How to compare values ​​in emulators?

[SilverRabbit90]

I have tried to do some cheats on some emulators (PCSX2 and Dolphine), some cheats are easy to do those that only concern the character used. Cheats that have common values ​​such as the Hp of the playable character and that of the enemies crash the emulator or make both enemies and allies immortal.

For example this code crashes the game:

[ENABLE]

aobscan(INJECT,10 0F 38 F1 7C 33 08 8D) // should be unique
alloc(newmem,$1000,INJECT)

label(code)
label(return)

newmem:
//Offset 210 my (float)2 enemy (float)4.600602988E-41

cmp [rbx+210],(float)2
jne code

nop 6

jmp return


code:
movbe [rbx+rsi+08],edi
jmp return

INJECT+01:
jmp newmem
nop
return:
registersymbol(INJECT)

[DISABLE]

INJECT+01:
db 0F 38 F1 7C 33 08

unregistersymbol(INJECT)
dealloc(newmem)


What do I have to do to make this type of code work?

Thx for the help




Here is my Cheat Engine Tutorial:

Spoiler

[Link]

[TheByteSize]

your comparison can come across null or invalid value which crash the game. either find a better spot to check or make sure [rbx+210] contain valid value that can be used to compare at all time. (float)4.600602988E-41 usually an indication for bad spot to check.

[SilverRabbit90]

Ok thanks I'll try to look for an Offset with better values, this thing is making me crazy finding the correct values ​​in the correct offsets in a normal PC game is quite easy and fast, in an emulator it is all the more tedious.
In any case, wasn't the comparison I made wrong? For example, do I have to write something like?

cmp [rsi+210],(float)2

Maybe i have to use rsi instead of rbx...

[SilverRabbit90]

your comparison can come across null or invalid value which crash the game. either find a better spot to check or make sure [rbx+210] contain valid value that can be used to compare at all time. (float)4.600602988E-41 usually an indication for bad spot to check.

I solved with something like this:

[ENABLE]

aobscan(INJECT,10 0F 38 F1 7C 33 08 8D) // should be unique
alloc(newmem,$1000,INJECT)

label(code)
label(return)

newmem:
//Offset 10 my C8000000 enemy A0000000
//Offset 40 my 09000000 enemy 1A000000
//Offset 6C my 0 enemy (int)2348812288
//Offset 23C my 'ib_spideywrestlestealth' enemy ???
//Offset 320 my 0 enemy 32831
//Offset 340 my #14421180 enemy #00000000
//Offset 3A0 my (int)1354156800 enemy 0
//Offset 47D my 128 enemy 0
//Offset 714 my #01000000 enemy 00000000
//Offset 3A0 my (int)1354156800 enemy 0
//Offset EA0 my D1B35DBF enemy 00000000

cmp [rbx+rsi+6C],0
jne code

nop
nop
nop
nop
nop
nop

jmp return

code:
movbe [rbx+rsi+08],edi
jmp return

INJECT+01:
jmp newmem
nop
return:
registersymbol(INJECT)

[DISABLE]

INJECT+01:
db 0F 38 F1 7C 33 08

unregistersymbol(INJECT)
dealloc(newmem)



It was simpler than I thought XD

[GreenHouse]

cmp [rbx+rsi+6C],0
jne code

nop
nop
nop
nop
nop
nop

jmp return

code:
movbe [rbx+rsi+08],edi
jmp return

You don't need all those 'nop' there though. 'Nop' means 'do nothing', so you're telling it to 'do nothing' 6 times instead of just not having anything there, which would pretty much be the same as doing nothing.

[SilverRabbit90]

cmp [rbx+rsi+6C],0
jne code

nop
nop
nop
nop
nop
nop

jmp return

code:
movbe [rbx+rsi+08],edi
jmp return

You don't need all those 'nop' there though. 'Nop' means 'do nothing', so you're telling it to 'do nothing' 6 times instead of just not having anything there, which would pretty much be the same as doing nothing.

Yes, I know thanks, if you want you can also write like this:

cmp [rbx + rsi + 6C], 0
jne code

nop 6

jmp return

I had written to better understand XD

[GreenHouse]

Yes, I know thanks, if you want you can also write like this:

cmp [rbx + rsi + 6C], 0
jne code

nop 6

jmp return

I had written to better understand XD

Well, it's still the same thing I said, you don't need to add 'nop 6' to do nothing. It's just adding unnecessary extra bytes that don't do anything.

[SilverRabbit90]

Yes, I know thanks, if you want you can also write like this:

cmp [rbx + rsi + 6C], 0
jne code

nop 6

jmp return

I had written to better understand XD

Well, it's still the same thing I said, you don't need to add 'nop 6' to do nothing. It's just adding unnecessary extra bytes that don't do anything.

I really did not know this, thanks you taught me something useful **




Here is my Cheat Engine Tutorial:

Spoiler

[Link]