Semaphore Class Reference

#include <synch.h>

List of all members.

Public Member Functions
	Semaphore (char *debugName, int initialValue)
	~Semaphore ()
char *	getName ()
void	P ()
void	V ()

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Constructor & Destructor Documentation

Semaphore::Semaphore (  char *  debugName, int  initialValue )

Definition at line 36 of file synch.cc. { name = debugName; value = initialValue; queue = new List; }

Semaphore::~Semaphore (   )

Definition at line 49 of file synch.cc. { delete queue; }

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Member Function Documentation

char* Semaphore::getName (   )  [inline]

Definition at line 43 of file synch.h. { return name;} // debugging assist

void Semaphore::P (   )

Definition at line 64 of file synch.cc. References List::Append(), currentThread, DEBUG(), Thread::getName(), interrupt, IntOff, IntStatus, Interrupt::SetLevel(), and Thread::Suspend(). Referenced by Ping(), and Pong(). { IntStatus oldLevel = interrupt->SetLevel(IntOff); // disable interrupts while (value == 0) { // semaphore not available queue->Append((void *)currentThread); // so go to sleep DEBUG('t', "Suspendp %s\n", currentThread->getName()); currentThread->Suspend(); } value--; // semaphore available, // consume its value (void) interrupt->SetLevel(oldLevel); // re-enable interrupts }

void Semaphore::V (   )

Definition at line 88 of file synch.cc. References DEBUG(), Thread::getName(), interrupt, IntOff, IntStatus, Scheduler::ReadyToRun(), List::Remove(), scheduler, and Interrupt::SetLevel(). Referenced by Ping(), and Pong(). { Thread *thread; IntStatus oldLevel = interrupt->SetLevel(IntOff); thread = (Thread *)queue->Remove(); if (thread != NULL) // make thread ready, consuming the V immediately { scheduler->ReadyToRun(thread); DEBUG('t', "Wakeup %s\n", thread->getName()); } value++; (void) interrupt->SetLevel(oldLevel); }

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The documentation for this class was generated from the following files:

• synch.h
• synch.cc

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