Three address code:

func begin fact

if n == 0 got L1

t1 = n-1

param t1 // first parameter required to call recursion

refparam result // another parameter which might not seem in function call but define as reference

call (fact, 2) // (name of function, no.of parameters) , 2 because of addition return parameter

t2 = n * result

return t2

L1: return 1

func end