7
votes
Accepted
What compiler uses a calling convention that uses EAX as the first argument, then pushes onto the stack?
This is probably a program compiled with "Whole Program Optimization" or "Link-time code generation". From MSDN:
When /LTCG is used to link modules compiled with /Og, /O1, /O2, or
/Ox, the ...
- 36.9k
7
votes
Accepted
Register Calling Convention: written in stone, or in mud?
If the compiler can prove that it has all call sites for a given function under its control then it can discard conventions and arrange things around to its liking. Microsoft's C/C++ compiler has been ...
- 2,020
6
votes
Accepted
Returning value from faux DLL
Your faux function is not fixing up the stack on the epilog of the function. It should have
pop ds
pop bp
dec bp
at the end by the calling convention.
If you look at the original function it fixes ...
- 1,341
5
votes
Accepted
How to find the stack and other info in a memory dump? ARM
The only idea I have is to compare the dumps. The places that are same in all dumps are code or read only data. The places that are changing from dump to dump are either stack or section like .bss. ...
- 8,538
4
votes
8086 Function Calling Conventions
Calling conventions are compiler specific, meaning they are specified by the compiler manufacturer like Microsoft, and not by the 8086 manufacturer like Intel. In case you program in Assembler or ...
- 1,974
3
votes
Accepted
What does __return_ptr do in IDA?
The "problem" with your example is that the structure is too small (four bytes), so it fits in a register and is not actually passed on the stack. From the Itanium C++ ABI (used by most GCC ...
- 36.9k
2
votes
Accepted
How can an IA-32 program seemingly compiled with MSVC send its sole argument via EAX?
We can see from this list that IA-32's Delphi/Free Pascal calling convention is the register calling convention. My guess is you're dealing with a binary that's the result of something like this: How ...
- 2,254
2
votes
Accepted
How can I call a function that acts like __thiscall, except the caller cleans the stack?
Sounds like you have a variadic __thiscall function (printf-like). Those use ecx for this but the remaining arguments are pushed onto the stack and the caller cleans it up.
- 36.9k
2
votes
IDA Hex-Rays: How to SAFELY fix incorrect function declarations?
The decompiler decided that ecx is used by sub_431C00 because of push ecx at the beginning of the function which fills the stack slot later used by the variable phkResult, so it may look as if the ...
- 36.9k
2
votes
Accepted
IDA Hex-Rays: How to SAFELY fix incorrect function declarations?
Welcome to RE.SE!
How to understand what the problem is?
When the function is decompiled, IDA checks for its dependencies via dataflow analysis. Basically, it asks which values have to be defined ...
- 2,906
2
votes
Accepted
CreateTimerQueueTimer arguments differs from WinAPI
Yep, I think I've seen a similar case before. It happens very rarely, but because you can do some stunts at the C preprocessor level as well as at the linker level, this happens to work.
In this case ...
- 10.9k
2
votes
Accepted
indirect return value address
From https://github.com/Siguza/ios-resources/blob/master/bits/arm64.md
x8 pointer to where to write the return value if >128 bits, otherwise scratch register
So it seems x8 is used to pass an ...
- 1,391
2
votes
Accepted
What is a "far call" in an x86 or x86_64 cpu
to perform inter segement branching (jump/call) cs needs to be changed
from windbg you can observe kernel code is running in code segment 0x10 while user mode code is running in 0x33 (64 bits) or 0x23 ...
- 16.7k
1
vote
Detours not cleaning the stack correctly
I have found the solution to this problem, which is quite simple. I got confused with the hooked function signature and the __fastcall trick to get a non member function to work with the __thiscall ...
- 197
1
vote
How to call and what means: _DWORD *__thiscall
Basically I've checked with Ghidra to compare and I've found that the signature is different:
void __thiscall FUN_00142860(int param_1_00,undefined4 *param_1,int param_2)
So, basically I just ...
- 161
1
vote
Calling function with string as parameter
At the end I just had to compile as Release.
Thanks to this information:
https://stackoverflow.com/questions/10315041/meaning-of-acronym-sso-in-the-context-of-stdstring/
So it's just a compiler ...
- 161
1
vote
Calling MessageBoxW x64 confused about pointer
First make sure you are using correct calling convention, in 64-bit Windows most APIs expect parameters via registers not push.
An example of calling convention for 64-bit Windows:
lea r9d, uType ...
- 1,267
1
vote
Accepted
Why doesn't alloca_probe follow x64 calling convention?
This is not a standard function but a compiler helper, used by the compiler to perform some necessary housekeeping (allocate extra stack space) so it doesn’t have to follow the ABI for “normal” ...
- 36.9k
1
vote
Lack of arguments before a CALL instruction
Seems like it has 4 arguments, and they are passed through stack, yet the more lines of disassembly above E42D6A needed to make sure. Are those mov and lea instruction confusing you? If you've ...
- 1,860
1
vote
Accepted
How to specify stack-based return values in IDA Pro (GoLang)
I have been in touch with IDA support and unfortunately, right now, there does not seem to be a good way to do this. IDA assumes in many cases that the return value of a function must be stored in a ...
- 61
Only top scored, non community-wiki answers of a minimum length are eligible