INR, INX, DCR, DCX, DAA instruction

11. INR: - The contents of the designated register or memory) are incremented by 1 and the result is stored in the same place. If the operand is a memory location, its location is specified by the contents of the HL registers.

Eg: -INR B( the content of register B is incremented by 1.

       INR M( the content of memory location pointed by HL pair in incremented by 1)

12. INX: - Increment register pair by 1.

Eg: INX H (It means the location pointed by the HL pair is incremented by 1)

13.DCR: - The contents of the designated register or memory are M decremented by 1 and the
result is stored in the same place. If the operand is a memory location, its location is specified by the contents of the HL registers.

Eg: - DCR B(content of register B is decremented by 1)

         DCR M(the content of memory location pointed by the HL pointer is decremented by 1.)

14. DCX: - decrement the register pair by 1.

Eg: DCX H( it decreases the memory location pointed by HL pair by 1.

15. DAA: - Decimal adjust accumulator.

The contents of the accumulator are changed from a binary value to two 4-bit binary coded decimal (BCD) digits. This is the only instruction that uses the auxiliary flag to perform the binary to BCD conversion, and the
conversion procedure is described below. S, Z, AC, P, CY flags are altered to reflect the results of the operation.

If the value of the low-order 4-bits in the accumulator is greater than 9 or if AC flag is set, the instruction adds 6 to the low-order four bits. If the value of the high-order 4-bits in the accumulator is greater than 9 or if the Carry flag is set, the instruction adds 6 to the high-order four bits.