DA

The DA instruction adjusts the 8-bit value in the accumulator to correspond to binary-coded decimal (BCD) format. This instruction begins by testing the low-order nibble of the accumulator. If the AC flag is set or if the low 4 bits of the accumulator exceed a value of 9, the accumulator is incremented by 6. The high-order nibble is then tested. If the carry flag is set or if the high 4 bits of the accumulator exceed a value of 9, the value 60h is added to the accumulator. This instruction performs a decimal conversion by adding 00h, 06h, or 66h to the accumulator depending on the initial contents of the PSW and accumulator.

DA

IF (A3-0 > 9) OR (AC = 1)
  A = A + 6

IF (A7-4 > 9) OR (C = 1)
  A = A + 60h

DA A