9. Hardware solutions to the critical section problem use read-modify-write instructions: these instructions are indivisible because the CPU gets to hold onto the memory bus for two cycles, to both read and then update the shared memory location. As an ex- ample, hereis codeforimplementingmutual exclusion usingaSwap()machine-code instruction; that instruction has the opcode EXCH in the Pentium instruction set. Each process Piexecutes the same code to access its critical section, where key is a boolean localvariable and lockis a shared memorylocation among processes Pithat contains a boolean value, initially set to false. Process Pi: do { key = true; while (key == true) Swap(& lock, & key); ... Critical section of Pi... lock = false } while(true); Describe what happens if three processes try to enter their critical section at about the same time. How does the given code ensure that only one process gets entry