Document AVR dependency.

[bertos.git] / cpu.h

diff --git a/cpu.h b/cpu.h
index 335876130765ffd001011786086c1da0aef8101b..4715908b3d5666804b1a7209fb8f2f7a1ffdb41e 100755 (executable)
--- a/cpu.h
+++ b/cpu.h
@@ -11,10 +11,24 @@
  * \version $Id$
  *
  * \author Giovanni Bajo <rasky@develer.com>
+ * \author Bernardo Innocenti <bernie@develer.com>
+ * \author Stefano Fedrigo <aleph@develer.com>
  */
 
 /*
  * $Log$
+ * Revision 1.7  2004/07/20 23:26:48  bernie
+ * Fix two errors introduced by previous commit.
+ *
+ * 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.
+ *
+ * Revision 1.4  2004/07/20 16:06:04  bernie
+ * Add macros to handle endianess issues.
+ *
  * Revision 1.3  2004/07/18 21:49:51  bernie
  * Fixes for GCC 3.5.
  *
@@ -33,12 +47,16 @@
 //! Initialization value for registers in stack frame
 #define CPU_REG_INIT_VALUE(reg)     0
 
+// Macros for determining CPU endianness
+#define CPU_BIG_ENDIAN    0x1234
+#define CPU_LITTLE_ENDIAN 0x3412
+
+
 #if defined(__IAR_SYSTEMS_ICC) || defined(__IAR_SYSTEMS_ICC__)  /* 80C196 */
 
        #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;
@@ -46,13 +64,13 @@
        #define CPU_REGS_CNT            16
        #define CPU_STACK_GROWS_UPWARD  0
        #define CPU_SP_ON_EMPTY_SLOT    0
+       #define CPU_BYTE_ORDER          CPU_LITTLE_ENDIAN
 
 #elif defined(__i386__) || defined(_MSC_VER) /* x86 */
 
        #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;
@@ -60,13 +78,13 @@
        #define CPU_REGS_CNT            7
        #define CPU_STACK_GROWS_UPWARD  0
        #define CPU_SP_ON_EMPTY_SLOT    0
+       #define CPU_BYTE_ORDER          CPU_LITTLE_ENDIAN
 
 #elif defined(__m56800E__) || defined(__m56800__) /* DSP56K */
 
        #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)
@@ -80,6 +98,7 @@
        #define CPU_SAVED_REGS_CNT      28
        #define CPU_STACK_GROWS_UPWARD  1
        #define CPU_SP_ON_EMPTY_SLOT    0
+       #define CPU_BYTE_ORDER          CPU_BIG_ENDIAN
 
        #undef CPU_REG_INIT_VALUE
        INLINE uint16_t CPU_REG_INIT_VALUE(int reg)
@@ -100,7 +119,6 @@
        #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 { \
@@ -125,7 +143,7 @@
        #define CPU_SAVED_REGS_CNT      18
        #define CPU_STACK_GROWS_UPWARD  0
        #define CPU_SP_ON_EMPTY_SLOT    1
-
+       #define CPU_BYTE_ORDER          CPU_LITTLE_ENDIAN
 #else
        #error Unknown CPU
 #endif
@@ -202,4 +220,25 @@
                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 defined(ARCH_EMUL) && (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 */