Calculationg time in game msg loop

I'm playing with the original Quake2 game source code for Windows. There is the code which me some doubts an questions.

Sys_Milliseconds function implementation (q_shwin.c):

/*
================
Sys_Milliseconds
================
*/
int curtime;
int Sys_Milliseconds (void)
{
    static int      base;
    static qboolean initialized = false;

    if (!initialized)
    {   // let base retain 16 bits of effectively random data
        base = timeGetTime() & 0xffff0000;
        initialized = true;
    }
    curtime = timeGetTime() - base;

    return curtime;
}

Sys_Milliseconds function usage (sys_win.c) - the main game loop:

...
    oldtime = Sys_Milliseconds ();

        /* main window message loop */
    while (1)
    {
        // if at a full screen console, don't update unless needed
        if (Minimized || (dedicated && dedicated->value) )
        {
            Sleep (1);
        }

        while (PeekMessage (&msg, NULL, 0, 0, PM_NOREMOVE))
        {
            if (!GetMessage (&msg, NULL, 0, 0))
                Com_Quit ();
            sys_msg_time = msg.time;
            TranslateMessage (&msg);
            DispatchMessage (&msg);
        }

        do
        {
            newtime = Sys_Milliseconds ();
            time = newtime - oldtime;
        } while (time < 1);
//          Con_Printf ("time:%5.2f - %5.2f = %5.2f\n", newtime, oldtime, time);

        //  _controlfp( ~( _EM_ZERODIVIDE /*| _EM_INVALID*/ ), _MCW_EM );
        _controlfp( _PC_24, _MCW_PC );
        Qcommon_Frame (time);

        oldtime = newtime;
    }
...

Now I'm wondering is it at all possible for the time variable to be < 1? since the oldtime will ALWAYS be < then newtime just because we take the newtime AFTER the oldtime!?

Can You be so nice and try to explain it to Me. Thx.