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Added queue handling stuff - NOT INTERRUPT SAFE

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@315 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Linus Nielsen Feltzing 2002-04-29 14:25:44 +00:00
parent 40c1c2251a
commit bd2561dcbb
2 changed files with 46 additions and 0 deletions
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27
firmware/kernel.c
View file

@ -35,3 +35,30 @@ void yield(void)
{ {
switch_thread(); switch_thread();
} }
/****************************************************************************
* Queue handling stuff
****************************************************************************/
void queue_init(struct event_queue *q)
{
q->read = 0;
q->write = 0;
}
struct event *queue_wait(struct event_queue *q)
{
while(q->read == q->write)
{
switch_thread();
}
return &q->events[(q->read++) & QUEUE_LENGTH_MASK];
}
void queue_post(struct event_queue *q, int id, void *data)
{
int wr = (q->write++) & QUEUE_LENGTH_MASK;
q->events[wr].id = id;
q->events[wr].data = data;
}

19
firmware/kernel.h
View file

@ -25,6 +25,22 @@
#define HZ 100 /* number of ticks per second */ #define HZ 100 /* number of ticks per second */
#define QUEUE_LENGTH 16 /* MUST be a power of 2 */
#define QUEUE_LENGTH_MASK (QUEUE_LENGTH - 1)
struct event
{
int id;
void *data;
};
struct event_queue
{
struct event events[QUEUE_LENGTH];
unsigned int read;
unsigned int write;
};
/* global tick variable */ /* global tick variable */
extern long current_tick; extern long current_tick;
@ -32,5 +48,8 @@ extern long current_tick;
extern void yield(void); extern void yield(void);
extern void sleep(int ticks); extern void sleep(int ticks);
extern void queue_init(struct event_queue *q);
extern struct event *queue_wait(struct event_queue *q);
extern void queue_post(struct event_queue *q, int id, void *data);
#endif #endif