If the initial register contents of R0, R1 and R2 were; R0= 0x00000000 , R1= 0x02040608 , R2= 0x10305070 . Assume R0 is the result register, after one of the operations below was performed on R1 and R2, which has been modified to R0 = 0x12345678 What was the operation performed on the contents of R2 and R1?