From 4fc627f08b942df8312ad02f24a361b18c4b790b Mon Sep 17 00:00:00 2001
From: gdisirio <gdisirio@35acf78f-673a-0410-8e92-d51de3d6d3f4>
Date: Sun, 18 Nov 2007 09:45:45 +0000
Subject: git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@95
 35acf78f-673a-0410-8e92-d51de3d6d3f4

---
 src/chinit.c           | 36 ++++++++++++++++++------------------
 src/templates/chcore.c |  4 +---
 src/templates/chcore.h | 16 ++++++++++++++--
 3 files changed, 33 insertions(+), 23 deletions(-)

(limited to 'src')

diff --git a/src/chinit.c b/src/chinit.c
index 4a25567a8..918da1796 100644
--- a/src/chinit.c
+++ b/src/chinit.c
@@ -24,27 +24,17 @@
 
 #include <ch.h>
 
-static Thread idlethread;
 
 /**
  * ChibiOS/RT initialization. After executing this function the current
- * instructions stream becomes the idle thread. The thread must execute the
- * first user thread and then go to sleep into the \p chSysPause() where it
- * will just serve the interrupts while keeping the lowest possible power
- * mode.<br><br>
- * @code
- *   chSysInit();
- *   chThdCreate(...); // Starts one or more user threads.
- *   chSysPause();
- * @endcode
+ * instructions stream becomes the main thread.
  * @note Interrupts should be still disabled when \p chSysInit() is invoked
  *       and are internally enabled.
- * @note The idle thread has absolute priority when exiting from the
- *       \p chSysInit(), this is done to make sure that all the initializations
- *       performed in the \p main() procedure are completed before any thread
- *       starts. The priority is set to \p IDLEPRIO into the \p chSysPause().
+ * @note The main thread is created with priority \p NORMALPRIO.
  */
 void chSysInit(void) {
+  static Thread mainthread;
+  static BYTE8 waIdleThread[UserStackSize(IDLE_THREAD_STACK_SIZE)];
 
   chSchInit();
   chDbgInit();
@@ -52,13 +42,23 @@ void chSysInit(void) {
   chVTInit();
 #endif
   /*
-   * Now this instructions flow becomes the idle thread.
+   * Now this instructions flow becomes the main thread.
    */
-  _InitThread(ABSPRIO, 0, &idlethread);
-  idlethread.p_state = PRCURR;
-  currp = &idlethread;
+  _InitThread(NORMALPRIO, 0, &mainthread);
+  mainthread.p_state = PRCURR;
+  currp = &mainthread;
 
   chSysUnlock();
+
+  /*
+   * The idle thread is created using the port-provided implementation.
+   * This thread has the lowest priority in the system, its role is just to
+   * execute the chSysPause() and serve interrupts in its context.
+   * In ChibiOS/RT at least one thread in the system *must* execute
+   * chThdPause(), it can be done in a dedicated thread or in the main()
+   * function (that would never exit the call).
+   */
+  chThdCreate(IDLEPRIO, 0, waIdleThread, sizeof(waIdleThread), (t_tfunc)_IdleThread, NULL);
 }
 
 /** @} */
diff --git a/src/templates/chcore.c b/src/templates/chcore.c
index bc8c68b90..ec2b39592 100644
--- a/src/templates/chcore.c
+++ b/src/templates/chcore.c
@@ -36,9 +36,7 @@
  * The priority is internally set to the minimum system value so that this
  * thread is executed only if there are no other ready threads in the system.
  */
-void chSysPause(void) {
-
-  chThdSetPriority(IDLEPRIO);
+void _IdleThread(void *p) {
 
   while (TRUE)
     ;
diff --git a/src/templates/chcore.h b/src/templates/chcore.h
index e917ffa6f..7f2c5fb0b 100644
--- a/src/templates/chcore.h
+++ b/src/templates/chcore.h
@@ -42,8 +42,20 @@ typedef struct {
 {                                                                  \
 }
 
-#define INT_REQUIRED_STACK 0  // Must include registers and stack frames.
+/**
+ * Stack size for the system idle thread.
+ */
+#define IDLE_THREAD_STACK_SIZE 0
 
+/**
+ * Per-thread stack overhead for interrupts servicing.
+ */
+#define INT_REQUIRED_STACK 0
+
+/**
+ * Macro to be used when allocating stack spaces, it adds the system-specific
+ * overhead.
+ */
 #define UserStackSize(n) (sizeof(Thread) + \
                           sizeof(struct stackregs) + (n) + (INT_REQUIRED_STACK))
 
@@ -74,8 +86,8 @@ typedef struct {
  */
 #define chSysPuts(msg) {}
 
+void _IdleThread(void *p);
 void chSysHalt(void);
-void chSysPause(void);
 void chSysSwitchI(Context *oldp, Context *newp);
 
 #endif /* _CHCORE_H_ */
-- 
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