NAME
       WaitTOF -- wait for the top of the next video frame.

   SYNOPSIS
       WaitTOF()

        void WaitTOF( void );

   FUNCTION
       wait  for vertical blank to occur and all vertical blank
       interrupt routines to complete before returning to caller.

   INPUTS
       none

   RESULT
        Places this task on the TOF wait queue. When the vertical blank
        interrupt comes around, the interrupt service routine will fire off
        signals to all the tasks doing WaitTOF. The highest priority task
        ready will get to run then.

   BUGS

   SEE ALSO
        exec.library/wait() exec.library/signal()