COMPUTATIONAL-X and COMPUTATIONAL-5 Formats

These formats are as for COMPUTATIONAL format except for the differences given below. See the section COMPUTATIONAL, BINARY, or COMPUTATIONAL-4 Format.

They both differ in the following ways from the COMPUTATIONAL format:

• The PICTURE character-string can consist of all "x"s. If it does, the number of "x"s gives the length of the item in bytes.
• Whether the PICTURE character-string consists of "x" s or "9"s, the value that can be stored is limited to the largest binary number for which the allocated storage has space. The item is not affected by the TRUNC, COMP, and ALIGN Compiler directives. However, there is still a maximum of 18 digits which can be specified (either up to eighteen "9"s or up to eight "x"s in the PICTURE clause). If the compiler directive INTLEVEL(4) is specified, the maximum is 38 digits (either thirty-eight "9"s or sixteen "x"s).
• The number of "9"s in the PICTURE character string affect the run-time element if the item is a destination field in an arithmetic operation including an ON SIZE ERROR or NOT ON SIZE ERROR clause: the number of "9"s determines whether or not a size error condition is deemed to have arisen due to a decimal digit overflow. When either clause is present, only arithmetic results falling within this range, that is, not causing a size error, are stored.
• The following are the only differences between COMPUTATIONAL-X and COMPUTATIONAL-5 formats:
  • A COMPUTATIONAL-5 data item can be signed; a COMPUTATIONAL-X data item must not be signed. When "x"s are used in the PICTURE clause for a COMP-5 data item, it is treated as unsigned, not signed.
  • A COMPUTATIONAL-X item is always stored using the same storage scheme as BINARY items, that is with the high-order bytes stored at the lowest addresses and successively lower-order bytes at successively higher addresses.

    The storage of COMPUTATIONAL-5 items is operating system-specific. In some operating systems COMPUTATIONAL-5 items are stored in the same format as COMPUTATIONAL-X items and in others they are stored with the low-order bytes stored at the lowest addresses and successively higher-order bytes stored at successively higher addresses. For example, under operating systems which store numeric items in reverse order, a PIC X(5) COMPUTATIONAL-5 item with a numeric internal value of:

    h "12 34 56 78 9A"

    would be stored as:

    9A 78 56 34 12

    while a COMPUTATIONAL-X item (or a COMPUTATIONAL-5 item on an operating system without reverse numeric storage) would be stored as:

    12 34 56 78 9A

  • A COMPUTATIONAL-5 item is affected by the IBMCOMP Compiler directive and possibly the SYNCHRONIZED clause; a COMPUTATIONAL-X item is not.
• If a non-arithmetic statement attempts to store a negative value in a COMPUTATIONAL-X or unsigned COMPUTATIONAL-5 item, the value is stored in two's complement, as if the item had been signed.

  The result of a statement attempting to store a negative value in an unsigned COMPUTATIONAL-5 item is sensitive to the COMP-5 Compiler directive.