From Binary Semaphores to Counting Semaphores

BS1 : binary semaphore = 1;

BS2 : binary semaphore = 0;

Count: integer = initial value of counting semaphore.

• Wait( s )

wait( BS1 ); Count := Count - 1;

if Count < 0

signal (BS1 ); wait( BS2 );

signal ( BS1 );

• Signal ( s )

wait( BS1 ); Count := Count + 1;

if Count ? 0 then signal( BS2 ) else signal( BS1 );

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