Question $4-$ Use of the stack $(25$ points$)$

The following code has three different functions, Main, SumFung, and LoddFunc. The

functions do not implement MIPS caller$/$callee conventions. Each function has a

description above it to give you an overview of the function. An example $.$data section is

given at the end of the code section.

The purpose of this question is to evaluate your understanding of stack operations in

MIPS.

Add as many instructions as needed to implement caller$/$callee conventions. Do not put

unnecessary data on the stack. There might be more than one correct answer. Use the

provided callouts to insert your instructions. Some callouts may remain empty.

$.$ text

## main is a test case for the SumFunc internal function.

# In memory, are the value A and the value $B.$

# The compute sum will be stored in memory at Result.

main: la $t$0,$ A #loads address of $A$

la st$1,$ B #loads address of $B$

la $t$3,$ Result #loads address of Result

move $a$0,$ $to #address of $A$ is input to SumFunc

move sal, $t$1$ #address of $B$ input to SumFunc

jal SumFunc #calls SumFune

sw $v$1,0($$t$3)$ #saves sum into Result

##SumFunc takes two inputs

# $($ $$a0-$address of $A,$ $al$-$address of $B)$

# and returns a value in $$v0$

# returned is the sum of the values at those memory locations

SumFunc:

move $$30,$ $a$0$ #moves addr of A into saved register

move $s$1,$ $al #moves addr of $B$ into saved register

move $$a0,$$$s0$ #addr of $A$ is input to lst LoadFunc call

jal LoadFunc #call LoadFunc to get value of $A$

move $$30,$$$v0$ #moves returned value to $$30$

move $a$0,$ $s$1$ #base addr of array is AddressFunc input

jal LoadFunc #call LoadFunc to get value of $B_{{?}_{?}}$

move $$31,$$$v0$ #moves returned value to $$30$

#$($this is now the value of $B)$

add $$s1,$$$s1,$$$s0$ #adds the two values together

move $$v0,$$$31$ #return sum as output of SumFunc

jr Sra # return to main

## AddressFunc takes one input $($ $$a0-$ address of value$)$

# and returns a value in $$v0-$ the value at addr passed in

LoadFunc:

lw $$v0,0($$$a0)$ #loads value of address

ir sra #return to SumFunc