(a) add the 16-bit values stored in data memory at 0x2010~0x2011 and 0x2040~0x41 and leave the sum in registers r16~r17 (high byte in r17). (b) subtract the 16-bit value stored in program memory at 0x1080~0x1081 from r16~r17 and save the difference in data memory locations 0x$2090~0x2091.

this class has been on the atxmega128a1u microctontroller