xormor basic 2.0 c64 cbmbasic

$ ./cbmbasic

    **** COMMODORE 64 BASIC V2 ****

 64K RAM SYSTEM  38911 BASIC BYTES FREE

READY.
10 DEF FN DBL(X) = X + X
20 PRINT FN DBL(2)
RUN
 4

READY.
20 PRINT FN DBL(20)
RUN
 40

READY.
20 PRINT FN DBL(-2)
RUN
-4

READY.
20 PRINT FN DBL(-20)
RUN
-40

READY.
PRINT FN DBL(-3)
-6

READY.
PRINT FN DBL(-1.25)
-2.5

READY.
PRINT FN DBL(-0.3333333333)
-.666666667

READY.
print fn dbl(-2.5)

?SYNTAX  ERROR
READY.
PRINT FN DBL(-2.5)
-5

READY.
PRINT FN DBL(-1.234567)
-2.469134

READY.
PRINT FN DBL(-0.8888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888)

?STRING TOO LONG  ERROR
READY.

?SYNTAX  ERROR
READY.
PRINT FN DBL(-0.88888888888888888888888888888888888)
-1.77777778

READY.