diff --git a/moo/lib/moo-utl.h b/moo/lib/moo-utl.h
index 264bd26..3330af4 100644
--- a/moo/lib/moo-utl.h
+++ b/moo/lib/moo-utl.h
@@ -602,7 +602,6 @@ MOO_EXPORT moo_uint128_t moo_hton128 (
 );
 #endif
 
-
 #if defined(__cplusplus)
 }
 #endif
diff --git a/moo/lib/std.c b/moo/lib/std.c
index ded7799..d97d8b0 100644
--- a/moo/lib/std.c
+++ b/moo/lib/std.c
@@ -359,6 +359,7 @@ struct xtn_t
 #define GET_XTN(moo) ((xtn_t*)moo_getxtn(moo))
 
 static moo_t* g_moo = MOO_NULL;
+static int g_moo_tick_active = 0;
 
 /* ========================================================================= */
 
@@ -2619,19 +2620,20 @@ static MOO_INLINE void swproc_all (void)
 	/* TODO: make this atomic */
 }
 
+
 #if defined(__DOS__) && (defined(_INTELC32_) || defined(__WATCOMC__))
 
 #if defined(_INTELC32_)
-static void (*prev_timer_intr_handler) (void);
+static void (*dos_prev_timer_intr_handler) (void);
 #else
-static void (__interrupt *prev_timer_intr_handler) (void);
+static void (__interrupt *dos_prev_timer_intr_handler) (void);
 #endif
 
 #if defined(_INTELC32_)
 #pragma interrupt(timer_intr_handler)
-static void timer_intr_handler (void)
+static void dos_timer_intr_handler (void)
 #else
-static void __interrupt timer_intr_handler (void)
+static void __interrupt dos_timer_intr_handler (void)
 #endif
 {
 	/*
@@ -2642,111 +2644,142 @@ static void __interrupt timer_intr_handler (void)
 	*/
 
 	/* The timer interrupt (normally) occurs 18.2 times per second. */
-	if (g_moo) moo_switchprocess (g_moo);
-	_chain_intr (prev_timer_intr_handler);
+	swproc_moo ();
+	_chain_intr (dos_prev_timer_intr_handler);
+}
+
+static void setup_tick (void)
+{
+	dos_prev_timer_intr_handler = _dos_getvect(0x1C);
+	_dos_setvect (0x1C, dos_timer_intr_handler);
+}
+
+static void cancel_tick (void)
+{
+	_dos_setvect (0x1C, dos_prev_timer_intr_handler);
 }
 
 #elif defined(_WIN32)
-static HANDLE g_tick_timer = MOO_NULL; /*INVALID_HANDLE_VALUE;*/
+
+static HANDLE win_tick_timer = MOO_NULL; /*INVALID_HANDLE_VALUE;*/
 
 static VOID CALLBACK arrange_process_switching (LPVOID arg, DWORD timeLow, DWORD timeHigh) 
 {
-	swproc_all ();
+	swproc_moo ();
+}
+
+static void setup_tick (void)
+{
+	LARGE_INTEGER li;
+	win_tick_timer = CreateWaitableTimer(MOO_NULL, TRUE, MOO_NULL);
+	if (win_tick_timer)
+	{
+		li.QuadPart = -MOO_SECNSEC_TO_NSEC(0, 20000); /* 20000 microseconds. 0.02 seconds */
+		SetWaitableTimer (win_tick_timer, &li, 0, arrange_process_switching, MOO_NULL, FALSE);
+	}
+}
+
+static void cancel_tick (void)
+{
+	if (win_tick_timer)
+	{
+		CancelWaitableTimer (win_tick_timer);
+		CloseHandle (win_tick_timer);
+		win_tick_timer = MOO_NULL;
+	}
 }
 
 #elif defined(__OS2__)
-static TID g_tick_tid;
-static HEV g_tick_sem; 
-static HTIMER g_tick_timer;
-static int g_tick_done = 0;
+static TID os2_tick_tid;
+static HEV os2_tick_sem; 
+static HTIMER os2_tick_timer;
+static int os2_tick_done = 0;
 
 static void EXPENTRY os2_wait_for_timer_event (ULONG x)
 {
 	APIRET rc;
 	ULONG count;
 
-	rc = DosCreateEventSem (NULL, &g_tick_sem, DC_SEM_SHARED, FALSE);
+	rc = DosCreateEventSem (NULL, &os2_tick_sem, DC_SEM_SHARED, FALSE);
 	if (rc != NO_ERROR)
 	{
 		/* xxxx */
 	}
 
-	rc = DosStartTimer (1L, (HSEM)g_tick_sem, &g_tick_timer);
+	rc = DosStartTimer (1L, (HSEM)os2_tick_sem, &os2_tick_timer);
 	if (rc != NO_ERROR)
 	{
 	}
 
-	while (!g_tick_done)
+	while (!os2_tick_done)
 	{
-		rc = DosWaitEventSem((HSEM)g_tick_sem, 5000L);
-		DosResetEventSem((HSEM)g_tick_sem, &count);
-		swproc_all ();
+		rc = DosWaitEventSem((HSEM)os2_tick_sem, 5000L);
+		DosResetEventSem((HSEM)os2_tick_sem, &count);
+		swproc_moo ();
 	}
 
-	DosStopTimer (g_tick_timer);
-	DosCloseEventSem ((HSEM)g_tick_sem);
+	DosStopTimer (os2_tick_timer);
+	DosCloseEventSem ((HSEM)os2_tick_sem);
 
-	g_tick_timer = NULL;
-	g_tick_sem = NULL;
+	os2_tick_timer = NULL;
+	os2_tick_sem = NULL;
 	DosExit (EXIT_THREAD, 0);
 }
 
+static void setup_tick (void)
+{
+	/* TODO: Error check */
+	DosCreateThread (&os2_tick_tid, os2_wait_for_timer_event, 0, 0, 4096);
+}
+
+static void cancel_tick (void)
+{
+	if (os2_tick_sem) DosPostEventSem (os2_tick_sem);
+	os2_tick_done = 1;
+}
 
 #elif defined(macintosh)
 
-static TMTask g_tmtask;
-static ProcessSerialNumber g_psn;
+static TMTask mac_tmtask;
+static ProcessSerialNumber mac_psn;
 
 #define TMTASK_DELAY 50 /* milliseconds if positive, microseconds(after negation) if negative */
 
 static pascal void timer_intr_handler (TMTask* task)
 {
-	swproc_all ();
-	WakeUpProcess (&g_psn);
-	PrimeTime ((QElem*)&g_tmtask, TMTASK_DELAY);
+	swproc_moo ();
+	WakeUpProcess (&mac_psn);
+	PrimeTime ((QElem*)&mac_tmtask, TMTASK_DELAY);
 }
 
-#else
-static void arrange_process_switching (int sig)
-{
-	swproc_all ();
-}
-#endif
-
 static void setup_tick (void)
 {
-#if defined(__DOS__) && (defined(_INTELC32_) || defined(__WATCOMC__))
+	GetCurrentProcess (&mac_psn);
+	memset (&mac_tmtask, 0, MOO_SIZEOF(mac_tmtask));
+	mac_tmtask.tmAddr = NewTimerProc (timer_intr_handler);
+	InsXTime ((QElem*)&mac_tmtask);
+	PrimeTime ((QElem*)&mac_tmtask, TMTASK_DELAY);
+}
 
-	prev_timer_intr_handler = _dos_getvect (0x1C);
-	_dos_setvect (0x1C, timer_intr_handler);
-
-#elif defined(_WIN32)
-
-	LARGE_INTEGER li;
-	g_tick_timer = CreateWaitableTimer(MOO_NULL, TRUE, MOO_NULL);
-	if (g_tick_timer)
-	{
-		li.QuadPart = -MOO_SECNSEC_TO_NSEC(0, 20000); /* 20000 microseconds. 0.02 seconds */
-		SetWaitableTimer (g_tick_timer, &li, 0, arrange_process_switching, MOO_NULL, FALSE);
-	}
-
-#elif defined(__OS2__)
-	/* TODO: Error check */
-	DosCreateThread (&g_tick_tid, os2_wait_for_timer_event, 0, 0, 4096);
-
-#elif defined(macintosh)
-
-	GetCurrentProcess (&g_psn);
-	MOO_MEMSET (&g_tmtask, 0, MOO_SIZEOF(g_tmtask));
-	g_tmtask.tmAddr = NewTimerProc (timer_intr_handler);
-	InsXTime ((QElem*)&g_tmtask);
-	PrimeTime ((QElem*)&g_tmtask, TMTASK_DELAY);
+static void cancel_tick (void)
+{
+	RmvTime ((QElem*)&mac_tmtask);
+	/*DisposeTimerProc (mac_tmtask.tmAddr);*/
+}
 
 #elif defined(HAVE_SETITIMER) && defined(SIGVTALRM) && defined(ITIMER_VIRTUAL)
+
+static void arrange_process_switching (int sig)
+{
+	swproc_moo ();
+}
+
+static void setup_tick (void)
+{
 	struct itimerval itv;
 	struct sigaction act;
 
-	MOO_MEMSET (&act, 0, sizeof(act));
+	memset (&act, 0, sizeof(act));
 	sigemptyset (&act.sa_mask);
 	act.sa_handler = arrange_process_switching;
 	act.sa_flags = SA_RESTART;
@@ -2759,36 +2792,10 @@ static void setup_tick (void)
 	itv.it_value.tv_sec = 0;
 	itv.it_value.tv_usec = MOO_ITIMER_TICK;
 	setitimer (ITIMER_VIRTUAL, &itv, MOO_NULL);
-#else
-
-#	error UNSUPPORTED
-#endif
 }
 
 static void cancel_tick (void)
 {
-#if defined(__DOS__) && (defined(_INTELC32_) || defined(__WATCOMC__))
-
-	_dos_setvect (0x1C, prev_timer_intr_handler);
-
-#elif defined(_WIN32)
-
-	if (g_tick_timer)
-	{
-		CancelWaitableTimer (g_tick_timer);
-		CloseHandle (g_tick_timer);
-		g_tick_timer = MOO_NULL;
-	}
-
-#elif defined(__OS2__)
-	if (g_tick_sem) DosPostEventSem (g_tick_sem);
-	g_tick_done = 1;
-
-#elif defined(macintosh)
-	RmvTime ((QElem*)&g_tmtask);
-	/*DisposeTimerProc (g_tmtask.tmAddr);*/
-
-#elif defined(HAVE_SETITIMER) && defined(SIGVTALRM) && defined(ITIMER_VIRTUAL)
 	struct itimerval itv;
 	struct sigaction act;
 
@@ -2802,12 +2809,10 @@ static void cancel_tick (void)
 	act.sa_handler = SIG_IGN; /* ignore the signal potentially fired by the one-shot arrange above */
 	act.sa_flags = 0;
 	sigaction (SIGVTALRM, &act, MOO_NULL);
-
+}
 #else
 #	error UNSUPPORTED
 #endif
-}
-
 
 /* ========================================================================= */