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| 1 | #pypp 0 |
| 2 | // vim: set filetype=cpp : // |
| 3 | // Iris: micro-kernel for a capability-based operating system. |
| 4 | // schedule.ccp: Thread scheduling. |
| 5 | // Copyright 2009 Bas Wijnen <wijnen@debian.org> |
| 6 | // |
| 7 | // This program is free software: you can redistribute it and/or modify |
| 8 | // it under the terms of the GNU General Public License as published by |
| 9 | // the Free Software Foundation, either version 3 of the License, or |
| 10 | // (at your option) any later version. |
| 11 | // |
| 12 | // This program is distributed in the hope that it will be useful, |
| 13 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | // GNU General Public License for more details. |
| 16 | // |
| 17 | // You should have received a copy of the GNU General Public License |
| 18 | // along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 19 | |
| 20 | #include "kernel.hh" |
| 21 | |
| 22 | static void run_thread (kThread *thread): |
| 23 | thread->schedule_next = first_scheduled |
| 24 | if thread->schedule_next: |
| 25 | thread->schedule_next->schedule_prev = thread |
| 26 | thread->schedule_prev = NULL |
| 27 | first_scheduled = thread |
| 28 | |
| 29 | static void unrun_thread (kThread *thread): |
| 30 | if current == thread: |
| 31 | current = thread->schedule_next |
| 32 | if thread->schedule_prev: |
| 33 | thread->schedule_prev->schedule_next = thread->schedule_next |
| 34 | else: |
| 35 | first_scheduled = thread->schedule_next |
| 36 | if thread->schedule_next: |
| 37 | thread->schedule_next->schedule_prev = thread->schedule_prev |
| 38 | |
| 39 | void kThread::run (): |
| 40 | if flags & Iris::Thread::RUNNING: |
| 41 | return |
| 42 | flags |= Iris::Thread::RUNNING |
| 43 | if is_waiting (): |
| 44 | return |
| 45 | run_thread (this) |
| 46 | |
| 47 | void kThread::unrun (): |
| 48 | if !(flags & Iris::Thread::RUNNING): |
| 49 | return |
| 50 | flags &= ~Iris::Thread::RUNNING |
| 51 | if is_waiting (): |
| 52 | return |
| 53 | unrun_thread (this) |
| 54 | |
| 55 | void kThread::unwait (): |
| 56 | flags &= ~Iris::Thread::WAITING |
| 57 | if flags & Iris::Thread::RUNNING: |
| 58 | run_thread (this) |
| 59 | |
| 60 | static void alarm_tick (kReceiver *recv): |
| 61 | if !recv->alarm_count: |
| 62 | // Send message and stop counting. |
| 63 | kCapability::Context c |
| 64 | for unsigned i = 0; i < 2; ++i: |
| 65 | c.data[i] = 0 |
| 66 | recv->send_message (~0, &c) |
| 67 | if recv->prev_alarm: |
| 68 | recv->prev_alarm->next_alarm = recv->next_alarm |
| 69 | else: |
| 70 | first_alarm = recv->next_alarm |
| 71 | if recv->next_alarm: |
| 72 | recv->next_alarm->prev_alarm = recv->prev_alarm |
| 73 | // Fall through to let alarm_count be ~0. This is required, because it is the indicator for no running alarm. |
| 74 | --recv->alarm_count |
| 75 | |
| 76 | void kThread::wait (): |
| 77 | if flags & Iris::Thread::RUNNING: |
| 78 | unrun_thread (this) |
| 79 | flags |= Iris::Thread::WAITING |
| 80 | // Try to receive a message from a kReceiver immediately. |
| 81 | for kReceiver *r = receivers; r; r = r->next_owned: |
| 82 | if r->try_deliver (): |
| 83 | return |
| 84 | |
| 85 | void schedule (): |
| 86 | if current: |
| 87 | current = current->schedule_next |
| 88 | if !current: |
| 89 | current = first_scheduled |
| 90 | |
| 91 | void timer_interrupt (): |
| 92 | kReceiver *recv, *next |
| 93 | for recv = first_alarm; recv; recv = next: |
| 94 | next = (kReceiver *)recv->next_alarm |
| 95 | alarm_tick (recv) |
| 96 | //schedule () |
| 97 |
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