For example, if CRTC R2=46, and CRTC HSYNC width is 14 chars then C-HSYNC starts at 48 and lasts only until 51 included.
On Gate Array, even if the duration of the CRTC VSYNC is reduced to 2 µseconds, the Gate Array will always output black for 26 lines with 4 lines of C-VSYNC to the monitor. While on ASIC/Pre-ASIC, the CRTC VSYNC must be active for as long as the C-VSYNC signal to be is sent by the ASIC to the monitor.
The Gate Array (and ASIC/Pre-ASIC) uses 2 internal counters to create its CSYNC signal: