NAME
        AddTask -- add a task to the system

   SYNOPSIS
        result = AddTask(task, initialPC, finalPC)
         D0               A1    A2         A3

        aptr addtask(struct task *, aptr, aptr);

   FUNCTION
        Add a task to the system.  A reschedule will be run; the task with
        the highest priority in the system will start to execute (this may
        or may not be the new task).

        Certain fields of the task control block must be initialized and a
        stack allocated prior to calling this function.  The absolute
        smallest stack that is allowable is something in the range of 100
        bytes, but in general the stack size is dependent on what
        subsystems are called. In general 256 bytes is sufficient if only
        Exec is called, and 4K will do if anything in the system is called.
        DO NOT UNDERESTIMATE.  If you use a stack sniffing utility,
        leave a healthy pad above the minimum value.  The system guarantees
        that its stack operations will leave the stack longword aligned.

        This function will temporarily use space from the new task's stack
        for the task's initial set of registers.  This space is allocated
        starting at the SPREG location specified in the task control block
        (not from SPUPPER).  This means that a task's stack may contain
        static data put there prior to its execution.  This is useful for
        providing initialized global variables or some tasks may want to
        use this space for passing the task its initial arguments.

        A task's initial registers are set to zero (except the PC).

        The TC_MEMENTRY field of the task structure may be extended by
        the user to hold additional MemLists (as returned by allocentry()).
        These will be automatically be deallocated at remtask() time.
        If the code you have used to start the task has already added
        something to the MEMENTRY list, simply use addhead to add your
        new MemLists in.  If no initialization has been done, a newlist will
        need to be performed.

   INPUTS
        task  - pointer to the task control block (TCB).  All unset fields
                must be zero.
        initialPC - the initial entry point's address
        finalPC - the finalization code entry point's address.  If zero,
                  the system will use a general finalizer. This pointer is
                  placed on the stack as if it were the outermost return
                  address.

   RESULTS
        For V36, AddTask returns either a NULL or the address of the new
        task.  Old code need not check this.

   WARNING
        Tasks are a low-level building block, and are unable to call
        dos.library, or any system function that might call dos.library.
        See the AmigaDOS createproc() for information on processes.

   SEE ALSO
        remtask(), findtask(), amiga.lib/createtask(), dos/createproc(),
        amiga.lib/newlist()