Question

基本上我要做的就是转换这块c ++＆amp; amp;组装成纯粹的汇编，我有点困惑如何将for循环和其余部分转换为汇编，如果有人能让我知道我哪里出错将会很棒。

这是原作

void encrypt_chars (int length, char EKey)      // Encryption Function.

{   char temp_char;                     // Char temporary store.

for (int i = 0; i < length; i++)    // Encrypt characters one at a time.
{
    temp_char = OChars [i];         // Orignal Chars.

    __asm {                         // Switch to inline assembly.

        push   eax                  
        push   ecx                  

        movzx  ecx,temp_char        
        push   ecx                  
        lea    eax,EKey             
        push   eax                  
        call   encrypt4             // Call the encryption subroutine 
        add    esp, 8                
        mov    temp_char,al         

        pop    ecx                  
        pop    eax                  
    }
    EChars [i] = temp_char;         // Store encrypted char in the encrypted chars array.
}
return;

然后，这是我尝试将c ++部分转换为汇编，这是我正在努力的事情，并希望得到一些指示 -

void encrypt_chars(int lengths, char EKey)  // Encryption Function.

{
    char temp_char; 
    __asm { 
    mov         dword ptr[i], 0
    jmp         encrypt_chars
    mov         eax, dword ptr[i]
    add         eax, 1
    mov         dword ptr[i], eax
    mov         eax, dword ptr[i]
    cmp         eax, dword ptr[lengths]
    jge         encrypt_chars 

    mov         eax, dword ptr[i]
    mov         cl, byte ptr[eax]
    mov         byte ptr[temp_char], cl

    push   eax                  
    push   ecx                  

    movzx  ecx,temp_char        
    push   ecx                  
    lea    eax,EKey             
    push   eax                  
    call   encrypt4             // Call the encryption subroutine 
    add    esp, 8                
    mov    temp_char,al         

    pop    ecx                  
    pop    eax                  


    mov         eax, dword ptr[i]
    mov         cl, byte ptr[temp_char]
    mov         byte ptr[eax], cl

}
return;

Answer 1

这是for循环的汇编示例：

mov R1, #5  ; This is the limit of the loop
mov R0, #0  ; R0 is the loop index, initialize the loop index variable.
loop:
  cmp R0, R1 ; Part of the compare expression in for loop.
  bge loop_exit;
;
;  The statement block for the for loop.
  inc R0   ; The increment part of the for loop
  b   loop ; Loop around to the compare part of the loop.

; First statement after the for loop
loop_exit:

将此C ++ for循环转换为汇编语言

1 个答案: