diff --git a/aos/common/condition.h b/aos/common/condition.h
index c527f34..956dc6c 100644
--- a/aos/common/condition.h
+++ b/aos/common/condition.h
@@ -1,60 +1,41 @@
 #ifndef AOS_COMMON_CONDITION_H_
 #define AOS_COMMON_CONDITION_H_
 
-#ifdef __VXWORKS__
-#include <semLib.h>
-#endif
-
-#include "aos/aos_core.h"
 #include "aos/common/mutex.h"
+#include "aos/atom_code/ipc_lib/aos_sync.h"
 
 namespace aos {
 
 // A condition variable (IPC mechanism where 1 process/task can notify all
 // others that are waiting for something to happen).
-// There are implementations for both the atom and the cRIO.
-// They both LOG(FATAL) if anything weird happens.
+// This implementation will LOG(FATAL) if anything weird happens.
 //
-// A condition is either set or unset, and multiple processes/tasks can wait on
-// one for it to be set.
+// Multiple condition variables may be associated with the same mutex but
+// exactly 1 mutex must be associated with each condition variable.
 class Condition {
  public:
-  // Creates an unset condition.
-  Condition();
-#ifdef __VXWORKS__
-  // Will not make sure that it is either set or unset.
-  ~Condition();
-#endif
-  // Waits for the condition to be set. Will return true immediately if it is
-  // already set.
-  // Returns false if returning before a confirmed condition set, although doing
-  // anything very useful with the return value is difficult because the
-  // condition may have been set (and possibly even unset again) between the
-  // time when the system call to block returned and this function returns.
-  bool Wait();
-  // Waits for the next Set(), regardless of whether or not the condition is
-  // currently set.
-  // Same return value as Wait().
-  bool WaitNext();
+  // m is the mutex that will be associated with this condition variable.
+  explicit Condition(Mutex *m);
 
-  // Sets the condition. Any processes/tasks that are currently Wait()ing will
-  // continue.
-  // All implementations will wake all waiting processes/tasks at once so that
-  // the highest priority one(s) will run before others like usual.
-  void Set();
-  // Unsets the condition.
-  void Unset();
+  // Waits for the condition variable to be signalled, atomically unlocking m at
+  // the same time. The mutex associated with this condition variable must be
+  // locked when this is called and will be locked when this method returns.
+  void Wait();
+
+  // Signals at most 1 other process currently Wait()ing on this condition
+  // variable. Calling this does not require the mutex associated with this
+  // condition variable to be locked.
+  // One of the processes with the highest priority level will be woken if there
+  // are multiple ones.
+  void Signal();
+  // Wakes all processes that are currently Wait()ing on this condition
+  // variable. Calling this does not require the mutex associated with this
+  // condition variable to be locked.
+  void Broadcast();
 
  private:
-#ifdef __VXWORKS__
-  // Always empty. Used to make tasks wait and then gets flushed to unblock all
-  // of them.
-  SEM_ID wait_;
-  // Whether or not the conditon is set.
-  bool set_;
-#else
-  mutex impl_;
-#endif
+  condition_variable impl_;
+  Mutex *m_;
 };
 
 }  // namespace aos