Implementation of missing lockable instructions

stdatomic.h

#include <stdbool.h>
#include <stdint.h>

typedef __int128 int128_t;
typedef unsigned __int128 uint128_t;

#define atomic_fetch_adc(object, argument)                                     \
  ({                                                                           \
    asm("lock adc %0, %1"                                                      \
        : "+m"(*(object)), "+r"(argument)                                      \
        :                                                                      \
        : "memory", "cc");                                                     \
  })

#define atomic_fetch_sbb(object, argument)                                     \
  ({                                                                           \
    asm("lock sbb %0, %1"                                                      \
        : "+m"(*(object)), "+r"(argument)                                      \
        :                                                                      \
        : "memory", "cc");                                                     \
  })

#if defined(__GCC_ASM_FLAG_OUTPUTS__)
#define atomic_bit_test_clear(object, argument)                                \
  ({                                                                           \
    bool result;                                                               \
    asm("lock btc %0, %2"                                                      \
        : "+m"(*(object)), "=@ccc"(result)                                     \
        : "r"(argument)                                                        \
        : "memory", "cc");                                                     \
    result;                                                                    \
  })

#define atomic_bit_test_reset(object, argument)                                \
  ({                                                                           \
    bool result;                                                               \
    asm("lock btr %0, %2"                                                      \
        : "+m"(*(object)), "=@ccc"(result)                                     \
        : "r"(argument)                                                        \
        : "memory", "cc");                                                     \
    result;                                                                    \
  })

#define atomic_bit_test_set(object, argument)                                  \
  ({                                                                           \
    bool result;                                                               \
    asm("lock bts %0, %2"                                                      \
        : "+m"(*(object)), "=@ccc"(result)                                     \
        : "r"(argument)                                                        \
        : "memory", "cc");                                                     \
    result;                                                                    \
  })

inline bool atomic_compare_exchange_eight_bytes(uint64_t *object,
                                                uint32_t *expected_low,
                                                uint32_t *expected_high,
                                                uint32_t desired_low,
                                                uint32_t desired_high) {
  bool result;
  asm("lock cmpxchg8b %0"
      : "+m"(*object), "+d"(expected_high), "+a"(expected_low), "=@ccz"(result)
      : "c"(desired_high), "b"(desired_low)
      : "memory", "cc");
  return result;
}

inline bool atomic_compare_exchange_sixteen_bytes(uint128_t *object,
                                                  uint64_t *expected_low,
                                                  uint64_t *expected_high,
                                                  uint64_t desired_low,
                                                  uint64_t desired_high) {
  bool result;
  asm("lock cmpxchg16b %0"
      : "+m"(*object), "+d"(expected_high), "+a"(expected_low), "=@ccz"(result)
      : "c"(desired_high), "b"(desired_low)
      : "memory", "cc");
  return result;
}
#endif