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iris/schedule.ccp
2009-10-10 01:31:10 +02:00

96 lines
2.8 KiB
COBOL

#pypp 0
// Iris: micro-kernel for a capability-based operating system.
// schedule.ccp: Thread scheduling.
// Copyright 2009 Bas Wijnen <wijnen@debian.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "kernel.hh"
static void run_thread (kThread *thread):
thread->schedule_next = first_scheduled
if thread->schedule_next:
thread->schedule_next->schedule_prev = thread
thread->schedule_prev = NULL
first_scheduled = thread
static void unrun_thread (kThread *thread):
if current == thread:
current = thread->schedule_next
if thread->schedule_prev:
thread->schedule_prev->schedule_next = thread->schedule_next
else:
first_scheduled = thread->schedule_next
if thread->schedule_next:
thread->schedule_next->schedule_prev = thread->schedule_prev
void kThread::run ():
if flags & Kernel::Thread::RUNNING:
return
flags |= Kernel::Thread::RUNNING
if is_waiting ():
return
run_thread (this)
void kThread::unrun ():
if !(flags & Kernel::Thread::RUNNING):
return
flags &= ~Kernel::Thread::RUNNING
if is_waiting ():
return
unrun_thread (this)
void kThread::unwait ():
flags &= ~Kernel::Thread::WAITING
if flags & Kernel::Thread::RUNNING:
run_thread (this)
static void alarm_tick (kReceiver *recv):
if !recv->alarm_count:
// Send message and stop counting.
kCapability::Context c
for unsigned i = 0; i < 2; ++i:
c.data[i] = 0
recv->send_message (~0, &c)
if recv->prev_alarm:
recv->prev_alarm->next_alarm = recv->next_alarm
else:
first_alarm = recv->next_alarm
if recv->next_alarm:
recv->next_alarm->prev_alarm = recv->prev_alarm
// Fall through to let alarm_count be ~0. This is required, because it is the indicator for no running alarm.
--recv->alarm_count
void kThread::wait ():
if flags & Kernel::Thread::RUNNING:
unrun_thread (this)
flags |= Kernel::Thread::WAITING
// Try to receive a message from a kReceiver immediately.
for kReceiver *r = receivers; r; r = r->next_owned:
if r->try_deliver ():
return
void schedule ():
if current:
current = current->schedule_next
if !current:
current = first_scheduled
void timer_interrupt ():
kReceiver *recv, *next
for recv = first_alarm; recv; recv = next:
next = (kReceiver *)recv->next_alarm
alarm_tick (recv)
//schedule ()