MMX-сложение чисел со знаком

.686
.model flat,stdcall
.MMX
option casemap: none
include \masm32\include\kernel32.inc
include \masm32\include\windows.inc
include \masm32\include\user32.inc
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\user32.lib
ExitProcess proto: dword
.data
mas1 db 12,-5,33,11,7,9,-11,10,-31,17,54,32,7,-3,-44,6,81,1
mas2 db 12,-5,33,11,7,9,-11,10,-31,17,54,32,7,-3,-44,6,81,1
masout db 18 dup (0)
buf db 18 dup(0)
ifmt db "%d",0
stdout dword ?
cWritten dword ?
crlf db 0dh, 0ah
.code
_st:
    _paddsb proc
    invoke GetStdHandle,STD_OUTPUT_HANDLE
    mov stdout,eax
    mov eax,18
    mov ebx,8
    xor edx,edx
    div ebx
    mov ecx,eax
    lea esi,mas1
    lea edi,masout
    lea ebx,mas2
m1:
    movq MM0,qword ptr [esi]
    paddsb MM0, qword ptr [ebx]
    movq qword ptr[edi] ,MM0
    add esi,8
    add edi,8
    add ebx,8
    loop m1
    cmp edx,0
    jz exit
    mov ecx,edx
m2:
    mov al,byte ptr[esi]
    add al,byte ptr[ebx]
    mov byte ptr [edi],al
    inc esi
    inc edi
    dec ecx
    jnz m2
exit:
    lea esi,masout
    mov ecx,18
show:
    push ecx
    mov bl,byte ptr[esi]
    movsx eax,bl
    invoke wsprintf,addr buf,addr ifmt,eax
    invoke WriteConsoleA,stdout,addr buf,2,addr cWritten,0
    invoke WriteConsoleA,stdout,addr crlf,2,addr cWritten,0
    pop ecx
    inc esi
    loop show
    invoke Sleep,20000
    invoke ExitProcess, 0
    _paddsb endp
end _st

m2:
        mov al,byte ptr[esi]
        add al,byte ptr[ebx]
        mov byte ptr [edi],al
        inc esi
        inc edi
        [B]inc ebx[/B]     ;добавил
        dec ecx
        jnz m2
exit:
        lea esi,masout
        mov ecx,18
show:
        push ecx
        mov bl,byte ptr[esi]
        movsx eax,bl
        invoke wsprintf,addr buf,addr ifmt,eax
        invoke WriteConsoleA,stdout,addr buf,4,addr cWritten,0
        [B]invoke RtlZeroMemory,addr buf,3[/B]    ;добавил
        invoke WriteConsoleA,stdout,addr crlf,2,addr cWritten,0