Briefly explain the differences between the following pairs of con$-$

cepts:

$($i$)$ Compiler vs$.$ Interpreter $(2)$

$($ii$)$ Single$-$pass vs$.$ Multi$-$pass compiler $(2)$

$($iii$)$ Local vs$.$ Global Code Optimisation $(2)$

$($iv$)$ Stack vs$.$ Heap storage $($in memory organisation$)(2)$

$($b$)$ You are given a function myfun$($int a$)$ which takes one $($integer$)$

parameter a$.$ A call x :$=$ myfun$(3+2)$ is made where x is stored

in register $s$0.$

$($i$)$ Describe how the above function call is made when arguments

are passed using stack$-$based parameter passing. $(4)$

$($ii$)$ Describe how the above function call is made when arguments

are passed using register$-$based parameter passing in the MIPS

architecture. $(4)$

$($c$)$ You are performing register allocation on a program, and from live$-$

ness analysis the following interference graph is created:

a b

c d

Assume we have $3$ free registers to use. Explain how to allocate

registers by graph colouring and use graph colouring to give a valid

allocation of a$,$ b$,$ c and d to registers $s$1,$ $s$2$ and $s$3.$ Explain what

will happen if you try graph colouring with only $2$ registers.