2 * Copyright © 2009 Keith Packard <keithp@keithp.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
20 #define AO_NO_TASK_INDEX 0xff
22 __xdata struct ao_task * __xdata ao_tasks[AO_NUM_TASKS];
23 __data uint8_t ao_num_tasks;
24 __data uint8_t ao_cur_task_index;
25 __xdata struct ao_task *__data ao_cur_task;
27 #ifdef ao_arch_task_globals
32 ao_add_task(__xdata struct ao_task * task, void (*start)(void), __code char *name) __reentrant
36 if (ao_num_tasks == AO_NUM_TASKS)
37 ao_panic(AO_PANIC_NO_TASK);
38 for (task_id = 1; task_id != 0; task_id++) {
39 for (t = 0; t < ao_num_tasks; t++)
40 if (ao_tasks[t]->task_id == task_id)
42 if (t == ao_num_tasks)
45 ao_tasks[ao_num_tasks++] = task;
46 task->task_id = task_id;
50 * Construct a stack frame so that it will 'return'
51 * to the start of the task
53 ao_arch_init_stack(task, start);
56 /* Task switching function. This must not use any stack variables */
58 ao_yield(void) ao_arch_naked_define
62 if (ao_cur_task_index == AO_NO_TASK_INDEX)
63 ao_cur_task_index = ao_num_tasks-1;
71 /* Find a task to run. If there isn't any runnable task,
72 * this loop will run forever, which is just fine
75 __pdata uint8_t ao_next_task_index = ao_cur_task_index;
78 if (ao_next_task_index == ao_num_tasks)
79 ao_next_task_index = 0;
81 ao_cur_task = ao_tasks[ao_next_task_index];
82 if (ao_cur_task->wchan == NULL) {
83 ao_cur_task_index = ao_next_task_index;
87 /* Check if the alarm is set for a time which has passed */
88 if (ao_cur_task->alarm &&
89 (int16_t) (ao_time() - ao_cur_task->alarm) >= 0) {
90 ao_cur_task_index = ao_next_task_index;
94 /* Enter lower power mode when there isn't anything to do */
95 if (ao_next_task_index == ao_cur_task_index) {
100 ao_arch_restore_stack();
104 ao_sleep(__xdata void *wchan)
107 ao_cur_task->wchan = wchan;
110 if (ao_cur_task->wchan) {
111 ao_cur_task->wchan = NULL;
118 ao_wakeup(__xdata void *wchan)
122 for (i = 0; i < ao_num_tasks; i++)
123 if (ao_tasks[i]->wchan == wchan)
124 ao_tasks[i]->wchan = NULL;
128 ao_alarm(uint16_t delay)
130 /* Make sure we sleep *at least* delay ticks, which means adding
131 * one to account for the fact that we may be close to the next tick
133 if (!(ao_cur_task->alarm = ao_time() + delay + 1))
134 ao_cur_task->alarm = 1;
140 ao_cur_task->alarm = 0;
149 for (i = ao_cur_task_index; i < ao_num_tasks; i++)
150 ao_tasks[i] = ao_tasks[i+1];
151 ao_cur_task_index = AO_NO_TASK_INDEX;
154 /* we'll never get back here */
161 __xdata struct ao_task *task;
163 for (i = 0; i < ao_num_tasks; i++) {
165 printf("%12s: wchan %04x\n",
172 ao_start_scheduler(void)
174 ao_cur_task_index = AO_NO_TASK_INDEX;