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I have a problem with STD operand in assembler. When i use it in the next source:

;------------------------------------------------------------------------------------------

IsProgRunning PROC
    LOCAL  ActivProgsCount:DWORD

    mov    dword ptr ActivProgsCount,0
    
    invoke CreateToolhelp32Snapshot, TH32CS_SNAPPROCESS, NULL
    mov    SnapShotHandle,eax  
    mov    lppe.dwSize, sizeof lppe
    invoke Process32First, SnapShotHandle, addr lppe
    invoke Process32Next, SnapShotHandle, addr lppe

lab1384:
    invoke  lstrlen, addr lppe.szExeFile
    mov     esi, offset lppe.szExeFile
    add     esi, eax
    invoke  lstrlen, addr curprogname
    mov     edi, offset curprogname
    add     edi, eax
    mov     ecx, eax
    ;--------------------
;    std                             ;Here is a crash
    ;--------------------
    repe    cmpsb
    jne     lab1427    
    inc     dword ptr ActivProgsCount
    cmp     dword ptr ActivProgsCount, 1
    jbe     lab1427
    invoke  CloseHandle, SnapShotHandle
    mov     eax,dword ptr ActivProgsCount       
    cld
    RET

lab1427:
    invoke  Process32Next, SnapShotHandle, addr lppe
    cmp     eax,0
    jne     lab1384
    invoke  CloseHandle, SnapShotHandle
    mov     eax,dword ptr ActivProgsCount       
    cld

    RET
IsProgRunning ENDP

;------------------------------------------------------------------------------------------

When i delete STD operand and procedure work. This problem i have with Windows XP Professional Version 2002 Service pack 2.
It is strange for me that this problem is not present in other ms windows and ms windows versions.
Can anybody explain what is wrong !!! I want to use STD but i can not in this specific version of Windows XP

martidim, when using STD you must use CLD
  * before returning from a callback
  * before calling any external code