diff --git a/scheduler/semaphore.c b/scheduler/semaphore.c
new file mode 100644
index 0000000..d8c1535
--- /dev/null
+++ b/scheduler/semaphore.c
@@ -0,0 +1,214 @@
+/*
+ * Win32 semaphores
+ *
+ * Copyright 1998 Alexandre Julliard
+ */
+
+#include <assert.h>
+#include "windows.h"
+#include "winerror.h"
+#include "k32obj.h"
+#include "process.h"
+#include "thread.h"
+#include "heap.h"
+
+typedef struct
+{
+    K32OBJ        header;
+    THREAD_QUEUE  wait_queue;
+    LONG          count;
+    LONG          max;
+} SEMAPHORE;
+
+static BOOL32 SEMAPHORE_Signaled( K32OBJ *obj, DWORD thread_id );
+static void SEMAPHORE_Satisfied( K32OBJ *obj, DWORD thread_id );
+static void SEMAPHORE_AddWait( K32OBJ *obj, DWORD thread_id );
+static void SEMAPHORE_RemoveWait( K32OBJ *obj, DWORD thread_id );
+static void SEMAPHORE_Destroy( K32OBJ *obj );
+
+const K32OBJ_OPS SEMAPHORE_Ops =
+{
+    SEMAPHORE_Signaled,    /* signaled */
+    SEMAPHORE_Satisfied,   /* satisfied */
+    SEMAPHORE_AddWait,     /* add_wait */
+    SEMAPHORE_RemoveWait,  /* remove_wait */
+    SEMAPHORE_Destroy      /* destroy */
+};
+
+
+/***********************************************************************
+ *           CreateSemaphore32A   (KERNEL32.174)
+ */
+HANDLE32 WINAPI CreateSemaphore32A( SECURITY_ATTRIBUTES *sa, LONG initial,
+                                    LONG max, LPCSTR name )
+{
+    HANDLE32 handle;
+    SEMAPHORE *sem;
+
+    /* Check parameters */
+
+    if ((max <= 0) || (initial < 0) || (initial > max))
+    {
+        SetLastError( ERROR_INVALID_PARAMETER );
+        return INVALID_HANDLE_VALUE32;
+    }
+
+    SYSTEM_LOCK();
+    sem = (SEMAPHORE *)K32OBJ_Create( K32OBJ_SEMAPHORE, sizeof(*sem),
+                                      name, &handle );
+    if (sem)
+    {
+        /* Finish initializing it */
+        sem->wait_queue = NULL;
+        sem->count      = initial;
+        sem->max        = max;
+        K32OBJ_DecCount( &sem->header );
+    }
+    SYSTEM_UNLOCK();
+    return handle;
+}
+
+
+/***********************************************************************
+ *           CreateSemaphore32W   (KERNEL32.175)
+ */
+HANDLE32 WINAPI CreateSemaphore32W( SECURITY_ATTRIBUTES *sa, LONG initial,
+                                    LONG max, LPCWSTR name )
+{
+    LPSTR nameA = HEAP_strdupWtoA( GetProcessHeap(), 0, name );
+    HANDLE32 ret = CreateSemaphore32A( sa, initial, max, nameA );
+    if (nameA) HeapFree( GetProcessHeap(), 0, nameA );
+    return ret;
+}
+
+
+/***********************************************************************
+ *           OpenSemaphore32A   (KERNEL32.545)
+ */
+HANDLE32 WINAPI OpenSemaphore32A( DWORD access, BOOL32 inherit, LPCSTR name )
+{
+    HANDLE32 handle = 0;
+    K32OBJ *obj;
+    SYSTEM_LOCK();
+    if ((obj = K32OBJ_FindNameType( name, K32OBJ_SEMAPHORE )) != NULL)
+    {
+        handle = PROCESS_AllocHandle( obj, 0 );
+        K32OBJ_DecCount( obj );
+    }
+    SYSTEM_UNLOCK();
+    return handle;
+}
+
+
+/***********************************************************************
+ *           OpenSemaphore32W   (KERNEL32.546)
+ */
+HANDLE32 WINAPI OpenSemaphore32W( DWORD access, BOOL32 inherit, LPCWSTR name )
+{
+    LPSTR nameA = HEAP_strdupWtoA( GetProcessHeap(), 0, name );
+    HANDLE32 ret = OpenSemaphore32A( access, inherit, nameA );
+    if (nameA) HeapFree( GetProcessHeap(), 0, nameA );
+    return ret;
+}
+
+
+/***********************************************************************
+ *           ReleaseSemaphore   (KERNEL32.583)
+ */
+BOOL32 WINAPI ReleaseSemaphore( HANDLE32 handle, LONG count, LONG *previous )
+{
+    SEMAPHORE *sem;
+
+    SYSTEM_LOCK();
+    if (!(sem = (SEMAPHORE *)PROCESS_GetObjPtr( handle, K32OBJ_SEMAPHORE )))
+    {
+        SYSTEM_UNLOCK();
+        return FALSE;
+    }
+    if (previous) *previous = sem->count;
+    if (sem->count + count > sem->max)
+    {
+        SYSTEM_UNLOCK();
+        SetLastError( ERROR_TOO_MANY_POSTS );
+        return FALSE;
+    }
+    if (sem->count > 0)
+    {
+        /* There cannot be any thread waiting if the count is > 0 */
+        assert( sem->wait_queue == NULL );
+        sem->count += count;
+    }
+    else
+    {
+        sem->count = count;
+        SYNC_WakeUp( &sem->wait_queue, count );
+    }
+    K32OBJ_DecCount( &sem->header );
+    SYSTEM_UNLOCK();
+    return TRUE;
+}
+
+
+/***********************************************************************
+ *           SEMAPHORE_Signaled
+ */
+static BOOL32 SEMAPHORE_Signaled( K32OBJ *obj, DWORD thread_id )
+{
+    SEMAPHORE *sem = (SEMAPHORE *)obj;
+    assert( obj->type == K32OBJ_SEMAPHORE );
+    return (sem->count > 0);
+}
+
+
+/***********************************************************************
+ *           SEMAPHORE_Satisfied
+ *
+ * Wait on this object has been satisfied.
+ */
+static void SEMAPHORE_Satisfied( K32OBJ *obj, DWORD thread_id )
+{
+    SEMAPHORE *sem = (SEMAPHORE *)obj;
+    assert( obj->type == K32OBJ_SEMAPHORE );
+    assert( sem->count > 0 );
+    sem->count--;
+}
+
+
+/***********************************************************************
+ *           SEMAPHORE_AddWait
+ *
+ * Add current thread to object wait queue.
+ */
+static void SEMAPHORE_AddWait( K32OBJ *obj, DWORD thread_id )
+{
+    SEMAPHORE *sem = (SEMAPHORE *)obj;
+    assert( obj->type == K32OBJ_SEMAPHORE );
+    THREAD_AddQueue( &sem->wait_queue, THREAD_ID_TO_THDB(thread_id) );
+}
+
+
+/***********************************************************************
+ *           SEMAPHORE_RemoveWait
+ *
+ * Remove thread from object wait queue.
+ */
+static void SEMAPHORE_RemoveWait( K32OBJ *obj, DWORD thread_id )
+{
+    SEMAPHORE *sem = (SEMAPHORE *)obj;
+    assert( obj->type == K32OBJ_SEMAPHORE );
+    THREAD_RemoveQueue( &sem->wait_queue, THREAD_ID_TO_THDB(thread_id) );
+}
+
+
+/***********************************************************************
+ *           SEMAPHORE_Destroy
+ */
+static void SEMAPHORE_Destroy( K32OBJ *obj )
+{
+    SEMAPHORE *sem = (SEMAPHORE *)obj;
+    assert( obj->type == K32OBJ_SEMAPHORE );
+    /* There cannot be any thread on the list since the ref count is 0 */
+    assert( sem->wait_queue == NULL );
+    obj->type = K32OBJ_UNKNOWN;
+    HeapFree( SystemHeap, 0, sem );
+}