rtapi-atomic-proposal-untested.h

#if defined(__clang__) && __clang__
#define RTAPI_USE_ATOMIC 1
#elif defined(__GNUC__) && (__GNUC__ > 4) && (__GNUC_MINOR__ >= 7)
#define RTAPI_USE_ATOMIC 1
#else
#define RTAPI_USE_ATOMIC 0
#endif

typedef unsigned long rtapi_atomic_type;
#define RTAPI_DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
#define RTAPI_BITS_PER_LONG     (CHAR_BIT * sizeof(rtapi_atomic_type))
#define RTAPI_BIT_MASK(nr)      (1UL << ((nr) % RTAPI_BITS_PER_LONG))
#define RTAPI_BIT_WORD(nr)      ((nr) / RTAPI_BITS_PER_LONG)
#define RTAPI_BITMAP_SIZE(nr)   RTAPI_DIV_ROUND_UP(nr, RTAPI_BITS_PER_LONG)
#define RTAPI_BITMAP_BYTES(nr) \
    (sizeof(rtapi_atomic_type) * RTAPI_BITMAP_SIZE(nr))
#define RTAPI_BIT_SET(a, b)     ((a)[RTAPI_BIT_WORD(b)] |=   RTAPI_BIT_MASK(b))
#define RTAPI_BIT_CLEAR(a, b)   ((a)[RTAPI_BIT_WORD(b)] &= ~ RTAPI_BIT_MASK(b))
#define RTAPI_BIT_TEST(a, b)    ((a)[RTAPI_BIT_WORD(b)] &    RTAPI_BIT_MASK(b))

#define RTAPI_DECLARE_BITMAP(name,bits) \
    rtapi_atomic_type name[RTAPI_BITMAP_SIZE(bits)]
#define RTAPI_ZERO_BITMAP(name,bits) memset(name, 0, RTAPI_BITMAP_BYTES(bits))
#define RTAPI_SET_BITMAP(name,bits) memset(name, ~0, RTAPI_BITMAP_BYTES(bits))

#ifdef RTAPI_USE_ATOMIC
#define RTAPI_MEMORY_MODEL __ATOMIC_SEQ_CST
static inline int rtapi_test_and_set_bit(int nr, void *bitmap)
{
    rtapi_atomic_type *value = (rtapi_atomic_type*)bitmap;
    return (__atomic_fetch_or(value + RTAPI_BIT_WORD(nr),
                    RTAPI_BIT_MASK(nr)) & RTAPI_BIT_MASK(nr),
                    RTAPI_MEMORY_MODEL) != 0;
}
#else
static inline int rtapi_test_and_set_bit(int nr, void *bitmap)
{
    rtapi_atomic_type *value = (rtapi_atomic_type*)bitmap;
    return (__sync_fetch_and_or(value + RTAPI_BIT_WORD(nr),
                    RTAPI_BIT_MASK(nr)) & RTAPI_BIT_MASK(nr)) != 0;
}
#endif