src = qnan64: 7ff8000000000000
dst = qnan80: 7fffc000000000000000

src = snan64: 7ff4000000000000
dst = snan80: 7fffbfffffffffffffff

src = qnan80: 7fffc000000000000000
dst = qnan64: 7ff8000000000000

src = snan80: 7fffa000000000000000
dst = snan64: 7ff7ffffffffffff

src = qnan64: fff8000000000000
dst = qnan80: ffffc000000000000000

src = snan64: fff4000000000000
dst = snan80: ffffbfffffffffffffff

src = qnan80: ffffc000000000000000
dst = qnan64: fff8000000000000

src = snan80: ffffa000000000000000
dst = snan64: fff7ffffffffffff