The 8085 has 74 basic instructions and 246 total instructions. The instruction set of 8085 is defined by the manufacturer INTEL Corporation. Each instruction of 8085 has a one-byte opcode. With 8-bit binary code, we can generate 256 different binary codes. In this, 246 codes have been used for opcodes of 8085 instructions.
The size of 8085 instruction can be one-byte, two bytes, or three bytes. The one-byte instruction has an opcode alone and the two-byte instruction has an opcode followed by an eight-bit address or data. The three-byte instruction has an opcode followed by a 16-bit address or data. While storing the three-byte instruction in memory, the sequence of storage is, opcode first followed by a low byte of address or data and then a high byte of address or data. The format of 8085 instructions is shown in the figure.