can someone help me with the following lc3 problem

"as a systems programmer for the lC3, you are tasked with adding new subroutines for integer input and output. The subroutines will be pre loaded into the LC3 at memory locations x04C0 (input) and x04E0 (output) the subroutines are to be accessible via TRAP x27 (input) and TRAP x28 (output) calls.

How do you accomplish this?

Integer input:

integer output:"

for the answer the question is asking for an integer input as well as output but i have no idea on how to answer it

please help