register 0. Basically doing absolutely nothing. You could call it nop as that is the instruction name for something which actually does nothing (would be E320F000 btw).

[SirEnder125]

Okay, thanks. One more thing that I don't understand, though.
Why do I have to edit all 3 values? (Those of the addresses
0x1e8c98 to 0x1e8ca0)

[RedShyGuy]

I don't know how the function looks like so I can't tell you why.

[SirEnder125]

Oh, of course. Sorry. Thanks for the help. 😉

[SirEnder125]

Hello. I was wondering, if I were to find the address of a ASM line that edits a value,
could I make a hook on that line? And maybe print something every time that value
is edited? If so, how would you go about doing this?

[RedShyGuy]

Uuh thats weird. If I recall correctly that address belongs to the function which sets money. So it really shouldn't do anything with weed lol. But I can look at it tomorrow to make sure.

[SirEnder125]

Okay, thank you! It is indeed very weird.

[RedShyGuy]

Soo, I looked at it.
The function you placed your Hook at is the general Encryption function of New Leaf. Used for various things.
And I have no clue why but they encrypt the counter for how many weeds you plucked in total it seems lol.
That's why it also notifies when you pick weed.
To fix it just hook here for example: 0x2C02E0

[SirEnder125]

Okay, thanks! I'll try hooking there. :D

[SirEnder125]

Works great! Thanks!!