1.1 --- a/extras/mini-os/include/semaphore.h	Thu Jan 17 14:40:23 2008 +0000
     1.2 +++ b/extras/mini-os/include/semaphore.h	Thu Jan 17 14:40:55 2008 +0000
     1.3 @@ -49,6 +49,19 @@ static inline void init_SEMAPHORE(struct
     1.4  
     1.5  #define init_MUTEX(sem) init_SEMAPHORE(sem, 1)
     1.6  
     1.7 +static inline int trydown(struct semaphore *sem)
     1.8 +{
     1.9 +    unsigned long flags;
    1.10 +    int ret = 0;
    1.11 +    local_irq_save(flags);
    1.12 +    if (sem->count > 0) {
    1.13 +        ret = 1;
    1.14 +        sem->count--;
    1.15 +    }
    1.16 +    local_irq_restore(flags);
    1.17 +    return ret;
    1.18 +}
    1.19 +
    1.20  static void inline down(struct semaphore *sem)
    1.21  {
    1.22      unsigned long flags;