(exp (ldb sb!vm:double-float-exponent-byte hi-bits))
(frac (logior (ldb sb!vm:double-float-significand-byte hi-bits)
sb!vm:double-float-hidden-bit))
(exp (ldb sb!vm:double-float-exponent-byte hi-bits))
(frac (logior (ldb sb!vm:double-float-significand-byte hi-bits)
sb!vm:double-float-hidden-bit))