Question

In standard machine language instruction which component identifies the specific operation to be performed such as addition or data movement:

• A. Register
• B. Opcode
• C. Operand
• D. Immediate Address

Hint:

Machine Instruction Format: Opcode + Operand(s) Opcode tells the CPU:

• ADD

• SUB

• MUL

• MOV

• DIV
Operands tell the CPU where the data is located.

Answer 1

The Correct Option is B

Concept: A machine language instruction generally consists of two major parts: \[ \text{Instruction}= \text{Opcode}+\text{Operand} \] where:

• Opcode specifies

what operation must be performed.

• Operand specifies

on which data the operation is performed.

Step 1: Understand the role of Opcode.
Opcode stands for

Operation Code. Examples: \[ ADD \quad SUB \quad MOV \quad MUL \quad DIV \] These instructions tell the CPU exactly what action to perform. For example: \[ ADD\ R1,R2 \] Opcode = ADD Operands = \(R1,R2\)

Step 2: Understand why other options are incorrect.
Register: Stores data temporarily inside CPU. Operand: Represents the data or memory location on which the operation is performed. Immediate Address: Represents a value directly embedded inside the instruction. None of these determine the actual operation.

Step 3: Identify the instruction field responsible for the operation.
The field that tells the processor whether to perform addition, subtraction, movement, multiplication, etc. is the: \[ \boxed{\text{Opcode}} \] Hence option (B) is correct.