diff --git a/demos/STM32/NIL-STM32F303-DISCOVERY/Makefile b/demos/STM32/NIL-STM32F303-DISCOVERY/Makefile
index 631095137..bca2377d7 100644
--- a/demos/STM32/NIL-STM32F303-DISCOVERY/Makefile
+++ b/demos/STM32/NIL-STM32F303-DISCOVERY/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O0 -ggdb -fomit-frame-pointer -falign-functions=16
+  USE_OPT = -O2 -ggdb -fomit-frame-pointer -falign-functions=16
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/demos/STM32/NIL-STM32L476-DISCOVERY/cfg/chconf.h b/demos/STM32/NIL-STM32L476-DISCOVERY/cfg/chconf.h
index e0dca22c5..bd2e50a45 100644
--- a/demos/STM32/NIL-STM32L476-DISCOVERY/cfg/chconf.h
+++ b/demos/STM32/NIL-STM32L476-DISCOVERY/cfg/chconf.h
@@ -130,6 +130,15 @@
  */
 #define CH_CFG_USE_EVENTS                   TRUE
 
+/**
+ * @brief   Synchronous Messages APIs.
+ * @details If enabled then the synchronous messages APIs are included
+ *          in the kernel.
+ *
+ * @note    The default is @p TRUE.
+ */
+#define CH_CFG_USE_MESSAGES                 TRUE
+
 /**
  * @brief   Mailboxes APIs.
  * @details If enabled then the asynchronous messages (mailboxes) APIs are
diff --git a/os/nil/include/ch.h b/os/nil/include/ch.h
index 75a89766f..fb98aedad 100644
--- a/os/nil/include/ch.h
+++ b/os/nil/include/ch.h
@@ -31,8 +31,6 @@
 #define CH_H
 
 #include "chtypes.h"
-#include "chconf.h"
-#include "chlicense.h"
 
 /*===========================================================================*/
 /* Module constants.                                                         */
@@ -147,7 +145,11 @@
 #define NIL_STATE_WTQUEUE       (tstate_t)5 /**< @brief On queue or semaph. */
 #define NIL_STATE_WTOREVT       (tstate_t)6 /**< @brief Waiting for events. */
 #define NIL_STATE_WTANDEVT      (tstate_t)7 /**< @brief Waiting for events. */
-#define NIL_STATE_FINAL         (tstate_t)8 /**< @brief Thread terminated.  */
+#define NIL_STATE_SNDMSGQ       (tstate_t)8 /**< @brief Sending a message,
+                                                        in queue.           */
+#define NIL_STATE_WTMSG         (tstate_t)10/**< @brief Waiting for a
+                                                        message.            */
+#define NIL_STATE_FINAL         (tstate_t)11/**< @brief Thread terminated.  */
 
 #define NIL_THD_IS_WTSTART(tp)      ((tp)->state == NIL_STATE_WTSTART)
 #define NIL_THD_IS_READY(tp)        ((tp)->state == NIL_STATE_READY)
@@ -157,343 +159,115 @@
 #define NIL_THD_IS_WTQUEUE(tp)      ((tp)->state == NIL_STATE_WTQUEUE)
 #define NIL_THD_IS_WTOREVT(tp)      ((tp)->state == NIL_STATE_WTOREVT)
 #define NIL_THD_IS_WTANDEVT(tp)     ((tp)->state == NIL_STATE_WTANDEVT)
+#define NIL_THD_IS_SNDMSGQ(tp)      ((tp)->state == NIL_STATE_SNDMSGQ)
+#define NIL_THD_IS_WTMSG(tp)        ((tp)->state == NIL_STATE_WTMSG)
 #define NIL_THD_IS_FINAL(tp)        ((tp)->state == NIL_STATE_FINAL)
 
 #define CH_STATE_NAMES                                                      \
   "WTSTART", "READY", "SLEEPING", "SUSPENDED", "WTEXIT", "WTQUEUE",         \
-  "WTOREVT", "WTANDEVT", "FINAL"
-/** @} */
-
-/**
- * @name    Events related macros
- * @{
- */
-/**
- * @brief   All events allowed mask.
- */
-#define ALL_EVENTS              ((eventmask_t)-1)
-
-/**
- * @brief   Returns an event mask from an event identifier.
- */
-#define EVENT_MASK(eid)         ((eventmask_t)(1 << (eid)))
+  "WTOREVT", "WTANDEVT", "SNDMSGQ", "SNDMSG", "WTMSG", "FINAL"
 /** @} */
 
 /*===========================================================================*/
 /* Module pre-compile time settings.                                         */
 /*===========================================================================*/
 
-/*-*
- * @brief   Maximum number of user threads in the application.
- * @note    This number is not inclusive of the idle thread which is
- *          implicitly handled.
- * @note    Set this value to be exactly equal to the number of threads you
- *          will use or you would be wasting RAM and cycles.
- * @note    This values also defines the number of available priorities
- *          (0..CH_CFG_MAX_THREADS-1).
- */
-#if !defined(CH_CFG_MAX_THREADS) || defined(__DOXYGEN__)
-#define CH_CFG_MAX_THREADS                  2
-#endif
-
-/*-*
- * @brief   Auto starts threads when @p chSysInit() is invoked.
- */
-#if !defined(CH_CFG_AUTOSTART_THREADS) || defined(__DOXYGEN__)
-#define CH_CFG_AUTOSTART_THREADS            TRUE
-#endif
-
-/*-*
- * @brief   System time counter resolution.
- * @note    Allowed values are 16 or 32 bits.
- */
-#if !defined(CH_CFG_ST_RESOLUTION) || defined(__DOXYGEN__)
-#define CH_CFG_ST_RESOLUTION                32
-#endif
-
-/*-*
- * @brief   System tick frequency.
- * @note    This value together with the @p CH_CFG_ST_RESOLUTION
- *          option defines the maximum amount of time allowed for
- *          timeouts.
- */
-#if !defined(CH_CFG_ST_FREQUENCY) || defined(__DOXYGEN__)
-#define CH_CFG_ST_FREQUENCY                 100
-#endif
-
-/*-*
- * @brief   Time delta constant for the tick-less mode.
- * @note    If this value is zero then the system uses the classic
- *          periodic tick. This value represents the minimum number
- *          of ticks that is safe to specify in a timeout directive.
- *          The value one is not valid, timeouts are rounded up to
- *          this value.
- */
-#if !defined(CH_CFG_ST_TIMEDELTA) || defined(__DOXYGEN__)
-#define CH_CFG_ST_TIMEDELTA                 0
-#endif
-
-/*-*
- * @brief   Threads synchronization APIs.
- * @details If enabled then the @p chThdWait() function is included in
- *          the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_WAITEXIT)
-#define CH_CFG_USE_WAITEXIT                 TRUE
-#endif
-
-/*-*
- * @brief   Semaphores APIs.
- * @details If enabled then the Semaphores APIs are included in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_SEMAPHORES) || defined(__DOXYGEN__)
-#define CH_CFG_USE_SEMAPHORES               TRUE
-#endif
-
-/*-*
- * @brief   Mutexes APIs.
- * @details If enabled then the mutexes APIs are included in the kernel.
- *
- * @note    Feature not currently implemented.
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_CFG_USE_MUTEXES) || defined(__DOXYGEN__)
-#define CH_CFG_USE_MUTEXES                  FALSE
-#endif
-
-/*-*
- * @brief   Events Flags APIs.
- * @details If enabled then the event flags APIs are included in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_EVENTS) || defined(__DOXYGEN__)
-#define CH_CFG_USE_EVENTS                   TRUE
-#endif
-
-/*-*
- * @brief   Mailboxes APIs.
- * @details If enabled then the asynchronous messages (mailboxes) APIs are
- *          included in the kernel.
- *
- * @note    The default is @p TRUE.
- * @note    Requires @p CH_CFG_USE_SEMAPHORES.
- */
-#if !defined(CH_CFG_USE_MAILBOXES) || defined(__DOXYGEN__)
-#define CH_CFG_USE_MAILBOXES                TRUE
-#endif
-
-/*-*
- * @brief   Core Memory Manager APIs.
- * @details If enabled then the core memory manager APIs are included
- *          in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_MEMCORE) || defined(__DOXYGEN__)
-#define CH_CFG_USE_MEMCORE                  TRUE
-#endif
-
-/*-*
- * @brief   Heap Allocator APIs.
- * @details If enabled then the memory heap allocator APIs are included
- *          in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_HEAP) || defined(__DOXYGEN__)
-#define CH_CFG_USE_HEAP                     TRUE
-#endif
-
-/*-*
- * @brief   Memory Pools Allocator APIs.
- * @details If enabled then the memory pools allocator APIs are included
- *          in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_MEMPOOLS) || defined(__DOXYGEN__)
-#define CH_CFG_USE_MEMPOOLS                 TRUE
-#endif
-
-/*-*
- * @brief   Objects Factory APIs.
- * @details If enabled then the objects factory APIs are included in the
- *          kernel.
- *
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_CFG_USE_FACTORY) || defined(__DOXYGEN__)
-#define CH_CFG_USE_FACTORY                  TRUE
-#endif
-
-/*-*
- * @brief   Maximum length for object names.
- * @details If the specified length is zero then the name is stored by
- *          pointer but this could have unintended side effects.
- */
-#if !defined(CH_CFG_FACTORY_MAX_NAMES_LENGTH) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_MAX_NAMES_LENGTH     8
-#endif
-
-/*-*
- * @brief   Enables the registry of generic objects.
- */
-#if !defined(CH_CFG_FACTORY_OBJECTS_REGISTRY) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_OBJECTS_REGISTRY     TRUE
-#endif
-
-/*-*
- * @brief   Enables factory for generic buffers.
- */
-#if !defined(CH_CFG_FACTORY_GENERIC_BUFFERS) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_GENERIC_BUFFERS      TRUE
-#endif
-
-/*-*
- * @brief   Enables factory for semaphores.
- */
-#if !defined(CH_CFG_FACTORY_SEMAPHORES) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_SEMAPHORES           TRUE
-#endif
-
-/*-*
- * @brief   Enables factory for mailboxes.
- */
-#if !defined(CH_CFG_FACTORY_MAILBOXES) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_MAILBOXES            TRUE
-#endif
-
-/*-*
- * @brief   Enables factory for objects FIFOs.
- */
-#if !defined(CH_CFG_FACTORY_OBJ_FIFOS) || defined(__DOXYGEN__)
-#define CH_CFG_FACTORY_OBJ_FIFOS            TRUE
-#endif
-
-/*-*
- * @brief   Pipes APIs.
- * @details If enabled then the pipes APIs are included
- *          in the kernel.
- *
- * @note    The default is @p TRUE.
- */
-#if !defined(CH_CFG_USE_PIPES) || defined(__DOXYGEN__)
-#define CH_CFG_USE_PIPES                    TRUE
-#endif
-
-/*-*
- * @brief   Debug option, kernel statistics.
- *
- * @note    Feature not currently implemented.
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_DBG_STATISTICS) || defined(__DOXYGEN__)
-#define CH_DBG_STATISTICS                   FALSE
-#endif
-
-/*-*
- * @brief   Debug option, system state check.
- * @note    This is a planned feature, not yet implemented.
- *
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_DBG_SYSTEM_STATE_CHECK) || defined(__DOXYGEN__)
-#define CH_DBG_SYSTEM_STATE_CHECK           FALSE
-#endif
-
-/*-*
- * @brief   Debug option, parameters checks.
- *
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_DBG_ENABLE_CHECKS) || defined(__DOXYGEN__)
-#define CH_DBG_ENABLE_CHECKS                FALSE
-#endif
-
-/*-*
- * @brief   System assertions.
- *
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_DBG_ENABLE_ASSERTS) || defined(__DOXYGEN__)
-#define CH_DBG_ENABLE_ASSERTS               FALSE
-#endif
-
-/*-*
- * @brief   Stack check.
- *
- * @note    The default is @p FALSE.
- */
-#if !defined(CH_DBG_ENABLE_STACK_CHECK) || defined(__DOXYGEN__)
-#define CH_DBG_ENABLE_STACK_CHECK           FALSE
-#endif
-
-/*-*
- * @brief   System initialization hook.
- */
-#if !defined(CH_CFG_SYSTEM_INIT_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_SYSTEM_INIT_HOOK() {}
-#endif
-
-/*-*
- * @brief   Threads descriptor structure extension.
- * @details User fields added to the end of the @p thread_t structure.
- */
-#if !defined(CH_CFG_THREAD_EXT_FIELDS) || defined(__DOXYGEN__)
-#define CH_CFG_THREAD_EXT_FIELDS
-#endif
-
-/*-*
- * @brief   Threads initialization hook.
- */
-#if !defined(CH_CFG_THREAD_EXT_INIT_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_THREAD_EXT_INIT_HOOK(tp) {}
-#endif
-
-/*-*
- * @brief   Threads finalization hook.
- * @details User finalization code added to the @p chThdExit() API.
- */
-#if !defined(CH_CFG_THREAD_EXIT_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_THREAD_EXIT_HOOK(tp) {}
-#endif
-
-/*-*
- * @brief   Idle thread enter hook.
- * @note    This hook is invoked within a critical zone, no OS functions
- *          should be invoked from here.
- * @note    This macro can be used to activate a power saving mode.
- */
-#if !defined(CH_CFG_IDLE_ENTER_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_IDLE_ENTER_HOOK() {}
-#endif
-
-/*-*
- * @brief   Idle thread leave hook.
- * @note    This hook is invoked within a critical zone, no OS functions
- *          should be invoked from here.
- * @note    This macro can be used to deactivate a power saving mode.
- */
-#if !defined(CH_CFG_IDLE_LEAVE_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_IDLE_LEAVE_HOOK() {}
-#endif
-
-/*-*
- * @brief   System halt hook.
- */
-#if !defined(CH_CFG_SYSTEM_HALT_HOOK) || defined(__DOXYGEN__)
-#define CH_CFG_SYSTEM_HALT_HOOK(reason) {}
-#endif
+#include "chconf.h"
+#include "chlicense.h"
 
 /*===========================================================================*/
 /* Derived constants and error checks.                                       */
 /*===========================================================================*/
 
+/* Checks on configuration options.*/
+#if !defined(CH_CFG_MAX_THREADS) || defined(__DOXYGEN__)
+#error "CH_CFG_MAX_THREADS not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_AUTOSTART_THREADS) || defined(__DOXYGEN__)
+#error "CH_CFG_AUTOSTART_THREADS not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_ST_RESOLUTION) || defined(__DOXYGEN__)
+#error "CH_CFG_ST_RESOLUTION not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_ST_FREQUENCY) || defined(__DOXYGEN__)
+#error "CH_CFG_ST_FREQUENCY not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_ST_TIMEDELTA) || defined(__DOXYGEN__)
+#error "CH_CFG_ST_TIMEDELTA not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_USE_WAITEXIT)
+#error "CH_CFG_USE_WAITEXIT not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_USE_MESSAGES) || defined(__DOXYGEN__)
+#error "CH_CFG_USE_MESSAGES not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_USE_SEMAPHORES) || defined(__DOXYGEN__)
+#error "CH_CFG_USE_SEMAPHORES not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_USE_EVENTS)
+#error "CH_CFG_USE_EVENTS not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_USE_MUTEXES) || defined(__DOXYGEN__)
+#error "CH_CFG_USE_MUTEXES not defined in chconf.h"
+#endif
+
+#if !defined(CH_DBG_STATISTICS) || defined(__DOXYGEN__)
+#error "CH_DBG_STATISTICS not defined in chconf.h"
+#endif
+
+#if !defined(CH_DBG_SYSTEM_STATE_CHECK) || defined(__DOXYGEN__)
+#error "CH_DBG_SYSTEM_STATE_CHECK not defined in chconf.h"
+#endif
+
+#if !defined(CH_DBG_ENABLE_CHECKS) || defined(__DOXYGEN__)
+#error "CH_DBG_ENABLE_CHECKS not defined in chconf.h"
+#endif
+
+#if !defined(CH_DBG_ENABLE_ASSERTS) || defined(__DOXYGEN__)
+#error "CH_DBG_ENABLE_ASSERTS not defined in chconf.h"
+#endif
+
+#if !defined(CH_DBG_ENABLE_STACK_CHECK) || defined(__DOXYGEN__)
+#error "CH_DBG_ENABLE_STACK_CHECK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_SYSTEM_INIT_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_SYSTEM_INIT_HOOK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_THREAD_EXT_FIELDS) || defined(__DOXYGEN__)
+#error "CH_CFG_THREAD_EXT_FIELDS not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_THREAD_EXT_INIT_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_THREAD_EXT_INIT_HOOK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_THREAD_EXIT_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_THREAD_EXIT_HOOK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_IDLE_ENTER_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_IDLE_ENTER_HOOK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_IDLE_LEAVE_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_IDLE_LEAVE_HOOK not defined in chconf.h"
+#endif
+
+#if !defined(CH_CFG_SYSTEM_HALT_HOOK) || defined(__DOXYGEN__)
+#error "CH_CFG_SYSTEM_HALT_HOOK not defined in chconf.h"
+#endif
+
 /* License checks.*/
 #if !defined(CH_CUSTOMER_LIC_NIL) || !defined(CH_LICENSE_FEATURES)
 #error "malformed chlicense.h"
@@ -707,6 +481,9 @@ struct nil_thread {
 #if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
   eventmask_t           epmask;     /**< @brief Pending events mask.        */
 #endif
+#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
+  msg_t                 sntmsg;     /**< @brief Sent message.               */
+#endif
 #if (CH_DBG_ENABLE_STACK_CHECK == TRUE) || defined(__DOXYGEN__)
   stkalign_t            *wabase;    /**< @brief Thread stack boundary.      */
 #endif
@@ -1355,75 +1132,6 @@ struct nil_system {
  */
 #define chThdQueueIsEmptyI(tqp) ((bool)(tqp->cnt >= (cnt_t)0))
 
-#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
-/**
- * @brief   Initializes a semaphore with the specified counter value.
- *
- * @param[out] sp       pointer to a @p semaphore_t structure
- * @param[in] n         initial value of the semaphore counter. Must be
- *                      non-negative.
- *
- * @init
- */
-#define chSemObjectInit(sp, n) ((sp)->cnt = n)
-
-/**
- * @brief   Performs a wait operation on a semaphore.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @return              A message specifying how the invoking thread has been
- *                      released from the semaphore.
- * @retval CH_MSG_OK   if the thread has not stopped on the semaphore or the
- *                      semaphore has been signaled.
- * @retval CH_MSG_RST  if the semaphore has been reset using @p chSemReset().
- *
- * @api
- */
-#define chSemWait(sp) chSemWaitTimeout(sp, TIME_INFINITE)
-
-/**
- * @brief   Performs a wait operation on a semaphore.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @return              A message specifying how the invoking thread has been
- *                      released from the semaphore.
- * @retval CH_MSG_OK   if the thread has not stopped on the semaphore or the
- *                      semaphore has been signaled.
- * @retval CH_MSG_RST  if the semaphore has been reset using @p chSemReset().
- *
- * @sclass
- */
-#define chSemWaitS(sp) chSemWaitTimeoutS(sp, TIME_INFINITE)
-
-/**
- * @brief   Decreases the semaphore counter.
- * @details This macro can be used when the counter is known to be positive.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- *
- * @iclass
- */
-#define chSemFastWaitI(sp) ((sp)->cnt--)
-
-/**
- * @brief   Increases the semaphore counter.
- * @details This macro can be used when the counter is known to be not
- *          negative.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- *
- * @iclass
- */
-#define chSemFastSignalI(sp) ((sp)->cnt++)
-
-/**
- * @brief   Returns the semaphore counter current value.
- *
- * @iclass
- */
-#define chSemGetCounterI(sp) ((sp)->cnt)
-#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
-
 /**
  * @brief   Current system time.
  * @details Returns the number of system ticks since the @p chSysInit()
@@ -1576,6 +1284,8 @@ extern const thread_config_t nil_thd_configs[];
 #ifdef __cplusplus
 extern "C" {
 #endif
+  thread_t *nil_find_thread(tstate_t state, void *p);
+  cnt_t nil_ready_all(void *p, cnt_t cnt, msg_t msg);
   void chSysInit(void);
   void chSysHalt(const char *reason);
   void chSysTimerHandlerI(void);
@@ -1605,20 +1315,6 @@ extern "C" {
   void chThdDoDequeueNextI(threads_queue_t *tqp, msg_t msg);
   void chThdDequeueNextI(threads_queue_t *tqp, msg_t msg);
   void chThdDequeueAllI(threads_queue_t *tqp, msg_t msg);
-#if CH_CFG_USE_SEMAPHORES == TRUE
-  msg_t chSemWaitTimeout(semaphore_t *sp, sysinterval_t timeout);
-  msg_t chSemWaitTimeoutS(semaphore_t *sp, sysinterval_t timeout);
-  void chSemSignal(semaphore_t *sp);
-  void chSemSignalI(semaphore_t *sp);
-  void chSemReset(semaphore_t *sp, cnt_t n);
-  void chSemResetI(semaphore_t *sp, cnt_t n);
-#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
-#if CH_CFG_USE_EVENTS == TRUE
-  void chEvtSignal(thread_t *tp, eventmask_t mask);
-  void chEvtSignalI(thread_t *tp, eventmask_t mask);
-  eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, sysinterval_t timeout);
-  eventmask_t chEvtWaitAllTimeout(eventmask_t mask, sysinterval_t timeout);
-#endif
 #if CH_DBG_SYSTEM_STATE_CHECK == TRUE
   void _dbg_check_disable(void);
   void _dbg_check_suspend(void);
@@ -1636,7 +1332,10 @@ extern "C" {
 }
 #endif
 
-/* OSLIB.*/
+/* Optional modules.*/
+#include "chsem.h"
+#include "chevt.h"
+#include "chmsg.h"
 #include "chlib.h"
 
 #endif /* CH_H */
diff --git a/os/nil/include/chevt.h b/os/nil/include/chevt.h
new file mode 100644
index 000000000..10309c462
--- /dev/null
+++ b/os/nil/include/chevt.h
@@ -0,0 +1,87 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/include/chevt.h
+ * @brief   Nil RTOS events header file.
+ *
+ * @addtogroup NIL_EVENTS
+ * @{
+ */
+
+#ifndef CHEVT_H
+#define CHEVT_H
+
+#if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module constants.                                                         */
+/*===========================================================================*/
+
+/**
+ * @name    Events related macros
+ * @{
+ */
+/**
+ * @brief   All events allowed mask.
+ */
+#define ALL_EVENTS              ((eventmask_t)-1)
+
+/**
+ * @brief   Returns an event mask from an event identifier.
+ */
+#define EVENT_MASK(eid)         ((eventmask_t)(1 << (eid)))
+/** @} */
+
+/*===========================================================================*/
+/* Module pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module data structures and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module macros.                                                            */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  void chEvtSignal(thread_t *tp, eventmask_t mask);
+  void chEvtSignalI(thread_t *tp, eventmask_t mask);
+  eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, sysinterval_t timeout);
+  eventmask_t chEvtWaitAllTimeout(eventmask_t mask, sysinterval_t timeout);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CH_CFG_USE_EVENTS == TRUE */
+
+#endif /* CHEVT_H */
+
+/** @} */
diff --git a/os/nil/include/chmsg.h b/os/nil/include/chmsg.h
new file mode 100644
index 000000000..b734645ca
--- /dev/null
+++ b/os/nil/include/chmsg.h
@@ -0,0 +1,103 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/include/chmsg.h
+ * @brief   Nil RTOS synchronous messages header file.
+ *
+ * @addtogroup NIL_MESSAGES
+ * @{
+ */
+
+#ifndef CHMSG_H
+#define CHMSG_H
+
+#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module constants.                                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module data structures and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module macros.                                                            */
+/*===========================================================================*/
+
+/**
+ * @name    Macro Functions
+ * @{
+ */
+/**
+ * @brief   Returns the message carried by the specified thread.
+ * @pre     This function must be invoked immediately after exiting a call
+ *          to @p chMsgWait().
+ *
+ * @param[in] tp        pointer to the thread
+ * @return              The message carried by the sender.
+ *
+ * @api
+ */
+#define chMsgGet(tp) ((tp)->sntmsg)
+
+/**
+ * @brief   Releases the thread waiting on top of the messages queue.
+ * @pre     Invoke this function only after a message has been received
+ *          using @p chMsgWait().
+ *
+ * @param[in] tp        pointer to the thread
+ * @param[in] msg       message to be returned to the sender
+ *
+ * @sclass
+ */
+#define chMsgReleaseS(tp, msg) do {                                         \
+  chSchReadyI(tp, msg);                                                     \
+  chSchRescheduleS();                                                       \
+  } while (0)
+/** @} */
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  msg_t chMsgSend(thread_t *tp, msg_t msg);
+  thread_t * chMsgWait(void);
+  void chMsgRelease(thread_t *tp, msg_t msg);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CH_CFG_USE_MESSAGES == TRUE */
+
+#endif /* CHMSG_H */
+
+/** @} */
diff --git a/os/nil/include/chsem.h b/os/nil/include/chsem.h
new file mode 100644
index 000000000..84da92684
--- /dev/null
+++ b/os/nil/include/chsem.h
@@ -0,0 +1,146 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/include/chsem.h
+ * @brief   Nil RTOS semaphores header file.
+ *
+ * @addtogroup NIL_SEMAPHORES
+ * @{
+ */
+
+#ifndef CHSEM_H
+#define CHSEM_H
+
+#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module constants.                                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module pre-compile time settings.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Derived constants and error checks.                                       */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module data structures and types.                                         */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module macros.                                                            */
+/*===========================================================================*/
+
+/**
+ * @name    Macro Functions
+ * @{
+ */
+/**
+ * @brief   Initializes a semaphore with the specified counter value.
+ *
+ * @param[out] sp       pointer to a @p semaphore_t structure
+ * @param[in] n         initial value of the semaphore counter. Must be
+ *                      non-negative.
+ *
+ * @init
+ */
+#define chSemObjectInit(sp, n) ((sp)->cnt = n)
+
+/**
+ * @brief   Performs a wait operation on a semaphore.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @return              A message specifying how the invoking thread has been
+ *                      released from the semaphore.
+ * @retval CH_MSG_OK   if the thread has not stopped on the semaphore or the
+ *                      semaphore has been signaled.
+ * @retval CH_MSG_RST  if the semaphore has been reset using @p chSemReset().
+ *
+ * @api
+ */
+#define chSemWait(sp) chSemWaitTimeout(sp, TIME_INFINITE)
+
+/**
+ * @brief   Performs a wait operation on a semaphore.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @return              A message specifying how the invoking thread has been
+ *                      released from the semaphore.
+ * @retval CH_MSG_OK   if the thread has not stopped on the semaphore or the
+ *                      semaphore has been signaled.
+ * @retval CH_MSG_RST  if the semaphore has been reset using @p chSemReset().
+ *
+ * @sclass
+ */
+#define chSemWaitS(sp) chSemWaitTimeoutS(sp, TIME_INFINITE)
+
+/**
+ * @brief   Decreases the semaphore counter.
+ * @details This macro can be used when the counter is known to be positive.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ *
+ * @iclass
+ */
+#define chSemFastWaitI(sp) ((sp)->cnt--)
+
+/**
+ * @brief   Increases the semaphore counter.
+ * @details This macro can be used when the counter is known to be not
+ *          negative.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ *
+ * @iclass
+ */
+#define chSemFastSignalI(sp) ((sp)->cnt++)
+
+/**
+ * @brief   Returns the semaphore counter current value.
+ *
+ * @iclass
+ */
+#define chSemGetCounterI(sp) ((sp)->cnt)
+/** @} */
+
+/*===========================================================================*/
+/* External declarations.                                                    */
+/*===========================================================================*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+  msg_t chSemWaitTimeout(semaphore_t *sp, sysinterval_t timeout);
+  msg_t chSemWaitTimeoutS(semaphore_t *sp, sysinterval_t timeout);
+  void chSemSignal(semaphore_t *sp);
+  void chSemSignalI(semaphore_t *sp);
+  void chSemReset(semaphore_t *sp, cnt_t n);
+  void chSemResetI(semaphore_t *sp, cnt_t n);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
+
+#endif /* CHSEM_H */
+
+/** @} */
diff --git a/os/nil/nil.mk b/os/nil/nil.mk
index 69238e91e..b4cc92b1a 100644
--- a/os/nil/nil.mk
+++ b/os/nil/nil.mk
@@ -14,8 +14,21 @@ endif
 CHCONF := $(strip $(shell cat $(CHCONFDIR)/chconf.h | egrep -e "\#define"))
 
 KERNSRC := ${CHIBIOS}/os/nil/src/ch.c
+ifneq ($(findstring CH_CFG_USE_EVENTS TRUE,$(CHCONF)),)
+KERNSRC += $(CHIBIOS)/os/rt/src/chevt.c
+endif
+ifneq ($(findstring CH_CFG_USE_MESSAGES TRUE,$(CHCONF)),)
+KERNSRC += $(CHIBIOS)/os/rt/src/chmsg.c
+endif
+ifneq ($(findstring CH_CFG_USE_SEMAPHORES TRUE,$(CHCONF)),)
+KERNSRC += $(CHIBIOS)/os/rt/src/chsem.c
+endif
+
 else
-KERNSRC := ${CHIBIOS}/os/nil/src/ch.c
+KERNSRC := ${CHIBIOS}/os/nil/src/ch.c \
+           ${CHIBIOS}/os/nil/src/chevt.c
+           ${CHIBIOS}/os/nil/src/chmsg.c \
+           ${CHIBIOS}/os/nil/src/chsem.c
 endif
 
 # Required include directories
diff --git a/os/nil/src/ch.c b/os/nil/src/ch.c
index 233a3f4ae..1d26e9565 100644
--- a/os/nil/src/ch.c
+++ b/os/nil/src/ch.c
@@ -48,27 +48,36 @@ nil_system_t nil;
 /* Module local functions.                                                   */
 /*===========================================================================*/
 
+/*===========================================================================*/
+/* Module interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions.                                                */
+/*===========================================================================*/
+
 /**
  * @brief   Retrieves the highest priority thread in the specified state and
  *          associated to the specified object.
- * @note    The search is unbounded, the thread is assumed to exist.
  *
  * @param[in] state     thread state
  * @param[in] p         object pointer
+ * @return              The pointer to the found thread.
+ * @retval NULL         if the thread is not found.
+ *
+ * @notapi
  */
-static thread_t *nil_find_thread(tstate_t state, void * p) {
+thread_t *nil_find_thread(tstate_t state, void *p) {
   thread_t *tp = nil.threads;
 
-  while (true) {
+  while (tp < &nil.threads[CH_CFG_MAX_THREADS]) {
     /* Is this thread matching?*/
     if ((tp->state == state) && (tp->u1.p == p)) {
       return tp;
     }
     tp++;
-
-    chDbgAssert(tp < &nil.threads[CH_CFG_MAX_THREADS],
-                "pointer out of range");
   }
+  return NULL;
 }
 
 /**
@@ -80,9 +89,9 @@ static thread_t *nil_find_thread(tstate_t state, void * p) {
  *                      non negative numbers are ignored
  * @param[in] msg       the wakeup message
  *
- * @iclass
+ * @notapi
  */
-static cnt_t nil_ready_all(void * p, cnt_t cnt, msg_t msg) {
+cnt_t nil_ready_all(void *p, cnt_t cnt, msg_t msg) {
   thread_t *tp = nil.threads;;
 
   while (cnt < (cnt_t)0) {
@@ -101,14 +110,6 @@ static cnt_t nil_ready_all(void * p, cnt_t cnt, msg_t msg) {
   return cnt;
 }
 
-/*===========================================================================*/
-/* Module interrupt handlers.                                                */
-/*===========================================================================*/
-
-/*===========================================================================*/
-/* Module exported functions.                                                */
-/*===========================================================================*/
-
 #if (CH_DBG_SYSTEM_STATE_CHECK == TRUE) || defined(__DOXYGEN__)
 /**
  * @brief   Guard code for @p chSysDisable().
@@ -1015,6 +1016,9 @@ void chThdDoDequeueNextI(threads_queue_t *tqp, msg_t msg) {
 
   tqp->cnt++;
   tp = nil_find_thread(NIL_STATE_WTQUEUE, (void *)tqp);
+
+  chDbgAssert(tp != NULL, "thread not found");
+
   (void) chSchReadyI(tp, msg);
 }
 
@@ -1053,290 +1057,4 @@ void chThdDequeueAllI(threads_queue_t *tqp, msg_t msg) {
   tqp->cnt = nil_ready_all((void *)tqp, tqp->cnt, msg);
 }
 
-#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
-/**
- * @brief   Performs a wait operation on a semaphore with timeout specification.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @param[in] timeout   the number of ticks before the operation timeouts,
- *                      the following special values are allowed:
- *                      - @a TIME_IMMEDIATE immediate timeout.
- *                      - @a TIME_INFINITE no timeout.
- *                      .
- * @return              A message specifying how the invoking thread has been
- *                      released from the semaphore.
- * @retval NIL_MSG_OK   if the thread has not stopped on the semaphore or the
- *                      semaphore has been signaled.
- * @retval NIL_MSG_RST  if the semaphore has been reset using @p chSemReset().
- * @retval NIL_MSG_TMO  if the semaphore has not been signaled or reset within
- *                      the specified timeout.
- *
- * @api
- */
-msg_t chSemWaitTimeout(semaphore_t *sp, sysinterval_t timeout) {
-  msg_t msg;
-
-  chSysLock();
-  msg = chSemWaitTimeoutS(sp, timeout);
-  chSysUnlock();
-
-  return msg;
-}
-
-/**
- * @brief   Performs a wait operation on a semaphore with timeout specification.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @param[in] timeout   the number of ticks before the operation timeouts,
- *                      the following special values are allowed:
- *                      - @a TIME_IMMEDIATE immediate timeout.
- *                      - @a TIME_INFINITE no timeout.
- *                      .
- * @return              A message specifying how the invoking thread has been
- *                      released from the semaphore.
- * @retval NIL_MSG_OK   if the thread has not stopped on the semaphore or the
- *                      semaphore has been signaled.
- * @retval NIL_MSG_RST  if the semaphore has been reset using @p chSemReset().
- * @retval NIL_MSG_TMO  if the semaphore has not been signaled or reset within
- *                      the specified timeout.
- *
- * @sclass
- */
-msg_t chSemWaitTimeoutS(semaphore_t *sp, sysinterval_t timeout) {
-
-  chDbgCheckClassS();
-  chDbgCheck(sp != NULL);
-
-  /* Note, the semaphore counter is a volatile variable so accesses are
-     manually optimized.*/
-  cnt_t cnt = sp->cnt;
-  if (cnt <= (cnt_t)0) {
-    if (TIME_IMMEDIATE == timeout) {
-
-      return MSG_TIMEOUT;
-    }
-    sp->cnt = cnt - (cnt_t)1;
-    nil.current->u1.semp = sp;
-
-    return chSchGoSleepTimeoutS(NIL_STATE_WTQUEUE, timeout);
-  }
-  sp->cnt = cnt - (cnt_t)1;
-
-  return MSG_OK;
-}
-
-/**
- * @brief   Performs a signal operation on a semaphore.
- *
- * @param[in] sp    pointer to a @p semaphore_t structure
- *
- * @api
- */
-void chSemSignal(semaphore_t *sp) {
-
-  chSysLock();
-  chSemSignalI(sp);
-  chSchRescheduleS();
-  chSysUnlock();
-}
-
-/**
- * @brief   Performs a signal operation on a semaphore.
- * @post    This function does not reschedule so a call to a rescheduling
- *          function must be performed before unlocking the kernel. Note that
- *          interrupt handlers always reschedule on exit so an explicit
- *          reschedule must not be performed in ISRs.
- *
- * @param[in] sp    pointer to a @p semaphore_t structure
- *
- * @iclass
- */
-void chSemSignalI(semaphore_t *sp) {
-
-  chDbgCheckClassI();
-  chDbgCheck(sp != NULL);
-
-  if (++sp->cnt <= (cnt_t)0) {
-    thread_t *tp = nil_find_thread(NIL_STATE_WTQUEUE, (void *)sp);
-    (void) chSchReadyI(tp, MSG_OK);
-  }
-}
-
-/**
- * @brief   Performs a reset operation on the semaphore.
- * @post    After invoking this function all the threads waiting on the
- *          semaphore, if any, are released and the semaphore counter is set
- *          to the specified, non negative, value.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @param[in] n         the new value of the semaphore counter. The value must
- *                      be non-negative.
- *
- * @api
- */
-void chSemReset(semaphore_t *sp, cnt_t n) {
-
-  chSysLock();
-  chSemResetI(sp, n);
-  chSchRescheduleS();
-  chSysUnlock();
-}
-
-/**
- * @brief   Performs a reset operation on the semaphore.
- * @post    After invoking this function all the threads waiting on the
- *          semaphore, if any, are released and the semaphore counter is set
- *          to the specified, non negative, value.
- * @post    This function does not reschedule so a call to a rescheduling
- *          function must be performed before unlocking the kernel. Note that
- *          interrupt handlers always reschedule on exit so an explicit
- *          reschedule must not be performed in ISRs.
- *
- * @param[in] sp        pointer to a @p semaphore_t structure
- * @param[in] n         the new value of the semaphore counter. The value must
- *                      be non-negative.
- *
- * @iclass
- */
-void chSemResetI(semaphore_t *sp, cnt_t n) {
-  cnt_t cnt;
-
-  chDbgCheckClassI();
-  chDbgCheck((sp != NULL) && (n >= (cnt_t)0));
-
-  cnt = sp->cnt;
-  sp->cnt = n;
-
-  /* Does nothing for cnt >= 0, calling anyway.*/
-  (void) nil_ready_all((void *)sp, cnt, MSG_RESET);
-}
-#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
-
-#if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
-/**
- * @brief   Adds a set of event flags directly to the specified @p thread_t.
- *
- * @param[in] tp        the thread to be signaled
- * @param[in] mask      the event flags set to be ORed
- *
- * @api
- */
-void chEvtSignal(thread_t *tp, eventmask_t mask) {
-
-  chSysLock();
-  chEvtSignalI(tp, mask);
-  chSchRescheduleS();
-  chSysUnlock();
-}
-
-/**
- * @brief   Adds a set of event flags directly to the specified @p thread_t.
- * @post    This function does not reschedule so a call to a rescheduling
- *          function must be performed before unlocking the kernel. Note that
- *          interrupt handlers always reschedule on exit so an explicit
- *          reschedule must not be performed in ISRs.
- *
- * @param[in] tp        the thread to be signaled
- * @param[in] mask      the event flags set to be ORed
- *
- * @iclass
- */
-void chEvtSignalI(thread_t *tp, eventmask_t mask) {
-
-  chDbgCheckClassI();
-  chDbgCheck(tp != NULL);
-
-  tp->epmask |= mask;
-  if ((NIL_THD_IS_WTOREVT(tp) &&
-       ((tp->epmask & tp->u1.ewmask) != (eventmask_t)0)) ||
-      (NIL_THD_IS_WTANDEVT(tp) &&
-       ((tp->epmask & tp->u1.ewmask) == tp->u1.ewmask))) {
-    (void) chSchReadyI(tp, MSG_OK);
-  }
-}
-
-/**
- * @brief   Waits for any of the specified events.
- * @details The function waits for any event among those specified in
- *          @p mask to become pending then the events are cleared and
- *          returned.
- *
- * @param[in] mask      mask of the event flags that the function should wait
- *                      for, @p ALL_EVENTS enables all the events
- * @param[in] timeout   the number of ticks before the operation timeouts,
- *                      the following special values are allowed:
- *                      - @a TIME_IMMEDIATE immediate timeout.
- *                      - @a TIME_INFINITE no timeout.
- *                      .
- * @return              The mask of the served and cleared events.
- * @retval 0            if the operation has timed out.
- *
- * @api
- */
-eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, sysinterval_t timeout) {
-  thread_t *ctp = nil.current;
-  eventmask_t m;
-
-  chSysLock();
-  if ((m = (ctp->epmask & mask)) == (eventmask_t)0) {
-    if (TIME_IMMEDIATE == timeout) {
-      chSysUnlock();
-
-      return (eventmask_t)0;
-    }
-    ctp->u1.ewmask = mask;
-    if (chSchGoSleepTimeoutS(NIL_STATE_WTOREVT, timeout) < MSG_OK) {
-      chSysUnlock();
-
-      return (eventmask_t)0;
-    }
-    m = ctp->epmask & mask;
-  }
-  ctp->epmask &= ~m;
-  chSysUnlock();
-
-  return m;
-}
-
-/**
- * @brief   Waits for all the specified events.
- * @details The function waits for all the events specified in @p mask to
- *          become pending then the events are cleared and returned.
- *
- * @param[in] mask      mask of the event flags that the function should wait
- *                      for, @p ALL_EVENTS enables all the events
- * @param[in] timeout   the number of ticks before the operation timeouts,
- *                      the following special values are allowed:
- *                      - @a TIME_IMMEDIATE immediate timeout.
- *                      - @a TIME_INFINITE no timeout.
- *                      .
- * @return              The mask of the served and cleared events.
- * @retval 0            if the operation has timed out.
- *
- * @api
- */
-eventmask_t chEvtWaitAllTimeout(eventmask_t mask, sysinterval_t timeout) {
-  thread_t *ctp = nil.current;
-
-  chSysLock();
-  if ((ctp->epmask & mask) != mask) {
-    if (TIME_IMMEDIATE == timeout) {
-      chSysUnlock();
-
-      return (eventmask_t)0;
-    }
-    ctp->u1.ewmask = mask;
-    if (chSchGoSleepTimeoutS(NIL_STATE_WTANDEVT, timeout) < MSG_OK) {
-      chSysUnlock();
-
-      return (eventmask_t)0;
-    }
-  }
-  ctp->epmask &= ~mask;
-  chSysUnlock();
-
-  return mask;
-}
-#endif /* CH_CFG_USE_EVENTS == TRUE */
-
 /** @} */
diff --git a/os/nil/src/chevt.c b/os/nil/src/chevt.c
new file mode 100644
index 000000000..16746177f
--- /dev/null
+++ b/os/nil/src/chevt.c
@@ -0,0 +1,183 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/src/chevt.c
+ * @brief   Nil RTOS events source file.
+ *
+ * @addtogroup NIL_EVENTS
+ * @{
+ */
+
+#include "ch.h"
+
+#if (CH_CFG_USE_EVENTS == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported variables.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local variables.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Adds a set of event flags directly to the specified @p thread_t.
+ *
+ * @param[in] tp        the thread to be signaled
+ * @param[in] mask      the event flags set to be ORed
+ *
+ * @api
+ */
+void chEvtSignal(thread_t *tp, eventmask_t mask) {
+
+  chSysLock();
+  chEvtSignalI(tp, mask);
+  chSchRescheduleS();
+  chSysUnlock();
+}
+
+/**
+ * @brief   Adds a set of event flags directly to the specified @p thread_t.
+ * @post    This function does not reschedule so a call to a rescheduling
+ *          function must be performed before unlocking the kernel. Note that
+ *          interrupt handlers always reschedule on exit so an explicit
+ *          reschedule must not be performed in ISRs.
+ *
+ * @param[in] tp        the thread to be signaled
+ * @param[in] mask      the event flags set to be ORed
+ *
+ * @iclass
+ */
+void chEvtSignalI(thread_t *tp, eventmask_t mask) {
+
+  chDbgCheckClassI();
+  chDbgCheck(tp != NULL);
+
+  tp->epmask |= mask;
+  if ((NIL_THD_IS_WTOREVT(tp) &&
+       ((tp->epmask & tp->u1.ewmask) != (eventmask_t)0)) ||
+      (NIL_THD_IS_WTANDEVT(tp) &&
+       ((tp->epmask & tp->u1.ewmask) == tp->u1.ewmask))) {
+    (void) chSchReadyI(tp, MSG_OK);
+  }
+}
+
+/**
+ * @brief   Waits for any of the specified events.
+ * @details The function waits for any event among those specified in
+ *          @p mask to become pending then the events are cleared and
+ *          returned.
+ *
+ * @param[in] mask      mask of the event flags that the function should wait
+ *                      for, @p ALL_EVENTS enables all the events
+ * @param[in] timeout   the number of ticks before the operation timeouts,
+ *                      the following special values are allowed:
+ *                      - @a TIME_IMMEDIATE immediate timeout.
+ *                      - @a TIME_INFINITE no timeout.
+ *                      .
+ * @return              The mask of the served and cleared events.
+ * @retval 0            if the operation has timed out.
+ *
+ * @api
+ */
+eventmask_t chEvtWaitAnyTimeout(eventmask_t mask, sysinterval_t timeout) {
+  thread_t *ctp = nil.current;
+  eventmask_t m;
+
+  chSysLock();
+  if ((m = (ctp->epmask & mask)) == (eventmask_t)0) {
+    if (TIME_IMMEDIATE == timeout) {
+      chSysUnlock();
+
+      return (eventmask_t)0;
+    }
+    ctp->u1.ewmask = mask;
+    if (chSchGoSleepTimeoutS(NIL_STATE_WTOREVT, timeout) < MSG_OK) {
+      chSysUnlock();
+
+      return (eventmask_t)0;
+    }
+    m = ctp->epmask & mask;
+  }
+  ctp->epmask &= ~m;
+  chSysUnlock();
+
+  return m;
+}
+
+/**
+ * @brief   Waits for all the specified events.
+ * @details The function waits for all the events specified in @p mask to
+ *          become pending then the events are cleared and returned.
+ *
+ * @param[in] mask      mask of the event flags that the function should wait
+ *                      for, @p ALL_EVENTS enables all the events
+ * @param[in] timeout   the number of ticks before the operation timeouts,
+ *                      the following special values are allowed:
+ *                      - @a TIME_IMMEDIATE immediate timeout.
+ *                      - @a TIME_INFINITE no timeout.
+ *                      .
+ * @return              The mask of the served and cleared events.
+ * @retval 0            if the operation has timed out.
+ *
+ * @api
+ */
+eventmask_t chEvtWaitAllTimeout(eventmask_t mask, sysinterval_t timeout) {
+  thread_t *ctp = nil.current;
+
+  chSysLock();
+  if ((ctp->epmask & mask) != mask) {
+    if (TIME_IMMEDIATE == timeout) {
+      chSysUnlock();
+
+      return (eventmask_t)0;
+    }
+    ctp->u1.ewmask = mask;
+    if (chSchGoSleepTimeoutS(NIL_STATE_WTANDEVT, timeout) < MSG_OK) {
+      chSysUnlock();
+
+      return (eventmask_t)0;
+    }
+  }
+  ctp->epmask &= ~mask;
+  chSysUnlock();
+
+  return mask;
+}
+
+#endif /* CH_CFG_USE_EVENTS == TRUE */
+
+/** @} */
diff --git a/os/nil/src/chmsg.c b/os/nil/src/chmsg.c
new file mode 100644
index 000000000..08a6a9a71
--- /dev/null
+++ b/os/nil/src/chmsg.c
@@ -0,0 +1,133 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/src/chmsg.c
+ * @brief   Nil RTOS synchronous messages source file.
+ *
+ * @addtogroup NIL_MESSAGES
+ * @{
+ */
+
+#include "ch.h"
+
+#if (CH_CFG_USE_MESSAGES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported variables.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local variables.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Sends a message to the specified thread.
+ * @details The sender is stopped until the receiver executes a
+ *          @p chMsgRelease()after receiving the message.
+ *
+ * @param[in] tp        the pointer to the thread
+ * @param[in] msg       the message
+ * @return              The answer message from @p chMsgRelease().
+ *
+ * @api
+ */
+msg_t chMsgSend(thread_t *tp, msg_t msg) {
+  thread_t *ctp = nil.current;
+
+  chDbgCheck(tp != NULL);
+
+  chSysLock();
+  ctp->sntmsg = msg;
+  ctp->u1.tp =  tp;
+  if (NIL_THD_IS_WTMSG(tp)) {
+    (void) chSchReadyI(tp, (msg_t)ctp);
+  }
+  msg = chSchGoSleepTimeoutS(NIL_STATE_SNDMSGQ, TIME_INFINITE);
+  chSysUnlock();
+
+  return msg;
+}
+
+/**
+ * @brief   Suspends the thread and waits for an incoming message.
+ * @post    After receiving a message the function @p chMsgGet() must be
+ *          called in order to retrieve the message and then @p chMsgRelease()
+ *          must be invoked in order to acknowledge the reception and send
+ *          the answer.
+ * @note    If the message is a pointer then you can assume that the data
+ *          pointed by the message is stable until you invoke @p chMsgRelease()
+ *          because the sending thread is suspended until then.
+ * @note    The reference counter of the sender thread is not increased, the
+ *          returned pointer is a temporary reference.
+ *
+ * @return              A pointer to the thread carrying the message.
+ *
+ * @api
+ */
+thread_t *chMsgWait(void) {
+  thread_t *tp;
+
+  chSysLock();
+  tp = nil_find_thread(NIL_STATE_SNDMSGQ, nil.current);
+  if (tp == NULL) {
+    tp = (thread_t *)chSchGoSleepTimeoutS(NIL_STATE_WTMSG, TIME_INFINITE);
+  }
+  chSysUnlock();
+
+  return tp;
+}
+
+/**
+ * @brief   Releases a sender thread specifying a response message.
+ * @pre     Invoke this function only after a message has been received
+ *          using @p chMsgWait().
+ *
+ * @param[in] tp        pointer to the thread
+ * @param[in] msg       message to be returned to the sender
+ *
+ * @api
+ */
+void chMsgRelease(thread_t *tp, msg_t msg) {
+
+  chSysLock();
+  chDbgAssert(tp->state == NIL_STATE_SNDMSGQ, "invalid state");
+  chMsgReleaseS(tp, msg);
+  chSysUnlock();
+}
+
+#endif /* CH_CFG_USE_MESSAGES == TRUE */
+
+/** @} */
diff --git a/os/nil/src/chsem.c b/os/nil/src/chsem.c
new file mode 100644
index 000000000..d56bf03c0
--- /dev/null
+++ b/os/nil/src/chsem.c
@@ -0,0 +1,218 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio.
+
+    This file is part of ChibiOS.
+
+    ChibiOS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    ChibiOS is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file    nil/src/chsem.c
+ * @brief   Nil RTOS semaphores source file.
+ *
+ * @addtogroup NIL_SEMAPHORES
+ * @{
+ */
+
+#include "ch.h"
+
+#if (CH_CFG_USE_SEMAPHORES == TRUE) || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Module local definitions.                                                 */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported variables.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local variables.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module local functions.                                                   */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module interrupt handlers.                                                */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Module exported functions.                                                */
+/*===========================================================================*/
+
+/**
+ * @brief   Performs a wait operation on a semaphore with timeout specification.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @param[in] timeout   the number of ticks before the operation timeouts,
+ *                      the following special values are allowed:
+ *                      - @a TIME_IMMEDIATE immediate timeout.
+ *                      - @a TIME_INFINITE no timeout.
+ *                      .
+ * @return              A message specifying how the invoking thread has been
+ *                      released from the semaphore.
+ * @retval NIL_MSG_OK   if the thread has not stopped on the semaphore or the
+ *                      semaphore has been signaled.
+ * @retval NIL_MSG_RST  if the semaphore has been reset using @p chSemReset().
+ * @retval NIL_MSG_TMO  if the semaphore has not been signaled or reset within
+ *                      the specified timeout.
+ *
+ * @api
+ */
+msg_t chSemWaitTimeout(semaphore_t *sp, sysinterval_t timeout) {
+  msg_t msg;
+
+  chSysLock();
+  msg = chSemWaitTimeoutS(sp, timeout);
+  chSysUnlock();
+
+  return msg;
+}
+
+/**
+ * @brief   Performs a wait operation on a semaphore with timeout specification.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @param[in] timeout   the number of ticks before the operation timeouts,
+ *                      the following special values are allowed:
+ *                      - @a TIME_IMMEDIATE immediate timeout.
+ *                      - @a TIME_INFINITE no timeout.
+ *                      .
+ * @return              A message specifying how the invoking thread has been
+ *                      released from the semaphore.
+ * @retval NIL_MSG_OK   if the thread has not stopped on the semaphore or the
+ *                      semaphore has been signaled.
+ * @retval NIL_MSG_RST  if the semaphore has been reset using @p chSemReset().
+ * @retval NIL_MSG_TMO  if the semaphore has not been signaled or reset within
+ *                      the specified timeout.
+ *
+ * @sclass
+ */
+msg_t chSemWaitTimeoutS(semaphore_t *sp, sysinterval_t timeout) {
+
+  chDbgCheckClassS();
+  chDbgCheck(sp != NULL);
+
+  /* Note, the semaphore counter is a volatile variable so accesses are
+     manually optimized.*/
+  cnt_t cnt = sp->cnt;
+  if (cnt <= (cnt_t)0) {
+    if (TIME_IMMEDIATE == timeout) {
+
+      return MSG_TIMEOUT;
+    }
+    sp->cnt = cnt - (cnt_t)1;
+    nil.current->u1.semp = sp;
+
+    return chSchGoSleepTimeoutS(NIL_STATE_WTQUEUE, timeout);
+  }
+  sp->cnt = cnt - (cnt_t)1;
+
+  return MSG_OK;
+}
+
+/**
+ * @brief   Performs a signal operation on a semaphore.
+ *
+ * @param[in] sp    pointer to a @p semaphore_t structure
+ *
+ * @api
+ */
+void chSemSignal(semaphore_t *sp) {
+
+  chSysLock();
+  chSemSignalI(sp);
+  chSchRescheduleS();
+  chSysUnlock();
+}
+
+/**
+ * @brief   Performs a signal operation on a semaphore.
+ * @post    This function does not reschedule so a call to a rescheduling
+ *          function must be performed before unlocking the kernel. Note that
+ *          interrupt handlers always reschedule on exit so an explicit
+ *          reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp    pointer to a @p semaphore_t structure
+ *
+ * @iclass
+ */
+void chSemSignalI(semaphore_t *sp) {
+
+  chDbgCheckClassI();
+  chDbgCheck(sp != NULL);
+
+  if (++sp->cnt <= (cnt_t)0) {
+    thread_t *tp = nil_find_thread(NIL_STATE_WTQUEUE, (void *)sp);
+
+    chDbgAssert(tp != NULL, "thread not found");
+
+    (void) chSchReadyI(tp, MSG_OK);
+  }
+}
+
+/**
+ * @brief   Performs a reset operation on the semaphore.
+ * @post    After invoking this function all the threads waiting on the
+ *          semaphore, if any, are released and the semaphore counter is set
+ *          to the specified, non negative, value.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @param[in] n         the new value of the semaphore counter. The value must
+ *                      be non-negative.
+ *
+ * @api
+ */
+void chSemReset(semaphore_t *sp, cnt_t n) {
+
+  chSysLock();
+  chSemResetI(sp, n);
+  chSchRescheduleS();
+  chSysUnlock();
+}
+
+/**
+ * @brief   Performs a reset operation on the semaphore.
+ * @post    After invoking this function all the threads waiting on the
+ *          semaphore, if any, are released and the semaphore counter is set
+ *          to the specified, non negative, value.
+ * @post    This function does not reschedule so a call to a rescheduling
+ *          function must be performed before unlocking the kernel. Note that
+ *          interrupt handlers always reschedule on exit so an explicit
+ *          reschedule must not be performed in ISRs.
+ *
+ * @param[in] sp        pointer to a @p semaphore_t structure
+ * @param[in] n         the new value of the semaphore counter. The value must
+ *                      be non-negative.
+ *
+ * @iclass
+ */
+void chSemResetI(semaphore_t *sp, cnt_t n) {
+  cnt_t cnt;
+
+  chDbgCheckClassI();
+  chDbgCheck((sp != NULL) && (n >= (cnt_t)0));
+
+  cnt = sp->cnt;
+  sp->cnt = n;
+
+  /* Does nothing for cnt >= 0, calling anyway.*/
+  (void) nil_ready_all((void *)sp, cnt, MSG_RESET);
+}
+
+#endif /* CH_CFG_USE_SEMAPHORES == TRUE */
+
+/** @} */
diff --git a/test/lib/ch_test.c b/test/lib/ch_test.c
index 859ecdf9f..f7eb8f453 100644
--- a/test/lib/ch_test.c
+++ b/test/lib/ch_test.c
@@ -255,6 +255,23 @@ msg_t test_execute(BaseSequentialStream *stream, const testsuite_t *tsp) {
   test_print("*** Test Board:   ");
   test_println(BOARD_NAME);
 #endif
+#if defined(__GNUC__) && !defined(TEST_SUPPRESS_SIZE_REPORT)
+  {
+    extern uint8_t __text_base, __text_end,
+                   _data_start, _data_end,
+                   _bss_start, _bss_end;
+    test_println("***");
+    test_print("*** Text size:    ");
+    test_printn((uint32_t)(&__text_end - &__text_base));
+    test_println(" bytes");
+    test_print("*** Data size:    ");
+    test_printn((uint32_t)(&_data_end - &_data_start));
+    test_println(" bytes");
+    test_print("*** BSS size:     ");
+    test_printn((uint32_t)(&_bss_end - &_bss_start));
+    test_println(" bytes");
+  }
+#endif
 #if defined(TEST_REPORT_HOOK_HEADER)
   TEST_REPORT_HOOK_HEADER
 #endif