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/*
* This routine initailizes the periodic interrupt timer on
* the Motorola 68332.
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.org/license/LICENSE.
*/
#include <stdlib.h>
#include <bsp.h>
#include <mrm332.h>
#include <rtems/clockdrv.h>
#include <rtems/m68k/sim.h>
#define CLOCK_VECTOR MRM_PIV
uint32_t Clock_isrs; /* ISRs until next tick */
volatile uint32_t Clock_driver_ticks; /* ticks since initialization */
static rtems_isr_entry Old_ticker;
static void Clock_exit( void );
static rtems_isr Clock_isr(rtems_vector_number vector)
{
Clock_driver_ticks += 1;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
}
else
Clock_isrs -= 1;
}
static void Install_clock(rtems_isr_entry clock_isr)
{
Clock_driver_ticks = 0;
Clock_isrs = rtems_configuration_get_microseconds_per_tick() / 1000;
Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
/* enable 1mS interrupts */
*PITR = (unsigned short int)( SAM(0x09,0,PITM) );/* load counter */
*PICR = (unsigned short int) /* enable interrupt */
( SAM(ISRL_PIT,8,PIRQL) | SAM(CLOCK_VECTOR,0,PIV) );
atexit( Clock_exit );
}
void Clock_exit( void )
{
/* shutdown the periodic interrupt */
*PICR = (unsigned short int)
( SAM(0,8,PIRQL) | SAM(CLOCK_VECTOR,0,PIV) );
/* ^^ zero disables interrupt */
/* do not restore old vector */
}
void _Clock_Initialize( void )
{
Install_clock( Clock_isr );
}
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