NAME
        InitSemaphore -- initialize a signal semaphore

   SYNOPSIS
        InitSemaphore(signalSemaphore)
                      A0

        void InitSemaphore(struct signalsemaphore *);

   FUNCTION
        This function initializes a signal semaphore and prepares it for
        use.  It does not allocate anything, but does initialize list
        pointers and the semaphore counters.

        Semaphores are often used to protect critical data structures
        or hardware that can only be accessed by one task at a time.
        After initialization, the address of the signalsemaphore may be
        made available to any number of tasks.  Typically a task will
        try to obtainsemaphore(), passing this address in.  if no other
        task owns the semaphore, then the call will lock and return
        quickly.  If more tasks try to obtainsemaphore(), they will
        be put to sleep.  When the owner of the semaphore releases
        it, the next waiter in turn will be woken up.

        Semaphores are often preferable to the old-style forbid()/permit()
        type arbitration.  With forbid()/permit() *all* other tasks are
        prevented from running.  With semaphores, only those tasks that
        need access to whatever the semaphore protects are subject
        to waiting.

   INPUT
        signalSemaphore -- a signal semaphore structure (with all fields
                           set to zero before the call)

   SEE ALSO
        obtainsemaphore(), obtainsemaphoreshared(), attemptsemaphore(),
        releasesemaphore(), procure(), vacate(), exec/semaphores.h