Changes
CRTC
,/* VSC (C3h) overflow */
=== VSC (C3h) overflow ===
During a VSYNC on CRTCs 0/3/4, if VSYNC Width (R3h) is changed with a value less than the current VSC, then VSC overflows and will continue to count up to its maximum value (15) before looping backand counting up again until it reaches the new value of R3h.
On CRTCs 1/2, the VSYNC width is fixed to 16 characters. It is not possible to modify it. Therefore, VSC cannot be overflowed.
