What is ALU 

ALU stands for the Arithmetic logic unit and it is an internal part of the processor which is used for all the mathematical and logical operations.  The operations of the ALU includes multiplying the binary values and performing the logical operations such as AND, OR and XOR, integer arithmetic operations and Bit-shifting operations etc.  ALU is the fundamental building block of the processor.

Today, modern computers contain very complex ALU for performing the complex calculations and logical operations inside the computer.  The data or the operands are the input of the ALU and it generates the output as the result of the computation.  In some of the computers the ALU is divided into two units Arithmetic unit and the Logic unit.

Some processors have multiple AU some for the fixed point operations and some of the floating point operations.  In the computers, the ALU has the direct access to the processor’s controller, RAM and the input/output devices.  The output of the ALU is placed inside a storage register.  The design of the ALU is very critical as it is related with the processor’s performance.  Its design can speed up the instructions handling.