Subversion Repositories Kolibri OS

#define RWSEM_UNLOCKED_VALUE            0x00000000L

#define RWSEM_ACTIVE_BIAS               0x00000001L

#define RWSEM_WAITING_BIAS              (-RWSEM_ACTIVE_MASK-1)

#define RWSEM_ACTIVE_READ_BIAS          RWSEM_ACTIVE_BIAS

#define RWSEM_ACTIVE_WRITE_BIAS         (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)

static inline int down_read_trylock(struct rw_semaphore *sem)

{

    long result, tmp;

    asm volatile("# beginning __down_read_trylock\n\t"

                 "  mov          %0,%1\n\t"

                 "1:\n\t"

                 "  mov          %1,%2\n\t"

                 "  add          %3,%2\n\t"

                 "  jle          2f\n\t"

                 LOCK_PREFIX "  cmpxchg  %2,%0\n\t"

                 "  jnz          1b\n\t"

                 "2:\n\t"

                 "# ending __down_read_trylock\n\t"

                 : "+m" (sem->count), "=&a" (result), "=&r" (tmp)

                 : "i" (RWSEM_ACTIVE_READ_BIAS)

                 : "memory", "cc");

    return result >= 0 ? 1 : 0;

}