AT&T 6300 Programmer's Manual page 64

Variable Types
Examples
Examples:
3-6
46.8
-1.09E-06
3489.0
22.5!
A double precision constant is any numeric
constant that has one of the following
characteristics:
• Eight or more digits and a decimal point.
• Exponential form using D.
• A trailing number sign
(#).
345692811
-1.09432D-06
3489.0#
7654321.1234