As an exception, on CRTCs 3/4, if R7=0 then mid-VSYNC will instead occur on the odd field.
=== Subpixel hardware vertical hardware scroll ===
By tuning very precisely when the VSYNC signal is sent to the monitor, Longshot has demonstrated [https://youtu.be/bSjRU6Wye00 hardware vertical scroll] with a precision of 1/128th of a pixel. Furthermore, subpixel vertical scrolling consumes very little CPU.