Truncates the decimal part of positive input or rounds negative
       input.

1  –  Input

       A signed decimal number.

2  –  Output

       A signed decimal number of type G-floating.

3  –  Example

       DTR> PRINT FN$FLOOR (59.99)

         FN$FLOOR

        5.9000E+01

       DTR> PRINT FN$FLOOR (-59.99)

         FN$FLOOR

        -6.0000E+01