a)What is a scratch pad memory? Explain the organization of a processor unit using scratch pad memory with the help of neat diagram. b) Design an arithmetic circuit with two selection variables S and So that generates the following arithmetic operation as shown in figure 1 .Draw the logic diagram of one typical stage. C.-! S, C=0 S. 0 0 F- F+1+1 0 1 F=A-B F = A -B-1 Figure 1 F =B-1-1 F-B-A 1 F = A +B F=A+B+! 1 0