Write a program that calculates the following expression, using registers: E = (2*(A - B)) - (4*(C + D)). Assign initial integer values to A, B, C, and D. Store E to the memory location labeled "Result", allocated by .word Assembler Directive. Include the class header at 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. In ARM assembly language.