1#define a_cas(p, t, s) (__sync_val_compare_and_swap((p), (t), (s))) 2#define a_crash() (__builtin_trap()) 3#define a_clz_32 __builtin_clz 4#define a_clz_64 __builtin_clzll 5#define a_ctz_32 __builtin_ctz 6#define a_ctz_64 __builtin_ctzll