.text
        .global mystrspn
mystrspn:
        push    %ebp
        mov     %esp, %ebp
        push    %esi
        push    %edx
        mov     8(%ebp), %eax
        mov     12(%ebp), %esi
        movl    $0, %ebx
continue:
        movzb   (%eax), %ecx
        movzb   (%esi), %edx
        sub     %edx, %ecx
        jz      equal
        movzb   (%eax), %ecx
        inc     %esi
        movzb   (%esi), %edx
        test    %edx, %edx
        jnz     continue

        jmp     end
equal:
        movzb   (%eax), %ecx
        movzb   (%esi), %edx
        inc     %ebx
        inc     %eax
        movzb   (%eax), %ecx
        cmp     $0, %ecx
        jz      end
        mov     12(%ebp), %esi
        movzb   (%esi), %edx
        jmp     continue

end:
        mov     %ebx, %eax
        pop     %edi
        pop     %edx
        pop     %esi
        movl    %ebp, %esp
        popl    %ebp
        ret