The DAA (Decimal Adjust Accumulator) instruction is a specialized arithmetic command in the 8085 microprocessor designed to facilitate Binary Coded Decimal (BCD) arithmetic. While the 8085's Arithmetic Logic Unit (ALU) natively performs binary addition, most human-facing systems—like calculators or digital clocks—require results in base-10. The DAA instruction bridges this gap by automatically correcting binary results into valid packed BCD format, where each 8-bit byte represents two decimal digits (00 to 99).
The between DAA in the 8085 versus the 8086 or Z80. Daa Instruction In 8085 Microprocessor
An example showing how to add two large decimal numbers. The DAA (Decimal Adjust Accumulator) instruction is a