Instruction Format of 8085

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.