I did that for A game in DOS days. It needed a virtual retrace interrupt using a timer interrupt to trigger shortly before retrace, busy waiting until retrace

I did that for A game in DOS days. It needed a virtual retrace interrupt using a timer interrupt to trigger shortly before retrace, busy waiting until retrace then recalibrating the timer for the next frame. Pretty soon after that Operating Systems managed memory and interrupts themselves. The added latency on timers made precision tricks like that impractical.