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iris/schedule.ccp
2009-07-05 10:52:44 +02:00

129 lines
3.5 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 (Thread *thread):
thread->schedule_next = first_scheduled
if thread->schedule_next:
thread->schedule_next->schedule_prev = thread
first_scheduled = thread
static void unrun_thread (Thread *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 Thread::sleep ():
schedule_next = first_sleeper
if schedule_next:
schedule_next->schedule_prev = this
schedule_prev = NULL
first_sleeper = this
void Thread::unsleep ():
if schedule_next:
schedule_next->schedule_prev = schedule_prev
if schedule_prev:
schedule_prev->schedule_next = schedule_next
else:
first_sleeper = schedule_next
void Thread::run ():
if flags & THREAD_FLAG_RUNNING:
return
flags |= THREAD_FLAG_RUNNING
if flags & THREAD_FLAG_WAITING:
if sleep_count != ~0:
sleep ()
return
run_thread (this)
void Thread::unrun ():
if !(flags & THREAD_FLAG_RUNNING):
return
flags &= ~THREAD_FLAG_RUNNING
if flags & THREAD_FLAG_WAITING:
if sleep_count != ~0:
unsleep ()
return
unrun_thread (this)
void Thread::unwait ():
if !(flags & THREAD_FLAG_WAITING):
return
flags &= ~THREAD_FLAG_WAITING
if sleep_count != ~0:
unsleep ()
if flags & THREAD_FLAG_RUNNING:
run_thread (this)
static void sleep_tick (Thread *thread):
if !thread->sleep_count:
thread->unwait ()
// Time-out: let the thread know with a special message.
Capability::Context c
for unsigned i = 0; i < 4; ++i:
c.data[i] = 0
c.cap[i] = NULL
c.copy[i] = false
Thread_arch_receive (thread, ~0, &c)
// Fall through to let sleep be set to ~0, so the next wait will be infinitely long again.
--thread->sleep_count
void Thread::wait ():
if flags & THREAD_FLAG_WAITING:
return
if flags & THREAD_FLAG_RUNNING:
unrun_thread (this)
flags |= THREAD_FLAG_WAITING
if sleep_count != ~0:
sleep ()
// Try to receive a message from a Receiver immediately.
for Receiver *r = receivers; r; r = r->next_owned:
if r->try_deliver ():
return
if sleep_count != ~0:
sleep_tick (this)
void schedule ():
Thread *old = current
if current:
current = current->schedule_next
if !current:
current = first_scheduled
if !current:
current = &idle
void timer_interrupt ():
//panic (0x88877744, "Timer interrupt")
Thread *thread, *next
for thread = first_sleeper; thread; thread = next:
next = thread->next
sleep_tick (thread)
schedule ()
//#ifndef NDEBUG
//static bool ledstate = false
//dbg_led (false, false, ledstate = !ledstate)
//#endif