Make protothread semaphores interrupt-safe.

This commit is contained in:
Ian Martin 2014-06-11 18:44:59 -04:00
parent cff30a394b
commit e5add3d1f8

View file

@ -162,9 +162,11 @@ PT_THREAD(driver_thread(struct pt *pt))
#include "sys/pt.h" #include "sys/pt.h"
struct pt_sem { struct pt_sem {
unsigned int count; unsigned int head, tail;
}; };
#define PT_SEM_COUNT(s) ((s)->head - (s)->tail)
/** /**
* Initialize a semaphore * Initialize a semaphore
* *
@ -179,7 +181,11 @@ struct pt_sem {
* \param c (unsigned int) The initial count of the semaphore. * \param c (unsigned int) The initial count of the semaphore.
* \hideinitializer * \hideinitializer
*/ */
#define PT_SEM_INIT(s, c) (s)->count = c #define PT_SEM_INIT(s, c) \
do { \
(s)->tail = 0; \
(s)->head = (c); \
} while(0)
/** /**
* Wait for a semaphore * Wait for a semaphore
@ -199,8 +205,8 @@ struct pt_sem {
*/ */
#define PT_SEM_WAIT(pt, s) \ #define PT_SEM_WAIT(pt, s) \
do { \ do { \
PT_WAIT_UNTIL(pt, (s)->count > 0); \ PT_WAIT_UNTIL(pt, PT_SEM_COUNT(s) > 0); \
--(s)->count; \ ++(s)->tail; \
} while(0) } while(0)
/** /**
@ -218,7 +224,7 @@ struct pt_sem {
* *
* \hideinitializer * \hideinitializer
*/ */
#define PT_SEM_SIGNAL(pt, s) ++(s)->count #define PT_SEM_SIGNAL(pt, s) (++(s)->head)
#endif /* PT_SEM_H_ */ #endif /* PT_SEM_H_ */