cpu.c

RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating sys

/*
 *  Motorola MC68xxx Dependent Source
 *
 *  COPYRIGHT (c) 1989-1999.
 *  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: cpu.c,v 1.22.2.1 2003/09/04 18:47:28 joel Exp $
 */

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

/*  _CPU_Initialize
 *
 *  This routine performs processor dependent initialization.
 *
 *  INPUT PARAMETERS:
 *    cpu_table       - CPU table to initialize
 *    thread_dispatch - entry pointer to thread dispatcher
 *
 *  OUTPUT PARAMETERS: NONE
 */

void _CPU_Initialize(
  rtems_cpu_table  *cpu_table,
  void      (*thread_dispatch)      /* ignored on this CPU */
)
{
#if ( M68K_HAS_VBR == 0 )
  /* fill the isr redirect table with the code to place the format/id
     onto the stack */

  unsigned32 slot;

  for (slot = 0; slot < CPU_INTERRUPT_NUMBER_OF_VECTORS; slot++)
  {
    _CPU_ISR_jump_table[slot].move_a7 = M68K_MOVE_A7;
    _CPU_ISR_jump_table[slot].format_id = slot << 2;
    _CPU_ISR_jump_table[slot].jmp = M68K_JMP;
    _CPU_ISR_jump_table[slot].isr_handler = (unsigned32) 0xDEADDEAD;
  }
#endif /* M68K_HAS_VBR */

  _CPU_Table = *cpu_table;
}

/*PAGE
 *
 *  _CPU_ISR_Get_level
 */
 
unsigned32 _CPU_ISR_Get_level( void )
{
  unsigned32 level;

  m68k_get_interrupt_level( level );

  return level;
}

/*PAGE
 *
 *  _CPU_ISR_install_raw_handler
 */
 
void _CPU_ISR_install_raw_handler(
  unsigned32  vector,
  proc_ptr    new_handler,
  proc_ptr   *old_handler
)
{
  proc_ptr *interrupt_table = NULL;

#if (M68K_HAS_FPSP_PACKAGE == 1)
  /*
   *  If this vector being installed is one related to FP, then the
   *  FPSP will install the handler itself and handle it completely
   *  with no intervention from RTEMS.
   */

  if (*_FPSP_install_raw_handler &&
      (*_FPSP_install_raw_handler)(vector, new_handler, *old_handler))
        return;
#endif


  /*
   *  On CPU models without a VBR, it is necessary for there to be some
   *  header code for each ISR which saves a register, loads the vector
   *  number, and jumps to _ISR_Handler. 
   */

  m68k_get_vbr( interrupt_table );
#if ( M68K_HAS_VBR == 1 )
  *old_handler = interrupt_table[ vector ];
  interrupt_table[ vector ] = new_handler;
#else

  /*
   *  Install handler into RTEMS jump table and if VBR table is in
   *  RAM, install the pointer to the appropriate jump table slot.
   *  If the VBR table is in ROM, it is the BSP's responsibility to
   *  load it appropriately to vector to the RTEMS jump table.
   */

  *old_handler = (proc_ptr) _CPU_ISR_jump_table[vector].isr_handler;
  _CPU_ISR_jump_table[vector].isr_handler = (unsigned32) new_handler;
  if ( (unsigned32) interrupt_table != 0xFFFFFFFF )
    interrupt_table[ vector ] = (proc_ptr) &_CPU_ISR_jump_table[vector];
#endif /* M68K_HAS_VBR */
}

/*PAGE
 *
 *  _CPU_ISR_install_vector
 *
 *  This kernel routine installs the RTEMS handler for the
 *  specified vector.
 *
 *  Input parameters:
 *    vector      - interrupt vector number
 *    new_handler - replacement ISR for this vector number
 *    old_handler - former ISR for this vector number
 *
 *  Output parameters:  NONE
 */

void _CPU_ISR_install_vector(
  unsigned32  vector,
  proc_ptr    new_handler,
  proc_ptr   *old_handler
)
{
  proc_ptr ignored;

  *old_handler = _ISR_Vector_table[ vector ];

  _CPU_ISR_install_raw_handler( vector, _ISR_Handler, &ignored );

  _ISR_Vector_table[ vector ] = new_handler;
}


/*PAGE
 *
 *  _CPU_Install_interrupt_stack
 */

void _CPU_Install_interrupt_stack( void )
{
#if ( M68K_HAS_SEPARATE_STACKS == 1 )
  void *isp = _CPU_Interrupt_stack_high;

  asm volatile ( "movec %0,%%isp" : "=r" (isp) : "0" (isp) );
#endif
}

#if ( M68K_HAS_BFFFO != 1 )
/*
 * Returns table for duplication of the BFFFO instruction (16 bits only)
 */
const unsigned char __BFFFOtable[256] = {
    8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
#endif

/*PAGE
 *
 *  The following code context switches the software FPU emulation
 *  code provided with GCC.
 */

#if (CPU_SOFTWARE_FP == TRUE)
extern Context_Control_fp _fpCCR;

void CPU_Context_save_fp (void **fp_context_ptr)
{
  Context_Control_fp *fp;

  fp = (Context_Control_fp *) *fp_context_ptr;

  *fp = _fpCCR;
}

void CPU_Context_restore_fp (void **fp_context_ptr)
{
  Context_Control_fp *fp;

  fp = (Context_Control_fp *) *fp_context_ptr;

  _fpCCR = *fp;
}
#endif