source: rtems/cpukit/score/cpu/nios2/cpu.c @ 3c87adba

/*
 *  NIOS2 CPU Dependent Source
 *
 *  COPYRIGHT (c) 1989-2006
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.com/license/LICENSE.
 *
 *  $Id$
 */

#include <rtems/system.h>
#include <rtems/score/isr.h>
#include <rtems/score/wkspace.h>

/*  _CPU_Initialize
 *
 *  This routine performs processor dependent initialization.
 *
 *  INPUT PARAMETERS:
 *    thread_dispatch - address of disptaching routine
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */


void _CPU_Initialize(
  void      (*thread_dispatch)      /* ignored on this CPU */
)
{
  /*
   *  The thread_dispatch argument is the address of the entry point
   *  for the routine called at the end of an ISR once it has been
   *  decided a context switch is necessary.  On some compilation
   *  systems it is difficult to call a high-level language routine
   *  from assembly.  This allows us to trick these systems.
   *
   *  If you encounter this problem save the entry point in a CPU
   *  dependent variable.
   */

  _CPU_Thread_dispatch_pointer = thread_dispatch;

  /*
   *  If there is not an easy way to initialize the FP context
   *  during Context_Initialize, then it is usually easier to
   *  save an "uninitialized" FP context here and copy it to
   *  the task's during Context_Initialize.
   */

  /* FP context initialization support goes here */
}

/*PAGE
 *
 *  _CPU_ISR_Get_level
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */
 
uint32_t   _CPU_ISR_Get_level( void )
{
  /*
   *  This routine returns the current interrupt level.
   */

  return 0;
}

/*PAGE
 *
 *  _CPU_ISR_install_raw_handler
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */
 
void _CPU_ISR_install_raw_handler(
  uint32_t    vector,
  proc_ptr    new_handler,
  proc_ptr   *old_handler
)
{
  /*
   *  This is where we install the interrupt handler into the "raw" interrupt
   *  table used by the CPU to dispatch interrupt handlers.
   */
}

/*PAGE
 *
 *  _CPU_ISR_install_vector
 *
 *  This kernel routine installs the RTEMS handler for the
 *  specified vector.
 *
 *  Input parameters:
 *    vector      - interrupt vector number
 *    old_handler - former ISR for this vector number
 *    new_handler - replacement ISR for this vector number
 *
 *  Output parameters:  NONE
 *
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */

void _CPU_ISR_install_vector(
  uint32_t    vector,
  proc_ptr    new_handler,
  proc_ptr   *old_handler
)
{
   *old_handler = _ISR_Vector_table[ vector ];

   /*
    *  If the interrupt vector table is a table of pointer to isr entry
    *  points, then we need to install the appropriate RTEMS interrupt
    *  handler for this vector number.
    */

   _CPU_ISR_install_raw_handler( vector, new_handler, old_handler );

   /*
    *  We put the actual user ISR address in '_ISR_vector_table'.  This will
    *  be used by the _ISR_Handler so the user gets control.
    */

    _ISR_Vector_table[ vector ] = new_handler;
}

/*PAGE
 *
 *  _CPU_Install_interrupt_stack
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */

void _CPU_Install_interrupt_stack( void )
{
}

/*PAGE
 *
 *  _CPU_Thread_Idle_body
 *
 *  NOTES:
 *
 *  1. This is the same as the regular CPU independent algorithm.
 *
 *  2. If you implement this using a "halt", "idle", or "shutdown"
 *     instruction, then don't forget to put it in an infinite loop.
 *
 *  3. Be warned. Some processors with onboard DMA have been known
 *     to stop the DMA if the CPU were put in IDLE mode.  This might
 *     also be a problem with other on-chip peripherals.  So use this
 *     hook with caution.
 *
 *  NO_CPU Specific Information:
 *
 *  XXX document implementation including references if appropriate
 */

void *_CPU_Thread_Idle_body( uint32_t ignored )
{
#if 1
  for(;;);
#else
  for(;;)
  {
    uint32_t st = __builtin_rdctl(0); /* read status  register */

    /* Differentiate between IRQ off and on (for debugging) */
    if(st & 1)
      for(;;); 
    else
      for(;;); 
 
    /* insert your "halt" instruction here */ ;
  }
#endif
}