Changes
CRTC
,/* HCC (C0) overflow */
If Horizontal Total (R0) is changed with a value less than the current HCC, then:
* on CRTCs 0/1/2, HCC overflows and will count up to its maximum value (255) before looping backand counting up again until it reaches the new value of R0
* on CRTCs 3/4, the current line is considered finished and HCC is immediately reset to 0 on the next line
