A Barrel Shifter is a special hardware unit in ARM processors that performs bit-wise shift and rotate operations on one of the operands before it enters the ALU.
This shifting is done within the same instruction cycle, making it a very powerful and efficient feature of the ARM instruction set.
Why is the Barrel Shifter Useful?
- Used to perform quick multiplication/division by powers of 2.
- Helps in bit-field manipulation and efficient constant loading.
- Increases the flexibility of data processing instructions without needing extra instructions.
Where is it Used?
In data processing instructions, like:
ADD, SUB, MOV, CMP, AND, ORR, EOR, etc.
The second operand (called Operand2) is passed through the barrel shifter.
Data Flow Diagram
