Some computers whose words are multiples of an octet (8-bit byte), for example contemporary IBM mainframe systems, support packed BCD (or packed decimal [38]) numeric representations, in which each nibble represents either a decimal digit or a sign.

Oct 29, 2010 · Packed BCD (Binary Coded Decimal) is a numeric format that was directly supported on cpu's almost from the beginning, and still is today. Simply put, it relies on the fact that 4 bits are more than sufficient to represent decimal numbers.

Sep 28, 2023 · Packed BCD: A byte (packed) representation of two decimal digits, each in the range 0 through 9. One digit is stored in each half-byte. The digit in the high-order half-byte is the most...

Mar 27, 2025 · In Packed BCD, each 4-bit nibble of a byte represents one decimal digit. Packed BCD saves memory space compared to other methods, as it uses one byte to store two digits, making it efficient for storage and processing in digital systems.

The use of a single byte (8-bits) to store or display two BCD digits, allowing a byte to hold a BCD number in the range of 00 – 99, is known as packed BCD.

Jul 7, 2023 · In “packed BCD,” two four-bit BCD digits are packed into one byte. In “unpacked BCD,” however, one byte holds only one digit, such that you could use more than four bits per digit without consuming additional memory.

What is the difference between unpacked BCD and packed BCD? Unpacked BCD uses one byte (eight bits) to represent each decimal digit, while packed BCD uses four bits to represent each decimal digit. Packed BCD is more space-efficient but requires additional processing to convert to and from unpacked BCD.

Generally there are 2 types of BCD: unpacked and packed. Unpacked BCD: In the case of unpacked BCD numbers, each four-bit BCD group corresponding to a decimal digit is stored in a separate register inside the machine.

Jan 12, 2024 · What is the difference between Packed BCD and Unpacked BCD? · Packed BCD uses four bits to represent each decimal digit. It is more space-efficient but requires additional processing time than unpacked BCD number. · In an 8-bit register, lower 4 bits are used to store the BCD number, and upper 4 bits are used to store zeros.

A widely used variation of the two-digits-per-byte encoding is called packed BCD (or simply packed decimal), where numbers are stored with two decimal digits "packed" into one byte each, and the last digit (or nibble) is used as a sign indicator.