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=== Overflow during HSYNC HSC (C3l) overflow ===
During an HSYNC, if HSYNC Width (R3l) is changed with a value less than the current HSC, then HSC is overflowing. The only exception is for CRTC 1 with a value of 0, which cancels the current HSYNC.
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=== Overflow during Vertical Adjustment VLC (C9) overflow === If Number of Scan Lines (R9) is updated with a value less than the current VLC, then:* on CRTCs 0/1/2, VLC will count to its maximum value (31) before looping* on CRTCs 3/4, the current line is considered the last one of this CRTC character and VLC changes to 0 on the next line <br> === 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 CRTC CRTCs 3/4, the current line is considered the last one and additional management vertical adjustment ends
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