大家好，我是汇编语言 x86 的新锐学习者，我正在尝试从一组加密指令中生成 CDECL 调用约定。我相信我在执行公约的过程中会出错。以下是作为问题给出的原始指令集和功能。还包括我的尝试（如果它完全错误，对汇编语言非常陌生，请原谅）。我在 C++ 开发设置中使用 Visual Studio 2013。
几行给出的警告是——警告 C4409：非法指令大小（在指令前使用“@”符号来标记适用的行）
此外，我还收到 2 个警告——警告 C4731:'encrypt_chars':'frame pointer register'ebp' 由内联汇编代码修改（在它适用的行之前使用了 '$' 符号）
void encrypt_chars (int length, char EKey)
{ char temp_char; // char temporary store
for (int i = 0; i < length; i++) // encrypt characters one at a time
{ temp_char = OChars [i];
__asm {
//------------------------ORIGINAL CODE-------------------------------------------//
//--------------------------------------------------------------------------------//
//push eax // save register values on stack to be safe
//push ecx //
//movzx ecx,temp_char //
//lea eax,EKey //
//call encrypt4 // encrypt the character
//mov temp_char,al //
//pop ecx // restore original register values from stack
//pop eax //
//--------------------------------------------------------------------------------//
//---------------------------------CDECL VERSION----------------------------------//
push eax //save register values on stack
push ecx
@push EKey //save orginal values of parameters
@push temp_char
call encrypt4 //call function
add esp, 8 //clean parameters of stack
mov temp_char, al //move the temporay character into a 8bit register
@pop temp_char //recover register values
@pop EKey
pop ecx
pop eax
//--------------------------------------------------------------------------------//
}
EChars [i] = temp_char; // Store encrypted char in the encrypted chars array
}
return;
这是子程序：
encrypt4:
//-------------------------ORGINAL CODE----------------------------------------------//
//push edi
//push ecx
//not byte ptr[eax]
//add byte ptr[eax], 0x04
//movzx edi, byte ptr[eax]
//pop eax
//xor eax, edi
//pop edi
//rol al, 1
//rol al, 1
//add al, 0x04
//ret
//-----------------------------------------------------------------------------------//
//-------------------------CDECL VERSION---------------------------------------------//
push ebp //save old base pointer value
$mov ebp, esp //set new base pointer value
push edi //destination index register used for string, memory array copying, setting and for far pointer addressing with ES (push EDI onto stack)
push ecx //counter register, used as a loop counter (push 'Char' onto stack)
mov eax, [ebp +8] //move value of parameter 1 into eax
mov ecx, [ebp +12] //move valye of parameter 2 into ecx
not byte ptr[eax] //ones complement negation byte pointer used with the 'EKey' single byte location address
add byte ptr[eax], 0x04 //byte pointer used to add 4 in hexidecimal to the 'EKey' single byte location address
movzx edi, byte ptr[eax] //moves the value of 'EKey' address to EDI using zeros instead of a sign bit
pop eax //pop value of 'character to be encrypted' from stack
xor eax, edi //XOR 'character to be encrypted' with EDI value, this give the 'encrypted value of the source character'(stage 1)
pop ecx //recover register value
pop edi //pop orginal address of EDI from stack
rol al, 1 //rotates the 'encrypted value of the source character' register(stage 2) left by 1 bit, leaves a carry for my test string 'manutd$'
rol al, 1 //rotates the 'encrypted value of the source character' register(stage 3) left by 1 bit, leaves a carry for my test string 'manutd$'
add al, 0x04 //adds 4 in hexidecimal to 'encrypted value of the source character'(final stage)
mov esp, ebp //deallocate values
$pop ebp //restore callers base pointer value
ret //return from procedure
//-----------------------------------------------------------------------------------//
任何将不胜感激。谢谢