What is Comp and Comp-3?

COMP usage stores the data in half word or in full word, depending on the size of the data. COMP3 usage stores 1 digit in half byte (i.e. 4 bits) and a separate 1 bit is reserved for the sign, which is stored at the right side of the data.

What is the use of comp-3 in 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.

How is Comp-3 calculated?

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).

How many bytes Comp-3 will take?

COMP-3, being Binary Coded Decimal, takes 1/2 byte per digit. So take the picture size, divide by two, and round up.

Why do we use comp-3?

COMP-3 enables the computer to store two digits in each storage position, except for the rightmost position, which holds the sign. Suppose if you move 1234567 into a field defined 9(7). In DISPLAY mode, which is default, this field will use 7 storage positions.

What is Comp-3 variable in mainframe?

COMP-3 is the equivalent of PACKED-DECIMAL. COMP-3 usage clause is applicable for numeric data type. If an item declared as COMP-3, the item appears in storage in packed decimal format. The right most half byte contains the sign value. COMP-3 data item contains any of the digits 0 through 9, a sign.

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.

Which is faster COMP or COMP-3?

Comp-3 = Packed-Decimal is faster, because the z/Architecture, and also previous architectureres beginning with S/360, has built in instructions to directly manipulate Packed-Decimal data, e.g AP (Add packed).

Can we move Comp to Comp-3?

1. it possible to move a comp-3 field to a comp field or display field and vice versa.. 2. it possible to redefine a field with comp-3 status to a comp status.

Why comp is used 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.

What is Comp 4 COBOL?

comp-4 Data comp-4 is fixed-point binary data with 15-bit precision, word-aligned, and stored in two bytes. The scaling factor is zero. Values are stored in two’s complement form. For integer data, such as counters and switches that do not require values outside the range -32,768 to +32,767, use comp-4 data.

How many bytes is a comp 5?

COMPUTATIONAL-5 or COMP-5 (native binary) The data items can contain values up to the capacity of the native binary representation (2, 4, or 8 bytes), rather than being limited to the value implied by the number of nines in the picture for the item (as is the case for USAGE BINARY data).

What is comp in mainframe?

COMP usage is a binary representation of data and stores in pure binary format. The amount of storage occupied by a binary item depends on the number of decimal digits defined in its PICTURE clause.

What is the difference between COMP 1 and COMP 2?

COMP-1 refers to short (single-precision) floating-point format, and COMP-2 refers to long (double-precision) floating-point format, which occupy 4 and 8 bytes of storage, respectively. The leftmost bit contains the sign; the next seven bits contain the exponent; the remaining 3 or 7 bytes contain the mantissa.

What is comp-3 example?

COMP-3 Example : +87634 will be displayed as 864 73C -4567 will be displayed as 057 46D last characters represents sign. if last character is C or F, that denotes a positive sign. If last character is D , that denotes a negative sign.

How is the sign represented in Comp 3?

COMP-3:In this case the data is represented in the decimal form, but one digit takes half a byte. The sign is stored separately as the rightmost half a byte character.

What is the full form of comp-1?

COMPUTATIONAL-1 or COMP-1 Specified for internal floating-point items (single precision). COMP-1 items are 4 bytes long. The sign is contained in the first bit

What is the size of a comp-3 byte?

PIC 9 (7) COMP-3. Byte size = (7 + 1) / 2 = 4 PIC 9 (6) COMP-3. Byte size = (6 + 1) / 2 = 3.5, rounded to 4 Lets look at some examples of how comp-3 data is stored.

https://www.youtube.com/c/COMP3Interactive