Solution:

The main job of the Address Generation Unit is to generate the address of the operands required to carry out the operation.

They have to work fast in order to satisfy the timing constraints.

As the address generation unit has to perform some mathematical operations in order to calculate the operand address, it is provided with a separate ALU.

Address generation typically involves one of the following operations.

a. Getting value from an immediate operand, register, or a memory location

b. Incrementing/ decrementing the current address

c. Adding/subtracting the offset from the current address

d. Adding/subtracting the offset from the current address and generating a new address according to circular addressing mode

e. Generating new address using bit reversed addressing mode

The block diagram of a typical address generation unit is shown in the figure.