Instruction type INX SP in 8085 Microprocessor


In 8085 Instruction set, INX SP instruction is used to increment the SP contents by 1. INX SP instruction is a special case of INX rp instruction which increases the content of the register pair. This instruction occupies only 1-Byte in memory.

Mnemonics, Operand Opcode(in HEX) Bytes
INX SP 33 1

Let us consider that the initial content of SP is 4050H. So after increment of the content of SP by using INX SP instruction, SP would have the value 4051H. Here is the required tracing table as below −

Before After


4050H 4051H

Address Hex Codes Mnemonic Comment
2003 33 INX SP SP ←SP + 1

The timing diagram against this instruction INX SP execution is as follows −


Summary − So this instruction INX SP requires 1-Byte, 1-Machine Cycle (Opcode Fetch) and 6 T-States for execution as shown in the timing diagram.

Published on 05-Dec-2018 10:47:12