Merged PowerPC port as submitted by Andy Bray of I-CUBED, Ltd

(andy@i-cubed.demon.co.uk).  This initial submission is known
to work on the IBM 403.  It is thought to work on the Motorola
601, 603, and 604 although this remains to be tested.

Another user -- Doug Currie (e@flavors.com) -- is interested in
this work and will be testing it on the 604 using the Metrowerks
C compiler and a different format assembly language.

1 files changed, 1013 insertions, 0 deletions

diff --git a/c/src/exec/score/cpu/powerpc/cpu.h b/c/src/exec/score/cpu/powerpc/cpu.h
new file mode 100644
index 0000000000..82cad518e8
--- /dev/null
+++ b/c/src/exec/score/cpu/powerpc/cpu.h
@@ -0,0 +1,1013 @@
+/*  cpu.h
+ *
+ *  This include file contains information pertaining to the PowerPC
+ *  processor.
+ *
+ *  Author:	Andrew Bray <andy@i-cubed.demon.co.uk>
+ *
+ *  COPYRIGHT (c) 1995 by i-cubed ltd.
+ *
+ *  To anyone who acknowledges that this file is provided "AS IS"
+ *  without any express or implied warranty:
+ *      permission to use, copy, modify, and distribute this file
+ *      for any purpose is hereby granted without fee, provided that
+ *      the above copyright notice and this notice appears in all
+ *      copies, and that the name of i-cubed limited not be used in
+ *      advertising or publicity pertaining to distribution of the
+ *      software without specific, written prior permission.
+ *      i-cubed limited makes no representations about the suitability
+ *      of this software for any purpose.
+ *
+ *  Derived from c/src/exec/cpu/no_cpu/cpu.h:
+ *
+ *  COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
+ *  On-Line Applications Research Corporation (OAR).
+ *  All rights assigned to U.S. Government, 1994.
+ *
+ *  This material may be reproduced by or for the U.S. Government pursuant
+ *  to the copyright license under the clause at DFARS 252.227-7013.  This
+ *  notice must appear in all copies of this file and its derivatives.
+ *
+ */
+
+#ifndef __CPU_h
+#define __CPU_h
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rtems/ppc.h>               /* pick up machine definitions */
+#ifndef ASM
+struct CPU_Interrupt_frame;
+
+#include <rtems/ppctypes.h>
+#endif
+
+/* conditional compilation parameters */
+
+/*
+ *  Should the calls to _Thread_Enable_dispatch be inlined?
+ *
+ *  If TRUE, then they are inlined.
+ *  If FALSE, then a subroutine call is made.
+ *
+ *  Basically this is an example of the classic trade-off of size
+ *  versus speed.  Inlining the call (TRUE) typically increases the
+ *  size of RTEMS while speeding up the enabling of dispatching.
+ *  [NOTE: In general, the _Thread_Dispatch_disable_level will
+ *  only be 0 or 1 unless you are in an interrupt handler and that
+ *  interrupt handler invokes the executive.]  When not inlined
+ *  something calls _Thread_Enable_dispatch which in turns calls
+ *  _Thread_Dispatch.  If the enable dispatch is inlined, then
+ *  one subroutine call is avoided entirely.]
+ */
+
+#define CPU_INLINE_ENABLE_DISPATCH       FALSE
+
+/*
+ *  Should the body of the search loops in _Thread_queue_Enqueue_priority
+ *  be unrolled one time?  In unrolled each iteration of the loop examines
+ *  two "nodes" on the chain being searched.  Otherwise, only one node
+ *  is examined per iteration.
+ *
+ *  If TRUE, then the loops are unrolled.
+ *  If FALSE, then the loops are not unrolled.
+ *
+ *  The primary factor in making this decision is the cost of disabling
+ *  and enabling interrupts (_ISR_Flash) versus the cost of rest of the
+ *  body of the loop.  On some CPUs, the flash is more expensive than
+ *  one iteration of the loop body.  In this case, it might be desirable
+ *  to unroll the loop.  It is important to note that on some CPUs, this
+ *  code is the longest interrupt disable period in RTEMS.  So it is
+ *  necessary to strike a balance when setting this parameter.
+ */
+
+#define CPU_UNROLL_ENQUEUE_PRIORITY      FALSE
+
+/*
+ *  Does RTEMS manage a dedicated interrupt stack in software?
+ *
+ *  If TRUE, then a stack is allocated in _Interrupt_Manager_initialization.
+ *  If FALSE, nothing is done.
+ *
+ *  If the CPU supports a dedicated interrupt stack in hardware,
+ *  then it is generally the responsibility of the BSP to allocate it
+ *  and set it up.
+ *
+ *  If the CPU does not support a dedicated interrupt stack, then
+ *  the porter has two options: (1) execute interrupts on the
+ *  stack of the interrupted task, and (2) have RTEMS manage a dedicated
+ *  interrupt stack.
+ *
+ *  If this is TRUE, CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE.
+ *
+ *  Only one of CPU_HAS_SOFTWARE_INTERRUPT_STACK and
+ *  CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE.  It is
+ *  possible that both are FALSE for a particular CPU.  Although it
+ *  is unclear what that would imply about the interrupt processing
+ *  procedure on that CPU.
+ */
+
+#define CPU_HAS_SOFTWARE_INTERRUPT_STACK FALSE
+
+/*
+ *  Does this CPU have hardware support for a dedicated interrupt stack?
+ *
+ *  If TRUE, then it must be installed during initialization.
+ *  If FALSE, then no installation is performed.
+ *
+ *  If this is TRUE, CPU_ALLOCATE_INTERRUPT_STACK should also be TRUE.
+ *
+ *  Only one of CPU_HAS_SOFTWARE_INTERRUPT_STACK and
+ *  CPU_HAS_HARDWARE_INTERRUPT_STACK should be set to TRUE.  It is
+ *  possible that both are FALSE for a particular CPU.  Although it
+ *  is unclear what that would imply about the interrupt processing
+ *  procedure on that CPU.
+ */
+
+/*
+ *  ACB: This is a lie, but it gets us a handle on a call to set up
+ *  a variable derived from the top of the interrupt stack.
+ */
+
+#define CPU_HAS_HARDWARE_INTERRUPT_STACK TRUE
+
+/*
+ *  Does RTEMS allocate a dedicated interrupt stack in the Interrupt Manager?
+ *
+ *  If TRUE, then the memory is allocated during initialization.
+ *  If FALSE, then the memory is allocated during initialization.
+ *
+ *  This should be TRUE is CPU_HAS_SOFTWARE_INTERRUPT_STACK is TRUE
+ *  or CPU_INSTALL_HARDWARE_INTERRUPT_STACK is TRUE.
+ */
+
+#define CPU_ALLOCATE_INTERRUPT_STACK TRUE
+
+/*
+ *  Does the CPU have hardware floating point?
+ *
+ *  If TRUE, then the RTEMS_FLOATING_POINT task attribute is supported.
+ *  If FALSE, then the RTEMS_FLOATING_POINT task attribute is ignored.
+ *
+ *  If there is a FP coprocessor such as the i387 or mc68881, then
+ *  the answer is TRUE.
+ *
+ *  The macro name "PPC_HAS_FPU" should be made CPU specific.
+ *  It indicates whether or not this CPU model has FP support.  For
+ *  example, it would be possible to have an i386_nofp CPU model
+ *  which set this to false to indicate that you have an i386 without
+ *  an i387 and wish to leave floating point support out of RTEMS.
+ */
+
+#if ( PPC_HAS_FPU == 1 )
+#define CPU_HARDWARE_FP     TRUE
+#else
+#define CPU_HARDWARE_FP     FALSE
+#endif
+
+/*
+ *  Are all tasks RTEMS_FLOATING_POINT tasks implicitly?
+ *
+ *  If TRUE, then the RTEMS_FLOATING_POINT task attribute is assumed.
+ *  If FALSE, then the RTEMS_FLOATING_POINT task attribute is followed.
+ *
+ *  So far, the only CPU in which this option has been used is the
+ *  HP PA-RISC.  The HP C compiler and gcc both implicitly use the
+ *  floating point registers to perform integer multiplies.  If
+ *  a function which you would not think utilize the FP unit DOES,
+ *  then one can not easily predict which tasks will use the FP hardware.
+ *  In this case, this option should be TRUE.
+ *
+ *  If CPU_HARDWARE_FP is FALSE, then this should be FALSE as well.
+ */
+
+#define CPU_ALL_TASKS_ARE_FP     FALSE
+
+/*
+ *  Should the IDLE task have a floating point context?
+ *
+ *  If TRUE, then the IDLE task is created as a RTEMS_FLOATING_POINT task
+ *  and it has a floating point context which is switched in and out.
+ *  If FALSE, then the IDLE task does not have a floating point context.
+ *
+ *  Setting this to TRUE negatively impacts the time required to preempt
+ *  the IDLE task from an interrupt because the floating point context
+ *  must be saved as part of the preemption.
+ */
+
+#define CPU_IDLE_TASK_IS_FP      FALSE
+
+/*
+ *  Should the saving of the floating point registers be deferred
+ *  until a context switch is made to another different floating point
+ *  task?
+ *
+ *  If TRUE, then the floating point context will not be stored until
+ *  necessary.  It will remain in the floating point registers and not
+ *  disturned until another floating point task is switched to.
+ *
+ *  If FALSE, then the floating point context is saved when a floating
+ *  point task is switched out and restored when the next floating point
+ *  task is restored.  The state of the floating point registers between
+ *  those two operations is not specified.
+ *
+ *  If the floating point context does NOT have to be saved as part of
+ *  interrupt dispatching, then it should be safe to set this to TRUE.
+ *
+ *  Setting this flag to TRUE results in using a different algorithm
+ *  for deciding when to save and restore the floating point context.
+ *  The deferred FP switch algorithm minimizes the number of times
+ *  the FP context is saved and restored.  The FP context is not saved
+ *  until a context switch is made to another, different FP task.
+ *  Thus in a system with only one FP task, the FP context will never
+ *  be saved or restored.
+ */
+/*
+ *  ACB Note:  This could make debugging tricky..
+ */
+
+#define CPU_USE_DEFERRED_FP_SWITCH       TRUE
+
+/*
+ *  Does this port provide a CPU dependent IDLE task implementation?
+ *
+ *  If TRUE, then the routine _CPU_Internal_threads_Idle_thread_body
+ *  must be provided and is the default IDLE thread body instead of
+ *  _Internal_threads_Idle_thread_body.
+ *
+ *  If FALSE, then use the generic IDLE thread body if the BSP does
+ *  not provide one.
+ *
+ *  This is intended to allow for supporting processors which have
+ *  a low power or idle mode.  When the IDLE thread is executed, then
+ *  the CPU can be powered down.
+ *
+ *  The order of precedence for selecting the IDLE thread body is:
+ *
+ *    1.  BSP provided
+ *    2.  CPU dependent (if provided)
+ *    3.  generic (if no BSP and no CPU dependent)
+ */
+
+#define CPU_PROVIDES_IDLE_THREAD_BODY    FALSE
+
+/*
+ *  Does the stack grow up (toward higher addresses) or down
+ *  (toward lower addresses)?
+ *
+ *  If TRUE, then the grows upward.
+ *  If FALSE, then the grows toward smaller addresses.
+ */
+
+#define CPU_STACK_GROWS_UP               FALSE
+
+/*
+ *  The following is the variable attribute used to force alignment
+ *  of critical RTEMS structures.  On some processors it may make
+ *  sense to have these aligned on tighter boundaries than
+ *  the minimum requirements of the compiler in order to have as
+ *  much of the critical data area as possible in a cache line.
+ *
+ *  The placement of this macro in the declaration of the variables
+ *  is based on the syntactically requirements of the GNU C
+ *  "__attribute__" extension.  For example with GNU C, use
+ *  the following to force a structures to a 32 byte boundary.
+ *
+ *      __attribute__ ((aligned (32)))
+ *
+ *  NOTE:  Currently only the Priority Bit Map table uses this feature.
+ *         To benefit from using this, the data must be heavily
+ *         used so it will stay in the cache and used frequently enough
+ *         in the executive to justify turning this on.
+ */
+
+#define CPU_STRUCTURE_ALIGNMENT    __attribute__ ((aligned (PPC_CACHE_ALIGNMENT)))
+
+/*
+ *  The following defines the number of bits actually used in the
+ *  interrupt field of the task mode.  How those bits map to the
+ *  CPU interrupt levels is defined by the routine _CPU_ISR_Set_level().
+ */
+/*
+ *  ACB Note: Levels are:
+ *   0: All maskable interrupts enabled
+ *   1: Other critical exceptions enabled
+ *   2: Machine check enabled
+ *   3: All maskable IRQs disabled
+ */
+
+#define CPU_MODES_INTERRUPT_MASK   0x00000003
+
+/*
+ *  Processor defined structures
+ *
+ *  Examples structures include the descriptor tables from the i386
+ *  and the processor control structure on the i960ca.
+ */
+
+/* may need to put some structures here.  */
+
+/*
+ * Contexts
+ *
+ *  Generally there are 2 types of context to save.
+ *     1. Interrupt registers to save
+ *     2. Task level registers to save
+ *
+ *  This means we have the following 3 context items:
+ *     1. task level context stuff::  Context_Control
+ *     2. floating point task stuff:: Context_Control_fp
+ *     3. special interrupt level context :: Context_Control_interrupt
+ *
+ *  On some processors, it is cost-effective to save only the callee
+ *  preserved registers during a task context switch.  This means
+ *  that the ISR code needs to save those registers which do not
+ *  persist across function calls.  It is not mandatory to make this
+ *  distinctions between the caller/callee saves registers for the
+ *  purpose of minimizing context saved during task switch and on interrupts.
+ *  If the cost of saving extra registers is minimal, simplicity is the
+ *  choice.  Save the same context on interrupt entry as for tasks in
+ *  this case.
+ *
+ *  Additionally, if gdb is to be made aware of RTEMS tasks for this CPU, then
+ *  care should be used in designing the context area.
+ *
+ *  On some CPUs with hardware floating point support, the Context_Control_fp
+ *  structure will not be used or it simply consist of an array of a
+ *  fixed number of bytes.   This is done when the floating point context
+ *  is dumped by a "FP save context" type instruction and the format
+ *  is not really defined by the CPU.  In this case, there is no need
+ *  to figure out the exact format -- only the size.  Of course, although
+ *  this is enough information for RTEMS, it is probably not enough for
+ *  a debugger such as gdb.  But that is another problem.
+ */
+
+typedef struct {
+    unsigned32 gpr1;	/* Stack pointer for all */
+    unsigned32 gpr2;	/* TOC in PowerOpen, reserved SVR4, section ptr EABI + */
+    unsigned32 gpr13;	/* First non volatile PowerOpen, section ptr SVR4/EABI */
+    unsigned32 gpr14;	/* Non volatile for all */
+    unsigned32 gpr15;	/* Non volatile for all */
+    unsigned32 gpr16;	/* Non volatile for all */
+    unsigned32 gpr17;	/* Non volatile for all */
+    unsigned32 gpr18;	/* Non volatile for all */
+    unsigned32 gpr19;	/* Non volatile for all */
+    unsigned32 gpr20;	/* Non volatile for all */
+    unsigned32 gpr21;	/* Non volatile for all */
+    unsigned32 gpr22;	/* Non volatile for all */
+    unsigned32 gpr23;	/* Non volatile for all */
+    unsigned32 gpr24;	/* Non volatile for all */
+    unsigned32 gpr25;	/* Non volatile for all */
+    unsigned32 gpr26;	/* Non volatile for all */
+    unsigned32 gpr27;	/* Non volatile for all */
+    unsigned32 gpr28;	/* Non volatile for all */
+    unsigned32 gpr29;	/* Non volatile for all */
+    unsigned32 gpr30;	/* Non volatile for all */
+    unsigned32 gpr31;	/* Non volatile for all */
+    unsigned32 cr;	/* PART of the CR is non volatile for all */
+    unsigned32 pc;	/* Program counter/Link register */
+    unsigned32 msr;	/* Initial interrupt level */
+} Context_Control;
+
+typedef struct {
+    /* The ABIs (PowerOpen/SVR4/EABI) only require saving f14-f31 over
+     * procedure calls.  However, this would mean that the interrupt
+     * frame had to hold f0-f13, and the fpscr.  And as the majority
+     * of tasks will not have an FP context, we will save the whole
+     * context here.
+     */
+#if (PPC_HAS_DOUBLE == 1)
+    double	f[32];
+    double	fpscr;
+#else
+    float	f[32];
+    float	fpscr;
+#endif
+} Context_Control_fp;
+
+typedef struct CPU_Interrupt_frame {
+    unsigned32 stacklink;	/* Ensure this is a real frame (also reg1 save) */
+#if (PPC_ABI == PPC_ABI_POWEROPEN || PPC_ABI == PPC_ABI_GCC27)
+    unsigned32 dummy[13];	/* Used by callees: PowerOpen ABI */
+#else
+    unsigned32 dummy[1];	/* Used by callees: SVR4/EABI */
+#endif
+    /* This is what is left out of the primary contexts */
+    unsigned32 gpr0;
+    unsigned32 gpr2;		/* play safe */
+    unsigned32 gpr3;
+    unsigned32 gpr4;
+    unsigned32 gpr5;
+    unsigned32 gpr6;
+    unsigned32 gpr7;
+    unsigned32 gpr8;
+    unsigned32 gpr9;
+    unsigned32 gpr10;
+    unsigned32 gpr11;
+    unsigned32 gpr12;
+    unsigned32 gpr13;   /* Play safe */
+    unsigned32 gpr28;   /* For internal use by the IRQ handler */
+    unsigned32 gpr29;   /* For internal use by the IRQ handler */
+    unsigned32 gpr30;   /* For internal use by the IRQ handler */
+    unsigned32 gpr31;   /* For internal use by the IRQ handler */
+    unsigned32 cr;	/* Bits of this are volatile, so no-one may save */
+    unsigned32 ctr;
+    unsigned32 xer;
+    unsigned32 lr;
+    unsigned32 pc;
+    unsigned32 msr;
+    unsigned32 pad[3];
+} CPU_Interrupt_frame;
+
+
+/*
+ *  The following table contains the information required to configure
+ *  the PowerPC processor specific parameters.
+ *
+ *  NOTE: The interrupt_stack_size field is required if
+ *        CPU_ALLOCATE_INTERRUPT_STACK is defined as TRUE.
+ *
+ *        The pretasking_hook, predriver_hook, and postdriver_hook,
+ *        and the do_zero_of_workspace fields are required on ALL CPUs.
+ */
+
+typedef struct {
+  void       (*pretasking_hook)( void );
+  void       (*predriver_hook)( void );
+  void       (*postdriver_hook)( void );
+  void       (*idle_task)( void );
+  boolean      do_zero_of_workspace;
+  unsigned32   interrupt_stack_size;
+  unsigned32   extra_system_initialization_stack;
+  unsigned32   clicks_per_usec;	/* Timer clicks per microsecond */
+  unsigned32   serial_per_sec;	/* Serial clocks per second */
+  boolean      serial_external_clock;
+  boolean      serial_xon_xoff;
+  boolean      serial_cts_rts;
+  unsigned32   serial_rate;
+  unsigned32   timer_average_overhead; /* Average overhead of timer in ticks */
+  unsigned32   timer_least_valid; /* Least valid number from timer */
+  void (*spurious_handler)(unsigned32 vector, CPU_Interrupt_frame *);
+}   rtems_cpu_table;
+
+/*
+ *  This variable is optional.  It is used on CPUs on which it is difficult
+ *  to generate an "uninitialized" FP context.  It is filled in by
+ *  _CPU_Initialize and copied into the task's FP context area during
+ *  _CPU_Context_Initialize.
+ */
+
+/* EXTERN Context_Control_fp  _CPU_Null_fp_context; */
+
+/*
+ *  On some CPUs, RTEMS supports a software managed interrupt stack.
+ *  This stack is allocated by the Interrupt Manager and the switch
+ *  is performed in _ISR_Handler.  These variables contain pointers
+ *  to the lowest and highest addresses in the chunk of memory allocated
+ *  for the interrupt stack.  Since it is unknown whether the stack
+ *  grows up or down (in general), this give the CPU dependent
+ *  code the option of picking the version it wants to use.
+ *
+ *  NOTE: These two variables are required if the macro
+ *        CPU_HAS_SOFTWARE_INTERRUPT_STACK is defined as TRUE.
+ */
+
+EXTERN void               *_CPU_Interrupt_stack_low;
+EXTERN void               *_CPU_Interrupt_stack_high;
+
+/*
+ *  With some compilation systems, it is difficult if not impossible to
+ *  call a high-level language routine from assembly language.  This
+ *  is especially true of commercial Ada compilers and name mangling
+ *  C++ ones.  This variable can be optionally defined by the CPU porter
+ *  and contains the address of the routine _Thread_Dispatch.  This
+ *  can make it easier to invoke that routine at the end of the interrupt
+ *  sequence (if a dispatch is necessary).
+ */
+
+/* EXTERN void           (*_CPU_Thread_dispatch_pointer)(); */
+
+/*
+ *  Nothing prevents the porter from declaring more CPU specific variables.
+ */
+
+EXTERN struct {
+#if (PPC_ABI == PPC_ABI_POWEROPEN)
+  unsigned32 Dispatch_r2;
+#else
+  unsigned32 Default_r2;
+#if (PPC_ABI != PPC_ABI_GCC27)
+  unsigned32 Default_r13;
+#endif
+#endif
+  unsigned32 *Nest_level;
+  unsigned32 *Disable_level;
+  void *Vector_table;
+  void *Stack;
+  boolean *Switch_necessary;
+  boolean *Signal;
+} _CPU_IRQ_info CPU_STRUCTURE_ALIGNMENT;
+
+/*
+ *  The size of the floating point context area.  On some CPUs this
+ *  will not be a "sizeof" because the format of the floating point
+ *  area is not defined -- only the size is.  This is usually on
+ *  CPUs with a "floating point save context" instruction.
+ */
+
+#define CPU_CONTEXT_FP_SIZE sizeof( Context_Control_fp )
+
+/*
+ * (Optional) # of bytes for libmisc/stackchk to check
+ * If not specifed, then it defaults to something reasonable
+ * for most architectures.
+ */
+
+#define CPU_STACK_CHECK_SIZE    (128)
+
+/*
+ *  Amount of extra stack (above minimum stack size) required by
+ *  system initialization thread.  Remember that in a multiprocessor
+ *  system the system intialization thread becomes the MP server thread.
+ */
+
+#define CPU_SYSTEM_INITIALIZATION_THREAD_EXTRA_STACK 0
+
+/*
+ *  This defines the number of entries in the ISR_Vector_table managed
+ *  by RTEMS.
+ */
+
+#define CPU_INTERRUPT_NUMBER_OF_VECTORS  (PPC_INTERRUPT_MAX)
+
+/*
+ *  Should be large enough to run all RTEMS tests.  This insures
+ *  that a "reasonable" small application should not have any problems.
+ */
+
+#define CPU_STACK_MINIMUM_SIZE          (1024*3)
+
+/*
+ *  CPU's worst alignment requirement for data types on a byte boundary.  This
+ *  alignment does not take into account the requirements for the stack.
+ */
+
+#define CPU_ALIGNMENT              (PPC_ALIGNMENT)
+
+/*
+ *  This number corresponds to the byte alignment requirement for the
+ *  heap handler.  This alignment requirement may be stricter than that
+ *  for the data types alignment specified by CPU_ALIGNMENT.  It is
+ *  common for the heap to follow the same alignment requirement as
+ *  CPU_ALIGNMENT.  If the CPU_ALIGNMENT is strict enough for the heap,
+ *  then this should be set to CPU_ALIGNMENT.
+ *
+ *  NOTE:  This does not have to be a power of 2.  It does have to
+ *         be greater or equal to than CPU_ALIGNMENT.
+ */
+
+#define CPU_HEAP_ALIGNMENT         (PPC_CACHE_ALIGNMENT)
+
+/*
+ *  This number corresponds to the byte alignment requirement for memory
+ *  buffers allocated by the partition manager.  This alignment requirement
+ *  may be stricter than that for the data types alignment specified by
+ *  CPU_ALIGNMENT.  It is common for the partition to follow the same
+ *  alignment requirement as CPU_ALIGNMENT.  If the CPU_ALIGNMENT is strict
+ *  enough for the partition, then this should be set to CPU_ALIGNMENT.
+ *
+ *  NOTE:  This does not have to be a power of 2.  It does have to
+ *         be greater or equal to than CPU_ALIGNMENT.
+ */
+
+#define CPU_PARTITION_ALIGNMENT    (PPC_CACHE_ALIGNMENT)
+
+/*
+ *  This number corresponds to the byte alignment requirement for the
+ *  stack.  This alignment requirement may be stricter than that for the
+ *  data types alignment specified by CPU_ALIGNMENT.  If the CPU_ALIGNMENT
+ *  is strict enough for the stack, then this should be set to 0.
+ *
+ *  NOTE:  This must be a power of 2 either 0 or greater than CPU_ALIGNMENT.
+ */
+
+#define CPU_STACK_ALIGNMENT        (PPC_STACK_ALIGNMENT)
+
+/* ISR handler macros */
+
+/*
+ *  Disable all interrupts for an RTEMS critical section.  The previous
+ *  level is returned in _level.
+ */
+
+#define _CPU_ISR_Disable( _isr_cookie ) \
+  { \
+    asm volatile ( \
+	"mfmsr %0; andc %1,%0,%1; mtmsr %1" : \
+	"=r" ((_isr_cookie)) : "r" ((PPC_MSR_DISABLE_MASK)) \
+	); \
+  }
+
+/*
+ *  Enable interrupts to the previous level (returned by _CPU_ISR_Disable).
+ *  This indicates the end of an RTEMS critical section.  The parameter
+ *  _level is not modified.
+ */
+
+#define _CPU_ISR_Enable( _isr_cookie )  \
+  { \
+     asm volatile ( "mtmsr %0" : \
+		   "=r" ((_isr_cookie)) : "0" ((_isr_cookie))); \
+  }
+
+/*
+ *  This temporarily restores the interrupt to _level before immediately
+ *  disabling them again.  This is used to divide long RTEMS critical
+ *  sections into two or more parts.  The parameter _level is not
+ * modified.
+ */
+
+#define _CPU_ISR_Flash( _isr_cookie ) \
+  { \
+    asm volatile ( \
+	"mtmsr %0; andc %1,%0,%1; mtmsr %1" : \
+	"=r" ((_isr_cookie)) : \
+	"r" ((PPC_MSR_DISABLE_MASK)), "0" ((_isr_cookie)) \
+	); \
+  }
+
+/*
+ *  Map interrupt level in task mode onto the hardware that the CPU
+ *  actually provides.  Currently, interrupt levels which do not
+ *  map onto the CPU in a generic fashion are undefined.  Someday,
+ *  it would be nice if these were "mapped" by the application
+ *  via a callout.  For example, m68k has 8 levels 0 - 7, levels
+ *  8 - 255 would be available for bsp/application specific meaning.
+ *  This could be used to manage a programmable interrupt controller
+ *  via the rtems_task_mode directive.
+ */
+
+#define _CPU_ISR_Set_level( new_level ) \
+  { \
+    register unsigned32 tmp; \
+    asm volatile ( \
+	"mfmsr %0; andc %0,%0,%1; and %2, %2, %1; or %0, %0, %2; mtmsr %0" : \
+	"=r" ((tmp)) : \
+	"r" ((PPC_MSR_DISABLE_MASK)), "r" ((_CPU_msrs[new_level])), "0" ((tmp)) \
+	); \
+  }
+
+/* end of ISR handler macros */
+
+/* Context handler macros */
+
+/*
+ *  Initialize the context to a state suitable for starting a
+ *  task after a context restore operation.  Generally, this
+ *  involves:
+ *
+ *     - setting a starting address
+ *     - preparing the stack
+ *     - preparing the stack and frame pointers
+ *     - setting the proper interrupt level in the context
+ *     - initializing the floating point context
+ *
+ *  This routine generally does not set any unnecessary register
+ *  in the context.  The state of the "general data" registers is
+ *  undefined at task start time.
+ */
+
+#if PPC_ABI == PPC_ABI_POWEROPEN
+#define _CPU_Context_Initialize( _the_context, _stack_base, _size, \
+                                 _isr, _entry_point ) \
+  { \
+    unsigned32 sp, *desc; \
+    \
+    sp = ((unsigned32)_stack_base) + (_size) - 56; \
+    *((unsigned32 *)sp) = 0; \
+    \
+    desc = (unsigned32 *)_entry_point; \
+    \
+    (_the_context)->msr = PPC_MSR_INITIAL | \
+      _CPU_msrs[ _isr ]; \
+    (_the_context)->pc = desc[0]; \
+    (_the_context)->gpr1 = sp; \
+    (_the_context)->gpr2 = desc[1]; \
+  } 
+#endif
+#if PPC_ABI == PPC_ABI_SVR4
+#define _CPU_Context_Initialize( _the_context, _stack_base, _size, \
+                                 _isr, _entry_point ) \
+  { \
+    unsigned32 sp, r13; \
+    \
+    sp = ((unsigned32)_stack_base) + (_size) - 8; \
+    *((unsigned32 *)sp) = 0; \
+    \
+    asm volatile ("mr %0, 13" : "=r" ((r13))); \
+    \
+    (_the_context->msr) = PPC_MSR_INITIAL | \
+      _CPU_msrs[ _isr ]; \
+    (_the_context->pc) = _entry_point; \
+    (_the_context->gpr1) = sp; \
+    (_the_context->gpr13) = r13; \
+  } 
+#endif
+#if PPC_ABI == PPC_ABI_EABI
+#define _CPU_Context_Initialize( _the_context, _stack_base, _size, \
+                                 _isr, _entry_point ) \
+  { \
+    unsigned32 sp, r2, r13; \
+    \
+    sp = ((unsigned32)_stack_base) + (_size) - 8; \
+    *((unsigned32 *)sp) = 0; \
+    \
+    asm volatile ("mr %0,2; mr %1,13" : "=r" ((r2)), "=r" ((r13))); \
+    \
+    (_the_context)->msr = PPC_MSR_INITIAL | \
+      _CPU_msrs[ _isr ]; \
+    (_the_context->pc) = _entry_point; \
+    (_the_context->gpr1) = sp; \
+    (_the_context->gpr2) = r2; \
+    (_the_context->gpr13) = r13; \
+  } 
+#endif
+
+/*
+ *  This routine is responsible for somehow restarting the currently
+ *  executing task.  If you are lucky, then all that is necessary
+ *  is restoring the context.  Otherwise, there will need to be
+ *  a special assembly routine which does something special in this
+ *  case.  Context_Restore should work most of the time.  It will
+ *  not work if restarting self conflicts with the stack frame
+ *  assumptions of restoring a context.
+ */
+
+#define _CPU_Context_Restart_self( _the_context ) \
+   _CPU_Context_restore( (_the_context) );
+
+/*
+ *  The purpose of this macro is to allow the initial pointer into
+ *  a floating point context area (used to save the floating point
+ *  context) to be at an arbitrary place in the floating point
+ *  context area.
+ *
+ *  This is necessary because some FP units are designed to have
+ *  their context saved as a stack which grows into lower addresses.
+ *  Other FP units can be saved by simply moving registers into offsets
+ *  from the base of the context area.  Finally some FP units provide
+ *  a "dump context" instruction which could fill in from high to low
+ *  or low to high based on the whim of the CPU designers.
+ */
+
+#define _CPU_Context_Fp_start( _base, _offset ) \
+   ( (void *) (_base) + (_offset) )
+
+/*
+ *  This routine initializes the FP context area passed to it to.
+ *  There are a few standard ways in which to initialize the
+ *  floating point context.  The code included for this macro assumes
+ *  that this is a CPU in which a "initial" FP context was saved into
+ *  _CPU_Null_fp_context and it simply copies it to the destination
+ *  context passed to it.
+ *
+ *  Other models include (1) not doing anything, and (2) putting
+ *  a "null FP status word" in the correct place in the FP context.
+ */
+
+#define _CPU_Context_Initialize_fp( _destination ) \
+  { \
+   ((Context_Control_fp *) *((void **) _destination))->fpscr = PPC_INIT_FPSCR; \
+  }
+
+/* end of Context handler macros */
+
+/* Fatal Error manager macros */
+
+/*
+ *  This routine copies _error into a known place -- typically a stack
+ *  location or a register, optionally disables interrupts, and
+ *  halts/stops the CPU.
+ */
+
+#define _CPU_Fatal_halt( _error ) \
+  _CPU_Fatal_error(_error)
+
+/* end of Fatal Error manager macros */
+
+/* Bitfield handler macros */
+
+/*
+ *  This routine sets _output to the bit number of the first bit
+ *  set in _value.  _value is of CPU dependent type Priority_Bit_map_control.
+ *  This type may be either 16 or 32 bits wide although only the 16
+ *  least significant bits will be used.
+ *
+ *  There are a number of variables in using a "find first bit" type
+ *  instruction.
+ *
+ *    (1) What happens when run on a value of zero?
+ *    (2) Bits may be numbered from MSB to LSB or vice-versa.
+ *    (3) The numbering may be zero or one based.
+ *    (4) The "find first bit" instruction may search from MSB or LSB.
+ *
+ *  RTEMS guarantees that (1) will never happen so it is not a concern.
+ *  (2),(3), (4) are handled by the macros _CPU_Priority_mask() and
+ *  _CPU_Priority_Bits_index().  These three form a set of routines
+ *  which must logically operate together.  Bits in the _value are
+ *  set and cleared based on masks built by _CPU_Priority_mask().
+ *  The basic major and minor values calculated by _Priority_Major()
+ *  and _Priority_Minor() are "massaged" by _CPU_Priority_Bits_index()
+ *  to properly range between the values returned by the "find first bit"
+ *  instruction.  This makes it possible for _Priority_Get_highest() to
+ *  calculate the major and directly index into the minor table.
+ *  This mapping is necessary to ensure that 0 (a high priority major/minor)
+ *  is the first bit found.
+ *
+ *  This entire "find first bit" and mapping process depends heavily
+ *  on the manner in which a priority is broken into a major and minor
+ *  components with the major being the 4 MSB of a priority and minor
+ *  the 4 LSB.  Thus (0 << 4) + 0 corresponds to priority 0 -- the highest
+ *  priority.  And (15 << 4) + 14 corresponds to priority 254 -- the next
+ *  to the lowest priority.
+ *
+ *  If your CPU does not have a "find first bit" instruction, then
+ *  there are ways to make do without it.  Here are a handful of ways
+ *  to implement this in software:
+ *
+ *    - a series of 16 bit test instructions
+ *    - a "binary search using if's"
+ *    - _number = 0
+ *      if _value > 0x00ff
+ *        _value >>=8
+ *        _number = 8;
+ *
+ *      if _value > 0x0000f
+ *        _value >=8
+ *        _number += 4
+ *
+ *      _number += bit_set_table[ _value ]
+ *
+ *    where bit_set_table[ 16 ] has values which indicate the first
+ *      bit set
+ */
+
+#define _CPU_Bitfield_Find_first_bit( _value, _output ) \
+  { \
+    asm volatile ("cntlzw %0, %1" : "=r" ((_output)), "=r" ((_value)) : \
+		  "1" ((_value))); \
+  }
+
+/* end of Bitfield handler macros */
+
+/*
+ *  This routine builds the mask which corresponds to the bit fields
+ *  as searched by _CPU_Bitfield_Find_first_bit().  See the discussion
+ *  for that routine.
+ */
+
+#define _CPU_Priority_Mask( _bit_number ) \
+  ( 0x80000000 >> (_bit_number) )
+
+/*
+ *  This routine translates the bit numbers returned by
+ *  _CPU_Bitfield_Find_first_bit() into something suitable for use as
+ *  a major or minor component of a priority.  See the discussion
+ *  for that routine.
+ */
+
+#define _CPU_Priority_Bits_index( _priority ) \
+  (_priority)
+
+/* end of Priority handler macros */
+
+/* variables */
+
+extern const unsigned32 _CPU_msrs[4];
+
+/* functions */
+
+/*
+ *  _CPU_Initialize
+ *
+ *  This routine performs CPU dependent initialization.
+ */
+
+void _CPU_Initialize(
+  rtems_cpu_table  *cpu_table,
+  void      (*thread_dispatch)
+);
+
+/*
+ *  _CPU_ISR_install_vector
+ *
+ *  This routine installs an interrupt vector.
+ */
+
+void _CPU_ISR_install_vector(
+  unsigned32  vector,
+  proc_ptr    new_handler,
+  proc_ptr   *old_handler
+);
+
+/*
+ *  _CPU_Install_interrupt_stack
+ *
+ *  This routine installs the hardware interrupt stack pointer.
+ *
+ *  NOTE:  It need only be provided if CPU_HAS_HARDWARE_INTERRUPT_STACK
+ *         is TRUE.
+ */
+
+void _CPU_Install_interrupt_stack( void );
+
+/*
+ *  _CPU_Context_switch
+ *
+ *  This routine switches from the run context to the heir context.
+ */
+
+void _CPU_Context_switch(
+  Context_Control  *run,
+  Context_Control  *heir
+);
+
+/*
+ *  _CPU_Context_restore
+ *
+ *  This routine is generallu used only to restart self in an
+ *  efficient manner.  It may simply be a label in _CPU_Context_switch.
+ *
+ *  NOTE: May be unnecessary to reload some registers.
+ */
+
+void _CPU_Context_restore(
+  Context_Control *new_context
+);
+
+/*
+ *  _CPU_Context_save_fp
+ *
+ *  This routine saves the floating point context passed to it.
+ */
+
+void _CPU_Context_save_fp(
+  void **fp_context_ptr
+);
+
+/*
+ *  _CPU_Context_restore_fp
+ *
+ *  This routine restores the floating point context passed to it.
+ */
+
+void _CPU_Context_restore_fp(
+  void **fp_context_ptr
+);
+
+void _CPU_Fatal_error(
+  unsigned32 _error
+);
+
+/*  The following routine swaps the endian format of an unsigned int.
+ *  It must be static because it is referenced indirectly.
+ *
+ *  This version will work on any processor, but if there is a better
+ *  way for your CPU PLEASE use it.  The most common way to do this is to:
+ *
+ *     swap least significant two bytes with 16-bit rotate
+ *     swap upper and lower 16-bits
+ *     swap most significant two bytes with 16-bit rotate
+ *
+ *  Some CPUs have special instructions which swap a 32-bit quantity in
+ *  a single instruction (e.g. i486).  It is probably best to avoid
+ *  an "endian swapping control bit" in the CPU.  One good reason is
+ *  that interrupts would probably have to be disabled to insure that
+ *  an interrupt does not try to access the same "chunk" with the wrong
+ *  endian.  Another good reason is that on some CPUs, the endian bit
+ *  endianness for ALL fetches -- both code and data -- so the code
+ *  will be fetched incorrectly.
+ */
+ 
+static inline unsigned int CPU_swap_u32(
+  unsigned int value
+)
+{
+  unsigned32 swapped;
+ 
+  asm volatile("rlwimi %0,%1,8,24,31;"
+	       "rlwimi %0,%1,24,16,23;"
+	       "rlwimi %0,%1,8,8,15;"
+	       "rlwimi %0,%1,24,0,7;" :
+	       "=r" ((swapped)) : "r" ((value)));
+
+  return( swapped );
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif