S9fES  (exponent number)  ==>  integer
       (mantissa number)  ==>  integer

EXPONENT returns the exponent of a real number and MANTISSA
returns its mantissa:

        real = (* mantissa (expt 10 exponent))

S9fES stores real numbers in such a format that the mantissa
is always in integer and no trailing (yet significant) zeros
are kept in the mantissa, e.g. 1000.0 would have a mantissa
of 1 and an exponent of 3. This differs from the external
form of real numbers, where exponent and mantissa are scaled
to one single digit in front of the decimal point.

Integers have an exponent of zero and a mantissa that is
equal to their value.

(exponent 12300.0)  ==>  2
(mantissa 12300.0)  ==>  123

(exponent 123.456)  ==>  -3
(mantissa 123.456)  ==>  123456

(exponent 123)  ==>  0
(mantissa 123)  ==>  123
