A synchronization mechanism consists of 2atomic routines, ENQ(r) and DEQ(r). \"r

Question

A synchronization mechanism consists of 2atomic routines, ENQ(r) and DEQ(r). "r" is a resource variable that has two fields, inuse (boolean) and queue (a queue) which is a queue of processes waiting to acquire the resource. The definitions of ENQ and DEQ are: ENQ(r): if (r.inuse == 1) then begin insert current process in r.queue block end else r.inuse 1; DEQ(r): if r.queue == nil then inuse = false else delete a process from r.queue and activate it. Construct an implementation of ENQ/DEQ using semaphores. You can use other variables, etc that you need, but no other atomic code or synchronization constructs other than P or V can be used. Do the reverse of Q3, that is implement Semaphores using ENQ/DEQ.

Explanation / Answer

Enqueue(p, item)   

{

Acquire(mutex);

put item into p;

Release(mutex);

}

DEQ

Dequeue(q)

{

Acquire(mutex);

take an item from p;

Release(mutex);

return item;

}

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