Q$5.$ The basic function performed by a computer is execution of a program. A program consists of set of instructions. These

instructions are stored in memory in sequential order. The processor reads instructions from memory one at a time and executes

them. Consider a hypothetical machine $($representing modern computer$)$ which consists of

$-$Program Counter $($PC$)$: A register which contains the address of the memory where the next instruction that is to be executed. This

register can store $8-$bit address.

$-$Register file: This contains three registers, R$1,$ R$2,$ and R$3$ each capable of storing $8-$bit data.

Memory: $256$ X$8$ bits.

Sample instructions are:

i$)$AND R$1,$ R$1,$ #$0//$ Clears the register

ii$)$MUL R$1,$ R$2,$ R$3//$ Multiplies the contents of R$2$ and R$3$ and stores the result in R$1$

Answer the following questions:

a$)$ Draw the best hardware implementation for realizing the instruction AND R$1,$ R$1,$ #$0[1$ mark$]$

b$)$ Consider the instruction MUL R$1,$ R$2,$ R$3.$ What should be the maximum and minimum values of R$2$ and R$3$ to obtain correct

output in R$1.[2$ Marks$]$

c$)$Draw the best hardware implementation for realizing the instruction MUL R$1,$ R$2,$ R$3[3$ marks$]$

d$)$ What is the addressability and address space of the given memory. $[2$ Marks$]$

e$)$ Draw the block diagram for implementing $256$X$8$ bits memory. Show all necessary inputs, outputs and control signals. $[3$ Marks$]$