Drawing the screen: sync_in

       Name: sync_in                                                 [Show more]
       Type: Subroutine
   Category: Drawing the screen
    Summary: Implement the sync_in command (wait for the vertical sync)
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * tube_table calls sync_in


 This routine is run when the parasite sends a sync_in command. It waits for
 the next vertical sync and returns a value to the parasite so it can wait
 until the sync occurs. The value returned to the parasite isn't important, as
 it's just about the timing of the response.


.sync_in

 JSR WSCAN              \ Call WSCAN to wait for the vertical sync

 JMP tube_put           \ Send A back to the parasite and return from the
                        \ subroutine using a tail call