Instruction type ADI d8 in 8085 Microprocessor

Microprocessor8085

In 8085 Instruction set, ADI is a mnemonic, which stands for “ADd Immediate to Accumulator” and here “d8” stands for any 8-bit or 1-Byte of data. This instruction is used to add 8-bit immediate data to the Accumulator. The result of addition will be stored in the Accumulator. So the previous content of the Accumulator will be over written. It occupies 2-Bytes in memory. The flags are affected based on the result.

Mnemonics, Operand Opcode(in HEX) Bytes
ADI Data C6 2

Let us consider as example instruction ADI 03H of this type. As it is a 2-Byte instruction so it will occupy 2-Bytes of memory locations as well.We are considering that Accumulator is having its initial content of 02H. So after addition the final sum of 05H will be stored on to the Accumulator as well. The result of execution of this instruction is shown below with an example.

Before After
(A) 02H 05H
Flag Register (F) Any values CY=0,AC=0,S=0,P=1,Z=0

Address Hex Codes Mnemonic Comment
2002 C6 ADI 03H Accumulator = Accumulator + Operand 03H
2003 03 Data operand 03H

The timing diagram of this instruction ADI 03H will be as follows −

ADI

Summary − So this instruction ADI 03H requires 2-Bytes, 2-Machine Cycles (Opcode Fetch, Memory Read) and 7 T-States for execution as shown in the timing diagram.

raja
Published on 30-Nov-2018 12:37:25
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