a) Consider a method train is going to call another method compute. The compute method has two input parameters and three local variables. It also needs to use registers R5, R6, R7 & R8, which are also used by the train method. What steps are necessary within the compute method to protect these registers, to use input parameters and local variables and finally to safely return to the train method?

Note: Assume that a stack is in place and the train method has already pushed the input parameters to stack for the compute method. You are using the 'callee saved' approach.