S3F84B8_UM_REV 1.00 6 INSTRUCTION SET6-336.3.21 DA — DECIMAL ADJUST (CONTINUED)DAExample: Given that working register R0 contains the value 15 (BCD), working register R1 containsthe value 27 (BCD), and address 27H contains the value 46 (BCD):ADD R1,R0 ; C “0”, H “0”, Bits 4–7 = 3, bits 0–3 = C, R1 3CHDA R1 ; R1 3CH + 06If addition is performed using the BCD values 15 and 27, the result should be 42. The sum isincorrect, however, when the binary representations are added in the destination location usingstandard binary arithmetic:0 0 0 1 0 1 0 1 15+ 0 0 1 0 0 1 1 1 270 0 1 1 1 1 0 0 = 3CHThe DA instruction adjusts this result, so that the correct BCD representation is obtained:0 0 1 1 1 1 0 0+ 0 0 0 0 0 1 1 00 1 0 0 0 0 1 0 = 42Assuming the same values given above, the statementsSUB 27H,R0 ; C “0”, H “0”, Bits 4–7 = 3, bits 0–3 = 1DA @R1 ; @R1 31–0leave the value 31 (BCD) in address 27H (@R1).
