usermode/library/atomic_ops/standard_ao_double_t.h

/* NEC LE-IT: For 64Bit OS we extend the double type to hold two int64's
*
*  x86-64: __m128 serves as placeholder which also requires the compiler
*          to align     it on 16 byte boundary (as required by cmpxchg16.
* Similar things could be done for PowerPC 64bit using a VMX data type...       */

#if (defined(__x86_64__) && defined(__GNUC__)) || defined(_WIN64)
# include <xmmintrin.h>
  typedef __m128 double_ptr_storage;
#elif defined(_WIN32) && !defined(__GNUC__)
  typedef unsigned __int64 double_ptr_storage;
#else
  typedef unsigned long long double_ptr_storage;
#endif

# define AO_HAVE_DOUBLE_PTR_STORAGE

typedef union {
    double_ptr_storage AO_whole;
    struct {AO_t AO_v1; AO_t AO_v2;} AO_parts;
} AO_double_t;

#define AO_HAVE_double_t
#define AO_val1 AO_parts.AO_v1
#define AO_val2 AO_parts.AO_v2

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