Write a program in assembly that reads a group of unsigned $8-$bit numbers stored in Program ROM starting from location $123$F$2$H and store their sum in RAM registers $200$H $($SUM$\_$L$)$ and $201$H $($SUM$\_$H$)$

Note: the numbers are less than $255$ and the last number is $-1,$ so your program should keep reading numbers until it reads the number $-1.$