Changes
CRTC
,/* VTAC overflow */
During vertical adjustment, if Vertical Total Adjust (R5) is changed with a value less than the current VTAC, then:
* on CRTCs 0/1/2, VTAC overflows and continues to count up to 0 to reach new R5 its maximum value(31) before looping
* on CRTCs 3/4, the current line is considered the last one and vertical adjustment ends
