Write in Assembly, comment code please

Write a program that calculates the following expression, using registers: A = (2* (A + B)) - (3*(C-D)). Assign initial integer values to A, B, C and D. Note that A will be changed by reassigning the resulting calculation to A. Store A to the memory location labeled "Result", allocated by by.word. Include the class header in the beginning of the code. Verify results by using the debugger. Comment your program. Specifically, identify all variables (registers) used with a synopsis of their purpose in the program