# Opcodes of 8085 Microprocessor

As we know that the 8085 microprocessor is an 8-bit microprocessor. So, a total of 256 instruction codes can be generated using 8-bit combinations. But out of 256 instruction codes, only 246 instruction codes are defined by INTEL Corporation for 8085 microprocessor. Each defined instruction code performs a unique task. These instruction codes are called operational code or opcode. There are exact 74 basic functions. The size of the 8085 microprocessor instruction code (or opcode) can either be one-byte or two-bytes or three-bytes.

The following table shows the possible combinations of instruction codes from the 8-bit combinations. Each hexadecimal equivalent is mentioned across each instruction code.

 Instruction Code Binary Hexadecimal Code instruction #1 0000 0000 00 H Code instruction #2 0000 0001 01 H

.                                                         .                                                        .

.                                                         .                                                        .

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 Code instruction #255 1111 1110 FE H Code instruction #256 1111 1111 FF H

Let us take an example of instruction codes given by Intel corporation.

MOV A,B

The above instruction has a task to move the data present in register B to the accumulator A. The binary code corresponding to this instruction is 0111 1000 and its opcode is 78 H.

This instruction has a task to add the data present in register C with the accumulator (A) and store the result in the accumulator. The binary code corresponding to this instruction is 10000001 and its opcode is 81 H.

## Opcodes Table of 8085 Microprocessor

Here is the complete list of the instruction set of 8085 microprocessor.

You have seen opcodes of 8085 Microprocessor in the above table.

8 Bit Logical Compare Instructions

8 Bit Logical Rotational Instructions

16 Bit Arithmetic Instructions

16 Bit Data Transfer Instructions

8 Bit Logical Instructions

8 Bit Arithmetic Instructions

Machine Control Instructions

8 Bit Data Transfer Instructions

### 3 thoughts on “Opcodes of 8085 Microprocessor”

1. Please explain the calculation of opcode interms of Hex values