How to registersymbol?

[Paul44]

^:

alloc(infPoints,8)
...
mov [seePoints],rsi

cmp [infPoints],1
jne code

push r15
mov r15,SetPoints
mov r15d,dword ptr [r15]
mov [rsi+18],r15d
pop r15
...

if the game gives you them mem_issues, you'll have to stick to the same principle everywhere (like in every script in that table):
> basically your cpu tries to mov/cmp a register with a value away past +2GB... and fails (offset too big, etc)
(in worst case scenario, CE will "screw up" the injection altogether ~ i've seen this already plenty of times; iow you'll crash !)
> by moving your label's mem_address to a registry, it "just" compares 2 reg_values on the stack... sort of
(there are some topics @CEF discussing/explaining this ~ mem_mgmt is not my thing)

*******************

alloc(infPoints,4) <= int 4bytes
...
push r15
mov r15,seePoints
mov [r15],rsi

mov r15,infPoints
cmp [r15],1
jne code

mov r15,SetPoints
mov r15d,dword ptr [r15]
mov [rsi+18],r15d

code:
pop r15 <= just make sure r15 is properly pop-ed
movsxd rdx,dword ptr [rsi+18]
test rdx,rdx
mov rcx,rax
jmp return

*******************
=> your original code might work today, but not tomorrow. it all depends on how windows allocate/offer memory to CE, i guess...

ps: video - yep, that guy is really good; any of his videos are worth to watch... (~ Chris Fayte)

[jgoemat]

Couple of things I'd mention, I'd be interested in what other people think...

When I add data and register a symbol, I like to do 'align 10' to make sure it is aligned. I think this has minor performance but alignment of some sort is required by some SSE instructions. Personally I just hate seeing the address end in something like a 7 in my table.

Code: Select all

align 10
SetPoints:
  dd #100

Second, be cautious of the register sizes. It looks like the code in your final works because you use 'r15d' as a 32-bit register, but if you did 'mov r15, dword ptr [SetPoints], the 'dword ptr' is meaningless and it ends up loading 64 bits into r15:

Code: Select all

  mov r15, dword ptr [SetPoints]
  // r15 is now DEAD2222BEEF1111
  ret

align 10
SetPoints:
  dd BEEF1111
  dd DEAD2222

Not realizing that has caused me grief in the past and it can be hard to realize what's happening. If you just do 'mov r15d, dword ptr [SetPoints]' that sets the lower 32 bits, but the upper 32 bits may be anything. If you want to do that, do 'xor r15,r15' first to zero the top 32 bits.