8.9 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 ; in main 0 . 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 $+0 and $t1 are initialized in the simulator as: the results are stored in $t2 and $t3 : Note: Use the ' + ' button under the Registers display to initialize register values for $t0 and $t1