2. What is the value of x19 just after the load upper immediate instruction "lui x19, 1" is executed? 3. A tread executes a load reserve doubleword instruction (Ir.d) on memory location D. Later, when the thread executes a store conditional doubleword instruction (sc.d) on D, the store conditional failed. What could have happened? 4. Why can't the output of a circuit be used exactly when an input to the circuit changes? A combinational circuit has one output that is currently 0. When one of the circuit's inputs is changed (say from 1 to 0), the output becomes 1 and then 0. The output should have stayed at 0, but instead changed to 1 and then back to 0. (SA) How could this happen? (SB). The circuit is said to have something. Name the something