How is Comp-3 stored?

COMP-3 data stored in memory higher to lower in the size of nibble (4 bits). i.e. The upper nibble stores the most significant digit and lower nibble stores the next digit and the upper nibble stores the next digit etc.

What is Comp and Comp-3?

Comp is a binary usage, while comp-3 indicates packed decimal. The other common usages are binary and display. IBM Mainframes are typically binary and AS400’s are packed. ‘

How many bytes is a Comp-3 field?

To calculate the byte-length of a comp-3 field, start with the total number of digits and divide by 2 giving a result (discarding the remainder if any), then add 1 to the result. So, a field with “pic s9(6) comp-3” would take 4 bytes (6/2 +1).

What is the maximum length of a field you can define using COMP-3?

18 decimal digits
The maximum length of a computational item is 18 decimal digits, except for a PACKED-DECIMAL item.

What is a packed field?

Introduction. This document will focus on a discussion of a numeric field (or data string) known as “PACKED-DECIMAL” format (also referred to as packed data or a packed numeric field). A packed decimal representation stores two decimal digits in one byte.

What is Comp-3 variable in mainframe?

COBOL Comp-3 is a binary field type that puts (“packs”) two digits into each byte, using a notation called Binary Coded Decimal, or BCD. This halves the storage requirements compared to a character, or COBOL “display”, field. (See COBOL Computational Fields for information on the comp data type).

What is Comp-3 variables COBOL?

COBOL Comp-3 is a binary field type that puts (“packs”) two digits into each byte, using a notation called Binary Coded Decimal, or BCD. This halves the storage requirements compared to a character, or COBOL “display”, field.

What is Comp 4 COBOL?

BINARY data and synonyms COMP and COMP-4 are the two’s complement data representation in COBOL. The compiler option TRUNC(OPT | STD | BIN) determines if and how the compiler corrects values back to the declared picture clause and how much significant data is present when accessing a data item. …

Can we display Comp-3 variables COBOL?

In the below file, the last 2 Bytes are COMP-3 Data. You read the Hexa-decimal value in a top-down fashion. 3. You may also DISPLAY this in COBOL, by first MOVE’ing the data to a Numeric-Edited DISPLAY Format Variable.

Can Comp-3 be converted to numeric?

You cannot move a COMP-3 variable to alphanumeric directly. It will not give a SOC7 error but will you give you a return code 12 stating that comp-3 and alphanumeric variables did not follow the move compatibility rule. 01 A1 PIC S9(4) COMP-3 VALUE 1234.

Can we move alphanumeric to comp-3?

In comp-3 data representation is in packed decimal and in alphanum data is stored in ascii form so bcuz of data incompatibility Alphanumeric to COMP-3 data movement is not possible.

What is a Comp field in COBOL?

COBOL has what you might call “decimal-binary” fields (COMP and siblings). That is, the data is stored as binary but its maximum and minimum values are the number and full value of the PICture clause which is used in the definition. COMP PIC 9 – can contain zero to nine. COMP PIC S99 – (signed) can contain -99 to +99.

How is the value stored in a comp-3 field?

The value in a comp-3 field is stored high-order to low-order. That is, the upper nybble of the first byte encountered in the file is the most significant digit of the value, the lower nybble of that byte is the next digit, etc., etc.

What happens when you unpack a comp-3 field?

When you “unpack” a packed, or comp-3, field, the size of the field will double. This will cause all fields following it to shift down.

How are comp-3 packed fields aligned on byte boundaries?

Comp-3 packed fields are aligned on byte boundaries, and the field is always a whole number of bytes. The sign nybble is always the low nybble of the LSD (least significant digit). Since the sign takes one nybble, and because there are always an even number of nybbles in any number of bytes, an odd number of digits will fully-fill a comp-3 field.

Which is the most common format for comp-3 fields?

Although comp-3 is “vendor specific”, the format of comp-3 fields is almost universal across platforms, even on ASCII machines. Comp-3 stores data in a BCD — binary coded decimal — format with the sign after the least significant digit. Comp-3 is so common that we have written a separate Tech Talk brief about it.