Error c2400

[Hawlong]

Why this error
error C2400: inline assembler syntax error in 'first operand';
i use [visual studio 2010]
error here [mov [offset],esi]

void __declspec(naked) ourFunct()
{
   int offset;
    __asm
    {
	//inc [esi]
	mov [offset],esi
        push edi
        mov edi, [esp + 0x14]
        jmp jmpBackAddy
    }
}

[kigar64551]

Try renaming your local variable offset into something else, I suppose.

The keyword "offset" is reserved in assembler language:
https://docs.microsoft.com/en-us/cpp/assembler/masm/operator-offset?view=msvc-170

[Hawlong]

Thanks so much , it's work .

void __declspec(naked) ourFunct()
{


    __asm
    {
	//inc [esi]
	mov [buffer_ptr], esi
        push edi
        mov edi, [esp + 0x14]
        jmp jmpBackAddy
    }
	
}

why return 0
i use this cout << "ESI address "<<uppercase << hex << buffer_ptr << endl;

try to use it like this but got errors

void __declspec(naked) ourFunct()
{

    DWORD  buffer_ptr;
    __asm
    {
	//inc [esi]
	mov [buffer_ptr], esi
        push edi
        mov edi, [esp + 0x14]
        jmp jmpBackAddy
    }
	return buffer_ptr;
}

error C2490: 'return' not allowed in function with 'naked' attribute

[kigar64551]

Hawlong wrote:

error C2490: 'return' not allowed in function with 'naked' attribute

To my understanding, function declared with "naked" attribute has no (compiler-generated) prolog or epilog.

In other words, the compiler does nothing to grab the function's arguments from the stack (should they be passed on the stack rather than in registers), or to put the return value onto the stack (or into the register where the result is expected) – which explains why a "normal" return is not possible in such function. Also the compiler does nothing to save/restore "callee-saved" registers. You have to do all that in your ASM code...

[Hawlong]

thanks so much kigar64551 .

[seeplus]

Just for info. If you compile with VS as 64 bit, you can't use in-line assembler code.