$-$Calculate the time necessary to perform a multiply using the approach given in

Figure $3\mathrm{.}7$ if an integer is $16$ bits wide and an adder takes $4$ time units.FIGURE $3\mathrm{.}7$ Fast multiplication hardware. Rather than use a single $32-$bit adder $31$ times, this hardware "unrolls the loop" to use $31$

adders and then organizes them to minimize delay.