Question

我正在开发一个用随机值填充数组的程序，然后将它们按降序排序，然后计算中位数。我有程序工作正常，除了它收到超过100的值，然后程序吐出垃圾。我很确定错误是在我的排序过程或我的显示列表过程中。这是我认为问题所在的代码。关于pastebin的完整代码：http://pastebin.com/5MdWijRa

;sort list
Sort            PROC
    push    ebp
    mov     ebp, esp
    mov     edi, [ebp + 12]
    mov     ecx, [ebp + 8]
    dec     ecx             ;outer loop is set to one less than request
    mov     ebx, 0          ;k=0

L1:
    mov     eax, ebx    ; i = k

    mov     edx, eax    
    inc     edx         ; j = k+1
    push    ecx             ;store the value of the outer loop
    mov     ecx, [ebp + 8]  ; inner loop is set to request

L2:
    cmp     ecx,0
    je      exchangeNext
    mov     esi, [edi + edx*4]  ; store element j of the array 
    cmp     esi, [edi + eax*4]  ;compare to element i 
    jg      greater             
    inc     edx
    loop    L2


greater:
    cmp     ecx,0
    je      exchangeNext
    mov     eax, edx        ; i = j
    inc     edx             ;increase j for the next iteration of the for loop
    loop    L2

exchangeNext:
    lea     esi, [edi+ebx*4]                ;saved to work like a temp variable
    push    esi             ;saved to work like a temp variable
    lea     esi, [edi+eax*4]    ; swapping array[k] and array [i]
    push    esi
    call    exchange
    pop     ecx             ;restore outer loop value
    inc     ebx             ;move forward through the outer loop
    loop    L1

    pop     ebp
    RET     8
Sort        ENDP

exchange    PROC
    pushad
    mov     edx, [edi+eax*4]    ; store the value of array[i]
    mov     esi, [edi+ebx*4]    ; store the value of array[k]
    mov     [edi+eax*4], esi    ; switch the values
    mov     [edi+ebx*4], edx
    popad

    RET     8
exchange    ENDP

;display list 
DisplayList     PROC

;Set up the stack
    push    ebp
    mov     ebp,esp
    mov     edx, [ebp + 16]     ;address of the title string
    mov     esi, [ebp + 12]     ;address of the array
    mov     ecx, [ebp + 8]      ; set request as the loop control
    mov     ebx, 0              ;keep count of how many numbers are printed

;Display the title
    call    WriteString         
    call    CrLf

;Display the numbers
Show:
    mov     eax, [esi]
    call    WriteDec
    mov     edx, OFFSET space
    call    WriteString
    add     esi, 4              ;Move to the next element in the array
    inc     ebx                 ;Counter 
    cmp     ebx, 10
    je      printLine       
    loop    Show
    cmp     ecx, 0
    jmp     endShow

printLine:
    call    CrLf            ;Print to the next line
    mov     ebx, 0          ;reset ebx
    loop    show    

endShow:
    call    CrLf
    pop     ebp
    RET     12
DisplayList     ENDP

Answer 1

这条线造成了混乱：

mov     ecx, [ebp + 8]  ; inner loop is set to request

当内循环的开始增加（inc ebx和后代）时，重复的数量保持在[ebp+8]，这会将循环的末尾移出数组的边界（{ {1}}）。计数器的起始值（[ebp + 12]）也应该减少。

在上一行之前插入该行：

ECX

有些人可能认为这是一个快速而肮脏的解决方案。我＆＃34;滥用＆＃34;函数作为局部变量的参数。

MASM Sorting Array用大于100的数组吐出垃圾

1 个答案: