Consider the following portions of two different

programs running at the same time on four processor

Cores in a symmetric multicore processor $($SMP$).$ Assume

that before this code is run, both $x$ and $y$ are $0.$

Core $1$: $x=2$;

Core $2$: $y=2$;

Core $3$: w $=$ x $+$ y;

Core $4$: $z=x-y$;

What are all the possible resulting values of $w,x,y,$ and

z$?$ For each possible outcome, explain how we might

arrive at those values. You will need to examine all

possible interleavings of instructions.