(42S) Three-Way Comparison, <=>, compare for Reals & a Problem on Free42

[Gerald H]

For reals input

A
B

the programme returns for

A<B
-1

A=B
0

A>B
1

The programme poses no problems on the real HP 42S, however on Free42 the programme cannot be entered, or at any rate I haven't managed it, as after entering the "3" in the label I can't enter any alpha characters.

Any hints how to do this?

Code:

00 { 11-Byte Prgm }
01▸LBL "3WCP"
02 -
03 X≠0?
04 SIGN
05 .END.