EFX_HASH_ROTATE
_c -= EFX_HASH_ROTATE(_b, 16); \
_a -= EFX_HASH_ROTATE(_c, 4); \
_b -= EFX_HASH_ROTATE(_a, 14); \
_c -= EFX_HASH_ROTATE(_b, 24); \
_a ^= EFX_HASH_ROTATE(_c, 4); \
_b ^= EFX_HASH_ROTATE(_a, 6); \
_c ^= EFX_HASH_ROTATE(_b, 8); \
_a ^= EFX_HASH_ROTATE(_c, 16); \
_b ^= EFX_HASH_ROTATE(_a, 19); \
_c ^= EFX_HASH_ROTATE(_b, 4); \
_c -= EFX_HASH_ROTATE(_b, 14); \
_a -= EFX_HASH_ROTATE(_c, 11); \
_b -= EFX_HASH_ROTATE(_a, 25); \