==== Contiguous HSYNCs ====
On CRTC 0, two HSYNCs cannot be contiguous. They are always separated by at least 1 CRTC character.What happens is that when HSC=R3 and HCC=R2, the condition HSC=R3 takes precedence over the condition HCC=R2 and HSYNC is stopped.
On CRTCs 1/2/3/4, HSYNCs can be contiguous.