Rationalize and document SCHEDULER_IDLE.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@66 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/cpu.h b/cpu.h
index 51314219e99350c340092c00f3205c7dba4cb428..8d9ed1db923d00955f9aa9fc57bc1cfd26d2d57c 100755 (executable)
--- a/cpu.h
+++ b/cpu.h
@@ -17,6 +17,9 @@
 
 /*
  * $Log$
+ * Revision 1.6  2004/07/20 23:12:16  bernie
+ * Rationalize and document SCHEDULER_IDLE.
+ *
  * Revision 1.5  2004/07/20 16:20:35  bernie
  * Move byte-order macros to mware/byteorder.h; Add missing author names.
  *
@@ -51,7 +54,6 @@
        #define DISABLE_INTS            disable_interrupt()
        #define ENABLE_INTS             enable_interrupt()
        #define NOP                     nop_instruction()
-       #define SCHEDULER_IDLE          /* Hmmm... could we go in STOP mode? */
 
        typedef uint16_t cpuflags_t; // FIXME
        typedef unsigned int cpustack_t;
@@ -66,7 +68,6 @@
        #define NOP                     asm volatile ("nop")
        #define DISABLE_INTS            /* nothing */
        #define ENABLE_INTS             /* nothing */
-       #define SCHEDULER_IDLE          SchedulerIdle()
 
        typedef uint32_t cpuflags_t; // FIXME
        typedef uint32_t cpustack_t;
@@ -81,7 +82,6 @@
        #define NOP                     asm(nop)
        #define DISABLE_INTS            do { asm(bfset #0x0200,SR); asm(nop); } while (0)
        #define ENABLE_INTS             do { asm(bfclr #0x0200,SR); asm(nop); } while (0)
-       #define SCHEDULER_IDLE          /* nothing */
 
        #define DISABLE_IRQSAVE(x)  \
                do { asm(move SR,x); asm(bfset #0x0200,SR); } while (0)
@@ -116,7 +116,6 @@
        #define NOP                     asm volatile ("nop" ::)
        #define DISABLE_INTS            asm volatile ("cli" ::)
        #define ENABLE_INTS             asm volatile ("sei" ::)
-       #define SCHEDULER_IDLE          /* nothing */
 
        #define DISABLE_IRQSAVE(x) \
        do { \
@@ -218,4 +217,25 @@
                CPU_PUSH_WORD((sp), (func))
 #endif
 
+
+/*!
+ * \name SCHEDULER_IDLE
+ *
+ * \brief Invoked by the scheduler to stop the CPU when idle.
+ *
+ * This hook can be redefined to put the CPU in low-power mode, or to
+ * profile system load with an external strobe, or to save CPU cycles
+ * in hosted environments such as emulators.
+ */
+#ifndef SCHEDULER_IDLE
+       #if (ARCH & ARCH_EMUL)
+               /* This emulator hook should yeld the CPU to the host.  */
+               EXTERN_C_BEGIN
+               void SchedulerIdle(void);
+               EXTERN_C_END
+       #else /* !ARCH_EMUL */
+               #define SCHEDULER_IDLE /* nothing */
+       #endif /* !ARCH_EMUL */
+#endif /* !SCHEDULER_IDLE */
+
 #endif /* CPU_H */