diff --git a/kernel/sched.c b/kernel/sched.c
index 0320f36d08d6d8094859aa1b7c951ce737aa367b..e279768f2805ddebf4530c90e68ece225fffab52 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -61,7 +61,50 @@ void schedule() {
     switch_to(next);
 }
 
-int clock = COUNTER;
+static inline void __sleep_on(struct task_struct** p, int state) {
+    struct task_struct* tmp;
+
+    if (!p)
+        return;
+    if (current == &(init_task.task))
+        printk("task[0] trying to sleep");
+
+    tmp = *p;
+    *p = current;
+    current->state = state;
+
+repeat:
+    schedule();
+
+    if (*p && *p != current) {
+        (**p).state = 0;
+        current->state = TASK_UNINTERRUPTIBLE;
+        goto repeat;
+    }
+
+    if (!*p)
+        printk("Warning: *P = NULL\n\r");
+    if (*p = tmp)
+        tmp->state = 0;
+}
+
+void interruptible_sleep_on(struct task_struct** p) {
+    __sleep_on(p, TASK_INTERRUPTIBLE);
+}
+
+void sleep_on(struct task_struct** p) {
+    __sleep_on(p, TASK_UNINTERRUPTIBLE);
+}
+
+void wake_up(struct task_struct **p) {
+    if (p && *p) {
+        if ((**p).state == TASK_STOPPED)
+            printk("wake_up: TASK_STOPPED");
+        if ((**p).state == TASK_ZOMBIE)
+            printk("wake_up: TASK_ZOMBIE");
+        (**p).state=0;
+    }
+}
 
 void do_timer(long cpl) {
     if ((--current->counter)>0) return;