Q. Define Opcode and Operands?

The most common fields which are found in instruction formats are:

Opcode: (What operation to perform?) 

• An operation code field called opcode that specifies operation to be performed.

Operands: (Where are the operands?)

• An address field of operand on that data processing is to be performed.
• An operand can reside in the memory or a processor register or can be combined within the operand field of instruction as an immediate constant. Thus a mode field is requiredwhich specifies the way the operand or its address is to be determined.