give step by step on how to solve problem please

Exercises .s a. What does the following program do? ORIG x3000 LD LD LD BRz ADD ADD BR R2, ZERO RO, M0 R1, Mi DONE R2, R2, RO R1, R1, -1 LOOP R2, RESULT LOOP DONEST HALT RESULT FILL x0000 ZERO MO M1 FILL x0000 FILL x0004 . FILL x0803 END b. What value will be contained in RESULT after the program runs to completion