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Add 64 bit byte swapping function

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Jonathan G Rennison
2018-05-28 02:20:30 +01:00
parent b90c5b9618
commit 9ca4e915ba
2 changed files with 27 additions and 0 deletions
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19
src/core/bitmath_func.hpp
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@@ -365,13 +365,32 @@ static inline T ROR(const T x, const uint8 n)
* (since it will use hardware swapping if available).
* Even though they should return uint16 and uint32, we get
* warnings if we don't cast those (why?) */
#define BSWAP64(x) ((uint32)CFSwapInt64(x))
#define BSWAP32(x) ((uint32)CFSwapInt32(x))
#define BSWAP16(x) ((uint16)CFSwapInt16(x))
#elif defined(_MSC_VER)
/* MSVC has intrinsics for swapping, resulting in faster code */
#define BSWAP64(x) (_byteswap_uint64(x))
#define BSWAP32(x) (_byteswap_ulong(x))
#define BSWAP16(x) (_byteswap_ushort(x))
#else
/**
* Perform a 64 bits endianness bitswap on x.
* @param x the variable to bitswap
* @return the bitswapped value.
*/
static inline uint64 BSWAP64(uint64 x)
{
#if !defined(__ICC) && (defined(__GNUC__) || defined(__clang__))
/* GCC >= 4.3 provides a builtin, resulting in faster code */
return (uint64)__builtin_bswap64((uint64)x);
#else
return ((x >> 56) & 0xFFULL) | ((x >> 40) & 0xFF00ULL) | ((x >> 24) & 0xFF0000ULL) | ((x >> 8) & 0xFF000000ULL) |
((x << 8) & 0xFF00000000ULL) | ((x << 24) & 0xFF0000000000ULL) | ((x << 40) & 0xFF000000000000ULL) | ((x << 56) & 0xFF000000000000ULL);
;
#endif /* __GNUC__ || __clang__ */
}
/**
* Perform a 32 bits endianness bitswap on x.
* @param x the variable to bitswap