-; To make a request for swapping the display buffers call tgi_ioctl(4, dataptr)
-; If the value of the char pointed to by the dataptr is 0 then fill in the
-; value of the char with the current state of the swap buffer 0 = idle, 1 = busy
-; If the value is not 0 then activate the swap function at next VBL interrupt
+; To check if the drawing engine is busy with the previous swap you can
+; call tgi_ioctl(4, 0). It returns 0 if idle and 1 if busy