NAME
        AllocTrap -- allocate a processor trap vector

   SYNOPSIS
        trapNum = AllocTrap(trapNum)
        D0                  D0

        long alloctrap(long);

   FUNCTION
        allocate a trap number from the current task's pool.  these trap
        numbers are those associated with the 68000 TRAP type instructions.
        Either a particular number, or the next free number may be
        allocated.

        If the trap is already in use (or no free traps are available) a -1
        is returned.

        This function only affects the currently running task.

        Traps are sent to the trap handler pointed at by tc_TrapCode.
        Unless changed by user code, this points to a standard trap
        handler.  The stack frame of the exception handler will be:

                0(SP) = Exception vector number.  This will be in the
                        range of 32 to 47 (corresponding to the
                        Trap #1...Trap #15 instructions).
                4(SP) = 68000/68010/68020/68030, etc. exception frame

        tc_TrapData is not used.


   WARNING
        Traps may not be allocated or freed from exception handling code.
        You are not allowed to write to the exception table yourself.  In
        fact, on some machines you will have trouble finding it - the VBR
        register may be used to remap its location.

   INPUTS
        trapNum - the desired trap number {of 0..15} or -1
                  for no preference.

   RESULTS
        trapNum - the trap number allocated {of 0..15}.  If no traps are
                  available, this function returns -1.  Instructions of the
                  form "Trap #trapNum" will be sent to the task's trap
                  handler.

   SEE ALSO
        freetrap()