What are the different types of fields that are part of an instruction?

What are the different types of fields that are part of an instruction. Explain.

An instruction can be considered to be a command that has been issued to a computer to perform a particular operation. The instruction format contains various field in them such as:

- Operation Code Field: Also known as the op code field, this field is used to specify the operation to be performed for the instruction.

- Address Field: This field as its name specifies is used to designate the various addresses such as register address and memory address.

- Mode field: This field specifies as to how effective address is derives or how an operand is to perform.

- For ex. ADD R0, R1. In this case the ADD is the operand whereas the R1, ans R0 are the address fields.