How to compare two internal table data and it's field(like the diff in debug)

Dear expert,

         I want to create an report which can compare the internal table data and it's field(like the diff in debug).

         It can compare it's filed and show us the different field such as:

          If the two table have the same structure, then it can show us the different of the data :

I know there are one FP: SAPLSTPDA_TOOL_DIFF, but I want to know how this program process, how to realize this.

Thanks for your sincerely answer.