4. (10 points) Synchronization The test and set() instruction and its usage are given in the code below. Explain in a few sentences how the test and set() instruction provides mutual exclusion for the critical section problem below. boolean test and set (boolean *target) { boolean rv - *target; *target - true; return rv; do while (test and set (&lock)) ; /* do nothing */ /*critical section */ lock-false; /remainder section / while (true); 4. (10 points) Synchronization The test and set() instruction and its usage are given in the code below. Explain in a few sentences how the test and set() instruction provides mutual exclusion for the critical section problem below. boolean test and set (boolean *target) { boolean rv - *target; *target - true; return rv; do while (test and set (&lock)) ; /* do nothing */ /*critical section */ lock-false; /remainder section / while (true)