E1.18 Write an instruction sequence to swap the 16-bit word stored at $1000-$1001 with the 16-bit word stored at $1100-$1101. E1.19 Give an instruction that can store the contents of accumulator D at the memory location with an address larger than the contents of X by 8. E1.20 Give an instruction that can store the contents of index register Y at the memory loca- tion with an address smaller than the contents of X by 10