$8\mathrm{.}10$ LAB: Function calls

Given the following C program and the mapping of registers to variables, complete the MIPSzy implementation of Main. Do not implement return $0$ ; in main$().$

$```$

int Dif$($int a$,$ int b$)\{$

return a $-$ b;

$\}$

int Sum$($int a$,$ int b$)\{$

return a $+$ b;

$\}$

int main$()\{$

int x$,$ y;

w $=$ Sum$($x$,$ y$)$;

z $=$ Dif$($y$,$ x$)$;

return $0$; $//$ Do not implement

$\}$

$```$

Hints: Use program stack to pass arguments, return values, and preserve saved registers. Remember to pop the stack after each function returns.

Ex: If the values of $\backslash (\backslash$$ $\backslash )$ t$0$ and $\backslash (\backslash$$ $\backslash$mathrm$\{$t$\}1\backslash )$ are initialized in the simulator as: the results are stored in $\backslash (\backslash$$ $\backslash$mathrm$\{$t$\}2\backslash )$ and $\backslash (\backslash$$ $\backslash$mathrm$\{$t$\}3\backslash )$ :

Note: Use the $\text{'}+\text{'}$ button under the Registers display to initialize register values for $\backslash$$t$0$ and $\backslash$$t$1.$

RUN