Add ao_alarm

diff --git a/src/ao.h b/src/ao.h
index 84e92f35e77ced7eb5c581c6c43230f9eabc110f..b90befe56e8921cc986176bce114bb104f5661bb 100644 (file)
--- a/src/ao.h
+++ b/src/ao.h
@@ -40,6 +40,7 @@
 /* An AltOS task */
 struct ao_task {
        __xdata void *wchan;            /* current wait channel (NULL if running) */
+       uint16_t alarm;                 /* abort ao_sleep time */
        uint8_t stack_count;            /* amount of saved stack */
        uint8_t task_id;                /* index in the task array */
        __code char *name;              /* task name */
@@ -55,8 +56,12 @@ extern __xdata struct ao_task *__data ao_cur_task;
  ao_task.c
  */
 
-/* Suspend the current task until wchan is awoken */
-void
+/* Suspend the current task until wchan is awoken.
+ * returns:
+ *  0 on normal wake
+ *  1 on alarm
+ */
+uint8_t
 ao_sleep(__xdata void *wchan);
 
 /* Wake all tasks sleeping on wchan */
@@ -67,6 +72,10 @@ ao_wakeup(__xdata void *wchan);
 void
 ao_wake_task(__xdata struct ao_task *task);
 
+/* set an alarm to go off in 'delay' ticks */
+void
+ao_alarm(uint16_t delay);
+
 /* Yield the processor to another task */
 void
 ao_yield(void) _naked;

diff --git a/src/ao_task.c b/src/ao_task.c
index 136444b0899ef0b6112544f507f7ca9e8b7d80fa..14aa84c841d698d3a285de7370c80de369c7b56f 100644 (file)
--- a/src/ao_task.c
+++ b/src/ao_task.c
@@ -129,6 +129,13 @@ ao_yield(void) _naked
                                break;
                        }
 
+                       /* Check if the alarm is set for a time which has passed */
+                       if (ao_cur_task->alarm &&
+                           (int16_t) (ao_time() - ao_cur_task->alarm) >= 0) {
+                               ao_cur_task_index = ao_next_task_index;
+                               break;
+                       }
+
                        /* Enter lower power mode when there isn't anything to do */
                        if (ao_next_task_index == ao_cur_task_index)
                                PCON = PCON_IDLE;
@@ -181,13 +188,20 @@ ao_yield(void) _naked
        _endasm;
 }
 
-void
+uint8_t
 ao_sleep(__xdata void *wchan)
 {
        __critical {
                ao_cur_task->wchan = wchan;
        }
        ao_yield();
+       if (ao_cur_task->wchan) {
+               ao_cur_task->wchan = NULL;
+               ao_cur_task->alarm = 0;
+               return 1;
+       }
+       ao_cur_task->alarm = 0;
+       return 0;
 }
 
 void
@@ -200,6 +214,13 @@ ao_wakeup(__xdata void *wchan)
                        ao_tasks[i]->wchan = NULL;
 }
 
+void
+ao_alarm(uint16_t delay)
+{
+       if (!(ao_cur_task->alarm = ao_time() + delay))
+               ao_cur_task->alarm = 1;
+}
+
 void
 ao_wake_task(__xdata struct ao_task *task)
 {