git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@95 35acf78f-673a-0410-8e92-d51de3d6d3f4

demos/ARM7-LPC214x-GCC/chcore.c

@@ -140,14 +140,15 @@ void hwinit(void) {
   InitBuzzer();
 }
 
-void chSysPause(void) {
+/*
-
+ * System idle thread loop.
-  chThdSetPriority(IDLEPRIO);
+ */
+void _IdleThread(void *p) {
 
   while (TRUE) {
 // Note, it is disabled because it causes trouble with the JTAG probe.
 // Enable it in the final code only.
-//    PCON = 1;   /* Stops CPU clock until next interrupt. */
+//    PCON = 1;
   }
 }
 

demos/ARM7-LPC214x-GCC/chcore.h

@@ -98,6 +98,10 @@ extern void chSysUnlock(void);
 #define UserStackSize(n) (sizeof(Thread) + \
                           sizeof(struct stackregs) + (n) + (INT_REQUIRED_STACK))
 
+
+#define IDLE_THREAD_STACK_SIZE 8
+void _IdleThread(void *p) __attribute__((noreturn));
+
 void chSysHalt(void) __attribute__((noreturn));
 void chSysPause(void)  __attribute__((noreturn));
 void chSysSwitchI(Context *oldp, Context *newp);

demos/ARM7-LPC214x-GCC/main.c

@@ -25,18 +25,6 @@
 #include "buzzer.h"
 #include "evtimer.h"
 
-/*
- * System Idle Thread, this thread only runs when on other threads in the
- * system require the CPU.
- * The role of this thread is to minimize the power consumption when idling
- * and serve the interrupts.
- */
-static BYTE8 waIdleThread[UserStackSize(16)];
-static t_msg IdleThread(void *arg) {
-
-  chSysPause();
-}
-
 /*
  * Red LEDs blinker thread, times are in milliseconds.
  */
@@ -138,15 +126,6 @@ int main(int argc, char **argv) {
    */
   chSysInit();
 
-  /*
-   * 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), IdleThread, NULL);
-
   /*
    * If a button is pressed during the reset then the blinking leds threads
    * are not started in order to make accurate benchmarks.
@@ -163,7 +142,7 @@ int main(int argc, char **argv) {
   chThdSetPriority(NORMALPRIO);
 
   /*
-   * Normal main() activity, in this demo it server events incoming from
+   * Normal main() activity, in this demo it serves events generated by
    * various sources.
    */
   evtInit(&evt, 500);           /* Initializes an event timer object.   */

readme.txt

@@ -39,6 +39,13 @@ AVR-AT90CANx-GCC    - Port on AVR AT90CAN128, not complete yet.
 *****************************************************************************
 
 *** 0.4.1 ***
+- Modified the initialization code in order to have a dedicated idle thread in
+  the system, now the main() function behaves like a normal thread after
+  executing chSysInit() and can use all the ChibiOS/RT APIs (it was required
+  to run the idle loop in previous versions).
+  Now it is also possible to use ChibiOS/RT with a single main() thread and
+  just use it for the I/O capabilities, Virtual Timers and events. You don't
+  have to use multiple threads if you don't really need to.
 - Cleaned up the LPC2148 demo in main.c, it is now well documented and
   explains everything, I assumed too much stuff to be "obvious".
 - Added a spreadsheet in the documentation that describes the advantages
@@ -51,7 +58,7 @@ AVR-AT90CANx-GCC    - Port on AVR AT90CAN128, not complete yet.
   is bad for a RTOS. This option however increases the code size slightly
   because of the alignment gaps.
 - Fine tuning in the scheduler code for improved performance, deeper
-  inlining and small changes.
+  inlining and small changes, about 5% better scheduler performance.
 - Increased the default system-mode stack size from 128 to 256 bytes because
   some optimizations and the THUMB mode seem to use more stack space.
 - Included a Makefile in the LPC2148 demo that builds in THUMB mode.

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
+ * instructions stream becomes the main thread.
- * 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
  * @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
+ * @note The main thread is created with priority \p NORMALPRIO.
- *       \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().
  */
 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);
+  _InitThread(NORMALPRIO, 0, &mainthread);
-  idlethread.p_state = PRCURR;
+  mainthread.p_state = PRCURR;
-  currp = &idlethread;
+  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);
 }
 
 /** @} */

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) {
+void _IdleThread(void *p) {
-
-  chThdSetPriority(IDLEPRIO);
 
   while (TRUE)
     ;

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_ */