For this week$$s programming, we will be implementing basic operations on integer values. We have

two source registers $($R$1$ and R$2$ with values x and y$,$ respectively$),$ and another register $($R$4)$ whose

value $($z$)$ dictates which operation should be performed on x and y$.$

First, you must read the value z in register R$4.$ We then look at its value:

$$ if z $>0$: we perform multiplication $($x $$ y$)$;

$$ if z $=0$: we perform addition $($x $+$ y$)$;

$$ if z $<0$: we perform subtraction $($y $$ x$).$

The result of this operation should be stored in register R$3.$ Please note:

$1.$ You do not have to convert the negative values into their decimal notation when doing any of

the operations;

$2.$ For subtraction, make sure that you perform it in the right order on x and y $($so y $$ x$,$ not

x $$ y$)$;

$3.$ For addition, the order does not matter;

$4.$ For multiplication, we also expect that if x $<0$ and y $<0,$ then x $$ y $>0($in other words,

multiplying two negative numbers should yield a positive number$)$

Note that you must make sure that you implement an efficient way of doing multiplication. In assembly lc$3$