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Maniac088
Newbie cheater
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Joined: 30 Aug 2014
Posts: 12
Location: Johannesburg, South Africa
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 Posted: Sat Dec 28, 2019 4:07 pm Post subject: AA write double to address [SOLVED] |
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Hi All,
This is probably a stupid question but I can't find anything through the search.
When I use the following in my script:
mov [rbx+00000820],(int)5000 becomes mov [rbx+00000820],00001388
mov [rbx+00000820],(float)5000 becomes mov [rbx+00000820],459C4000
But (double)5000 becomes 0
mov [rbx+00000820],(double)5000 becomes mov [rbx+00000820],00000000
Am I doing something wrong that (double) won't work this way?
Extra Info:
Using Cheat Engine 7.0, Step 4 of the 64 bit tutorial for Ammo
Last edited by Maniac088 on Sun Dec 29, 2019 2:19 am; edited 1 time in total |
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Dark Byte
Site Admin
 Reputation: 458
Joined: 09 May 2003
Posts: 25281
Location: The netherlands
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| Posted: Sat Dec 28, 2019 9:11 pm Post subject: |
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you can only use (double) on instructions that can take a direct full 64 bit value
those are:
and
| Code: |
mov Rreg,(double)xxx
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and that's it, no other instruction supports a direct 64 bit value
what you can do is:
| Code: |
push rax
mov rax,(double)5000
mov [rbx+00000820],rax
pop rax
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ParkourPenguin
I post too much
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Joined: 06 Jul 2014
Posts: 4289
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| Posted: Sat Dec 28, 2019 9:21 pm Post subject: |
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Doubles are 8 bytes in size. There are very few instructions that take 8-byte immediates- that form of the mov instruction is not one of them. Instead of giving an error, CE just truncates the upper half of the value, leaving you with the lower half (i.e. 0).
Do something else:
| Code: | // make sure rax is not in use
mov rax,(double)5000
mov [rbx+820],rax |
Or:
| Code: | // your code
newmem:
// pick an xmm register not in use
movsd xmm0,[myValue]
movsd [rbx+820],xmm0
// allocated somewhere else
newmem+500:
myValue:
dq (double)5000 |
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I don't know where I'm going, but I'll figure it out when I get there. |
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Maniac088
Newbie cheater
![]() Reputation: 0
Joined: 30 Aug 2014
Posts: 12
Location: Johannesburg, South Africa
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| Posted: Sun Dec 29, 2019 2:18 am Post subject: |
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| Dark Byte wrote: | you can only use (double) on instructions that can take a direct full 64 bit value
those are:
and
| Code: |
mov Rreg,(double)xxx
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and that's it, no other instruction supports a direct 64 bit value
what you can do is:
| Code: |
push rax
mov rax,(double)5000
mov [rbx+00000820],rax
pop rax
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@Dark Byte, Thank you for the help and explanation. It never crossed my mind that is the problem, just thought I'm working in 64 bits it should work.
| ParkourPenguin wrote: | Doubles are 8 bytes in size. There are very few instructions that take 8-byte immediates- that form of the mov instruction is not one of them. Instead of giving an error, CE just truncates the upper half of the value, leaving you with the lower half (i.e. 0).
Do something else:
| Code: | // make sure rax is not in use
mov rax,(double)5000
mov [rbx+820],rax |
Or:
| Code: | // your code
newmem:
// pick an xmm register not in use
movsd xmm0,[myValue]
movsd [rbx+820],xmm0
// allocated somewhere else
newmem+500:
myValue:
dq (double)5000 |
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@ParkourPenguin Thank you for your help as well and expanding on Dark Byte's post. I will need to keep that truncation in mind.
I actually came pretty close to your memory allocation code but got frustrated.
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Dark Byte
Site Admin
Reputation: 458
Joined: 09 May 2003
Posts: 25281
Location: The netherlands
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| Posted: Sun Dec 29, 2019 3:38 am Post subject: |
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Also, I see this often:
| Code: |
// allocated somewhere else
newmem+500:
myValue:
dq (double)5000
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You can also do:
| Code: |
alloc(myValue,8)
myValue:
dq (double)5000
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that way you don't have to make sure your script is less than 1280 bytes and CE will put it in the same block anyhow
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