COBOL - USAGE Clause - COMPUTATIONAL-2 or COMP-2 (long floating-point)
The COMPUTATIONAL-2 or COMP-2 phrase is specified for internal floating-point items (double precision).
COMP-2 items are 8 bytes long.
The sign is contained in the first bit of the leftmost byte and the next 11 bits contain the exponent.
The remaining 52 bits contain the mantissa.
For conditional expressions, the class condition cannot be used for COMPUTATIONAL-2 or COMP-2 internal floating-point data items.
