Classification of Instruction Formats - 3 Address, 2 Address, 1 Address, 0 Address Instructions

[Computer Organization]
The video explains how the Instruction Formats are classified on the basis of operands:
On the basis of number of operands:
1) 3 Address Instruction
2) 2 Address Instruction
3) 1 Address Instruction
4) 0 Address Instruction

On the basis of location of operands:
1) Memory Reference Instructions
2) Register Reference Instructions
3) I/O Instructions