8.6.1.1075 D0< d-zero-less DOUBLE
( d -- flag )
flag is true if and only if d is less than zero.
Testing:
T{ 0. D0< -> <FALSE> }T
T{ 1. D0< -> <FALSE> }T
T{ MIN-INT 0 D0< -> <FALSE> }T
T{ 0 MAX-INT D0< -> <FALSE> }T
T{ MAX-2INT D0< -> <FALSE> }T
T{ -1. D0< -> <TRUE> }T
T{ MIN-2INT D0< -> <TRUE> }T
T{ 1. D0< -> <FALSE> }T
T{ MIN-INT 0 D0< -> <FALSE> }T
T{ 0 MAX-INT D0< -> <FALSE> }T
T{ MAX-2INT D0< -> <FALSE> }T
T{ -1. D0< -> <TRUE> }T
T{ MIN-2INT D0< -> <TRUE> }T