diff --git a/AppKit/fifo.h b/AppKit/fifo.h
index 576caf5..0794224 100644
--- a/AppKit/fifo.h
+++ b/AppKit/fifo.h
@@ -48,6 +48,7 @@ void fifo_clear(fifo_t* self){
     self->read_idx = self->write_idx = 0;
 }
 
+
 OS_STATIC_FORCE_INLINE
 os_bool_t fifo_is_empty(fifo_t* self){
     return (self->write_idx==self->read_idx);
diff --git a/AppKit/gai_action.c b/AppKit/gai_action.c
new file mode 100644
index 0000000..56f7775
--- /dev/null
+++ b/AppKit/gai_action.c
@@ -0,0 +1 @@
+#include <gai_action.h>
diff --git a/AppKit/gai_action.h b/AppKit/gai_action.h
new file mode 100644
index 0000000..3266008
--- /dev/null
+++ b/AppKit/gai_action.h
@@ -0,0 +1,81 @@
+#ifndef INCLUDED_GAI_ACTION_H
+#define INCLUDED_GAI_ACTION_H
+
+#ifndef INCLUDED_OS_TYPES_H
+#include <os_types.h>
+#endif /*INCLUDED_OS_TYPES_H*/
+
+#ifndef INCLUDED_OS_COMPILER_H
+#include <os_compiler.h>
+#endif /*INCLUDED_OS_COMPILER_H*/
+
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+typedef struct gai_action_t gai_action_t;
+typedef void (*gai_action_function_t)(gai_action_t* self);
+typedef void (*gai_action_update_function_t)(gai_action_t* self, void* params);
+
+typedef enum {
+    kGaiActionStatus_UnInitialized=0,
+    kGaiActionStatus_Running,
+    kGaiActionStatus_Terminated,
+}gai_action_status_t;
+
+struct gai_action_t{
+    gai_action_status_t status;
+    gai_action_function_t onInitialize;
+    gai_action_update_function_t onUpdate;
+    gai_action_function_t onCleanup;
+    void* userdata;
+};
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+OS_STATIC_FORCE_INLINE
+void gai_action_init(gai_action_t* self,
+                     gai_action_function_t onInitialize,
+                     gai_action_update_function_t onUpdate,
+                     gai_action_function_t onCleanup, void* userdata){
+    self->status = kGaiActionStatus_UnInitialized;
+    self->onInitialize = onInitialize;
+    self->onUpdate = onUpdate;
+    self->onCleanup = onCleanup;
+    self->userdata = userdata;
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_action_Initialize(gai_action_t* self){
+    if(self->onInitialize){
+        self->onInitialize(self);
+    }
+    self->status = kGaiActionStatus_Running;
+}
+
+OS_STATIC_FORCE_INLINE
+gai_action_status_t gai_action_Update(gai_action_t* self, void* userdata){
+    if(self->status==kGaiActionStatus_Terminated){
+        return kGaiActionStatus_Terminated;
+    }
+    if(self->onUpdate){
+        self->onUpdate(self, userdata);
+    }else{
+        self->status = kGaiActionStatus_Terminated;
+    }
+    return self->status;
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_action_Cleanup(gai_action_t* self){
+    if(self->status == kGaiActionStatus_Terminated){
+        if(self->onCleanup){
+            self->onCleanup(self);
+        }
+    }
+    self->status = kGaiActionStatus_UnInitialized;
+}
+
+
+#endif /*INCLUDED_GAI_ACTION_H*/
diff --git a/AppKit/gai_fsm.c b/AppKit/gai_fsm.c
new file mode 100644
index 0000000..4405658
--- /dev/null
+++ b/AppKit/gai_fsm.c
@@ -0,0 +1,31 @@
+#include <gai_fsm.h>
+
+static os_int_t FindNextState(gai_fsm_t* self, os_list_t* transitions, void* ud){
+    os_list_node_t * p_node = 0;
+    for(p_node = transitions->next; p_node!=transitions; p_node= p_node->next){
+        gai_fsm_transition_t* p_transition = os_list_member_of(p_node, gai_fsm_transition_t, node);
+        if(p_transition->evaluator(self, p_transition, ud)){
+            return p_transition->to_state_id;
+        }
+    }
+    return -1;
+}
+
+void gai_fsm_update(gai_fsm_t* self, void* userdata){
+    if(!self->current_state_p){
+        return;
+    }
+    gai_action_status_t status = gai_fsm_status(self);
+    if(status==kGaiActionStatus_Running){
+        gai_action_Update(&self->current_state_p->action, userdata);
+    }else if(status==kGaiActionStatus_Terminated){
+        os_int_t to_state_id = FindNextState(self, &self->current_state_p->transition_list, userdata);
+        gai_fsm_state_t* p_next_state = gai_fsm_find_state(self, to_state_id);
+        if(p_next_state){
+            gai_action_Cleanup(&self->current_state_p->action);
+            self->current_state_p = p_next_state;
+            gai_action_Initialize(&self->current_state_p->action);
+        }
+    }
+}
+
diff --git a/AppKit/gai_fsm.h b/AppKit/gai_fsm.h
new file mode 100644
index 0000000..2d9bffd
--- /dev/null
+++ b/AppKit/gai_fsm.h
@@ -0,0 +1,180 @@
+#ifndef INCLUDED_GAI_FSM_H
+#define INCLUDED_GAI_FSM_H
+
+#ifndef INCLUDED_OS_TYPES_H
+#include <os_types.h>
+#endif /*INCLUDED_OS_TYPES_H*/
+
+#ifndef INCLUDED_OS_COMPILER_H
+#include <os_compiler.h>
+#endif /*INCLUDED_OS_COMPILER_H*/
+
+#ifndef INCLUDED_OS_LIST_H
+#include <os_list.h>
+#endif /*INCLUDED_OS_LIST_H*/
+
+#ifndef INCLUDED_GAI_ACTION_H
+#include <gai_action.h>
+#endif /*INCLUDED_GAI_ACTION_H*/
+
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+typedef struct gai_fsm_state_t gai_fsm_state_t;
+typedef struct gai_fsm_transition_t gai_fsm_transition_t;
+typedef struct gai_fsm_t gai_fsm_t;
+
+typedef os_bool_t (*gai_fsm_evaluator_t)(gai_fsm_t* self, gai_fsm_transition_t* transition, void* ud);
+
+struct gai_fsm_state_t{
+    os_list_node_t      node;
+    os_int_t            id;
+    os_list_t           transition_list;
+    gai_action_t        action;
+};
+
+struct gai_fsm_transition_t{
+    os_list_node_t      node;
+    os_int_t            from_state_id;
+    os_int_t            to_state_id;
+    gai_fsm_evaluator_t evaluator;
+    void* userdata;
+};
+
+struct gai_fsm_t{
+    gai_fsm_state_t*    current_state_p;
+    os_list_t           state_list;
+    void* userdata;
+};
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_init(gai_fsm_t* self, void* userdata){
+    self->current_state_p = 0;
+    os_list_init(&self->state_list);
+    self->userdata = userdata;
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_add_state(gai_fsm_t* self, gai_fsm_state_t * state){
+    os_list_insert_after(&self->state_list, &state->node);
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_add_transition(gai_fsm_t* self, gai_fsm_transition_t* transition){
+    os_list_node_t* p_node;
+    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
+        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
+        if(transition->from_state_id != p_state->id){
+            continue;
+        }
+        os_list_insert_after(&p_state->transition_list, &transition->node);
+        break;
+    }
+}
+
+
+OS_STATIC_FORCE_INLINE
+gai_action_status_t gai_fsm_status(gai_fsm_t* self){
+    if(self->current_state_p){
+        return self->current_state_p->action.status;
+    }
+    return kGaiActionStatus_UnInitialized;
+}
+
+
+OS_STATIC_FORCE_INLINE
+gai_fsm_transition_t* gai_fsm_find_transition(gai_fsm_t* self, os_int_t from_state_id, os_int_t to_state_id){
+    gai_fsm_state_t * p_from_state = 0;
+    os_list_node_t* p_node;
+    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
+        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
+        if(p_state->id==from_state_id){
+            p_from_state = p_state;
+            break;
+        }
+    }
+    if(p_from_state==0){
+        return 0;
+    }
+    for(p_node = p_from_state->transition_list.next; p_node!=&p_from_state->transition_list; p_node= p_node->next){
+        gai_fsm_transition_t* p_transition = os_list_member_of(p_node, gai_fsm_transition_t, node);
+        if(p_transition->to_state_id == to_state_id){
+            return p_transition;
+        }
+    }
+    return 0;
+}
+
+OS_STATIC_FORCE_INLINE
+gai_fsm_state_t* gai_fsm_find_state(gai_fsm_t* self, os_int_t state_id){
+    os_list_node_t* p_node;
+    for(p_node = self->state_list.next; p_node!=&self->state_list; p_node = p_node->next){
+        gai_fsm_state_t* p_state = os_list_member_of(p_node, gai_fsm_state_t, node);
+        if(p_state->id==state_id){
+            return p_state;
+        }
+    }
+    return 0;
+}
+
+
+OS_STATIC_FORCE_INLINE
+os_bool_t gai_fsm_has_transition(gai_fsm_t* self, os_int_t from_state_id, os_int_t to_state_id){
+    return (gai_fsm_find_transition(self, from_state_id, to_state_id)!=0)?OS_TRUE:OS_FALSE;
+}
+
+
+OS_STATIC_FORCE_INLINE
+os_bool_t gai_fsm_has_state(gai_fsm_t* self, os_int_t state_id){
+    return (gai_fsm_find_state(self, state_id)!=0)?OS_TRUE:OS_FALSE;
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_set_state(gai_fsm_t* self, os_int_t state_id){
+    gai_fsm_state_t* p_state = gai_fsm_find_state(self, state_id);
+    if(p_state==0){
+        return;
+    }
+    gai_action_Cleanup(&p_state->action);
+    self->current_state_p = p_state;
+    gai_action_Initialize(&p_state->action);
+}
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_state_init(gai_fsm_state_t* self, os_int_t id,
+                        gai_action_function_t onInitialize,
+                        gai_action_update_function_t onUpdate,
+                        gai_action_function_t onCleanup, void* userdata){
+    os_list_init(&self->node);
+    self->id = id;
+    os_list_init(&self->transition_list);
+    gai_action_init(&self->action, onInitialize, onUpdate, onCleanup, userdata);
+}
+
+OS_STATIC_FORCE_INLINE
+void gai_fsm_transition_init(gai_fsm_transition_t* self,
+                             os_int_t from_state_id,
+                             os_int_t to_state_id,
+                             gai_fsm_evaluator_t evaluator,
+                             void* userdata){
+    self->evaluator = evaluator;
+    self->from_state_id = from_state_id;
+    self->to_state_id = to_state_id;
+    os_list_init(&self->node);
+    self->userdata = userdata;
+}
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+
+void gai_fsm_update(gai_fsm_t* self, void* userdata);
+
+#endif /*INCLUDED_GAI_FSM_H*/
diff --git a/Kernel/SingleCore/os_systick.h b/Kernel/SingleCore/os_systick.h
index a488b4c..60e6af3 100644
--- a/Kernel/SingleCore/os_systick.h
+++ b/Kernel/SingleCore/os_systick.h
@@ -69,10 +69,13 @@ void os_systick_tick(void){
 
 OS_STATIC_FORCE_INLINE
 os_tick_t os_systick_get(void){
+#if 0
     os_critical_enter();
     os_tick_t ticks =  g_os_systick_ticks;
     os_critical_leave();
     return ticks;
+#endif
+    return g_os_systick_ticks;
 }