/************************************************************************/
/* Wait for start of next vertical retrace                              */
/************************************************************************/

wait_4_vert()
        {
        int i;
        long int count, ticks();
        printf("\n...counting");
        count = ticks();                        /* Get current tick     */
        for (i = 0; i < 300; i++)
                vertical_retrace();             /* Wait for start of    */
                                                /* next vertical retrace*/
        count = ticks() - count;
        printf("\n300 vertical retraces took %ld ticks",count);
        printf("\nThat is %d cycle refresh rate",
                (300 * (long)91)/(5 * count));
        }