EVENT intern forcedevent( void )
/******************************/
/* This function should ONLY be called from the uieventsource function */
{
EVENT ev;
// enter critical section
if( _queue_is_empty( Forced_Q ) ) {
ev = EV_NO_EVENT;
} else {
_queue_remove( Forced_Q, &ev );
}
// exit critical section
return( ev );
}
static void _clock_isr( int vector, int code ) {
(void)(vector);
(void)(code);
pcb_t *pcb;
// spin the pinwheel
++_pinwheel;
if( _pinwheel == (CLOCK_FREQUENCY / 10) ) {
_pinwheel = 0;
++_pindex;
c_putchar_at( 79, 0, "|/-\\"[ _pindex & 3 ] );
}
// increment the system time
++_system_time;
/*
** wake up any sleeper whose time has come
**
** we give awakened processes preference over the
** current process (when it is scheduled again)
*/
while( !_queue_empty(_sleeping) &&
(uint32_t) _queue_kpeek(_sleeping) <= _system_time ) {
// time to wake up! remove it from the queue
pcb = (pcb_t *) _queue_remove( _sleeping );
if( pcb == NULL ) {
#ifdef DEBUG
_kpanic( "_clock_isr", "NULL from sleep queue remove" );
#else
c_puts( "*** _clock_isr: NULL from sleep queue\n" );
break;
#endif
}
// and schedule it for dispatch
_schedule( pcb );
}
// check the current process to see if it needs to be scheduled
// sanity check!
_current->quantum -= 1;
if( _current->quantum < 1 ) {
_schedule( _current );
_dispatch();
}
#ifdef DUMP_QUEUES
// Approximately every 10 seconds, dump the queues, and
// print the contents of the SIO buffers.
if( (_system_time % SECONDS_TO_TICKS(10)) == 0 ) {
c_printf( "Queue contents @%08x\n", _system_time );
_queue_dump( "ready[0]", _ready[0] );
_queue_dump( "ready[1]", _ready[1] );
_queue_dump( "ready[2]", _ready[2] );
_queue_dump( "ready[3]", _ready[3] );
_queue_dump( "sleep", _sleeping );
_sio_dump();
}
#endif
// tell the PIC we're done
__outb( PIC_MASTER_CMD_PORT, PIC_EOI );
}
