int probe_8259() {
unsigned char om,cm,c2;
unsigned int flags;
if (p8259_probed < 0)
return (int)p8259_probed;
/* don't let the BIOS fiddle with the mask during
the test. Fixes: Pentium machine where 1 out of
100 times programs fail with "cannot init PIC" */
flags = get_cpu_flags(); _cli();
om = p8259_read_mask(0);
p8259_write_mask(0,0xFF);
cm = p8259_read_mask(0);
p8259_write_mask(0,0x00);
c2 = p8259_read_mask(0);
p8259_write_mask(0,om);
set_cpu_flags(flags);
if (cm != 0xFF || c2 != 0x00)
return (p8259_probed=0);
/* is a slave present too? */
flags = get_cpu_flags(); _cli();
om = p8259_read_mask(8);
p8259_write_mask(8,0xFF);
cm = p8259_read_mask(8);
p8259_write_mask(8,0x00);
c2 = p8259_read_mask(8);
p8259_write_mask(8,om);
set_cpu_flags(flags);
if (cm == 0xFF && c2 == 0x00)
p8259_slave_present = 1;
return (p8259_probed=1);
}
void scheduler()
{
unsigned int cpu_id = CPUID;
struct scheduler_info *si = &(cpu[ cpu_id ].sched);
struct thread *tr;
int idle;
int flip = 0;
uint64_t requested_time = TIMESLICE;
// We will never go back.
set_cpu_flags( cpu_flags() & ~EFLAG_NESTED_TASK );
// Now we're working.
acquire_spinlock( &(si->lock_scheduler) );
// Start timing the scheduler
stats_time_start( &(cpu[ cpu_id ].st_schedulerTime) );
assert( (cpu_flags() & EFLAG_INTERRUPT) == 0 );
ack_apic();
while (1==1)
{
// Just show the world that we're still alive.
((char*)0xB8000)[158 - cpu_id * 2] ++ ; /// \todo remove one day
// If the garbage collector has work to do, let it run.
if ( gc_has_work( cpu_id ) == 0 )
{
tr = smk_gc[ cpu_id ];
exec_thread( cpu_id, tr, TIMESLICE, 0 );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
}
// Find out when the next timed event is.
requested_time = remove_timers( si, cpu[ cpu_id ].st_systemTime.usage );
idle = 0;
// Fast queue support
if ( flip == 0 )
{
tr = get_fast( si );
if ( tr != NULL )
{
exec_thread( cpu_id, tr, TIMESLICE, 0 );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
// Maintain CPU time.
if ( si->sched_count != 0 ) flip = 1; // Ensure others run
continue;
}
}
flip = 0;
// Reset of fast queue
// If there's nothing to do, do idle.
if ( si->sched_count == 0 )
{
if ( gc_has_work( cpu_id ) == 0 ) continue; // Al-e-oop!
tr = smk_idle[ cpu_id ];
idle = 1; // Safe to wake up when required.
}
else
{
tr = si->sched_queue[ si->position ].tr;
si->position = (si->position + 1) % si->sched_count;
requested_time = TIMESLICE;
idle = 0; // Don't interrupt until timeslice is over
}
// And run the selected thread.
exec_thread( cpu_id, tr, requested_time, idle );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
// Maintain CPU time.
//
// If the previous thread requested a state change, honour it.
remove_last( si );
}
}
