Consider the following instruction mix:

R$-$type I$-$Type LDUR STUR CBZ B

$24\%28\%25\%10\%11\%2\%$

$4\mathrm{.}3\mathrm{.}1[5]<4\mathrm{.}4>$ What fraction of all instructions use data memory?

$4\mathrm{.}3\mathrm{.}2[5]<4\mathrm{.}4>$ What fraction of all instructions use instruction memory?

$4\mathrm{.}3\mathrm{.}3[5]<4\mathrm{.}4>$ What fraction of all instructions use the sign extend?

$4\mathrm{.}3\mathrm{.}4[5]<4\mathrm{.}4>$ What is the sign extend doing during cycles in which its output

is not needed?