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Arithmetic Group Instructions (Part-V)

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INR R:
  • This instruction increments the contents of specified register by 1.
  • The result is stored in the same register.
  • Register R can be any general purpose register like A, B, C, D, E, H and L.
  • All flags are modified except carry flag.
  • It is a one byte instruction.
  • Register addressing mode is used.
Example:
If B = 50H
INR B ; This instruction increments the contents of B (50H) by one and the result (51H) is stored in B.

INR M:
  • This instruction increments the contents of the memory location pointed by HL register pair by 1.
  • The result is stored in the same memory location.
  • All flags are modified except carry flag.
  • It is a one byte instruction.
  • Register indirect addressing mode is used.
Example:
If HL = 1000H and (1000H) = 20H
INR M ; This instruction increments the contents of location 1000H i.e. 20H by one and the result (21H) is stored in location 1000H.

INX Rp:
  • This instruction increments the contents of the specified register pair by 1.
  • The result is stored in the same register pair.
  • Rp is 16-bit register pair like BC, DE, HL or SP.
  • Only higher order register is specified for register pair.
  • No flags are modified.
  • It is a one byte instruction.
  • Register addressing mode is used.
Example:
If HL = 2000H
INX H ; This instruction increments the contents of HL register pair (2000H) by one and the result (2001H) is stored in HL.
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