$6.$ Show how to make the shift register of Figure below reverse the order of its

bits $($i$.$e$.,$ Q$3+=$ Q$0,$ Q$2+=$ Q$1,$ Q$1+=$ Q$2,$ and Q$0+=$ Q$3).$

a$.$ Use external connections between the Q outputs and the D inputs.

What should the values of Sh and L be for a reversal?

b$.$ Change the internal circuitry to allow bit reversal, so that the D inputs

may be used for other purposes. Replace Sh and L with A and B$,$ and

let the register operate according to the following table: